drivers/iio/potentiometer/ad5110.c - linux/kernel/git/paulmck/linux-rcu - Git at Google

 // SPDX-License-Identifier: GPL-2.0+
 /*
  * Analog Devices AD5110 digital potentiometer driver
  *
  * Copyright (C) 2021 Mugilraj Dhavachelvan <dmugil2000@gmail.com>
  *
  * Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/AD5110_5112_5114.pdf
  */

 #include <linux/bitfield.h>
 #include <linux/delay.h>
 #include <linux/device.h>
 #include <linux/i2c.h>
 #include <linux/module.h>

 #include <linux/iio/iio.h>
 #include <linux/iio/sysfs.h>

 /* AD5110 commands */
 #define AD5110_EEPROM_WR	1
 #define AD5110_RDAC_WR		2
 #define AD5110_SHUTDOWN	3
 #define AD5110_RESET		4
 #define AD5110_RDAC_RD		5
 #define AD5110_EEPROM_RD	6

 /* AD5110_EEPROM_RD data */
 #define AD5110_WIPER_POS	0
 #define AD5110_RESISTOR_TOL	1

 #define AD5110_WIPER_RESISTANCE	70

 struct ad5110_cfg {
 	int max_pos;
 	int kohms;
 	int shift;
 };

 enum ad5110_type {
 	AD5110_10,
 	AD5110_80,
 	AD5112_05,
 	AD5112_10,
 	AD5112_80,
 	AD5114_10,
 	AD5114_80,
 };

 static const struct ad5110_cfg ad5110_cfg[] = {
 	[AD5110_10] = { .max_pos = 128, .kohms = 10 },
 	[AD5110_80] = { .max_pos = 128, .kohms = 80 },
 	[AD5112_05] = { .max_pos = 64, .kohms = 5, .shift = 1 },
 	[AD5112_10] = { .max_pos = 64, .kohms = 10, .shift = 1 },
 	[AD5112_80] = { .max_pos = 64, .kohms = 80, .shift = 1 },
 	[AD5114_10] = { .max_pos = 32, .kohms = 10, .shift = 2 },
 	[AD5114_80] = { .max_pos = 32, .kohms = 80, .shift = 2 },
 };

 struct ad5110_data {
 	struct i2c_client       *client;
 	s16			tol;		/* resistor tolerance */
 	bool			enable;
 	struct mutex            lock;
 	const struct ad5110_cfg	*cfg;
 	/*
 	 * DMA (thus cache coherency maintenance) may require the
 	 * transfer buffers to live in their own cache lines.
 	 */
 	u8			buf[2] __aligned(IIO_DMA_MINALIGN);
 };

 static const struct iio_chan_spec ad5110_channels[] = {
 	{
 		.type = IIO_RESISTANCE,
 		.output = 1,
 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_OFFSET) |
 					BIT(IIO_CHAN_INFO_SCALE) | BIT(IIO_CHAN_INFO_ENABLE),
 	},
 };

 static int ad5110_read(struct ad5110_data *data, u8 cmd, int *val)
 {
 	int ret;

 	mutex_lock(&data->lock);
 	data->buf[0] = cmd;
 	data->buf[1] = *val;

 	ret = i2c_master_send_dmasafe(data->client, data->buf, sizeof(data->buf));
 	if (ret < 0) {
 		goto error;
 	} else if (ret != sizeof(data->buf)) {
 		ret = -EIO;
 		goto error;
 	}

 	ret = i2c_master_recv_dmasafe(data->client, data->buf, 1);
 	if (ret < 0) {
 		goto error;
 	} else if (ret != 1) {
 		ret = -EIO;
 		goto error;
 	}

 	*val = data->buf[0];
 	ret = 0;

 error:
 	mutex_unlock(&data->lock);
 	return ret;
 }

 static int ad5110_write(struct ad5110_data *data, u8 cmd, u8 val)
 {
 	int ret;

 	mutex_lock(&data->lock);
 	data->buf[0] = cmd;
 	data->buf[1] = val;

 	ret = i2c_master_send_dmasafe(data->client, data->buf, sizeof(data->buf));
 	if (ret < 0) {
 		goto error;
 	} else if (ret != sizeof(data->buf)) {
 		ret = -EIO;
 		goto error;
 	}

 	ret = 0;

 error:
 	mutex_unlock(&data->lock);
 	return ret;
 }

 static int ad5110_resistor_tol(struct ad5110_data *data, u8 cmd, int val)
 {
 	int ret;

 	ret = ad5110_read(data, cmd, &val);
 	if (ret)
 		return ret;

