drivers/iio/dac/ad5791.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * AD5760, AD5780, AD5781, AD5790, AD5791 Voltage Output Digital to Analog
  * Converter
  *
  * Copyright 2011 Analog Devices Inc.
  */

 #include <linux/interrupt.h>
 #include <linux/fs.h>
 #include <linux/device.h>
 #include <linux/delay.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/module.h>
 #include <linux/bitops.h>

 #include <linux/iio/iio.h>
 #include <linux/iio/sysfs.h>
 #include <linux/iio/dac/ad5791.h>

 #define AD5791_DAC_MASK			GENMASK(19, 0)

 #define AD5791_CMD_READ			BIT(23)
 #define AD5791_CMD_WRITE		0
 #define AD5791_ADDR(addr)		((addr) << 20)

 /* Registers */
 #define AD5791_ADDR_NOOP		0
 #define AD5791_ADDR_DAC0		1
 #define AD5791_ADDR_CTRL		2
 #define AD5791_ADDR_CLRCODE		3
 #define AD5791_ADDR_SW_CTRL		4

 /* Control Register */
 #define AD5791_CTRL_RBUF		BIT(1)
 #define AD5791_CTRL_OPGND		BIT(2)
 #define AD5791_CTRL_DACTRI		BIT(3)
 #define AD5791_CTRL_BIN2SC		BIT(4)
 #define AD5791_CTRL_SDODIS		BIT(5)
 #define AD5761_CTRL_LINCOMP(x)		((x) << 6)

 #define AD5791_LINCOMP_0_10		0
 #define AD5791_LINCOMP_10_12		1
 #define AD5791_LINCOMP_12_16		2
 #define AD5791_LINCOMP_16_19		3
 #define AD5791_LINCOMP_19_20		12

 #define AD5780_LINCOMP_0_10		0
 #define AD5780_LINCOMP_10_20		12

 /* Software Control Register */
 #define AD5791_SWCTRL_LDAC		BIT(0)
 #define AD5791_SWCTRL_CLR		BIT(1)
 #define AD5791_SWCTRL_RESET		BIT(2)

 #define AD5791_DAC_PWRDN_6K		0
 #define AD5791_DAC_PWRDN_3STATE		1

 /**
  * struct ad5791_chip_info - chip specific information
  * @name:		name of the dac chip
  * @channel:		channel specification
  * @get_lin_comp:	function pointer to the device specific function
  */
 struct ad5791_chip_info {
 	const char *name;
 	const struct iio_chan_spec channel;
 	int (*get_lin_comp)(unsigned int span);
 };

 /**
  * struct ad5791_state - driver instance specific data
  * @spi:			spi_device
  * @reg_vdd:		positive supply regulator
  * @reg_vss:		negative supply regulator
  * @gpio_reset:		reset gpio
  * @gpio_clear:		clear gpio
  * @gpio_ldac:		load dac gpio
  * @chip_info:		chip model specific constants
  * @vref_mv:		actual reference voltage used
  * @vref_neg_mv:	voltage of the negative supply
  * @ctrl:		control register cache
  * @pwr_down_mode:	current power down mode
  * @pwr_down:		true if device is powered down
  * @data:		spi transfer buffers
  */
 struct ad5791_state {
 	struct spi_device		*spi;
 	struct regulator		*reg_vdd;
 	struct regulator		*reg_vss;
 	struct gpio_desc		*gpio_reset;
 	struct gpio_desc		*gpio_clear;
 	struct gpio_desc		*gpio_ldac;
 	const struct ad5791_chip_info	*chip_info;
 	unsigned short			vref_mv;
 	unsigned int			vref_neg_mv;
 	unsigned			ctrl;
 	unsigned			pwr_down_mode;
 	bool				pwr_down;

 	union {
 		__be32 d32;
 		u8 d8[4];
 	} data[3] __aligned(IIO_DMA_MINALIGN);
 };

 static int ad5791_spi_write(struct ad5791_state *st, u8 addr, u32 val)
 {
 	st->data[0].d32 = cpu_to_be32(AD5791_CMD_WRITE |
 			      AD5791_ADDR(addr) |
 			      (val & AD5791_DAC_MASK));

