diff mbox series

[v3,6/6] iio: adc: Add support for AD4000

Message ID e340f48324b0ea3afb1c715cb2fba184c27112a1.1717539384.git.marcelo.schmitt@analog.com (mailing list archive)
State Superseded
Headers show
Series Add support for AD4000 series of ADCs | expand

Commit Message

Marcelo Schmitt June 5, 2024, 11:14 a.m. UTC
Add support for AD4000 series of low noise, low power, high speed,
successive aproximation register (SAR) ADCs.

Signed-off-by: Marcelo Schmitt <marcelo.schmitt@analog.com>
---
 MAINTAINERS              |   1 +
 drivers/iio/adc/Kconfig  |  12 +
 drivers/iio/adc/Makefile |   1 +
 drivers/iio/adc/ad4000.c | 735 +++++++++++++++++++++++++++++++++++++++
 4 files changed, 749 insertions(+)
 create mode 100644 drivers/iio/adc/ad4000.c

Comments

Nuno Sá June 5, 2024, 1:03 p.m. UTC | #1
On Wed, 2024-06-05 at 08:14 -0300, Marcelo Schmitt wrote:
> Add support for AD4000 series of low noise, low power, high speed,
> successive aproximation register (SAR) ADCs.
> 
> Signed-off-by: Marcelo Schmitt <marcelo.schmitt@analog.com>
> ---

...

> +
> +static const struct ad4000_chip_info ad4000_chips[] = {
> +	[ID_AD4000] = {
> +		.dev_name = "ad4000",
> +		.chan_spec = AD4000_PSEUDO_DIFF_CHANNEL('u', 16),
> +	},
> +	[ID_AD4001] = {
> +		.dev_name = "ad4001",
> +		.chan_spec = AD4000_DIFF_CHANNEL('s', 16),
> +	},
> +	[ID_AD4002] = {
> +		.dev_name = "ad4002",
> +		.chan_spec = AD4000_PSEUDO_DIFF_CHANNEL('u', 18),
> +	},
> +	[ID_AD4003] = {
> +		.dev_name = "ad4003",
> +		.chan_spec = AD4000_DIFF_CHANNEL('s', 18),
> +	},
> +	[ID_AD4004] = {
> +		.dev_name = "ad4004",
> +		.chan_spec = AD4000_PSEUDO_DIFF_CHANNEL('u', 16),
> +	},
> +	[ID_AD4005] = {
> +		.dev_name = "ad4005",
> +		.chan_spec = AD4000_DIFF_CHANNEL('s', 16),
> +	},
> +	[ID_AD4006] = {
> +		.dev_name = "ad4006",
> +		.chan_spec = AD4000_PSEUDO_DIFF_CHANNEL('u', 18),
> +	},
> +	[ID_AD4007] = {
> +		.dev_name = "ad4007",
> +		.chan_spec = AD4000_DIFF_CHANNEL('s', 18),
> +	},
> +	[ID_AD4008] = {
> +		.dev_name = "ad4008",
> +		.chan_spec = AD4000_PSEUDO_DIFF_CHANNEL('u', 16),
> +	},
> +	[ID_AD4010] = {
> +		.dev_name = "ad4010",
> +		.chan_spec = AD4000_PSEUDO_DIFF_CHANNEL('u', 18),
> +	},
> +	[ID_AD4011] = {
> +		.dev_name = "ad4011",
> +		.chan_spec = AD4000_DIFF_CHANNEL('s', 18),
> +	},
> +	[ID_AD4020] = {
> +		.dev_name = "ad4020",
> +		.chan_spec = AD4000_DIFF_CHANNEL('s', 20),
> +	},
> +	[ID_AD4021] = {
> +		.dev_name = "ad4021",
> +		.chan_spec = AD4000_DIFF_CHANNEL('s', 20),
> +	},
> +	[ID_AD4022] = {
> +		.dev_name = "ad4022",
> +		.chan_spec = AD4000_DIFF_CHANNEL('s', 20),
> +	},
> +	[ID_ADAQ4001] = {
> +		.dev_name = "adaq4001",
> +		.chan_spec = AD4000_DIFF_CHANNEL('s', 16),
> +	},
> +	[ID_ADAQ4003] = {
> +		.dev_name = "adaq4003",
> +		.chan_spec = AD4000_DIFF_CHANNEL('s', 18),
> +	},
> +};
> +

Please have the above as a different variable per device rather than the array.
Likely no need for the enum then...
 
> +struct ad4000_state {
> +	struct spi_device *spi;
> +	struct gpio_desc *cnv_gpio;
> +	struct spi_transfer xfers[2];
> +	struct spi_message msg;
> +	int vref;
> +	enum ad4000_spi_mode spi_mode;
> +	bool span_comp;
> +	bool turbo_mode;
> +	int gain_milli;
> +	int scale_tbl[2][2];
> +
> +	/*
> +	 * DMA (thus cache coherency maintenance) requires the
> +	 * transfer buffers to live in their own cache lines.
> +	 */
> +	struct {
> +		union {
> +			__be16 sample_buf16;
> +			__be32 sample_buf32;
> +		} data;
> +		s64 timestamp __aligned(8);
> +	} scan __aligned(IIO_DMA_MINALIGN);
> +	__be16 tx_buf;
> +	__be16 rx_buf;
> +};
> +
> +static void ad4000_fill_scale_tbl(struct ad4000_state *st, int scale_bits,
> +				  const struct ad4000_chip_info *chip)
> +{
> +	int diff = chip->chan_spec.differential;
> +	int val, val2, tmp0, tmp1;
> +	u64 tmp2;
> +
> +	val2 = scale_bits;
> +	val = st->vref / 1000;
> +	/*
> +	 * The gain is stored as a fraction of 1000 and, as we need to
> +	 * divide vref by gain, we invert the gain/1000 fraction.
> +	 * Also multiply by an extra MILLI to avoid losing precision.
> +	 */
> +	val = mult_frac(val, MILLI * MILLI, st->gain_milli);

Why not MICRO :)?

> +	/* Would multiply by NANO here but we multiplied by extra MILLI */
> +	tmp2 = shift_right((u64)val * MICRO, val2);
> +	tmp0 = (int)div_s64_rem(tmp2, NANO, &tmp1);

no cast needed...

> +	/* Store scale for when span compression is disabled */
> +	st->scale_tbl[0][0] = tmp0; /* Integer part */
> +	st->scale_tbl[0][1] = abs(tmp1); /* Fractional part */
> +	/* Store scale for when span compression is enabled */
> +	st->scale_tbl[1][0] = tmp0;
> +	/* The integer part is always zero so don't bother to divide it. */
> +	if (diff)
> +		st->scale_tbl[1][1] = DIV_ROUND_CLOSEST(abs(tmp1) * 4, 5);
> +	else
> +		st->scale_tbl[1][1] = DIV_ROUND_CLOSEST(abs(tmp1) * 9, 10);
> +}
> +
> +static int ad4000_write_reg(struct ad4000_state *st, uint8_t val)
> +{
> +	st->tx_buf = cpu_to_be16(AD4000_WRITE_COMMAND << BITS_PER_BYTE |
> val);
> +	return spi_write(st->spi, &st->tx_buf, 2);

sizeof(tx_buf)?

