[linux-block.git] / drivers / iio / adc / ad_sigma_delta.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Support code for Analog Devices Sigma-Delta ADCs
 *
 * Copyright 2012 Analog Devices Inc.
 *  Author: Lars-Peter Clausen <lars@metafoo.de>
 */

#include <linux/align.h>
#include <linux/interrupt.h>
#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/spi/spi.h>
#include <linux/err.h>
#include <linux/module.h>

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

#include <asm/unaligned.h>


#define AD_SD_COMM_CHAN_MASK	0x3

#define AD_SD_REG_COMM		0x00
#define AD_SD_REG_DATA		0x03

/**
 * ad_sd_set_comm() - Set communications register
 *
 * @sigma_delta: The sigma delta device
 * @comm: New value for the communications register
 */
void ad_sd_set_comm(struct ad_sigma_delta *sigma_delta, uint8_t comm)
{
	/* Some variants use the lower two bits of the communications register
	 * to select the channel */
	sigma_delta->comm = comm & AD_SD_COMM_CHAN_MASK;
}
EXPORT_SYMBOL_NS_GPL(ad_sd_set_comm, IIO_AD_SIGMA_DELTA);

/**
 * ad_sd_write_reg() - Write a register
 *
 * @sigma_delta: The sigma delta device
 * @reg: Address of the register
 * @size: Size of the register (0-3)
 * @val: Value to write to the register
 *
 * Returns 0 on success, an error code otherwise.
 **/
int ad_sd_write_reg(struct ad_sigma_delta *sigma_delta, unsigned int reg,
	unsigned int size, unsigned int val)
{
	uint8_t *data = sigma_delta->tx_buf;
	struct spi_transfer t = {
		.tx_buf		= data,
		.len		= size + 1,
		.cs_change	= sigma_delta->keep_cs_asserted,
	};
	struct spi_message m;
	int ret;

	data[0] = (reg << sigma_delta->info->addr_shift) | sigma_delta->comm;

	switch (size) {
	case 3:
		put_unaligned_be24(val, &data[1]);
		break;
	case 2:
		put_unaligned_be16(val, &data[1]);
		break;
	case 1:
		data[1] = val;
		break;
	case 0:
		break;
	default:
		return -EINVAL;
	}

	spi_message_init(&m);
	spi_message_add_tail(&t, &m);

	if (sigma_delta->bus_locked)
		ret = spi_sync_locked(sigma_delta->spi, &m);
	else
		ret = spi_sync(sigma_delta->spi, &m);

	return ret;
}
EXPORT_SYMBOL_NS_GPL(ad_sd_write_reg, IIO_AD_SIGMA_DELTA);

static int ad_sd_read_reg_raw(struct ad_sigma_delta *sigma_delta,
	unsigned int reg, unsigned int size, uint8_t *val)
{
	uint8_t *data = sigma_delta->tx_buf;
	int ret;
	struct spi_transfer t[] = {
		{
			.tx_buf = data,
			.len = 1,
		}, {
			.rx_buf = val,
			.len = size,
			.cs_change = sigma_delta->bus_locked,
		},
	};
	struct spi_message m;

	spi_message_init(&m);

	if (sigma_delta->info->has_registers) {
		data[0] = reg << sigma_delta->info->addr_shift;
		data[0] |= sigma_delta->info->read_mask;
		data[0] |= sigma_delta->comm;
		spi_message_add_tail(&t[0], &m);
	}
	spi_message_add_tail(&t[1], &m);

	if (sigma_delta->bus_locked)
		ret = spi_sync_locked(sigma_delta->spi, &m);
	else
		ret = spi_sync(sigma_delta->spi, &m);

	return ret;
}

/**
 * ad_sd_read_reg() - Read a register
 *
 * @sigma_delta: The sigma delta device
 * @reg: Address of the register
 * @size: Size of the register (1-4)
 * @val: Read value
 *
 * Returns 0 on success, an error code otherwise.
 **/
int ad_sd_read_reg(struct ad_sigma_delta *sigma_delta,
	unsigned int reg, unsigned int size, unsigned int *val)
{
	int ret;

	ret = ad_sd_read_reg_raw(sigma_delta, reg, size, sigma_delta->rx_buf);
	if (ret < 0)
		goto out;

	switch (size) {
	case 4:
		*val = get_unaligned_be32(sigma_delta->rx_buf);
		break;
	case 3:
		*val = get_unaligned_be24(sigma_delta->rx_buf);
		break;
	case 2:
		*val = get_unaligned_be16(sigma_delta->rx_buf);
		break;
	case 1:
		*val = sigma_delta->rx_buf[0];
		break;
	default:
		ret = -EINVAL;
		break;
	}

out:
	return ret;
}
EXPORT_SYMBOL_NS_GPL(ad_sd_read_reg, IIO_AD_SIGMA_DELTA);

/**
 * ad_sd_reset() - Reset the serial interface
 *
 * @sigma_delta: The sigma delta device
 * @reset_length: Number of SCLKs with DIN = 1
 *
 * Returns 0 on success, an error code otherwise.
 **/
int ad_sd_reset(struct ad_sigma_delta *sigma_delta,
	unsigned int reset_length)
{
	uint8_t *buf;
	unsigned int size;
	int ret;

	size = DIV_ROUND_UP(reset_length, 8);
	buf = kcalloc(size, sizeof(*buf), GFP_KERNEL);
	if (!buf)
		return -ENOMEM;

	memset(buf, 0xff, size);
	ret = spi_write(sigma_delta->spi, buf, size);
	kfree(buf);

	return ret;
}
EXPORT_SYMBOL_NS_GPL(ad_sd_reset, IIO_AD_SIGMA_DELTA);

int ad_sd_calibrate(struct ad_sigma_delta *sigma_delta,
	unsigned int mode, unsigned int channel)
{
	int ret;
	unsigned long timeout;

	ret = ad_sigma_delta_set_channel(sigma_delta, channel);
	if (ret)
		return ret;

	spi_bus_lock(sigma_delta->spi->master);
	sigma_delta->bus_locked = true;
	sigma_delta->keep_cs_asserted = true;
	reinit_completion(&sigma_delta->completion);

	ret = ad_sigma_delta_set_mode(sigma_delta, mode);
	if (ret < 0)
		goto out;

	sigma_delta->irq_dis = false;
	enable_irq(sigma_delta->spi->irq);
	timeout = wait_for_completion_timeout(&sigma_delta->completion, 2 * HZ);
	if (timeout == 0) {
		sigma_delta->irq_dis = true;
		disable_irq_nosync(sigma_delta->spi->irq);
		ret = -EIO;
	} else {
		ret = 0;
	}
out:
	sigma_delta->keep_cs_asserted = false;
	ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_IDLE);
	sigma_delta->bus_locked = false;
	spi_bus_unlock(sigma_delta->spi->master);

	return ret;
}
EXPORT_SYMBOL_NS_GPL(ad_sd_calibrate, IIO_AD_SIGMA_DELTA);

