drivers/iio/adc/ad7923.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * AD7904/AD7914/AD7923/AD7924/AD7908/AD7918/AD7928 SPI ADC driver
  *
  * Copyright 2011 Analog Devices Inc (from AD7923 Driver)
  * Copyright 2012 CS Systemes d'Information
  */

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

 #include <linux/iio/iio.h>
 #include <linux/iio/sysfs.h>
 #include <linux/iio/buffer.h>
 #include <linux/iio/trigger_consumer.h>
 #include <linux/iio/triggered_buffer.h>

 #define AD7923_WRITE_CR		BIT(11)		/* write control register */
 #define AD7923_RANGE		BIT(1)		/* range to REFin */
 #define AD7923_CODING		BIT(0)		/* coding is straight binary */
 #define AD7923_PM_MODE_AS	(1)		/* auto shutdown */
 #define AD7923_PM_MODE_FS	(2)		/* full shutdown */
 #define AD7923_PM_MODE_OPS	(3)		/* normal operation */
 #define AD7923_SEQUENCE_OFF	(0)		/* no sequence fonction */
 #define AD7923_SEQUENCE_PROTECT	(2)		/* no interrupt write cycle */
 #define AD7923_SEQUENCE_ON	(3)		/* continuous sequence */


 #define AD7923_PM_MODE_WRITE(mode)	((mode) << 4)	 /* write mode */
 #define AD7923_CHANNEL_WRITE(channel)	((channel) << 6) /* write channel */
 #define AD7923_SEQUENCE_WRITE(sequence)	((((sequence) & 1) << 3) \
 					+ (((sequence) & 2) << 9))
 						/* write sequence fonction */
 /* left shift for CR : bit 11 transmit in first */
 #define AD7923_SHIFT_REGISTER	4

 /* val = value, dec = left shift, bits = number of bits of the mask */
 #define EXTRACT(val, dec, bits)		(((val) >> (dec)) & ((1 << (bits)) - 1))

 struct ad7923_state {
 	struct spi_device		*spi;
 	struct spi_transfer		ring_xfer[5];
 	struct spi_transfer		scan_single_xfer[2];
 	struct spi_message		ring_msg;
 	struct spi_message		scan_single_msg;

 	struct regulator		*reg;

 	unsigned int			settings;

 	/*
 	 * DMA (thus cache coherency maintenance) requires the
 	 * transfer buffers to live in their own cache lines.
 	 */
 	__be16				rx_buf[4] ____cacheline_aligned;
 	__be16				tx_buf[4];
 };

 struct ad7923_chip_info {
 	const struct iio_chan_spec *channels;
 	unsigned int num_channels;
 };

 enum ad7923_id {
 	AD7904,
 	AD7914,
 	AD7924,
 	AD7908,
 	AD7918,
 	AD7928
 };

 #define AD7923_V_CHAN(index, bits)					\
 	{								\
 		.type = IIO_VOLTAGE,					\
 		.indexed = 1,						\
 		.channel = index,					\
 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),		\
 		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),	\
 		.address = index,					\
 		.scan_index = index,					\
 		.scan_type = {						\
 			.sign = 'u',					\
 			.realbits = (bits),				\
 			.storagebits = 16,				\
 			.endianness = IIO_BE,				\
 		},							\
 	}

 #define DECLARE_AD7923_CHANNELS(name, bits) \
 const struct iio_chan_spec name ## _channels[] = { \
 	AD7923_V_CHAN(0, bits), \
 	AD7923_V_CHAN(1, bits), \
 	AD7923_V_CHAN(2, bits), \
 	AD7923_V_CHAN(3, bits), \
 	IIO_CHAN_SOFT_TIMESTAMP(4), \
 }

