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// SPDX-License-Identifier: GPL-2.0-only
/*
* Maxim Integrated DS1803 and similar digital potentiometer driver
* Copyright (c) 2016 Slawomir Stepien
* Copyright (c) 2022 Jagath Jog J
*
* Datasheet: https://datasheets.maximintegrated.com/en/ds/DS1803.pdf
* Datasheet: https://datasheets.maximintegrated.com/en/ds/DS3502.pdf
*
* DEVID #Wipers #Positions Resistor Opts (kOhm) i2c address
* ds1803 2 256 10, 50, 100 0101xxx
* ds3502 1 128 10 01010xx
*/
#include <linux/err.h>
#include <linux/export.h>
#include <linux/i2c.h>
#include <linux/iio/iio.h>
#include <linux/module.h>
#include <linux/mod_devicetable.h>
#include <linux/property.h>
#define DS1803_WIPER_0 0xA9
#define DS1803_WIPER_1 0xAA
#define DS3502_WR_IVR 0x00
enum ds1803_type {
DS1803_010,
DS1803_050,
DS1803_100,
DS3502,
};
struct ds1803_cfg {
int wipers;
int avail[3];
int kohms;
const struct iio_chan_spec *channels;
u8 num_channels;
int (*read)(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan, int *val);
};
struct ds1803_data {
struct i2c_client *client;
const struct ds1803_cfg *cfg;
};
#define DS1803_CHANNEL(ch, addr) { \
.type = IIO_RESISTANCE, \
.indexed = 1, \
.output = 1, \
.channel = (ch), \
.address = (addr), \
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
.info_mask_shared_by_type_available = BIT(IIO_CHAN_INFO_RAW), \
}
static const struct iio_chan_spec ds1803_channels[] = {
DS1803_CHANNEL(0, DS1803_WIPER_0),
DS1803_CHANNEL(1, DS1803_WIPER_1),
};
static const struct iio_chan_spec ds3502_channels[] = {
DS1803_CHANNEL(0, DS3502_WR_IVR),
};
static int ds1803_read(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val)
{
struct ds1803_data *data = iio_priv(indio_dev);
int ret;
u8 result[ARRAY_SIZE(ds1803_channels)];
ret = i2c_master_recv(data->client, result, indio_dev->num_channels);
if (ret < 0)
return ret;
*val = result[chan->channel];
return ret;
}
static int ds3502_read(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val)
{
struct ds1803_data *data = iio_priv(indio_dev);
int ret;
ret = i2c_smbus_read_byte_data(data->client, chan->address);
if (ret < 0)
return ret;
*val = ret;
return ret;
}
static const struct ds1803_cfg ds1803_cfg[] = {
[DS1803_010] = {
.wipers = 2,
.avail = { 0, 1, 255 },
.kohms = 10,
.channels = ds1803_channels,
.num_channels = ARRAY_SIZE(ds1803_channels),
.read = ds1803_read,
},
[DS1803_050] = {
.wipers = 2,
.avail = { 0, 1, 255 },
.kohms = 50,
.channels = ds1803_channels,
.num_channels = ARRAY_SIZE(ds1803_channels),
.read = ds1803_read,
},
[DS1803_100] = {
.wipers = 2,
.avail = { 0, 1, 255 },
.kohms = 100,
.channels = ds1803_channels,
.num_channels = ARRAY_SIZE(ds1803_channels),
.read = ds1803_read,
},
[DS3502] = {
.wipers = 1,
.avail = { 0, 1, 127 },
.kohms = 10,
.channels = ds3502_channels,
.num_channels = ARRAY_SIZE(ds3502_channels),
.read = ds3502_read,
},
};
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 ret;
switch (mask) {
case IIO_CHAN_INFO_RAW:
ret = data->cfg->read(indio_dev, chan, val);
if (ret < 0)
return ret;
return IIO_VAL_INT;
case IIO_CHAN_INFO_SCALE:
*val = 1000 * data->cfg->kohms;
*val2 = data->cfg->avail[2]; /* Max wiper position */
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);
u8 addr = chan->address;
int max_pos = data->cfg->avail[2];
if (val2 != 0)
return -EINVAL;
switch (mask) {
case IIO_CHAN_INFO_RAW:
if (val > max_pos || val < 0)
return -EINVAL;
break;
default:
return -EINVAL;
}
return i2c_smbus_write_byte_data(data->client, addr, val);
}
static int ds1803_read_avail(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
const int **vals, int *type,
int *length, long mask)
{
struct ds1803_data *data = iio_priv(indio_dev);
switch (mask) {
case IIO_CHAN_INFO_RAW:
*vals = data->cfg->avail;
*length = ARRAY_SIZE(data->cfg->avail);
*type = IIO_VAL_INT;
return IIO_AVAIL_RANGE;
}
return -EINVAL;
}
static const struct iio_info ds1803_info = {
.read_raw = ds1803_read_raw,
.write_raw = ds1803_write_raw,
.read_avail = ds1803_read_avail,
};
static int ds1803_probe(struct i2c_client *client)
{
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 = i2c_get_match_data(client);
indio_dev->info = &ds1803_info;
indio_dev->channels = data->cfg->channels;
indio_dev->num_channels = data->cfg->num_channels;
indio_dev->name = client->name;
return devm_iio_device_register(dev, indio_dev);
}
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] },
{ .compatible = "maxim,ds3502", .data = &ds1803_cfg[DS3502] },
{}
};
MODULE_DEVICE_TABLE(of, ds1803_dt_ids);
static const struct i2c_device_id ds1803_id[] = {
{ "ds1803-010", (kernel_ulong_t)&ds1803_cfg[DS1803_010] },
{ "ds1803-050", (kernel_ulong_t)&ds1803_cfg[DS1803_050] },
{ "ds1803-100", (kernel_ulong_t)&ds1803_cfg[DS1803_100] },
{ "ds3502", (kernel_ulong_t)&ds1803_cfg[DS3502] },
{}
};
MODULE_DEVICE_TABLE(i2c, ds1803_id);
static struct i2c_driver ds1803_driver = {
.driver = {
.name = "ds1803",
.of_match_table = ds1803_dt_ids,
},
.probe = ds1803_probe,
.id_table = ds1803_id,
};
module_i2c_driver(ds1803_driver);
MODULE_AUTHOR("Slawomir Stepien <sst@poczta.fm>");
MODULE_AUTHOR("Jagath Jog J <jagathjog1996@gmail.com>");
MODULE_DESCRIPTION("DS1803 digital potentiometer");
MODULE_LICENSE("GPL v2");
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