drivers/iio/adc/ad7266.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * AD7266/65 SPI ADC driver
  *
  * Copyright 2012 Analog Devices Inc.
  */

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

 #include <linux/interrupt.h>

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

 #include <linux/platform_data/ad7266.h>

 struct ad7266_state {
 	struct spi_device	*spi;
 	struct regulator	*reg;
 	unsigned long		vref_mv;

 	struct spi_transfer	single_xfer[3];
 	struct spi_message	single_msg;

 	enum ad7266_range	range;
 	enum ad7266_mode	mode;
 	bool			fixed_addr;
 	struct gpio_desc	*gpios[3];

 	/*
 	 * DMA (thus cache coherency maintenance) requires the
 	 * transfer buffers to live in their own cache lines.
 	 * The buffer needs to be large enough to hold two samples (4 bytes) and
 	 * the naturally aligned timestamp (8 bytes).
 	 */
 	struct {
 		__be16 sample[2];
 		s64 timestamp;
 	} data ____cacheline_aligned;
 };

 static int ad7266_wakeup(struct ad7266_state *st)
 {
 	/* Any read with >= 2 bytes will wake the device */
 	return spi_read(st->spi, &st->data.sample[0], 2);
 }

 static int ad7266_powerdown(struct ad7266_state *st)
 {
 	/* Any read with < 2 bytes will powerdown the device */
 	return spi_read(st->spi, &st->data.sample[0], 1);
 }

 static int ad7266_preenable(struct iio_dev *indio_dev)
 {
 	struct ad7266_state *st = iio_priv(indio_dev);
 	return ad7266_wakeup(st);
 }

 static int ad7266_postdisable(struct iio_dev *indio_dev)
 {
 	struct ad7266_state *st = iio_priv(indio_dev);
 	return ad7266_powerdown(st);
 }

 static const struct iio_buffer_setup_ops iio_triggered_buffer_setup_ops = {
 	.preenable = &ad7266_preenable,
 	.postenable = &iio_triggered_buffer_postenable,
 	.predisable = &iio_triggered_buffer_predisable,
 	.postdisable = &ad7266_postdisable,
 };

 static irqreturn_t ad7266_trigger_handler(int irq, void *p)
 {
 	struct iio_poll_func *pf = p;
 	struct iio_dev *indio_dev = pf->indio_dev;
 	struct ad7266_state *st = iio_priv(indio_dev);
 	int ret;

 	ret = spi_read(st->spi, st->data.sample, 4);
 	if (ret == 0) {
 		iio_push_to_buffers_with_timestamp(indio_dev, &st->data,
 			    pf->timestamp);
 	}

 	iio_trigger_notify_done(indio_dev->trig);

 	return IRQ_HANDLED;
 }

 static void ad7266_select_input(struct ad7266_state *st, unsigned int nr)
 {
 	unsigned int i;

 	if (st->fixed_addr)
 		return;

 	switch (st->mode) {
 	case AD7266_MODE_SINGLE_ENDED:
 		nr >>= 1;
 		break;
 	case AD7266_MODE_PSEUDO_DIFF:
 		nr |= 1;
 		break;
 	case AD7266_MODE_DIFF:
 		nr &= ~1;
 		break;
 	}

 	for (i = 0; i < 3; ++i)
 		gpiod_set_value(st->gpios[i], (bool)(nr & BIT(i)));
 }

 static int ad7266_update_scan_mode(struct iio_dev *indio_dev,
 	const unsigned long *scan_mask)
 {
 	struct ad7266_state *st = iio_priv(indio_dev);
 	unsigned int nr = find_first_bit(scan_mask, indio_dev->masklength);

 	ad7266_select_input(st, nr);

 	return 0;
 }

 static int ad7266_read_single(struct ad7266_state *st, int *val,
 	unsigned int address)
 {
 	int ret;

 	ad7266_select_input(st, address);

 	ret = spi_sync(st->spi, &st->single_msg);
 	*val = be16_to_cpu(st->data.sample[address % 2]);

 	return ret;
 }

 static int ad7266_read_raw(struct iio_dev *indio_dev,
 	struct iio_chan_spec const *chan, int *val, int *val2, long m)
 {
 	struct ad7266_state *st = iio_priv(indio_dev);
 	unsigned long scale_mv;
 	int ret;

 	switch (m) {
 	case IIO_CHAN_INFO_RAW:
 		ret = iio_device_claim_direct_mode(indio_dev);
 		if (ret)
 			return ret;
 		ret = ad7266_read_single(st, val, chan->address);
 		iio_device_release_direct_mode(indio_dev);

