> The following functions are supported: > - write, read potentiometer value > - potentiometer scale
minor comments below, nice driver > Datasheet: https://datasheets.maximintegrated.com/en/ds/DS1803.pdf > > Signed-off-by: Slawomir Stepien <s...@poczta.fm> > --- > .../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> for what is cache.h needed? > +#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); maybe a #define to explain the name of register 0 > + if (ret < 0) > + return ret; > + > + /* Get bits for given pot */ > + *val = (pot == 0 ? ret >> 8 : ret & 255); often 0xff is used to mask a byte > + 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) check that val2 is 0 or use .write_raw_get_fmt > + 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; 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 <s...@poczta.fm>"); > +MODULE_DESCRIPTION("DS1803 digital potentiometer"); > +MODULE_LICENSE("GPL v2"); > -- Peter Meerwald-Stadler +43-664-2444418 (mobile)
