i2c: mux: ltc4306: LTC4306 and LTC4305 I2C multiplexer/switch
This patch adds support for the Analog Devices / Linear Technology LTC4306 and LTC4305 4/2 Channel I2C Bus Multiplexer/Switches. The LTC4306 optionally provides two general purpose input/output pins (GPIOs) that can be configured as logic inputs, opendrain outputs or push-pull outputs via the generic GPIOLIB framework. Signed-off-by: Michael Hennerich <michael.hennerich@analog.com> Reviewed-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Peter Rosin <peda@axentia.se>
This commit is contained in:
Michael Hennerich
Peter Rosin
parent
84ffac8971
commit
dbed8a803b
|
|
@ -7698,6 +7698,14 @@ S: Maintained
|
|||
F: Documentation/hwmon/ltc4261
|
||||
F: drivers/hwmon/ltc4261.c
|
||||
|
||||
LTC4306 I2C MULTIPLEXER DRIVER
|
||||
M: Michael Hennerich <michael.hennerich@analog.com>
|
||||
W: http://ez.analog.com/community/linux-device-drivers
|
||||
L: linux-i2c@vger.kernel.org
|
||||
S: Supported
|
||||
F: drivers/i2c/muxes/i2c-mux-ltc4306.c
|
||||
F: Documentation/devicetree/bindings/i2c/i2c-mux-ltc4306.txt
|
||||
|
||||
LTP (Linux Test Project)
|
||||
M: Mike Frysinger <vapier@gentoo.org>
|
||||
M: Cyril Hrubis <chrubis@suse.cz>
|
||||
|
|
|
|||
|
|
@ -30,6 +30,17 @@ config I2C_MUX_GPIO
|
|||
This driver can also be built as a module. If so, the module
|
||||
will be called i2c-mux-gpio.
|
||||
|
||||
config I2C_MUX_LTC4306
|
||||
tristate "LTC LTC4306/5 I2C multiplexer"
|
||||
select GPIOLIB
|
||||
select REGMAP_I2C
|
||||
help
|
||||
If you say yes here you get support for the Analog Devices
|
||||
LTC4306 or LTC4305 I2C mux/switch devices.
|
||||
|
||||
This driver can also be built as a module. If so, the module
|
||||
will be called i2c-mux-ltc4306.
|
||||
|
||||
config I2C_MUX_PCA9541
|
||||
tristate "NXP PCA9541 I2C Master Selector"
|
||||
help
|
||||
|
|
|
|||
|
|
@ -6,6 +6,7 @@ obj-$(CONFIG_I2C_ARB_GPIO_CHALLENGE) += i2c-arb-gpio-challenge.o
|
|||
obj-$(CONFIG_I2C_DEMUX_PINCTRL) += i2c-demux-pinctrl.o
|
||||
|
||||
obj-$(CONFIG_I2C_MUX_GPIO) += i2c-mux-gpio.o
|
||||
obj-$(CONFIG_I2C_MUX_LTC4306) += i2c-mux-ltc4306.o
|
||||
obj-$(CONFIG_I2C_MUX_MLXCPLD) += i2c-mux-mlxcpld.o
|
||||
obj-$(CONFIG_I2C_MUX_PCA9541) += i2c-mux-pca9541.o
|
||||
obj-$(CONFIG_I2C_MUX_PCA954x) += i2c-mux-pca954x.o
|
||||
|
|
|
|||
|
|
@ -0,0 +1,322 @@
|
|||
/*
|
||||
* Linear Technology LTC4306 and LTC4305 I2C multiplexer/switch
|
||||
*
|
||||
* Copyright (C) 2017 Analog Devices Inc.
|
||||
*
|
||||
* Licensed under the GPL-2.
