drivers/iio/dac/ad7303.c - third_party/kernel - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * AD7303 Digital to analog converters driver
  *
  * Copyright 2013 Analog Devices Inc.
  */

 #include <linux/err.h>
 #include <linux/module.h>
 #include <linux/kernel.h>
 #include <linux/spi/spi.h>
 #include <linux/slab.h>
 #include <linux/sysfs.h>
 #include <linux/regulator/consumer.h>
 #include <linux/of.h>

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

 #include <linux/platform_data/ad7303.h>

 #define AD7303_CFG_EXTERNAL_VREF BIT(15)
 #define AD7303_CFG_POWER_DOWN(ch) BIT(11 + (ch))
 #define AD7303_CFG_ADDR_OFFSET	10

 #define AD7303_CMD_UPDATE_DAC	(0x3 << 8)

 /**
  * struct ad7303_state - driver instance specific data
  * @spi:		the device for this driver instance
  * @config:		cached config register value
  * @dac_cache:		current DAC raw value (chip does not support readback)
  * @data:		spi transfer buffer
  */

 struct ad7303_state {
 	struct spi_device *spi;
 	uint16_t config;
 	uint8_t dac_cache[2];

 	struct regulator *vdd_reg;
 	struct regulator *vref_reg;

 	/*
 	 * DMA (thus cache coherency maintenance) requires the
 	 * transfer buffers to live in their own cache lines.
 	 */
 	__be16 data ____cacheline_aligned;
 };

 static int ad7303_write(struct ad7303_state *st, unsigned int chan,
 	uint8_t val)
 {
 	st->data = cpu_to_be16(AD7303_CMD_UPDATE_DAC |
 		(chan << AD7303_CFG_ADDR_OFFSET) |
 		st->config | val);

 	return spi_write(st->spi, &st->data, sizeof(st->data));
 }

 static ssize_t ad7303_read_dac_powerdown(struct iio_dev *indio_dev,
 	uintptr_t private, const struct iio_chan_spec *chan, char *buf)
 {
 	struct ad7303_state *st = iio_priv(indio_dev);

 	return sprintf(buf, "%d\n", (bool)(st->config &
 		AD7303_CFG_POWER_DOWN(chan->channel)));
 }

 static ssize_t ad7303_write_dac_powerdown(struct iio_dev *indio_dev,
 	 uintptr_t private, const struct iio_chan_spec *chan, const char *buf,
 	 size_t len)
 {
 	struct ad7303_state *st = iio_priv(indio_dev);
 	bool pwr_down;
 	int ret;

 	ret = strtobool(buf, &pwr_down);
 	if (ret)
 		return ret;

 	mutex_lock(&indio_dev->mlock);

 	if (pwr_down)
 		st->config |= AD7303_CFG_POWER_DOWN(chan->channel);
 	else
 		st->config &= ~AD7303_CFG_POWER_DOWN(chan->channel);

 	/* There is no noop cmd which allows us to only update the powerdown
 	 * mode, so just write one of the DAC channels again */
 	ad7303_write(st, chan->channel, st->dac_cache[chan->channel]);

 	mutex_unlock(&indio_dev->mlock);
 	return len;
 }

 static int ad7303_get_vref(struct ad7303_state *st,
 	struct iio_chan_spec const *chan)
 {
 	int ret;

 	if (st->config & AD7303_CFG_EXTERNAL_VREF)
 		return regulator_get_voltage(st->vref_reg);

 	ret = regulator_get_voltage(st->vdd_reg);
 	if (ret < 0)
 		return ret;
 	return ret / 2;
 }

 static int ad7303_read_raw(struct iio_dev *indio_dev,
 	struct iio_chan_spec const *chan, int *val, int *val2, long info)
 {
 	struct ad7303_state *st = iio_priv(indio_dev);
 	int vref_uv;

 	switch (info) {
 	case IIO_CHAN_INFO_RAW:
 		*val = st->dac_cache[chan->channel];
 		return IIO_VAL_INT;
 	case IIO_CHAN_INFO_SCALE:
 		vref_uv = ad7303_get_vref(st, chan);
 		if (vref_uv < 0)
 			return vref_uv;

