i2c: Bitbanging I2C bus driver using the GPIO API
This is a very simple bitbanging I2C bus driver utilizing the new
arch-neutral GPIO API. Useful for chips that don't have a built-in
I2C controller, additional I2C busses, or testing purposes.
To use, include something similar to the following in the
board-specific setup code:
#include <linux/i2c-gpio.h>
static struct i2c_gpio_platform_data i2c_gpio_data = {
.sda_pin = GPIO_PIN_FOO,
.scl_pin = GPIO_PIN_BAR,
};
static struct platform_device i2c_gpio_device = {
.name = "i2c-gpio",
.id = 0,
.dev = {
.platform_data = &i2c_gpio_data,
},
};
Register this platform_device, set up the I2C pins as GPIO if
required and you're ready to go. This will use default values for
udelay and timeout, and will work with GPIO hardware that does not
support open drain mode, but allows sensing of the SDA and SCL lines
even when they are being driven.
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2007-05-02 05:26:34 +08:00
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/*
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* Bitbanging I2C bus driver using the GPIO API
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*
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* Copyright (C) 2007 Atmel Corporation
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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2019-02-20 00:39:45 +08:00
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#include <linux/completion.h>
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2017-11-28 23:53:32 +08:00
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#include <linux/debugfs.h>
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#include <linux/delay.h>
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2019-01-19 20:16:55 +08:00
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#include <linux/gpio/consumer.h>
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i2c: Bitbanging I2C bus driver using the GPIO API
This is a very simple bitbanging I2C bus driver utilizing the new
arch-neutral GPIO API. Useful for chips that don't have a built-in
I2C controller, additional I2C busses, or testing purposes.
To use, include something similar to the following in the
board-specific setup code:
#include <linux/i2c-gpio.h>
static struct i2c_gpio_platform_data i2c_gpio_data = {
.sda_pin = GPIO_PIN_FOO,
.scl_pin = GPIO_PIN_BAR,
};
static struct platform_device i2c_gpio_device = {
.name = "i2c-gpio",
.id = 0,
.dev = {
.platform_data = &i2c_gpio_data,
},
};
Register this platform_device, set up the I2C pins as GPIO if
required and you're ready to go. This will use default values for
udelay and timeout, and will work with GPIO hardware that does not
support open drain mode, but allows sensing of the SDA and SCL lines
even when they are being driven.
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2007-05-02 05:26:34 +08:00
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#include <linux/i2c-algo-bit.h>
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2019-01-19 20:16:55 +08:00
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#include <linux/i2c.h>
|
i2c: Bitbanging I2C bus driver using the GPIO API
This is a very simple bitbanging I2C bus driver utilizing the new
arch-neutral GPIO API. Useful for chips that don't have a built-in
I2C controller, additional I2C busses, or testing purposes.
To use, include something similar to the following in the
board-specific setup code:
#include <linux/i2c-gpio.h>
static struct i2c_gpio_platform_data i2c_gpio_data = {
.sda_pin = GPIO_PIN_FOO,
.scl_pin = GPIO_PIN_BAR,
};
static struct platform_device i2c_gpio_device = {
.name = "i2c-gpio",
.id = 0,
.dev = {
.platform_data = &i2c_gpio_data,
},
};
Register this platform_device, set up the I2C pins as GPIO if
required and you're ready to go. This will use default values for
udelay and timeout, and will work with GPIO hardware that does not
support open drain mode, but allows sensing of the SDA and SCL lines
even when they are being driven.
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2007-05-02 05:26:34 +08:00
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#include <linux/init.h>
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2019-02-20 00:39:45 +08:00
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#include <linux/interrupt.h>
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i2c: Bitbanging I2C bus driver using the GPIO API
This is a very simple bitbanging I2C bus driver utilizing the new
arch-neutral GPIO API. Useful for chips that don't have a built-in
I2C controller, additional I2C busses, or testing purposes.
To use, include something similar to the following in the
board-specific setup code:
#include <linux/i2c-gpio.h>
static struct i2c_gpio_platform_data i2c_gpio_data = {
.sda_pin = GPIO_PIN_FOO,
.scl_pin = GPIO_PIN_BAR,
};
static struct platform_device i2c_gpio_device = {
.name = "i2c-gpio",
.id = 0,
.dev = {
.platform_data = &i2c_gpio_data,
},
};
Register this platform_device, set up the I2C pins as GPIO if
required and you're ready to go. This will use default values for
udelay and timeout, and will work with GPIO hardware that does not
support open drain mode, but allows sensing of the SDA and SCL lines
even when they are being driven.
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2007-05-02 05:26:34 +08:00
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#include <linux/module.h>
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2013-10-16 17:56:33 +08:00
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#include <linux/of.h>
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2019-01-19 20:16:55 +08:00
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#include <linux/platform_data/i2c-gpio.h>
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#include <linux/platform_device.h>
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#include <linux/slab.h>
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2012-02-05 18:22:34 +08:00
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struct i2c_gpio_private_data {
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i2c: gpio: Convert to use descriptors
This converts the GPIO-based I2C-driver to using GPIO
descriptors instead of the old global numberspace-based
GPIO interface. We:
- Convert the driver to unconditionally grab two GPIOs
from the device by index 0 (SDA) and 1 (SCL) which
will work fine with device tree and descriptor tables.
The existing device trees will continue to work just
like before, but without any roundtrip through the
global numberspace.
- Brutally convert all boardfiles still passing global
GPIOs by registering descriptor tables associated with
the devices instead so this driver does not need to keep
supporting passing any GPIO numbers as platform data.
There is no stepwise approach as elegant as this, I
strongly prefer this big hammer over any antsteps for this
conversion. This way the old GPIO numbers go away and
NEVER COME BACK.
Special conversion for the different boards utilizing
I2C-GPIO:
- EP93xx (arch/arm/mach-ep93xx): pretty straight forward as
all boards were using the same two GPIO lines, just define
these two in a lookup table for "i2c-gpio" and register
these along with the device. None of them define any
other platform data so just pass NULL as platform data.
This platform selects GPIOLIB so all should be smooth.
The pins appear on a gpiochip for bank "G" as pins 1 (SDA)
and 0 (SCL).
- IXP4 (arch/arm/mach-ixp4): descriptor tables have to
be registered for each board separately. They all use
"IXP4XX_GPIO_CHIP" so it is pretty straight forward.
Most board define no other platform data than SCL/SDA
so they can drop the #include of <linux/i2c-gpio.h> and
assign NULL to platform data.
The "goramo_mlr" (Goramo Multilink Router) board is a bit
worrisome: it implements its own I2C bit-banging in the
board file, and optionally registers an I2C serial port,
but claims the same GPIO lines for itself in the board file.
This is not going to work: there will be competition for the
GPIO lines, so delete the optional extra I2C bus instead, no
I2C devices are registered on it anyway, there are just hints
that it may contain an EEPROM that may be accessed from
userspace. This needs to be fixed up properly by the serial
clock using I2C emulation so drop a note in the code.
- KS8695 board acs5k (arch/arm/mach-ks8695/board-acs5.c)
has some platform data in addition to the pins so it needs to
be kept around sans GPIO lines. Its GPIO chip is named
"KS8695" and the arch selects GPIOLIB.
- PXA boards (arch/arm/mach-pxa/*) use some of the platform
data so it needs to be preserved here. The viper board even
registers two GPIO I2Cs. The gpiochip is named "gpio-pxa" and
the arch selects GPIOLIB.
- SA1100 Simpad (arch/arm/mach-sa1100/simpad.c) defines a GPIO
I2C bus, and the arch selects GPIOLIB.
- Blackfin boards (arch/blackfin/bf533 etc) for these I assume
their I2C GPIOs refer to the local gpiochip defined in
arch/blackfin/kernel/bfin_gpio.c names "BFIN-GPIO".
The arch selects GPIOLIB. The boards get spiked with
IF_ENABLED(I2C_GPIO) but that is a side effect of it
being like that already (I would just have Kconfig select
I2C_GPIO and get rid of them all.) I also delete any
platform data set to 0 as it will get that value anyway
from static declartions of platform data.
- The MIPS selects GPIOLIB and the Alchemy machine is using
two local GPIO chips, one of them has a GPIO I2C. We need
to adjust the local offset from the global number space here.
The ATH79 has a proper GPIO driver in drivers/gpio/gpio-ath79.c
and AFAICT the chip is named "ath79-gpio" and the PB44
PCF857x expander spawns from this on GPIO 1 and 0. The latter
board only use the platform data to specify pins so it can be
cut altogether after this.
- The MFD Silicon Motion SM501 is a special case. It dynamically
spawns an I2C bus off the MFD using sm501_create_subdev().
We use an approach to dynamically create a machine descriptor
table and attach this to the "SM501-LOW" or "SM501-HIGH"
gpiochip. We use chip-local offsets to grab the right lines.
We can get rid of two local static inline helpers as part
of this refactoring.
Cc: Steven Miao <realmz6@gmail.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Magnus Damm <magnus.damm@gmail.com>
Cc: Ben Dooks <ben.dooks@codethink.co.uk>
Cc: Heiko Schocher <hs@denx.de>
Acked-by: Wu, Aaron <Aaron.Wu@analog.com>
Acked-by: Olof Johansson <olof@lixom.net>
Acked-by: Lee Jones <lee.jones@linaro.org>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2017-09-10 07:30:46 +08:00
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struct gpio_desc *sda;
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struct gpio_desc *scl;
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2012-02-05 18:22:34 +08:00
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struct i2c_adapter adap;
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struct i2c_algo_bit_data bit_data;
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struct i2c_gpio_platform_data pdata;
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2017-11-28 23:53:32 +08:00
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#ifdef CONFIG_I2C_GPIO_FAULT_INJECTOR
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struct dentry *debug_dir;
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2019-02-20 00:39:45 +08:00
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/* these must be protected by bus lock */
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struct completion scl_irq_completion;
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u64 scl_irq_data;
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2017-11-28 23:53:32 +08:00
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#endif
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2012-02-05 18:22:34 +08:00
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};
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i2c: Bitbanging I2C bus driver using the GPIO API
This is a very simple bitbanging I2C bus driver utilizing the new
arch-neutral GPIO API. Useful for chips that don't have a built-in
I2C controller, additional I2C busses, or testing purposes.
To use, include something similar to the following in the
board-specific setup code:
#include <linux/i2c-gpio.h>
static struct i2c_gpio_platform_data i2c_gpio_data = {
.sda_pin = GPIO_PIN_FOO,
.scl_pin = GPIO_PIN_BAR,
};
static struct platform_device i2c_gpio_device = {
.name = "i2c-gpio",
.id = 0,
.dev = {
.platform_data = &i2c_gpio_data,
},
};
Register this platform_device, set up the I2C pins as GPIO if
required and you're ready to go. This will use default values for
udelay and timeout, and will work with GPIO hardware that does not
support open drain mode, but allows sensing of the SDA and SCL lines
even when they are being driven.
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2007-05-02 05:26:34 +08:00
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/*
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* Toggle SDA by changing the output value of the pin. This is only
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* valid for pins configured as open drain (i.e. setting the value
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* high effectively turns off the output driver.)
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*/
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static void i2c_gpio_setsda_val(void *data, int state)
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{
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i2c: gpio: Convert to use descriptors
This converts the GPIO-based I2C-driver to using GPIO
descriptors instead of the old global numberspace-based
GPIO interface. We:
- Convert the driver to unconditionally grab two GPIOs
from the device by index 0 (SDA) and 1 (SCL) which
will work fine with device tree and descriptor tables.
The existing device trees will continue to work just
like before, but without any roundtrip through the
global numberspace.
- Brutally convert all boardfiles still passing global
GPIOs by registering descriptor tables associated with
the devices instead so this driver does not need to keep
supporting passing any GPIO numbers as platform data.
There is no stepwise approach as elegant as this, I
strongly prefer this big hammer over any antsteps for this
conversion. This way the old GPIO numbers go away and
NEVER COME BACK.
Special conversion for the different boards utilizing
I2C-GPIO:
- EP93xx (arch/arm/mach-ep93xx): pretty straight forward as
all boards were using the same two GPIO lines, just define
these two in a lookup table for "i2c-gpio" and register
these along with the device. None of them define any
other platform data so just pass NULL as platform data.
This platform selects GPIOLIB so all should be smooth.
The pins appear on a gpiochip for bank "G" as pins 1 (SDA)
and 0 (SCL).
- IXP4 (arch/arm/mach-ixp4): descriptor tables have to
be registered for each board separately. They all use
"IXP4XX_GPIO_CHIP" so it is pretty straight forward.
Most board define no other platform data than SCL/SDA
so they can drop the #include of <linux/i2c-gpio.h> and
assign NULL to platform data.
The "goramo_mlr" (Goramo Multilink Router) board is a bit
worrisome: it implements its own I2C bit-banging in the
board file, and optionally registers an I2C serial port,
but claims the same GPIO lines for itself in the board file.
This is not going to work: there will be competition for the
GPIO lines, so delete the optional extra I2C bus instead, no
I2C devices are registered on it anyway, there are just hints
that it may contain an EEPROM that may be accessed from
userspace. This needs to be fixed up properly by the serial
clock using I2C emulation so drop a note in the code.
- KS8695 board acs5k (arch/arm/mach-ks8695/board-acs5.c)
has some platform data in addition to the pins so it needs to
be kept around sans GPIO lines. Its GPIO chip is named
"KS8695" and the arch selects GPIOLIB.
- PXA boards (arch/arm/mach-pxa/*) use some of the platform
data so it needs to be preserved here. The viper board even
registers two GPIO I2Cs. The gpiochip is named "gpio-pxa" and
the arch selects GPIOLIB.
- SA1100 Simpad (arch/arm/mach-sa1100/simpad.c) defines a GPIO
I2C bus, and the arch selects GPIOLIB.
- Blackfin boards (arch/blackfin/bf533 etc) for these I assume
their I2C GPIOs refer to the local gpiochip defined in
arch/blackfin/kernel/bfin_gpio.c names "BFIN-GPIO".
The arch selects GPIOLIB. The boards get spiked with
IF_ENABLED(I2C_GPIO) but that is a side effect of it
being like that already (I would just have Kconfig select
I2C_GPIO and get rid of them all.) I also delete any
platform data set to 0 as it will get that value anyway
from static declartions of platform data.
- The MIPS selects GPIOLIB and the Alchemy machine is using
two local GPIO chips, one of them has a GPIO I2C. We need
to adjust the local offset from the global number space here.
The ATH79 has a proper GPIO driver in drivers/gpio/gpio-ath79.c
and AFAICT the chip is named "ath79-gpio" and the PB44
PCF857x expander spawns from this on GPIO 1 and 0. The latter
board only use the platform data to specify pins so it can be
cut altogether after this.
- The MFD Silicon Motion SM501 is a special case. It dynamically
spawns an I2C bus off the MFD using sm501_create_subdev().
We use an approach to dynamically create a machine descriptor
table and attach this to the "SM501-LOW" or "SM501-HIGH"
gpiochip. We use chip-local offsets to grab the right lines.
We can get rid of two local static inline helpers as part
of this refactoring.
Cc: Steven Miao <realmz6@gmail.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Magnus Damm <magnus.damm@gmail.com>
Cc: Ben Dooks <ben.dooks@codethink.co.uk>
Cc: Heiko Schocher <hs@denx.de>
Acked-by: Wu, Aaron <Aaron.Wu@analog.com>
Acked-by: Olof Johansson <olof@lixom.net>
Acked-by: Lee Jones <lee.jones@linaro.org>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2017-09-10 07:30:46 +08:00
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struct i2c_gpio_private_data *priv = data;
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i2c: Bitbanging I2C bus driver using the GPIO API
This is a very simple bitbanging I2C bus driver utilizing the new
arch-neutral GPIO API. Useful for chips that don't have a built-in
I2C controller, additional I2C busses, or testing purposes.