 	return spi_write(st->spi, &st->data[0].d8[1], 3);
 }

 static int ad5791_spi_read(struct ad5791_state *st, u8 addr, u32 *val)
 {
 	int ret;
 	struct spi_transfer xfers[] = {
 		{
 			.tx_buf = &st->data[0].d8[1],
 			.bits_per_word = 8,
 			.len = 3,
 			.cs_change = 1,
 		}, {
 			.tx_buf = &st->data[1].d8[1],
 			.rx_buf = &st->data[2].d8[1],
 			.bits_per_word = 8,
 			.len = 3,
 		},
 	};

 	st->data[0].d32 = cpu_to_be32(AD5791_CMD_READ |
 			      AD5791_ADDR(addr));
 	st->data[1].d32 = cpu_to_be32(AD5791_ADDR(AD5791_ADDR_NOOP));

 	ret = spi_sync_transfer(st->spi, xfers, ARRAY_SIZE(xfers));

 	*val = be32_to_cpu(st->data[2].d32);

 	return ret;
 }

 static const char * const ad5791_powerdown_modes[] = {
 	"6kohm_to_gnd",
 	"three_state",
 };

 static int ad5791_get_powerdown_mode(struct iio_dev *indio_dev,
 	const struct iio_chan_spec *chan)
 {
 	struct ad5791_state *st = iio_priv(indio_dev);

 	return st->pwr_down_mode;
 }

 static int ad5791_set_powerdown_mode(struct iio_dev *indio_dev,
 	const struct iio_chan_spec *chan, unsigned int mode)
 {
 	struct ad5791_state *st = iio_priv(indio_dev);

 	st->pwr_down_mode = mode;

 	return 0;
 }

 static const struct iio_enum ad5791_powerdown_mode_enum = {
 	.items = ad5791_powerdown_modes,
 	.num_items = ARRAY_SIZE(ad5791_powerdown_modes),
 	.get = ad5791_get_powerdown_mode,
 	.set = ad5791_set_powerdown_mode,
 };

 static ssize_t ad5791_read_dac_powerdown(struct iio_dev *indio_dev,
 	uintptr_t private, const struct iio_chan_spec *chan, char *buf)
 {
 	struct ad5791_state *st = iio_priv(indio_dev);

 	return sysfs_emit(buf, "%d\n", st->pwr_down);
 }

 static ssize_t ad5791_write_dac_powerdown(struct iio_dev *indio_dev,
 	 uintptr_t private, const struct iio_chan_spec *chan, const char *buf,
 	 size_t len)
 {
 	bool pwr_down;
 	int ret;
 	struct ad5791_state *st = iio_priv(indio_dev);

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

 	if (!pwr_down) {
 		st->ctrl &= ~(AD5791_CTRL_OPGND | AD5791_CTRL_DACTRI);
 	} else {
 		if (st->pwr_down_mode == AD5791_DAC_PWRDN_6K)
 			st->ctrl |= AD5791_CTRL_OPGND;
 		else if (st->pwr_down_mode == AD5791_DAC_PWRDN_3STATE)
 			st->ctrl |= AD5791_CTRL_DACTRI;
 	}
 	st->pwr_down = pwr_down;

 	ret = ad5791_spi_write(st, AD5791_ADDR_CTRL, st->ctrl);

 	return ret ? ret : len;
 }

 static int ad5791_get_lin_comp(unsigned int span)
 {
 	if (span <= 10000)
 		return AD5791_LINCOMP_0_10;
 	else if (span <= 12000)
 		return AD5791_LINCOMP_10_12;
 	else if (span <= 16000)
 		return AD5791_LINCOMP_12_16;
 	else if (span <= 19000)
 		return AD5791_LINCOMP_16_19;
 	else
 		return AD5791_LINCOMP_19_20;
 }

 static int ad5780_get_lin_comp(unsigned int span)
 {
 	if (span <= 10000)
 		return AD5780_LINCOMP_0_10;
 	else
 		return AD5780_LINCOMP_10_20;
 }

 static int ad5791_read_raw(struct iio_dev *indio_dev,
 			   struct iio_chan_spec const *chan,
 			   int *val,
 			   int *val2,
 			   long m)
 {
 	struct ad5791_state *st = iio_priv(indio_dev);
 	u64 val64;
 	int ret;

 	switch (m) {
 	case IIO_CHAN_INFO_RAW:
 		ret = ad5791_spi_read(st, chan->address, val);
 		if (ret)
 			return ret;
 		*val &= AD5791_DAC_MASK;
 		*val >>= chan->scan_type.shift;
 		return IIO_VAL_INT;
 	case IIO_CHAN_INFO_SCALE:
 		*val = st->vref_mv;
 		*val2 = (1 << chan->scan_type.realbits) - 1;
 		return IIO_VAL_FRACTIONAL;
 	case IIO_CHAN_INFO_OFFSET:
 		val64 = (((u64)st->vref_neg_mv) << chan->scan_type.realbits);
 		do_div(val64, st->vref_mv);
 		*val = -val64;
 		return IIO_VAL_INT;
 	default:
 		return -EINVAL;
 	}