 		*val = 2 * vref_uv / 1000;
 		*val2 = chan->scan_type.realbits;

 		return IIO_VAL_FRACTIONAL_LOG2;
 	default:
 		break;
 	}
 	return -EINVAL;
 }

 static int ad7303_write_raw(struct iio_dev *indio_dev,
 	struct iio_chan_spec const *chan, int val, int val2, long mask)
 {
 	struct ad7303_state *st = iio_priv(indio_dev);
 	int ret;

 	switch (mask) {
 	case IIO_CHAN_INFO_RAW:
 		if (val >= (1 << chan->scan_type.realbits) || val < 0)
 			return -EINVAL;

 		mutex_lock(&indio_dev->mlock);
 		ret = ad7303_write(st, chan->address, val);
 		if (ret == 0)
 			st->dac_cache[chan->channel] = val;
 		mutex_unlock(&indio_dev->mlock);
 		break;
 	default:
 		ret = -EINVAL;
 	}

 	return ret;
 }

 static const struct iio_info ad7303_info = {
 	.read_raw = ad7303_read_raw,
 	.write_raw = ad7303_write_raw,
 };

 static const struct iio_chan_spec_ext_info ad7303_ext_info[] = {
 	{
 		.name = "powerdown",
 		.read = ad7303_read_dac_powerdown,
 		.write = ad7303_write_dac_powerdown,
 		.shared = IIO_SEPARATE,
 	},
 	{ },
 };

 #define AD7303_CHANNEL(chan) {					\
 	.type = IIO_VOLTAGE,					\
 	.indexed = 1,						\
 	.output = 1,						\
 	.channel = (chan),					\
 	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),		\
 	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),	\
 	.address = (chan),					\
 	.scan_type = {						\
 		.sign = 'u',					\
 		.realbits = 8,					\
 		.storagebits = 8,				\
 		.shift = 0,					\
 	},							\
 	.ext_info = ad7303_ext_info,				\
 }

 static const struct iio_chan_spec ad7303_channels[] = {
 	AD7303_CHANNEL(0),
 	AD7303_CHANNEL(1),
 };

 static int ad7303_probe(struct spi_device *spi)
 {
 	const struct spi_device_id *id = spi_get_device_id(spi);
 	struct iio_dev *indio_dev;
 	struct ad7303_state *st;
 	bool ext_ref;
 	int ret;

 	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
 	if (indio_dev == NULL)
 		return -ENOMEM;

 	st = iio_priv(indio_dev);
 	spi_set_drvdata(spi, indio_dev);

 	st->spi = spi;

 	st->vdd_reg = devm_regulator_get(&spi->dev, "Vdd");
 	if (IS_ERR(st->vdd_reg))
 		return PTR_ERR(st->vdd_reg);

 	ret = regulator_enable(st->vdd_reg);
 	if (ret)
 		return ret;

 	if (spi->dev.of_node) {
 		ext_ref = of_property_read_bool(spi->dev.of_node,
 				"REF-supply");
 	} else {
 		struct ad7303_platform_data *pdata = spi->dev.platform_data;
 		if (pdata && pdata->use_external_ref)
 			ext_ref = true;
 		else
 		    ext_ref = false;
 	}

 	if (ext_ref) {
 		st->vref_reg = devm_regulator_get(&spi->dev, "REF");
 		if (IS_ERR(st->vref_reg)) {
 			ret = PTR_ERR(st->vref_reg);
 			goto err_disable_vdd_reg;
 		}

 		ret = regulator_enable(st->vref_reg);
 		if (ret)
 			goto err_disable_vdd_reg;

 		st->config |= AD7303_CFG_EXTERNAL_VREF;
 	}

 	indio_dev->dev.parent = &spi->dev;
 	indio_dev->name = id->name;
 	indio_dev->info = &ad7303_info;
 	indio_dev->modes = INDIO_DIRECT_MODE;
 	indio_dev->channels = ad7303_channels;
 	indio_dev->num_channels = ARRAY_SIZE(ad7303_channels);

 	ret = iio_device_register(indio_dev);
 	if (ret)
 		goto err_disable_vref_reg;

 	return 0;

 err_disable_vref_reg:
 	if (st->vref_reg)
 		regulator_disable(st->vref_reg);
 err_disable_vdd_reg:
 	regulator_disable(st->vdd_reg);
 	return ret;
 }

 static int ad7303_remove(struct spi_device *spi)
 {
 	struct iio_dev *indio_dev = spi_get_drvdata(spi);
 	struct ad7303_state *st = iio_priv(indio_dev);

 	iio_device_unregister(indio_dev);

 	if (st->vref_reg)
 		regulator_disable(st->vref_reg);
 	regulator_disable(st->vdd_reg);

 	return 0;
 }

 static const struct of_device_id ad7303_spi_of_match[] = {
 	{ .compatible = "adi,ad7303", },
 	{ /* sentinel */ },
 };
 MODULE_DEVICE_TABLE(of, ad7303_spi_of_match);

 static const struct spi_device_id ad7303_spi_ids[] = {
 	{ "ad7303", 0 },
 	{}
 };
 MODULE_DEVICE_TABLE(spi, ad7303_spi_ids);

 static struct spi_driver ad7303_driver = {
 	.driver = {
 		.name = "ad7303",
 		.of_match_table = of_match_ptr(ad7303_spi_of_match),
 	},
 	.probe = ad7303_probe,
 	.remove = ad7303_remove,
 	.id_table = ad7303_spi_ids,
 };
 module_spi_driver(ad7303_driver);

