diff options
Diffstat (limited to 'drivers/iio/potentiometer/ds1803.c')
| -rw-r--r-- | drivers/iio/potentiometer/ds1803.c | 172 |
1 files changed, 172 insertions, 0 deletions
diff --git a/drivers/iio/potentiometer/ds1803.c b/drivers/iio/potentiometer/ds1803.c new file mode 100644 index 000000000..6bf12c9ec --- /dev/null +++ b/drivers/iio/potentiometer/ds1803.c @@ -0,0 +1,172 @@ +/* + * 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[ARRAY_SIZE(ds1803_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"); |