The following functions are supported: - write, read potentiometer value - potentiometer scale Datasheet: https://datasheets.maximintegrated.com/en/ds/DS1803.pdf Signed-off-by: Slawomir Stepien <sst@xxxxxxxxx> --- .../bindings/iio/potentiometer/ds1803.txt | 21 +++ drivers/iio/potentiometer/Kconfig | 10 ++ drivers/iio/potentiometer/Makefile | 1 + drivers/iio/potentiometer/ds1803.c | 178 +++++++++++++++++++++ 4 files changed, 210 insertions(+) create mode 100644 Documentation/devicetree/bindings/iio/potentiometer/ds1803.txt create mode 100644 drivers/iio/potentiometer/ds1803.c diff --git a/Documentation/devicetree/bindings/iio/potentiometer/ds1803.txt b/Documentation/devicetree/bindings/iio/potentiometer/ds1803.txt new file mode 100644 index 0000000..df77bf5 --- /dev/null +++ b/Documentation/devicetree/bindings/iio/potentiometer/ds1803.txt @@ -0,0 +1,21 @@ +* Maxim Integrated DS1803 digital potentiometer driver + +The node for this driver must be a child node of a I2C controller, hence +all mandatory properties for your controller must be specified. See directory: + + Documentation/devicetree/bindings/i2c + +for more details. + +Required properties: + - compatible: Must be one of the following, depending on the + model: + "maxim,ds1803-010", + "maxim,ds1803-050", + "maxim,ds1803-100" + +Example: +ds1803: ds1803@1 { + reg = <0x28>; + compatible = "maxim,ds1803-010"; +}; diff --git a/drivers/iio/potentiometer/Kconfig b/drivers/iio/potentiometer/Kconfig index 7ea069b..6acb238 100644 --- a/drivers/iio/potentiometer/Kconfig +++ b/drivers/iio/potentiometer/Kconfig @@ -5,6 +5,16 @@ menu "Digital potentiometers" +config DS1803 + tristate "Maxim Integrated DS1803 Digital Potentiometer driver" + depends on I2C + help + Say yes here to build support for the Maxim Integrated DS1803 + digital potentiomenter chip. + + To compile this driver as a module, choose M here: the + module will be called ds1803. + config MCP4131 tristate "Microchip MCP413X/414X/415X/416X/423X/424X/425X/426X Digital Potentiometer driver" depends on SPI diff --git a/drivers/iio/potentiometer/Makefile b/drivers/iio/potentiometer/Makefile index 91a80f8..6007faa 100644 --- a/drivers/iio/potentiometer/Makefile +++ b/drivers/iio/potentiometer/Makefile @@ -3,6 +3,7 @@ # # When adding new entries keep the list in alphabetical order +obj-$(CONFIG_DS1803) += ds1803.o obj-$(CONFIG_MCP4131) += mcp4131.o obj-$(CONFIG_MCP4531) += mcp4531.o obj-$(CONFIG_TPL0102) += tpl0102.o diff --git a/drivers/iio/potentiometer/ds1803.c b/drivers/iio/potentiometer/ds1803.c new file mode 100644 index 0000000..b5e5b1c --- /dev/null +++ b/drivers/iio/potentiometer/ds1803.c @@ -0,0 +1,178 @@ +/* + * 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/cache.h> +#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_NUM_WIPERS 2 +#define DS1803_MAX_POS 255 +#define DS1803_WRITE(n) (0xA8 | ((n) + 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; + s32 ret; + + switch (mask) { + case IIO_CHAN_INFO_RAW: + ret = i2c_smbus_read_word_swapped(data->client, 0); + if (ret < 0) + return ret; + + /* Get bits for given pot */ + *val = (pot == 0 ? ret >> 8 : ret & 255); + 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; + + 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, + .driver_module = THIS_MODULE, +}; + +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; + + /* Value of two pots is read at the same time */ + if (!i2c_check_functionality(client->adapter, + I2C_FUNC_SMBUS_WORD_DATA)) { + dev_err(dev, "SMBUS Word Data not supported\n"); + return -EOPNOTSUPP; + } + + 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 = DS1803_NUM_WIPERS; + 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@xxxxxxxxx>"); +MODULE_DESCRIPTION("DS1803 digital potentiometer"); +MODULE_LICENSE("GPL v2"); -- 2.7.4 -- To unsubscribe from this list: send the line "unsubscribe linux-iio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