 		*val = (*val >> 2) & 0xfff;
 		if (chan->scan_type.sign == 's')
 			*val = sign_extend32(*val, 11);

 		return IIO_VAL_INT;
 	case IIO_CHAN_INFO_SCALE:
 		scale_mv = st->vref_mv;
 		if (st->mode == AD7266_MODE_DIFF)
 			scale_mv *= 2;
 		if (st->range == AD7266_RANGE_2VREF)
 			scale_mv *= 2;

 		*val = scale_mv;
 		*val2 = chan->scan_type.realbits;
 		return IIO_VAL_FRACTIONAL_LOG2;
 	case IIO_CHAN_INFO_OFFSET:
 		if (st->range == AD7266_RANGE_2VREF &&
 			st->mode != AD7266_MODE_DIFF)
 			*val = 2048;
 		else
 			*val = 0;
 		return IIO_VAL_INT;
 	}
 	return -EINVAL;
 }

 #define AD7266_CHAN(_chan, _sign) {			\
 	.type = IIO_VOLTAGE,				\
 	.indexed = 1,					\
 	.channel = (_chan),				\
 	.address = (_chan),				\
 	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),	\
 	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \
 		| BIT(IIO_CHAN_INFO_OFFSET),			\
 	.scan_index = (_chan),				\
 	.scan_type = {					\
 		.sign = (_sign),			\
 		.realbits = 12,				\
 		.storagebits = 16,			\
 		.shift = 2,				\
 		.endianness = IIO_BE,			\
 	},						\
 }

 #define AD7266_DECLARE_SINGLE_ENDED_CHANNELS(_name, _sign) \
 const struct iio_chan_spec ad7266_channels_##_name[] = { \
 	AD7266_CHAN(0, (_sign)), \
 	AD7266_CHAN(1, (_sign)), \
 	AD7266_CHAN(2, (_sign)), \
 	AD7266_CHAN(3, (_sign)), \
 	AD7266_CHAN(4, (_sign)), \
 	AD7266_CHAN(5, (_sign)), \
 	AD7266_CHAN(6, (_sign)), \
 	AD7266_CHAN(7, (_sign)), \
 	AD7266_CHAN(8, (_sign)), \
 	AD7266_CHAN(9, (_sign)), \
 	AD7266_CHAN(10, (_sign)), \
 	AD7266_CHAN(11, (_sign)), \
 	IIO_CHAN_SOFT_TIMESTAMP(13), \
 }

 #define AD7266_DECLARE_SINGLE_ENDED_CHANNELS_FIXED(_name, _sign) \
 const struct iio_chan_spec ad7266_channels_##_name##_fixed[] = { \
 	AD7266_CHAN(0, (_sign)), \
 	AD7266_CHAN(1, (_sign)), \
 	IIO_CHAN_SOFT_TIMESTAMP(2), \
 }

 static AD7266_DECLARE_SINGLE_ENDED_CHANNELS(u, 'u');
 static AD7266_DECLARE_SINGLE_ENDED_CHANNELS(s, 's');
 static AD7266_DECLARE_SINGLE_ENDED_CHANNELS_FIXED(u, 'u');
 static AD7266_DECLARE_SINGLE_ENDED_CHANNELS_FIXED(s, 's');

 #define AD7266_CHAN_DIFF(_chan, _sign) {			\
 	.type = IIO_VOLTAGE,				\
 	.indexed = 1,					\
 	.channel = (_chan) * 2,				\
 	.channel2 = (_chan) * 2 + 1,			\
 	.address = (_chan),				\
 	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),	\
 	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE)	\
 		| BIT(IIO_CHAN_INFO_OFFSET),			\
 	.scan_index = (_chan),				\
 	.scan_type = {					\
 		.sign = _sign,			\
 		.realbits = 12,				\
 		.storagebits = 16,			\
 		.shift = 2,				\
 		.endianness = IIO_BE,			\
 	},						\
 	.differential = 1,				\
 }

 #define AD7266_DECLARE_DIFF_CHANNELS(_name, _sign) \
 const struct iio_chan_spec ad7266_channels_diff_##_name[] = { \
 	AD7266_CHAN_DIFF(0, (_sign)), \
 	AD7266_CHAN_DIFF(1, (_sign)), \
 	AD7266_CHAN_DIFF(2, (_sign)), \
 	AD7266_CHAN_DIFF(3, (_sign)), \
 	AD7266_CHAN_DIFF(4, (_sign)), \
 	AD7266_CHAN_DIFF(5, (_sign)), \
 	IIO_CHAN_SOFT_TIMESTAMP(6), \
 }

 static AD7266_DECLARE_DIFF_CHANNELS(s, 's');
 static AD7266_DECLARE_DIFF_CHANNELS(u, 'u');