> +}
> +
> +static int ad4000_read_reg(struct ad4000_state *st, unsigned int *val)
> +{
> +	struct spi_transfer t[] = {
> +		{
> +			.tx_buf = &st->tx_buf,
> +			.rx_buf = &st->rx_buf,
> +			.len = 2,
> +		},
> +	};
> +	int ret;
> +
> +	st->tx_buf = cpu_to_be16(AD4000_READ_COMMAND << BITS_PER_BYTE);
> +	ret = spi_sync_transfer(st->spi, t, ARRAY_SIZE(t));
> +	if (ret < 0)
> +		return ret;
> +
> +	*val = be16_to_cpu(st->rx_buf);
> +
> +	return ret;
> +}
> +
> +static void ad4000_unoptimize_msg(void *msg)
> +{
> +	spi_unoptimize_message(msg);
> +}
> +
> +/*
> + * This executes a data sample transfer for when the device connections are
> + * in "3-wire" mode, selected by setting the adi,spi-mode device tree
> property
> + * to "single". In this connection mode, the ADC SDI pin is connected to MOSI
> or
> + * to VIO and ADC CNV pin is connected either to a SPI controller CS or to a
> GPIO.
> + * AD4000 series of devices initiate conversions on the rising edge of CNV
> pin.
> + *
> + * If the CNV pin is connected to an SPI controller CS line (which is by
> default
> + * active low), the ADC readings would have a latency (delay) of one read.
> + * Moreover, since we also do ADC sampling for filling the buffer on
> triggered
> + * buffer mode, the timestamps of buffer readings would be disarranged.
> + * To prevent the read latency and reduce the time discrepancy between the
> + * sample read request and the time of actual sampling by the ADC, do a
> + * preparatory transfer to pulse the CS/CNV line.
> + */
> +static int ad4000_prepare_3wire_mode_message(struct ad4000_state *st,
> +					     const struct iio_chan_spec
> *chan)
> +{
> +	unsigned int cnv_pulse_time = st->turbo_mode ? AD4000_TQUIET1_NS
> +						     : AD4000_TCONV_NS;
> +	struct spi_transfer *xfers = st->xfers;
> +	int ret;
> +
> +	xfers[0].cs_change = 1;
> +	xfers[0].cs_change_delay.value = cnv_pulse_time;
> +	xfers[0].cs_change_delay.unit = SPI_DELAY_UNIT_NSECS;
> +
> +	xfers[1].rx_buf = &st->scan.data;
> +	xfers[1].len = BITS_TO_BYTES(chan->scan_type.storagebits);
> +	xfers[1].delay.value = AD4000_TQUIET2_NS;
> +	xfers[1].delay.unit = SPI_DELAY_UNIT_NSECS;
> +
> +	spi_message_init_with_transfers(&st->msg, st->xfers, 2);
> +
> +	ret = spi_optimize_message(st->spi, &st->msg);
> +	if (ret)
> +		return ret;
> +
> +	return devm_add_action_or_reset(&st->spi->dev, ad4000_unoptimize_msg,
> +					&st->msg);
> +}
> +
> +/*
> + * This executes a data sample transfer for when the device connections are
> + * in "4-wire" mode, selected when the adi,spi-mode device tree
> + * property is absent or empty. In this connection mode, the controller CS
> pin
> + * is connected to ADC SDI pin and a GPIO is connected to ADC CNV pin.
> + * The GPIO connected to ADC CNV pin is set outside of the SPI transfer.
> + */
> +static int ad4000_prepare_4wire_mode_message(struct ad4000_state *st,
> +					     const struct iio_chan_spec
> *chan)
> +{
> +	unsigned int cnv_to_sdi_time = st->turbo_mode ? AD4000_TQUIET1_NS
> +						      : AD4000_TCONV_NS;
> +	struct spi_transfer *xfers = st->xfers;
> +	int ret;
> +
> +	/*
> +	 * Dummy transfer to cause enough delay between CNV going high and
> SDI
> +	 * going low.
> +	 */
> +	xfers[0].cs_off = 1;
> +	xfers[0].delay.value = cnv_to_sdi_time;
> +	xfers[0].delay.unit = SPI_DELAY_UNIT_NSECS;
> +
> +	xfers[1].rx_buf = &st->scan.data;
> +	xfers[1].len = BITS_TO_BYTES(chan->scan_type.storagebits);
> +
> +	spi_message_init_with_transfers(&st->msg, st->xfers, 2);
> +
> +	ret = spi_optimize_message(st->spi, &st->msg);
> +	if (ret)
> +		return ret;
> +
> +	return devm_add_action_or_reset(&st->spi->dev, ad4000_unoptimize_msg,
> +					&st->msg);
> +}
> +
> +static int ad4000_convert_and_acquire(struct ad4000_state *st)
> +{
> +	int ret;
> +
> +	/*
> +	 * In 4-wire mode, the CNV line is held high for the entire
> conversion
> +	 * and acquisition process. In other modes st->cnv_gpio is NULL and
> is
> +	 * ignored (CS is wired to CNV in those cases).
> +	 */
> +	gpiod_set_value_cansleep(st->cnv_gpio, 1);

Not sure it's a good practise to assume internal details as you're going for
GPIO. I would prefer to have an explicit check for st->cnv_gpio being NULL or
not.
  
> +	ret = spi_sync(st->spi, &st->msg);
> +	gpiod_set_value_cansleep(st->cnv_gpio, 0);
> +
> +	return ret;
> +}
> +
> +static int ad4000_single_conversion(struct iio_dev *indio_dev,
> +				    const struct iio_chan_spec *chan, int
> *val)
> +{
> +	struct ad4000_state *st = iio_priv(indio_dev);
> +	u32 sample;
> +	int ret;
> +
> +	ret = ad4000_convert_and_acquire(st);
> 

no error check

> +	if (chan->scan_type.storagebits > 16)
> +		sample = be32_to_cpu(st->scan.data.sample_buf32);
> +	else
> +		sample = be16_to_cpu(st->scan.data.sample_buf16);
> +
> +	switch (chan->scan_type.realbits) {
> +	case 16:
> +		break;
> +	case 18:
> +		sample = FIELD_GET(AD4000_18BIT_MSK, sample);
> +		break;
> +	case 20:
> +		sample = FIELD_GET(AD4000_20BIT_MSK, sample);
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	if (chan->scan_type.sign == 's')
> +		*val = sign_extend32(sample, chan->scan_type.realbits - 1);
> +
> +	return IIO_VAL_INT;
> +}
> +
> +static int ad4000_read_raw(struct iio_dev *indio_dev,
> +			   struct iio_chan_spec const *chan, int *val,
> +			   int *val2, long info)
> +{
> +	struct ad4000_state *st = iio_priv(indio_dev);
> +
> +	switch (info) {
> +	case IIO_CHAN_INFO_RAW:
> +		iio_device_claim_direct_scoped(return -EBUSY, indio_dev)
> +			return ad4000_single_conversion(indio_dev, chan,
> val);
> +		unreachable();
> +	case IIO_CHAN_INFO_SCALE:
> +		*val = st->scale_tbl[st->span_comp][0];
> +		*val2 = st->scale_tbl[st->span_comp][1];
> +		return IIO_VAL_INT_PLUS_NANO;
> +	case IIO_CHAN_INFO_OFFSET:
> +		*val = 0;
> +		if (st->span_comp)
> +			*val = mult_frac(st->vref / 1000, 1, 10);
> +
> +		return IIO_VAL_INT;
> +	default:
> +		return -EINVAL;
> +	}
> +}
> +
> +static int ad4000_read_avail(struct iio_dev *indio_dev,
> +			     struct iio_chan_spec const *chan,
> +			     const int **vals, int *type, int *length,
> +			     long info)
> +{
> +	struct ad4000_state *st = iio_priv(indio_dev);
> +
> +	switch (info) {
> +	case IIO_CHAN_INFO_SCALE:
> +		*vals = (int *)st->scale_tbl;
> +		*length = 2 * 2;
> +		*type = IIO_VAL_INT_PLUS_NANO;
> +		return IIO_AVAIL_LIST;
> +	default:
> +		return -EINVAL;
> +	}
> +}
> +
> +static int ad4000_write_raw_get_fmt(struct iio_dev *indio_dev,
> +				    struct iio_chan_spec const *chan, long
> mask)
> +{
> +	switch (mask) {
> +	case IIO_CHAN_INFO_SCALE:
> +		return IIO_VAL_INT_PLUS_NANO;
> +	default:
> +		return IIO_VAL_INT_PLUS_MICRO;
> +	}
> +}
> +
> +static int ad4000_write_raw(struct iio_dev *indio_dev,
> +			    struct iio_chan_spec const *chan, int val, int
> val2,
> +			    long mask)
> +{
> +	struct ad4000_state *st = iio_priv(indio_dev);
> +	unsigned int reg_val;
> +	bool span_comp_en;
> +	int ret;
> +
> +	switch (mask) {
> +	case IIO_CHAN_INFO_SCALE:
> +		iio_device_claim_direct_scoped(return -EBUSY, indio_dev) {
> +			ret = ad4000_read_reg(st, &reg_val);
> +			if (ret < 0)
> +				return ret;
> +
> +			span_comp_en = (val2 == st->scale_tbl[1][1]);

no () needed

> +			reg_val &= ~AD4000_CFG_SPAN_COMP;
> +			reg_val |= FIELD_PREP(AD4000_CFG_SPAN_COMP,
> span_comp_en);
> +
> +			ret = ad4000_write_reg(st, reg_val);
> +			if (ret < 0)
> +				return ret;
> +
> +			st->span_comp = span_comp_en;
> +			return 0;
> +		}
> +		unreachable();
> +	default:
> +		return -EINVAL;
> +	}
> +}
> +
> +static irqreturn_t ad4000_trigger_handler(int irq, void *p)
> +{
> +	struct iio_poll_func *pf = p;
> +	struct iio_dev *indio_dev = pf->indio_dev;
> +	struct ad4000_state *st = iio_priv(indio_dev);
> +	int ret;
> +
> +	ret = ad4000_convert_and_acquire(st);
> +	if (ret < 0)
> +		goto err_out;
> +
> +	iio_push_to_buffers_with_timestamp(indio_dev, &st->scan,
> +					   iio_get_time_ns(indio_dev));
> +
> +err_out:
> +	iio_trigger_notify_done(indio_dev->trig);
> +	return IRQ_HANDLED;
> +}
> +
> +static int ad4000_reg_access(struct iio_dev *indio_dev, unsigned int reg,
> +			     unsigned int writeval, unsigned int *readval)
> +{
> +	struct ad4000_state *st = iio_priv(indio_dev);
> +	int ret;
> +
> +	if (readval)
> +		ret = ad4000_read_reg(st, readval);
> +	else
> +		ret = ad4000_write_reg(st, writeval);

if (readval)
	return ad4000_read_reg();

return ad4000_write_reg();


> +
> +	return ret;
> +}
> +
> +static const struct iio_info ad4000_info = {
> +	.read_raw = &ad4000_read_raw,
> +	.read_avail = &ad4000_read_avail,
> +	.write_raw = &ad4000_write_raw,
> +	.write_raw_get_fmt = &ad4000_write_raw_get_fmt,
> +	.debugfs_reg_access = &ad4000_reg_access,
> +
> +};
> +
> +static int ad4000_config(struct ad4000_state *st)
> +{
> +	unsigned int reg_val;
> +
> +	if (device_property_present(&st->spi->dev, "adi,high-z-input"))
> +		reg_val |= FIELD_PREP(AD4000_CFG_HIGHZ, 1);
> +
> +	/*
> +	 * The ADC SDI pin might be connected to controller CS line in which
> +	 * case the write might fail. This, however, does not prevent the
> device
> +	 * from functioning even though in a configuration other than the
> +	 * requested one.
> +	 */

This raises the question if there's any way to describe that through DT (if not
doing it already)? So that, if SDI is connected to CS we don't even call this?
Other question that comes to mind is that in case SDI is connected to CS, will
all writes fail? Because if that's the case we other writes (like scale) that
won't work and we should take care of that...