|
||||
*
|
||||
* Based on: i2c-mux-pca954x.c
|
||||
*
|
||||
* Datasheet: http://cds.linear.com/docs/en/datasheet/4306.pdf
|
||||
*/
|
||||
|
||||
#include <linux/gpio/consumer.h>
|
||||
#include <linux/gpio/driver.h>
|
||||
#include <linux/i2c-mux.h>
|
||||
#include <linux/i2c.h>
|
||||
#include <linux/module.h>
|
||||
#include <linux/of.h>
|
||||
#include <linux/of_device.h>
|
||||
#include <linux/property.h>
|
||||
#include <linux/regmap.h>
|
||||
#include <linux/slab.h>
|
||||
|
||||
#define LTC4305_MAX_NCHANS 2
|
||||
#define LTC4306_MAX_NCHANS 4
|
||||
|
||||
#define LTC_REG_STATUS 0x0
|
||||
#define LTC_REG_CONFIG 0x1
|
||||
#define LTC_REG_MODE 0x2
|
||||
#define LTC_REG_SWITCH 0x3
|
||||
|
||||
#define LTC_DOWNSTREAM_ACCL_EN BIT(6)
|
||||
#define LTC_UPSTREAM_ACCL_EN BIT(7)
|
||||
|
||||
#define LTC_GPIO_ALL_INPUT 0xC0
|
||||
#define LTC_SWITCH_MASK 0xF0
|
||||
|
||||
enum ltc_type {
|
||||
ltc_4305,
|
||||
ltc_4306,
|
||||
};
|
||||
|
||||
struct chip_desc {
|
||||
u8 nchans;
|
||||
u8 num_gpios;
|
||||
};
|
||||
|
||||
struct ltc4306 {
|
||||
struct regmap *regmap;
|
||||
struct gpio_chip gpiochip;
|
||||
const struct chip_desc *chip;
|
||||
};
|
||||
|
||||
static const struct chip_desc chips[] = {
|
||||
[ltc_4305] = {
|
||||
.nchans = LTC4305_MAX_NCHANS,
|
||||
},
|
||||
[ltc_4306] = {
|
||||
.nchans = LTC4306_MAX_NCHANS,
|
||||
.num_gpios = 2,
|
||||
},
|
||||
};
|
||||
|
||||
static bool ltc4306_is_volatile_reg(struct device *dev, unsigned int reg)
|
||||
{
|
||||
return (reg == LTC_REG_CONFIG) ? true : false;
|
||||
}
|
||||
|
||||
static const struct regmap_config ltc4306_regmap_config = {
|
||||
.reg_bits = 8,
|
||||
.val_bits = 8,
|
||||
.max_register = LTC_REG_SWITCH,
|
||||
.volatile_reg = ltc4306_is_volatile_reg,
|
||||
.cache_type = REGCACHE_FLAT,
|
||||
};
|
||||
|
||||
static int ltc4306_gpio_get(struct gpio_chip *chip, unsigned int offset)
|
||||
{
|
||||
struct ltc4306 *data = gpiochip_get_data(chip);
|
||||
unsigned int val;
|
||||
int ret;
|
||||
|
||||
ret = regmap_read(data->regmap, LTC_REG_CONFIG, &val);
|
||||
if (ret < 0)
|
||||
return ret;
|
||||
|
||||
return !!(val & BIT(1 - offset));
|
||||
}
|
||||
|
||||
static void ltc4306_gpio_set(struct gpio_chip *chip, unsigned int offset,
|
||||
int value)
|
||||
{
|
||||
struct ltc4306 *data = gpiochip_get_data(chip);
|
||||
|
||||
regmap_update_bits(data->regmap, LTC_REG_CONFIG, BIT(5 - offset),
|
||||
value ? BIT(5 - offset) : 0);
|
||||
}
|
||||
|
||||
static int ltc4306_gpio_get_direction(struct gpio_chip *chip,
|
||||
unsigned int offset)
|
||||
{
|
||||
struct ltc4306 *data = gpiochip_get_data(chip);
|
||||
unsigned int val;
|
||||
int ret;
|
||||
|
||||
ret = regmap_read(data->regmap, LTC_REG_MODE, &val);
|
||||
if (ret < 0)
|
||||
return ret;
|
||||
|
||||
return !!(val & BIT(7 - offset));
|
||||
}
|
||||
|
||||
static int ltc4306_gpio_direction_input(struct gpio_chip *chip,
|
||||
unsigned int offset)
|
||||
{
|
||||
struct ltc4306 *data = gpiochip_get_data(chip);
|
||||
|
||||
return regmap_update_bits(data->regmap, LTC_REG_MODE,
|
||||
BIT(7 - offset), BIT(7 - offset));
|
||||
}
|
||||
|
||||
