drivers/iio/dac/ad5686.c - arm/linux - Git at Google

 /*
  * AD5686R, AD5685R, AD5684R Digital to analog converters  driver
  *
  * Copyright 2011 Analog Devices Inc.
  *
  * Licensed under the GPL-2.
  */

 #include <linux/interrupt.h>
 #include <linux/fs.h>
 #include <linux/device.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/iio/iio.h>
 #include <linux/iio/sysfs.h>

 #define AD5686_DAC_CHANNELS			4

 #define AD5686_ADDR(x)				((x) << 16)
 #define AD5686_CMD(x)				((x) << 20)

 #define AD5686_ADDR_DAC(chan)		(0x1 << (chan))
 #define AD5686_ADDR_ALL_DAC			0xF

 #define AD5686_CMD_NOOP				0x0
 #define AD5686_CMD_WRITE_INPUT_N		0x1
 #define AD5686_CMD_UPDATE_DAC_N			0x2
 #define AD5686_CMD_WRITE_INPUT_N_UPDATE_N	0x3
 #define AD5686_CMD_POWERDOWN_DAC		0x4
 #define AD5686_CMD_LDAC_MASK			0x5
 #define AD5686_CMD_RESET			0x6
 #define AD5686_CMD_INTERNAL_REFER_SETUP		0x7
 #define AD5686_CMD_DAISY_CHAIN_ENABLE		0x8
 #define AD5686_CMD_READBACK_ENABLE		0x9

 #define AD5686_LDAC_PWRDN_NONE			0x0
 #define AD5686_LDAC_PWRDN_1K			0x1
 #define AD5686_LDAC_PWRDN_100K			0x2
 #define AD5686_LDAC_PWRDN_3STATE		0x3

 /**
  * struct ad5686_chip_info - chip specific information
  * @int_vref_mv:	AD5620/40/60: the internal reference voltage
  * @channel:		channel specification
 */

 struct ad5686_chip_info {
 	u16				int_vref_mv;
 	struct iio_chan_spec		channel[AD5686_DAC_CHANNELS];
 };

 /**
  * struct ad5446_state - driver instance specific data
  * @spi:		spi_device
  * @chip_info:		chip model specific constants, available modes etc
  * @reg:		supply regulator
  * @vref_mv:		actual reference voltage used
  * @pwr_down_mask:	power down mask
  * @pwr_down_mode:	current power down mode
  * @data:		spi transfer buffers
  */

 struct ad5686_state {
 	struct spi_device		*spi;
 	const struct ad5686_chip_info	*chip_info;
 	struct regulator		*reg;
 	unsigned short			vref_mv;
 	unsigned			pwr_down_mask;
 	unsigned			pwr_down_mode;
 	/*
 	 * DMA (thus cache coherency maintenance) requires the
 	 * transfer buffers to live in their own cache lines.
 	 */

 	union {
 		__be32 d32;
 		u8 d8[4];
 	} data[3] ____cacheline_aligned;
 };

 /**
  * ad5686_supported_device_ids:
  */

 enum ad5686_supported_device_ids {
 	ID_AD5684,
 	ID_AD5685,
 	ID_AD5686,
 };
 static int ad5686_spi_write(struct ad5686_state *st,
 			     u8 cmd, u8 addr, u16 val, u8 shift)
 {
 	val <<= shift;

 	st->data[0].d32 = cpu_to_be32(AD5686_CMD(cmd) |
 			      AD5686_ADDR(addr) |
 			      val);

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

 static int ad5686_spi_read(struct ad5686_state *st, u8 addr)
 {
 	struct spi_transfer t[] = {
 		{
 			.tx_buf = &st->data[0].d8[1],
 			.len = 3,
 			.cs_change = 1,
 		}, {
 			.tx_buf = &st->data[1].d8[1],
 			.rx_buf = &st->data[2].d8[1],
 			.len = 3,
 		},
 	};
 	int ret;

 	st->data[0].d32 = cpu_to_be32(AD5686_CMD(AD5686_CMD_READBACK_ENABLE) |
 			      AD5686_ADDR(addr));
 	st->data[1].d32 = cpu_to_be32(AD5686_CMD(AD5686_CMD_NOOP));

 	ret = spi_sync_transfer(st->spi, t, ARRAY_SIZE(t));
 	if (ret < 0)
 		return ret;