> +	return ad4000_write_reg(st, reg_val);
> +}
> +
> +static void ad4000_regulator_disable(void *reg)
> +{
> +	regulator_disable(reg);
> +}
> +
> +static int ad4000_probe(struct spi_device *spi)
> +{
> +	const struct ad4000_chip_info *chip;
> +	struct regulator *vref_reg;
> +	struct iio_dev *indio_dev;
> +	struct ad4000_state *st;
> +	int ret;
> +
> +	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
> +	if (!indio_dev)
> +		return -ENOMEM;
> +
> +	chip = spi_get_device_match_data(spi);
> +	if (!chip)
> +		return -EINVAL;
> +
> +	st = iio_priv(indio_dev);
> +	st->spi = spi;
> +
> +	ret = devm_regulator_get_enable(&spi->dev, "vdd");
> +	if (ret)
> +		return dev_err_probe(&spi->dev, ret, "Failed to enable VDD
> supply\n");
> +
> +	ret = devm_regulator_get_enable(&spi->dev, "vio");
> +	if (ret)
> +		return dev_err_probe(&spi->dev, ret, "Failed to enable VIO
> supply\n");
> +
> +	vref_reg = devm_regulator_get(&spi->dev, "ref");
> +	if (IS_ERR(vref_reg))
> +		return dev_err_probe(&spi->dev, PTR_ERR(vref_reg),
> +				     "Failed to get vref regulator\n");

Should this not be an optional one? If not, why not devm_regulator_get_enable()?
Also consider the new devm_regulator_get_enable_read_voltage() - you need to
handle -ENODEV in case this is optional. 

> +
> +	ret = regulator_enable(vref_reg);
> +	if (ret < 0)
> +		return dev_err_probe(&spi->dev, ret,
> +				     "Failed to enable voltage regulator\n");
> +
> +	ret = devm_add_action_or_reset(&spi->dev, ad4000_regulator_disable,
> vref_reg);
> +	if (ret)
> +		return dev_err_probe(&spi->dev, ret,
> +				     "Failed to add regulator disable
> action\n");
> +
> +	st->vref = regulator_get_voltage(vref_reg);
> +	if (st->vref < 0)
> +		return dev_err_probe(&spi->dev, st->vref, "Failed to get
> vref\n");
> +

I think in all places you're using this you st->vref / 1000, right? Do it here
just once...

> +	st->cnv_gpio = devm_gpiod_get_optional(&spi->dev, "cnv",
> GPIOD_OUT_HIGH);
> +	if (IS_ERR(st->cnv_gpio))
> +		return dev_err_probe(&spi->dev, PTR_ERR(st->cnv_gpio),
> +				     "Failed to get CNV GPIO");
> +
> +	ret = device_property_match_property_string(&spi->dev, "adi,spi-
> mode",
> +						    ad4000_spi_modes,
> +						   
> ARRAY_SIZE(ad4000_spi_modes));
> +	/* Default to 4-wire mode if adi,spi-mode property is not present */
> +	if (ret == -EINVAL)
> +		st->spi_mode = AD4000_SPI_MODE_DEFAULT;
> +	else if (ret < 0)
> +		return dev_err_probe(&spi->dev, ret,
> +				     "getting adi,spi-mode property
> failed\n");
> +	else
> +		st->spi_mode = ret;
> +
> +	switch (st->spi_mode) {
> +	case AD4000_SPI_MODE_DEFAULT:
> +		ret = ad4000_prepare_4wire_mode_message(st, &chip-
> >chan_spec);
> +		if (ret)
> +			return ret;
> +
> +		break;
> +	case AD4000_SPI_MODE_SINGLE:
> +		ret = ad4000_prepare_3wire_mode_message(st, &chip-
> >chan_spec);
> +		if (ret)
> +			return ret;
> +
> +		/*
> +		 * In "3-wire mode", the ADC SDI line must be kept high when
> +		 * data is not being clocked out of the controller.
> +		 * Request the SPI controller to make MOSI idle high.
> +		 */
> +		spi->mode = SPI_MODE_0 | SPI_MOSI_IDLE_HIGH;
> +		if (spi_setup(spi))
> +			dev_warn(&st->spi->dev, "SPI controller setup
> failed\n");

Does not look like a warn to me... Also, spi_setup() should already print an
error message so this will duplicate that.

> +
> +		break;
> +	}
> +
> +	ret = ad4000_config(st);
> +	if (ret < 0)
> +		dev_dbg(&st->spi->dev, "Failed to config device\n");

Also questionable but see the my comment on ad4000_config(). In any case this
should be visible to the user so I would at least use dev_warn().

> +
> +	indio_dev->name = chip->dev_name;
> +	indio_dev->info = &ad4000_info;
> +	indio_dev->channels = &chip->chan_spec;
> +	indio_dev->num_channels = 1;
> +
> +	/* Hardware gain only applies to ADAQ devices */
> +	st->gain_milli = 1000;
> +	if (device_property_present(&spi->dev, "adi,gain-milli")) {
> +
> +		ret = device_property_read_u32(&spi->dev, "adi,gain-milli",
> +					       &st->gain_milli);

Can we have full unsigned int range for the gain? I guess not :)


- Nuno Sá
kernel test robot June 5, 2024, 8:50 p.m. UTC | #2
Hi Marcelo,

kernel test robot noticed the following build warnings:

[auto build test WARNING on broonie-spi/for-next]
[also build test WARNING on jic23-iio/togreg linus/master v6.10-rc2 next-20240605]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Marcelo-Schmitt/spi-Add-SPI-mode-bit-for-MOSI-idle-state-configuration/20240605-231912
base:   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git for-next
patch link:    https://lore.kernel.org/r/e340f48324b0ea3afb1c715cb2fba184c27112a1.1717539384.git.marcelo.schmitt%40analog.com
patch subject: [PATCH v3 6/6] iio: adc: Add support for AD4000
config: alpha-allyesconfig (https://download.01.org/0day-ci/archive/20240606/202406060440.I43MwC4B-lkp@intel.com/config)
compiler: alpha-linux-gcc (GCC) 13.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240606/202406060440.I43MwC4B-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202406060440.I43MwC4B-lkp@intel.com/

All warnings (new ones prefixed by >>):

   drivers/iio/adc/ad4000.c: In function 'ad4000_single_conversion':
>> drivers/iio/adc/ad4000.c:375:13: warning: variable 'ret' set but not used [-Wunused-but-set-variable]
     375 |         int ret;
         |             ^~~


vim +/ret +375 drivers/iio/adc/ad4000.c

   369	
   370	static int ad4000_single_conversion(struct iio_dev *indio_dev,
   371					    const struct iio_chan_spec *chan, int *val)
   372	{
   373		struct ad4000_state *st = iio_priv(indio_dev);
   374		u32 sample;
 > 375		int ret;
   376	
   377		ret = ad4000_convert_and_acquire(st);
   378	
   379		if (chan->scan_type.storagebits > 16)
   380			sample = be32_to_cpu(st->scan.data.sample_buf32);
   381		else
   382			sample = be16_to_cpu(st->scan.data.sample_buf16);
   383	
   384		switch (chan->scan_type.realbits) {
   385		case 16:
   386			break;
   387		case 18:
   388			sample = FIELD_GET(AD4000_18BIT_MSK, sample);
   389			break;
   390		case 20:
   391			sample = FIELD_GET(AD4000_20BIT_MSK, sample);
   392			break;
   393		default:
   394			return -EINVAL;
   395		}
   396	
   397		if (chan->scan_type.sign == 's')
   398			*val = sign_extend32(sample, chan->scan_type.realbits - 1);
   399	
   400		return IIO_VAL_INT;
   401	}
   402
kernel test robot June 5, 2024, 9:32 p.m. UTC | #3
Hi Marcelo,

kernel test robot noticed the following build warnings:

[auto build test WARNING on broonie-spi/for-next]
[also build test WARNING on jic23-iio/togreg linus/master v6.10-rc2 next-20240605]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Marcelo-Schmitt/spi-Add-SPI-mode-bit-for-MOSI-idle-state-configuration/20240605-231912
base:   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git for-next
patch link:    https://lore.kernel.org/r/e340f48324b0ea3afb1c715cb2fba184c27112a1.1717539384.git.marcelo.schmitt%40analog.com
patch subject: [PATCH v3 6/6] iio: adc: Add support for AD4000
config: hexagon-allmodconfig (https://download.01.org/0day-ci/archive/20240606/202406060558.kJtbRid3-lkp@intel.com/config)
compiler: clang version 19.0.0git (https://github.com/llvm/llvm-project d7d2d4f53fc79b4b58e8d8d08151b577c3699d4a)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240606/202406060558.kJtbRid3-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202406060558.kJtbRid3-lkp@intel.com/

