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