 	data->tol = data->cfg->kohms * (val & GENMASK(6, 0)) * 10 / 8;
 	if (!(val & BIT(7)))
 		data->tol *= -1;

 	return 0;
 }

 static ssize_t store_eeprom_show(struct device *dev,
 				  struct device_attribute *attr,
 				  char *buf)
 {
 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
 	struct ad5110_data *data = iio_priv(indio_dev);
 	int val = AD5110_WIPER_POS;
 	int ret;

 	ret = ad5110_read(data, AD5110_EEPROM_RD, &val);
 	if (ret)
 		return ret;

 	val = val >> data->cfg->shift;
 	return iio_format_value(buf, IIO_VAL_INT, 1, &val);
 }

 static ssize_t store_eeprom_store(struct device *dev,
 				   struct device_attribute *attr,
 				   const char *buf, size_t len)
 {
 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
 	struct ad5110_data *data = iio_priv(indio_dev);
 	int ret;

 	ret = ad5110_write(data, AD5110_EEPROM_WR, 0);
 	if (ret) {
 		dev_err(&data->client->dev, "RDAC to EEPROM write failed\n");
 		return ret;
 	}

 	/* The storing of EEPROM data takes approximately 18 ms. */
 	msleep(20);

 	return len;
 }

 static IIO_DEVICE_ATTR_RW(store_eeprom, 0);

 static struct attribute *ad5110_attributes[] = {
 	&iio_dev_attr_store_eeprom.dev_attr.attr,
 	NULL
 };

 static const struct attribute_group ad5110_attribute_group = {
 	.attrs = ad5110_attributes,
 };

 static int ad5110_read_raw(struct iio_dev *indio_dev,
 			   struct iio_chan_spec const *chan,
 			   int *val, int *val2, long mask)
 {
 	struct ad5110_data *data = iio_priv(indio_dev);
 	int ret;

 	switch (mask) {
 	case IIO_CHAN_INFO_RAW:
 		ret = ad5110_read(data, AD5110_RDAC_RD, val);
 		if (ret)
 			return ret;

 		*val = *val >> data->cfg->shift;
 		return IIO_VAL_INT;
 	case IIO_CHAN_INFO_OFFSET:
 		*val = AD5110_WIPER_RESISTANCE * data->cfg->max_pos;
 		*val2 = 1000 * data->cfg->kohms + data->tol;
 		return IIO_VAL_FRACTIONAL;
 	case IIO_CHAN_INFO_SCALE:
 		*val = 1000 * data->cfg->kohms + data->tol;
 		*val2 = data->cfg->max_pos;
 		return IIO_VAL_FRACTIONAL;
 	case IIO_CHAN_INFO_ENABLE:
 		*val = data->enable;
 		return IIO_VAL_INT;
 	default:
 		return -EINVAL;
 	}
 }

 static int ad5110_write_raw(struct iio_dev *indio_dev,
 			    struct iio_chan_spec const *chan,
 			    int val, int val2, long mask)
 {
 	struct ad5110_data *data = iio_priv(indio_dev);
 	int ret;

 	switch (mask) {
 	case IIO_CHAN_INFO_RAW:
 		if (val > data->cfg->max_pos || val < 0)
 			return -EINVAL;

 		return ad5110_write(data, AD5110_RDAC_WR, val << data->cfg->shift);
 	case IIO_CHAN_INFO_ENABLE:
 		if (val < 0 || val > 1)
 			return -EINVAL;
 		if (data->enable == val)
 			return 0;
 		ret = ad5110_write(data, AD5110_SHUTDOWN, val ? 0 : 1);
 		if (ret)
 			return ret;
 		data->enable = val;
 		return 0;
 	default:
 		return -EINVAL;
 	}
 }

 static const struct iio_info ad5110_info = {
 	.read_raw = ad5110_read_raw,
 	.write_raw = ad5110_write_raw,
 	.attrs = &ad5110_attribute_group,
 };