All warnings (new ones prefixed by >>):

   In file included from drivers/iio/adc/ad4000.c:17:
   In file included from include/linux/regulator/consumer.h:35:
   In file included from include/linux/suspend.h:5:
   In file included from include/linux/swap.h:9:
   In file included from include/linux/memcontrol.h:13:
   In file included from include/linux/cgroup.h:26:
   In file included from include/linux/kernel_stat.h:9:
   In file included from include/linux/interrupt.h:11:
   In file included from include/linux/hardirq.h:11:
   In file included from ./arch/hexagon/include/generated/asm/hardirq.h:1:
   In file included from include/asm-generic/hardirq.h:17:
   In file included from include/linux/irq.h:20:
   In file included from include/linux/io.h:14:
   In file included from arch/hexagon/include/asm/io.h:328:
   include/asm-generic/io.h:548:31: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     548 |         val = __raw_readb(PCI_IOBASE + addr);
         |                           ~~~~~~~~~~ ^
   include/asm-generic/io.h:561:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     561 |         val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE + addr));
         |                                                         ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/little_endian.h:37:51: note: expanded from macro '__le16_to_cpu'
      37 | #define __le16_to_cpu(x) ((__force __u16)(__le16)(x))
         |                                                   ^
   In file included from drivers/iio/adc/ad4000.c:17:
   In file included from include/linux/regulator/consumer.h:35:
   In file included from include/linux/suspend.h:5:
   In file included from include/linux/swap.h:9:
   In file included from include/linux/memcontrol.h:13:
   In file included from include/linux/cgroup.h:26:
   In file included from include/linux/kernel_stat.h:9:
   In file included from include/linux/interrupt.h:11:
   In file included from include/linux/hardirq.h:11:
   In file included from ./arch/hexagon/include/generated/asm/hardirq.h:1:
   In file included from include/asm-generic/hardirq.h:17:
   In file included from include/linux/irq.h:20:
   In file included from include/linux/io.h:14:
   In file included from arch/hexagon/include/asm/io.h:328:
   include/asm-generic/io.h:574:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     574 |         val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr));
         |                                                         ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/little_endian.h:35:51: note: expanded from macro '__le32_to_cpu'
      35 | #define __le32_to_cpu(x) ((__force __u32)(__le32)(x))
         |                                                   ^
   In file included from drivers/iio/adc/ad4000.c:17:
   In file included from include/linux/regulator/consumer.h:35:
   In file included from include/linux/suspend.h:5:
   In file included from include/linux/swap.h:9:
   In file included from include/linux/memcontrol.h:13:
   In file included from include/linux/cgroup.h:26:
   In file included from include/linux/kernel_stat.h:9:
   In file included from include/linux/interrupt.h:11:
   In file included from include/linux/hardirq.h:11:
   In file included from ./arch/hexagon/include/generated/asm/hardirq.h:1:
   In file included from include/asm-generic/hardirq.h:17:
   In file included from include/linux/irq.h:20:
   In file included from include/linux/io.h:14:
   In file included from arch/hexagon/include/asm/io.h:328:
   include/asm-generic/io.h:585:33: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     585 |         __raw_writeb(value, PCI_IOBASE + addr);
         |                             ~~~~~~~~~~ ^
   include/asm-generic/io.h:595:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     595 |         __raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE + addr);
         |                                                       ~~~~~~~~~~ ^
   include/asm-generic/io.h:605:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     605 |         __raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE + addr);
         |                                                       ~~~~~~~~~~ ^
   In file included from drivers/iio/adc/ad4000.c:17:
   In file included from include/linux/regulator/consumer.h:35:
   In file included from include/linux/suspend.h:5:
   In file included from include/linux/swap.h:9:
   In file included from include/linux/memcontrol.h:21:
   In file included from include/linux/mm.h:2253:
   include/linux/vmstat.h:514:36: warning: arithmetic between different enumeration types ('enum node_stat_item' and 'enum lru_list') [-Wenum-enum-conversion]
     514 |         return node_stat_name(NR_LRU_BASE + lru) + 3; // skip "nr_"
         |                               ~~~~~~~~~~~ ^ ~~~
   drivers/iio/adc/ad4000.c:375:6: warning: variable 'ret' set but not used [-Wunused-but-set-variable]
     375 |         int ret;
         |             ^
>> drivers/iio/adc/ad4000.c:538:3: warning: variable 'reg_val' is uninitialized when used here [-Wuninitialized]
     538 |                 reg_val |= FIELD_PREP(AD4000_CFG_HIGHZ, 1);
         |                 ^~~~~~~
   drivers/iio/adc/ad4000.c:535:22: note: initialize the variable 'reg_val' to silence this warning
     535 |         unsigned int reg_val;
         |                             ^
         |                              = 0
   9 warnings generated.


vim +/reg_val +538 drivers/iio/adc/ad4000.c

   369	
   370	static int ad4000_single_conversion(struct iio_dev *indio_dev,
   371					    const struct iio_chan_spec *chan, int *val)
   372	{
   373		struct ad4000_state *st = iio_priv(indio_dev);
   374		u32 sample;
 > 375		int ret;
   376	
   377		ret = ad4000_convert_and_acquire(st);
   378	
   379		if (chan->scan_type.storagebits > 16)
   380			sample = be32_to_cpu(st->scan.data.sample_buf32);
   381		else
   382			sample = be16_to_cpu(st->scan.data.sample_buf16);
   383	
   384		switch (chan->scan_type.realbits) {
   385		case 16:
   386			break;
   387		case 18:
   388			sample = FIELD_GET(AD4000_18BIT_MSK, sample);
   389			break;
   390		case 20:
   391			sample = FIELD_GET(AD4000_20BIT_MSK, sample);
   392			break;
   393		default:
   394			return -EINVAL;
   395		}
   396	
   397		if (chan->scan_type.sign == 's')
   398			*val = sign_extend32(sample, chan->scan_type.realbits - 1);
   399	
   400		return IIO_VAL_INT;
   401	}
   402	
   403	static int ad4000_read_raw(struct iio_dev *indio_dev,
   404				   struct iio_chan_spec const *chan, int *val,
   405				   int *val2, long info)
   406	{
   407		struct ad4000_state *st = iio_priv(indio_dev);
   408	
   409		switch (info) {
   410		case IIO_CHAN_INFO_RAW:
   411			iio_device_claim_direct_scoped(return -EBUSY, indio_dev)
   412				return ad4000_single_conversion(indio_dev, chan, val);
   413			unreachable();
   414		case IIO_CHAN_INFO_SCALE:
   415			*val = st->scale_tbl[st->span_comp][0];
   416			*val2 = st->scale_tbl[st->span_comp][1];
   417			return IIO_VAL_INT_PLUS_NANO;
   418		case IIO_CHAN_INFO_OFFSET:
   419			*val = 0;
   420			if (st->span_comp)
   421				*val = mult_frac(st->vref / 1000, 1, 10);
   422	
   423			return IIO_VAL_INT;
   424		default:
   425			return -EINVAL;
   426		}
   427	}
   428	
   429	static int ad4000_read_avail(struct iio_dev *indio_dev,
   430				     struct iio_chan_spec const *chan,
   431				     const int **vals, int *type, int *length,
   432				     long info)
   433	{
   434		struct ad4000_state *st = iio_priv(indio_dev);
   435	
   436		switch (info) {
   437		case IIO_CHAN_INFO_SCALE:
   438			*vals = (int *)st->scale_tbl;
   439			*length = 2 * 2;
   440			*type = IIO_VAL_INT_PLUS_NANO;
   441			return IIO_AVAIL_LIST;
   442		default:
   443			return -EINVAL;
   444		}
   445	}
   446	
   447	static int ad4000_write_raw_get_fmt(struct iio_dev *indio_dev,
   448					    struct iio_chan_spec const *chan, long mask)
   449	{
   450		switch (mask) {
   451		case IIO_CHAN_INFO_SCALE:
   452			return IIO_VAL_INT_PLUS_NANO;
   453		default:
   454			return IIO_VAL_INT_PLUS_MICRO;
   455		}
   456	}
   457	
   458	static int ad4000_write_raw(struct iio_dev *indio_dev,
   459				    struct iio_chan_spec const *chan, int val, int val2,
   460				    long mask)
   461	{
   462		struct ad4000_state *st = iio_priv(indio_dev);
   463		unsigned int reg_val;
   464		bool span_comp_en;
   465		int ret;
   466	
   467		switch (mask) {
   468		case IIO_CHAN_INFO_SCALE:
   469			iio_device_claim_direct_scoped(return -EBUSY, indio_dev) {
   470				ret = ad4000_read_reg(st, &reg_val);
   471				if (ret < 0)
   472					return ret;
   473	
   474				span_comp_en = (val2 == st->scale_tbl[1][1]);
   475				reg_val &= ~AD4000_CFG_SPAN_COMP;
   476				reg_val |= FIELD_PREP(AD4000_CFG_SPAN_COMP, span_comp_en);
   477	
   478				ret = ad4000_write_reg(st, reg_val);
   479				if (ret < 0)
   480					return ret;
   481	
   482				st->span_comp = span_comp_en;
   483				return 0;
   484			}
   485			unreachable();
   486		default:
   487			return -EINVAL;
   488		}
   489	}
   490	
   491	static irqreturn_t ad4000_trigger_handler(int irq, void *p)
   492	{
   493		struct iio_poll_func *pf = p;
   494		struct iio_dev *indio_dev = pf->indio_dev;
   495		struct ad4000_state *st = iio_priv(indio_dev);
   496		int ret;
   497	
   498		ret = ad4000_convert_and_acquire(st);
   499		if (ret < 0)
   500			goto err_out;
   501	
   502		iio_push_to_buffers_with_timestamp(indio_dev, &st->scan,
   503						   iio_get_time_ns(indio_dev));
   504	
   505	err_out:
   506		iio_trigger_notify_done(indio_dev->trig);
   507		return IRQ_HANDLED;
   508	}
   509	
   510	static int ad4000_reg_access(struct iio_dev *indio_dev, unsigned int reg,
   511				     unsigned int writeval, unsigned int *readval)
   512	{
   513		struct ad4000_state *st = iio_priv(indio_dev);
   514		int ret;
   515	
   516		if (readval)
   517			ret = ad4000_read_reg(st, readval);
   518		else
   519			ret = ad4000_write_reg(st, writeval);
   520	
   521		return ret;
   522	}
   523	
   524	static const struct iio_info ad4000_info = {
   525		.read_raw = &ad4000_read_raw,
   526		.read_avail = &ad4000_read_avail,
   527		.write_raw = &ad4000_write_raw,
   528		.write_raw_get_fmt = &ad4000_write_raw_get_fmt,
   529		.debugfs_reg_access = &ad4000_reg_access,
   530	
   531	};
   532	
   533	static int ad4000_config(struct ad4000_state *st)
   534	{
   535		unsigned int reg_val;
   536	
   537		if (device_property_present(&st->spi->dev, "adi,high-z-input"))
 > 538			reg_val |= FIELD_PREP(AD4000_CFG_HIGHZ, 1);
   539	
   540		/*
   541		 * The ADC SDI pin might be connected to controller CS line in which
   542		 * case the write might fail. This, however, does not prevent the device
   543		 * from functioning even though in a configuration other than the
   544		 * requested one.
   545		 */
   546		return ad4000_write_reg(st, reg_val);
   547	}
   548
Jonathan Cameron June 9, 2024, 9:23 a.m. UTC | #4
> > +
> > +static int ad4000_convert_and_acquire(struct ad4000_state *st)
> > +{
> > +	int ret;
> > +
> > +	/*
> > +	 * In 4-wire mode, the CNV line is held high for the entire
> > conversion
> > +	 * and acquisition process. In other modes st->cnv_gpio is NULL and
> > is
> > +	 * ignored (CS is wired to CNV in those cases).
> > +	 */
> > +	gpiod_set_value_cansleep(st->cnv_gpio, 1);  
> 
> Not sure it's a good practise to assume internal details as you're going for
> GPIO. I would prefer to have an explicit check for st->cnv_gpio being NULL or
> not.