 #define DECLARE_AD7908_CHANNELS(name, bits) \
 const struct iio_chan_spec name ## _channels[] = { \
 	AD7923_V_CHAN(0, bits), \
 	AD7923_V_CHAN(1, bits), \
 	AD7923_V_CHAN(2, bits), \
 	AD7923_V_CHAN(3, bits), \
 	AD7923_V_CHAN(4, bits), \
 	AD7923_V_CHAN(5, bits), \
 	AD7923_V_CHAN(6, bits), \
 	AD7923_V_CHAN(7, bits), \
 	IIO_CHAN_SOFT_TIMESTAMP(8), \
 }

 static DECLARE_AD7923_CHANNELS(ad7904, 8);
 static DECLARE_AD7923_CHANNELS(ad7914, 10);
 static DECLARE_AD7923_CHANNELS(ad7924, 12);
 static DECLARE_AD7908_CHANNELS(ad7908, 8);
 static DECLARE_AD7908_CHANNELS(ad7918, 10);
 static DECLARE_AD7908_CHANNELS(ad7928, 12);

 static const struct ad7923_chip_info ad7923_chip_info[] = {
 	[AD7904] = {
 		.channels = ad7904_channels,
 		.num_channels = ARRAY_SIZE(ad7904_channels),
 	},
 	[AD7914] = {
 		.channels = ad7914_channels,
 		.num_channels = ARRAY_SIZE(ad7914_channels),
 	},
 	[AD7924] = {
 		.channels = ad7924_channels,
 		.num_channels = ARRAY_SIZE(ad7924_channels),
 	},
 	[AD7908] = {
 		.channels = ad7908_channels,
 		.num_channels = ARRAY_SIZE(ad7908_channels),
 	},
 	[AD7918] = {
 		.channels = ad7918_channels,
 		.num_channels = ARRAY_SIZE(ad7918_channels),
 	},
 	[AD7928] = {
 		.channels = ad7928_channels,
 		.num_channels = ARRAY_SIZE(ad7928_channels),
 	},
 };

 /*
  * ad7923_update_scan_mode() setup the spi transfer buffer for the new scan mask
  */
 static int ad7923_update_scan_mode(struct iio_dev *indio_dev,
 				   const unsigned long *active_scan_mask)
 {
 	struct ad7923_state *st = iio_priv(indio_dev);
 	int i, cmd, len;

 	len = 0;
 	/*
 	 * For this driver the last channel is always the software timestamp so
 	 * skip that one.
 	 */
 	for_each_set_bit(i, active_scan_mask, indio_dev->num_channels - 1) {
 		cmd = AD7923_WRITE_CR | AD7923_CHANNEL_WRITE(i) |
 			AD7923_SEQUENCE_WRITE(AD7923_SEQUENCE_OFF) |
 			st->settings;
 		cmd <<= AD7923_SHIFT_REGISTER;
 		st->tx_buf[len++] = cpu_to_be16(cmd);
 	}
 	/* build spi ring message */
 	st->ring_xfer[0].tx_buf = &st->tx_buf[0];
 	st->ring_xfer[0].len = len;
 	st->ring_xfer[0].cs_change = 1;

 	spi_message_init(&st->ring_msg);
 	spi_message_add_tail(&st->ring_xfer[0], &st->ring_msg);

 	for (i = 0; i < len; i++) {
 		st->ring_xfer[i + 1].rx_buf = &st->rx_buf[i];
 		st->ring_xfer[i + 1].len = 2;
 		st->ring_xfer[i + 1].cs_change = 1;
 		spi_message_add_tail(&st->ring_xfer[i + 1], &st->ring_msg);
 	}
 	/* make sure last transfer cs_change is not set */
 	st->ring_xfer[i + 1].cs_change = 0;

 	return 0;
 }

 /*
  * ad7923_trigger_handler() bh of trigger launched polling to ring buffer
  *
  * Currently there is no option in this driver to disable the saving of
  * timestamps within the ring.
  */
 static irqreturn_t ad7923_trigger_handler(int irq, void *p)
 {
 	struct iio_poll_func *pf = p;
 	struct iio_dev *indio_dev = pf->indio_dev;
 	struct ad7923_state *st = iio_priv(indio_dev);
 	int b_sent;