 #define AD7266_DECLARE_DIFF_CHANNELS_FIXED(_name, _sign) \
 const struct iio_chan_spec ad7266_channels_diff_fixed_##_name[] = { \
 	AD7266_CHAN_DIFF(0, (_sign)), \
 	AD7266_CHAN_DIFF(1, (_sign)), \
 	IIO_CHAN_SOFT_TIMESTAMP(2), \
 }

 static AD7266_DECLARE_DIFF_CHANNELS_FIXED(s, 's');
 static AD7266_DECLARE_DIFF_CHANNELS_FIXED(u, 'u');

 static const struct iio_info ad7266_info = {
 	.read_raw = &ad7266_read_raw,
 	.update_scan_mode = &ad7266_update_scan_mode,
 };

 static const unsigned long ad7266_available_scan_masks[] = {
 	0x003,
 	0x00c,
 	0x030,
 	0x0c0,
 	0x300,
 	0xc00,
 	0x000,
 };

 static const unsigned long ad7266_available_scan_masks_diff[] = {
 	0x003,
 	0x00c,
 	0x030,
 	0x000,
 };

 static const unsigned long ad7266_available_scan_masks_fixed[] = {
 	0x003,
 	0x000,
 };

 struct ad7266_chan_info {
 	const struct iio_chan_spec *channels;
 	unsigned int num_channels;
 	const unsigned long *scan_masks;
 };

 #define AD7266_CHAN_INFO_INDEX(_differential, _signed, _fixed) \
 	(((_differential) << 2) | ((_signed) << 1) | ((_fixed) << 0))

 static const struct ad7266_chan_info ad7266_chan_infos[] = {
 	[AD7266_CHAN_INFO_INDEX(0, 0, 0)] = {
 		.channels = ad7266_channels_u,
 		.num_channels = ARRAY_SIZE(ad7266_channels_u),
 		.scan_masks = ad7266_available_scan_masks,
 	},
 	[AD7266_CHAN_INFO_INDEX(0, 0, 1)] = {
 		.channels = ad7266_channels_u_fixed,
 		.num_channels = ARRAY_SIZE(ad7266_channels_u_fixed),
 		.scan_masks = ad7266_available_scan_masks_fixed,
 	},
 	[AD7266_CHAN_INFO_INDEX(0, 1, 0)] = {
 		.channels = ad7266_channels_s,
 		.num_channels = ARRAY_SIZE(ad7266_channels_s),
 		.scan_masks = ad7266_available_scan_masks,
 	},
 	[AD7266_CHAN_INFO_INDEX(0, 1, 1)] = {
 		.channels = ad7266_channels_s_fixed,
 		.num_channels = ARRAY_SIZE(ad7266_channels_s_fixed),
 		.scan_masks = ad7266_available_scan_masks_fixed,
 	},
 	[AD7266_CHAN_INFO_INDEX(1, 0, 0)] = {
 		.channels = ad7266_channels_diff_u,
 		.num_channels = ARRAY_SIZE(ad7266_channels_diff_u),
 		.scan_masks = ad7266_available_scan_masks_diff,
 	},
 	[AD7266_CHAN_INFO_INDEX(1, 0, 1)] = {
 		.channels = ad7266_channels_diff_fixed_u,
 		.num_channels = ARRAY_SIZE(ad7266_channels_diff_fixed_u),
 		.scan_masks = ad7266_available_scan_masks_fixed,
 	},
 	[AD7266_CHAN_INFO_INDEX(1, 1, 0)] = {
 		.channels = ad7266_channels_diff_s,
 		.num_channels = ARRAY_SIZE(ad7266_channels_diff_s),
 		.scan_masks = ad7266_available_scan_masks_diff,
 	},
 	[AD7266_CHAN_INFO_INDEX(1, 1, 1)] = {
 		.channels = ad7266_channels_diff_fixed_s,
 		.num_channels = ARRAY_SIZE(ad7266_channels_diff_fixed_s),
 		.scan_masks = ad7266_available_scan_masks_fixed,
 	},
 };