 #define AD5110_COMPATIBLE(of_compatible, cfg) {	\
 			.compatible = of_compatible,	\
 			.data = &ad5110_cfg[cfg],	\
 }

 static const struct of_device_id ad5110_of_match[] = {
 	AD5110_COMPATIBLE("adi,ad5110-10", AD5110_10),
 	AD5110_COMPATIBLE("adi,ad5110-80", AD5110_80),
 	AD5110_COMPATIBLE("adi,ad5112-05", AD5112_05),
 	AD5110_COMPATIBLE("adi,ad5112-10", AD5112_10),
 	AD5110_COMPATIBLE("adi,ad5112-80", AD5112_80),
 	AD5110_COMPATIBLE("adi,ad5114-10", AD5114_10),
 	AD5110_COMPATIBLE("adi,ad5114-80", AD5114_80),
 	{ }
 };
 MODULE_DEVICE_TABLE(of, ad5110_of_match);

 static const struct i2c_device_id ad5110_id[] = {
 	{ "ad5110-10", AD5110_10 },
 	{ "ad5110-80", AD5110_80 },
 	{ "ad5112-05", AD5112_05 },
 	{ "ad5112-10", AD5112_10 },
 	{ "ad5112-80", AD5112_80 },
 	{ "ad5114-10", AD5114_10 },
 	{ "ad5114-80", AD5114_80 },
 	{ }
 };
 MODULE_DEVICE_TABLE(i2c, ad5110_id);

 static int ad5110_probe(struct i2c_client *client)
 {
 	struct device *dev = &client->dev;
 	struct iio_dev *indio_dev;
 	struct ad5110_data *data;
 	int ret;

 	indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
 	if (!indio_dev)
 		return -ENOMEM;

 	data = iio_priv(indio_dev);
 	data->client = client;
 	mutex_init(&data->lock);
 	data->enable = 1;
 	data->cfg = device_get_match_data(dev);

 	/* refresh RDAC register with EEPROM */
 	ret = ad5110_write(data, AD5110_RESET, 0);
 	if (ret) {
 		dev_err(dev, "Refresh RDAC with EEPROM failed\n");
 		return ret;
 	}

 	ret = ad5110_resistor_tol(data, AD5110_EEPROM_RD, AD5110_RESISTOR_TOL);
 	if (ret) {
 		dev_err(dev, "Read resistor tolerance failed\n");
 		return ret;
 	}

 	indio_dev->modes = INDIO_DIRECT_MODE;
 	indio_dev->info = &ad5110_info;
 	indio_dev->channels = ad5110_channels;
 	indio_dev->num_channels = ARRAY_SIZE(ad5110_channels);
 	indio_dev->name = client->name;

 	return devm_iio_device_register(dev, indio_dev);
 }

 static struct i2c_driver ad5110_driver = {
 	.driver = {
 		.name	= "ad5110",
 		.of_match_table = ad5110_of_match,
 	},
 	.probe_new	= ad5110_probe,
 	.id_table	= ad5110_id,
 };
 module_i2c_driver(ad5110_driver);

 MODULE_AUTHOR("Mugilraj Dhavachelvan <dmugil2000@gmail.com>");
 MODULE_DESCRIPTION("AD5110 digital potentiometer");
 MODULE_LICENSE("GPL v2");
	// SPDX-License-Identifier: GPL-2.0+
	/*
	* Analog Devices AD5110 digital potentiometer driver
	*
	* Copyright (C) 2021 Mugilraj Dhavachelvan <dmugil2000@gmail.com>
	*
	* Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/AD5110_5112_5114.pdf
	*/

	#include <linux/bitfield.h>
	#include <linux/delay.h>
	#include <linux/device.h>
	#include <linux/i2c.h>
	#include <linux/module.h>

	#include <linux/iio/iio.h>
	#include <linux/iio/sysfs.h>

	/* AD5110 commands */
	#define AD5110_EEPROM_WR 1
	#define AD5110_RDAC_WR 2
	#define AD5110_SHUTDOWN 3
	#define AD5110_RESET 4
	#define AD5110_RDAC_RD 5
	#define AD5110_EEPROM_RD 6

	/* AD5110_EEPROM_RD data */
	#define AD5110_WIPER_POS 0
	#define AD5110_RESISTOR_TOL 1

	#define AD5110_WIPER_RESISTANCE 70

	struct ad5110_cfg {
	int max_pos;
	int kohms;
	int shift;
	};

	enum ad5110_type {
	AD5110_10,
	AD5110_80,
	AD5112_05,
	AD5112_10,
	AD5112_80,
	AD5114_10,
	AD5114_80,
	};

	static const struct ad5110_cfg ad5110_cfg[] = {
	[AD5110_10] = { .max_pos = 128, .kohms = 10 },
	[AD5110_80] = { .max_pos = 128, .kohms = 80 },
	[AD5112_05] = { .max_pos = 64, .kohms = 5, .shift = 1 },
	[AD5112_10] = { .max_pos = 64, .kohms = 10, .shift = 1 },
	[AD5112_80] = { .max_pos = 64, .kohms = 80, .shift = 1 },
	[AD5114_10] = { .max_pos = 32, .kohms = 10, .shift = 2 },
	[AD5114_80] = { .max_pos = 32, .kohms = 80, .shift = 2 },
	};