Hmm. I had it in my head that this was documented behaviour, but
I can't find such in the docs, so agreed checking it makes sense.

I would be very surprised if this ever changed as it's one of the
things that makes optional gpios easy to work with but who knows!

+CC Linus and Bartosz for feedback on this one.


>   
> > +	ret = spi_sync(st->spi, &st->msg);
> > +	gpiod_set_value_cansleep(st->cnv_gpio, 0);
> > +
> > +	return ret;
> > +}
> > +

> > +static int ad4000_config(struct ad4000_state *st)
> > +{
> > +	unsigned int reg_val;
> > +
> > +	if (device_property_present(&st->spi->dev, "adi,high-z-input"))
> > +		reg_val |= FIELD_PREP(AD4000_CFG_HIGHZ, 1);
> > +
> > +	/*
> > +	 * The ADC SDI pin might be connected to controller CS line in which
> > +	 * case the write might fail. This, however, does not prevent the
> > device
> > +	 * from functioning even though in a configuration other than the
> > +	 * requested one.
> > +	 */  
> 
> This raises the question if there's any way to describe that through DT (if not
> doing it already)? So that, if SDI is connected to CS we don't even call this?
> Other question that comes to mind is that in case SDI is connected to CS, will
> all writes fail? Because if that's the case we other writes (like scale) that
> won't work and we should take care of that...

Definitely needs describing and all configuration sysfs etc needs to be read only
if we can't control it.

> 
> > +	return ad4000_write_reg(st, reg_val);
> > +}
> > +

Jonathan
Andy Shevchenko June 11, 2024, 10:34 a.m. UTC | #5
Sun, Jun 09, 2024 at 10:23:54AM +0100, Jonathan Cameron kirjoitti:

...

> > > +	/*
> > > +	 * In 4-wire mode, the CNV line is held high for the entire
> > > conversion
> > > +	 * and acquisition process. In other modes st->cnv_gpio is NULL and
> > > is
> > > +	 * ignored (CS is wired to CNV in those cases).
> > > +	 */
> > > +	gpiod_set_value_cansleep(st->cnv_gpio, 1);  
> > 
> > Not sure it's a good practise to assume internal details as you're going for
> > GPIO. I would prefer to have an explicit check for st->cnv_gpio being NULL or
> > not.
> 
> Hmm. I had it in my head that this was documented behaviour, but
> I can't find such in the docs, so agreed checking it makes sense.
> 
> I would be very surprised if this ever changed as it's one of the
> things that makes optional gpios easy to work with but who knows!

Not Linus and not Bart, but we have tons of drivers that call GPIO APIs
unconditionally as long as they want optional GPIO.

What I see here is the comment that should be rewritten to say something like

"if GPIO is defined blablabla, otherwise blablabla."

I.o.w. do not mention that implementation detail (being NULL, i.e. optional).
Jonathan Cameron June 11, 2024, 5:05 p.m. UTC | #6
On Tue, 11 Jun 2024 13:34:29 +0300
Andy Shevchenko <andy.shevchenko@gmail.com> wrote:

> Sun, Jun 09, 2024 at 10:23:54AM +0100, Jonathan Cameron kirjoitti:
> 
> ...
> 
> > > > +	/*
> > > > +	 * In 4-wire mode, the CNV line is held high for the entire
> > > > conversion
> > > > +	 * and acquisition process. In other modes st->cnv_gpio is NULL and
> > > > is
> > > > +	 * ignored (CS is wired to CNV in those cases).
> > > > +	 */
> > > > +	gpiod_set_value_cansleep(st->cnv_gpio, 1);    
> > > 
> > > Not sure it's a good practise to assume internal details as you're going for
> > > GPIO. I would prefer to have an explicit check for st->cnv_gpio being NULL or
> > > not.  
> > 
> > Hmm. I had it in my head that this was documented behaviour, but
> > I can't find such in the docs, so agreed checking it makes sense.
> > 
> > I would be very surprised if this ever changed as it's one of the
> > things that makes optional gpios easy to work with but who knows!  
> 
> Not Linus and not Bart, but we have tons of drivers that call GPIO APIs
> unconditionally as long as they want optional GPIO.
> 
> What I see here is the comment that should be rewritten to say something like
> 
> "if GPIO is defined blablabla, otherwise blablabla."
> 
> I.o.w. do not mention that implementation detail (being NULL, i.e. optional).
> 

Good point - handy comment there already and this minor tweak will make it clear.

Thanks Andy!

Jonathan
diff mbox series

Patch

diff --git a/MAINTAINERS b/MAINTAINERS
index 1f052b9cd912..c732cf13f511 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1206,6 +1206,7 @@  L:	linux-iio@vger.kernel.org
 S:	Supported
 W:	https://ez.analog.com/linux-software-drivers
 F:	Documentation/devicetree/bindings/iio/adc/adi,ad4000.yaml
+F:	drivers/iio/adc/ad4000.c
 
 ANALOG DEVICES INC AD4130 DRIVER
 M:	Cosmin Tanislav <cosmin.tanislav@analog.com>
diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index 5030319249c5..dcc49d9711a4 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -21,6 +21,18 @@  config AD_SIGMA_DELTA
 	select IIO_BUFFER
 	select IIO_TRIGGERED_BUFFER
 
