iio:adc: Driver for Linear Technology LTC2497 ADC
This patch adds support for the Analog Devices / Linear Technology LTC2497 ADCs. The LTC2497 is a 16-channel (eight differential), 16-bit, high precision, delta-sigma ADC with an automatic, differential, input current cancellation front end and a 2-wire, I2C interface. Signed-off-by: Michael Hennerich <michael.hennerich@analog.com> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
This commit is contained in:
Michael Hennerich
Jonathan Cameron
parent
13e283d6fc
commit
bc82222fcc
|
|
@ -0,0 +1,13 @@
|
|||
* Linear Technology / Analog Devices LTC2497 ADC
|
||||
|
||||
Required properties:
|
||||
- compatible: Must be "lltc,ltc2497"
|
||||
- reg: Must contain the ADC I2C address
|
||||
- vref-supply: The regulator supply for ADC reference voltage
|
||||
|
||||
Example:
|
||||
ltc2497: adc@76 {
|
||||
compatible = "lltc,ltc2497";
|
||||
reg = <0x76>;
|
||||
vref-supply = <<c2497_reg>;
|
||||
};
|
||||
|
|
@ -813,6 +813,7 @@ W: http://wiki.analog.com/
|
|||
W: http://ez.analog.com/community/linux-device-drivers
|
||||
S: Supported
|
||||
F: drivers/iio/*/ad*
|
||||
F: drivers/iio/adc/ltc2497*
|
||||
X: drivers/iio/*/adjd*
|
||||
F: drivers/staging/iio/*/ad*
|
||||
F: drivers/staging/iio/trigger/iio-trig-bfin-timer.c
|
||||
|
|
|
|||
|
|
@ -348,6 +348,16 @@ config LTC2485
|
|||
To compile this driver as a module, choose M here: the module will be
|
||||
called ltc2485.
|
||||
|
||||
config LTC2497
|
||||
tristate "Linear Technology LTC2497 ADC driver"
|
||||
depends on I2C
|
||||
help
|
||||
Say yes here to build support for Linear Technology LTC2497
|
||||
16-Bit 8-/16-Channel Delta Sigma ADC.
|
||||
|
||||
To compile this driver as a module, choose M here: the module will be
|
||||
called ltc2497.
|
||||
|
||||
config MAX1027
|
||||
tristate "Maxim max1027 ADC driver"
|
||||
depends on SPI
|
||||
|
|
|
|||
|
|
@ -34,6 +34,7 @@ obj-$(CONFIG_LP8788_ADC) += lp8788_adc.o
|
|||
obj-$(CONFIG_LPC18XX_ADC) += lpc18xx_adc.o
|
||||
obj-$(CONFIG_LPC32XX_ADC) += lpc32xx_adc.o
|
||||
obj-$(CONFIG_LTC2485) += ltc2485.o
|
||||
obj-$(CONFIG_LTC2497) += ltc2497.o
|
||||
obj-$(CONFIG_MAX1027) += max1027.o
|
||||
obj-$(CONFIG_MAX11100) += max11100.o
|
||||
obj-$(CONFIG_MAX1363) += max1363.o
|
||||
|
|
|
|||
|
|
@ -0,0 +1,279 @@
|
|||
/*
|
||||
* ltc2497.c - Driver for Analog Devices/Linear Technology LTC2497 ADC
|
||||
*
|
||||
* Copyright (C) 2017 Analog Devices Inc.
|
||||
*
|
||||
* Licensed under the GPL-2.