 static void ad7266_init_channels(struct iio_dev *indio_dev)
 {
 	struct ad7266_state *st = iio_priv(indio_dev);
 	bool is_differential, is_signed;
 	const struct ad7266_chan_info *chan_info;
 	int i;

 	is_differential = st->mode != AD7266_MODE_SINGLE_ENDED;
 	is_signed = (st->range == AD7266_RANGE_2VREF) |
 		    (st->mode == AD7266_MODE_DIFF);

 	i = AD7266_CHAN_INFO_INDEX(is_differential, is_signed, st->fixed_addr);
 	chan_info = &ad7266_chan_infos[i];

 	indio_dev->channels = chan_info->channels;
 	indio_dev->num_channels = chan_info->num_channels;
 	indio_dev->available_scan_masks = chan_info->scan_masks;
 	indio_dev->masklength = chan_info->num_channels - 1;
 }

 static const char * const ad7266_gpio_labels[] = {
 	"ad0", "ad1", "ad2",
 };

 static int ad7266_probe(struct spi_device *spi)
 {
 	struct ad7266_platform_data *pdata = spi->dev.platform_data;
 	struct iio_dev *indio_dev;
 	struct ad7266_state *st;
 	unsigned int i;
 	int ret;

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

 	st = iio_priv(indio_dev);

 	st->reg = devm_regulator_get_optional(&spi->dev, "vref");
 	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;

 		st->vref_mv = ret / 1000;
 	} else {
 		/* Any other error indicates that the regulator does exist */
 		if (PTR_ERR(st->reg) != -ENODEV)
 			return PTR_ERR(st->reg);
 		/* Use internal reference */
 		st->vref_mv = 2500;
 	}

 	if (pdata) {
 		st->fixed_addr = pdata->fixed_addr;
 		st->mode = pdata->mode;
 		st->range = pdata->range;

 		if (!st->fixed_addr) {
 			for (i = 0; i < ARRAY_SIZE(st->gpios); ++i) {
 				st->gpios[i] = devm_gpiod_get(&spi->dev,
 						      ad7266_gpio_labels[i],
 						      GPIOD_OUT_LOW);
 				if (IS_ERR(st->gpios[i])) {
 					ret = PTR_ERR(st->gpios[i]);
 					goto error_disable_reg;
 				}
 			}
 		}
 	} else {
 		st->fixed_addr = true;
 		st->range = AD7266_RANGE_VREF;
 		st->mode = AD7266_MODE_DIFF;
 	}

 	spi_set_drvdata(spi, indio_dev);
 	st->spi = spi;

 	indio_dev->dev.parent = &spi->dev;
 	indio_dev->dev.of_node = spi->dev.of_node;
 	indio_dev->name = spi_get_device_id(spi)->name;
 	indio_dev->modes = INDIO_DIRECT_MODE;
 	indio_dev->info = &ad7266_info;

 	ad7266_init_channels(indio_dev);

 	/* wakeup */
 	st->single_xfer[0].rx_buf = &st->data.sample[0];
 	st->single_xfer[0].len = 2;
 	st->single_xfer[0].cs_change = 1;
 	/* conversion */
 	st->single_xfer[1].rx_buf = st->data.sample;
 	st->single_xfer[1].len = 4;
 	st->single_xfer[1].cs_change = 1;
 	/* powerdown */
 	st->single_xfer[2].tx_buf = &st->data.sample[0];
 	st->single_xfer[2].len = 1;

 	spi_message_init(&st->single_msg);
 	spi_message_add_tail(&st->single_xfer[0], &st->single_msg);
 	spi_message_add_tail(&st->single_xfer[1], &st->single_msg);
 	spi_message_add_tail(&st->single_xfer[2], &st->single_msg);

 	ret = iio_triggered_buffer_setup(indio_dev, &iio_pollfunc_store_time,
 		&ad7266_trigger_handler, &iio_triggered_buffer_setup_ops);
 	if (ret)
 		goto error_disable_reg;

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

 	return 0;

 error_buffer_cleanup:
 	iio_triggered_buffer_cleanup(indio_dev);
 error_disable_reg:
 	if (!IS_ERR(st->reg))
 		regulator_disable(st->reg);

 	return ret;
 }

 static int ad7266_remove(struct spi_device *spi)
 {
 	struct iio_dev *indio_dev = spi_get_drvdata(spi);
 	struct ad7266_state *st = iio_priv(indio_dev);