static int ltc4306_gpio_direction_output(struct gpio_chip *chip,
|
||||
unsigned int offset, int value)
|
||||
{
|
||||
struct ltc4306 *data = gpiochip_get_data(chip);
|
||||
|
||||
ltc4306_gpio_set(chip, offset, value);
|
||||
return regmap_update_bits(data->regmap, LTC_REG_MODE,
|
||||
BIT(7 - offset), 0);
|
||||
}
|
||||
|
||||
static int ltc4306_gpio_set_config(struct gpio_chip *chip,
|
||||
unsigned int offset, unsigned long config)
|
||||
{
|
||||
struct ltc4306 *data = gpiochip_get_data(chip);
|
||||
unsigned int val;
|
||||
|
||||
switch (pinconf_to_config_param(config)) {
|
||||
case PIN_CONFIG_DRIVE_OPEN_DRAIN:
|
||||
val = 0;
|
||||
break;
|
||||
case PIN_CONFIG_DRIVE_PUSH_PULL:
|
||||
val = BIT(4 - offset);
|
||||
break;
|
||||
default:
|
||||
return -ENOTSUPP;
|
||||
}
|
||||
|
||||
return regmap_update_bits(data->regmap, LTC_REG_MODE,
|
||||
BIT(4 - offset), val);
|
||||
}
|
||||
|
||||
static int ltc4306_gpio_init(struct ltc4306 *data)
|
||||
{
|
||||
struct device *dev = regmap_get_device(data->regmap);
|
||||
|
||||
if (!data->chip->num_gpios)
|
||||
return 0;
|
||||
|
||||
data->gpiochip.label = dev_name(dev);
|
||||
data->gpiochip.base = -1;
|
||||
data->gpiochip.ngpio = data->chip->num_gpios;
|
||||
data->gpiochip.parent = dev;
|
||||
data->gpiochip.can_sleep = true;
|
||||
data->gpiochip.get_direction = ltc4306_gpio_get_direction;
|
||||
data->gpiochip.direction_input = ltc4306_gpio_direction_input;
|
||||
data->gpiochip.direction_output = ltc4306_gpio_direction_output;
|
||||
data->gpiochip.get = ltc4306_gpio_get;
|
||||
data->gpiochip.set = ltc4306_gpio_set;
|
||||
data->gpiochip.set_config = ltc4306_gpio_set_config;
|
||||
data->gpiochip.owner = THIS_MODULE;
|
||||
|
||||
/* gpiolib assumes all GPIOs default input */
|
||||
regmap_write(data->regmap, LTC_REG_MODE, LTC_GPIO_ALL_INPUT);
|
||||
|
||||
return devm_gpiochip_add_data(dev, &data->gpiochip, data);
|
||||
}
|
||||
|
||||
static int ltc4306_select_mux(struct i2c_mux_core *muxc, u32 chan)
|
||||
{
|
||||
struct ltc4306 *data = i2c_mux_priv(muxc);
|
||||
|
||||
return regmap_update_bits(data->regmap, LTC_REG_SWITCH,
|
||||
LTC_SWITCH_MASK, BIT(7 - chan));
|
||||
}
|
||||
|
||||
static int ltc4306_deselect_mux(struct i2c_mux_core *muxc, u32 chan)
|
||||
{
|
||||
struct ltc4306 *data = i2c_mux_priv(muxc);
|
||||
|
||||
return regmap_update_bits(data->regmap, LTC_REG_SWITCH,
|
||||
LTC_SWITCH_MASK, 0);
|
||||
}
|
||||
|
||||
static const struct i2c_device_id ltc4306_id[] = {
|
||||
{ "ltc4305", ltc_4305 },
|
||||
{ "ltc4306", ltc_4306 },
|
||||
{ }
|
||||
};
|
||||
MODULE_DEVICE_TABLE(i2c, ltc4306_id);
|
||||
|
||||
static const struct of_device_id ltc4306_of_match[] = {
|
||||
{ .compatible = "lltc,ltc4305", .data = &chips[ltc_4305] },
|
||||
{ .compatible = "lltc,ltc4306", .data = &chips[ltc_4306] },
|
||||
{ }
|
||||
};
|
||||
MODULE_DEVICE_TABLE(of, ltc4306_of_match);
|
||||
|
||||
static int ltc4306_probe(struct i2c_client *client,
|
||||
const struct i2c_device_id *id)
|
||||
{
|
||||
struct i2c_adapter *adap = to_i2c_adapter(client->dev.parent);
|
||||
const struct chip_desc *chip;
|
||||
struct i2c_mux_core *muxc;
|
||||
struct ltc4306 *data;
|
||||