/**
 * ad_sd_calibrate_all() - Performs channel calibration
 * @sigma_delta: The sigma delta device
 * @cb: Array of channels and calibration type to perform
 * @n: Number of items in cb
 *
 * Returns 0 on success, an error code otherwise.
 **/
int ad_sd_calibrate_all(struct ad_sigma_delta *sigma_delta,
	const struct ad_sd_calib_data *cb, unsigned int n)
{
	unsigned int i;
	int ret;

	for (i = 0; i < n; i++) {
		ret = ad_sd_calibrate(sigma_delta, cb[i].mode, cb[i].channel);
		if (ret)
			return ret;
	}

	return 0;
}
EXPORT_SYMBOL_NS_GPL(ad_sd_calibrate_all, IIO_AD_SIGMA_DELTA);

/**
 * ad_sigma_delta_single_conversion() - Performs a single data conversion
 * @indio_dev: The IIO device
 * @chan: The conversion is done for this channel
 * @val: Pointer to the location where to store the read value
 *
 * Returns: 0 on success, an error value otherwise.
 */
int ad_sigma_delta_single_conversion(struct iio_dev *indio_dev,
	const struct iio_chan_spec *chan, int *val)
{
	struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
	unsigned int sample, raw_sample;
	unsigned int data_reg;
	int ret = 0;

	ret = iio_device_claim_direct_mode(indio_dev);
	if (ret)
		return ret;

	ad_sigma_delta_set_channel(sigma_delta, chan->address);

	spi_bus_lock(sigma_delta->spi->master);
	sigma_delta->bus_locked = true;
	sigma_delta->keep_cs_asserted = true;
	reinit_completion(&sigma_delta->completion);

	ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_SINGLE);

	sigma_delta->irq_dis = false;
	enable_irq(sigma_delta->spi->irq);
	ret = wait_for_completion_interruptible_timeout(
			&sigma_delta->completion, HZ);

	if (ret == 0)
		ret = -EIO;
	if (ret < 0)
		goto out;

	if (sigma_delta->info->data_reg != 0)
		data_reg = sigma_delta->info->data_reg;
	else
		data_reg = AD_SD_REG_DATA;

	ret = ad_sd_read_reg(sigma_delta, data_reg,
		DIV_ROUND_UP(chan->scan_type.realbits + chan->scan_type.shift, 8),
		&raw_sample);

out:
	if (!sigma_delta->irq_dis) {
		disable_irq_nosync(sigma_delta->spi->irq);
		sigma_delta->irq_dis = true;
	}

	sigma_delta->keep_cs_asserted = false;
	ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_IDLE);
	sigma_delta->bus_locked = false;
	spi_bus_unlock(sigma_delta->spi->master);
	iio_device_release_direct_mode(indio_dev);

	if (ret)
		return ret;

	sample = raw_sample >> chan->scan_type.shift;
	sample &= (1 << chan->scan_type.realbits) - 1;
	*val = sample;

	ret = ad_sigma_delta_postprocess_sample(sigma_delta, raw_sample);
	if (ret)
		return ret;

	return IIO_VAL_INT;
}
EXPORT_SYMBOL_NS_GPL(ad_sigma_delta_single_conversion, IIO_AD_SIGMA_DELTA);

static int ad_sd_buffer_postenable(struct iio_dev *indio_dev)
{
	struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
	unsigned int i, slot, samples_buf_size;
	unsigned int channel;
	uint8_t *samples_buf;
	int ret;

	if (sigma_delta->num_slots == 1) {
		channel = find_first_bit(indio_dev->active_scan_mask,
					 indio_dev->masklength);
		ret = ad_sigma_delta_set_channel(sigma_delta,
						 indio_dev->channels[channel].address);
		if (ret)
			return ret;
		slot = 1;
	} else {
		/*
		 * At this point update_scan_mode already enabled the required channels.
		 * For sigma-delta sequencer drivers with multiple slots, an update_scan_mode
		 * implementation is mandatory.
		 */
		slot = 0;
		for_each_set_bit(i, indio_dev->active_scan_mask, indio_dev->masklength) {
			sigma_delta->slots[slot] = indio_dev->channels[i].address;
			slot++;
		}
	}

	sigma_delta->active_slots = slot;
	sigma_delta->current_slot = 0;

	if (sigma_delta->active_slots > 1) {
		ret = ad_sigma_delta_append_status(sigma_delta, true);
		if (ret)
			return ret;
	}

	samples_buf_size = ALIGN(slot * indio_dev->channels[0].scan_type.storagebits, 8);
	samples_buf_size += sizeof(int64_t);
	samples_buf = devm_krealloc(&sigma_delta->spi->dev, sigma_delta->samples_buf,
				    samples_buf_size, GFP_KERNEL);
	if (!samples_buf)
		return -ENOMEM;

	sigma_delta->samples_buf = samples_buf;

	spi_bus_lock(sigma_delta->spi->master);
	sigma_delta->bus_locked = true;
	sigma_delta->keep_cs_asserted = true;

	ret = ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_CONTINUOUS);
	if (ret)
		goto err_unlock;

	sigma_delta->irq_dis = false;
	enable_irq(sigma_delta->spi->irq);

	return 0;

err_unlock:
	spi_bus_unlock(sigma_delta->spi->master);

	return ret;
}

static int ad_sd_buffer_postdisable(struct iio_dev *indio_dev)
{
	struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);

	reinit_completion(&sigma_delta->completion);
	wait_for_completion_timeout(&sigma_delta->completion, HZ);