+config AD4000
+	tristate "Analog Devices AD4000 ADC Driver"
+	depends on SPI
+	select IIO_BUFFER
+	select IIO_TRIGGERED_BUFFER
+	help
+	  Say yes here to build support for Analog Devices AD4000 high speed
+	  SPI analog to digital converters (ADC).
+
+	  To compile this driver as a module, choose M here: the module will be
+	  called ad4000.
+
 config AD4130
 	tristate "Analog Device AD4130 ADC Driver"
 	depends on SPI
diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
index 37ac689a0209..c32bd0ef6128 100644
--- a/drivers/iio/adc/Makefile
+++ b/drivers/iio/adc/Makefile
@@ -6,6 +6,7 @@ 
 # When adding new entries keep the list in alphabetical order
 obj-$(CONFIG_AB8500_GPADC) += ab8500-gpadc.o
 obj-$(CONFIG_AD_SIGMA_DELTA) += ad_sigma_delta.o
+obj-$(CONFIG_AD4000) += ad4000.o
 obj-$(CONFIG_AD4130) += ad4130.o
 obj-$(CONFIG_AD7091R) += ad7091r-base.o
 obj-$(CONFIG_AD7091R5) += ad7091r5.o
diff --git a/drivers/iio/adc/ad4000.c b/drivers/iio/adc/ad4000.c
new file mode 100644
index 000000000000..55dc36fbd549
--- /dev/null
+++ b/drivers/iio/adc/ad4000.c
@@ -0,0 +1,735 @@ 
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * AD4000 SPI ADC driver
+ *
+ * Copyright 2024 Analog Devices Inc.
+ */
+#include <asm/unaligned.h>
+#include <linux/bits.h>
+#include <linux/bitfield.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/kernel.h>
+#include <linux/math.h>
+#include <linux/module.h>
+#include <linux/mod_devicetable.h>
+#include <linux/gpio/consumer.h>
+#include <linux/regulator/consumer.h>
+#include <linux/spi/spi.h>
+#include <linux/sysfs.h>
+#include <linux/units.h>
+#include <linux/util_macros.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/triggered_buffer.h>
+#include <linux/iio/trigger_consumer.h>
+
+#define AD4000_READ_COMMAND	0x54
+#define AD4000_WRITE_COMMAND	0x14
+
+#define AD4000_CONFIG_REG_MSK	0xFF
+
+/* AD4000 Configuration Register programmable bits */
+#define AD4000_CFG_STATUS		BIT(4) /* Status bits output */
+#define AD4000_CFG_SPAN_COMP		BIT(3) /* Input span compression  */
+#define AD4000_CFG_HIGHZ		BIT(2) /* High impedance mode  */
+#define AD4000_CFG_TURBO		BIT(1) /* Turbo mode */
+
+#define AD4000_TQUIET1_NS		190
+#define AD4000_TQUIET2_NS		60
+#define AD4000_TCONV_NS			320
+
+#define AD4000_18BIT_MSK	GENMASK(31, 14)
+#define AD4000_20BIT_MSK	GENMASK(31, 12)
+
+#define AD4000_DIFF_CHANNEL(_sign, _real_bits)				\
+	{								\
+		.type = IIO_VOLTAGE,					\
+		.indexed = 1,						\
+		.differential = 1,					\
+		.channel = 0,						\
+		.channel2 = 1,						\
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |		\
+				      BIT(IIO_CHAN_INFO_SCALE),		\
+		.info_mask_separate_available = BIT(IIO_CHAN_INFO_SCALE),\
+		.scan_type = {						\
+			.sign = _sign,					\
+			.realbits = _real_bits,				\
+			.storagebits = _real_bits > 16 ? 32 : 16,	\
+			.shift = _real_bits > 16 ? 32 - _real_bits : 0,	\
+			.endianness = IIO_BE,				\
+		},							\
+	}								\
+
+#define AD4000_PSEUDO_DIFF_CHANNEL(_sign, _real_bits)			\
+	{								\
+		.type = IIO_VOLTAGE,					\
+		.indexed = 1,						\
+		.channel = 0,						\
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |		\
+				      BIT(IIO_CHAN_INFO_SCALE) |	\
+				      BIT(IIO_CHAN_INFO_OFFSET),	\
+		.info_mask_separate_available = BIT(IIO_CHAN_INFO_SCALE),\
+		.scan_type = {						\
+			.sign = _sign,					\
+			.realbits = _real_bits,				\
+			.storagebits = _real_bits > 16 ? 32 : 16,	\
+			.shift = _real_bits > 16 ? 32 - _real_bits : 0,	\
+			.endianness = IIO_BE,				\
+		},							\
+	}								\
+
+enum ad4000_ids {
+	ID_AD4000,
+	ID_AD4001,
+	ID_AD4002,
+	ID_AD4003,
+	ID_AD4004,
+	ID_AD4005,
+	ID_AD4006,
+	ID_AD4007,
+	ID_AD4008,
+	ID_AD4010,
+	ID_AD4011,
+	ID_AD4020,
+	ID_AD4021,
+	ID_AD4022,
+	ID_ADAQ4001,
+	ID_ADAQ4003,
+};
+
+enum ad4000_spi_mode {
+	/* datasheet calls this "4-wire mode" (controller CS goes to ADC SDI!) */
+	AD4000_SPI_MODE_DEFAULT,
+	/* datasheet calls this "3-wire mode" (not related to SPI_3WIRE!) */
+	AD4000_SPI_MODE_SINGLE,
+};
+
+/* maps adi,spi-mode property value to enum */
+static const char * const ad4000_spi_modes[] = {
+	[AD4000_SPI_MODE_DEFAULT] = "",
+	[AD4000_SPI_MODE_SINGLE] = "single",
+};
+
+struct ad4000_chip_info {
+	const char *dev_name;
+	struct iio_chan_spec chan_spec;
+};
+
+static const struct ad4000_chip_info ad4000_chips[] = {
+	[ID_AD4000] = {
+		.dev_name = "ad4000",
+		.chan_spec = AD4000_PSEUDO_DIFF_CHANNEL('u', 16),
+	},
+	[ID_AD4001] = {
+		.dev_name = "ad4001",
+		.chan_spec = AD4000_DIFF_CHANNEL('s', 16),
+	},
+	[ID_AD4002] = {
+		.dev_name = "ad4002",
+		.chan_spec = AD4000_PSEUDO_DIFF_CHANNEL('u', 18),
+	},
+	[ID_AD4003] = {
+		.dev_name = "ad4003",
+		.chan_spec = AD4000_DIFF_CHANNEL('s', 18),
+	},
+	[ID_AD4004] = {
+		.dev_name = "ad4004",
+		.chan_spec = AD4000_PSEUDO_DIFF_CHANNEL('u', 16),
+	},
+	[ID_AD4005] = {
+		.dev_name = "ad4005",
+		.chan_spec = AD4000_DIFF_CHANNEL('s', 16),
+	},
+	[ID_AD4006] = {
+		.dev_name = "ad4006",
+		.chan_spec = AD4000_PSEUDO_DIFF_CHANNEL('u', 18),
+	},
+	[ID_AD4007] = {
+		.dev_name = "ad4007",
+		.chan_spec = AD4000_DIFF_CHANNEL('s', 18),
+	},
+	[ID_AD4008] = {
+		.dev_name = "ad4008",
+		.chan_spec = AD4000_PSEUDO_DIFF_CHANNEL('u', 16),
+	},
+	[ID_AD4010] = {
+		.dev_name = "ad4010",
+		.chan_spec = AD4000_PSEUDO_DIFF_CHANNEL('u', 18),
+	},
+	[ID_AD4011] = {
+		.dev_name = "ad4011",
+		.chan_spec = AD4000_DIFF_CHANNEL('s', 18),
+	},
+	[ID_AD4020] = {
+		.dev_name = "ad4020",
+		.chan_spec = AD4000_DIFF_CHANNEL('s', 20),
+	},
+	[ID_AD4021] = {
+		.dev_name = "ad4021",
+		.chan_spec = AD4000_DIFF_CHANNEL('s', 20),
+	},
+	[ID_AD4022] = {
+		.dev_name = "ad4022",
+		.chan_spec = AD4000_DIFF_CHANNEL('s', 20),
+	},
+	[ID_ADAQ4001] = {
+		.dev_name = "adaq4001",
+		.chan_spec = AD4000_DIFF_CHANNEL('s', 16),
+	},
+	[ID_ADAQ4003] = {
+		.dev_name = "adaq4003",
+		.chan_spec = AD4000_DIFF_CHANNEL('s', 18),
+	},
+};
+
+struct ad4000_state {
+	struct spi_device *spi;
+	struct gpio_desc *cnv_gpio;
+	struct spi_transfer xfers[2];
+	struct spi_message msg;
+	int vref;
+	enum ad4000_spi_mode spi_mode;
+	bool span_comp;
+	bool turbo_mode;
+	int gain_milli;
+	int scale_tbl[2][2];
+
+	/*
+	 * DMA (thus cache coherency maintenance) requires the
+	 * transfer buffers to live in their own cache lines.
+	 */
+	struct {
+		union {
+			__be16 sample_buf16;
+			__be32 sample_buf32;
+		} data;
+		s64 timestamp __aligned(8);
+	} scan __aligned(IIO_DMA_MINALIGN);
+	__be16 tx_buf;
+	__be16 rx_buf;
+};
+
+static void ad4000_fill_scale_tbl(struct ad4000_state *st, int scale_bits,
+				  const struct ad4000_chip_info *chip)
+{
+	int diff = chip->chan_spec.differential;
+	int val, val2, tmp0, tmp1;
+	u64 tmp2;
+
+	val2 = scale_bits;
+	val = st->vref / 1000;
+	/*
+	 * The gain is stored as a fraction of 1000 and, as we need to
+	 * divide vref by gain, we invert the gain/1000 fraction.
+	 * Also multiply by an extra MILLI to avoid losing precision.
+	 */
+	val = mult_frac(val, MILLI * MILLI, st->gain_milli);
+	/* Would multiply by NANO here but we multiplied by extra MILLI */
+	tmp2 = shift_right((u64)val * MICRO, val2);