|
||||
*
|
||||
* Datasheet: http://cds.linear.com/docs/en/datasheet/2497fd.pdf
|
||||
*/
|
||||
|
||||
#include <linux/delay.h>
|
||||
#include <linux/i2c.h>
|
||||
#include <linux/iio/iio.h>
|
||||
#include <linux/iio/sysfs.h>
|
||||
#include <linux/module.h>
|
||||
#include <linux/of.h>
|
||||
#include <linux/regulator/consumer.h>
|
||||
|
||||
#define LTC2497_ENABLE 0xA0
|
||||
#define LTC2497_SGL BIT(4)
|
||||
#define LTC2497_DIFF 0
|
||||
#define LTC2497_SIGN BIT(3)
|
||||
#define LTC2497_CONFIG_DEFAULT LTC2497_ENABLE
|
||||
#define LTC2497_CONVERSION_TIME_MS 150ULL
|
||||
|
||||
struct ltc2497_st {
|
||||
struct i2c_client *client;
|
||||
struct regulator *ref;
|
||||
ktime_t time_prev;
|
||||
u8 addr_prev;
|
||||
/*
|
||||
* DMA (thus cache coherency maintenance) requires the
|
||||
* transfer buffers to live in their own cache lines.
|
||||
*/
|
||||
__be32 buf ____cacheline_aligned;
|
||||
};
|
||||
|
||||
static int ltc2497_wait_conv(struct ltc2497_st *st)
|
||||
{
|
||||
s64 time_elapsed;
|
||||
|
||||
time_elapsed = ktime_ms_delta(ktime_get(), st->time_prev);
|
||||
|
||||
if (time_elapsed < LTC2497_CONVERSION_TIME_MS) {
|
||||
/* delay if conversion time not passed
|
||||
* since last read or write
|
||||
*/
|
||||
if (msleep_interruptible(
|
||||
LTC2497_CONVERSION_TIME_MS - time_elapsed))
|
||||
return -ERESTARTSYS;
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
if (time_elapsed - LTC2497_CONVERSION_TIME_MS <= 0) {
|
||||
/* We're in automatic mode -
|
||||
* so the last reading is stil not outdated
|
||||
*/
|
||||
return 0;
|
||||
}
|
||||
|
||||
return 1;
|
||||
}
|
||||
|
||||
static int ltc2497_read(struct ltc2497_st *st, u8 address, int *val)
|
||||
{
|
||||
struct i2c_client *client = st->client;
|
||||
int ret;
|
||||
|
||||
ret = ltc2497_wait_conv(st);
|
||||
if (ret < 0)
|
||||
return ret;
|
||||
|
||||
if (ret || st->addr_prev != address) {
|
||||
ret = i2c_smbus_write_byte(st->client,
|
||||
LTC2497_ENABLE | address);
|
||||
if (ret < 0)
|
||||
return ret;
|
||||
st->addr_prev = address;
|
||||
if (msleep_interruptible(LTC2497_CONVERSION_TIME_MS))
|
||||
return -ERESTARTSYS;
|
||||
}
|
||||
ret = i2c_master_recv(client, (char *)&st->buf, 3);
|
||||
if (ret < 0) {
|
||||
dev_err(&client->dev, "i2c_master_recv failed\n");
|
||||
return ret;
|
||||
}
|
||||
st->time_prev = ktime_get();
|
||||
|
||||
/* convert and shift the result,
|
||||
* and finally convert from offset binary to signed integer
|
||||
*/
|
||||
*val = (be32_to_cpu(st->buf) >> 14) - (1 << 17);
|
||||
|
||||
return ret;
|
||||
}
|
||||
|
||||
static int ltc2497_read_raw(struct iio_dev *indio_dev,
|
||||
struct iio_chan_spec const *chan,
|
||||
int *val, int *val2, long mask)
|
||||
{
|
||||
struct ltc2497_st *st = iio_priv(indio_dev);
|
||||
int ret;
|
||||
|
||||