 	return be32_to_cpu(st->data[2].d32);
 }

 static const char * const ad5686_powerdown_modes[] = {
 	"1kohm_to_gnd",
 	"100kohm_to_gnd",
 	"three_state"
 };

 static int ad5686_get_powerdown_mode(struct iio_dev *indio_dev,
 	const struct iio_chan_spec *chan)
 {
 	struct ad5686_state *st = iio_priv(indio_dev);

 	return ((st->pwr_down_mode >> (chan->channel * 2)) & 0x3) - 1;
 }

 static int ad5686_set_powerdown_mode(struct iio_dev *indio_dev,
 	const struct iio_chan_spec *chan, unsigned int mode)
 {
 	struct ad5686_state *st = iio_priv(indio_dev);

 	st->pwr_down_mode &= ~(0x3 << (chan->channel * 2));
 	st->pwr_down_mode |= ((mode + 1) << (chan->channel * 2));

 	return 0;
 }

 static const struct iio_enum ad5686_powerdown_mode_enum = {
 	.items = ad5686_powerdown_modes,
 	.num_items = ARRAY_SIZE(ad5686_powerdown_modes),
 	.get = ad5686_get_powerdown_mode,
 	.set = ad5686_set_powerdown_mode,
 };

 static ssize_t ad5686_read_dac_powerdown(struct iio_dev *indio_dev,
 	uintptr_t private, const struct iio_chan_spec *chan, char *buf)
 {
 	struct ad5686_state *st = iio_priv(indio_dev);

 	return sprintf(buf, "%d\n", !!(st->pwr_down_mask &
 			(0x3 << (chan->channel * 2))));
 }

 static ssize_t ad5686_write_dac_powerdown(struct iio_dev *indio_dev,
 	 uintptr_t private, const struct iio_chan_spec *chan, const char *buf,
 	 size_t len)
 {
 	bool readin;
 	int ret;
 	struct ad5686_state *st = iio_priv(indio_dev);

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

 	if (readin)
 		st->pwr_down_mask |= (0x3 << (chan->channel * 2));
 	else
 		st->pwr_down_mask &= ~(0x3 << (chan->channel * 2));

 	ret = ad5686_spi_write(st, AD5686_CMD_POWERDOWN_DAC, 0,
 			       st->pwr_down_mask & st->pwr_down_mode, 0);

 	return ret ? ret : len;
 }

 static int ad5686_read_raw(struct iio_dev *indio_dev,
 			   struct iio_chan_spec const *chan,
 			   int *val,
 			   int *val2,
 			   long m)
 {
 	struct ad5686_state *st = iio_priv(indio_dev);
 	int ret;

 	switch (m) {
 	case IIO_CHAN_INFO_RAW:
 		mutex_lock(&indio_dev->mlock);
 		ret = ad5686_spi_read(st, chan->address);
 		mutex_unlock(&indio_dev->mlock);
 		if (ret < 0)
 			return ret;
 		*val = ret;
 		return IIO_VAL_INT;
 	case IIO_CHAN_INFO_SCALE:
 		*val = st->vref_mv;
 		*val2 = chan->scan_type.realbits;
 		return IIO_VAL_FRACTIONAL_LOG2;
 	}
 	return -EINVAL;
 }

 static int ad5686_write_raw(struct iio_dev *indio_dev,
 			       struct iio_chan_spec const *chan,
 			       int val,
 			       int val2,
 			       long mask)
 {
 	struct ad5686_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 = ad5686_spi_write(st,
 				 AD5686_CMD_WRITE_INPUT_N_UPDATE_N,
 				 chan->address,
 				 val,
 				 chan->scan_type.shift);
 		mutex_unlock(&indio_dev->mlock);
 		break;
 	default:
 		ret = -EINVAL;
 	}

 	return ret;
 }

 static const struct iio_info ad5686_info = {
 	.read_raw = ad5686_read_raw,
 	.write_raw = ad5686_write_raw,
 	.driver_module = THIS_MODULE,
 };

 static const struct iio_chan_spec_ext_info ad5686_ext_info[] = {
 	{
 		.name = "powerdown",
 		.read = ad5686_read_dac_powerdown,
 		.write = ad5686_write_dac_powerdown,
 		.shared = IIO_SEPARATE,
 	},
 	IIO_ENUM("powerdown_mode", IIO_SEPARATE, &ad5686_powerdown_mode_enum),
 	IIO_ENUM_AVAILABLE("powerdown_mode", &ad5686_powerdown_mode_enum),
 	{ },
 };