 	b_sent = spi_sync(st->spi, &st->ring_msg);
 	if (b_sent)
 		goto done;

 	iio_push_to_buffers_with_timestamp(indio_dev, st->rx_buf,
 					   iio_get_time_ns(indio_dev));

 done:
 	iio_trigger_notify_done(indio_dev->trig);

 	return IRQ_HANDLED;
 }

 static int ad7923_scan_direct(struct ad7923_state *st, unsigned int ch)
 {
 	int ret, cmd;

 	cmd = AD7923_WRITE_CR | AD7923_CHANNEL_WRITE(ch) |
 		AD7923_SEQUENCE_WRITE(AD7923_SEQUENCE_OFF) |
 		st->settings;
 	cmd <<= AD7923_SHIFT_REGISTER;
 	st->tx_buf[0] = cpu_to_be16(cmd);

 	ret = spi_sync(st->spi, &st->scan_single_msg);
 	if (ret)
 		return ret;

 	return be16_to_cpu(st->rx_buf[0]);
 }

 static int ad7923_get_range(struct ad7923_state *st)
 {
 	int vref;

 	vref = regulator_get_voltage(st->reg);
 	if (vref < 0)
 		return vref;

 	vref /= 1000;

 	if (!(st->settings & AD7923_RANGE))
 		vref *= 2;

 	return vref;
 }

 static int ad7923_read_raw(struct iio_dev *indio_dev,
 			   struct iio_chan_spec const *chan,
 			   int *val,
 			   int *val2,
 			   long m)
 {
 	int ret;
 	struct ad7923_state *st = iio_priv(indio_dev);

 	switch (m) {
 	case IIO_CHAN_INFO_RAW:
 		ret = iio_device_claim_direct_mode(indio_dev);
 		if (ret)
 			return ret;
 		ret = ad7923_scan_direct(st, chan->address);
 		iio_device_release_direct_mode(indio_dev);

 		if (ret < 0)
 			return ret;

 		if (chan->address == EXTRACT(ret, 12, 4))
 			*val = EXTRACT(ret, 0, 12);
 		else
 			return -EIO;

 		return IIO_VAL_INT;
 	case IIO_CHAN_INFO_SCALE:
 		ret = ad7923_get_range(st);
 		if (ret < 0)
 			return ret;
 		*val = ret;
 		*val2 = chan->scan_type.realbits;
 		return IIO_VAL_FRACTIONAL_LOG2;
 	}
 	return -EINVAL;
 }

 static const struct iio_info ad7923_info = {
 	.read_raw = &ad7923_read_raw,
 	.update_scan_mode = ad7923_update_scan_mode,
 };

 static int ad7923_probe(struct spi_device *spi)
 {
 	struct ad7923_state *st;
 	struct iio_dev *indio_dev;
 	const struct ad7923_chip_info *info;
 	int ret;

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

 	st = iio_priv(indio_dev);

 	spi_set_drvdata(spi, indio_dev);

 	st->spi = spi;
 	st->settings = AD7923_CODING | AD7923_RANGE |
 			AD7923_PM_MODE_WRITE(AD7923_PM_MODE_OPS);

 	info = &ad7923_chip_info[spi_get_device_id(spi)->driver_data];

 	indio_dev->name = spi_get_device_id(spi)->name;
 	indio_dev->modes = INDIO_DIRECT_MODE;
 	indio_dev->channels = info->channels;
 	indio_dev->num_channels = info->num_channels;
 	indio_dev->info = &ad7923_info;

 	/* Setup default message */

 	st->scan_single_xfer[0].tx_buf = &st->tx_buf[0];
 	st->scan_single_xfer[0].len = 2;
 	st->scan_single_xfer[0].cs_change = 1;
 	st->scan_single_xfer[1].rx_buf = &st->rx_buf[0];
 	st->scan_single_xfer[1].len = 2;

 	spi_message_init(&st->scan_single_msg);
 	spi_message_add_tail(&st->scan_single_xfer[0], &st->scan_single_msg);
 	spi_message_add_tail(&st->scan_single_xfer[1], &st->scan_single_msg);