 };

 static const struct iio_chan_spec_ext_info ad5791_ext_info[] = {
 	{
 		.name = "powerdown",
 		.shared = IIO_SHARED_BY_TYPE,
 		.read = ad5791_read_dac_powerdown,
 		.write = ad5791_write_dac_powerdown,
 	},
 	IIO_ENUM("powerdown_mode", IIO_SHARED_BY_TYPE,
 		 &ad5791_powerdown_mode_enum),
 	IIO_ENUM_AVAILABLE("powerdown_mode", IIO_SHARED_BY_TYPE, &ad5791_powerdown_mode_enum),
 	{ },
 };

 #define AD5791_DEFINE_CHIP_INFO(_name, bits, _shift, _lin_comp)		\
 static const struct ad5791_chip_info _name##_chip_info = {		\
 	.name = #_name,							\
 	.get_lin_comp = &(_lin_comp),					\
 	.channel = {							\
 			.type = IIO_VOLTAGE,				\
 			.output = 1,					\
 			.indexed = 1,					\
 			.address = AD5791_ADDR_DAC0,			\
 			.channel = 0,					\
 			.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),	\
 			.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) |	\
 				BIT(IIO_CHAN_INFO_OFFSET),		\
 			.scan_type = {					\
 				.sign = 'u',				\
 				.realbits = (bits),			\
 				.storagebits = 24,			\
 				.shift = (_shift),			\
 			},						\
 			.ext_info = ad5791_ext_info,			\
 	},								\
 }

 AD5791_DEFINE_CHIP_INFO(ad5760, 16, 4, ad5780_get_lin_comp);
 AD5791_DEFINE_CHIP_INFO(ad5780, 18, 2, ad5780_get_lin_comp);
 AD5791_DEFINE_CHIP_INFO(ad5781, 18, 2, ad5791_get_lin_comp);
 AD5791_DEFINE_CHIP_INFO(ad5790, 20, 0, ad5791_get_lin_comp);
 AD5791_DEFINE_CHIP_INFO(ad5791, 20, 0, ad5791_get_lin_comp);

 static int ad5791_write_raw(struct iio_dev *indio_dev,
 			    struct iio_chan_spec const *chan,
 			    int val,
 			    int val2,
 			    long mask)
 {
 	struct ad5791_state *st = iio_priv(indio_dev);

 	switch (mask) {
 	case IIO_CHAN_INFO_RAW:
 		val &= GENMASK(chan->scan_type.realbits - 1, 0);
 		val <<= chan->scan_type.shift;

 		return ad5791_spi_write(st, chan->address, val);

 	default:
 		return -EINVAL;
 	}
 }

 static const struct iio_info ad5791_info = {
 	.read_raw = &ad5791_read_raw,
 	.write_raw = &ad5791_write_raw,
 };

 static int ad5791_probe(struct spi_device *spi)
 {
 	const struct ad5791_platform_data *pdata = dev_get_platdata(&spi->dev);
 	struct iio_dev *indio_dev;
 	struct ad5791_state *st;
 	int ret, pos_voltage_uv = 0, neg_voltage_uv = 0;
 	bool use_rbuf_gain2;