	if (!sigma_delta->irq_dis) {
		disable_irq_nosync(sigma_delta->spi->irq);
		sigma_delta->irq_dis = true;
	}

	sigma_delta->keep_cs_asserted = false;
	ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_IDLE);

	if (sigma_delta->status_appended)
		ad_sigma_delta_append_status(sigma_delta, false);

	ad_sigma_delta_disable_all(sigma_delta);
	sigma_delta->bus_locked = false;
	return spi_bus_unlock(sigma_delta->spi->master);
}

static irqreturn_t ad_sd_trigger_handler(int irq, void *p)
{
	struct iio_poll_func *pf = p;
	struct iio_dev *indio_dev = pf->indio_dev;
	struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
	uint8_t *data = sigma_delta->rx_buf;
	unsigned int transfer_size;
	unsigned int sample_size;
	unsigned int sample_pos;
	unsigned int status_pos;
	unsigned int reg_size;
	unsigned int data_reg;

	reg_size = indio_dev->channels[0].scan_type.realbits +
			indio_dev->channels[0].scan_type.shift;
	reg_size = DIV_ROUND_UP(reg_size, 8);

	if (sigma_delta->info->data_reg != 0)
		data_reg = sigma_delta->info->data_reg;
	else
		data_reg = AD_SD_REG_DATA;

	/* Status word will be appended to the sample during transfer */
	if (sigma_delta->status_appended)
		transfer_size = reg_size + 1;
	else
		transfer_size = reg_size;

	switch (reg_size) {
	case 4:
	case 2:
	case 1:
		status_pos = reg_size;
		ad_sd_read_reg_raw(sigma_delta, data_reg, transfer_size, &data[0]);
		break;
	case 3:
		/*
		 * Data array after transfer will look like (if status is appended):
		 * data[] = { [0][sample][sample][sample][status] }
		 * Keeping the first byte 0 shifts the status postion by 1 byte to the right.
		 */
		status_pos = reg_size + 1;

		/* We store 24 bit samples in a 32 bit word. Keep the upper
		 * byte set to zero. */
		ad_sd_read_reg_raw(sigma_delta, data_reg, transfer_size, &data[1]);
		break;
	}

	/*
	 * For devices sampling only one channel at
	 * once, there is no need for sample number tracking.
	 */
	if (sigma_delta->active_slots == 1) {
		iio_push_to_buffers_with_timestamp(indio_dev, data, pf->timestamp);
		goto irq_handled;
	}

	if (sigma_delta->status_appended) {
		u8 converted_channel;

		converted_channel = data[status_pos] & sigma_delta->info->status_ch_mask;
		if (converted_channel != sigma_delta->slots[sigma_delta->current_slot]) {
			/*
			 * Desync occurred during continuous sampling of multiple channels.
			 * Drop this incomplete sample and start from first channel again.
			 */

			sigma_delta->current_slot = 0;
			goto irq_handled;
		}
	}

	sample_size = indio_dev->channels[0].scan_type.storagebits / 8;
	sample_pos = sample_size * sigma_delta->current_slot;
	memcpy(&sigma_delta->samples_buf[sample_pos], data, sample_size);
	sigma_delta->current_slot++;

	if (sigma_delta->current_slot == sigma_delta->active_slots) {
		sigma_delta->current_slot = 0;
		iio_push_to_buffers_with_timestamp(indio_dev, sigma_delta->samples_buf,
						   pf->timestamp);
	}

irq_handled:
	iio_trigger_notify_done(indio_dev->trig);
	sigma_delta->irq_dis = false;
	enable_irq(sigma_delta->spi->irq);

	return IRQ_HANDLED;
}

static bool ad_sd_validate_scan_mask(struct iio_dev *indio_dev, const unsigned long *mask)
{
	struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);

	return bitmap_weight(mask, indio_dev->masklength) <= sigma_delta->num_slots;
}

static const struct iio_buffer_setup_ops ad_sd_buffer_setup_ops = {
	.postenable = &ad_sd_buffer_postenable,
	.postdisable = &ad_sd_buffer_postdisable,
	.validate_scan_mask = &ad_sd_validate_scan_mask,
};

static irqreturn_t ad_sd_data_rdy_trig_poll(int irq, void *private)
{
	struct ad_sigma_delta *sigma_delta = private;

	complete(&sigma_delta->completion);
	disable_irq_nosync(irq);
	sigma_delta->irq_dis = true;
	iio_trigger_poll(sigma_delta->trig);

	return IRQ_HANDLED;
}

/**
 * ad_sd_validate_trigger() - validate_trigger callback for ad_sigma_delta devices
 * @indio_dev: The IIO device
 * @trig: The new trigger
 *
 * Returns: 0 if the 'trig' matches the trigger registered by the ad_sigma_delta
 * device, -EINVAL otherwise.
 */
int ad_sd_validate_trigger(struct iio_dev *indio_dev, struct iio_trigger *trig)
{
	struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);

	if (sigma_delta->trig != trig)
		return -EINVAL;

	return 0;
}
EXPORT_SYMBOL_NS_GPL(ad_sd_validate_trigger, IIO_AD_SIGMA_DELTA);

static int devm_ad_sd_probe_trigger(struct device *dev, struct iio_dev *indio_dev)
{
	struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
	int ret;

	if (dev != &sigma_delta->spi->dev) {
		dev_err(dev, "Trigger parent should be '%s', got '%s'\n",
			dev_name(dev), dev_name(&sigma_delta->spi->dev));
		return -EFAULT;
	}

	sigma_delta->trig = devm_iio_trigger_alloc(dev, "%s-dev%d", indio_dev->name,
						   iio_device_id(indio_dev));
	if (sigma_delta->trig == NULL)
		return -ENOMEM;

	init_completion(&sigma_delta->completion);

	sigma_delta->irq_dis = true;
	ret = devm_request_irq(dev, sigma_delta->spi->irq,
			       ad_sd_data_rdy_trig_poll,
			       sigma_delta->info->irq_flags | IRQF_NO_AUTOEN,
			       indio_dev->name,
			       sigma_delta);
	if (ret)
		return ret;

	iio_trigger_set_drvdata(sigma_delta->trig, sigma_delta);

	ret = devm_iio_trigger_register(dev, sigma_delta->trig);
	if (ret)
		return ret;