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

 	return 0;
 }

 static const struct spi_device_id ad7266_id[] = {
 	{"ad7265", 0},
 	{"ad7266", 0},
 	{ }
 };
 MODULE_DEVICE_TABLE(spi, ad7266_id);

 static struct spi_driver ad7266_driver = {
 	.driver = {
 		.name	= "ad7266",
 	},
 	.probe		= ad7266_probe,
 	.remove		= ad7266_remove,
 	.id_table	= ad7266_id,
 };
 module_spi_driver(ad7266_driver);

 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
 MODULE_DESCRIPTION("Analog Devices AD7266/65 ADC");
 MODULE_LICENSE("GPL v2");
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* AD7266/65 SPI ADC driver
	*
	* Copyright 2012 Analog Devices Inc.
	*/

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

	#include <linux/interrupt.h>

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

	#include <linux/platform_data/ad7266.h>

	struct ad7266_state {
	struct spi_device *spi;
	struct regulator *reg;
	unsigned long vref_mv;

	struct spi_transfer single_xfer[3];
	struct spi_message single_msg;

	enum ad7266_range range;
	enum ad7266_mode mode;
	bool fixed_addr;
	struct gpio_desc *gpios[3];

	/*
	* DMA (thus cache coherency maintenance) requires the
	* transfer buffers to live in their own cache lines.
	* The buffer needs to be large enough to hold two samples (4 bytes) and
	* the naturally aligned timestamp (8 bytes).
	*/
	struct {
	__be16 sample[2];
	s64 timestamp;
	} data ____cacheline_aligned;
	};

	static int ad7266_wakeup(struct ad7266_state *st)
	{
	/* Any read with >= 2 bytes will wake the device */
	return spi_read(st->spi, &st->data.sample[0], 2);
	}

	static int ad7266_powerdown(struct ad7266_state *st)
	{
	/* Any read with < 2 bytes will powerdown the device */
	return spi_read(st->spi, &st->data.sample[0], 1);
	}

	static int ad7266_preenable(struct iio_dev *indio_dev)
	{
	struct ad7266_state *st = iio_priv(indio_dev);
	return ad7266_wakeup(st);
	}

	static int ad7266_postdisable(struct iio_dev *indio_dev)
	{
	struct ad7266_state *st = iio_priv(indio_dev);
	return ad7266_powerdown(st);
	}

	static const struct iio_buffer_setup_ops iio_triggered_buffer_setup_ops = {
	.preenable = &ad7266_preenable,
	.postenable = &iio_triggered_buffer_postenable,
	.predisable = &iio_triggered_buffer_predisable,
	.postdisable = &ad7266_postdisable,
	};

	static irqreturn_t ad7266_trigger_handler(int irq, void *p)
	{
	struct iio_poll_func *pf = p;
	struct iio_dev *indio_dev = pf->indio_dev;
	struct ad7266_state *st = iio_priv(indio_dev);
	int ret;

	ret = spi_read(st->spi, st->data.sample, 4);
	if (ret == 0) {
	iio_push_to_buffers_with_timestamp(indio_dev, &st->data,
	pf->timestamp);
	}

	iio_trigger_notify_done(indio_dev->trig);

	return IRQ_HANDLED;
	}

	static void ad7266_select_input(struct ad7266_state *st, unsigned int nr)
	{
	unsigned int i;

	if (st->fixed_addr)
	return;

	switch (st->mode) {
	case AD7266_MODE_SINGLE_ENDED:
	nr >>= 1;
	break;
	case AD7266_MODE_PSEUDO_DIFF:
	nr \|= 1;
	break;
	case AD7266_MODE_DIFF:
	nr &= ~1;
	break;
	}

	for (i = 0; i < 3; ++i)
	gpiod_set_value(st->gpios[i], (bool)(nr & BIT(i)));
	}

	static int ad7266_update_scan_mode(struct iio_dev *indio_dev,
	const unsigned long *scan_mask)
	{
	struct ad7266_state *st = iio_priv(indio_dev);
	unsigned int nr = find_first_bit(scan_mask, indio_dev->masklength);

	ad7266_select_input(st, nr);

	return 0;
	}

	static int ad7266_read_single(struct ad7266_state st, int val,
	unsigned int address)
	{
	int ret;

	ad7266_select_input(st, address);

	ret = spi_sync(st->spi, &st->single_msg);
	*val = be16_to_cpu(st->data.sample[address % 2]);

	return ret;
	}

	static int ad7266_read_raw(struct iio_dev *indio_dev,
	struct iio_chan_spec const chan, int val, int *val2, long m)
	{
	struct ad7266_state *st = iio_priv(indio_dev);
	unsigned long scale_mv;
	int ret;

