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166 lines
3.8 KiB
166 lines
3.8 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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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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#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/mod_devicetable.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->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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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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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 = 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 <[email protected]>"); |
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MODULE_DESCRIPTION("DS1803 digital potentiometer"); |
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MODULE_LICENSE("GPL v2");
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