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

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

 	ret = iio_triggered_buffer_setup(indio_dev, NULL,
 					 &ad7923_trigger_handler, NULL);
 	if (ret)
 		goto error_disable_reg;

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

 	return 0;

 error_cleanup_ring:
 	iio_triggered_buffer_cleanup(indio_dev);
 error_disable_reg:
 	regulator_disable(st->reg);

 	return ret;
 }

 static int ad7923_remove(struct spi_device *spi)
 {
 	struct iio_dev *indio_dev = spi_get_drvdata(spi);
 	struct ad7923_state *st = iio_priv(indio_dev);

 	iio_device_unregister(indio_dev);
 	iio_triggered_buffer_cleanup(indio_dev);
 	regulator_disable(st->reg);

 	return 0;
 }

 static const struct spi_device_id ad7923_id[] = {
 	{"ad7904", AD7904},
 	{"ad7914", AD7914},
 	{"ad7923", AD7924},
 	{"ad7924", AD7924},
 	{"ad7908", AD7908},
 	{"ad7918", AD7918},
 	{"ad7928", AD7928},
 	{}
 };
 MODULE_DEVICE_TABLE(spi, ad7923_id);

 static const struct of_device_id ad7923_of_match[] = {
 	{ .compatible = "adi,ad7904", },
 	{ .compatible = "adi,ad7914", },
 	{ .compatible = "adi,ad7923", },
 	{ .compatible = "adi,ad7924", },
 	{ .compatible = "adi,ad7908", },
 	{ .compatible = "adi,ad7918", },
 	{ .compatible = "adi,ad7928", },
 	{ },
 };
 MODULE_DEVICE_TABLE(of, ad7923_of_match);

 static struct spi_driver ad7923_driver = {
 	.driver = {
 		.name	= "ad7923",
 		.of_match_table = ad7923_of_match,
 	},
 	.probe		= ad7923_probe,
 	.remove		= ad7923_remove,
 	.id_table	= ad7923_id,
 };
 module_spi_driver(ad7923_driver);

 MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
 MODULE_AUTHOR("Patrick Vasseur <patrick.vasseur@c-s.fr>");
 MODULE_DESCRIPTION("Analog Devices AD7923 and similar ADC");
 MODULE_LICENSE("GPL v2");
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* AD7904/AD7914/AD7923/AD7924/AD7908/AD7918/AD7928 SPI ADC driver
	*
	* Copyright 2011 Analog Devices Inc (from AD7923 Driver)
	* Copyright 2012 CS Systemes d'Information
	*/

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

	#include <linux/iio/iio.h>
	#include <linux/iio/sysfs.h>
	#include <linux/iio/buffer.h>
	#include <linux/iio/trigger_consumer.h>
	#include <linux/iio/triggered_buffer.h>

	#define AD7923_WRITE_CR BIT(11) /* write control register */
	#define AD7923_RANGE BIT(1) /* range to REFin */
	#define AD7923_CODING BIT(0) /* coding is straight binary */
	#define AD7923_PM_MODE_AS (1) /* auto shutdown */
	#define AD7923_PM_MODE_FS (2) /* full shutdown */
	#define AD7923_PM_MODE_OPS (3) /* normal operation */
	#define AD7923_SEQUENCE_OFF (0) /* no sequence fonction */
	#define AD7923_SEQUENCE_PROTECT (2) /* no interrupt write cycle */
	#define AD7923_SEQUENCE_ON (3) /* continuous sequence */


	#define AD7923_PM_MODE_WRITE(mode) ((mode) << 4) /* write mode */
	#define AD7923_CHANNEL_WRITE(channel) ((channel) << 6) /* write channel */
	#define AD7923_SEQUENCE_WRITE(sequence) ((((sequence) & 1) << 3) \
	+ (((sequence) & 2) << 9))
	/* write sequence fonction */
	/* left shift for CR : bit 11 transmit in first */
	#define AD7923_SHIFT_REGISTER 4