 #define AD5868_CHANNEL(chan, bits, _shift) {			\
 		.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 = AD5686_ADDR_DAC(chan),		\
 		.scan_type = {					\
 			.sign = 'u',				\
 			.realbits = (bits),			\
 			.storagebits = 16,			\
 			.shift = (_shift),			\
 		},						\
 		.ext_info = ad5686_ext_info,			\
 }

 static const struct ad5686_chip_info ad5686_chip_info_tbl[] = {
 	[ID_AD5684] = {
 		.channel[0] = AD5868_CHANNEL(0, 12, 4),
 		.channel[1] = AD5868_CHANNEL(1, 12, 4),
 		.channel[2] = AD5868_CHANNEL(2, 12, 4),
 		.channel[3] = AD5868_CHANNEL(3, 12, 4),
 		.int_vref_mv = 2500,
 	},
 	[ID_AD5685] = {
 		.channel[0] = AD5868_CHANNEL(0, 14, 2),
 		.channel[1] = AD5868_CHANNEL(1, 14, 2),
 		.channel[2] = AD5868_CHANNEL(2, 14, 2),
 		.channel[3] = AD5868_CHANNEL(3, 14, 2),
 		.int_vref_mv = 2500,
 	},
 	[ID_AD5686] = {
 		.channel[0] = AD5868_CHANNEL(0, 16, 0),
 		.channel[1] = AD5868_CHANNEL(1, 16, 0),
 		.channel[2] = AD5868_CHANNEL(2, 16, 0),
 		.channel[3] = AD5868_CHANNEL(3, 16, 0),
 		.int_vref_mv = 2500,
 	},
 };


 static int ad5686_probe(struct spi_device *spi)
 {
 	struct ad5686_state *st;
 	struct iio_dev *indio_dev;
 	int ret, voltage_uv = 0;

 	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->reg = devm_regulator_get_optional(&spi->dev, "vcc");
 	if (!IS_ERR(st->reg)) {
 		ret = regulator_enable(st->reg);
 		if (ret)
 			return ret;

 		ret = regulator_get_voltage(st->reg);
 		if (ret < 0)
 			goto error_disable_reg;

 		voltage_uv = ret;
 	}

 	st->chip_info =
 		&ad5686_chip_info_tbl[spi_get_device_id(spi)->driver_data];

 	if (voltage_uv)
 		st->vref_mv = voltage_uv / 1000;
 	else
 		st->vref_mv = st->chip_info->int_vref_mv;

 	st->spi = spi;

 	/* Set all the power down mode for all channels to 1K pulldown */
 	st->pwr_down_mode = 0x55;

 	indio_dev->dev.parent = &spi->dev;
 	indio_dev->name = spi_get_device_id(spi)->name;
 	indio_dev->info = &ad5686_info;
 	indio_dev->modes = INDIO_DIRECT_MODE;
 	indio_dev->channels = st->chip_info->channel;
 	indio_dev->num_channels = AD5686_DAC_CHANNELS;

 	ret = ad5686_spi_write(st, AD5686_CMD_INTERNAL_REFER_SETUP, 0,
 				!!voltage_uv, 0);
 	if (ret)
 		goto error_disable_reg;

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

 	return 0;

 error_disable_reg:
 	if (!IS_ERR(st->reg))
 		regulator_disable(st->reg);
 	return ret;
 }

 static int ad5686_remove(struct spi_device *spi)
 {
 	struct iio_dev *indio_dev = spi_get_drvdata(spi);
 	struct ad5686_state *st = iio_priv(indio_dev);

 	iio_device_unregister(indio_dev);
 	if (!IS_ERR(st->reg))
 		regulator_disable(st->reg);

 	return 0;
 }

 static const struct spi_device_id ad5686_id[] = {
 	{"ad5684", ID_AD5684},
 	{"ad5685", ID_AD5685},
 	{"ad5686", ID_AD5686},
 	{}
 };
 MODULE_DEVICE_TABLE(spi, ad5686_id);

 static struct spi_driver ad5686_driver = {
 	.driver = {
 		   .name = "ad5686",
 		   },
 	.probe = ad5686_probe,
 	.remove = ad5686_remove,
 	.id_table = ad5686_id,
 };
 module_spi_driver(ad5686_driver);

 MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
 MODULE_DESCRIPTION("Analog Devices AD5686/85/84 DAC");
 MODULE_LICENSE("GPL v2");
	/*
	* AD5686R, AD5685R, AD5684R Digital to analog converters driver
	*
	* Copyright 2011 Analog Devices Inc.
	*
	* Licensed under the GPL-2.
	*/

	#include <linux/interrupt.h>
	#include <linux/fs.h>
	#include <linux/device.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/iio/iio.h>
	#include <linux/iio/sysfs.h>

	#define AD5686_DAC_CHANNELS 4

	#define AD5686_ADDR(x) ((x) << 16)
	#define AD5686_CMD(x) ((x) << 20)

	#define AD5686_ADDR_DAC(chan) (0x1 << (chan))
	#define AD5686_ADDR_ALL_DAC 0xF

	#define AD5686_CMD_NOOP 0x0
	#define AD5686_CMD_WRITE_INPUT_N 0x1
	#define AD5686_CMD_UPDATE_DAC_N 0x2
	#define AD5686_CMD_WRITE_INPUT_N_UPDATE_N 0x3
	#define AD5686_CMD_POWERDOWN_DAC 0x4
	#define AD5686_CMD_LDAC_MASK 0x5
	#define AD5686_CMD_RESET 0x6
	#define AD5686_CMD_INTERNAL_REFER_SETUP 0x7
	#define AD5686_CMD_DAISY_CHAIN_ENABLE 0x8
	#define AD5686_CMD_READBACK_ENABLE 0x9

	#define AD5686_LDAC_PWRDN_NONE 0x0
	#define AD5686_LDAC_PWRDN_1K 0x1
	#define AD5686_LDAC_PWRDN_100K 0x2
	#define AD5686_LDAC_PWRDN_3STATE 0x3

	/**
	* struct ad5686_chip_info - chip specific information
	* @int_vref_mv: AD5620/40/60: the internal reference voltage
	* @channel: channel specification
	*/

	struct ad5686_chip_info {
	u16 int_vref_mv;
	struct iio_chan_spec channel[AD5686_DAC_CHANNELS];
	};

	/**
	* struct ad5446_state - driver instance specific data
	* @spi: spi_device
	* @chip_info: chip model specific constants, available modes etc
	* @reg: supply regulator
	* @vref_mv: actual reference voltage used
	* @pwr_down_mask: power down mask
	* @pwr_down_mode: current power down mode
	* @data: spi transfer buffers
	*/

	struct ad5686_state {
	struct spi_device *spi;
	const struct ad5686_chip_info *chip_info;
	struct regulator *reg;
	unsigned short vref_mv;
	unsigned pwr_down_mask;
	unsigned pwr_down_mode;
	/*
	* DMA (thus cache coherency maintenance) requires the
	* transfer buffers to live in their own cache lines.
	*/

	union {
	__be32 d32;
	u8 d8[4];
	} data[3] ____cacheline_aligned;
	};

	/**
	* ad5686_supported_device_ids:
	*/

	enum ad5686_supported_device_ids {
	ID_AD5684,
	ID_AD5685,
	ID_AD5686,
	};
	static int ad5686_spi_write(struct ad5686_state *st,
	u8 cmd, u8 addr, u16 val, u8 shift)
	{
	val <<= shift;

	st->data[0].d32 = cpu_to_be32(AD5686_CMD(cmd) \|
	AD5686_ADDR(addr) \|
	val);

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

	static int ad5686_spi_read(struct ad5686_state *st, u8 addr)
	{
	struct spi_transfer t[] = {
	{
	.tx_buf = &st->data[0].d8[1],
	.len = 3,
	.cs_change = 1,
	}, {
	.tx_buf = &st->data[1].d8[1],
	.rx_buf = &st->data[2].d8[1],
	.len = 3,
	},
	};
	int ret;

	st->data[0].d32 = cpu_to_be32(AD5686_CMD(AD5686_CMD_READBACK_ENABLE) \|
	AD5686_ADDR(addr));
	st->data[1].d32 = cpu_to_be32(AD5686_CMD(AD5686_CMD_NOOP));

