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// SPDX-License-Identifier: GPL-2.0
/*
* Industrial I/O driver for Microchip digital potentiometers
* Copyright (c) 2018 Axentia Technologies AB
* Author: Peter Rosin <peda@axentia.se>
*
* Datasheet: http://www.microchip.com/downloads/en/DeviceDoc/22147a.pdf
*
* DEVID #Wipers #Positions Resistor Opts (kOhm)
* mcp4017 1 128 5, 10, 50, 100
* mcp4018 1 128 5, 10, 50, 100
* mcp4019 1 128 5, 10, 50, 100
*/
#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/iio/iio.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_device.h>
#define MCP4018_WIPER_MAX 127
struct mcp4018_cfg {
int kohms;
};
enum mcp4018_type {
MCP4018_502,
MCP4018_103,
MCP4018_503,
MCP4018_104,
};
static const struct mcp4018_cfg mcp4018_cfg[] = {
[MCP4018_502] = { .kohms = 5, },
[MCP4018_103] = { .kohms = 10, },
[MCP4018_503] = { .kohms = 50, },
[MCP4018_104] = { .kohms = 100, },
};
struct mcp4018_data {
struct i2c_client *client;
const struct mcp4018_cfg *cfg;
};
static const struct iio_chan_spec mcp4018_channel = {
.type = IIO_RESISTANCE,
.indexed = 1,
.output = 1,
.channel = 0,
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
};
static int mcp4018_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val, int *val2, long mask)
{
struct mcp4018_data *data = iio_priv(indio_dev);
s32 ret;
switch (mask) {
case IIO_CHAN_INFO_RAW:
ret = i2c_smbus_read_byte(data->client);
if (ret < 0)
return ret;
*val = ret;
return IIO_VAL_INT;
case IIO_CHAN_INFO_SCALE:
*val = 1000 * data->cfg->kohms;
*val2 = MCP4018_WIPER_MAX;
return IIO_VAL_FRACTIONAL;
}
return -EINVAL;
}
static int mcp4018_write_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int val, int val2, long mask)
{
struct mcp4018_data *data = iio_priv(indio_dev);
switch (mask) {
case IIO_CHAN_INFO_RAW:
if (val > MCP4018_WIPER_MAX || val < 0)
return -EINVAL;
break;
default:
return -EINVAL;
}
return i2c_smbus_write_byte(data->client, val);
}
static const struct iio_info mcp4018_info = {
.read_raw = mcp4018_read_raw,
.write_raw = mcp4018_write_raw,
};
static const struct i2c_device_id mcp4018_id[] = {
{ "mcp4017-502", MCP4018_502 },
{ "mcp4017-103", MCP4018_103 },
{ "mcp4017-503", MCP4018_503 },
{ "mcp4017-104", MCP4018_104 },
{ "mcp4018-502", MCP4018_502 },
{ "mcp4018-103", MCP4018_103 },
{ "mcp4018-503", MCP4018_503 },
{ "mcp4018-104", MCP4018_104 },
{ "mcp4019-502", MCP4018_502 },
{ "mcp4019-103", MCP4018_103 },
{ "mcp4019-503", MCP4018_503 },
{ "mcp4019-104", MCP4018_104 },
{}
};
MODULE_DEVICE_TABLE(i2c, mcp4018_id);
#ifdef CONFIG_OF
#define MCP4018_COMPATIBLE(of_compatible, cfg) { \
.compatible = of_compatible, \
.data = &mcp4018_cfg[cfg], \
}
static const struct of_device_id mcp4018_of_match[] = {
MCP4018_COMPATIBLE("microchip,mcp4017-502", MCP4018_502),
MCP4018_COMPATIBLE("microchip,mcp4017-103", MCP4018_103),
MCP4018_COMPATIBLE("microchip,mcp4017-503", MCP4018_503),
MCP4018_COMPATIBLE("microchip,mcp4017-104", MCP4018_104),
MCP4018_COMPATIBLE("microchip,mcp4018-502", MCP4018_502),
MCP4018_COMPATIBLE("microchip,mcp4018-103", MCP4018_103),
MCP4018_COMPATIBLE("microchip,mcp4018-503", MCP4018_503),
MCP4018_COMPATIBLE("microchip,mcp4018-104", MCP4018_104),
MCP4018_COMPATIBLE("microchip,mcp4019-502", MCP4018_502),
MCP4018_COMPATIBLE("microchip,mcp4019-103", MCP4018_103),
MCP4018_COMPATIBLE("microchip,mcp4019-503", MCP4018_503),
MCP4018_COMPATIBLE("microchip,mcp4019-104", MCP4018_104),
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, mcp4018_of_match);
#endif
static int mcp4018_probe(struct i2c_client *client)
{
struct device *dev = &client->dev;
struct mcp4018_data *data;
struct iio_dev *indio_dev;
if (!i2c_check_functionality(client->adapter,
I2C_FUNC_SMBUS_BYTE)) {
dev_err(dev, "SMBUS Byte transfers not supported\n");
return -EOPNOTSUPP;
}
indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
if (!indio_dev)
return -ENOMEM;
data = iio_priv(indio_dev);
i2c_set_clientdata(client, indio_dev);
data->client = client;
data->cfg = of_device_get_match_data(dev);
if (!data->cfg)
data->cfg = &mcp4018_cfg[i2c_match_id(mcp4018_id, client)->driver_data];
indio_dev->info = &mcp4018_info;
indio_dev->channels = &mcp4018_channel;
indio_dev->num_channels = 1;
indio_dev->name = client->name;
return devm_iio_device_register(dev, indio_dev);
}
static struct i2c_driver mcp4018_driver = {
.driver = {
.name = "mcp4018",
.of_match_table = of_match_ptr(mcp4018_of_match),
},
.probe_new = mcp4018_probe,
.id_table = mcp4018_id,
};
module_i2c_driver(mcp4018_driver);
MODULE_AUTHOR("Peter Rosin <peda@axentia.se>");
MODULE_DESCRIPTION("MCP4018 digital potentiometer");
MODULE_LICENSE("GPL v2");
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