switch (mask) {
|
||||
case IIO_CHAN_INFO_RAW:
|
||||
mutex_lock(&indio_dev->mlock);
|
||||
ret = ltc2497_read(st, chan->address, val);
|
||||
mutex_unlock(&indio_dev->mlock);
|
||||
if (ret < 0)
|
||||
return ret;
|
||||
|
||||
return IIO_VAL_INT;
|
||||
|
||||
case IIO_CHAN_INFO_SCALE:
|
||||
ret = regulator_get_voltage(st->ref);
|
||||
if (ret < 0)
|
||||
return ret;
|
||||
|
||||
*val = ret / 1000;
|
||||
*val2 = 17;
|
||||
|
||||
return IIO_VAL_FRACTIONAL_LOG2;
|
||||
|
||||
default:
|
||||
return -EINVAL;
|
||||
}
|
||||
}
|
||||
|
||||
#define LTC2497_CHAN(_chan, _addr) { \
|
||||
.type = IIO_VOLTAGE, \
|
||||
.indexed = 1, \
|
||||
.channel = (_chan), \
|
||||
.address = (_addr | (_chan / 2) | ((_chan & 1) ? LTC2497_SIGN : 0)), \
|
||||
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
|
||||
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
|
||||
}
|
||||
|
||||
#define LTC2497_CHAN_DIFF(_chan, _addr) { \
|
||||
.type = IIO_VOLTAGE, \
|
||||
.indexed = 1, \
|
||||
.channel = (_chan) * 2 + ((_addr) & LTC2497_SIGN ? 1 : 0), \
|
||||
.channel2 = (_chan) * 2 + ((_addr) & LTC2497_SIGN ? 0 : 1),\
|
||||
.address = (_addr | _chan), \
|
||||
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
|
||||
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
|
||||
.differential = 1, \
|
||||
}
|
||||
|
||||
static const struct iio_chan_spec ltc2497_channel[] = {
|
||||
LTC2497_CHAN(0, LTC2497_SGL),
|
||||
LTC2497_CHAN(1, LTC2497_SGL),
|
||||
LTC2497_CHAN(2, LTC2497_SGL),
|
||||
LTC2497_CHAN(3, LTC2497_SGL),
|
||||
LTC2497_CHAN(4, LTC2497_SGL),
|
||||
LTC2497_CHAN(5, LTC2497_SGL),
|
||||
LTC2497_CHAN(6, LTC2497_SGL),
|
||||
LTC2497_CHAN(7, LTC2497_SGL),
|
||||
LTC2497_CHAN(8, LTC2497_SGL),
|
||||
LTC2497_CHAN(9, LTC2497_SGL),
|
||||
LTC2497_CHAN(10, LTC2497_SGL),
|
||||
LTC2497_CHAN(11, LTC2497_SGL),
|
||||
LTC2497_CHAN(12, LTC2497_SGL),
|
||||
LTC2497_CHAN(13, LTC2497_SGL),
|
||||
LTC2497_CHAN(14, LTC2497_SGL),
|
||||
LTC2497_CHAN(15, LTC2497_SGL),
|
||||
LTC2497_CHAN_DIFF(0, LTC2497_DIFF),
|
||||
LTC2497_CHAN_DIFF(1, LTC2497_DIFF),
|
||||
LTC2497_CHAN_DIFF(2, LTC2497_DIFF),
|
||||
LTC2497_CHAN_DIFF(3, LTC2497_DIFF),
|
||||
LTC2497_CHAN_DIFF(4, LTC2497_DIFF),
|
||||
LTC2497_CHAN_DIFF(5, LTC2497_DIFF),
|
||||
LTC2497_CHAN_DIFF(6, LTC2497_DIFF),
|
||||
LTC2497_CHAN_DIFF(7, LTC2497_DIFF),
|
||||
LTC2497_CHAN_DIFF(0, LTC2497_DIFF | LTC2497_SIGN),
|
||||
LTC2497_CHAN_DIFF(1, LTC2497_DIFF | LTC2497_SIGN),
|
||||
LTC2497_CHAN_DIFF(2, LTC2497_DIFF | LTC2497_SIGN),
|
||||
LTC2497_CHAN_DIFF(3, LTC2497_DIFF | LTC2497_SIGN),
|
||||
LTC2497_CHAN_DIFF(4, LTC2497_DIFF | LTC2497_SIGN),
|
||||
LTC2497_CHAN_DIFF(5, LTC2497_DIFF | LTC2497_SIGN),
|
||||
LTC2497_CHAN_DIFF(6, LTC2497_DIFF | LTC2497_SIGN),
|
||||
LTC2497_CHAN_DIFF(7, LTC2497_DIFF | LTC2497_SIGN),
|
||||
};
|
||||
|
||||
