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iio: potentiometer: Add driver support for AD5110

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The AD5110/AD5112/AD5114 provide a nonvolatile solution
for 128-/64-/32-position adjustment applications, offering
guaranteed low resistor tolerance errors of ±8% and up to
±6 mA current density.

Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/AD5110_5112_5114.pdf
Signed-off-by: Mugilraj Dhavachelvan <dmugil2000@gmail.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20210814175607.48399-3-dmugil2000@gmail.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
This commit is contained in:
Mugilraj Dhavachelvan 2021-08-14 23:25:40 +05:30 • committed by Jonathan Cameron
parent 88b6509b8d
commit d03a74bfac
4 changed files with 361 additions and 0 deletions
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6
MAINTAINERS
View file

@ -459,6 +459,12 @@ S: Maintained
W: https://parisc.wiki.kernel.org/index.php/AD1889
F: sound/pci/ad1889.*
AD5110 ANALOG DEVICES DIGITAL POTENTIOMETERS DRIVER
M: Mugilraj Dhavachelvan <dmugil2000@gmail.com>
L: linux-iio@vger.kernel.org
S: Supported
F: drivers/iio/potentiometer/ad5110.c
AD525X ANALOG DEVICES DIGITAL POTENTIOMETERS DRIVER
M: Michael Hennerich <michael.hennerich@analog.com>
S: Supported

10
drivers/iio/potentiometer/Kconfig
View file

@ -6,6 +6,16 @@
menu "Digital potentiometers"
config AD5110
tristate "Analog Devices AD5110 and similar Digital Potentiometer driver"
depends on I2C
help
Say yes here to build support for the Analog Devices AD5110, AD5112
and AD5114 digital potentiometer chip.
To compile this driver as a module, choose M here: the
module will be called ad5110.
config AD5272
tristate "Analog Devices AD5272 and similar Digital Potentiometer driver"
depends on I2C

1
drivers/iio/potentiometer/Makefile
View file

@ -4,6 +4,7 @@
#
# When adding new entries keep the list in alphabetical order
obj-$(CONFIG_AD5110) += ad5110.o
obj-$(CONFIG_AD5272) += ad5272.o
obj-$(CONFIG_DS1803) += ds1803.o
obj-$(CONFIG_MAX5432) += max5432.o