To use, include something similar to the following in the
board-specific setup code:
#include <linux/i2c-gpio.h>
static struct i2c_gpio_platform_data i2c_gpio_data = {
.sda_pin = GPIO_PIN_FOO,
.scl_pin = GPIO_PIN_BAR,
};
static struct platform_device i2c_gpio_device = {
.name = "i2c-gpio",
.id = 0,
.dev = {
.platform_data = &i2c_gpio_data,
},
};
Register this platform_device, set up the I2C pins as GPIO if
required and you're ready to go. This will use default values for
udelay and timeout, and will work with GPIO hardware that does not
support open drain mode, but allows sensing of the SDA and SCL lines
even when they are being driven.
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2007-05-02 05:26:34 +08:00
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i2c: gpio: Enable working over slow can_sleep GPIOs
"Slow" GPIOs (usually those connected over an SPI or an I2C bus) are,
well, slow in their operation. It is generally a good idea to avoid
using them for time-critical operation, but sometimes the hardware just
sucks, and the software has to cope. In addition to that, the I2C bus
itself does not actually define any strict timing limits; the bus is
free to go all the way down to DC. The timeouts (and therefore the
slowest acceptable frequency) are present only in SMBus.
The `can_sleep` is IMHO a wrong concept to use here. My SPI-to-quad-UART
chip (MAX14830) is connected via a 26MHz SPI bus, and it happily drives
SCL at 200kHz (5µs pulses) during my benchmarks. That's faster than the
maximal allowed speed of the traditional I2C.
The previous version of this code did not really block operation over
slow GPIO pins, anyway. Instead, it just resorted to printing a warning
with a backtrace each time a GPIO pin was accessed, thereby slowing
things down even more.
Finally, it's not just me. A similar patch was originally submitted in
2015 [1].
[1] https://patchwork.ozlabs.org/patch/450956/
Signed-off-by: Jan Kundrát <jan.kundrat@cesnet.cz>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2017-12-23 05:47:16 +08:00
|
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gpiod_set_value_cansleep(priv->sda, state);
|
i2c: Bitbanging I2C bus driver using the GPIO API
This is a very simple bitbanging I2C bus driver utilizing the new
arch-neutral GPIO API. Useful for chips that don't have a built-in
I2C controller, additional I2C busses, or testing purposes.
To use, include something similar to the following in the
board-specific setup code:
#include <linux/i2c-gpio.h>
static struct i2c_gpio_platform_data i2c_gpio_data = {
.sda_pin = GPIO_PIN_FOO,
.scl_pin = GPIO_PIN_BAR,
};
static struct platform_device i2c_gpio_device = {
.name = "i2c-gpio",
.id = 0,
.dev = {
.platform_data = &i2c_gpio_data,
},
};
Register this platform_device, set up the I2C pins as GPIO if
required and you're ready to go. This will use default values for
udelay and timeout, and will work with GPIO hardware that does not
support open drain mode, but allows sensing of the SDA and SCL lines
even when they are being driven.
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2007-05-02 05:26:34 +08:00
|
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}
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|
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/*
|
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* Toggle SCL by changing the output value of the pin. This is used
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* for pins that are configured as open drain and for output-only
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* pins. The latter case will break the i2c protocol, but it will
|
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* often work in practice.
|
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|
*/
|
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static void i2c_gpio_setscl_val(void *data, int state)
|
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{
|
i2c: gpio: Convert to use descriptors
This converts the GPIO-based I2C-driver to using GPIO
descriptors instead of the old global numberspace-based
GPIO interface. We:
- Convert the driver to unconditionally grab two GPIOs
from the device by index 0 (SDA) and 1 (SCL) which
will work fine with device tree and descriptor tables.
The existing device trees will continue to work just
like before, but without any roundtrip through the
global numberspace.
- Brutally convert all boardfiles still passing global
GPIOs by registering descriptor tables associated with
the devices instead so this driver does not need to keep
supporting passing any GPIO numbers as platform data.
There is no stepwise approach as elegant as this, I
strongly prefer this big hammer over any antsteps for this
conversion. This way the old GPIO numbers go away and
NEVER COME BACK.
Special conversion for the different boards utilizing
I2C-GPIO:
- EP93xx (arch/arm/mach-ep93xx): pretty straight forward as
all boards were using the same two GPIO lines, just define
these two in a lookup table for "i2c-gpio" and register
these along with the device. None of them define any
other platform data so just pass NULL as platform data.
This platform selects GPIOLIB so all should be smooth.
The pins appear on a gpiochip for bank "G" as pins 1 (SDA)
and 0 (SCL).
- IXP4 (arch/arm/mach-ixp4): descriptor tables have to
be registered for each board separately. They all use
"IXP4XX_GPIO_CHIP" so it is pretty straight forward.
Most board define no other platform data than SCL/SDA
so they can drop the #include of <linux/i2c-gpio.h> and
assign NULL to platform data.
The "goramo_mlr" (Goramo Multilink Router) board is a bit
worrisome: it implements its own I2C bit-banging in the
board file, and optionally registers an I2C serial port,
but claims the same GPIO lines for itself in the board file.
This is not going to work: there will be competition for the
GPIO lines, so delete the optional extra I2C bus instead, no
I2C devices are registered on it anyway, there are just hints
that it may contain an EEPROM that may be accessed from
userspace. This needs to be fixed up properly by the serial
clock using I2C emulation so drop a note in the code.
- KS8695 board acs5k (arch/arm/mach-ks8695/board-acs5.c)
has some platform data in addition to the pins so it needs to
be kept around sans GPIO lines. Its GPIO chip is named
"KS8695" and the arch selects GPIOLIB.
- PXA boards (arch/arm/mach-pxa/*) use some of the platform
data so it needs to be preserved here. The viper board even
registers two GPIO I2Cs. The gpiochip is named "gpio-pxa" and
the arch selects GPIOLIB.
- SA1100 Simpad (arch/arm/mach-sa1100/simpad.c) defines a GPIO
I2C bus, and the arch selects GPIOLIB.
- Blackfin boards (arch/blackfin/bf533 etc) for these I assume
their I2C GPIOs refer to the local gpiochip defined in
arch/blackfin/kernel/bfin_gpio.c names "BFIN-GPIO".
The arch selects GPIOLIB. The boards get spiked with
IF_ENABLED(I2C_GPIO) but that is a side effect of it
being like that already (I would just have Kconfig select
I2C_GPIO and get rid of them all.) I also delete any
platform data set to 0 as it will get that value anyway
from static declartions of platform data.
- The MIPS selects GPIOLIB and the Alchemy machine is using
two local GPIO chips, one of them has a GPIO I2C. We need
to adjust the local offset from the global number space here.
The ATH79 has a proper GPIO driver in drivers/gpio/gpio-ath79.c
and AFAICT the chip is named "ath79-gpio" and the PB44
PCF857x expander spawns from this on GPIO 1 and 0. The latter
board only use the platform data to specify pins so it can be
cut altogether after this.
- The MFD Silicon Motion SM501 is a special case. It dynamically
spawns an I2C bus off the MFD using sm501_create_subdev().
We use an approach to dynamically create a machine descriptor
table and attach this to the "SM501-LOW" or "SM501-HIGH"
gpiochip. We use chip-local offsets to grab the right lines.
We can get rid of two local static inline helpers as part
of this refactoring.
Cc: Steven Miao <realmz6@gmail.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Magnus Damm <magnus.damm@gmail.com>
Cc: Ben Dooks <ben.dooks@codethink.co.uk>
Cc: Heiko Schocher <hs@denx.de>
Acked-by: Wu, Aaron <Aaron.Wu@analog.com>
Acked-by: Olof Johansson <olof@lixom.net>
Acked-by: Lee Jones <lee.jones@linaro.org>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2017-09-10 07:30:46 +08:00
|
|
|
struct i2c_gpio_private_data *priv = data;
|
i2c: Bitbanging I2C bus driver using the GPIO API
This is a very simple bitbanging I2C bus driver utilizing the new
arch-neutral GPIO API. Useful for chips that don't have a built-in
I2C controller, additional I2C busses, or testing purposes.
To use, include something similar to the following in the
board-specific setup code:
#include <linux/i2c-gpio.h>
static struct i2c_gpio_platform_data i2c_gpio_data = {
.sda_pin = GPIO_PIN_FOO,
.scl_pin = GPIO_PIN_BAR,
};
static struct platform_device i2c_gpio_device = {
.name = "i2c-gpio",
.id = 0,
.dev = {
.platform_data = &i2c_gpio_data,
},
};
Register this platform_device, set up the I2C pins as GPIO if
required and you're ready to go. This will use default values for
udelay and timeout, and will work with GPIO hardware that does not
support open drain mode, but allows sensing of the SDA and SCL lines
even when they are being driven.
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2007-05-02 05:26:34 +08:00
|
|
|
|
i2c: gpio: Enable working over slow can_sleep GPIOs
"Slow" GPIOs (usually those connected over an SPI or an I2C bus) are,
well, slow in their operation. It is generally a good idea to avoid
using them for time-critical operation, but sometimes the hardware just
sucks, and the software has to cope. In addition to that, the I2C bus
itself does not actually define any strict timing limits; the bus is
free to go all the way down to DC. The timeouts (and therefore the
slowest acceptable frequency) are present only in SMBus.
The `can_sleep` is IMHO a wrong concept to use here. My SPI-to-quad-UART
chip (MAX14830) is connected via a 26MHz SPI bus, and it happily drives
SCL at 200kHz (5µs pulses) during my benchmarks. That's faster than the
maximal allowed speed of the traditional I2C.
The previous version of this code did not really block operation over
slow GPIO pins, anyway. Instead, it just resorted to printing a warning
with a backtrace each time a GPIO pin was accessed, thereby slowing
things down even more.
Finally, it's not just me. A similar patch was originally submitted in
2015 [1].
[1] https://patchwork.ozlabs.org/patch/450956/
Signed-off-by: Jan Kundrát <jan.kundrat@cesnet.cz>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2017-12-23 05:47:16 +08:00
|
|
|
gpiod_set_value_cansleep(priv->scl, state);
|
i2c: Bitbanging I2C bus driver using the GPIO API
This is a very simple bitbanging I2C bus driver utilizing the new
arch-neutral GPIO API. Useful for chips that don't have a built-in
I2C controller, additional I2C busses, or testing purposes.
To use, include something similar to the following in the
board-specific setup code:
#include <linux/i2c-gpio.h>
static struct i2c_gpio_platform_data i2c_gpio_data = {
.sda_pin = GPIO_PIN_FOO,
.scl_pin = GPIO_PIN_BAR,
};
static struct platform_device i2c_gpio_device = {
.name = "i2c-gpio",
.id = 0,
.dev = {
.platform_data = &i2c_gpio_data,
},
};
Register this platform_device, set up the I2C pins as GPIO if
required and you're ready to go. This will use default values for
udelay and timeout, and will work with GPIO hardware that does not
support open drain mode, but allows sensing of the SDA and SCL lines
even when they are being driven.
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2007-05-02 05:26:34 +08:00
|
|
|
}
|
|
|
|
|
2007-07-12 20:12:30 +08:00
|
|
|
static int i2c_gpio_getsda(void *data)
|
i2c: Bitbanging I2C bus driver using the GPIO API
This is a very simple bitbanging I2C bus driver utilizing the new
arch-neutral GPIO API. Useful for chips that don't have a built-in
I2C controller, additional I2C busses, or testing purposes.
To use, include something similar to the following in the
board-specific setup code:
#include <linux/i2c-gpio.h>
static struct i2c_gpio_platform_data i2c_gpio_data = {
.sda_pin = GPIO_PIN_FOO,
.scl_pin = GPIO_PIN_BAR,
};
static struct platform_device i2c_gpio_device = {
.name = "i2c-gpio",
.id = 0,
.dev = {
.platform_data = &i2c_gpio_data,
},
};
Register this platform_device, set up the I2C pins as GPIO if
required and you're ready to go. This will use default values for
udelay and timeout, and will work with GPIO hardware that does not
support open drain mode, but allows sensing of the SDA and SCL lines
even when they are being driven.
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2007-05-02 05:26:34 +08:00
|
|
|
{
|
i2c: gpio: Convert to use descriptors
This converts the GPIO-based I2C-driver to using GPIO
descriptors instead of the old global numberspace-based
GPIO interface. We:
- Convert the driver to unconditionally grab two GPIOs
from the device by index 0 (SDA) and 1 (SCL) which
will work fine with device tree and descriptor tables.
The existing device trees will continue to work just
like before, but without any roundtrip through the
global numberspace.
- Brutally convert all boardfiles still passing global
GPIOs by registering descriptor tables associated with
the devices instead so this driver does not need to keep
supporting passing any GPIO numbers as platform data.
There is no stepwise approach as elegant as this, I
strongly prefer this big hammer over any antsteps for this
conversion. This way the old GPIO numbers go away and
NEVER COME BACK.
Special conversion for the different boards utilizing
I2C-GPIO:
- EP93xx (arch/arm/mach-ep93xx): pretty straight forward as
all boards were using the same two GPIO lines, just define
these two in a lookup table for "i2c-gpio" and register
these along with the device. None of them define any
other platform data so just pass NULL as platform data.
This platform selects GPIOLIB so all should be smooth.
The pins appear on a gpiochip for bank "G" as pins 1 (SDA)
and 0 (SCL).
- IXP4 (arch/arm/mach-ixp4): descriptor tables have to
be registered for each board separately. They all use
"IXP4XX_GPIO_CHIP" so it is pretty straight forward.
Most board define no other platform data than SCL/SDA
so they can drop the #include of <linux/i2c-gpio.h> and
assign NULL to platform data.
The "goramo_mlr" (Goramo Multilink Router) board is a bit
worrisome: it implements its own I2C bit-banging in the
board file, and optionally registers an I2C serial port,
but claims the same GPIO lines for itself in the board file.
This is not going to work: there will be competition for the
GPIO lines, so delete the optional extra I2C bus instead, no
I2C devices are registered on it anyway, there are just hints
that it may contain an EEPROM that may be accessed from
userspace. This needs to be fixed up properly by the serial
clock using I2C emulation so drop a note in the code.
- KS8695 board acs5k (arch/arm/mach-ks8695/board-acs5.c)
has some platform data in addition to the pins so it needs to
be kept around sans GPIO lines. Its GPIO chip is named
"KS8695" and the arch selects GPIOLIB.
- PXA boards (arch/arm/mach-pxa/*) use some of the platform
data so it needs to be preserved here. The viper board even
registers two GPIO I2Cs. The gpiochip is named "gpio-pxa" and
the arch selects GPIOLIB.
- SA1100 Simpad (arch/arm/mach-sa1100/simpad.c) defines a GPIO
I2C bus, and the arch selects GPIOLIB.
- Blackfin boards (arch/blackfin/bf533 etc) for these I assume
their I2C GPIOs refer to the local gpiochip defined in
arch/blackfin/kernel/bfin_gpio.c names "BFIN-GPIO".
The arch selects GPIOLIB. The boards get spiked with
IF_ENABLED(I2C_GPIO) but that is a side effect of it
being like that already (I would just have Kconfig select
I2C_GPIO and get rid of them all.) I also delete any
platform data set to 0 as it will get that value anyway
from static declartions of platform data.
- The MIPS selects GPIOLIB and the Alchemy machine is using
two local GPIO chips, one of them has a GPIO I2C. We need
to adjust the local offset from the global number space here.
The ATH79 has a proper GPIO driver in drivers/gpio/gpio-ath79.c
and AFAICT the chip is named "ath79-gpio" and the PB44
PCF857x expander spawns from this on GPIO 1 and 0. The latter
board only use the platform data to specify pins so it can be
cut altogether after this.
- The MFD Silicon Motion SM501 is a special case. It dynamically
spawns an I2C bus off the MFD using sm501_create_subdev().