	switch (m) {
	case IIO_CHAN_INFO_RAW:
	ret = iio_device_claim_direct_mode(indio_dev);
	if (ret)
	return ret;
	ret = ad7266_read_single(st, val, chan->address);
	iio_device_release_direct_mode(indio_dev);

	val = (val >> 2) & 0xfff;
	if (chan->scan_type.sign == 's')
	val = sign_extend32(val, 11);

	return IIO_VAL_INT;
	case IIO_CHAN_INFO_SCALE:
	scale_mv = st->vref_mv;
	if (st->mode == AD7266_MODE_DIFF)
	scale_mv *= 2;
	if (st->range == AD7266_RANGE_2VREF)
	scale_mv *= 2;

	*val = scale_mv;
	*val2 = chan->scan_type.realbits;
	return IIO_VAL_FRACTIONAL_LOG2;
	case IIO_CHAN_INFO_OFFSET:
	if (st->range == AD7266_RANGE_2VREF &&
	st->mode != AD7266_MODE_DIFF)
	*val = 2048;
	else
	*val = 0;
	return IIO_VAL_INT;
	}
	return -EINVAL;
	}

	#define AD7266_CHAN(_chan, _sign) { \
	.type = IIO_VOLTAGE, \
	.indexed = 1, \
	.channel = (_chan), \
	.address = (_chan), \
	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \
	\| BIT(IIO_CHAN_INFO_OFFSET), \
	.scan_index = (_chan), \
	.scan_type = { \
	.sign = (_sign), \
	.realbits = 12, \
	.storagebits = 16, \
	.shift = 2, \
	.endianness = IIO_BE, \
	}, \
	}

	#define AD7266_DECLARE_SINGLE_ENDED_CHANNELS(_name, _sign) \
	const struct iio_chan_spec ad7266_channels_##_name[] = { \
	AD7266_CHAN(0, (_sign)), \
	AD7266_CHAN(1, (_sign)), \
	AD7266_CHAN(2, (_sign)), \
	AD7266_CHAN(3, (_sign)), \
	AD7266_CHAN(4, (_sign)), \
	AD7266_CHAN(5, (_sign)), \
	AD7266_CHAN(6, (_sign)), \
	AD7266_CHAN(7, (_sign)), \
	AD7266_CHAN(8, (_sign)), \
	AD7266_CHAN(9, (_sign)), \
	AD7266_CHAN(10, (_sign)), \
	AD7266_CHAN(11, (_sign)), \
	IIO_CHAN_SOFT_TIMESTAMP(13), \
	}

	#define AD7266_DECLARE_SINGLE_ENDED_CHANNELS_FIXED(_name, _sign) \
	const struct iio_chan_spec ad7266_channels_##_name##_fixed[] = { \
	AD7266_CHAN(0, (_sign)), \
	AD7266_CHAN(1, (_sign)), \
	IIO_CHAN_SOFT_TIMESTAMP(2), \
	}

	static AD7266_DECLARE_SINGLE_ENDED_CHANNELS(u, 'u');
	static AD7266_DECLARE_SINGLE_ENDED_CHANNELS(s, 's');
	static AD7266_DECLARE_SINGLE_ENDED_CHANNELS_FIXED(u, 'u');
	static AD7266_DECLARE_SINGLE_ENDED_CHANNELS_FIXED(s, 's');

	#define AD7266_CHAN_DIFF(_chan, _sign) { \
	.type = IIO_VOLTAGE, \
	.indexed = 1, \
	.channel = (_chan) * 2, \
	.channel2 = (_chan) * 2 + 1, \
	.address = (_chan), \
	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \
	\| BIT(IIO_CHAN_INFO_OFFSET), \
	.scan_index = (_chan), \
	.scan_type = { \
	.sign = _sign, \
	.realbits = 12, \
	.storagebits = 16, \
	.shift = 2, \
	.endianness = IIO_BE, \
	}, \
	.differential = 1, \
	}

	#define AD7266_DECLARE_DIFF_CHANNELS(_name, _sign) \
	const struct iio_chan_spec ad7266_channels_diff_##_name[] = { \
	AD7266_CHAN_DIFF(0, (_sign)), \
	AD7266_CHAN_DIFF(1, (_sign)), \
	AD7266_CHAN_DIFF(2, (_sign)), \
	AD7266_CHAN_DIFF(3, (_sign)), \
	AD7266_CHAN_DIFF(4, (_sign)), \
	AD7266_CHAN_DIFF(5, (_sign)), \
	IIO_CHAN_SOFT_TIMESTAMP(6), \
	}

	static AD7266_DECLARE_DIFF_CHANNELS(s, 's');
	static AD7266_DECLARE_DIFF_CHANNELS(u, 'u');