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

 	st->gpio_reset = devm_gpiod_get_optional(&spi->dev, "reset",
 						 GPIOD_OUT_HIGH);
 	if (IS_ERR(st->gpio_reset))
 		return PTR_ERR(st->gpio_reset);

 	st->gpio_clear = devm_gpiod_get_optional(&spi->dev, "clear",
 						 GPIOD_OUT_LOW);
 	if (IS_ERR(st->gpio_clear))
 		return PTR_ERR(st->gpio_clear);

 	st->gpio_ldac = devm_gpiod_get_optional(&spi->dev, "ldac",
 						GPIOD_OUT_HIGH);
 	if (IS_ERR(st->gpio_ldac))
 		return PTR_ERR(st->gpio_ldac);

 	st->pwr_down = true;
 	st->spi = spi;

 	if (pdata)
 		use_rbuf_gain2 = pdata->use_rbuf_gain2;
 	else
 		use_rbuf_gain2 = device_property_read_bool(&spi->dev,
 							   "adi,rbuf-gain2-en");

 	pos_voltage_uv = devm_regulator_get_enable_read_voltage(&spi->dev, "vdd");
 	if (pos_voltage_uv < 0 && pos_voltage_uv != -ENODEV)
 		return dev_err_probe(&spi->dev, pos_voltage_uv,
 				     "failed to get vdd voltage\n");

 	neg_voltage_uv = devm_regulator_get_enable_read_voltage(&spi->dev, "vss");
 	if (neg_voltage_uv < 0 && neg_voltage_uv != -ENODEV)
 		return dev_err_probe(&spi->dev, neg_voltage_uv,
 				     "failed to get vss voltage\n");

 	if (neg_voltage_uv >= 0 && pos_voltage_uv >= 0) {
 		st->vref_mv = (pos_voltage_uv + neg_voltage_uv) / 1000;
 		st->vref_neg_mv = neg_voltage_uv / 1000;
 	} else if (pdata) {
 		st->vref_mv = pdata->vref_pos_mv + pdata->vref_neg_mv;
 		st->vref_neg_mv = pdata->vref_neg_mv;
 	} else {
 		dev_warn(&spi->dev, "reference voltage unspecified\n");
 	}

 	if (st->gpio_reset) {
 		fsleep(20);
 		gpiod_set_value_cansleep(st->gpio_reset, 0);
 	} else {
 		ret = ad5791_spi_write(st, AD5791_ADDR_SW_CTRL, AD5791_SWCTRL_RESET);
 		if (ret)
 			return dev_err_probe(&spi->dev, ret, "fail to reset\n");
 	}

 	st->chip_info = spi_get_device_match_data(spi);
 	if (!st->chip_info)
 		return dev_err_probe(&spi->dev, -EINVAL, "no chip info\n");

 	st->ctrl = AD5761_CTRL_LINCOMP(st->chip_info->get_lin_comp(st->vref_mv))
 		  | (use_rbuf_gain2 ? 0 : AD5791_CTRL_RBUF) |
 		  AD5791_CTRL_BIN2SC;

 	ret = ad5791_spi_write(st, AD5791_ADDR_CTRL, st->ctrl |
 		AD5791_CTRL_OPGND | AD5791_CTRL_DACTRI);
 	if (ret)
 		return dev_err_probe(&spi->dev, ret, "fail to write ctrl register\n");

 	indio_dev->info = &ad5791_info;
 	indio_dev->modes = INDIO_DIRECT_MODE;
 	indio_dev->channels = &st->chip_info->channel;
 	indio_dev->num_channels = 1;
 	indio_dev->name = st->chip_info->name;
 	return devm_iio_device_register(&spi->dev, indio_dev);
 }

 static const struct of_device_id ad5791_of_match[] = {
 	{ .compatible = "adi,ad5760", .data = &ad5760_chip_info },
 	{ .compatible = "adi,ad5780", .data = &ad5780_chip_info },
 	{ .compatible = "adi,ad5781", .data = &ad5781_chip_info },
 	{ .compatible = "adi,ad5790", .data = &ad5790_chip_info },
 	{ .compatible = "adi,ad5791", .data = &ad5791_chip_info },
 	{ }
 };
 MODULE_DEVICE_TABLE(of, ad5791_of_match);

 static const struct spi_device_id ad5791_id[] = {
 	{ "ad5760", (kernel_ulong_t)&ad5760_chip_info },
 	{ "ad5780", (kernel_ulong_t)&ad5780_chip_info },
 	{ "ad5781", (kernel_ulong_t)&ad5781_chip_info },
 	{ "ad5790", (kernel_ulong_t)&ad5790_chip_info },
 	{ "ad5791", (kernel_ulong_t)&ad5791_chip_info },
 	{ }
 };
 MODULE_DEVICE_TABLE(spi, ad5791_id);

 static struct spi_driver ad5791_driver = {
 	.driver = {
 		   .name = "ad5791",
 		   .of_match_table = ad5791_of_match,
 		   },
 	.probe = ad5791_probe,
 	.id_table = ad5791_id,
 };
 module_spi_driver(ad5791_driver);

 MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
 MODULE_DESCRIPTION("Analog Devices AD5760/AD5780/AD5781/AD5790/AD5791 DAC");
 MODULE_LICENSE("GPL v2");
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* AD5760, AD5780, AD5781, AD5790, AD5791 Voltage Output Digital to Analog
	* Converter
	*
	* Copyright 2011 Analog Devices Inc.
	*/

	#include <linux/interrupt.h>
	#include <linux/fs.h>
	#include <linux/device.h>
	#include <linux/delay.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/module.h>
	#include <linux/bitops.h>

	#include <linux/iio/iio.h>
	#include <linux/iio/sysfs.h>
	#include <linux/iio/dac/ad5791.h>

	#define AD5791_DAC_MASK GENMASK(19, 0)

	#define AD5791_CMD_READ BIT(23)
	#define AD5791_CMD_WRITE 0
	#define AD5791_ADDR(addr) ((addr) << 20)

	/* Registers */
	#define AD5791_ADDR_NOOP 0
	#define AD5791_ADDR_DAC0 1
	#define AD5791_ADDR_CTRL 2
	#define AD5791_ADDR_CLRCODE 3
	#define AD5791_ADDR_SW_CTRL 4

	/* Control Register */
	#define AD5791_CTRL_RBUF BIT(1)
	#define AD5791_CTRL_OPGND BIT(2)
	#define AD5791_CTRL_DACTRI BIT(3)
	#define AD5791_CTRL_BIN2SC BIT(4)
	#define AD5791_CTRL_SDODIS BIT(5)
	#define AD5761_CTRL_LINCOMP(x) ((x) << 6)

	#define AD5791_LINCOMP_0_10 0
	#define AD5791_LINCOMP_10_12 1
	#define AD5791_LINCOMP_12_16 2
	#define AD5791_LINCOMP_16_19 3
	#define AD5791_LINCOMP_19_20 12

	#define AD5780_LINCOMP_0_10 0
	#define AD5780_LINCOMP_10_20 12

	/* Software Control Register */
	#define AD5791_SWCTRL_LDAC BIT(0)
	#define AD5791_SWCTRL_CLR BIT(1)
	#define AD5791_SWCTRL_RESET BIT(2)

	#define AD5791_DAC_PWRDN_6K 0
	#define AD5791_DAC_PWRDN_3STATE 1

	/**
	* struct ad5791_chip_info - chip specific information
	* @name: name of the dac chip
	* @channel: channel specification
	* @get_lin_comp: function pointer to the device specific function
	*/
	struct ad5791_chip_info {
	const char *name;
	const struct iio_chan_spec channel;
	int (*get_lin_comp)(unsigned int span);
	};

	/**
	* struct ad5791_state - driver instance specific data
	* @spi: spi_device
	* @reg_vdd: positive supply regulator
	* @reg_vss: negative supply regulator
	* @gpio_reset: reset gpio
	* @gpio_clear: clear gpio
	* @gpio_ldac: load dac gpio
	* @chip_info: chip model specific constants
	* @vref_mv: actual reference voltage used
	* @vref_neg_mv: voltage of the negative supply
	* @ctrl: control register cache
	* @pwr_down_mode: current power down mode
	* @pwr_down: true if device is powered down
	* @data: spi transfer buffers
	*/
	struct ad5791_state {
	struct spi_device *spi;
	struct regulator *reg_vdd;
	struct regulator *reg_vss;
	struct gpio_desc *gpio_reset;
	struct gpio_desc *gpio_clear;
	struct gpio_desc *gpio_ldac;
	const struct ad5791_chip_info *chip_info;
	unsigned short vref_mv;
	unsigned int vref_neg_mv;
	unsigned ctrl;
	unsigned pwr_down_mode;
	bool pwr_down;

	union {
	__be32 d32;
	u8 d8[4];
	} data[3] __aligned(IIO_DMA_MINALIGN);
	};

	static int ad5791_spi_write(struct ad5791_state *st, u8 addr, u32 val)
	{
	st->data[0].d32 = cpu_to_be32(AD5791_CMD_WRITE \|
	AD5791_ADDR(addr) \|
	(val & AD5791_DAC_MASK));