We use an approach to dynamically create a machine descriptor
table and attach this to the "SM501-LOW" or "SM501-HIGH"
gpiochip. We use chip-local offsets to grab the right lines.
We can get rid of two local static inline helpers as part
of this refactoring.
Cc: Steven Miao <realmz6@gmail.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Magnus Damm <magnus.damm@gmail.com>
Cc: Ben Dooks <ben.dooks@codethink.co.uk>
Cc: Heiko Schocher <hs@denx.de>
Acked-by: Wu, Aaron <Aaron.Wu@analog.com>
Acked-by: Olof Johansson <olof@lixom.net>
Acked-by: Lee Jones <lee.jones@linaro.org>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2017-09-10 07:30:46 +08:00
|
|
|
struct i2c_gpio_private_data *priv = data;
|
i2c: Bitbanging I2C bus driver using the GPIO API
This is a very simple bitbanging I2C bus driver utilizing the new
arch-neutral GPIO API. Useful for chips that don't have a built-in
I2C controller, additional I2C busses, or testing purposes.
To use, include something similar to the following in the
board-specific setup code:
#include <linux/i2c-gpio.h>
static struct i2c_gpio_platform_data i2c_gpio_data = {
.sda_pin = GPIO_PIN_FOO,
.scl_pin = GPIO_PIN_BAR,
};
static struct platform_device i2c_gpio_device = {
.name = "i2c-gpio",
.id = 0,
.dev = {
.platform_data = &i2c_gpio_data,
},
};
Register this platform_device, set up the I2C pins as GPIO if
required and you're ready to go. This will use default values for
udelay and timeout, and will work with GPIO hardware that does not
support open drain mode, but allows sensing of the SDA and SCL lines
even when they are being driven.
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2007-05-02 05:26:34 +08:00
|
|
|
|
i2c: gpio: Enable working over slow can_sleep GPIOs
"Slow" GPIOs (usually those connected over an SPI or an I2C bus) are,
well, slow in their operation. It is generally a good idea to avoid
using them for time-critical operation, but sometimes the hardware just
sucks, and the software has to cope. In addition to that, the I2C bus
itself does not actually define any strict timing limits; the bus is
free to go all the way down to DC. The timeouts (and therefore the
slowest acceptable frequency) are present only in SMBus.
The `can_sleep` is IMHO a wrong concept to use here. My SPI-to-quad-UART
chip (MAX14830) is connected via a 26MHz SPI bus, and it happily drives
SCL at 200kHz (5µs pulses) during my benchmarks. That's faster than the
maximal allowed speed of the traditional I2C.
The previous version of this code did not really block operation over
slow GPIO pins, anyway. Instead, it just resorted to printing a warning
with a backtrace each time a GPIO pin was accessed, thereby slowing
things down even more.
Finally, it's not just me. A similar patch was originally submitted in
2015 [1].
[1] https://patchwork.ozlabs.org/patch/450956/
Signed-off-by: Jan Kundrát <jan.kundrat@cesnet.cz>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2017-12-23 05:47:16 +08:00
|
|
|
return gpiod_get_value_cansleep(priv->sda);
|
i2c: Bitbanging I2C bus driver using the GPIO API
This is a very simple bitbanging I2C bus driver utilizing the new
arch-neutral GPIO API. Useful for chips that don't have a built-in
I2C controller, additional I2C busses, or testing purposes.
To use, include something similar to the following in the
board-specific setup code:
#include <linux/i2c-gpio.h>
static struct i2c_gpio_platform_data i2c_gpio_data = {
.sda_pin = GPIO_PIN_FOO,
.scl_pin = GPIO_PIN_BAR,
};
static struct platform_device i2c_gpio_device = {
.name = "i2c-gpio",
.id = 0,
.dev = {
.platform_data = &i2c_gpio_data,
},
};
Register this platform_device, set up the I2C pins as GPIO if
required and you're ready to go. This will use default values for
udelay and timeout, and will work with GPIO hardware that does not
support open drain mode, but allows sensing of the SDA and SCL lines
even when they are being driven.
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2007-05-02 05:26:34 +08:00
|
|
|
}
|
|
|
|
|
2007-07-12 20:12:30 +08:00
|
|
|
static int i2c_gpio_getscl(void *data)
|
i2c: Bitbanging I2C bus driver using the GPIO API
This is a very simple bitbanging I2C bus driver utilizing the new
arch-neutral GPIO API. Useful for chips that don't have a built-in
I2C controller, additional I2C busses, or testing purposes.
To use, include something similar to the following in the
board-specific setup code:
#include <linux/i2c-gpio.h>
static struct i2c_gpio_platform_data i2c_gpio_data = {
.sda_pin = GPIO_PIN_FOO,
.scl_pin = GPIO_PIN_BAR,
};
static struct platform_device i2c_gpio_device = {
.name = "i2c-gpio",
.id = 0,
.dev = {
.platform_data = &i2c_gpio_data,
},
};
Register this platform_device, set up the I2C pins as GPIO if
required and you're ready to go. This will use default values for
udelay and timeout, and will work with GPIO hardware that does not
support open drain mode, but allows sensing of the SDA and SCL lines
even when they are being driven.
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2007-05-02 05:26:34 +08:00
|
|
|
{
|
i2c: gpio: Convert to use descriptors
This converts the GPIO-based I2C-driver to using GPIO
descriptors instead of the old global numberspace-based
GPIO interface. We:
- Convert the driver to unconditionally grab two GPIOs
from the device by index 0 (SDA) and 1 (SCL) which
will work fine with device tree and descriptor tables.
The existing device trees will continue to work just
like before, but without any roundtrip through the
global numberspace.
- Brutally convert all boardfiles still passing global
GPIOs by registering descriptor tables associated with
the devices instead so this driver does not need to keep
supporting passing any GPIO numbers as platform data.
There is no stepwise approach as elegant as this, I
strongly prefer this big hammer over any antsteps for this
conversion. This way the old GPIO numbers go away and
NEVER COME BACK.
Special conversion for the different boards utilizing
I2C-GPIO:
- EP93xx (arch/arm/mach-ep93xx): pretty straight forward as
all boards were using the same two GPIO lines, just define
these two in a lookup table for "i2c-gpio" and register
these along with the device. None of them define any
other platform data so just pass NULL as platform data.
This platform selects GPIOLIB so all should be smooth.
The pins appear on a gpiochip for bank "G" as pins 1 (SDA)
and 0 (SCL).
- IXP4 (arch/arm/mach-ixp4): descriptor tables have to
be registered for each board separately. They all use
"IXP4XX_GPIO_CHIP" so it is pretty straight forward.
Most board define no other platform data than SCL/SDA
so they can drop the #include of <linux/i2c-gpio.h> and
assign NULL to platform data.
The "goramo_mlr" (Goramo Multilink Router) board is a bit
worrisome: it implements its own I2C bit-banging in the
board file, and optionally registers an I2C serial port,
but claims the same GPIO lines for itself in the board file.
This is not going to work: there will be competition for the
GPIO lines, so delete the optional extra I2C bus instead, no
I2C devices are registered on it anyway, there are just hints
that it may contain an EEPROM that may be accessed from
userspace. This needs to be fixed up properly by the serial
clock using I2C emulation so drop a note in the code.
- KS8695 board acs5k (arch/arm/mach-ks8695/board-acs5.c)
has some platform data in addition to the pins so it needs to
be kept around sans GPIO lines. Its GPIO chip is named
"KS8695" and the arch selects GPIOLIB.
- PXA boards (arch/arm/mach-pxa/*) use some of the platform
data so it needs to be preserved here. The viper board even
registers two GPIO I2Cs. The gpiochip is named "gpio-pxa" and
the arch selects GPIOLIB.
- SA1100 Simpad (arch/arm/mach-sa1100/simpad.c) defines a GPIO
I2C bus, and the arch selects GPIOLIB.
- Blackfin boards (arch/blackfin/bf533 etc) for these I assume
their I2C GPIOs refer to the local gpiochip defined in
arch/blackfin/kernel/bfin_gpio.c names "BFIN-GPIO".
The arch selects GPIOLIB. The boards get spiked with
IF_ENABLED(I2C_GPIO) but that is a side effect of it
being like that already (I would just have Kconfig select
I2C_GPIO and get rid of them all.) I also delete any
platform data set to 0 as it will get that value anyway
from static declartions of platform data.
- The MIPS selects GPIOLIB and the Alchemy machine is using
two local GPIO chips, one of them has a GPIO I2C. We need
to adjust the local offset from the global number space here.
The ATH79 has a proper GPIO driver in drivers/gpio/gpio-ath79.c
and AFAICT the chip is named "ath79-gpio" and the PB44
PCF857x expander spawns from this on GPIO 1 and 0. The latter
board only use the platform data to specify pins so it can be
cut altogether after this.
- The MFD Silicon Motion SM501 is a special case. It dynamically
spawns an I2C bus off the MFD using sm501_create_subdev().
We use an approach to dynamically create a machine descriptor
table and attach this to the "SM501-LOW" or "SM501-HIGH"
gpiochip. We use chip-local offsets to grab the right lines.
We can get rid of two local static inline helpers as part
of this refactoring.
Cc: Steven Miao <realmz6@gmail.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Magnus Damm <magnus.damm@gmail.com>
Cc: Ben Dooks <ben.dooks@codethink.co.uk>
Cc: Heiko Schocher <hs@denx.de>
Acked-by: Wu, Aaron <Aaron.Wu@analog.com>
Acked-by: Olof Johansson <olof@lixom.net>
Acked-by: Lee Jones <lee.jones@linaro.org>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2017-09-10 07:30:46 +08:00
|
|
|
struct i2c_gpio_private_data *priv = data;
|
i2c: Bitbanging I2C bus driver using the GPIO API
This is a very simple bitbanging I2C bus driver utilizing the new
arch-neutral GPIO API. Useful for chips that don't have a built-in
I2C controller, additional I2C busses, or testing purposes.
To use, include something similar to the following in the
board-specific setup code:
#include <linux/i2c-gpio.h>
static struct i2c_gpio_platform_data i2c_gpio_data = {
.sda_pin = GPIO_PIN_FOO,
.scl_pin = GPIO_PIN_BAR,
};
static struct platform_device i2c_gpio_device = {
.name = "i2c-gpio",
.id = 0,
.dev = {
.platform_data = &i2c_gpio_data,
},
};
Register this platform_device, set up the I2C pins as GPIO if
required and you're ready to go. This will use default values for
udelay and timeout, and will work with GPIO hardware that does not
support open drain mode, but allows sensing of the SDA and SCL lines
even when they are being driven.
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2007-05-02 05:26:34 +08:00
|
|
|
|
i2c: gpio: Enable working over slow can_sleep GPIOs
"Slow" GPIOs (usually those connected over an SPI or an I2C bus) are,
well, slow in their operation. It is generally a good idea to avoid
using them for time-critical operation, but sometimes the hardware just
sucks, and the software has to cope. In addition to that, the I2C bus
itself does not actually define any strict timing limits; the bus is
free to go all the way down to DC. The timeouts (and therefore the
slowest acceptable frequency) are present only in SMBus.
The `can_sleep` is IMHO a wrong concept to use here. My SPI-to-quad-UART
chip (MAX14830) is connected via a 26MHz SPI bus, and it happily drives
SCL at 200kHz (5µs pulses) during my benchmarks. That's faster than the
maximal allowed speed of the traditional I2C.
The previous version of this code did not really block operation over
slow GPIO pins, anyway. Instead, it just resorted to printing a warning
with a backtrace each time a GPIO pin was accessed, thereby slowing
things down even more.
Finally, it's not just me. A similar patch was originally submitted in
2015 [1].