	#define AD7266_DECLARE_DIFF_CHANNELS_FIXED(_name, _sign) \
	const struct iio_chan_spec ad7266_channels_diff_fixed_##_name[] = { \
	AD7266_CHAN_DIFF(0, (_sign)), \
	AD7266_CHAN_DIFF(1, (_sign)), \
	IIO_CHAN_SOFT_TIMESTAMP(2), \
	}

	static AD7266_DECLARE_DIFF_CHANNELS_FIXED(s, 's');
	static AD7266_DECLARE_DIFF_CHANNELS_FIXED(u, 'u');

	static const struct iio_info ad7266_info = {
	.read_raw = &ad7266_read_raw,
	.update_scan_mode = &ad7266_update_scan_mode,
	};

	static const unsigned long ad7266_available_scan_masks[] = {
	0x003,
	0x00c,
	0x030,
	0x0c0,
	0x300,
	0xc00,
	0x000,
	};

	static const unsigned long ad7266_available_scan_masks_diff[] = {
	0x003,
	0x00c,
	0x030,
	0x000,
	};

	static const unsigned long ad7266_available_scan_masks_fixed[] = {
	0x003,
	0x000,
	};

	struct ad7266_chan_info {
	const struct iio_chan_spec *channels;
	unsigned int num_channels;
	const unsigned long *scan_masks;
	};

	#define AD7266_CHAN_INFO_INDEX(_differential, _signed, _fixed) \
	(((_differential) << 2) \| ((_signed) << 1) \| ((_fixed) << 0))

	static const struct ad7266_chan_info ad7266_chan_infos[] = {
	[AD7266_CHAN_INFO_INDEX(0, 0, 0)] = {
	.channels = ad7266_channels_u,
	.num_channels = ARRAY_SIZE(ad7266_channels_u),
	.scan_masks = ad7266_available_scan_masks,
	},
	[AD7266_CHAN_INFO_INDEX(0, 0, 1)] = {
	.channels = ad7266_channels_u_fixed,
	.num_channels = ARRAY_SIZE(ad7266_channels_u_fixed),
	.scan_masks = ad7266_available_scan_masks_fixed,
	},
	[AD7266_CHAN_INFO_INDEX(0, 1, 0)] = {
	.channels = ad7266_channels_s,
	.num_channels = ARRAY_SIZE(ad7266_channels_s),
	.scan_masks = ad7266_available_scan_masks,
	},
	[AD7266_CHAN_INFO_INDEX(0, 1, 1)] = {
	.channels = ad7266_channels_s_fixed,
	.num_channels = ARRAY_SIZE(ad7266_channels_s_fixed),
	.scan_masks = ad7266_available_scan_masks_fixed,
	},
	[AD7266_CHAN_INFO_INDEX(1, 0, 0)] = {
	.channels = ad7266_channels_diff_u,
	.num_channels = ARRAY_SIZE(ad7266_channels_diff_u),
	.scan_masks = ad7266_available_scan_masks_diff,
	},
	[AD7266_CHAN_INFO_INDEX(1, 0, 1)] = {
	.channels = ad7266_channels_diff_fixed_u,
	.num_channels = ARRAY_SIZE(ad7266_channels_diff_fixed_u),
	.scan_masks = ad7266_available_scan_masks_fixed,
	},
	[AD7266_CHAN_INFO_INDEX(1, 1, 0)] = {
	.channels = ad7266_channels_diff_s,
	.num_channels = ARRAY_SIZE(ad7266_channels_diff_s),
	.scan_masks = ad7266_available_scan_masks_diff,
	},
	[AD7266_CHAN_INFO_INDEX(1, 1, 1)] = {
	.channels = ad7266_channels_diff_fixed_s,
	.num_channels = ARRAY_SIZE(ad7266_channels_diff_fixed_s),
	.scan_masks = ad7266_available_scan_masks_fixed,
	},
	};

	static void ad7266_init_channels(struct iio_dev *indio_dev)
	{
	struct ad7266_state *st = iio_priv(indio_dev);
	bool is_differential, is_signed;
	const struct ad7266_chan_info *chan_info;
	int i;