struct gpio_desc *gpio;
|
||||
bool idle_disc;
|
||||
unsigned int val = 0;
|
||||
int num, ret;
|
||||
|
||||
chip = of_device_get_match_data(&client->dev);
|
||||
|
||||
if (!chip)
|
||||
chip = &chips[id->driver_data];
|
||||
|
||||
idle_disc = device_property_read_bool(&client->dev,
|
||||
"i2c-mux-idle-disconnect");
|
||||
|
||||
muxc = i2c_mux_alloc(adap, &client->dev,
|
||||
chip->nchans, sizeof(*data),
|
||||
I2C_MUX_LOCKED, ltc4306_select_mux,
|
||||
idle_disc ? ltc4306_deselect_mux : NULL);
|
||||
if (!muxc)
|
||||
return -ENOMEM;
|
||||
data = i2c_mux_priv(muxc);
|
||||
data->chip = chip;
|
||||
|
||||
i2c_set_clientdata(client, muxc);
|
||||
|
||||
data->regmap = devm_regmap_init_i2c(client, <c4306_regmap_config);
|
||||
if (IS_ERR(data->regmap)) {
|
||||
ret = PTR_ERR(data->regmap);
|
||||
dev_err(&client->dev, "Failed to allocate register map: %d\n",
|
||||
ret);
|
||||
return ret;
|
||||
}
|
||||
|
||||
/* Reset and enable the mux if an enable GPIO is specified. */
|
||||
gpio = devm_gpiod_get_optional(&client->dev, "enable", GPIOD_OUT_LOW);
|
||||
if (IS_ERR(gpio))
|
||||
return PTR_ERR(gpio);
|
||||
|
||||
if (gpio) {
|
||||
udelay(1);
|
||||
gpiod_set_value(gpio, 1);
|
||||
}
|
||||
|
||||
/*
|
||||
* Write the mux register at addr to verify
|
||||
* that the mux is in fact present. This also
|
||||
* initializes the mux to disconnected state.
|
||||
*/
|
||||
if (regmap_write(data->regmap, LTC_REG_SWITCH, 0) < 0) {
|
||||
dev_warn(&client->dev, "probe failed\n");
|
||||
return -ENODEV;
|
||||
}
|
||||
|
||||
if (device_property_read_bool(&client->dev,
|
||||
"ltc,downstream-accelerators-enable"))
|
||||
val |= LTC_DOWNSTREAM_ACCL_EN;
|
||||
|
||||
if (device_property_read_bool(&client->dev,
|
||||
"ltc,upstream-accelerators-enable"))
|
||||
val |= LTC_UPSTREAM_ACCL_EN;
|
||||
|
||||
if (regmap_write(data->regmap, LTC_REG_CONFIG, val) < 0)
|
||||
return -ENODEV;
|
||||
|
||||
ret = ltc4306_gpio_init(data);
|
||||
if (ret < 0)
|
||||
return ret;
|
||||
|
||||
/* Now create an adapter for each channel */
|
||||
for (num = 0; num < chip->nchans; num++) {
|
||||
ret = i2c_mux_add_adapter(muxc, 0, num, 0);
|
||||
if (ret) {
|
||||
i2c_mux_del_adapters(muxc);
|
||||
return ret;
|
||||
}
|
||||
}
|
||||
|
||||
dev_info(&client->dev,
|
||||
"registered %d multiplexed busses for I2C switch %s\n",
|
||||
num, client->name);
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int ltc4306_remove(struct i2c_client *client)
|
||||
{
|
||||
struct i2c_mux_core *muxc = i2c_get_clientdata(client);
|
||||
|
||||
i2c_mux_del_adapters(muxc);
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static struct i2c_driver ltc4306_driver = {
|
||||
.driver = {
|
||||
.name = "ltc4306",
|
||||
.of_match_table = of_match_ptr(ltc4306_of_match),
|
||||
},
|
||||
.probe = ltc4306_probe,
|
||||
.remove = ltc4306_remove,
|
||||
.id_table = ltc4306_id,
|
||||
};
|
||||
|
||||
module_i2c_driver(ltc4306_driver);
|
||||
|
||||
MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
|
||||
MODULE_DESCRIPTION("Linear Technology LTC4306, LTC4305 I2C mux/switch driver");
|
||||
MODULE_LICENSE("GPL v2");
|
||||
Loading…
Reference in New Issue