[1] https://patchwork.ozlabs.org/patch/450956/
Signed-off-by: Jan Kundrát <jan.kundrat@cesnet.cz>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2017-12-23 05:47:16 +08:00
|
|
|
return gpiod_get_value_cansleep(priv->scl);
|
2013-02-28 09:01:40 +08:00
|
|
|
}
|
|
|
|
|
2017-11-28 23:53:32 +08:00
|
|
|
#ifdef CONFIG_I2C_GPIO_FAULT_INJECTOR
|
|
|
|
static struct dentry *i2c_gpio_debug_dir;
|
|
|
|
|
|
|
|
#define setsda(bd, val) ((bd)->setsda((bd)->data, val))
|
|
|
|
#define setscl(bd, val) ((bd)->setscl((bd)->data, val))
|
|
|
|
#define getsda(bd) ((bd)->getsda((bd)->data))
|
|
|
|
#define getscl(bd) ((bd)->getscl((bd)->data))
|
|
|
|
|
|
|
|
#define WIRE_ATTRIBUTE(wire) \
|
2018-06-20 13:18:03 +08:00
|
|
|
static int fops_##wire##_get(void *data, u64 *val) \
|
|
|
|
{ \
|
|
|
|
struct i2c_gpio_private_data *priv = data; \
|
|
|
|
\
|
|
|
|
i2c_lock_bus(&priv->adap, I2C_LOCK_ROOT_ADAPTER); \
|
|
|
|
*val = get##wire(&priv->bit_data); \
|
|
|
|
i2c_unlock_bus(&priv->adap, I2C_LOCK_ROOT_ADAPTER); \
|
|
|
|
return 0; \
|
|
|
|
} \
|
|
|
|
static int fops_##wire##_set(void *data, u64 val) \
|
|
|
|
{ \
|
|
|
|
struct i2c_gpio_private_data *priv = data; \
|
|
|
|
\
|
|
|
|
i2c_lock_bus(&priv->adap, I2C_LOCK_ROOT_ADAPTER); \
|
|
|
|
set##wire(&priv->bit_data, val); \
|
|
|
|
i2c_unlock_bus(&priv->adap, I2C_LOCK_ROOT_ADAPTER); \
|
|
|
|
return 0; \
|
|
|
|
} \
|
2017-11-28 23:53:32 +08:00
|
|
|
DEFINE_DEBUGFS_ATTRIBUTE(fops_##wire, fops_##wire##_get, fops_##wire##_set, "%llu\n")
|
|
|
|
|
|
|
|
WIRE_ATTRIBUTE(scl);
|
|
|
|
WIRE_ATTRIBUTE(sda);
|
|
|
|
|
2018-06-29 17:12:46 +08:00
|
|
|
static void i2c_gpio_incomplete_transfer(struct i2c_gpio_private_data *priv,
|
|
|
|
u32 pattern, u8 pattern_size)
|
2017-11-28 23:53:32 +08:00
|
|
|
{
|
|
|
|
struct i2c_algo_bit_data *bit_data = &priv->bit_data;
|
2018-06-29 17:12:46 +08:00
|
|
|
int i;
|
2017-11-28 23:53:32 +08:00
|
|
|
|
2018-06-20 13:18:03 +08:00
|
|
|
i2c_lock_bus(&priv->adap, I2C_LOCK_ROOT_ADAPTER);
|
2017-11-28 23:53:32 +08:00
|
|
|
|
|
|
|
/* START condition */
|
|
|
|
setsda(bit_data, 0);
|
|
|
|
udelay(bit_data->udelay);
|
|
|
|
|
2018-06-29 17:12:46 +08:00
|
|
|
/* Send pattern, request ACK, don't send STOP */
|
|
|
|
for (i = pattern_size - 1; i >= 0; i--) {
|
2017-11-28 23:53:32 +08:00
|
|
|
setscl(bit_data, 0);
|
|
|
|
udelay(bit_data->udelay / 2);
|
|
|
|
setsda(bit_data, (pattern >> i) & 1);
|
|
|
|
udelay((bit_data->udelay + 1) / 2);
|
|
|
|
setscl(bit_data, 1);
|
|
|
|
udelay(bit_data->udelay);
|
|
|
|
}
|
|
|
|
|
2018-06-20 13:18:03 +08:00
|
|
|
i2c_unlock_bus(&priv->adap, I2C_LOCK_ROOT_ADAPTER);
|
2018-06-29 17:12:46 +08:00
|
|
|
}
|
|
|
|
|
|
|
|
static int fops_incomplete_addr_phase_set(void *data, u64 addr)
|
|
|
|
{
|
|
|
|
struct i2c_gpio_private_data *priv = data;
|
|
|
|
u32 pattern;
|
|
|
|
|
|
|
|
if (addr > 0x7f)
|
|
|
|
return -EINVAL;
|
|
|
|
|
|
|
|
/* ADDR (7 bit) + RD (1 bit) + Client ACK, keep SDA hi (1 bit) */
|
|
|
|
pattern = (addr << 2) | 3;
|
|
|
|
|
|
|
|
i2c_gpio_incomplete_transfer(priv, pattern, 9);
|
2017-11-28 23:53:32 +08:00
|
|
|
|
|
|
|
return 0;
|
|
|
|
}
|
2018-06-29 17:12:46 +08:00
|
|
|
DEFINE_DEBUGFS_ATTRIBUTE(fops_incomplete_addr_phase, NULL, fops_incomplete_addr_phase_set, "%llu\n");
|
2017-11-28 23:53:32 +08:00
|
|
|
|
2018-06-29 17:12:47 +08:00
|
|
|
static int fops_incomplete_write_byte_set(void *data, u64 addr)
|
|
|
|
{
|
|
|
|
struct i2c_gpio_private_data *priv = data;
|
|
|
|
u32 pattern;
|
|
|
|
|
|
|
|
if (addr > 0x7f)
|
|
|
|
return -EINVAL;
|
|
|
|
|
|
|
|
/* ADDR (7 bit) + WR (1 bit) + Client ACK (1 bit) */
|
|
|
|
pattern = (addr << 2) | 1;
|
|
|
|
/* 0x00 (8 bit) + Client ACK, keep SDA hi (1 bit) */
|
|
|
|
pattern = (pattern << 9) | 1;
|
|
|
|
|
|
|
|
i2c_gpio_incomplete_transfer(priv, pattern, 18);
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
DEFINE_DEBUGFS_ATTRIBUTE(fops_incomplete_write_byte, NULL, fops_incomplete_write_byte_set, "%llu\n");
|
|
|
|
|
2019-02-20 00:39:45 +08:00
|
|
|
static int i2c_gpio_fi_act_on_scl_irq(struct i2c_gpio_private_data *priv,
|
|
|
|
irqreturn_t handler(int, void*))
|
|
|
|
{
|
|
|
|
int ret, irq = gpiod_to_irq(priv->scl);
|
|
|
|
|
|
|
|
if (irq < 0)
|
|
|
|
return irq;
|
|
|
|
|
|
|
|
i2c_lock_bus(&priv->adap, I2C_LOCK_ROOT_ADAPTER);
|
|
|
|
|
|
|
|
ret = gpiod_direction_input(priv->scl);
|
|
|
|
if (ret)
|
|
|
|
goto unlock;
|
|
|
|
|
|
|
|
reinit_completion(&priv->scl_irq_completion);
|
|
|
|
|
|
|
|
ret = request_irq(irq, handler, IRQF_TRIGGER_FALLING,
|
|
|
|
"i2c_gpio_fault_injector_scl_irq", priv);
|
|
|
|
if (ret)
|
|
|
|
goto output;
|
|
|
|
|
|
|
|
wait_for_completion_interruptible(&priv->scl_irq_completion);
|
|
|
|
|
|
|
|
free_irq(irq, priv);
|
|
|
|
output:
|
|
|
|
ret = gpiod_direction_output(priv->scl, 1) ?: ret;
|
|
|
|
unlock:
|
|
|
|
i2c_unlock_bus(&priv->adap, I2C_LOCK_ROOT_ADAPTER);
|
|
|
|
|
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
|
|
|
static irqreturn_t lose_arbitration_irq(int irq, void *dev_id)
|
|
|
|
{
|
|
|
|
struct i2c_gpio_private_data *priv = dev_id;
|
|
|
|
|
|
|
|
setsda(&priv->bit_data, 0);
|
|
|
|
udelay(priv->scl_irq_data);
|
|
|
|
setsda(&priv->bit_data, 1);
|
|
|
|
|
|
|
|
complete(&priv->scl_irq_completion);
|
|
|
|
|
|
|
|
return IRQ_HANDLED;
|
|
|
|
}
|
|
|
|
|
|
|
|
static int fops_lose_arbitration_set(void *data, u64 duration)
|
|
|
|
{
|
|
|
|
struct i2c_gpio_private_data *priv = data;
|
|
|
|
|
|
|
|
if (duration > 100 * 1000)
|
|
|
|
return -EINVAL;
|
|
|
|
|
|
|
|
priv->scl_irq_data = duration;
|
|
|
|
/*
|
|
|
|
* Interrupt on falling SCL. This ensures that the master under test has
|
|
|
|
* really started the transfer. Interrupt on falling SDA did only
|
|
|
|
* exercise 'bus busy' detection on some HW but not 'arbitration lost'.
|
|
|
|
* Note that the interrupt latency may cause the first bits to be
|
|
|
|
* transmitted correctly.
|
|
|
|
*/
|
|
|
|
return i2c_gpio_fi_act_on_scl_irq(priv, lose_arbitration_irq);
|
|
|
|
}
|
|
|
|
DEFINE_DEBUGFS_ATTRIBUTE(fops_lose_arbitration, NULL, fops_lose_arbitration_set, "%llu\n");
|
|
|
|
|
2019-02-20 00:39:46 +08:00
|
|
|
static irqreturn_t inject_panic_irq(int irq, void *dev_id)
|
|
|
|
{
|
|
|
|
struct i2c_gpio_private_data *priv = dev_id;
|
|
|
|
|
|
|
|
udelay(priv->scl_irq_data);
|
|
|
|
panic("I2C fault injector induced panic");
|
|
|
|
|
|
|
|
return IRQ_HANDLED;
|
|
|
|
}
|
|
|
|
|
|
|
|
static int fops_inject_panic_set(void *data, u64 duration)
|
|
|
|
{
|
|
|
|
struct i2c_gpio_private_data *priv = data;
|
|
|
|
|
|
|
|
if (duration > 100 * 1000)
|
|
|
|
return -EINVAL;
|
|
|
|
|
|
|
|
priv->scl_irq_data = duration;
|
|
|
|
/*
|
|
|
|
* Interrupt on falling SCL. This ensures that the master under test has
|
|
|
|
* really started the transfer.
|
|
|
|
*/
|
|
|
|
return i2c_gpio_fi_act_on_scl_irq(priv, inject_panic_irq);
|
|
|
|
}
|
|
|
|
DEFINE_DEBUGFS_ATTRIBUTE(fops_inject_panic, NULL, fops_inject_panic_set, "%llu\n");
|
|
|
|
|
2017-11-28 23:53:32 +08:00
|
|
|
static void i2c_gpio_fault_injector_init(struct platform_device *pdev)
|
|
|
|
{
|
|
|
|
struct i2c_gpio_private_data *priv = platform_get_drvdata(pdev);
|
|
|
|
|
|
|
|
/*
|
|
|
|
* If there will be a debugfs-dir per i2c adapter somewhen, put the
|
|
|
|
* 'fault-injector' dir there. Until then, we have a global dir with
|
|
|
|
* all adapters as subdirs.
|
|
|
|
*/
|
|
|
|
if (!i2c_gpio_debug_dir) {
|
|
|
|
i2c_gpio_debug_dir = debugfs_create_dir("i2c-fault-injector", NULL);
|
|
|
|
if (!i2c_gpio_debug_dir)
|
|
|
|
return;
|
|
|
|
}
|
|
|
|
|
|
|
|
priv->debug_dir = debugfs_create_dir(pdev->name, i2c_gpio_debug_dir);
|
|
|
|
if (!priv->debug_dir)
|
|
|
|
return;
|
|
|
|
|
2019-02-20 00:39:45 +08:00
|
|
|
init_completion(&priv->scl_irq_completion);
|
|
|
|
|
2018-06-29 17:12:46 +08:00
|
|
|
debugfs_create_file_unsafe("incomplete_address_phase", 0200, priv->debug_dir,
|
|
|
|
priv, &fops_incomplete_addr_phase);
|
2018-06-29 17:12:47 +08:00
|
|
|
debugfs_create_file_unsafe("incomplete_write_byte", 0200, priv->debug_dir,
|
|
|
|
priv, &fops_incomplete_write_byte);
|
2019-02-20 00:39:46 +08:00
|
|
|
if (priv->bit_data.getscl) {
|
|
|
|
debugfs_create_file_unsafe("inject_panic", 0200, priv->debug_dir,
|
|
|
|
priv, &fops_inject_panic);
|
2019-02-20 00:39:45 +08:00
|
|
|
debugfs_create_file_unsafe("lose_arbitration", 0200, priv->debug_dir,
|
|
|
|
priv, &fops_lose_arbitration);
|
2019-02-20 00:39:46 +08:00
|
|
|
}
|
2019-01-21 22:16:56 +08:00
|
|
|
debugfs_create_file_unsafe("scl", 0600, priv->debug_dir, priv, &fops_scl);
|
|
|
|
debugfs_create_file_unsafe("sda", 0600, priv->debug_dir, priv, &fops_sda);
|
2017-11-28 23:53:32 +08:00
|
|
|
}
|
|
|
|
|
|
|
|
static void i2c_gpio_fault_injector_exit(struct platform_device *pdev)
|
|
|
|
{
|
|
|
|
struct i2c_gpio_private_data *priv = platform_get_drvdata(pdev);
|
|
|
|
|
|
|
|
debugfs_remove_recursive(priv->debug_dir);
|
|
|
|
}
|
|
|
|
#else
|
|
|
|
static inline void i2c_gpio_fault_injector_init(struct platform_device *pdev) {}
|
|
|
|
static inline void i2c_gpio_fault_injector_exit(struct platform_device *pdev) {}
|
|
|
|
#endif /* CONFIG_I2C_GPIO_FAULT_INJECTOR*/
|
|
|
|
|
2013-02-28 09:01:40 +08:00
|
|
|
static void of_i2c_gpio_get_props(struct device_node *np,
|
|
|
|
struct i2c_gpio_platform_data *pdata)
|
|
|
|
{
|
|
|
|
u32 reg;
|
|
|
|
|
2012-02-05 18:22:34 +08:00
|
|
|
of_property_read_u32(np, "i2c-gpio,delay-us", &pdata->udelay);
|
|
|
|
|
|
|
|
if (!of_property_read_u32(np, "i2c-gpio,timeout-ms", ®))
|
|
|
|
pdata->timeout = msecs_to_jiffies(reg);
|
|
|
|
|
|
|
|
pdata->sda_is_open_drain =
|
|
|
|
of_property_read_bool(np, "i2c-gpio,sda-open-drain");
|
|
|
|
pdata->scl_is_open_drain =
|
|
|
|
of_property_read_bool(np, "i2c-gpio,scl-open-drain");
|
|
|
|
pdata->scl_is_output_only =
|
|
|
|
of_property_read_bool(np, "i2c-gpio,scl-output-only");
|
|
|
|
}
|
|
|
|
|
2017-09-17 05:56:49 +08:00
|
|
|
static struct gpio_desc *i2c_gpio_get_desc(struct device *dev,
|
|
|
|
const char *con_id,
|
|
|
|
unsigned int index,
|
|
|
|
enum gpiod_flags gflags)
|
|
|
|
{
|
|
|
|
struct gpio_desc *retdesc;
|
|
|
|
int ret;
|
|
|
|
|
|
|
|
retdesc = devm_gpiod_get(dev, con_id, gflags);
|
|
|
|
if (!IS_ERR(retdesc)) {
|
|
|
|
dev_dbg(dev, "got GPIO from name %s\n", con_id);
|
|
|
|
return retdesc;
|
|
|
|
}
|
|
|
|
|
|
|
|
retdesc = devm_gpiod_get_index(dev, NULL, index, gflags);
|
|
|
|
if (!IS_ERR(retdesc)) {
|
|
|
|
dev_dbg(dev, "got GPIO from index %u\n", index);
|
|
|
|
return retdesc;
|
|
|
|
}
|
|
|
|
|
|
|
|
ret = PTR_ERR(retdesc);
|
|
|
|
|
|
|
|
/* FIXME: hack in the old code, is this really necessary? */
|
|
|
|
if (ret == -EINVAL)
|
|
|
|
retdesc = ERR_PTR(-EPROBE_DEFER);
|
|
|
|
|
|
|
|
/* This happens if the GPIO driver is not yet probed, let's defer */
|
|
|
|
if (ret == -ENOENT)
|
|
|
|
retdesc = ERR_PTR(-EPROBE_DEFER);
|
|
|
|
|
|
|
|
if (ret != -EPROBE_DEFER)
|
|
|
|
dev_err(dev, "error trying to get descriptor: %d\n", ret);
|
|
|
|
|
|
|
|
return retdesc;
|
|
|
|
}
|
|
|
|
|
2012-11-28 04:59:38 +08:00
|
|
|
static int i2c_gpio_probe(struct platform_device *pdev)
|
i2c: Bitbanging I2C bus driver using the GPIO API
This is a very simple bitbanging I2C bus driver utilizing the new
arch-neutral GPIO API. Useful for chips that don't have a built-in
I2C controller, additional I2C busses, or testing purposes.
To use, include something similar to the following in the
board-specific setup code:
#include <linux/i2c-gpio.h>
static struct i2c_gpio_platform_data i2c_gpio_data = {
.sda_pin = GPIO_PIN_FOO,
.scl_pin = GPIO_PIN_BAR,
};
static struct platform_device i2c_gpio_device = {
.name = "i2c-gpio",
.id = 0,
.dev = {
.platform_data = &i2c_gpio_data,
},
};
Register this platform_device, set up the I2C pins as GPIO if
required and you're ready to go. This will use default values for
udelay and timeout, and will work with GPIO hardware that does not
support open drain mode, but allows sensing of the SDA and SCL lines
even when they are being driven.
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2007-05-02 05:26:34 +08:00
|
|
|
{
|
2012-02-05 18:22:34 +08:00
|
|
|
struct i2c_gpio_private_data *priv;
|
i2c: Bitbanging I2C bus driver using the GPIO API
This is a very simple bitbanging I2C bus driver utilizing the new
arch-neutral GPIO API. Useful for chips that don't have a built-in
I2C controller, additional I2C busses, or testing purposes.
To use, include something similar to the following in the
board-specific setup code:
#include <linux/i2c-gpio.h>
static struct i2c_gpio_platform_data i2c_gpio_data = {
.sda_pin = GPIO_PIN_FOO,
.scl_pin = GPIO_PIN_BAR,
};
static struct platform_device i2c_gpio_device = {
.name = "i2c-gpio",
.id = 0,
.dev = {
.platform_data = &i2c_gpio_data,
},
};
Register this platform_device, set up the I2C pins as GPIO if
required and you're ready to go. This will use default values for
udelay and timeout, and will work with GPIO hardware that does not
support open drain mode, but allows sensing of the SDA and SCL lines
even when they are being driven.
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2007-05-02 05:26:34 +08:00
|
|
|
struct i2c_gpio_platform_data *pdata;
|
|
|
|
struct i2c_algo_bit_data *bit_data;
|
|
|
|
struct i2c_adapter *adap;
|
2017-09-11 05:15:35 +08:00
|
|
|
struct device *dev = &pdev->dev;
|
|
|
|
struct device_node *np = dev->of_node;
|
2017-09-11 01:54:21 +08:00
|
|
|
enum gpiod_flags gflags;
|
i2c: Bitbanging I2C bus driver using the GPIO API
This is a very simple bitbanging I2C bus driver utilizing the new
arch-neutral GPIO API. Useful for chips that don't have a built-in
I2C controller, additional I2C busses, or testing purposes.
