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/*
* Maxim Integrated DS1803 digital potentiometer driver
* Copyright (c) 2016 Slawomir Stepien
*
* Datasheet: https://datasheets.maximintegrated.com/en/ds/DS1803.pdf
*
* DEVID #Wipers #Positions Resistor Opts (kOhm) i2c address
* ds1803 2 256 10, 50, 100 0101xxx
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 as published by
* the Free Software Foundation.
*/
#include <linux/err.h>
#include <linux/export.h>
#include <linux/i2c.h>
#include <linux/iio/iio.h>
#include <linux/module.h>
#include <linux/of.h>
#define DS1803_MAX_POS 255
#define DS1803_WRITE(chan) (0xa8 | ((chan) + 1))
enum ds1803_type {
DS1803_010,
DS1803_050,
DS1803_100,
};
struct ds1803_cfg {
int kohms;
};
static const struct ds1803_cfg ds1803_cfg[] = {
[DS1803_010] = { .kohms = 10, },
[DS1803_050] = { .kohms = 50, },
[DS1803_100] = { .kohms = 100, },
};
struct ds1803_data {
struct i2c_client *client;
const struct ds1803_cfg *cfg;
};
#define DS1803_CHANNEL(ch) { \
.type = IIO_RESISTANCE, \
.indexed = 1, \
.output = 1, \
.channel = (ch), \
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
}
static const struct iio_chan_spec ds1803_channels[] = {
DS1803_CHANNEL(0),
DS1803_CHANNEL(1),
};
static int ds1803_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val, int *val2, long mask)
{
struct ds1803_data *data = iio_priv(indio_dev);
int pot = chan->channel;
int ret;
u8 result[indio_dev->num_channels];
switch (mask) {
case IIO_CHAN_INFO_RAW:
ret = i2c_master_recv(data->client, result,
indio_dev->num_channels);
if (ret < 0)
return ret;
*val = result[pot];
return IIO_VAL_INT;
case IIO_CHAN_INFO_SCALE:
*val = 1000 * data->cfg->kohms;
*val2 = DS1803_MAX_POS;
return IIO_VAL_FRACTIONAL;
}
return -EINVAL;
}
static int ds1803_write_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int val, int val2, long mask)
{
struct ds1803_data *data = iio_priv(indio_dev);
int pot = chan->channel;
if (val2 != 0)
return -EINVAL;
switch (mask) {
case IIO_CHAN_INFO_RAW:
if (val > DS1803_MAX_POS || val < 0)
return -EINVAL;
break;
default:
return -EINVAL;
}
return i2c_smbus_write_byte_data(data->client, DS1803_WRITE(pot), val);
}
static const struct iio_info ds1803_info = {
.read_raw = ds1803_read_raw,
.write_raw = ds1803_write_raw,
};
static int ds1803_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct device *dev = &client->dev;
struct ds1803_data *data;
struct iio_dev *indio_dev;
indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
if (!indio_dev)
return -ENOMEM;
i2c_set_clientdata(client, indio_dev);
data = iio_priv(indio_dev);
data->client = client;
data->cfg = &ds1803_cfg[id->driver_data];
indio_dev->dev.parent = dev;
indio_dev->info = &ds1803_info;
indio_dev->channels = ds1803_channels;
indio_dev->num_channels = ARRAY_SIZE(ds1803_channels);
indio_dev->name = client->name;
return devm_iio_device_register(dev, indio_dev);
}
#if defined(CONFIG_OF)
static const struct of_device_id ds1803_dt_ids[] = {
{ .compatible = "maxim,ds1803-010", .data = &ds1803_cfg[DS1803_010] },
{ .compatible = "maxim,ds1803-050", .data = &ds1803_cfg[DS1803_050] },
{ .compatible = "maxim,ds1803-100", .data = &ds1803_cfg[DS1803_100] },
{}
};
MODULE_DEVICE_TABLE(of, ds1803_dt_ids);
#endif /* CONFIG_OF */
static const struct i2c_device_id ds1803_id[] = {
{ "ds1803-010", DS1803_010 },
{ "ds1803-050", DS1803_050 },
{ "ds1803-100", DS1803_100 },
{}
};
MODULE_DEVICE_TABLE(i2c, ds1803_id);
static struct i2c_driver ds1803_driver = {
.driver = {
.name = "ds1803",
.of_match_table = of_match_ptr(ds1803_dt_ids),
},
.probe = ds1803_probe,
.id_table = ds1803_id,
};
module_i2c_driver(ds1803_driver);
MODULE_AUTHOR("Slawomir Stepien <sst@poczta.fm>");
MODULE_DESCRIPTION("DS1803 digital potentiometer");
MODULE_LICENSE("GPL v2");
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