+	tmp0 = (int)div_s64_rem(tmp2, NANO, &tmp1);
+	/* Store scale for when span compression is disabled */
+	st->scale_tbl[0][0] = tmp0; /* Integer part */
+	st->scale_tbl[0][1] = abs(tmp1); /* Fractional part */
+	/* Store scale for when span compression is enabled */
+	st->scale_tbl[1][0] = tmp0;
+	/* The integer part is always zero so don't bother to divide it. */
+	if (diff)
+		st->scale_tbl[1][1] = DIV_ROUND_CLOSEST(abs(tmp1) * 4, 5);
+	else
+		st->scale_tbl[1][1] = DIV_ROUND_CLOSEST(abs(tmp1) * 9, 10);
+}
+
+static int ad4000_write_reg(struct ad4000_state *st, uint8_t val)
+{
+	st->tx_buf = cpu_to_be16(AD4000_WRITE_COMMAND << BITS_PER_BYTE | val);
+	return spi_write(st->spi, &st->tx_buf, 2);
+}
+
+static int ad4000_read_reg(struct ad4000_state *st, unsigned int *val)
+{
+	struct spi_transfer t[] = {
+		{
+			.tx_buf = &st->tx_buf,
+			.rx_buf = &st->rx_buf,
+			.len = 2,
+		},
+	};
+	int ret;
+
+	st->tx_buf = cpu_to_be16(AD4000_READ_COMMAND << BITS_PER_BYTE);
+	ret = spi_sync_transfer(st->spi, t, ARRAY_SIZE(t));
+	if (ret < 0)
+		return ret;
+
+	*val = be16_to_cpu(st->rx_buf);
+
+	return ret;
+}
+
+static void ad4000_unoptimize_msg(void *msg)
+{
+	spi_unoptimize_message(msg);
+}
+
+/*
+ * This executes a data sample transfer for when the device connections are
+ * in "3-wire" mode, selected by setting the adi,spi-mode device tree property
+ * to "single". In this connection mode, the ADC SDI pin is connected to MOSI or
+ * to VIO and ADC CNV pin is connected either to a SPI controller CS or to a GPIO.
+ * AD4000 series of devices initiate conversions on the rising edge of CNV pin.
+ *
+ * If the CNV pin is connected to an SPI controller CS line (which is by default
+ * active low), the ADC readings would have a latency (delay) of one read.
+ * Moreover, since we also do ADC sampling for filling the buffer on triggered
+ * buffer mode, the timestamps of buffer readings would be disarranged.
+ * To prevent the read latency and reduce the time discrepancy between the
+ * sample read request and the time of actual sampling by the ADC, do a
+ * preparatory transfer to pulse the CS/CNV line.
+ */
+static int ad4000_prepare_3wire_mode_message(struct ad4000_state *st,
+					     const struct iio_chan_spec *chan)
+{
+	unsigned int cnv_pulse_time = st->turbo_mode ? AD4000_TQUIET1_NS
+						     : AD4000_TCONV_NS;
+	struct spi_transfer *xfers = st->xfers;
+	int ret;
+
+	xfers[0].cs_change = 1;
+	xfers[0].cs_change_delay.value = cnv_pulse_time;
+	xfers[0].cs_change_delay.unit = SPI_DELAY_UNIT_NSECS;
+
+	xfers[1].rx_buf = &st->scan.data;
+	xfers[1].len = BITS_TO_BYTES(chan->scan_type.storagebits);
+	xfers[1].delay.value = AD4000_TQUIET2_NS;
+	xfers[1].delay.unit = SPI_DELAY_UNIT_NSECS;
+
+	spi_message_init_with_transfers(&st->msg, st->xfers, 2);
+
+	ret = spi_optimize_message(st->spi, &st->msg);
+	if (ret)
+		return ret;
+
+	return devm_add_action_or_reset(&st->spi->dev, ad4000_unoptimize_msg,
+					&st->msg);
+}
+
+/*
+ * This executes a data sample transfer for when the device connections are
+ * in "4-wire" mode, selected when the adi,spi-mode device tree
+ * property is absent or empty. In this connection mode, the controller CS pin
+ * is connected to ADC SDI pin and a GPIO is connected to ADC CNV pin.
+ * The GPIO connected to ADC CNV pin is set outside of the SPI transfer.
+ */
+static int ad4000_prepare_4wire_mode_message(struct ad4000_state *st,
+					     const struct iio_chan_spec *chan)
+{
+	unsigned int cnv_to_sdi_time = st->turbo_mode ? AD4000_TQUIET1_NS
+						      : AD4000_TCONV_NS;
+	struct spi_transfer *xfers = st->xfers;
+	int ret;
+
+	/*
+	 * Dummy transfer to cause enough delay between CNV going high and SDI
+	 * going low.
+	 */
+	xfers[0].cs_off = 1;
+	xfers[0].delay.value = cnv_to_sdi_time;
+	xfers[0].delay.unit = SPI_DELAY_UNIT_NSECS;
+
+	xfers[1].rx_buf = &st->scan.data;
+	xfers[1].len = BITS_TO_BYTES(chan->scan_type.storagebits);
+
+	spi_message_init_with_transfers(&st->msg, st->xfers, 2);
+
+	ret = spi_optimize_message(st->spi, &st->msg);
+	if (ret)
+		return ret;
+
+	return devm_add_action_or_reset(&st->spi->dev, ad4000_unoptimize_msg,
+					&st->msg);
+}
+
+static int ad4000_convert_and_acquire(struct ad4000_state *st)
+{
+	int ret;
+
+	/*
+	 * In 4-wire mode, the CNV line is held high for the entire conversion
+	 * and acquisition process. In other modes st->cnv_gpio is NULL and is
+	 * ignored (CS is wired to CNV in those cases).
+	 */
+	gpiod_set_value_cansleep(st->cnv_gpio, 1);
+	ret = spi_sync(st->spi, &st->msg);
+	gpiod_set_value_cansleep(st->cnv_gpio, 0);
+
+	return ret;
+}
+
+static int ad4000_single_conversion(struct iio_dev *indio_dev,
+				    const struct iio_chan_spec *chan, int *val)
+{
+	struct ad4000_state *st = iio_priv(indio_dev);
+	u32 sample;
+	int ret;
+
+	ret = ad4000_convert_and_acquire(st);
+
+	if (chan->scan_type.storagebits > 16)
+		sample = be32_to_cpu(st->scan.data.sample_buf32);
+	else
+		sample = be16_to_cpu(st->scan.data.sample_buf16);
+
+	switch (chan->scan_type.realbits) {
+	case 16:
+		break;
+	case 18:
+		sample = FIELD_GET(AD4000_18BIT_MSK, sample);
+		break;
+	case 20:
+		sample = FIELD_GET(AD4000_20BIT_MSK, sample);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	if (chan->scan_type.sign == 's')
+		*val = sign_extend32(sample, chan->scan_type.realbits - 1);
+
+	return IIO_VAL_INT;
+}
+
+static int ad4000_read_raw(struct iio_dev *indio_dev,
+			   struct iio_chan_spec const *chan, int *val,
+			   int *val2, long info)
+{
+	struct ad4000_state *st = iio_priv(indio_dev);
+
+	switch (info) {
+	case IIO_CHAN_INFO_RAW:
+		iio_device_claim_direct_scoped(return -EBUSY, indio_dev)
+			return ad4000_single_conversion(indio_dev, chan, val);
+		unreachable();
+	case IIO_CHAN_INFO_SCALE:
+		*val = st->scale_tbl[st->span_comp][0];
+		*val2 = st->scale_tbl[st->span_comp][1];
+		return IIO_VAL_INT_PLUS_NANO;
+	case IIO_CHAN_INFO_OFFSET:
+		*val = 0;
+		if (st->span_comp)
+			*val = mult_frac(st->vref / 1000, 1, 10);
+
+		return IIO_VAL_INT;
+	default:
+		return -EINVAL;
+	}
+}
+
+static int ad4000_read_avail(struct iio_dev *indio_dev,
+			     struct iio_chan_spec const *chan,
+			     const int **vals, int *type, int *length,
+			     long info)
+{
+	struct ad4000_state *st = iio_priv(indio_dev);
+
+	switch (info) {
+	case IIO_CHAN_INFO_SCALE:
+		*vals = (int *)st->scale_tbl;
+		*length = 2 * 2;
+		*type = IIO_VAL_INT_PLUS_NANO;
+		return IIO_AVAIL_LIST;
+	default:
+		return -EINVAL;
+	}
+}
+
+static int ad4000_write_raw_get_fmt(struct iio_dev *indio_dev,
+				    struct iio_chan_spec const *chan, long mask)
+{
+	switch (mask) {
+	case IIO_CHAN_INFO_SCALE:
+		return IIO_VAL_INT_PLUS_NANO;
+	default:
+		return IIO_VAL_INT_PLUS_MICRO;
+	}
+}
+
+static int ad4000_write_raw(struct iio_dev *indio_dev,
+			    struct iio_chan_spec const *chan, int val, int val2,
+			    long mask)
+{
+	struct ad4000_state *st = iio_priv(indio_dev);
+	unsigned int reg_val;
+	bool span_comp_en;
+	int ret;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_SCALE:
+		iio_device_claim_direct_scoped(return -EBUSY, indio_dev) {