	struct ad5110_data {
	struct i2c_client *client;
	s16 tol; /* resistor tolerance */
	bool enable;
	struct mutex lock;
	const struct ad5110_cfg *cfg;
	/*
	* DMA (thus cache coherency maintenance) may require the
	* transfer buffers to live in their own cache lines.
	*/
	u8 buf[2] __aligned(IIO_DMA_MINALIGN);
	};

	static const struct iio_chan_spec ad5110_channels[] = {
	{
	.type = IIO_RESISTANCE,
	.output = 1,
	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) \| BIT(IIO_CHAN_INFO_OFFSET) \|
	BIT(IIO_CHAN_INFO_SCALE) \| BIT(IIO_CHAN_INFO_ENABLE),
	},
	};

	static int ad5110_read(struct ad5110_data data, u8 cmd, int val)
	{
	int ret;

	mutex_lock(&data->lock);
	data->buf[0] = cmd;
	data->buf[1] = *val;

	ret = i2c_master_send_dmasafe(data->client, data->buf, sizeof(data->buf));
	if (ret < 0) {
	goto error;
	} else if (ret != sizeof(data->buf)) {
	ret = -EIO;
	goto error;
	}

	ret = i2c_master_recv_dmasafe(data->client, data->buf, 1);
	if (ret < 0) {
	goto error;
	} else if (ret != 1) {
	ret = -EIO;
	goto error;
	}

	*val = data->buf[0];
	ret = 0;

	error:
	mutex_unlock(&data->lock);
	return ret;
	}

	static int ad5110_write(struct ad5110_data *data, u8 cmd, u8 val)
	{
	int ret;

	mutex_lock(&data->lock);
	data->buf[0] = cmd;
	data->buf[1] = val;

	ret = i2c_master_send_dmasafe(data->client, data->buf, sizeof(data->buf));
	if (ret < 0) {
	goto error;
	} else if (ret != sizeof(data->buf)) {
	ret = -EIO;
	goto error;
	}

	ret = 0;

	error:
	mutex_unlock(&data->lock);
	return ret;
	}

	static int ad5110_resistor_tol(struct ad5110_data *data, u8 cmd, int val)
	{
	int ret;

	ret = ad5110_read(data, cmd, &val);
	if (ret)
	return ret;

	data->tol = data->cfg->kohms * (val & GENMASK(6, 0)) * 10 / 8;
	if (!(val & BIT(7)))
	data->tol *= -1;

	return 0;
	}

	static ssize_t store_eeprom_show(struct device *dev,
	struct device_attribute *attr,
	char *buf)
	{
	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
	struct ad5110_data *data = iio_priv(indio_dev);
	int val = AD5110_WIPER_POS;
	int ret;

	ret = ad5110_read(data, AD5110_EEPROM_RD, &val);
	if (ret)
	return ret;

	val = val >> data->cfg->shift;
	return iio_format_value(buf, IIO_VAL_INT, 1, &val);
	}

	static ssize_t store_eeprom_store(struct device *dev,
	struct device_attribute *attr,
	const char *buf, size_t len)
	{
	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
	struct ad5110_data *data = iio_priv(indio_dev);
	int ret;

	ret = ad5110_write(data, AD5110_EEPROM_WR, 0);
	if (ret) {
	dev_err(&data->client->dev, "RDAC to EEPROM write failed\n");
	return ret;
	}

	/* The storing of EEPROM data takes approximately 18 ms. */
	msleep(20);

	return len;
	}

	static IIO_DEVICE_ATTR_RW(store_eeprom, 0);

	static struct attribute *ad5110_attributes[] = {
	&iio_dev_attr_store_eeprom.dev_attr.attr,
	NULL
	};

	static const struct attribute_group ad5110_attribute_group = {
	.attrs = ad5110_attributes,
	};

	static int ad5110_read_raw(struct iio_dev *indio_dev,
	struct iio_chan_spec const *chan,
	int val, int val2, long mask)
	{
	struct ad5110_data *data = iio_priv(indio_dev);
	int ret;

	switch (mask) {
	case IIO_CHAN_INFO_RAW:
	ret = ad5110_read(data, AD5110_RDAC_RD, val);
	if (ret)
	return ret;