 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
 MODULE_DESCRIPTION("Analog Devices AD7303 DAC driver");
 MODULE_LICENSE("GPL v2");
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* AD7303 Digital to analog converters driver
	*
	* Copyright 2013 Analog Devices Inc.
	*/

	#include <linux/err.h>
	#include <linux/module.h>
	#include <linux/kernel.h>
	#include <linux/spi/spi.h>
	#include <linux/slab.h>
	#include <linux/sysfs.h>
	#include <linux/regulator/consumer.h>
	#include <linux/of.h>

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

	#include <linux/platform_data/ad7303.h>

	#define AD7303_CFG_EXTERNAL_VREF BIT(15)
	#define AD7303_CFG_POWER_DOWN(ch) BIT(11 + (ch))
	#define AD7303_CFG_ADDR_OFFSET 10

	#define AD7303_CMD_UPDATE_DAC (0x3 << 8)

	/**
	* struct ad7303_state - driver instance specific data
	* @spi: the device for this driver instance
	* @config: cached config register value
	* @dac_cache: current DAC raw value (chip does not support readback)
	* @data: spi transfer buffer
	*/

	struct ad7303_state {
	struct spi_device *spi;
	uint16_t config;
	uint8_t dac_cache[2];

	struct regulator *vdd_reg;
	struct regulator *vref_reg;

	/*
	* DMA (thus cache coherency maintenance) requires the
	* transfer buffers to live in their own cache lines.
	*/
	__be16 data ____cacheline_aligned;
	};

	static int ad7303_write(struct ad7303_state *st, unsigned int chan,
	uint8_t val)
	{
	st->data = cpu_to_be16(AD7303_CMD_UPDATE_DAC \|
	(chan << AD7303_CFG_ADDR_OFFSET) \|
	st->config \| val);

	return spi_write(st->spi, &st->data, sizeof(st->data));
	}

	static ssize_t ad7303_read_dac_powerdown(struct iio_dev *indio_dev,
	uintptr_t private, const struct iio_chan_spec chan, char buf)
	{
	struct ad7303_state *st = iio_priv(indio_dev);

	return sprintf(buf, "%d\n", (bool)(st->config &
	AD7303_CFG_POWER_DOWN(chan->channel)));
	}

	static ssize_t ad7303_write_dac_powerdown(struct iio_dev *indio_dev,
	uintptr_t private, const struct iio_chan_spec chan, const char buf,
	size_t len)
	{
	struct ad7303_state *st = iio_priv(indio_dev);
	bool pwr_down;
	int ret;

	ret = strtobool(buf, &pwr_down);
	if (ret)
	return ret;

	mutex_lock(&indio_dev->mlock);

	if (pwr_down)
	st->config \|= AD7303_CFG_POWER_DOWN(chan->channel);
	else
	st->config &= ~AD7303_CFG_POWER_DOWN(chan->channel);

	/* There is no noop cmd which allows us to only update the powerdown
	* mode, so just write one of the DAC channels again */
	ad7303_write(st, chan->channel, st->dac_cache[chan->channel]);

	mutex_unlock(&indio_dev->mlock);
	return len;
	}

	static int ad7303_get_vref(struct ad7303_state *st,
	struct iio_chan_spec const *chan)
	{
	int ret;

	if (st->config & AD7303_CFG_EXTERNAL_VREF)
	return regulator_get_voltage(st->vref_reg);

	ret = regulator_get_voltage(st->vdd_reg);
	if (ret < 0)
	return ret;
	return ret / 2;
	}

	static int ad7303_read_raw(struct iio_dev *indio_dev,
	struct iio_chan_spec const chan, int val, int *val2, long info)
	{
	struct ad7303_state *st = iio_priv(indio_dev);
	int vref_uv;

	switch (info) {
	case IIO_CHAN_INFO_RAW:
	*val = st->dac_cache[chan->channel];
	return IIO_VAL_INT;
	case IIO_CHAN_INFO_SCALE:
	vref_uv = ad7303_get_vref(st, chan);
	if (vref_uv < 0)
	return vref_uv;

	val = 2 vref_uv / 1000;
	*val2 = chan->scan_type.realbits;

	return IIO_VAL_FRACTIONAL_LOG2;
	default:
	break;
	}
	return -EINVAL;
	}

	static int ad7303_write_raw(struct iio_dev *indio_dev,
	struct iio_chan_spec const *chan, int val, int val2, long mask)
	{
	struct ad7303_state *st = iio_priv(indio_dev);
	int ret;

	switch (mask) {
	case IIO_CHAN_INFO_RAW:
	if (val >= (1 << chan->scan_type.realbits) \|\| val < 0)
	return -EINVAL;