344
drivers/iio/potentiometer/ad5110.c Normal file
View file

@ -0,0 +1,344 @@
// SPDX-License-Identifier: GPL-2.0+
/*
* Analog Devices AD5110 digital potentiometer driver
*
* Copyright (C) 2021 Mugilraj Dhavachelvan <dmugil2000@gmail.com>
*
* Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/AD5110_5112_5114.pdf
*/
#include <linux/bitfield.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/i2c.h>
#include <linux/module.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
/* AD5110 commands */
#define AD5110_EEPROM_WR 1
#define AD5110_RDAC_WR 2
#define AD5110_SHUTDOWN 3
#define AD5110_RESET 4
#define AD5110_RDAC_RD 5
#define AD5110_EEPROM_RD 6
/* AD5110_EEPROM_RD data */
#define AD5110_WIPER_POS 0
#define AD5110_RESISTOR_TOL 1
#define AD5110_WIPER_RESISTANCE 70
struct ad5110_cfg {
int max_pos;
int kohms;
int shift;
};
enum ad5110_type {
AD5110_10,
AD5110_80,
AD5112_05,
AD5112_10,
AD5112_80,
AD5114_10,
AD5114_80,
};
static const struct ad5110_cfg ad5110_cfg[] = {
[AD5110_10] = { .max_pos = 128, .kohms = 10 },
[AD5110_80] = { .max_pos = 128, .kohms = 80 },
[AD5112_05] = { .max_pos = 64, .kohms = 5, .shift = 1 },
[AD5112_10] = { .max_pos = 64, .kohms = 10, .shift = 1 },
[AD5112_80] = { .max_pos = 64, .kohms = 80, .shift = 1 },
[AD5114_10] = { .max_pos = 32, .kohms = 10, .shift = 2 },
[AD5114_80] = { .max_pos = 32, .kohms = 80, .shift = 2 },
};
struct ad5110_data {
struct i2c_client *client;
s16 tol; /* resistor tolerance */
bool enable;
struct mutex lock;
const struct ad5110_cfg *cfg;
/*
* DMA (thus cache coherency maintenance) requires the
* transfer buffers to live in their own cache lines.
*/
u8 buf[2] ____cacheline_aligned;
};
static const struct iio_chan_spec ad5110_channels[] = {
{
.type = IIO_RESISTANCE,
.output = 1,
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_OFFSET) |
BIT(IIO_CHAN_INFO_SCALE) | BIT(IIO_CHAN_INFO_ENABLE),
},
};
static int ad5110_read(struct ad5110_data *data, u8 cmd, int *val)
{
int ret;
mutex_lock(&data->lock);
data->buf[0] = cmd;
data->buf[1] = *val;
ret = i2c_master_send_dmasafe(data->client, data->buf, sizeof(data->buf));
if (ret < 0) {
goto error;
} else if (ret != sizeof(data->buf)) {
ret = -EIO;
goto error;
}
ret = i2c_master_recv_dmasafe(data->client, data->buf, 1);
if (ret < 0) {
goto error;
} else if (ret != 1) {
ret = -EIO;
goto error;
}
*val = data->buf[0];
ret = 0;
error:
mutex_unlock(&data->lock);
return ret;
}
static int ad5110_write(struct ad5110_data *data, u8 cmd, u8 val)
{
int ret;
mutex_lock(&data->lock);
data->buf[0] = cmd;
data->buf[1] = val;
ret = i2c_master_send_dmasafe(data->client, data->buf, sizeof(data->buf));
if (ret < 0) {
goto error;
} else if (ret != sizeof(data->buf)) {
ret = -EIO;
goto error;
}
ret = 0;
error:
mutex_unlock(&data->lock);
return ret;
}
static int ad5110_resistor_tol(struct ad5110_data *data, u8 cmd, int val)
{
int ret;
ret = ad5110_read(data, cmd, &val);
if (ret)
return ret;
data->tol = data->cfg->kohms * (val & GENMASK(6, 0)) * 10 / 8;
if (!(val & BIT(7)))
data->tol *= -1;
return 0;
}
static ssize_t store_eeprom_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct iio_dev *indio_dev = dev_to_iio_dev(dev);
struct ad5110_data *data = iio_priv(indio_dev);
int val = AD5110_WIPER_POS;
int ret;
ret = ad5110_read(data, AD5110_EEPROM_RD, &val);
if (ret)
return ret;
val = val >> data->cfg->shift;
return iio_format_value(buf, IIO_VAL_INT, 1, &val);
}
static ssize_t store_eeprom_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t len)
{
struct iio_dev *indio_dev = dev_to_iio_dev(dev);
struct ad5110_data *data = iio_priv(indio_dev);
int ret;
ret = ad5110_write(data, AD5110_EEPROM_WR, 0);
if (ret) {
dev_err(&data->client->dev, "RDAC to EEPROM write failed\n");
return ret;
}
/* The storing of EEPROM data takes approximately 18 ms. */