To use, include something similar to the following in the
board-specific setup code:
#include <linux/i2c-gpio.h>
static struct i2c_gpio_platform_data i2c_gpio_data = {
.sda_pin = GPIO_PIN_FOO,
.scl_pin = GPIO_PIN_BAR,
};
static struct platform_device i2c_gpio_device = {
.name = "i2c-gpio",
.id = 0,
.dev = {
.platform_data = &i2c_gpio_data,
},
};
Register this platform_device, set up the I2C pins as GPIO if
required and you're ready to go. This will use default values for
udelay and timeout, and will work with GPIO hardware that does not
support open drain mode, but allows sensing of the SDA and SCL lines
even when they are being driven.
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2007-05-02 05:26:34 +08:00
|
|
|
int ret;
|
|
|
|
|
2017-09-11 05:15:35 +08:00
|
|
|
priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
|
i2c: gpio: Convert to use descriptors
This converts the GPIO-based I2C-driver to using GPIO
descriptors instead of the old global numberspace-based
GPIO interface. We:
- Convert the driver to unconditionally grab two GPIOs
from the device by index 0 (SDA) and 1 (SCL) which
will work fine with device tree and descriptor tables.
The existing device trees will continue to work just
like before, but without any roundtrip through the
global numberspace.
- Brutally convert all boardfiles still passing global
GPIOs by registering descriptor tables associated with
the devices instead so this driver does not need to keep
supporting passing any GPIO numbers as platform data.
There is no stepwise approach as elegant as this, I
strongly prefer this big hammer over any antsteps for this
conversion. This way the old GPIO numbers go away and
NEVER COME BACK.
Special conversion for the different boards utilizing
I2C-GPIO:
- EP93xx (arch/arm/mach-ep93xx): pretty straight forward as
all boards were using the same two GPIO lines, just define
these two in a lookup table for "i2c-gpio" and register
these along with the device. None of them define any
other platform data so just pass NULL as platform data.
This platform selects GPIOLIB so all should be smooth.
The pins appear on a gpiochip for bank "G" as pins 1 (SDA)
and 0 (SCL).
- IXP4 (arch/arm/mach-ixp4): descriptor tables have to
be registered for each board separately. They all use
"IXP4XX_GPIO_CHIP" so it is pretty straight forward.
Most board define no other platform data than SCL/SDA
so they can drop the #include of <linux/i2c-gpio.h> and
assign NULL to platform data.
The "goramo_mlr" (Goramo Multilink Router) board is a bit
worrisome: it implements its own I2C bit-banging in the
board file, and optionally registers an I2C serial port,
but claims the same GPIO lines for itself in the board file.
This is not going to work: there will be competition for the
GPIO lines, so delete the optional extra I2C bus instead, no
I2C devices are registered on it anyway, there are just hints
that it may contain an EEPROM that may be accessed from
userspace. This needs to be fixed up properly by the serial
clock using I2C emulation so drop a note in the code.
- KS8695 board acs5k (arch/arm/mach-ks8695/board-acs5.c)
has some platform data in addition to the pins so it needs to
be kept around sans GPIO lines. Its GPIO chip is named
"KS8695" and the arch selects GPIOLIB.
- PXA boards (arch/arm/mach-pxa/*) use some of the platform
data so it needs to be preserved here. The viper board even
registers two GPIO I2Cs. The gpiochip is named "gpio-pxa" and
the arch selects GPIOLIB.
- SA1100 Simpad (arch/arm/mach-sa1100/simpad.c) defines a GPIO
I2C bus, and the arch selects GPIOLIB.
- Blackfin boards (arch/blackfin/bf533 etc) for these I assume
their I2C GPIOs refer to the local gpiochip defined in
arch/blackfin/kernel/bfin_gpio.c names "BFIN-GPIO".
The arch selects GPIOLIB. The boards get spiked with
IF_ENABLED(I2C_GPIO) but that is a side effect of it
being like that already (I would just have Kconfig select
I2C_GPIO and get rid of them all.) I also delete any
platform data set to 0 as it will get that value anyway
from static declartions of platform data.
- The MIPS selects GPIOLIB and the Alchemy machine is using
two local GPIO chips, one of them has a GPIO I2C. We need
to adjust the local offset from the global number space here.
The ATH79 has a proper GPIO driver in drivers/gpio/gpio-ath79.c
and AFAICT the chip is named "ath79-gpio" and the PB44
PCF857x expander spawns from this on GPIO 1 and 0. The latter
board only use the platform data to specify pins so it can be
cut altogether after this.
- The MFD Silicon Motion SM501 is a special case. It dynamically
spawns an I2C bus off the MFD using sm501_create_subdev().
We use an approach to dynamically create a machine descriptor
table and attach this to the "SM501-LOW" or "SM501-HIGH"
gpiochip. We use chip-local offsets to grab the right lines.
We can get rid of two local static inline helpers as part
of this refactoring.
Cc: Steven Miao <realmz6@gmail.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Magnus Damm <magnus.damm@gmail.com>
Cc: Ben Dooks <ben.dooks@codethink.co.uk>
Cc: Heiko Schocher <hs@denx.de>
Acked-by: Wu, Aaron <Aaron.Wu@analog.com>
Acked-by: Olof Johansson <olof@lixom.net>
Acked-by: Lee Jones <lee.jones@linaro.org>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2017-09-10 07:30:46 +08:00
|
|
|
if (!priv)
|
|
|
|
return -ENOMEM;
|
i2c: Bitbanging I2C bus driver using the GPIO API
This is a very simple bitbanging I2C bus driver utilizing the new
arch-neutral GPIO API. Useful for chips that don't have a built-in
I2C controller, additional I2C busses, or testing purposes.
To use, include something similar to the following in the
board-specific setup code:
#include <linux/i2c-gpio.h>
static struct i2c_gpio_platform_data i2c_gpio_data = {
.sda_pin = GPIO_PIN_FOO,
.scl_pin = GPIO_PIN_BAR,
};
static struct platform_device i2c_gpio_device = {
.name = "i2c-gpio",
.id = 0,
.dev = {
.platform_data = &i2c_gpio_data,
},
};
Register this platform_device, set up the I2C pins as GPIO if
required and you're ready to go. This will use default values for
udelay and timeout, and will work with GPIO hardware that does not
support open drain mode, but allows sensing of the SDA and SCL lines
even when they are being driven.
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2007-05-02 05:26:34 +08:00
|
|
|
|
2013-02-28 09:01:40 +08:00
|
|
|
adap = &priv->adap;
|
|
|
|
bit_data = &priv->bit_data;
|
|
|
|
pdata = &priv->pdata;
|
|
|
|
|
2017-09-11 05:15:35 +08:00
|
|
|
if (np) {
|
|
|
|
of_i2c_gpio_get_props(np, pdata);
|
2013-02-28 09:01:40 +08:00
|
|
|
} else {
|
i2c: gpio: Convert to use descriptors
This converts the GPIO-based I2C-driver to using GPIO
descriptors instead of the old global numberspace-based
GPIO interface. We:
- Convert the driver to unconditionally grab two GPIOs
from the device by index 0 (SDA) and 1 (SCL) which
will work fine with device tree and descriptor tables.
The existing device trees will continue to work just
like before, but without any roundtrip through the
global numberspace.
- Brutally convert all boardfiles still passing global
GPIOs by registering descriptor tables associated with
the devices instead so this driver does not need to keep
supporting passing any GPIO numbers as platform data.
There is no stepwise approach as elegant as this, I
strongly prefer this big hammer over any antsteps for this
conversion. This way the old GPIO numbers go away and
NEVER COME BACK.
Special conversion for the different boards utilizing
I2C-GPIO:
- EP93xx (arch/arm/mach-ep93xx): pretty straight forward as
all boards were using the same two GPIO lines, just define
these two in a lookup table for "i2c-gpio" and register
these along with the device. None of them define any
other platform data so just pass NULL as platform data.
This platform selects GPIOLIB so all should be smooth.
The pins appear on a gpiochip for bank "G" as pins 1 (SDA)
and 0 (SCL).
- IXP4 (arch/arm/mach-ixp4): descriptor tables have to
be registered for each board separately. They all use
"IXP4XX_GPIO_CHIP" so it is pretty straight forward.
Most board define no other platform data than SCL/SDA
so they can drop the #include of <linux/i2c-gpio.h> and
assign NULL to platform data.
The "goramo_mlr" (Goramo Multilink Router) board is a bit
worrisome: it implements its own I2C bit-banging in the
board file, and optionally registers an I2C serial port,
but claims the same GPIO lines for itself in the board file.
This is not going to work: there will be competition for the
GPIO lines, so delete the optional extra I2C bus instead, no
I2C devices are registered on it anyway, there are just hints
that it may contain an EEPROM that may be accessed from
userspace. This needs to be fixed up properly by the serial
clock using I2C emulation so drop a note in the code.
- KS8695 board acs5k (arch/arm/mach-ks8695/board-acs5.c)
has some platform data in addition to the pins so it needs to
be kept around sans GPIO lines. Its GPIO chip is named
"KS8695" and the arch selects GPIOLIB.
- PXA boards (arch/arm/mach-pxa/*) use some of the platform
data so it needs to be preserved here. The viper board even
registers two GPIO I2Cs. The gpiochip is named "gpio-pxa" and
the arch selects GPIOLIB.
- SA1100 Simpad (arch/arm/mach-sa1100/simpad.c) defines a GPIO
I2C bus, and the arch selects GPIOLIB.
- Blackfin boards (arch/blackfin/bf533 etc) for these I assume
their I2C GPIOs refer to the local gpiochip defined in
arch/blackfin/kernel/bfin_gpio.c names "BFIN-GPIO".
The arch selects GPIOLIB. The boards get spiked with
IF_ENABLED(I2C_GPIO) but that is a side effect of it
being like that already (I would just have Kconfig select
I2C_GPIO and get rid of them all.) I also delete any
platform data set to 0 as it will get that value anyway
from static declartions of platform data.
- The MIPS selects GPIOLIB and the Alchemy machine is using
two local GPIO chips, one of them has a GPIO I2C. We need
to adjust the local offset from the global number space here.
The ATH79 has a proper GPIO driver in drivers/gpio/gpio-ath79.c
and AFAICT the chip is named "ath79-gpio" and the PB44
PCF857x expander spawns from this on GPIO 1 and 0. The latter
board only use the platform data to specify pins so it can be
cut altogether after this.
- The MFD Silicon Motion SM501 is a special case. It dynamically
spawns an I2C bus off the MFD using sm501_create_subdev().
We use an approach to dynamically create a machine descriptor
table and attach this to the "SM501-LOW" or "SM501-HIGH"
gpiochip. We use chip-local offsets to grab the right lines.
We can get rid of two local static inline helpers as part
of this refactoring.
Cc: Steven Miao <realmz6@gmail.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Magnus Damm <magnus.damm@gmail.com>
Cc: Ben Dooks <ben.dooks@codethink.co.uk>
Cc: Heiko Schocher <hs@denx.de>
Acked-by: Wu, Aaron <Aaron.Wu@analog.com>
Acked-by: Olof Johansson <olof@lixom.net>
Acked-by: Lee Jones <lee.jones@linaro.org>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2017-09-10 07:30:46 +08:00
|
|
|
/*
|
|
|
|
* If all platform data settings are zero it is OK
|
|
|
|
* to not provide any platform data from the board.
|
|
|
|
*/
|
2017-09-11 05:15:35 +08:00
|
|
|
if (dev_get_platdata(dev))
|
|
|
|
memcpy(pdata, dev_get_platdata(dev), sizeof(*pdata));
|
2013-02-28 09:01:40 +08:00
|
|
|
}
|
i2c: Bitbanging I2C bus driver using the GPIO API
This is a very simple bitbanging I2C bus driver utilizing the new
arch-neutral GPIO API. Useful for chips that don't have a built-in
I2C controller, additional I2C busses, or testing purposes.
To use, include something similar to the following in the
board-specific setup code:
#include <linux/i2c-gpio.h>
static struct i2c_gpio_platform_data i2c_gpio_data = {
.sda_pin = GPIO_PIN_FOO,
.scl_pin = GPIO_PIN_BAR,
};
static struct platform_device i2c_gpio_device = {
.name = "i2c-gpio",
.id = 0,
.dev = {
.platform_data = &i2c_gpio_data,
},
};
Register this platform_device, set up the I2C pins as GPIO if
required and you're ready to go. This will use default values for
udelay and timeout, and will work with GPIO hardware that does not
support open drain mode, but allows sensing of the SDA and SCL lines
even when they are being driven.
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2007-05-02 05:26:34 +08:00
|
|
|
|
i2c: gpio: Convert to use descriptors
This converts the GPIO-based I2C-driver to using GPIO
descriptors instead of the old global numberspace-based
GPIO interface. We:
- Convert the driver to unconditionally grab two GPIOs
from the device by index 0 (SDA) and 1 (SCL) which
will work fine with device tree and descriptor tables.
The existing device trees will continue to work just
like before, but without any roundtrip through the
global numberspace.
- Brutally convert all boardfiles still passing global
GPIOs by registering descriptor tables associated with
the devices instead so this driver does not need to keep
supporting passing any GPIO numbers as platform data.
There is no stepwise approach as elegant as this, I
strongly prefer this big hammer over any antsteps for this
conversion. This way the old GPIO numbers go away and
NEVER COME BACK.
Special conversion for the different boards utilizing
I2C-GPIO:
- EP93xx (arch/arm/mach-ep93xx): pretty straight forward as
all boards were using the same two GPIO lines, just define
these two in a lookup table for "i2c-gpio" and register
these along with the device. None of them define any
other platform data so just pass NULL as platform data.
This platform selects GPIOLIB so all should be smooth.
The pins appear on a gpiochip for bank "G" as pins 1 (SDA)
and 0 (SCL).
- IXP4 (arch/arm/mach-ixp4): descriptor tables have to
be registered for each board separately. They all use
"IXP4XX_GPIO_CHIP" so it is pretty straight forward.
Most board define no other platform data than SCL/SDA
so they can drop the #include of <linux/i2c-gpio.h> and
assign NULL to platform data.
The "goramo_mlr" (Goramo Multilink Router) board is a bit
worrisome: it implements its own I2C bit-banging in the
board file, and optionally registers an I2C serial port,
but claims the same GPIO lines for itself in the board file.
This is not going to work: there will be competition for the
GPIO lines, so delete the optional extra I2C bus instead, no
I2C devices are registered on it anyway, there are just hints
that it may contain an EEPROM that may be accessed from
userspace. This needs to be fixed up properly by the serial
clock using I2C emulation so drop a note in the code.
- KS8695 board acs5k (arch/arm/mach-ks8695/board-acs5.c)
has some platform data in addition to the pins so it needs to
be kept around sans GPIO lines. Its GPIO chip is named
"KS8695" and the arch selects GPIOLIB.
- PXA boards (arch/arm/mach-pxa/*) use some of the platform
data so it needs to be preserved here. The viper board even
registers two GPIO I2Cs. The gpiochip is named "gpio-pxa" and
the arch selects GPIOLIB.
- SA1100 Simpad (arch/arm/mach-sa1100/simpad.c) defines a GPIO
I2C bus, and the arch selects GPIOLIB.
- Blackfin boards (arch/blackfin/bf533 etc) for these I assume
their I2C GPIOs refer to the local gpiochip defined in
arch/blackfin/kernel/bfin_gpio.c names "BFIN-GPIO".
The arch selects GPIOLIB. The boards get spiked with
IF_ENABLED(I2C_GPIO) but that is a side effect of it
being like that already (I would just have Kconfig select
I2C_GPIO and get rid of them all.) I also delete any
platform data set to 0 as it will get that value anyway
from static declartions of platform data.
- The MIPS selects GPIOLIB and the Alchemy machine is using
two local GPIO chips, one of them has a GPIO I2C. We need
to adjust the local offset from the global number space here.
The ATH79 has a proper GPIO driver in drivers/gpio/gpio-ath79.c
and AFAICT the chip is named "ath79-gpio" and the PB44
PCF857x expander spawns from this on GPIO 1 and 0. The latter
board only use the platform data to specify pins so it can be
cut altogether after this.
