iio: potentiometer: add driver for Maxim Integrated DS1803 (fbbc5e70) · Commits · e / devices / android_kernel_fairphone_FP4

Documentation/devicetree/bindings/iio/potentiometer/ds1803.txt

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		* 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";
		};

drivers/iio/potentiometer/Kconfig

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		@@ -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

drivers/iio/potentiometer/Makefile

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		@@ -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

drivers/iio/potentiometer/ds1803.c

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		/*
		* 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[indio_dev->num_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,
		.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;

		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");