	/* val = value, dec = left shift, bits = number of bits of the mask */
	#define EXTRACT(val, dec, bits) (((val) >> (dec)) & ((1 << (bits)) - 1))

	struct ad7923_state {
	struct spi_device *spi;
	struct spi_transfer ring_xfer[5];
	struct spi_transfer scan_single_xfer[2];
	struct spi_message ring_msg;
	struct spi_message scan_single_msg;

	struct regulator *reg;

	unsigned int settings;

	/*
	* DMA (thus cache coherency maintenance) requires the
	* transfer buffers to live in their own cache lines.
	*/
	__be16 rx_buf[4] ____cacheline_aligned;
	__be16 tx_buf[4];
	};

	struct ad7923_chip_info {
	const struct iio_chan_spec *channels;
	unsigned int num_channels;
	};

	enum ad7923_id {
	AD7904,
	AD7914,
	AD7924,
	AD7908,
	AD7918,
	AD7928
	};

	#define AD7923_V_CHAN(index, bits) \
	{ \
	.type = IIO_VOLTAGE, \
	.indexed = 1, \
	.channel = index, \
	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
	.address = index, \
	.scan_index = index, \
	.scan_type = { \
	.sign = 'u', \
	.realbits = (bits), \
	.storagebits = 16, \
	.endianness = IIO_BE, \
	}, \
	}

	#define DECLARE_AD7923_CHANNELS(name, bits) \
	const struct iio_chan_spec name ## _channels[] = { \
	AD7923_V_CHAN(0, bits), \
	AD7923_V_CHAN(1, bits), \
	AD7923_V_CHAN(2, bits), \
	AD7923_V_CHAN(3, bits), \
	IIO_CHAN_SOFT_TIMESTAMP(4), \
	}

	#define DECLARE_AD7908_CHANNELS(name, bits) \
	const struct iio_chan_spec name ## _channels[] = { \
	AD7923_V_CHAN(0, bits), \
	AD7923_V_CHAN(1, bits), \
	AD7923_V_CHAN(2, bits), \
	AD7923_V_CHAN(3, bits), \
	AD7923_V_CHAN(4, bits), \
	AD7923_V_CHAN(5, bits), \
	AD7923_V_CHAN(6, bits), \
	AD7923_V_CHAN(7, bits), \
	IIO_CHAN_SOFT_TIMESTAMP(8), \
	}

	static DECLARE_AD7923_CHANNELS(ad7904, 8);
	static DECLARE_AD7923_CHANNELS(ad7914, 10);
	static DECLARE_AD7923_CHANNELS(ad7924, 12);
	static DECLARE_AD7908_CHANNELS(ad7908, 8);
	static DECLARE_AD7908_CHANNELS(ad7918, 10);
	static DECLARE_AD7908_CHANNELS(ad7928, 12);

	static const struct ad7923_chip_info ad7923_chip_info[] = {
	[AD7904] = {
	.channels = ad7904_channels,
	.num_channels = ARRAY_SIZE(ad7904_channels),
	},
	[AD7914] = {
	.channels = ad7914_channels,
	.num_channels = ARRAY_SIZE(ad7914_channels),
	},
	[AD7924] = {
	.channels = ad7924_channels,
	.num_channels = ARRAY_SIZE(ad7924_channels),
	},
	[AD7908] = {
	.channels = ad7908_channels,
	.num_channels = ARRAY_SIZE(ad7908_channels),
	},
	[AD7918] = {
	.channels = ad7918_channels,
	.num_channels = ARRAY_SIZE(ad7918_channels),
	},
	[AD7928] = {
	.channels = ad7928_channels,
	.num_channels = ARRAY_SIZE(ad7928_channels),
	},
	};