	val = val >> data->cfg->shift;
	return IIO_VAL_INT;
	case IIO_CHAN_INFO_OFFSET:
	val = AD5110_WIPER_RESISTANCE data->cfg->max_pos;
	val2 = 1000 data->cfg->kohms + data->tol;
	return IIO_VAL_FRACTIONAL;
	case IIO_CHAN_INFO_SCALE:
	val = 1000 data->cfg->kohms + data->tol;
	*val2 = data->cfg->max_pos;
	return IIO_VAL_FRACTIONAL;
	case IIO_CHAN_INFO_ENABLE:
	*val = data->enable;
	return IIO_VAL_INT;
	default:
	return -EINVAL;
	}
	}

	static int ad5110_write_raw(struct iio_dev *indio_dev,
	struct iio_chan_spec const *chan,
	int val, int val2, long mask)
	{
	struct ad5110_data *data = iio_priv(indio_dev);
	int ret;

	switch (mask) {
	case IIO_CHAN_INFO_RAW:
	if (val > data->cfg->max_pos \|\| val < 0)
	return -EINVAL;

	return ad5110_write(data, AD5110_RDAC_WR, val << data->cfg->shift);
	case IIO_CHAN_INFO_ENABLE:
	if (val < 0 \|\| val > 1)
	return -EINVAL;
	if (data->enable == val)
	return 0;
	ret = ad5110_write(data, AD5110_SHUTDOWN, val ? 0 : 1);
	if (ret)
	return ret;
	data->enable = val;
	return 0;
	default:
	return -EINVAL;
	}
	}

	static const struct iio_info ad5110_info = {
	.read_raw = ad5110_read_raw,
	.write_raw = ad5110_write_raw,
	.attrs = &ad5110_attribute_group,
	};

	#define AD5110_COMPATIBLE(of_compatible, cfg) { \
	.compatible = of_compatible, \
	.data = &ad5110_cfg[cfg], \
	}

	static const struct of_device_id ad5110_of_match[] = {
	AD5110_COMPATIBLE("adi,ad5110-10", AD5110_10),
	AD5110_COMPATIBLE("adi,ad5110-80", AD5110_80),
	AD5110_COMPATIBLE("adi,ad5112-05", AD5112_05),
	AD5110_COMPATIBLE("adi,ad5112-10", AD5112_10),
	AD5110_COMPATIBLE("adi,ad5112-80", AD5112_80),
	AD5110_COMPATIBLE("adi,ad5114-10", AD5114_10),
	AD5110_COMPATIBLE("adi,ad5114-80", AD5114_80),
	{ }
	};
	MODULE_DEVICE_TABLE(of, ad5110_of_match);

	static const struct i2c_device_id ad5110_id[] = {
	{ "ad5110-10", AD5110_10 },
	{ "ad5110-80", AD5110_80 },
	{ "ad5112-05", AD5112_05 },
	{ "ad5112-10", AD5112_10 },
	{ "ad5112-80", AD5112_80 },
	{ "ad5114-10", AD5114_10 },
	{ "ad5114-80", AD5114_80 },
	{ }
	};
	MODULE_DEVICE_TABLE(i2c, ad5110_id);

	static int ad5110_probe(struct i2c_client *client)
	{
	struct device *dev = &client->dev;
	struct iio_dev *indio_dev;
	struct ad5110_data *data;
	int ret;

	indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
	if (!indio_dev)
	return -ENOMEM;

	data = iio_priv(indio_dev);
	data->client = client;
	mutex_init(&data->lock);
	data->enable = 1;
	data->cfg = device_get_match_data(dev);

	/* refresh RDAC register with EEPROM */
	ret = ad5110_write(data, AD5110_RESET, 0);
	if (ret) {
	dev_err(dev, "Refresh RDAC with EEPROM failed\n");
	return ret;
	}

	ret = ad5110_resistor_tol(data, AD5110_EEPROM_RD, AD5110_RESISTOR_TOL);
	if (ret) {
	dev_err(dev, "Read resistor tolerance failed\n");
	return ret;
	}

	indio_dev->modes = INDIO_DIRECT_MODE;
	indio_dev->info = &ad5110_info;
	indio_dev->channels = ad5110_channels;
	indio_dev->num_channels = ARRAY_SIZE(ad5110_channels);
	indio_dev->name = client->name;

	return devm_iio_device_register(dev, indio_dev);
	}

	static struct i2c_driver ad5110_driver = {
	.driver = {
	.name = "ad5110",
	.of_match_table = ad5110_of_match,
	},
	.probe_new = ad5110_probe,
	.id_table = ad5110_id,
	};
	module_i2c_driver(ad5110_driver);

	MODULE_AUTHOR("Mugilraj Dhavachelvan <dmugil2000@gmail.com>");
	MODULE_DESCRIPTION("AD5110 digital potentiometer");
	MODULE_LICENSE("GPL v2");