	ret = spi_sync_transfer(st->spi, t, ARRAY_SIZE(t));
	if (ret < 0)
	return ret;

	return be32_to_cpu(st->data[2].d32);
	}

	static const char * const ad5686_powerdown_modes[] = {
	"1kohm_to_gnd",
	"100kohm_to_gnd",
	"three_state"
	};

	static int ad5686_get_powerdown_mode(struct iio_dev *indio_dev,
	const struct iio_chan_spec *chan)
	{
	struct ad5686_state *st = iio_priv(indio_dev);

	return ((st->pwr_down_mode >> (chan->channel * 2)) & 0x3) - 1;
	}

	static int ad5686_set_powerdown_mode(struct iio_dev *indio_dev,
	const struct iio_chan_spec *chan, unsigned int mode)
	{
	struct ad5686_state *st = iio_priv(indio_dev);

	st->pwr_down_mode &= ~(0x3 << (chan->channel * 2));
	st->pwr_down_mode \|= ((mode + 1) << (chan->channel * 2));

	return 0;
	}

	static const struct iio_enum ad5686_powerdown_mode_enum = {
	.items = ad5686_powerdown_modes,
	.num_items = ARRAY_SIZE(ad5686_powerdown_modes),
	.get = ad5686_get_powerdown_mode,
	.set = ad5686_set_powerdown_mode,
	};

	static ssize_t ad5686_read_dac_powerdown(struct iio_dev *indio_dev,
	uintptr_t private, const struct iio_chan_spec chan, char buf)
	{
	struct ad5686_state *st = iio_priv(indio_dev);

	return sprintf(buf, "%d\n", !!(st->pwr_down_mask &
	(0x3 << (chan->channel * 2))));
	}

	static ssize_t ad5686_write_dac_powerdown(struct iio_dev *indio_dev,
	uintptr_t private, const struct iio_chan_spec chan, const char buf,
	size_t len)
	{
	bool readin;
	int ret;
	struct ad5686_state *st = iio_priv(indio_dev);

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

	if (readin)
	st->pwr_down_mask \|= (0x3 << (chan->channel * 2));
	else
	st->pwr_down_mask &= ~(0x3 << (chan->channel * 2));

	ret = ad5686_spi_write(st, AD5686_CMD_POWERDOWN_DAC, 0,
	st->pwr_down_mask & st->pwr_down_mode, 0);

	return ret ? ret : len;
	}

	static int ad5686_read_raw(struct iio_dev *indio_dev,
	struct iio_chan_spec const *chan,
	int *val,
	int *val2,
	long m)
	{
	struct ad5686_state *st = iio_priv(indio_dev);
	int ret;

	switch (m) {
	case IIO_CHAN_INFO_RAW:
	mutex_lock(&indio_dev->mlock);
	ret = ad5686_spi_read(st, chan->address);
	mutex_unlock(&indio_dev->mlock);
	if (ret < 0)
	return ret;
	*val = ret;
	return IIO_VAL_INT;
	case IIO_CHAN_INFO_SCALE:
	*val = st->vref_mv;
	*val2 = chan->scan_type.realbits;
	return IIO_VAL_FRACTIONAL_LOG2;
	}
	return -EINVAL;
	}

	static int ad5686_write_raw(struct iio_dev *indio_dev,
	struct iio_chan_spec const *chan,
	int val,
	int val2,
	long mask)
	{
	struct ad5686_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 = ad5686_spi_write(st,
	AD5686_CMD_WRITE_INPUT_N_UPDATE_N,
	chan->address,
	val,
	chan->scan_type.shift);
	mutex_unlock(&indio_dev->mlock);
	break;
	default:
	ret = -EINVAL;
	}

	return ret;
	}

	static const struct iio_info ad5686_info = {
	.read_raw = ad5686_read_raw,
	.write_raw = ad5686_write_raw,
	.driver_module = THIS_MODULE,
	};

	static const struct iio_chan_spec_ext_info ad5686_ext_info[] = {
	{
	.name = "powerdown",
	.read = ad5686_read_dac_powerdown,
	.write = ad5686_write_dac_powerdown,
	.shared = IIO_SEPARATE,
	},
	IIO_ENUM("powerdown_mode", IIO_SEPARATE, &ad5686_powerdown_mode_enum),
	IIO_ENUM_AVAILABLE("powerdown_mode", &ad5686_powerdown_mode_enum),
	{ },
	};

