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linux/drivers/iio/potentiometer/ad5110.c

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// 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) may require the
* transfer buffers to live in their own cache lines.
*/
u8 buf[2] __aligned(IIO_DMA_MINALIGN);
};
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);
#define AD5110_ID_TABLE(_name, cfg) { \
.name = _name, \
.driver_data = (kernel_ulong_t)&ad5110_cfg[cfg], \
}
static const struct i2c_device_id ad5110_id[] = {
AD5110_ID_TABLE("ad5110-10", AD5110_10),
AD5110_ID_TABLE("ad5110-80", AD5110_80),
AD5110_ID_TABLE("ad5112-05", AD5112_05),
AD5110_ID_TABLE("ad5112-10", AD5112_10),
AD5110_ID_TABLE("ad5112-80", AD5112_80),
AD5110_ID_TABLE("ad5114-10", AD5114_10),
AD5110_ID_TABLE("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 = i2c_get_match_data(client);
/* 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 = 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");