- The MFD Silicon Motion SM501 is a special case. It dynamically
spawns an I2C bus off the MFD using sm501_create_subdev().
We use an approach to dynamically create a machine descriptor
table and attach this to the "SM501-LOW" or "SM501-HIGH"
gpiochip. We use chip-local offsets to grab the right lines.
We can get rid of two local static inline helpers as part
of this refactoring.
Cc: Steven Miao <realmz6@gmail.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Magnus Damm <magnus.damm@gmail.com>
Cc: Ben Dooks <ben.dooks@codethink.co.uk>
Cc: Heiko Schocher <hs@denx.de>
Acked-by: Wu, Aaron <Aaron.Wu@analog.com>
Acked-by: Olof Johansson <olof@lixom.net>
Acked-by: Lee Jones <lee.jones@linaro.org>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2017-09-10 07:30:46 +08:00
|
|
|
/*
|
2017-09-11 01:54:21 +08:00
|
|
|
* First get the GPIO pins; if it fails, we'll defer the probe.
|
2019-02-05 20:58:41 +08:00
|
|
|
* If the SCL/SDA lines are marked "open drain" by platform data or
|
|
|
|
* device tree then this means that something outside of our control is
|
|
|
|
* marking these lines to be handled as open drain, and we should just
|
|
|
|
* handle them as we handle any other output. Else we enforce open
|
|
|
|
* drain as this is required for an I2C bus.
|
i2c: gpio: Convert to use descriptors
This converts the GPIO-based I2C-driver to using GPIO
descriptors instead of the old global numberspace-based
GPIO interface. We:
- Convert the driver to unconditionally grab two GPIOs
from the device by index 0 (SDA) and 1 (SCL) which
will work fine with device tree and descriptor tables.
The existing device trees will continue to work just
like before, but without any roundtrip through the
global numberspace.
- Brutally convert all boardfiles still passing global
GPIOs by registering descriptor tables associated with
the devices instead so this driver does not need to keep
supporting passing any GPIO numbers as platform data.
There is no stepwise approach as elegant as this, I
strongly prefer this big hammer over any antsteps for this
conversion. This way the old GPIO numbers go away and
NEVER COME BACK.
Special conversion for the different boards utilizing
I2C-GPIO:
- EP93xx (arch/arm/mach-ep93xx): pretty straight forward as
all boards were using the same two GPIO lines, just define
these two in a lookup table for "i2c-gpio" and register
these along with the device. None of them define any
other platform data so just pass NULL as platform data.
This platform selects GPIOLIB so all should be smooth.
The pins appear on a gpiochip for bank "G" as pins 1 (SDA)
and 0 (SCL).
- IXP4 (arch/arm/mach-ixp4): descriptor tables have to
be registered for each board separately. They all use
"IXP4XX_GPIO_CHIP" so it is pretty straight forward.
Most board define no other platform data than SCL/SDA
so they can drop the #include of <linux/i2c-gpio.h> and
assign NULL to platform data.
The "goramo_mlr" (Goramo Multilink Router) board is a bit
worrisome: it implements its own I2C bit-banging in the
board file, and optionally registers an I2C serial port,
but claims the same GPIO lines for itself in the board file.
This is not going to work: there will be competition for the
GPIO lines, so delete the optional extra I2C bus instead, no
I2C devices are registered on it anyway, there are just hints
that it may contain an EEPROM that may be accessed from
userspace. This needs to be fixed up properly by the serial
clock using I2C emulation so drop a note in the code.
- KS8695 board acs5k (arch/arm/mach-ks8695/board-acs5.c)
has some platform data in addition to the pins so it needs to
be kept around sans GPIO lines. Its GPIO chip is named
"KS8695" and the arch selects GPIOLIB.
- PXA boards (arch/arm/mach-pxa/*) use some of the platform
data so it needs to be preserved here. The viper board even
registers two GPIO I2Cs. The gpiochip is named "gpio-pxa" and
the arch selects GPIOLIB.
- SA1100 Simpad (arch/arm/mach-sa1100/simpad.c) defines a GPIO
I2C bus, and the arch selects GPIOLIB.
- Blackfin boards (arch/blackfin/bf533 etc) for these I assume
their I2C GPIOs refer to the local gpiochip defined in
arch/blackfin/kernel/bfin_gpio.c names "BFIN-GPIO".
The arch selects GPIOLIB. The boards get spiked with
IF_ENABLED(I2C_GPIO) but that is a side effect of it
being like that already (I would just have Kconfig select
I2C_GPIO and get rid of them all.) I also delete any
platform data set to 0 as it will get that value anyway
from static declartions of platform data.
- The MIPS selects GPIOLIB and the Alchemy machine is using
two local GPIO chips, one of them has a GPIO I2C. We need
to adjust the local offset from the global number space here.
The ATH79 has a proper GPIO driver in drivers/gpio/gpio-ath79.c
and AFAICT the chip is named "ath79-gpio" and the PB44
PCF857x expander spawns from this on GPIO 1 and 0. The latter
board only use the platform data to specify pins so it can be
cut altogether after this.
- The MFD Silicon Motion SM501 is a special case. It dynamically
spawns an I2C bus off the MFD using sm501_create_subdev().
We use an approach to dynamically create a machine descriptor
table and attach this to the "SM501-LOW" or "SM501-HIGH"
gpiochip. We use chip-local offsets to grab the right lines.
We can get rid of two local static inline helpers as part
of this refactoring.
Cc: Steven Miao <realmz6@gmail.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Magnus Damm <magnus.damm@gmail.com>
Cc: Ben Dooks <ben.dooks@codethink.co.uk>
Cc: Heiko Schocher <hs@denx.de>
Acked-by: Wu, Aaron <Aaron.Wu@analog.com>
Acked-by: Olof Johansson <olof@lixom.net>
Acked-by: Lee Jones <lee.jones@linaro.org>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2017-09-10 07:30:46 +08:00
|
|
|
*/
|
2017-09-11 01:54:21 +08:00
|
|
|
if (pdata->sda_is_open_drain)
|
|
|
|
gflags = GPIOD_OUT_HIGH;
|
|
|
|
else
|
|
|
|
gflags = GPIOD_OUT_HIGH_OPEN_DRAIN;
|
2017-09-17 05:56:49 +08:00
|
|
|
priv->sda = i2c_gpio_get_desc(dev, "sda", 0, gflags);
|
|
|
|
if (IS_ERR(priv->sda))
|
|
|
|
return PTR_ERR(priv->sda);
|
|
|
|
|
2017-09-11 01:54:21 +08:00
|
|
|
if (pdata->scl_is_open_drain)
|
2018-06-16 20:56:36 +08:00
|
|
|
gflags = GPIOD_OUT_HIGH;
|
2017-09-11 01:54:21 +08:00
|
|
|
else
|
2018-06-16 20:56:36 +08:00
|
|
|
gflags = GPIOD_OUT_HIGH_OPEN_DRAIN;
|
2017-09-17 05:56:49 +08:00
|
|
|
priv->scl = i2c_gpio_get_desc(dev, "scl", 1, gflags);
|
|
|
|
if (IS_ERR(priv->scl))
|
|
|
|
return PTR_ERR(priv->scl);
|
i2c: Bitbanging I2C bus driver using the GPIO API
This is a very simple bitbanging I2C bus driver utilizing the new
arch-neutral GPIO API. Useful for chips that don't have a built-in
I2C controller, additional I2C busses, or testing purposes.
To use, include something similar to the following in the
board-specific setup code:
#include <linux/i2c-gpio.h>
static struct i2c_gpio_platform_data i2c_gpio_data = {
.sda_pin = GPIO_PIN_FOO,
.scl_pin = GPIO_PIN_BAR,
};
static struct platform_device i2c_gpio_device = {
.name = "i2c-gpio",
.id = 0,
.dev = {
.platform_data = &i2c_gpio_data,
},
};
Register this platform_device, set up the I2C pins as GPIO if
required and you're ready to go. This will use default values for
udelay and timeout, and will work with GPIO hardware that does not
support open drain mode, but allows sensing of the SDA and SCL lines
even when they are being driven.
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2007-05-02 05:26:34 +08:00
|
|
|
|
i2c: gpio: Enable working over slow can_sleep GPIOs
"Slow" GPIOs (usually those connected over an SPI or an I2C bus) are,
well, slow in their operation. It is generally a good idea to avoid
using them for time-critical operation, but sometimes the hardware just
sucks, and the software has to cope. In addition to that, the I2C bus
itself does not actually define any strict timing limits; the bus is
free to go all the way down to DC. The timeouts (and therefore the
slowest acceptable frequency) are present only in SMBus.
The `can_sleep` is IMHO a wrong concept to use here. My SPI-to-quad-UART
chip (MAX14830) is connected via a 26MHz SPI bus, and it happily drives
SCL at 200kHz (5µs pulses) during my benchmarks. That's faster than the
maximal allowed speed of the traditional I2C.
The previous version of this code did not really block operation over
slow GPIO pins, anyway. Instead, it just resorted to printing a warning
with a backtrace each time a GPIO pin was accessed, thereby slowing
things down even more.
Finally, it's not just me. A similar patch was originally submitted in
2015 [1].
[1] https://patchwork.ozlabs.org/patch/450956/
Signed-off-by: Jan Kundrát <jan.kundrat@cesnet.cz>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2017-12-23 05:47:16 +08:00
|
|
|
if (gpiod_cansleep(priv->sda) || gpiod_cansleep(priv->scl))
|
|
|
|
dev_warn(dev, "Slow GPIO pins might wreak havoc into I2C/SMBus bus timing");
|
2019-04-03 20:40:19 +08:00
|
|
|
else
|
|
|
|
bit_data->can_do_atomic = true;
|
i2c: gpio: Enable working over slow can_sleep GPIOs
"Slow" GPIOs (usually those connected over an SPI or an I2C bus) are,
well, slow in their operation. It is generally a good idea to avoid
using them for time-critical operation, but sometimes the hardware just
sucks, and the software has to cope. In addition to that, the I2C bus
itself does not actually define any strict timing limits; the bus is
free to go all the way down to DC. The timeouts (and therefore the
slowest acceptable frequency) are present only in SMBus.
The `can_sleep` is IMHO a wrong concept to use here. My SPI-to-quad-UART
chip (MAX14830) is connected via a 26MHz SPI bus, and it happily drives
SCL at 200kHz (5µs pulses) during my benchmarks. That's faster than the
maximal allowed speed of the traditional I2C.
The previous version of this code did not really block operation over
slow GPIO pins, anyway. Instead, it just resorted to printing a warning
with a backtrace each time a GPIO pin was accessed, thereby slowing
things down even more.
Finally, it's not just me. A similar patch was originally submitted in
2015 [1].
[1] https://patchwork.ozlabs.org/patch/450956/
Signed-off-by: Jan Kundrát <jan.kundrat@cesnet.cz>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2017-12-23 05:47:16 +08:00
|
|
|
|
2017-09-11 01:54:21 +08:00
|
|
|
bit_data->setsda = i2c_gpio_setsda_val;
|
|
|
|
bit_data->setscl = i2c_gpio_setscl_val;
|
|
|
|
|
i2c: Bitbanging I2C bus driver using the GPIO API
This is a very simple bitbanging I2C bus driver utilizing the new
arch-neutral GPIO API. Useful for chips that don't have a built-in
I2C controller, additional I2C busses, or testing purposes.
To use, include something similar to the following in the
board-specific setup code:
#include <linux/i2c-gpio.h>
static struct i2c_gpio_platform_data i2c_gpio_data = {
.sda_pin = GPIO_PIN_FOO,
.scl_pin = GPIO_PIN_BAR,
};
static struct platform_device i2c_gpio_device = {
.name = "i2c-gpio",
.id = 0,
.dev = {
.platform_data = &i2c_gpio_data,
},
};
Register this platform_device, set up the I2C pins as GPIO if
required and you're ready to go. This will use default values for
udelay and timeout, and will work with GPIO hardware that does not
support open drain mode, but allows sensing of the SDA and SCL lines
even when they are being driven.
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2007-05-02 05:26:34 +08:00
|
|
|
if (!pdata->scl_is_output_only)
|
|
|
|
bit_data->getscl = i2c_gpio_getscl;
|
|
|
|
bit_data->getsda = i2c_gpio_getsda;
|
|
|
|
|
|
|
|
if (pdata->udelay)
|
|
|
|
bit_data->udelay = pdata->udelay;
|
|
|
|
else if (pdata->scl_is_output_only)
|
|
|
|
bit_data->udelay = 50; /* 10 kHz */
|
|
|
|
else
|
|
|
|
bit_data->udelay = 5; /* 100 kHz */
|
|
|
|
|
|
|
|
if (pdata->timeout)
|
|
|
|
bit_data->timeout = pdata->timeout;
|
|
|
|
else
|
|
|
|
bit_data->timeout = HZ / 10; /* 100 ms */
|
|
|
|
|
i2c: gpio: Convert to use descriptors
This converts the GPIO-based I2C-driver to using GPIO
descriptors instead of the old global numberspace-based
GPIO interface. We:
- Convert the driver to unconditionally grab two GPIOs
from the device by index 0 (SDA) and 1 (SCL) which
will work fine with device tree and descriptor tables.
The existing device trees will continue to work just
like before, but without any roundtrip through the
global numberspace.
- Brutally convert all boardfiles still passing global
GPIOs by registering descriptor tables associated with
the devices instead so this driver does not need to keep
supporting passing any GPIO numbers as platform data.
There is no stepwise approach as elegant as this, I
strongly prefer this big hammer over any antsteps for this
conversion. This way the old GPIO numbers go away and
NEVER COME BACK.
Special conversion for the different boards utilizing
I2C-GPIO:
- EP93xx (arch/arm/mach-ep93xx): pretty straight forward as
all boards were using the same two GPIO lines, just define
these two in a lookup table for "i2c-gpio" and register
these along with the device. None of them define any
other platform data so just pass NULL as platform data.
This platform selects GPIOLIB so all should be smooth.
The pins appear on a gpiochip for bank "G" as pins 1 (SDA)
and 0 (SCL).
- IXP4 (arch/arm/mach-ixp4): descriptor tables have to
be registered for each board separately. They all use
"IXP4XX_GPIO_CHIP" so it is pretty straight forward.
Most board define no other platform data than SCL/SDA
so they can drop the #include of <linux/i2c-gpio.h> and
assign NULL to platform data.
The "goramo_mlr" (Goramo Multilink Router) board is a bit
worrisome: it implements its own I2C bit-banging in the
board file, and optionally registers an I2C serial port,
but claims the same GPIO lines for itself in the board file.
This is not going to work: there will be competition for the
GPIO lines, so delete the optional extra I2C bus instead, no
I2C devices are registered on it anyway, there are just hints
that it may contain an EEPROM that may be accessed from
userspace. This needs to be fixed up properly by the serial
clock using I2C emulation so drop a note in the code.
- KS8695 board acs5k (arch/arm/mach-ks8695/board-acs5.c)
has some platform data in addition to the pins so it needs to
be kept around sans GPIO lines. Its GPIO chip is named
"KS8695" and the arch selects GPIOLIB.
- PXA boards (arch/arm/mach-pxa/*) use some of the platform
data so it needs to be preserved here. The viper board even
registers two GPIO I2Cs. The gpiochip is named "gpio-pxa" and
the arch selects GPIOLIB.
- SA1100 Simpad (arch/arm/mach-sa1100/simpad.c) defines a GPIO
I2C bus, and the arch selects GPIOLIB.
- Blackfin boards (arch/blackfin/bf533 etc) for these I assume
their I2C GPIOs refer to the local gpiochip defined in
arch/blackfin/kernel/bfin_gpio.c names "BFIN-GPIO".
