diff options
Diffstat (limited to 'drivers/iio/potentiometer/ds1803.c')
| -rw-r--r-- | drivers/iio/potentiometer/ds1803.c | 263 |
1 files changed, 263 insertions, 0 deletions
diff --git a/drivers/iio/potentiometer/ds1803.c b/drivers/iio/potentiometer/ds1803.c new file mode 100644 index 000000000..5c212ed7a --- /dev/null +++ b/drivers/iio/potentiometer/ds1803.c @@ -0,0 +1,263 @@ +// 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, 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 = device_get_match_data(dev); + if (!data->cfg) + data->cfg = &ds1803_cfg[id->driver_data]; + + 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", DS1803_010 }, + { "ds1803-050", DS1803_050 }, + { "ds1803-100", DS1803_100 }, + { "ds3502", 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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