	is_differential = st->mode != AD7266_MODE_SINGLE_ENDED;
	is_signed = (st->range == AD7266_RANGE_2VREF) \|
	(st->mode == AD7266_MODE_DIFF);

	i = AD7266_CHAN_INFO_INDEX(is_differential, is_signed, st->fixed_addr);
	chan_info = &ad7266_chan_infos[i];

	indio_dev->channels = chan_info->channels;
	indio_dev->num_channels = chan_info->num_channels;
	indio_dev->available_scan_masks = chan_info->scan_masks;
	indio_dev->masklength = chan_info->num_channels - 1;
	}

	static const char * const ad7266_gpio_labels[] = {
	"ad0", "ad1", "ad2",
	};

	static int ad7266_probe(struct spi_device *spi)
	{
	struct ad7266_platform_data *pdata = spi->dev.platform_data;
	struct iio_dev *indio_dev;
	struct ad7266_state *st;
	unsigned int i;
	int ret;

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

	st = iio_priv(indio_dev);

	st->reg = devm_regulator_get_optional(&spi->dev, "vref");
	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;

	st->vref_mv = ret / 1000;
	} else {
	/* Any other error indicates that the regulator does exist */
	if (PTR_ERR(st->reg) != -ENODEV)
	return PTR_ERR(st->reg);
	/* Use internal reference */
	st->vref_mv = 2500;
	}

	if (pdata) {
	st->fixed_addr = pdata->fixed_addr;
	st->mode = pdata->mode;
	st->range = pdata->range;

	if (!st->fixed_addr) {
	for (i = 0; i < ARRAY_SIZE(st->gpios); ++i) {
	st->gpios[i] = devm_gpiod_get(&spi->dev,
	ad7266_gpio_labels[i],
	GPIOD_OUT_LOW);
	if (IS_ERR(st->gpios[i])) {
	ret = PTR_ERR(st->gpios[i]);
	goto error_disable_reg;
	}
	}
	}
	} else {
	st->fixed_addr = true;
	st->range = AD7266_RANGE_VREF;
	st->mode = AD7266_MODE_DIFF;
	}

	spi_set_drvdata(spi, indio_dev);
	st->spi = spi;

	indio_dev->dev.parent = &spi->dev;
	indio_dev->dev.of_node = spi->dev.of_node;
	indio_dev->name = spi_get_device_id(spi)->name;
	indio_dev->modes = INDIO_DIRECT_MODE;
	indio_dev->info = &ad7266_info;

	ad7266_init_channels(indio_dev);

	/* wakeup */
	st->single_xfer[0].rx_buf = &st->data.sample[0];
	st->single_xfer[0].len = 2;
	st->single_xfer[0].cs_change = 1;
	/* conversion */
	st->single_xfer[1].rx_buf = st->data.sample;
	st->single_xfer[1].len = 4;
	st->single_xfer[1].cs_change = 1;
	/* powerdown */
	st->single_xfer[2].tx_buf = &st->data.sample[0];
	st->single_xfer[2].len = 1;

	spi_message_init(&st->single_msg);
	spi_message_add_tail(&st->single_xfer[0], &st->single_msg);
	spi_message_add_tail(&st->single_xfer[1], &st->single_msg);
	spi_message_add_tail(&st->single_xfer[2], &st->single_msg);

	ret = iio_triggered_buffer_setup(indio_dev, &iio_pollfunc_store_time,
	&ad7266_trigger_handler, &iio_triggered_buffer_setup_ops);
	if (ret)
	goto error_disable_reg;

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

	return 0;

	error_buffer_cleanup:
	iio_triggered_buffer_cleanup(indio_dev);
	error_disable_reg:
	if (!IS_ERR(st->reg))
	regulator_disable(st->reg);

	return ret;
	}

	static int ad7266_remove(struct spi_device *spi)
	{
	struct iio_dev *indio_dev = spi_get_drvdata(spi);
	struct ad7266_state *st = iio_priv(indio_dev);

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

	return 0;
	}

	static const struct spi_device_id ad7266_id[] = {
	{"ad7265", 0},
	{"ad7266", 0},
	{ }
	};
	MODULE_DEVICE_TABLE(spi, ad7266_id);

	static struct spi_driver ad7266_driver = {
	.driver = {
	.name = "ad7266",
	},
	.probe = ad7266_probe,
	.remove = ad7266_remove,
	.id_table = ad7266_id,
	};
	module_spi_driver(ad7266_driver);

	MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
	MODULE_DESCRIPTION("Analog Devices AD7266/65 ADC");
	MODULE_LICENSE("GPL v2");