The arch selects GPIOLIB. The boards get spiked with
IF_ENABLED(I2C_GPIO) but that is a side effect of it
being like that already (I would just have Kconfig select
I2C_GPIO and get rid of them all.) I also delete any
platform data set to 0 as it will get that value anyway
from static declartions of platform data.
- The MIPS selects GPIOLIB and the Alchemy machine is using
two local GPIO chips, one of them has a GPIO I2C. We need
to adjust the local offset from the global number space here.
The ATH79 has a proper GPIO driver in drivers/gpio/gpio-ath79.c
and AFAICT the chip is named "ath79-gpio" and the PB44
PCF857x expander spawns from this on GPIO 1 and 0. The latter
board only use the platform data to specify pins so it can be
cut altogether after this.
- The MFD Silicon Motion SM501 is a special case. It dynamically
spawns an I2C bus off the MFD using sm501_create_subdev().
We use an approach to dynamically create a machine descriptor
table and attach this to the "SM501-LOW" or "SM501-HIGH"
gpiochip. We use chip-local offsets to grab the right lines.
We can get rid of two local static inline helpers as part
of this refactoring.
Cc: Steven Miao <realmz6@gmail.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Magnus Damm <magnus.damm@gmail.com>
Cc: Ben Dooks <ben.dooks@codethink.co.uk>
Cc: Heiko Schocher <hs@denx.de>
Acked-by: Wu, Aaron <Aaron.Wu@analog.com>
Acked-by: Olof Johansson <olof@lixom.net>
Acked-by: Lee Jones <lee.jones@linaro.org>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2017-09-10 07:30:46 +08:00
|
|
|
bit_data->data = priv;
|
i2c: Bitbanging I2C bus driver using the GPIO API
This is a very simple bitbanging I2C bus driver utilizing the new
arch-neutral GPIO API. Useful for chips that don't have a built-in
I2C controller, additional I2C busses, or testing purposes.
To use, include something similar to the following in the
board-specific setup code:
#include <linux/i2c-gpio.h>
static struct i2c_gpio_platform_data i2c_gpio_data = {
.sda_pin = GPIO_PIN_FOO,
.scl_pin = GPIO_PIN_BAR,
};
static struct platform_device i2c_gpio_device = {
.name = "i2c-gpio",
.id = 0,
.dev = {
.platform_data = &i2c_gpio_data,
},
};
Register this platform_device, set up the I2C pins as GPIO if
required and you're ready to go. This will use default values for
udelay and timeout, and will work with GPIO hardware that does not
support open drain mode, but allows sensing of the SDA and SCL lines
even when they are being driven.
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2007-05-02 05:26:34 +08:00
|
|
|
|
|
|
|
adap->owner = THIS_MODULE;
|
2017-09-11 05:15:35 +08:00
|
|
|
if (np)
|
|
|
|
strlcpy(adap->name, dev_name(dev), sizeof(adap->name));
|
2012-10-15 15:51:17 +08:00
|
|
|
else
|
|
|
|
snprintf(adap->name, sizeof(adap->name), "i2c-gpio%d", pdev->id);
|
|
|
|
|
i2c: Bitbanging I2C bus driver using the GPIO API
This is a very simple bitbanging I2C bus driver utilizing the new
arch-neutral GPIO API. Useful for chips that don't have a built-in
I2C controller, additional I2C busses, or testing purposes.
To use, include something similar to the following in the
board-specific setup code:
#include <linux/i2c-gpio.h>
static struct i2c_gpio_platform_data i2c_gpio_data = {
.sda_pin = GPIO_PIN_FOO,
.scl_pin = GPIO_PIN_BAR,
};
static struct platform_device i2c_gpio_device = {
.name = "i2c-gpio",
.id = 0,
.dev = {
.platform_data = &i2c_gpio_data,
},
};
Register this platform_device, set up the I2C pins as GPIO if
required and you're ready to go. This will use default values for
udelay and timeout, and will work with GPIO hardware that does not
support open drain mode, but allows sensing of the SDA and SCL lines
even when they are being driven.
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2007-05-02 05:26:34 +08:00
|
|
|
adap->algo_data = bit_data;
|
2008-07-15 04:38:29 +08:00
|
|
|
adap->class = I2C_CLASS_HWMON | I2C_CLASS_SPD;
|
2017-09-11 05:15:35 +08:00
|
|
|
adap->dev.parent = dev;
|
|
|
|
adap->dev.of_node = np;
|
i2c: Bitbanging I2C bus driver using the GPIO API
This is a very simple bitbanging I2C bus driver utilizing the new
arch-neutral GPIO API. Useful for chips that don't have a built-in
I2C controller, additional I2C busses, or testing purposes.
To use, include something similar to the following in the
board-specific setup code:
#include <linux/i2c-gpio.h>
static struct i2c_gpio_platform_data i2c_gpio_data = {
.sda_pin = GPIO_PIN_FOO,
.scl_pin = GPIO_PIN_BAR,
};
static struct platform_device i2c_gpio_device = {
.name = "i2c-gpio",
.id = 0,
.dev = {
.platform_data = &i2c_gpio_data,
},
};
Register this platform_device, set up the I2C pins as GPIO if
required and you're ready to go. This will use default values for
udelay and timeout, and will work with GPIO hardware that does not
support open drain mode, but allows sensing of the SDA and SCL lines
even when they are being driven.
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2007-05-02 05:26:34 +08:00
|
|
|
|
2012-03-27 17:10:28 +08:00
|
|
|
adap->nr = pdev->id;
|
2007-07-12 20:12:30 +08:00
|
|
|
ret = i2c_bit_add_numbered_bus(adap);
|
i2c: Bitbanging I2C bus driver using the GPIO API
This is a very simple bitbanging I2C bus driver utilizing the new
arch-neutral GPIO API. Useful for chips that don't have a built-in
I2C controller, additional I2C busses, or testing purposes.
To use, include something similar to the following in the
board-specific setup code:
#include <linux/i2c-gpio.h>
static struct i2c_gpio_platform_data i2c_gpio_data = {
.sda_pin = GPIO_PIN_FOO,
.scl_pin = GPIO_PIN_BAR,
};
static struct platform_device i2c_gpio_device = {
.name = "i2c-gpio",
.id = 0,
.dev = {
.platform_data = &i2c_gpio_data,
},
};
Register this platform_device, set up the I2C pins as GPIO if
required and you're ready to go. This will use default values for
udelay and timeout, and will work with GPIO hardware that does not
support open drain mode, but allows sensing of the SDA and SCL lines
even when they are being driven.
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2007-05-02 05:26:34 +08:00
|
|
|
if (ret)
|
2013-12-17 14:48:19 +08:00
|
|
|
return ret;
|
i2c: Bitbanging I2C bus driver using the GPIO API
This is a very simple bitbanging I2C bus driver utilizing the new
arch-neutral GPIO API. Useful for chips that don't have a built-in
I2C controller, additional I2C busses, or testing purposes.
To use, include something similar to the following in the
board-specific setup code:
#include <linux/i2c-gpio.h>
static struct i2c_gpio_platform_data i2c_gpio_data = {
.sda_pin = GPIO_PIN_FOO,
.scl_pin = GPIO_PIN_BAR,
};
static struct platform_device i2c_gpio_device = {
.name = "i2c-gpio",
.id = 0,
.dev = {
.platform_data = &i2c_gpio_data,
},
};
Register this platform_device, set up the I2C pins as GPIO if
required and you're ready to go. This will use default values for
udelay and timeout, and will work with GPIO hardware that does not
support open drain mode, but allows sensing of the SDA and SCL lines
even when they are being driven.
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2007-05-02 05:26:34 +08:00
|
|
|
|
2012-02-05 18:22:34 +08:00
|
|
|
platform_set_drvdata(pdev, priv);
|
i2c: Bitbanging I2C bus driver using the GPIO API
This is a very simple bitbanging I2C bus driver utilizing the new
arch-neutral GPIO API. Useful for chips that don't have a built-in
I2C controller, additional I2C busses, or testing purposes.
To use, include something similar to the following in the
board-specific setup code:
#include <linux/i2c-gpio.h>
static struct i2c_gpio_platform_data i2c_gpio_data = {
.sda_pin = GPIO_PIN_FOO,
.scl_pin = GPIO_PIN_BAR,
};
static struct platform_device i2c_gpio_device = {
.name = "i2c-gpio",
.id = 0,
.dev = {
.platform_data = &i2c_gpio_data,
},
};
Register this platform_device, set up the I2C pins as GPIO if
required and you're ready to go. This will use default values for
udelay and timeout, and will work with GPIO hardware that does not
support open drain mode, but allows sensing of the SDA and SCL lines
even when they are being driven.
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2007-05-02 05:26:34 +08:00
|
|
|
|
i2c: gpio: Convert to use descriptors
This converts the GPIO-based I2C-driver to using GPIO
descriptors instead of the old global numberspace-based
GPIO interface. We:
- Convert the driver to unconditionally grab two GPIOs
from the device by index 0 (SDA) and 1 (SCL) which
will work fine with device tree and descriptor tables.
The existing device trees will continue to work just
like before, but without any roundtrip through the
global numberspace.
- Brutally convert all boardfiles still passing global
GPIOs by registering descriptor tables associated with
the devices instead so this driver does not need to keep
supporting passing any GPIO numbers as platform data.
There is no stepwise approach as elegant as this, I
strongly prefer this big hammer over any antsteps for this
conversion. This way the old GPIO numbers go away and
NEVER COME BACK.
Special conversion for the different boards utilizing
I2C-GPIO:
- EP93xx (arch/arm/mach-ep93xx): pretty straight forward as
all boards were using the same two GPIO lines, just define
these two in a lookup table for "i2c-gpio" and register
these along with the device. None of them define any
other platform data so just pass NULL as platform data.
This platform selects GPIOLIB so all should be smooth.
The pins appear on a gpiochip for bank "G" as pins 1 (SDA)
and 0 (SCL).
- IXP4 (arch/arm/mach-ixp4): descriptor tables have to
be registered for each board separately. They all use
"IXP4XX_GPIO_CHIP" so it is pretty straight forward.
Most board define no other platform data than SCL/SDA
so they can drop the #include of <linux/i2c-gpio.h> and
assign NULL to platform data.
The "goramo_mlr" (Goramo Multilink Router) board is a bit
worrisome: it implements its own I2C bit-banging in the
board file, and optionally registers an I2C serial port,
but claims the same GPIO lines for itself in the board file.
This is not going to work: there will be competition for the
GPIO lines, so delete the optional extra I2C bus instead, no
I2C devices are registered on it anyway, there are just hints
that it may contain an EEPROM that may be accessed from
userspace. This needs to be fixed up properly by the serial
clock using I2C emulation so drop a note in the code.
- KS8695 board acs5k (arch/arm/mach-ks8695/board-acs5.c)
has some platform data in addition to the pins so it needs to
be kept around sans GPIO lines. Its GPIO chip is named
"KS8695" and the arch selects GPIOLIB.
- PXA boards (arch/arm/mach-pxa/*) use some of the platform
data so it needs to be preserved here. The viper board even
registers two GPIO I2Cs. The gpiochip is named "gpio-pxa" and
the arch selects GPIOLIB.
- SA1100 Simpad (arch/arm/mach-sa1100/simpad.c) defines a GPIO
I2C bus, and the arch selects GPIOLIB.
- Blackfin boards (arch/blackfin/bf533 etc) for these I assume
their I2C GPIOs refer to the local gpiochip defined in
arch/blackfin/kernel/bfin_gpio.c names "BFIN-GPIO".
The arch selects GPIOLIB. The boards get spiked with
IF_ENABLED(I2C_GPIO) but that is a side effect of it
being like that already (I would just have Kconfig select
I2C_GPIO and get rid of them all.) I also delete any
platform data set to 0 as it will get that value anyway
from static declartions of platform data.
- The MIPS selects GPIOLIB and the Alchemy machine is using
two local GPIO chips, one of them has a GPIO I2C. We need
to adjust the local offset from the global number space here.
The ATH79 has a proper GPIO driver in drivers/gpio/gpio-ath79.c
and AFAICT the chip is named "ath79-gpio" and the PB44
PCF857x expander spawns from this on GPIO 1 and 0. The latter
board only use the platform data to specify pins so it can be
cut altogether after this.
- The MFD Silicon Motion SM501 is a special case. It dynamically
spawns an I2C bus off the MFD using sm501_create_subdev().
We use an approach to dynamically create a machine descriptor
table and attach this to the "SM501-LOW" or "SM501-HIGH"
gpiochip. We use chip-local offsets to grab the right lines.
We can get rid of two local static inline helpers as part
of this refactoring.
Cc: Steven Miao <realmz6@gmail.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Magnus Damm <magnus.damm@gmail.com>
Cc: Ben Dooks <ben.dooks@codethink.co.uk>
Cc: Heiko Schocher <hs@denx.de>
Acked-by: Wu, Aaron <Aaron.Wu@analog.com>
Acked-by: Olof Johansson <olof@lixom.net>
Acked-by: Lee Jones <lee.jones@linaro.org>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2017-09-10 07:30:46 +08:00
|
|
|
/*
|
|
|
|
* FIXME: using global GPIO numbers is not helpful. If/when we
|
|
|
|
* get accessors to get the actual name of the GPIO line,
|
|
|
|
* from the descriptor, then provide that instead.
|
|
|
|
*/
|
2017-09-11 05:15:35 +08:00
|
|
|
dev_info(dev, "using lines %u (SDA) and %u (SCL%s)\n",
|
i2c: gpio: Convert to use descriptors
This converts the GPIO-based I2C-driver to using GPIO
descriptors instead of the old global numberspace-based
GPIO interface. We:
- Convert the driver to unconditionally grab two GPIOs
from the device by index 0 (SDA) and 1 (SCL) which
will work fine with device tree and descriptor tables.
The existing device trees will continue to work just
like before, but without any roundtrip through the
global numberspace.
- Brutally convert all boardfiles still passing global
GPIOs by registering descriptor tables associated with
the devices instead so this driver does not need to keep
supporting passing any GPIO numbers as platform data.
There is no stepwise approach as elegant as this, I
strongly prefer this big hammer over any antsteps for this
conversion. This way the old GPIO numbers go away and
NEVER COME BACK.
Special conversion for the different boards utilizing
I2C-GPIO:
- EP93xx (arch/arm/mach-ep93xx): pretty straight forward as
all boards were using the same two GPIO lines, just define
these two in a lookup table for "i2c-gpio" and register
these along with the device. None of them define any
other platform data so just pass NULL as platform data.
This platform selects GPIOLIB so all should be smooth.
The pins appear on a gpiochip for bank "G" as pins 1 (SDA)
and 0 (SCL).
- IXP4 (arch/arm/mach-ixp4): descriptor tables have to
be registered for each board separately. They all use
"IXP4XX_GPIO_CHIP" so it is pretty straight forward.
Most board define no other platform data than SCL/SDA
so they can drop the #include of <linux/i2c-gpio.h> and
assign NULL to platform data.
The "goramo_mlr" (Goramo Multilink Router) board is a bit
worrisome: it implements its own I2C bit-banging in the
board file, and optionally registers an I2C serial port,
but claims the same GPIO lines for itself in the board file.
This is not going to work: there will be competition for the
GPIO lines, so delete the optional extra I2C bus instead, no
I2C devices are registered on it anyway, there are just hints
that it may contain an EEPROM that may be accessed from
userspace. This needs to be fixed up properly by the serial
clock using I2C emulation so drop a note in the code.
- KS8695 board acs5k (arch/arm/mach-ks8695/board-acs5.c)
has some platform data in addition to the pins so it needs to
be kept around sans GPIO lines. Its GPIO chip is named
"KS8695" and the arch selects GPIOLIB.
- PXA boards (arch/arm/mach-pxa/*) use some of the platform
data so it needs to be preserved here. The viper board even
registers two GPIO I2Cs. The gpiochip is named "gpio-pxa" and
the arch selects GPIOLIB.