	/* select default trigger */
	indio_dev->trig = iio_trigger_get(sigma_delta->trig);

	return 0;
}

/**
 * devm_ad_sd_setup_buffer_and_trigger() - Device-managed buffer & trigger setup
 * @dev: Device object to which to bind the life-time of the resources attached
 * @indio_dev: The IIO device
 */
int devm_ad_sd_setup_buffer_and_trigger(struct device *dev, struct iio_dev *indio_dev)
{
	struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
	int ret;

	sigma_delta->slots = devm_kcalloc(dev, sigma_delta->num_slots,
					  sizeof(*sigma_delta->slots), GFP_KERNEL);
	if (!sigma_delta->slots)
		return -ENOMEM;

	ret = devm_iio_triggered_buffer_setup(dev, indio_dev,
					      &iio_pollfunc_store_time,
					      &ad_sd_trigger_handler,
					      &ad_sd_buffer_setup_ops);
	if (ret)
		return ret;

	return devm_ad_sd_probe_trigger(dev, indio_dev);
}
EXPORT_SYMBOL_NS_GPL(devm_ad_sd_setup_buffer_and_trigger, IIO_AD_SIGMA_DELTA);

/**
 * ad_sd_init() - Initializes a ad_sigma_delta struct
 * @sigma_delta: The ad_sigma_delta device
 * @indio_dev: The IIO device which the Sigma Delta device is used for
 * @spi: The SPI device for the ad_sigma_delta device
 * @info: Device specific callbacks and options
 *
 * This function needs to be called before any other operations are performed on
 * the ad_sigma_delta struct.
 */
int ad_sd_init(struct ad_sigma_delta *sigma_delta, struct iio_dev *indio_dev,
	struct spi_device *spi, const struct ad_sigma_delta_info *info)
{
	sigma_delta->spi = spi;
	sigma_delta->info = info;

	/* If the field is unset in ad_sigma_delta_info, asume there can only be 1 slot. */
	if (!info->num_slots)
		sigma_delta->num_slots = 1;
	else
		sigma_delta->num_slots = info->num_slots;

	if (sigma_delta->num_slots > 1) {
		if (!indio_dev->info->update_scan_mode) {
			dev_err(&spi->dev, "iio_dev lacks update_scan_mode().\n");
			return -EINVAL;
		}

		if (!info->disable_all) {
			dev_err(&spi->dev, "ad_sigma_delta_info lacks disable_all().\n");
			return -EINVAL;
		}
	}

	iio_device_set_drvdata(indio_dev, sigma_delta);

	return 0;
}
EXPORT_SYMBOL_NS_GPL(ad_sd_init, IIO_AD_SIGMA_DELTA);

MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
MODULE_DESCRIPTION("Analog Devices Sigma-Delta ADCs");
MODULE_LICENSE("GPL v2");
Commit	Line	Data
fda8d26e	1	// SPDX-License-Identifier: GPL-2.0-only
af300848 LPC	2	/*
	3	* Support code for Analog Devices Sigma-Delta ADCs
	4	*
	5	* Copyright 2012 Analog Devices Inc.
	6	* Author: Lars-Peter Clausen <lars@metafoo.de>
af300848 LPC	7	*/
af300848 LPC	8
8bea9af8	9	#include <linux/align.h>
af300848 LPC	10	#include <linux/interrupt.h>
	11	#include <linux/device.h>
	12	#include <linux/kernel.h>
	13	#include <linux/slab.h>
	14	#include <linux/spi/spi.h>
	15	#include <linux/err.h>
	16	#include <linux/module.h>
	17
	18	#include <linux/iio/iio.h>
	19	#include <linux/iio/sysfs.h>
	20	#include <linux/iio/buffer.h>
	21	#include <linux/iio/trigger.h>
	22	#include <linux/iio/trigger_consumer.h>
	23	#include <linux/iio/triggered_buffer.h>
	24	#include <linux/iio/adc/ad_sigma_delta.h>
	25
	26	#include <asm/unaligned.h>
	27
	28
	29	#define AD_SD_COMM_CHAN_MASK 0x3
	30
	31	#define AD_SD_REG_COMM 0x00
	32	#define AD_SD_REG_DATA 0x03
	33
	34	/**
	35	* ad_sd_set_comm() - Set communications register
	36	*
	37	* @sigma_delta: The sigma delta device
	38	* @comm: New value for the communications register
	39	*/
	40	void ad_sd_set_comm(struct ad_sigma_delta *sigma_delta, uint8_t comm)
	41	{
	42	/* Some variants use the lower two bits of the communications register
	43	* to select the channel */
	44	sigma_delta->comm = comm & AD_SD_COMM_CHAN_MASK;
	45	}
ef807729	46	EXPORT_SYMBOL_NS_GPL(ad_sd_set_comm, IIO_AD_SIGMA_DELTA);
af300848 LPC	47
	48	/**
	49	* ad_sd_write_reg() - Write a register
	50	*
	51	* @sigma_delta: The sigma delta device
	52	* @reg: Address of the register
	53	* @size: Size of the register (0-3)
	54	* @val: Value to write to the register
	55	*
	56	* Returns 0 on success, an error code otherwise.
	57	**/
	58	int ad_sd_write_reg(struct ad_sigma_delta *sigma_delta, unsigned int reg,
	59	unsigned int size, unsigned int val)
	60	{
0fb6ee8d	61	uint8_t *data = sigma_delta->tx_buf;
af300848 LPC	62	struct spi_transfer t = {
	63	.tx_buf = data,
	64	.len = size + 1,
df1d80ae	65	.cs_change = sigma_delta->keep_cs_asserted,
af300848 LPC	66	};
	67	struct spi_message m;
	68	int ret;
	69
	70	data[0] = (reg << sigma_delta->info->addr_shift) \| sigma_delta->comm;
	71
	72	switch (size) {
	73	case 3:
c1909ab0	74	put_unaligned_be24(val, &data[1]);
af300848 LPC	75	break;
	76	case 2:
	77	put_unaligned_be16(val, &data[1]);
	78	break;
	79	case 1:
	80	data[1] = val;
	81	break;
	82	case 0:
	83	break;
	84	default:
	85	return -EINVAL;
	86	}
	87
	88	spi_message_init(&m);
	89	spi_message_add_tail(&t, &m);
	90
	91	if (sigma_delta->bus_locked)
	92	ret = spi_sync_locked(sigma_delta->spi, &m);
	93	else
	94	ret = spi_sync(sigma_delta->spi, &m);
	95
	96	return ret;
	97	}
ef807729	98	EXPORT_SYMBOL_NS_GPL(ad_sd_write_reg, IIO_AD_SIGMA_DELTA);
af300848 LPC	99
	100	static int ad_sd_read_reg_raw(struct ad_sigma_delta *sigma_delta,
	101	unsigned int reg, unsigned int size, uint8_t *val)
	102	{
0fb6ee8d	103	uint8_t *data = sigma_delta->tx_buf;
af300848 LPC	104	int ret;
	105	struct spi_transfer t[] = {
	106	{
	107	.tx_buf = data,
	108	.len = 1,
	109	}, {
	110	.rx_buf = val,
	111	.len = size,
	112	.cs_change = sigma_delta->bus_locked,
	113	},
	114	};
	115	struct spi_message m;
	116
	117	spi_message_init(&m);
	118
	119	if (sigma_delta->info->has_registers) {
	120	data[0] = reg << sigma_delta->info->addr_shift;
	121	data[0] \|= sigma_delta->info->read_mask;
fccfb9ce	122	data[0] \|= sigma_delta->comm;
af300848 LPC	123	spi_message_add_tail(&t[0], &m);
	124	}
	125	spi_message_add_tail(&t[1], &m);
	126
	127	if (sigma_delta->bus_locked)
	128	ret = spi_sync_locked(sigma_delta->spi, &m);
	129	else
	130	ret = spi_sync(sigma_delta->spi, &m);
	131
	132	return ret;
	133	}
	134
	135	/**
	136	* ad_sd_read_reg() - Read a register
	137	*
	138	* @sigma_delta: The sigma delta device
	139	* @reg: Address of the register
	140	* @size: Size of the register (1-4)
	141	* @val: Read value
	142	*
	143	* Returns 0 on success, an error code otherwise.
	144	**/
	145	int ad_sd_read_reg(struct ad_sigma_delta *sigma_delta,
	146	unsigned int reg, unsigned int size, unsigned int *val)
	147	{
	148	int ret;
	149
0fb6ee8d	150	ret = ad_sd_read_reg_raw(sigma_delta, reg, size, sigma_delta->rx_buf);
af300848 LPC	151	if (ret < 0)
	152	goto out;
	153
	154	switch (size) {
	155	case 4:
0fb6ee8d	156	*val = get_unaligned_be32(sigma_delta->rx_buf);
af300848 LPC	157	break;
af300848 LPC	158	case 3:
0fb6ee8d	159	*val = get_unaligned_be24(sigma_delta->rx_buf);
af300848 LPC	160	break;
af300848 LPC	161	case 2:
0fb6ee8d	162	*val = get_unaligned_be16(sigma_delta->rx_buf);
af300848 LPC	163	break;
af300848 LPC	164	case 1:
0fb6ee8d	165	*val = sigma_delta->rx_buf[0];
af300848 LPC	166	break;
	167	default:
	168	ret = -EINVAL;
	169	break;
	170	}
	171
	172	out:
	173	return ret;
	174	}
ef807729	175	EXPORT_SYMBOL_NS_GPL(ad_sd_read_reg, IIO_AD_SIGMA_DELTA);
af300848	176
7fc10de8 DB	177	/**
	178	* ad_sd_reset() - Reset the serial interface
	179	*
	180	* @sigma_delta: The sigma delta device
	181	* @reset_length: Number of SCLKs with DIN = 1
	182	*
	183	* Returns 0 on success, an error code otherwise.
	184	**/
	185	int ad_sd_reset(struct ad_sigma_delta *sigma_delta,
	186	unsigned int reset_length)
	187	{
	188	uint8_t *buf;
	189	unsigned int size;
	190	int ret;
	191