	mutex_lock(&indio_dev->mlock);
	ret = ad7303_write(st, chan->address, val);
	if (ret == 0)
	st->dac_cache[chan->channel] = val;
	mutex_unlock(&indio_dev->mlock);
	break;
	default:
	ret = -EINVAL;
	}

	return ret;
	}

	static const struct iio_info ad7303_info = {
	.read_raw = ad7303_read_raw,
	.write_raw = ad7303_write_raw,
	};

	static const struct iio_chan_spec_ext_info ad7303_ext_info[] = {
	{
	.name = "powerdown",
	.read = ad7303_read_dac_powerdown,
	.write = ad7303_write_dac_powerdown,
	.shared = IIO_SEPARATE,
	},
	{ },
	};

	#define AD7303_CHANNEL(chan) { \
	.type = IIO_VOLTAGE, \
	.indexed = 1, \
	.output = 1, \
	.channel = (chan), \
	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
	.address = (chan), \
	.scan_type = { \
	.sign = 'u', \
	.realbits = 8, \
	.storagebits = 8, \
	.shift = 0, \
	}, \
	.ext_info = ad7303_ext_info, \
	}

	static const struct iio_chan_spec ad7303_channels[] = {
	AD7303_CHANNEL(0),
	AD7303_CHANNEL(1),
	};

	static int ad7303_probe(struct spi_device *spi)
	{
	const struct spi_device_id *id = spi_get_device_id(spi);
	struct iio_dev *indio_dev;
	struct ad7303_state *st;
	bool ext_ref;
	int ret;

	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
	if (indio_dev == NULL)
	return -ENOMEM;

	st = iio_priv(indio_dev);
	spi_set_drvdata(spi, indio_dev);

	st->spi = spi;

	st->vdd_reg = devm_regulator_get(&spi->dev, "Vdd");
	if (IS_ERR(st->vdd_reg))
	return PTR_ERR(st->vdd_reg);

	ret = regulator_enable(st->vdd_reg);
	if (ret)
	return ret;

	if (spi->dev.of_node) {
	ext_ref = of_property_read_bool(spi->dev.of_node,
	"REF-supply");
	} else {
	struct ad7303_platform_data *pdata = spi->dev.platform_data;
	if (pdata && pdata->use_external_ref)
	ext_ref = true;
	else
	ext_ref = false;
	}

	if (ext_ref) {
	st->vref_reg = devm_regulator_get(&spi->dev, "REF");
	if (IS_ERR(st->vref_reg)) {
	ret = PTR_ERR(st->vref_reg);
	goto err_disable_vdd_reg;
	}

	ret = regulator_enable(st->vref_reg);
	if (ret)
	goto err_disable_vdd_reg;

	st->config \|= AD7303_CFG_EXTERNAL_VREF;
	}

	indio_dev->dev.parent = &spi->dev;
	indio_dev->name = id->name;
	indio_dev->info = &ad7303_info;
	indio_dev->modes = INDIO_DIRECT_MODE;
	indio_dev->channels = ad7303_channels;
	indio_dev->num_channels = ARRAY_SIZE(ad7303_channels);

	ret = iio_device_register(indio_dev);
	if (ret)
	goto err_disable_vref_reg;

	return 0;

	err_disable_vref_reg:
	if (st->vref_reg)
	regulator_disable(st->vref_reg);
	err_disable_vdd_reg:
	regulator_disable(st->vdd_reg);
	return ret;
	}

	static int ad7303_remove(struct spi_device *spi)
	{
	struct iio_dev *indio_dev = spi_get_drvdata(spi);
	struct ad7303_state *st = iio_priv(indio_dev);

	iio_device_unregister(indio_dev);

	if (st->vref_reg)
	regulator_disable(st->vref_reg);
	regulator_disable(st->vdd_reg);

	return 0;
	}

	static const struct of_device_id ad7303_spi_of_match[] = {
	{ .compatible = "adi,ad7303", },
	{ /* sentinel */ },
	};
	MODULE_DEVICE_TABLE(of, ad7303_spi_of_match);

	static const struct spi_device_id ad7303_spi_ids[] = {
	{ "ad7303", 0 },
	{}
	};
	MODULE_DEVICE_TABLE(spi, ad7303_spi_ids);

	static struct spi_driver ad7303_driver = {
	.driver = {
	.name = "ad7303",
	.of_match_table = of_match_ptr(ad7303_spi_of_match),
	},
	.probe = ad7303_probe,
	.remove = ad7303_remove,
	.id_table = ad7303_spi_ids,
	};
	module_spi_driver(ad7303_driver);

	MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
	MODULE_DESCRIPTION("Analog Devices AD7303 DAC driver");
	MODULE_LICENSE("GPL v2");