	return spi_write(st->spi, &st->data[0].d8[1], 3);
	}

	static int ad5791_spi_read(struct ad5791_state st, u8 addr, u32 val)
	{
	int ret;
	struct spi_transfer xfers[] = {
	{
	.tx_buf = &st->data[0].d8[1],
	.bits_per_word = 8,
	.len = 3,
	.cs_change = 1,
	}, {
	.tx_buf = &st->data[1].d8[1],
	.rx_buf = &st->data[2].d8[1],
	.bits_per_word = 8,
	.len = 3,
	},
	};

	st->data[0].d32 = cpu_to_be32(AD5791_CMD_READ \|
	AD5791_ADDR(addr));
	st->data[1].d32 = cpu_to_be32(AD5791_ADDR(AD5791_ADDR_NOOP));

	ret = spi_sync_transfer(st->spi, xfers, ARRAY_SIZE(xfers));

	*val = be32_to_cpu(st->data[2].d32);

	return ret;
	}

	static const char * const ad5791_powerdown_modes[] = {
	"6kohm_to_gnd",
	"three_state",
	};

	static int ad5791_get_powerdown_mode(struct iio_dev *indio_dev,
	const struct iio_chan_spec *chan)
	{
	struct ad5791_state *st = iio_priv(indio_dev);

	return st->pwr_down_mode;
	}

	static int ad5791_set_powerdown_mode(struct iio_dev *indio_dev,
	const struct iio_chan_spec *chan, unsigned int mode)
	{
	struct ad5791_state *st = iio_priv(indio_dev);

	st->pwr_down_mode = mode;

	return 0;
	}

	static const struct iio_enum ad5791_powerdown_mode_enum = {
	.items = ad5791_powerdown_modes,
	.num_items = ARRAY_SIZE(ad5791_powerdown_modes),
	.get = ad5791_get_powerdown_mode,
	.set = ad5791_set_powerdown_mode,
	};

	static ssize_t ad5791_read_dac_powerdown(struct iio_dev *indio_dev,
	uintptr_t private, const struct iio_chan_spec chan, char buf)
	{
	struct ad5791_state *st = iio_priv(indio_dev);

	return sysfs_emit(buf, "%d\n", st->pwr_down);
	}

	static ssize_t ad5791_write_dac_powerdown(struct iio_dev *indio_dev,
	uintptr_t private, const struct iio_chan_spec chan, const char buf,
	size_t len)
	{
	bool pwr_down;
	int ret;
	struct ad5791_state *st = iio_priv(indio_dev);

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

	if (!pwr_down) {
	st->ctrl &= ~(AD5791_CTRL_OPGND \| AD5791_CTRL_DACTRI);
	} else {
	if (st->pwr_down_mode == AD5791_DAC_PWRDN_6K)
	st->ctrl \|= AD5791_CTRL_OPGND;
	else if (st->pwr_down_mode == AD5791_DAC_PWRDN_3STATE)
	st->ctrl \|= AD5791_CTRL_DACTRI;
	}
	st->pwr_down = pwr_down;

	ret = ad5791_spi_write(st, AD5791_ADDR_CTRL, st->ctrl);

	return ret ? ret : len;
	}

	static int ad5791_get_lin_comp(unsigned int span)
	{
	if (span <= 10000)
	return AD5791_LINCOMP_0_10;
	else if (span <= 12000)
	return AD5791_LINCOMP_10_12;
	else if (span <= 16000)
	return AD5791_LINCOMP_12_16;
	else if (span <= 19000)
	return AD5791_LINCOMP_16_19;
	else
	return AD5791_LINCOMP_19_20;
	}

	static int ad5780_get_lin_comp(unsigned int span)
	{
	if (span <= 10000)
	return AD5780_LINCOMP_0_10;
	else
	return AD5780_LINCOMP_10_20;
	}

	static int ad5791_read_raw(struct iio_dev *indio_dev,
	struct iio_chan_spec const *chan,
	int *val,
	int *val2,
	long m)
	{
	struct ad5791_state *st = iio_priv(indio_dev);
	u64 val64;
	int ret;

	switch (m) {
	case IIO_CHAN_INFO_RAW:
	ret = ad5791_spi_read(st, chan->address, val);
	if (ret)
	return ret;
	*val &= AD5791_DAC_MASK;
	*val >>= chan->scan_type.shift;
	return IIO_VAL_INT;
	case IIO_CHAN_INFO_SCALE:
	*val = st->vref_mv;
	*val2 = (1 << chan->scan_type.realbits) - 1;
	return IIO_VAL_FRACTIONAL;
	case IIO_CHAN_INFO_OFFSET:
	val64 = (((u64)st->vref_neg_mv) << chan->scan_type.realbits);
	do_div(val64, st->vref_mv);
	*val = -val64;
	return IIO_VAL_INT;
	default:
	return -EINVAL;
	}