static const struct iio_info ltc2497_info = {
|
||||
.read_raw = ltc2497_read_raw,
|
||||
.driver_module = THIS_MODULE,
|
||||
};
|
||||
|
||||
static int ltc2497_probe(struct i2c_client *client,
|
||||
const struct i2c_device_id *id)
|
||||
{
|
||||
struct iio_dev *indio_dev;
|
||||
struct ltc2497_st *st;
|
||||
int ret;
|
||||
|
||||
if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C |
|
||||
I2C_FUNC_SMBUS_WRITE_BYTE))
|
||||
return -EOPNOTSUPP;
|
||||
|
||||
indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*st));
|
||||
if (!indio_dev)
|
||||
return -ENOMEM;
|
||||
|
||||
st = iio_priv(indio_dev);
|
||||
i2c_set_clientdata(client, indio_dev);
|
||||
st->client = client;
|
||||
|
||||
indio_dev->dev.parent = &client->dev;
|
||||
indio_dev->name = id->name;
|
||||
indio_dev->info = <c2497_info;
|
||||
indio_dev->modes = INDIO_DIRECT_MODE;
|
||||
indio_dev->channels = ltc2497_channel;
|
||||
indio_dev->num_channels = ARRAY_SIZE(ltc2497_channel);
|
||||
|
||||
st->ref = devm_regulator_get(&client->dev, "vref");
|
||||
if (IS_ERR(st->ref))
|
||||
return PTR_ERR(st->ref);
|
||||
|
||||
ret = regulator_enable(st->ref);
|
||||
if (ret < 0)
|
||||
return ret;
|
||||
|
||||
ret = i2c_smbus_write_byte(st->client, LTC2497_CONFIG_DEFAULT);
|
||||
if (ret < 0)
|
||||
goto err_regulator_disable;
|
||||
|
||||
st->addr_prev = LTC2497_CONFIG_DEFAULT;
|
||||
st->time_prev = ktime_get();
|
||||
|
||||
ret = iio_device_register(indio_dev);
|
||||
if (ret < 0)
|
||||
goto err_regulator_disable;
|
||||
|
||||
return 0;
|
||||
|
||||
err_regulator_disable:
|
||||
regulator_disable(st->ref);
|
||||
|
||||
return ret;
|
||||
}
|
||||
|
||||
static int ltc2497_remove(struct i2c_client *client)
|
||||
{
|
||||
struct iio_dev *indio_dev = i2c_get_clientdata(client);
|
||||
struct ltc2497_st *st = iio_priv(indio_dev);
|
||||
|
||||
iio_device_unregister(indio_dev);
|
||||
regulator_disable(st->ref);
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static const struct i2c_device_id ltc2497_id[] = {
|
||||
{ "ltc2497", 0 },
|
||||
{ }
|
||||
};
|
||||
MODULE_DEVICE_TABLE(i2c, ltc2497_id);
|
||||
|
||||
static const struct of_device_id ltc2497_of_match[] = {
|
||||
{ .compatible = "lltc,ltc2497", },
|
||||
{},
|
||||
};
|
||||
MODULE_DEVICE_TABLE(of, ltc2497_of_match);
|
||||
|
||||
static struct i2c_driver ltc2497_driver = {
|
||||
.driver = {
|
||||
.name = "ltc2497",
|
||||
.of_match_table = of_match_ptr(ltc2497_of_match),
|
||||
},
|
||||
.probe = ltc2497_probe,
|
||||
.remove = ltc2497_remove,
|
||||
.id_table = ltc2497_id,
|
||||
};
|
||||
module_i2c_driver(ltc2497_driver);
|
||||
|
||||
MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
|
||||
MODULE_DESCRIPTION("Linear Technology LTC2497 ADC driver");
|
||||
MODULE_LICENSE("GPL v2");
|
||||
Loading…
Reference in New Issue