	192	size = DIV_ROUND_UP(reset_length, 8);
	193	buf = kcalloc(size, sizeof(*buf), GFP_KERNEL);
	194	if (!buf)
	195	return -ENOMEM;
	196
	197	memset(buf, 0xff, size);
	198	ret = spi_write(sigma_delta->spi, buf, size);
	199	kfree(buf);
	200
	201	return ret;
	202	}
ef807729	203	EXPORT_SYMBOL_NS_GPL(ad_sd_reset, IIO_AD_SIGMA_DELTA);
7fc10de8	204
c88c8cd8	205	int ad_sd_calibrate(struct ad_sigma_delta *sigma_delta,
af300848 LPC	206	unsigned int mode, unsigned int channel)
	207	{
	208	int ret;
cebc4585	209	unsigned long timeout;
af300848 LPC	210
	211	ret = ad_sigma_delta_set_channel(sigma_delta, channel);
	212	if (ret)
	213	return ret;
	214
	215	spi_bus_lock(sigma_delta->spi->master);
	216	sigma_delta->bus_locked = true;
df1d80ae	217	sigma_delta->keep_cs_asserted = true;
16735d02	218	reinit_completion(&sigma_delta->completion);
af300848 LPC	219
	220	ret = ad_sigma_delta_set_mode(sigma_delta, mode);
	221	if (ret < 0)
	222	goto out;
	223
	224	sigma_delta->irq_dis = false;
	225	enable_irq(sigma_delta->spi->irq);
cebc4585 NMG	226	timeout = wait_for_completion_timeout(&sigma_delta->completion, 2 * HZ);
cebc4585 NMG	227	if (timeout == 0) {
af300848 LPC	228	sigma_delta->irq_dis = true;
	229	disable_irq_nosync(sigma_delta->spi->irq);
	230	ret = -EIO;
	231	} else {
	232	ret = 0;
	233	}
	234	out:
df1d80ae LPC	235	sigma_delta->keep_cs_asserted = false;
df1d80ae LPC	236	ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_IDLE);
af300848 LPC	237	sigma_delta->bus_locked = false;
af300848 LPC	238	spi_bus_unlock(sigma_delta->spi->master);
af300848 LPC	239
	240	return ret;
	241	}
ef807729	242	EXPORT_SYMBOL_NS_GPL(ad_sd_calibrate, IIO_AD_SIGMA_DELTA);
af300848 LPC	243
	244	/**
	245	* ad_sd_calibrate_all() - Performs channel calibration
	246	* @sigma_delta: The sigma delta device
	247	* @cb: Array of channels and calibration type to perform
	248	* @n: Number of items in cb
	249	*
	250	* Returns 0 on success, an error code otherwise.
	251	**/
	252	int ad_sd_calibrate_all(struct ad_sigma_delta *sigma_delta,
	253	const struct ad_sd_calib_data *cb, unsigned int n)
	254	{
	255	unsigned int i;
	256	int ret;
	257
	258	for (i = 0; i < n; i++) {
	259	ret = ad_sd_calibrate(sigma_delta, cb[i].mode, cb[i].channel);
	260	if (ret)
	261	return ret;
	262	}
	263
	264	return 0;
	265	}
ef807729	266	EXPORT_SYMBOL_NS_GPL(ad_sd_calibrate_all, IIO_AD_SIGMA_DELTA);
af300848 LPC	267
	268	/**
	269	* ad_sigma_delta_single_conversion() - Performs a single data conversion
	270	* @indio_dev: The IIO device
	271	* @chan: The conversion is done for this channel
	272	* @val: Pointer to the location where to store the read value
	273	*
	274	* Returns: 0 on success, an error value otherwise.
	275	*/
	276	int ad_sigma_delta_single_conversion(struct iio_dev *indio_dev,
	277	const struct iio_chan_spec chan, int val)
	278	{
	279	struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
	280	unsigned int sample, raw_sample;
f0aef2d0	281	unsigned int data_reg;
af300848 LPC	282	int ret = 0;
af300848 LPC	283
20228a1d NS	284	ret = iio_device_claim_direct_mode(indio_dev);
	285	if (ret)
	286	return ret;
af300848	287
af300848 LPC	288	ad_sigma_delta_set_channel(sigma_delta, chan->address);
	289
	290	spi_bus_lock(sigma_delta->spi->master);
	291	sigma_delta->bus_locked = true;
df1d80ae	292	sigma_delta->keep_cs_asserted = true;
16735d02	293	reinit_completion(&sigma_delta->completion);
af300848 LPC	294
	295	ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_SINGLE);
	296
	297	sigma_delta->irq_dis = false;
	298	enable_irq(sigma_delta->spi->irq);
	299	ret = wait_for_completion_interruptible_timeout(
	300	&sigma_delta->completion, HZ);
	301
af300848 LPC	302	if (ret == 0)
	303	ret = -EIO;
	304	if (ret < 0)
	305	goto out;
	306
f0aef2d0 LPC	307	if (sigma_delta->info->data_reg != 0)
	308	data_reg = sigma_delta->info->data_reg;
	309	else
	310	data_reg = AD_SD_REG_DATA;
	311
	312	ret = ad_sd_read_reg(sigma_delta, data_reg,
af300848 LPC	313	DIV_ROUND_UP(chan->scan_type.realbits + chan->scan_type.shift, 8),
	314	&raw_sample);
	315
	316	out:
	317	if (!sigma_delta->irq_dis) {
	318	disable_irq_nosync(sigma_delta->spi->irq);
	319	sigma_delta->irq_dis = true;
	320	}
	321
df1d80ae	322	sigma_delta->keep_cs_asserted = false;
af300848	323	ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_IDLE);
df1d80ae LPC	324	sigma_delta->bus_locked = false;
df1d80ae LPC	325	spi_bus_unlock(sigma_delta->spi->master);
20228a1d	326	iio_device_release_direct_mode(indio_dev);
af300848 LPC	327
	328	if (ret)
	329	return ret;
	330
	331	sample = raw_sample >> chan->scan_type.shift;
	332	sample &= (1 << chan->scan_type.realbits) - 1;
	333	*val = sample;
	334
	335	ret = ad_sigma_delta_postprocess_sample(sigma_delta, raw_sample);
	336	if (ret)
	337	return ret;
	338
	339	return IIO_VAL_INT;
	340	}
ef807729	341	EXPORT_SYMBOL_NS_GPL(ad_sigma_delta_single_conversion, IIO_AD_SIGMA_DELTA);
af300848 LPC	342
	343	static int ad_sd_buffer_postenable(struct iio_dev *indio_dev)
	344	{
	345	struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
8bea9af8	346	unsigned int i, slot, samples_buf_size;
af300848	347	unsigned int channel;
8bea9af8	348	uint8_t *samples_buf;
af300848 LPC	349	int ret;
af300848 LPC	350
8bea9af8 LPC	351	if (sigma_delta->num_slots == 1) {
	352	channel = find_first_bit(indio_dev->active_scan_mask,
	353	indio_dev->masklength);
	354	ret = ad_sigma_delta_set_channel(sigma_delta,
	355	indio_dev->channels[channel].address);