	};

	static const struct iio_chan_spec_ext_info ad5791_ext_info[] = {
	{
	.name = "powerdown",
	.shared = IIO_SHARED_BY_TYPE,
	.read = ad5791_read_dac_powerdown,
	.write = ad5791_write_dac_powerdown,
	},
	IIO_ENUM("powerdown_mode", IIO_SHARED_BY_TYPE,
	&ad5791_powerdown_mode_enum),
	IIO_ENUM_AVAILABLE("powerdown_mode", IIO_SHARED_BY_TYPE, &ad5791_powerdown_mode_enum),
	{ },
	};

	#define AD5791_DEFINE_CHIP_INFO(_name, bits, _shift, _lin_comp) \
	static const struct ad5791_chip_info _name##_chip_info = { \
	.name = #_name, \
	.get_lin_comp = &(_lin_comp), \
	.channel = { \
	.type = IIO_VOLTAGE, \
	.output = 1, \
	.indexed = 1, \
	.address = AD5791_ADDR_DAC0, \
	.channel = 0, \
	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \| \
	BIT(IIO_CHAN_INFO_OFFSET), \
	.scan_type = { \
	.sign = 'u', \
	.realbits = (bits), \
	.storagebits = 24, \
	.shift = (_shift), \
	}, \
	.ext_info = ad5791_ext_info, \
	}, \
	}

	AD5791_DEFINE_CHIP_INFO(ad5760, 16, 4, ad5780_get_lin_comp);
	AD5791_DEFINE_CHIP_INFO(ad5780, 18, 2, ad5780_get_lin_comp);
	AD5791_DEFINE_CHIP_INFO(ad5781, 18, 2, ad5791_get_lin_comp);
	AD5791_DEFINE_CHIP_INFO(ad5790, 20, 0, ad5791_get_lin_comp);
	AD5791_DEFINE_CHIP_INFO(ad5791, 20, 0, ad5791_get_lin_comp);

	static int ad5791_write_raw(struct iio_dev *indio_dev,
	struct iio_chan_spec const *chan,
	int val,
	int val2,
	long mask)
	{
	struct ad5791_state *st = iio_priv(indio_dev);

	switch (mask) {
	case IIO_CHAN_INFO_RAW:
	val &= GENMASK(chan->scan_type.realbits - 1, 0);
	val <<= chan->scan_type.shift;

	return ad5791_spi_write(st, chan->address, val);

	default:
	return -EINVAL;
	}
	}

	static const struct iio_info ad5791_info = {
	.read_raw = &ad5791_read_raw,
	.write_raw = &ad5791_write_raw,
	};

	static int ad5791_probe(struct spi_device *spi)
	{
	const struct ad5791_platform_data *pdata = dev_get_platdata(&spi->dev);
	struct iio_dev *indio_dev;
	struct ad5791_state *st;
	int ret, pos_voltage_uv = 0, neg_voltage_uv = 0;
	bool use_rbuf_gain2;

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

	st->gpio_reset = devm_gpiod_get_optional(&spi->dev, "reset",
	GPIOD_OUT_HIGH);
	if (IS_ERR(st->gpio_reset))
	return PTR_ERR(st->gpio_reset);

	st->gpio_clear = devm_gpiod_get_optional(&spi->dev, "clear",
	GPIOD_OUT_LOW);
	if (IS_ERR(st->gpio_clear))
	return PTR_ERR(st->gpio_clear);

	st->gpio_ldac = devm_gpiod_get_optional(&spi->dev, "ldac",
	GPIOD_OUT_HIGH);
	if (IS_ERR(st->gpio_ldac))
	return PTR_ERR(st->gpio_ldac);

	st->pwr_down = true;
	st->spi = spi;