msleep(20);
return len;
}
static IIO_DEVICE_ATTR_RW(store_eeprom, 0);
static struct attribute *ad5110_attributes[] = {
&iio_dev_attr_store_eeprom.dev_attr.attr,
NULL
};
static const struct attribute_group ad5110_attribute_group = {
.attrs = ad5110_attributes,
};
static int ad5110_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val, int *val2, long mask)
{
struct ad5110_data *data = iio_priv(indio_dev);
int ret;
switch (mask) {
case IIO_CHAN_INFO_RAW:
ret = ad5110_read(data, AD5110_RDAC_RD, val);
if (ret)
return ret;
*val = *val >> data->cfg->shift;
return IIO_VAL_INT;
case IIO_CHAN_INFO_OFFSET:
*val = AD5110_WIPER_RESISTANCE * data->cfg->max_pos;
*val2 = 1000 * data->cfg->kohms + data->tol;
return IIO_VAL_FRACTIONAL;
case IIO_CHAN_INFO_SCALE:
*val = 1000 * data->cfg->kohms + data->tol;
*val2 = data->cfg->max_pos;
return IIO_VAL_FRACTIONAL;
case IIO_CHAN_INFO_ENABLE:
*val = data->enable;
return IIO_VAL_INT;
default:
return -EINVAL;
}
}
static int ad5110_write_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int val, int val2, long mask)
{
struct ad5110_data *data = iio_priv(indio_dev);
int ret;
switch (mask) {
case IIO_CHAN_INFO_RAW:
if (val > data->cfg->max_pos || val < 0)
return -EINVAL;
return ad5110_write(data, AD5110_RDAC_WR, val << data->cfg->shift);
case IIO_CHAN_INFO_ENABLE:
if (val < 0 || val > 1)
return -EINVAL;
if (data->enable == val)
return 0;
ret = ad5110_write(data, AD5110_SHUTDOWN, val ? 0 : 1);
if (ret)
return ret;
data->enable = val;
return 0;
default:
return -EINVAL;
}
}
static const struct iio_info ad5110_info = {
.read_raw = ad5110_read_raw,
.write_raw = ad5110_write_raw,
.attrs = &ad5110_attribute_group,
};
#define AD5110_COMPATIBLE(of_compatible, cfg) { \
.compatible = of_compatible, \
.data = &ad5110_cfg[cfg], \
}
static const struct of_device_id ad5110_of_match[] = {
AD5110_COMPATIBLE("adi,ad5110-10", AD5110_10),
AD5110_COMPATIBLE("adi,ad5110-80", AD5110_80),
AD5110_COMPATIBLE("adi,ad5112-05", AD5112_05),
AD5110_COMPATIBLE("adi,ad5112-10", AD5112_10),
AD5110_COMPATIBLE("adi,ad5112-80", AD5112_80),
AD5110_COMPATIBLE("adi,ad5114-10", AD5114_10),
AD5110_COMPATIBLE("adi,ad5114-80", AD5114_80),
{ }
};
MODULE_DEVICE_TABLE(of, ad5110_of_match);
static const struct i2c_device_id ad5110_id[] = {
{ "ad5110-10", AD5110_10 },
{ "ad5110-80", AD5110_80 },
{ "ad5112-05", AD5112_05 },
{ "ad5112-10", AD5112_10 },
{ "ad5112-80", AD5112_80 },
{ "ad5114-10", AD5114_10 },
{ "ad5114-80", AD5114_80 },
{ }
};
MODULE_DEVICE_TABLE(i2c, ad5110_id);
static int ad5110_probe(struct i2c_client *client)
{
struct device *dev = &client->dev;
struct iio_dev *indio_dev;
struct ad5110_data *data;
int ret;
indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
if (!indio_dev)
return -ENOMEM;
data = iio_priv(indio_dev);
data->client = client;
mutex_init(&data->lock);
data->enable = 1;
data->cfg = device_get_match_data(dev);
/* refresh RDAC register with EEPROM */
ret = ad5110_write(data, AD5110_RESET, 0);
if (ret) {
dev_err(dev, "Refresh RDAC with EEPROM failed\n");
return ret;
}
ret = ad5110_resistor_tol(data, AD5110_EEPROM_RD, AD5110_RESISTOR_TOL);
if (ret) {
dev_err(dev, "Read resistor tolerance failed\n");
return ret;
}
indio_dev->modes = INDIO_DIRECT_MODE;
indio_dev->info = &ad5110_info;
indio_dev->channels = ad5110_channels;
indio_dev->num_channels = ARRAY_SIZE(ad5110_channels);
indio_dev->name = client->name;
return devm_iio_device_register(dev, indio_dev);
}
static struct i2c_driver ad5110_driver = {
.driver = {
.name = "ad5110",
.of_match_table = ad5110_of_match,
},
.probe_new = ad5110_probe,
.id_table = ad5110_id,
};
module_i2c_driver(ad5110_driver);
MODULE_AUTHOR("Mugilraj Dhavachelvan <dmugil2000@gmail.com>");
MODULE_DESCRIPTION("AD5110 digital potentiometer");
MODULE_LICENSE("GPL v2");