- SA1100 Simpad (arch/arm/mach-sa1100/simpad.c) defines a GPIO
I2C bus, and the arch selects GPIOLIB.
- Blackfin boards (arch/blackfin/bf533 etc) for these I assume
their I2C GPIOs refer to the local gpiochip defined in
arch/blackfin/kernel/bfin_gpio.c names "BFIN-GPIO".
The arch selects GPIOLIB. The boards get spiked with
IF_ENABLED(I2C_GPIO) but that is a side effect of it
being like that already (I would just have Kconfig select
I2C_GPIO and get rid of them all.) I also delete any
platform data set to 0 as it will get that value anyway
from static declartions of platform data.
- The MIPS selects GPIOLIB and the Alchemy machine is using
two local GPIO chips, one of them has a GPIO I2C. We need
to adjust the local offset from the global number space here.
The ATH79 has a proper GPIO driver in drivers/gpio/gpio-ath79.c
and AFAICT the chip is named "ath79-gpio" and the PB44
PCF857x expander spawns from this on GPIO 1 and 0. The latter
board only use the platform data to specify pins so it can be
cut altogether after this.
- The MFD Silicon Motion SM501 is a special case. It dynamically
spawns an I2C bus off the MFD using sm501_create_subdev().
We use an approach to dynamically create a machine descriptor
table and attach this to the "SM501-LOW" or "SM501-HIGH"
gpiochip. We use chip-local offsets to grab the right lines.
We can get rid of two local static inline helpers as part
of this refactoring.
Cc: Steven Miao <realmz6@gmail.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Magnus Damm <magnus.damm@gmail.com>
Cc: Ben Dooks <ben.dooks@codethink.co.uk>
Cc: Heiko Schocher <hs@denx.de>
Acked-by: Wu, Aaron <Aaron.Wu@analog.com>
Acked-by: Olof Johansson <olof@lixom.net>
Acked-by: Lee Jones <lee.jones@linaro.org>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2017-09-10 07:30:46 +08:00
|
|
|
desc_to_gpio(priv->sda), desc_to_gpio(priv->scl),
|
i2c: Bitbanging I2C bus driver using the GPIO API
This is a very simple bitbanging I2C bus driver utilizing the new
arch-neutral GPIO API. Useful for chips that don't have a built-in
I2C controller, additional I2C busses, or testing purposes.
To use, include something similar to the following in the
board-specific setup code:
#include <linux/i2c-gpio.h>
static struct i2c_gpio_platform_data i2c_gpio_data = {
.sda_pin = GPIO_PIN_FOO,
.scl_pin = GPIO_PIN_BAR,
};
static struct platform_device i2c_gpio_device = {
.name = "i2c-gpio",
.id = 0,
.dev = {
.platform_data = &i2c_gpio_data,
},
};
Register this platform_device, set up the I2C pins as GPIO if
required and you're ready to go. This will use default values for
udelay and timeout, and will work with GPIO hardware that does not
support open drain mode, but allows sensing of the SDA and SCL lines
even when they are being driven.
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2007-05-02 05:26:34 +08:00
|
|
|
pdata->scl_is_output_only
|
|
|
|
? ", no clock stretching" : "");
|
|
|
|
|
2017-11-28 23:53:32 +08:00
|
|
|
i2c_gpio_fault_injector_init(pdev);
|
|
|
|
|
i2c: Bitbanging I2C bus driver using the GPIO API
This is a very simple bitbanging I2C bus driver utilizing the new
arch-neutral GPIO API. Useful for chips that don't have a built-in
I2C controller, additional I2C busses, or testing purposes.
To use, include something similar to the following in the
board-specific setup code:
#include <linux/i2c-gpio.h>
static struct i2c_gpio_platform_data i2c_gpio_data = {
.sda_pin = GPIO_PIN_FOO,
.scl_pin = GPIO_PIN_BAR,
};
static struct platform_device i2c_gpio_device = {
.name = "i2c-gpio",
.id = 0,
.dev = {
.platform_data = &i2c_gpio_data,
},
};
Register this platform_device, set up the I2C pins as GPIO if
required and you're ready to go. This will use default values for
udelay and timeout, and will work with GPIO hardware that does not
support open drain mode, but allows sensing of the SDA and SCL lines
even when they are being driven.
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2007-05-02 05:26:34 +08:00
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2012-11-28 04:59:38 +08:00
|
|
|
static int i2c_gpio_remove(struct platform_device *pdev)
|
i2c: Bitbanging I2C bus driver using the GPIO API
This is a very simple bitbanging I2C bus driver utilizing the new
arch-neutral GPIO API. Useful for chips that don't have a built-in
I2C controller, additional I2C busses, or testing purposes.
To use, include something similar to the following in the
board-specific setup code:
#include <linux/i2c-gpio.h>
static struct i2c_gpio_platform_data i2c_gpio_data = {
.sda_pin = GPIO_PIN_FOO,
.scl_pin = GPIO_PIN_BAR,
};
static struct platform_device i2c_gpio_device = {
.name = "i2c-gpio",
.id = 0,
.dev = {
.platform_data = &i2c_gpio_data,
},
};
Register this platform_device, set up the I2C pins as GPIO if
required and you're ready to go. This will use default values for
udelay and timeout, and will work with GPIO hardware that does not
support open drain mode, but allows sensing of the SDA and SCL lines
even when they are being driven.
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2007-05-02 05:26:34 +08:00
|
|
|
{
|
2012-02-05 18:22:34 +08:00
|
|
|
struct i2c_gpio_private_data *priv;
|
i2c: Bitbanging I2C bus driver using the GPIO API
This is a very simple bitbanging I2C bus driver utilizing the new
arch-neutral GPIO API. Useful for chips that don't have a built-in
I2C controller, additional I2C busses, or testing purposes.
To use, include something similar to the following in the
board-specific setup code:
#include <linux/i2c-gpio.h>
static struct i2c_gpio_platform_data i2c_gpio_data = {
.sda_pin = GPIO_PIN_FOO,
.scl_pin = GPIO_PIN_BAR,
};
static struct platform_device i2c_gpio_device = {
.name = "i2c-gpio",
.id = 0,
.dev = {
.platform_data = &i2c_gpio_data,
},
};
Register this platform_device, set up the I2C pins as GPIO if
required and you're ready to go. This will use default values for
udelay and timeout, and will work with GPIO hardware that does not
support open drain mode, but allows sensing of the SDA and SCL lines
even when they are being driven.
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2007-05-02 05:26:34 +08:00
|
|
|
struct i2c_adapter *adap;
|
|
|
|
|
2017-11-28 23:53:32 +08:00
|
|
|
i2c_gpio_fault_injector_exit(pdev);
|
|
|
|
|
2012-02-05 18:22:34 +08:00
|
|
|
priv = platform_get_drvdata(pdev);
|
|
|
|
adap = &priv->adap;
|
i2c: Bitbanging I2C bus driver using the GPIO API
This is a very simple bitbanging I2C bus driver utilizing the new
arch-neutral GPIO API. Useful for chips that don't have a built-in
I2C controller, additional I2C busses, or testing purposes.
To use, include something similar to the following in the
board-specific setup code:
#include <linux/i2c-gpio.h>
static struct i2c_gpio_platform_data i2c_gpio_data = {
.sda_pin = GPIO_PIN_FOO,
.scl_pin = GPIO_PIN_BAR,
};
static struct platform_device i2c_gpio_device = {
.name = "i2c-gpio",
.id = 0,
.dev = {
.platform_data = &i2c_gpio_data,
},
};
Register this platform_device, set up the I2C pins as GPIO if
required and you're ready to go. This will use default values for
udelay and timeout, and will work with GPIO hardware that does not
support open drain mode, but allows sensing of the SDA and SCL lines
even when they are being driven.
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2007-05-02 05:26:34 +08:00
|
|
|
|
|
|
|
i2c_del_adapter(adap);
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2012-02-05 18:22:34 +08:00
|
|
|
#if defined(CONFIG_OF)
|
|
|
|
static const struct of_device_id i2c_gpio_dt_ids[] = {
|
|
|
|
{ .compatible = "i2c-gpio", },
|
|
|
|
{ /* sentinel */ }
|
|
|
|
};
|
|
|
|
|
|
|
|
MODULE_DEVICE_TABLE(of, i2c_gpio_dt_ids);
|
|
|
|
#endif
|
|
|
|
|
i2c: Bitbanging I2C bus driver using the GPIO API
This is a very simple bitbanging I2C bus driver utilizing the new
arch-neutral GPIO API. Useful for chips that don't have a built-in
I2C controller, additional I2C busses, or testing purposes.
To use, include something similar to the following in the
board-specific setup code:
#include <linux/i2c-gpio.h>
static struct i2c_gpio_platform_data i2c_gpio_data = {
.sda_pin = GPIO_PIN_FOO,
.scl_pin = GPIO_PIN_BAR,
};
static struct platform_device i2c_gpio_device = {
.name = "i2c-gpio",
.id = 0,
.dev = {
.platform_data = &i2c_gpio_data,
},
};
Register this platform_device, set up the I2C pins as GPIO if
required and you're ready to go. This will use default values for
udelay and timeout, and will work with GPIO hardware that does not
support open drain mode, but allows sensing of the SDA and SCL lines
even when they are being driven.
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2007-05-02 05:26:34 +08:00
|
|
|
static struct platform_driver i2c_gpio_driver = {
|
|
|
|
.driver = {
|
|
|
|
.name = "i2c-gpio",
|
2012-02-05 18:22:34 +08:00
|
|
|
.of_match_table = of_match_ptr(i2c_gpio_dt_ids),
|
i2c: Bitbanging I2C bus driver using the GPIO API
This is a very simple bitbanging I2C bus driver utilizing the new
arch-neutral GPIO API. Useful for chips that don't have a built-in
I2C controller, additional I2C busses, or testing purposes.
To use, include something similar to the following in the
board-specific setup code:
#include <linux/i2c-gpio.h>
static struct i2c_gpio_platform_data i2c_gpio_data = {
.sda_pin = GPIO_PIN_FOO,
.scl_pin = GPIO_PIN_BAR,
};
static struct platform_device i2c_gpio_device = {
.name = "i2c-gpio",
.id = 0,
.dev = {
.platform_data = &i2c_gpio_data,
},
};
Register this platform_device, set up the I2C pins as GPIO if
required and you're ready to go. This will use default values for
udelay and timeout, and will work with GPIO hardware that does not
support open drain mode, but allows sensing of the SDA and SCL lines
even when they are being driven.
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2007-05-02 05:26:34 +08:00
|
|
|
},
|
2008-07-28 19:04:09 +08:00
|
|
|
.probe = i2c_gpio_probe,
|
2012-11-28 04:59:38 +08:00
|
|
|
.remove = i2c_gpio_remove,
|
i2c: Bitbanging I2C bus driver using the GPIO API
This is a very simple bitbanging I2C bus driver utilizing the new
arch-neutral GPIO API. Useful for chips that don't have a built-in
I2C controller, additional I2C busses, or testing purposes.
To use, include something similar to the following in the
board-specific setup code:
#include <linux/i2c-gpio.h>
static struct i2c_gpio_platform_data i2c_gpio_data = {
.sda_pin = GPIO_PIN_FOO,
.scl_pin = GPIO_PIN_BAR,
};
static struct platform_device i2c_gpio_device = {
.name = "i2c-gpio",
.id = 0,
.dev = {
.platform_data = &i2c_gpio_data,
},
};
Register this platform_device, set up the I2C pins as GPIO if
required and you're ready to go. This will use default values for
udelay and timeout, and will work with GPIO hardware that does not
support open drain mode, but allows sensing of the SDA and SCL lines
even when they are being driven.
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2007-05-02 05:26:34 +08:00
|
|
|
};
|
|
|
|
|
|
|
|
static int __init i2c_gpio_init(void)
|
|
|
|
{
|
|
|
|
int ret;
|
|
|
|
|
2008-07-28 19:04:09 +08:00
|
|
|
ret = platform_driver_register(&i2c_gpio_driver);
|
i2c: Bitbanging I2C bus driver using the GPIO API
This is a very simple bitbanging I2C bus driver utilizing the new
arch-neutral GPIO API. Useful for chips that don't have a built-in
I2C controller, additional I2C busses, or testing purposes.
To use, include something similar to the following in the
board-specific setup code:
#include <linux/i2c-gpio.h>
static struct i2c_gpio_platform_data i2c_gpio_data = {
.sda_pin = GPIO_PIN_FOO,
.scl_pin = GPIO_PIN_BAR,
};
static struct platform_device i2c_gpio_device = {
.name = "i2c-gpio",
.id = 0,
.dev = {
.platform_data = &i2c_gpio_data,
},
};
Register this platform_device, set up the I2C pins as GPIO if
required and you're ready to go. This will use default values for
udelay and timeout, and will work with GPIO hardware that does not
support open drain mode, but allows sensing of the SDA and SCL lines
even when they are being driven.
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2007-05-02 05:26:34 +08:00
|
|
|
if (ret)
|
|
|
|
printk(KERN_ERR "i2c-gpio: probe failed: %d\n", ret);
|
|
|
|
|
|
|
|
return ret;
|
|
|
|
}
|
2010-05-22 00:40:58 +08:00
|
|
|
subsys_initcall(i2c_gpio_init);
|
i2c: Bitbanging I2C bus driver using the GPIO API
This is a very simple bitbanging I2C bus driver utilizing the new
arch-neutral GPIO API. Useful for chips that don't have a built-in
I2C controller, additional I2C busses, or testing purposes.
To use, include something similar to the following in the
board-specific setup code:
#include <linux/i2c-gpio.h>
static struct i2c_gpio_platform_data i2c_gpio_data = {
.sda_pin = GPIO_PIN_FOO,
.scl_pin = GPIO_PIN_BAR,
};
static struct platform_device i2c_gpio_device = {
.name = "i2c-gpio",
.id = 0,
.dev = {
.platform_data = &i2c_gpio_data,
},
};
Register this platform_device, set up the I2C pins as GPIO if
required and you're ready to go. This will use default values for
udelay and timeout, and will work with GPIO hardware that does not
support open drain mode, but allows sensing of the SDA and SCL lines
even when they are being driven.
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2007-05-02 05:26:34 +08:00
|
|
|
|
|
|
|
static void __exit i2c_gpio_exit(void)
|
|
|
|
{
|
|
|
|
platform_driver_unregister(&i2c_gpio_driver);
|
|
|
|
}
|
|
|
|
module_exit(i2c_gpio_exit);
|
|
|
|
|
2011-05-18 22:49:24 +08:00
|
|
|
MODULE_AUTHOR("Haavard Skinnemoen (Atmel)");
|
i2c: Bitbanging I2C bus driver using the GPIO API
This is a very simple bitbanging I2C bus driver utilizing the new
arch-neutral GPIO API. Useful for chips that don't have a built-in
I2C controller, additional I2C busses, or testing purposes.
To use, include something similar to the following in the
board-specific setup code:
#include <linux/i2c-gpio.h>
static struct i2c_gpio_platform_data i2c_gpio_data = {
.sda_pin = GPIO_PIN_FOO,
.scl_pin = GPIO_PIN_BAR,
};
static struct platform_device i2c_gpio_device = {
.name = "i2c-gpio",
.id = 0,
.dev = {
.platform_data = &i2c_gpio_data,
},
};
Register this platform_device, set up the I2C pins as GPIO if
required and you're ready to go. This will use default values for
udelay and timeout, and will work with GPIO hardware that does not
support open drain mode, but allows sensing of the SDA and SCL lines
even when they are being driven.
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2007-05-02 05:26:34 +08:00
|
|
|
MODULE_DESCRIPTION("Platform-independent bitbanging I2C driver");
|
|
|
|
MODULE_LICENSE("GPL");
|
2008-04-23 04:16:49 +08:00
|
|
|
MODULE_ALIAS("platform:i2c-gpio");
|