	if (pdata)
	use_rbuf_gain2 = pdata->use_rbuf_gain2;
	else
	use_rbuf_gain2 = device_property_read_bool(&spi->dev,
	"adi,rbuf-gain2-en");

	pos_voltage_uv = devm_regulator_get_enable_read_voltage(&spi->dev, "vdd");
	if (pos_voltage_uv < 0 && pos_voltage_uv != -ENODEV)
	return dev_err_probe(&spi->dev, pos_voltage_uv,
	"failed to get vdd voltage\n");

	neg_voltage_uv = devm_regulator_get_enable_read_voltage(&spi->dev, "vss");
	if (neg_voltage_uv < 0 && neg_voltage_uv != -ENODEV)
	return dev_err_probe(&spi->dev, neg_voltage_uv,
	"failed to get vss voltage\n");

	if (neg_voltage_uv >= 0 && pos_voltage_uv >= 0) {
	st->vref_mv = (pos_voltage_uv + neg_voltage_uv) / 1000;
	st->vref_neg_mv = neg_voltage_uv / 1000;
	} else if (pdata) {
	st->vref_mv = pdata->vref_pos_mv + pdata->vref_neg_mv;
	st->vref_neg_mv = pdata->vref_neg_mv;
	} else {
	dev_warn(&spi->dev, "reference voltage unspecified\n");
	}

	if (st->gpio_reset) {
	fsleep(20);
	gpiod_set_value_cansleep(st->gpio_reset, 0);
	} else {
	ret = ad5791_spi_write(st, AD5791_ADDR_SW_CTRL, AD5791_SWCTRL_RESET);
	if (ret)
	return dev_err_probe(&spi->dev, ret, "fail to reset\n");
	}

	st->chip_info = spi_get_device_match_data(spi);
	if (!st->chip_info)
	return dev_err_probe(&spi->dev, -EINVAL, "no chip info\n");

	st->ctrl = AD5761_CTRL_LINCOMP(st->chip_info->get_lin_comp(st->vref_mv))
	\| (use_rbuf_gain2 ? 0 : AD5791_CTRL_RBUF) \|
	AD5791_CTRL_BIN2SC;

	ret = ad5791_spi_write(st, AD5791_ADDR_CTRL, st->ctrl \|
	AD5791_CTRL_OPGND \| AD5791_CTRL_DACTRI);
	if (ret)
	return dev_err_probe(&spi->dev, ret, "fail to write ctrl register\n");

	indio_dev->info = &ad5791_info;
	indio_dev->modes = INDIO_DIRECT_MODE;
	indio_dev->channels = &st->chip_info->channel;
	indio_dev->num_channels = 1;
	indio_dev->name = st->chip_info->name;
	return devm_iio_device_register(&spi->dev, indio_dev);
	}

	static const struct of_device_id ad5791_of_match[] = {
	{ .compatible = "adi,ad5760", .data = &ad5760_chip_info },
	{ .compatible = "adi,ad5780", .data = &ad5780_chip_info },
	{ .compatible = "adi,ad5781", .data = &ad5781_chip_info },
	{ .compatible = "adi,ad5790", .data = &ad5790_chip_info },
	{ .compatible = "adi,ad5791", .data = &ad5791_chip_info },
	{ }
	};
	MODULE_DEVICE_TABLE(of, ad5791_of_match);

	static const struct spi_device_id ad5791_id[] = {
	{ "ad5760", (kernel_ulong_t)&ad5760_chip_info },
	{ "ad5780", (kernel_ulong_t)&ad5780_chip_info },
	{ "ad5781", (kernel_ulong_t)&ad5781_chip_info },
	{ "ad5790", (kernel_ulong_t)&ad5790_chip_info },
	{ "ad5791", (kernel_ulong_t)&ad5791_chip_info },
	{ }
	};
	MODULE_DEVICE_TABLE(spi, ad5791_id);

	static struct spi_driver ad5791_driver = {
	.driver = {
	.name = "ad5791",
	.of_match_table = ad5791_of_match,
	},
	.probe = ad5791_probe,
	.id_table = ad5791_id,
	};
	module_spi_driver(ad5791_driver);

	MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
	MODULE_DESCRIPTION("Analog Devices AD5760/AD5780/AD5781/AD5790/AD5791 DAC");
	MODULE_LICENSE("GPL v2");