	356	if (ret)
	357	return ret;
	358	slot = 1;
	359	} else {
	360	/*
	361	* At this point update_scan_mode already enabled the required channels.
	362	* For sigma-delta sequencer drivers with multiple slots, an update_scan_mode
	363	* implementation is mandatory.
	364	*/
	365	slot = 0;
	366	for_each_set_bit(i, indio_dev->active_scan_mask, indio_dev->masklength) {
	367	sigma_delta->slots[slot] = indio_dev->channels[i].address;
	368	slot++;
	369	}
	370	}
	371
	372	sigma_delta->active_slots = slot;
	373	sigma_delta->current_slot = 0;
	374
	375	if (sigma_delta->active_slots > 1) {
	376	ret = ad_sigma_delta_append_status(sigma_delta, true);
	377	if (ret)
	378	return ret;
	379	}
	380
	381	samples_buf_size = ALIGN(slot * indio_dev->channels[0].scan_type.storagebits, 8);
	382	samples_buf_size += sizeof(int64_t);
	383	samples_buf = devm_krealloc(&sigma_delta->spi->dev, sigma_delta->samples_buf,
	384	samples_buf_size, GFP_KERNEL);
	385	if (!samples_buf)
	386	return -ENOMEM;
	387
	388	sigma_delta->samples_buf = samples_buf;
af300848 LPC	389
	390	spi_bus_lock(sigma_delta->spi->master);
	391	sigma_delta->bus_locked = true;
df1d80ae LPC	392	sigma_delta->keep_cs_asserted = true;
df1d80ae LPC	393
af300848 LPC	394	ret = ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_CONTINUOUS);
	395	if (ret)
	396	goto err_unlock;
	397
	398	sigma_delta->irq_dis = false;
	399	enable_irq(sigma_delta->spi->irq);
	400
	401	return 0;
	402
	403	err_unlock:
	404	spi_bus_unlock(sigma_delta->spi->master);
af300848 LPC	405
	406	return ret;
	407	}
	408
	409	static int ad_sd_buffer_postdisable(struct iio_dev *indio_dev)
	410	{
	411	struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
	412
16735d02	413	reinit_completion(&sigma_delta->completion);
af300848 LPC	414	wait_for_completion_timeout(&sigma_delta->completion, HZ);
	415
	416	if (!sigma_delta->irq_dis) {
	417	disable_irq_nosync(sigma_delta->spi->irq);
	418	sigma_delta->irq_dis = true;
	419	}
	420
df1d80ae	421	sigma_delta->keep_cs_asserted = false;
af300848 LPC	422	ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_IDLE);
af300848 LPC	423
8bea9af8 LPC	424	if (sigma_delta->status_appended)
	425	ad_sigma_delta_append_status(sigma_delta, false);
	426
	427	ad_sigma_delta_disable_all(sigma_delta);
af300848 LPC	428	sigma_delta->bus_locked = false;
	429	return spi_bus_unlock(sigma_delta->spi->master);
	430	}
	431
	432	static irqreturn_t ad_sd_trigger_handler(int irq, void *p)
	433	{
	434	struct iio_poll_func *pf = p;
	435	struct iio_dev *indio_dev = pf->indio_dev;
	436	struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
0fb6ee8d	437	uint8_t *data = sigma_delta->rx_buf;
8bea9af8 LPC	438	unsigned int transfer_size;
	439	unsigned int sample_size;
	440	unsigned int sample_pos;
	441	unsigned int status_pos;
af300848	442	unsigned int reg_size;
f0aef2d0	443	unsigned int data_reg;
af300848	444
af300848 LPC	445	reg_size = indio_dev->channels[0].scan_type.realbits +
	446	indio_dev->channels[0].scan_type.shift;
	447	reg_size = DIV_ROUND_UP(reg_size, 8);
	448
f0aef2d0 LPC	449	if (sigma_delta->info->data_reg != 0)
	450	data_reg = sigma_delta->info->data_reg;
	451	else
	452	data_reg = AD_SD_REG_DATA;
	453
8bea9af8 LPC	454	/* Status word will be appended to the sample during transfer */
	455	if (sigma_delta->status_appended)
	456	transfer_size = reg_size + 1;
	457	else
	458	transfer_size = reg_size;
	459
af300848 LPC	460	switch (reg_size) {
	461	case 4:
	462	case 2:
	463	case 1:
8bea9af8 LPC	464	status_pos = reg_size;
8bea9af8 LPC	465	ad_sd_read_reg_raw(sigma_delta, data_reg, transfer_size, &data[0]);
af300848 LPC	466	break;
af300848 LPC	467	case 3:
8bea9af8 LPC	468	/*
	469	* Data array after transfer will look like (if status is appended):
	470	* data[] = { [0][sample][sample][sample][status] }
	471	* Keeping the first byte 0 shifts the status postion by 1 byte to the right.
	472	*/
	473	status_pos = reg_size + 1;
	474
af300848 LPC	475	/* We store 24 bit samples in a 32 bit word. Keep the upper
af300848 LPC	476	* byte set to zero. */
8bea9af8	477	ad_sd_read_reg_raw(sigma_delta, data_reg, transfer_size, &data[1]);
af300848 LPC	478	break;
	479	}
	480
8bea9af8 LPC	481	/*
	482	* For devices sampling only one channel at
	483	* once, there is no need for sample number tracking.
	484	*/
	485	if (sigma_delta->active_slots == 1) {
	486	iio_push_to_buffers_with_timestamp(indio_dev, data, pf->timestamp);
	487	goto irq_handled;
	488	}
	489
	490	if (sigma_delta->status_appended) {
	491	u8 converted_channel;
	492
	493	converted_channel = data[status_pos] & sigma_delta->info->status_ch_mask;
	494	if (converted_channel != sigma_delta->slots[sigma_delta->current_slot]) {
	495	/*
	496	* Desync occurred during continuous sampling of multiple channels.
	497	* Drop this incomplete sample and start from first channel again.
	498	*/
	499
	500	sigma_delta->current_slot = 0;
	501	goto irq_handled;
	502	}
	503	}
	504
	505	sample_size = indio_dev->channels[0].scan_type.storagebits / 8;
	506	sample_pos = sample_size * sigma_delta->current_slot;
	507	memcpy(&sigma_delta->samples_buf[sample_pos], data, sample_size);
	508	sigma_delta->current_slot++;
af300848	509
8bea9af8 LPC	510	if (sigma_delta->current_slot == sigma_delta->active_slots) {
	511	sigma_delta->current_slot = 0;
	512	iio_push_to_buffers_with_timestamp(indio_dev, sigma_delta->samples_buf,
	513	pf->timestamp);
	514	}
	515
	516	irq_handled:
af300848 LPC	517	iio_trigger_notify_done(indio_dev->trig);
	518	sigma_delta->irq_dis = false;
	519	enable_irq(sigma_delta->spi->irq);
	520
	521	return IRQ_HANDLED;
	522	}
	523
8bea9af8 LPC	524	static bool ad_sd_validate_scan_mask(struct iio_dev indio_dev, const unsigned long mask)
	525	{
	526	struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
	527
	528	return bitmap_weight(mask, indio_dev->masklength) <= sigma_delta->num_slots;
	529	}
	530
af300848	531	static const struct iio_buffer_setup_ops ad_sd_buffer_setup_ops = {
af300848	532	.postenable = &ad_sd_buffer_postenable,
af300848	533	.postdisable = &ad_sd_buffer_postdisable,
8bea9af8	534	.validate_scan_mask = &ad_sd_validate_scan_mask,
af300848 LPC	535	};
	536
	537	static irqreturn_t ad_sd_data_rdy_trig_poll(int irq, void *private)
	538	{
	539	struct ad_sigma_delta *sigma_delta = private;
	540
	541	complete(&sigma_delta->completion);
	542	disable_irq_nosync(irq);
	543	sigma_delta->irq_dis = true;
398fd22b	544	iio_trigger_poll(sigma_delta->trig);
af300848 LPC	545
	546	return IRQ_HANDLED;
	547	}
	548
	549	/**
	550	* ad_sd_validate_trigger() - validate_trigger callback for ad_sigma_delta devices
	551	* @indio_dev: The IIO device
	552	* @trig: The new trigger
	553	*
	554	* Returns: 0 if the 'trig' matches the trigger registered by the ad_sigma_delta
	555	* device, -EINVAL otherwise.
	556	*/
	557	int ad_sd_validate_trigger(struct iio_dev indio_dev, struct iio_trigger trig)
	558	{
	559	struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
	560
	561	if (sigma_delta->trig != trig)
	562	return -EINVAL;
	563
	564	return 0;
	565	}
ef807729	566	EXPORT_SYMBOL_NS_GPL(ad_sd_validate_trigger, IIO_AD_SIGMA_DELTA);
af300848	567
718fb2bc AA	568	static int devm_ad_sd_probe_trigger(struct device dev, struct iio_dev indio_dev)
	569	{
	570	struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
	571	int ret;
	572
	573	if (dev != &sigma_delta->spi->dev) {
	574	dev_err(dev, "Trigger parent should be '%s', got '%s'\n",
	575	dev_name(dev), dev_name(&sigma_delta->spi->dev));
	576	return -EFAULT;
	577	}
	578
	579	sigma_delta->trig = devm_iio_trigger_alloc(dev, "%s-dev%d", indio_dev->name,
	580	iio_device_id(indio_dev));
	581	if (sigma_delta->trig == NULL)
	582	return -ENOMEM;
	583
718fb2bc AA	584	init_completion(&sigma_delta->completion);
	585
	586	sigma_delta->irq_dis = true;
	587	ret = devm_request_irq(dev, sigma_delta->spi->irq,
	588	ad_sd_data_rdy_trig_poll,
	589	sigma_delta->info->irq_flags \| IRQF_NO_AUTOEN,
	590	indio_dev->name,
	591	sigma_delta);
	592	if (ret)
	593	return ret;
	594
	595	iio_trigger_set_drvdata(sigma_delta->trig, sigma_delta);
	596
	597	ret = devm_iio_trigger_register(dev, sigma_delta->trig);
	598	if (ret)
	599	return ret;
	600
	601	/* select default trigger */
	602	indio_dev->trig = iio_trigger_get(sigma_delta->trig);
	603
	604	return 0;
	605	}
	606
718fb2bc AA	607	/**
	608	* devm_ad_sd_setup_buffer_and_trigger() - Device-managed buffer & trigger setup
	609	* @dev: Device object to which to bind the life-time of the resources attached
	610	* @indio_dev: The IIO device
	611	*/
	612	int devm_ad_sd_setup_buffer_and_trigger(struct device dev, struct iio_dev indio_dev)
	613	{
8bea9af8	614	struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
718fb2bc AA	615	int ret;
718fb2bc AA	616
8bea9af8 LPC	617	sigma_delta->slots = devm_kcalloc(dev, sigma_delta->num_slots,
	618	sizeof(*sigma_delta->slots), GFP_KERNEL);
	619	if (!sigma_delta->slots)
	620	return -ENOMEM;
	621
718fb2bc AA	622	ret = devm_iio_triggered_buffer_setup(dev, indio_dev,
	623	&iio_pollfunc_store_time,
	624	&ad_sd_trigger_handler,
	625	&ad_sd_buffer_setup_ops);
	626	if (ret)
	627	return ret;
	628
	629	return devm_ad_sd_probe_trigger(dev, indio_dev);
	630	}
ef807729	631	EXPORT_SYMBOL_NS_GPL(devm_ad_sd_setup_buffer_and_trigger, IIO_AD_SIGMA_DELTA);
718fb2bc	632
af300848 LPC	633	/**
	634	* ad_sd_init() - Initializes a ad_sigma_delta struct
	635	* @sigma_delta: The ad_sigma_delta device
	636	* @indio_dev: The IIO device which the Sigma Delta device is used for
	637	* @spi: The SPI device for the ad_sigma_delta device
	638	* @info: Device specific callbacks and options
	639	*
	640	* This function needs to be called before any other operations are performed on
	641	* the ad_sigma_delta struct.
	642	*/
	643	int ad_sd_init(struct ad_sigma_delta sigma_delta, struct iio_dev indio_dev,
	644	struct spi_device spi, const struct ad_sigma_delta_info info)
	645	{
	646	sigma_delta->spi = spi;
	647	sigma_delta->info = info;
8bea9af8 LPC	648
	649	/* If the field is unset in ad_sigma_delta_info, asume there can only be 1 slot. */
	650	if (!info->num_slots)
	651	sigma_delta->num_slots = 1;
	652	else
	653	sigma_delta->num_slots = info->num_slots;
	654
	655	if (sigma_delta->num_slots > 1) {
	656	if (!indio_dev->info->update_scan_mode) {
	657	dev_err(&spi->dev, "iio_dev lacks update_scan_mode().\n");
	658	return -EINVAL;
	659	}
	660
	661	if (!info->disable_all) {
	662	dev_err(&spi->dev, "ad_sigma_delta_info lacks disable_all().\n");
	663	return -EINVAL;
	664	}
	665	}
	666
af300848 LPC	667	iio_device_set_drvdata(indio_dev, sigma_delta);
	668
	669	return 0;
	670	}
ef807729	671	EXPORT_SYMBOL_NS_GPL(ad_sd_init, IIO_AD_SIGMA_DELTA);
af300848 LPC	672
	673	MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
	674	MODULE_DESCRIPTION("Analog Devices Sigma-Delta ADCs");
	675	MODULE_LICENSE("GPL v2");