	/*
	* ad7923_update_scan_mode() setup the spi transfer buffer for the new scan mask
	*/
	static int ad7923_update_scan_mode(struct iio_dev *indio_dev,
	const unsigned long *active_scan_mask)
	{
	struct ad7923_state *st = iio_priv(indio_dev);
	int i, cmd, len;

	len = 0;
	/*
	* For this driver the last channel is always the software timestamp so
	* skip that one.
	*/
	for_each_set_bit(i, active_scan_mask, indio_dev->num_channels - 1) {
	cmd = AD7923_WRITE_CR \| AD7923_CHANNEL_WRITE(i) \|
	AD7923_SEQUENCE_WRITE(AD7923_SEQUENCE_OFF) \|
	st->settings;
	cmd <<= AD7923_SHIFT_REGISTER;
	st->tx_buf[len++] = cpu_to_be16(cmd);
	}
	/* build spi ring message */
	st->ring_xfer[0].tx_buf = &st->tx_buf[0];
	st->ring_xfer[0].len = len;
	st->ring_xfer[0].cs_change = 1;

	spi_message_init(&st->ring_msg);
	spi_message_add_tail(&st->ring_xfer[0], &st->ring_msg);

	for (i = 0; i < len; i++) {
	st->ring_xfer[i + 1].rx_buf = &st->rx_buf[i];
	st->ring_xfer[i + 1].len = 2;
	st->ring_xfer[i + 1].cs_change = 1;
	spi_message_add_tail(&st->ring_xfer[i + 1], &st->ring_msg);
	}
	/* make sure last transfer cs_change is not set */
	st->ring_xfer[i + 1].cs_change = 0;

	return 0;
	}

	/*
	* ad7923_trigger_handler() bh of trigger launched polling to ring buffer
	*
	* Currently there is no option in this driver to disable the saving of
	* timestamps within the ring.
	*/
	static irqreturn_t ad7923_trigger_handler(int irq, void *p)
	{
	struct iio_poll_func *pf = p;
	struct iio_dev *indio_dev = pf->indio_dev;
	struct ad7923_state *st = iio_priv(indio_dev);
	int b_sent;

	b_sent = spi_sync(st->spi, &st->ring_msg);
	if (b_sent)
	goto done;

	iio_push_to_buffers_with_timestamp(indio_dev, st->rx_buf,
	iio_get_time_ns(indio_dev));

	done:
	iio_trigger_notify_done(indio_dev->trig);

	return IRQ_HANDLED;
	}

	static int ad7923_scan_direct(struct ad7923_state *st, unsigned int ch)
	{
	int ret, cmd;

	cmd = AD7923_WRITE_CR \| AD7923_CHANNEL_WRITE(ch) \|
	AD7923_SEQUENCE_WRITE(AD7923_SEQUENCE_OFF) \|
	st->settings;
	cmd <<= AD7923_SHIFT_REGISTER;
	st->tx_buf[0] = cpu_to_be16(cmd);

	ret = spi_sync(st->spi, &st->scan_single_msg);
	if (ret)
	return ret;

	return be16_to_cpu(st->rx_buf[0]);
	}

	static int ad7923_get_range(struct ad7923_state *st)
	{
	int vref;

	vref = regulator_get_voltage(st->reg);
	if (vref < 0)
	return vref;

	vref /= 1000;

	if (!(st->settings & AD7923_RANGE))
	vref *= 2;

	return vref;
	}

	static int ad7923_read_raw(struct iio_dev *indio_dev,
	struct iio_chan_spec const *chan,
	int *val,
	int *val2,
	long m)
	{
	int ret;
	struct ad7923_state *st = iio_priv(indio_dev);

	switch (m) {
	case IIO_CHAN_INFO_RAW:
	ret = iio_device_claim_direct_mode(indio_dev);
	if (ret)
	return ret;
	ret = ad7923_scan_direct(st, chan->address);
	iio_device_release_direct_mode(indio_dev);

	if (ret < 0)
	return ret;

	if (chan->address == EXTRACT(ret, 12, 4))
	*val = EXTRACT(ret, 0, 12);
	else
	return -EIO;