	#define AD5868_CHANNEL(chan, bits, _shift) { \
	.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 = AD5686_ADDR_DAC(chan), \
	.scan_type = { \
	.sign = 'u', \
	.realbits = (bits), \
	.storagebits = 16, \
	.shift = (_shift), \
	}, \
	.ext_info = ad5686_ext_info, \
	}

	static const struct ad5686_chip_info ad5686_chip_info_tbl[] = {
	[ID_AD5684] = {
	.channel[0] = AD5868_CHANNEL(0, 12, 4),
	.channel[1] = AD5868_CHANNEL(1, 12, 4),
	.channel[2] = AD5868_CHANNEL(2, 12, 4),
	.channel[3] = AD5868_CHANNEL(3, 12, 4),
	.int_vref_mv = 2500,
	},
	[ID_AD5685] = {
	.channel[0] = AD5868_CHANNEL(0, 14, 2),
	.channel[1] = AD5868_CHANNEL(1, 14, 2),
	.channel[2] = AD5868_CHANNEL(2, 14, 2),
	.channel[3] = AD5868_CHANNEL(3, 14, 2),
	.int_vref_mv = 2500,
	},
	[ID_AD5686] = {
	.channel[0] = AD5868_CHANNEL(0, 16, 0),
	.channel[1] = AD5868_CHANNEL(1, 16, 0),
	.channel[2] = AD5868_CHANNEL(2, 16, 0),
	.channel[3] = AD5868_CHANNEL(3, 16, 0),
	.int_vref_mv = 2500,
	},
	};


	static int ad5686_probe(struct spi_device *spi)
	{
	struct ad5686_state *st;
	struct iio_dev *indio_dev;
	int ret, voltage_uv = 0;

	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->reg = devm_regulator_get_optional(&spi->dev, "vcc");
	if (!IS_ERR(st->reg)) {
	ret = regulator_enable(st->reg);
	if (ret)
	return ret;

	ret = regulator_get_voltage(st->reg);
	if (ret < 0)
	goto error_disable_reg;

	voltage_uv = ret;
	}

	st->chip_info =
	&ad5686_chip_info_tbl[spi_get_device_id(spi)->driver_data];

	if (voltage_uv)
	st->vref_mv = voltage_uv / 1000;
	else
	st->vref_mv = st->chip_info->int_vref_mv;

	st->spi = spi;

	/* Set all the power down mode for all channels to 1K pulldown */
	st->pwr_down_mode = 0x55;

	indio_dev->dev.parent = &spi->dev;
	indio_dev->name = spi_get_device_id(spi)->name;
	indio_dev->info = &ad5686_info;
	indio_dev->modes = INDIO_DIRECT_MODE;
	indio_dev->channels = st->chip_info->channel;
	indio_dev->num_channels = AD5686_DAC_CHANNELS;

	ret = ad5686_spi_write(st, AD5686_CMD_INTERNAL_REFER_SETUP, 0,
	!!voltage_uv, 0);
	if (ret)
	goto error_disable_reg;

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

	return 0;

	error_disable_reg:
	if (!IS_ERR(st->reg))
	regulator_disable(st->reg);
	return ret;
	}

	static int ad5686_remove(struct spi_device *spi)
	{
	struct iio_dev *indio_dev = spi_get_drvdata(spi);
	struct ad5686_state *st = iio_priv(indio_dev);

	iio_device_unregister(indio_dev);
	if (!IS_ERR(st->reg))
	regulator_disable(st->reg);

	return 0;
	}

	static const struct spi_device_id ad5686_id[] = {
	{"ad5684", ID_AD5684},
	{"ad5685", ID_AD5685},
	{"ad5686", ID_AD5686},
	{}
	};
	MODULE_DEVICE_TABLE(spi, ad5686_id);

	static struct spi_driver ad5686_driver = {
	.driver = {
	.name = "ad5686",
	},
	.probe = ad5686_probe,
	.remove = ad5686_remove,
	.id_table = ad5686_id,
	};
	module_spi_driver(ad5686_driver);

	MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
	MODULE_DESCRIPTION("Analog Devices AD5686/85/84 DAC");
	MODULE_LICENSE("GPL v2");