	return IIO_VAL_INT;
	case IIO_CHAN_INFO_SCALE:
	ret = ad7923_get_range(st);
	if (ret < 0)
	return ret;
	*val = ret;
	*val2 = chan->scan_type.realbits;
	return IIO_VAL_FRACTIONAL_LOG2;
	}
	return -EINVAL;
	}

	static const struct iio_info ad7923_info = {
	.read_raw = &ad7923_read_raw,
	.update_scan_mode = ad7923_update_scan_mode,
	};

	static int ad7923_probe(struct spi_device *spi)
	{
	struct ad7923_state *st;
	struct iio_dev *indio_dev;
	const struct ad7923_chip_info *info;
	int ret;

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

	st = iio_priv(indio_dev);

	spi_set_drvdata(spi, indio_dev);

	st->spi = spi;
	st->settings = AD7923_CODING \| AD7923_RANGE \|
	AD7923_PM_MODE_WRITE(AD7923_PM_MODE_OPS);

	info = &ad7923_chip_info[spi_get_device_id(spi)->driver_data];

	indio_dev->name = spi_get_device_id(spi)->name;
	indio_dev->modes = INDIO_DIRECT_MODE;
	indio_dev->channels = info->channels;
	indio_dev->num_channels = info->num_channels;
	indio_dev->info = &ad7923_info;

	/* Setup default message */

	st->scan_single_xfer[0].tx_buf = &st->tx_buf[0];
	st->scan_single_xfer[0].len = 2;
	st->scan_single_xfer[0].cs_change = 1;
	st->scan_single_xfer[1].rx_buf = &st->rx_buf[0];
	st->scan_single_xfer[1].len = 2;

	spi_message_init(&st->scan_single_msg);
	spi_message_add_tail(&st->scan_single_xfer[0], &st->scan_single_msg);
	spi_message_add_tail(&st->scan_single_xfer[1], &st->scan_single_msg);

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

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

	ret = iio_triggered_buffer_setup(indio_dev, NULL,
	&ad7923_trigger_handler, NULL);
	if (ret)
	goto error_disable_reg;

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

	return 0;

	error_cleanup_ring:
	iio_triggered_buffer_cleanup(indio_dev);
	error_disable_reg:
	regulator_disable(st->reg);

	return ret;
	}

	static int ad7923_remove(struct spi_device *spi)
	{
	struct iio_dev *indio_dev = spi_get_drvdata(spi);
	struct ad7923_state *st = iio_priv(indio_dev);

	iio_device_unregister(indio_dev);
	iio_triggered_buffer_cleanup(indio_dev);
	regulator_disable(st->reg);

	return 0;
	}

	static const struct spi_device_id ad7923_id[] = {
	{"ad7904", AD7904},
	{"ad7914", AD7914},
	{"ad7923", AD7924},
	{"ad7924", AD7924},
	{"ad7908", AD7908},
	{"ad7918", AD7918},
	{"ad7928", AD7928},
	{}
	};
	MODULE_DEVICE_TABLE(spi, ad7923_id);

	static const struct of_device_id ad7923_of_match[] = {
	{ .compatible = "adi,ad7904", },
	{ .compatible = "adi,ad7914", },
	{ .compatible = "adi,ad7923", },
	{ .compatible = "adi,ad7924", },
	{ .compatible = "adi,ad7908", },
	{ .compatible = "adi,ad7918", },
	{ .compatible = "adi,ad7928", },
	{ },
	};
	MODULE_DEVICE_TABLE(of, ad7923_of_match);

	static struct spi_driver ad7923_driver = {
	.driver = {
	.name = "ad7923",
	.of_match_table = ad7923_of_match,
	},
	.probe = ad7923_probe,
	.remove = ad7923_remove,
	.id_table = ad7923_id,
	};
	module_spi_driver(ad7923_driver);

	MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
	MODULE_AUTHOR("Patrick Vasseur <patrick.vasseur@c-s.fr>");
	MODULE_DESCRIPTION("Analog Devices AD7923 and similar ADC");
	MODULE_LICENSE("GPL v2");