+			ret = ad4000_read_reg(st, &reg_val);
+			if (ret < 0)
+				return ret;
+
+			span_comp_en = (val2 == st->scale_tbl[1][1]);
+			reg_val &= ~AD4000_CFG_SPAN_COMP;
+			reg_val |= FIELD_PREP(AD4000_CFG_SPAN_COMP, span_comp_en);
+
+			ret = ad4000_write_reg(st, reg_val);
+			if (ret < 0)
+				return ret;
+
+			st->span_comp = span_comp_en;
+			return 0;
+		}
+		unreachable();
+	default:
+		return -EINVAL;
+	}
+}
+
+static irqreturn_t ad4000_trigger_handler(int irq, void *p)
+{
+	struct iio_poll_func *pf = p;
+	struct iio_dev *indio_dev = pf->indio_dev;
+	struct ad4000_state *st = iio_priv(indio_dev);
+	int ret;
+
+	ret = ad4000_convert_and_acquire(st);
+	if (ret < 0)
+		goto err_out;
+
+	iio_push_to_buffers_with_timestamp(indio_dev, &st->scan,
+					   iio_get_time_ns(indio_dev));
+
+err_out:
+	iio_trigger_notify_done(indio_dev->trig);
+	return IRQ_HANDLED;
+}
+
+static int ad4000_reg_access(struct iio_dev *indio_dev, unsigned int reg,
+			     unsigned int writeval, unsigned int *readval)
+{
+	struct ad4000_state *st = iio_priv(indio_dev);
+	int ret;
+
+	if (readval)
+		ret = ad4000_read_reg(st, readval);
+	else
+		ret = ad4000_write_reg(st, writeval);
+
+	return ret;
+}
+
+static const struct iio_info ad4000_info = {
+	.read_raw = &ad4000_read_raw,
+	.read_avail = &ad4000_read_avail,
+	.write_raw = &ad4000_write_raw,
+	.write_raw_get_fmt = &ad4000_write_raw_get_fmt,
+	.debugfs_reg_access = &ad4000_reg_access,
+
+};
+
+static int ad4000_config(struct ad4000_state *st)
+{
+	unsigned int reg_val;
+
+	if (device_property_present(&st->spi->dev, "adi,high-z-input"))
+		reg_val |= FIELD_PREP(AD4000_CFG_HIGHZ, 1);
+
+	/*
+	 * The ADC SDI pin might be connected to controller CS line in which
+	 * case the write might fail. This, however, does not prevent the device
+	 * from functioning even though in a configuration other than the
+	 * requested one.
+	 */
+	return ad4000_write_reg(st, reg_val);
+}
+
+static void ad4000_regulator_disable(void *reg)
+{
+	regulator_disable(reg);
+}
+
+static int ad4000_probe(struct spi_device *spi)
+{
+	const struct ad4000_chip_info *chip;
+	struct regulator *vref_reg;
+	struct iio_dev *indio_dev;
+	struct ad4000_state *st;
+	int ret;
+
+	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	chip = spi_get_device_match_data(spi);
+	if (!chip)
+		return -EINVAL;
+
+	st = iio_priv(indio_dev);
+	st->spi = spi;
+
+	ret = devm_regulator_get_enable(&spi->dev, "vdd");
+	if (ret)
+		return dev_err_probe(&spi->dev, ret, "Failed to enable VDD supply\n");
+
+	ret = devm_regulator_get_enable(&spi->dev, "vio");
+	if (ret)
+		return dev_err_probe(&spi->dev, ret, "Failed to enable VIO supply\n");
+
+	vref_reg = devm_regulator_get(&spi->dev, "ref");
+	if (IS_ERR(vref_reg))
+		return dev_err_probe(&spi->dev, PTR_ERR(vref_reg),
+				     "Failed to get vref regulator\n");
+
+	ret = regulator_enable(vref_reg);
+	if (ret < 0)
+		return dev_err_probe(&spi->dev, ret,
+				     "Failed to enable voltage regulator\n");
+
+	ret = devm_add_action_or_reset(&spi->dev, ad4000_regulator_disable, vref_reg);
+	if (ret)
+		return dev_err_probe(&spi->dev, ret,
+				     "Failed to add regulator disable action\n");
+
+	st->vref = regulator_get_voltage(vref_reg);
+	if (st->vref < 0)
+		return dev_err_probe(&spi->dev, st->vref, "Failed to get vref\n");
+
+	st->cnv_gpio = devm_gpiod_get_optional(&spi->dev, "cnv", GPIOD_OUT_HIGH);
+	if (IS_ERR(st->cnv_gpio))
+		return dev_err_probe(&spi->dev, PTR_ERR(st->cnv_gpio),
+				     "Failed to get CNV GPIO");
+
+	ret = device_property_match_property_string(&spi->dev, "adi,spi-mode",
+						    ad4000_spi_modes,
+						    ARRAY_SIZE(ad4000_spi_modes));
+	/* Default to 4-wire mode if adi,spi-mode property is not present */
+	if (ret == -EINVAL)
+		st->spi_mode = AD4000_SPI_MODE_DEFAULT;
+	else if (ret < 0)
+		return dev_err_probe(&spi->dev, ret,
+				     "getting adi,spi-mode property failed\n");
+	else
+		st->spi_mode = ret;
+
+	switch (st->spi_mode) {
+	case AD4000_SPI_MODE_DEFAULT:
+		ret = ad4000_prepare_4wire_mode_message(st, &chip->chan_spec);
+		if (ret)
+			return ret;
+
+		break;
+	case AD4000_SPI_MODE_SINGLE:
+		ret = ad4000_prepare_3wire_mode_message(st, &chip->chan_spec);
+		if (ret)
+			return ret;
+
+		/*
+		 * In "3-wire mode", the ADC SDI line must be kept high when
+		 * data is not being clocked out of the controller.
+		 * Request the SPI controller to make MOSI idle high.
+		 */
+		spi->mode = SPI_MODE_0 | SPI_MOSI_IDLE_HIGH;
+		if (spi_setup(spi))
+			dev_warn(&st->spi->dev, "SPI controller setup failed\n");
+
+		break;
+	}
+
+	ret = ad4000_config(st);
+	if (ret < 0)
+		dev_dbg(&st->spi->dev, "Failed to config device\n");
+
+	indio_dev->name = chip->dev_name;
+	indio_dev->info = &ad4000_info;
+	indio_dev->channels = &chip->chan_spec;
+	indio_dev->num_channels = 1;
+
+	/* Hardware gain only applies to ADAQ devices */
+	st->gain_milli = 1000;
+	if (device_property_present(&spi->dev, "adi,gain-milli")) {
+
+		ret = device_property_read_u32(&spi->dev, "adi,gain-milli",
+					       &st->gain_milli);
+		if (ret)
+			return dev_err_probe(&spi->dev, ret,
+					     "Failed to read gain property\n");
+	}
+
+	/*
+	 * ADCs that output two's complement code have one less bit to express
+	 * voltage magnitude.
+	 */
+	if (chip->chan_spec.scan_type.sign == 's')
+		ad4000_fill_scale_tbl(st, chip->chan_spec.scan_type.realbits - 1,
+				      chip);
+	else
+		ad4000_fill_scale_tbl(st, chip->chan_spec.scan_type.realbits,
+				      chip);
+
+	ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev,
+					      &iio_pollfunc_store_time,
+					      &ad4000_trigger_handler, NULL);
+	if (ret)
+		return ret;
+
+	return devm_iio_device_register(&spi->dev, indio_dev);
+}
+
+static const struct spi_device_id ad4000_id[] = {
+	{ "ad4000", (kernel_ulong_t)&ad4000_chips[ID_AD4000] },
+	{ "ad4001", (kernel_ulong_t)&ad4000_chips[ID_AD4001] },
+	{ "ad4002", (kernel_ulong_t)&ad4000_chips[ID_AD4002] },
+	{ "ad4003", (kernel_ulong_t)&ad4000_chips[ID_AD4003] },
+	{ "ad4004", (kernel_ulong_t)&ad4000_chips[ID_AD4004] },
+	{ "ad4005", (kernel_ulong_t)&ad4000_chips[ID_AD4005] },
+	{ "ad4006", (kernel_ulong_t)&ad4000_chips[ID_AD4006] },
+	{ "ad4007", (kernel_ulong_t)&ad4000_chips[ID_AD4007] },
+	{ "ad4008", (kernel_ulong_t)&ad4000_chips[ID_AD4008] },
+	{ "ad4010", (kernel_ulong_t)&ad4000_chips[ID_AD4010] },
+	{ "ad4011", (kernel_ulong_t)&ad4000_chips[ID_AD4011] },
+	{ "ad4020", (kernel_ulong_t)&ad4000_chips[ID_AD4020] },
+	{ "ad4021", (kernel_ulong_t)&ad4000_chips[ID_AD4021] },
+	{ "ad4022", (kernel_ulong_t)&ad4000_chips[ID_AD4022] },
+	{ "adaq4001", (kernel_ulong_t)&ad4000_chips[ID_ADAQ4001] },
+	{ "adaq4003", (kernel_ulong_t)&ad4000_chips[ID_ADAQ4003] },
+	{ }
+};
+MODULE_DEVICE_TABLE(spi, ad4000_id);
+
+static const struct of_device_id ad4000_of_match[] = {
+	{ .compatible = "adi,ad4000", .data = &ad4000_chips[ID_AD4000] },
+	{ .compatible = "adi,ad4001", .data = &ad4000_chips[ID_AD4001] },
+	{ .compatible = "adi,ad4002", .data = &ad4000_chips[ID_AD4002] },
+	{ .compatible = "adi,ad4003", .data = &ad4000_chips[ID_AD4003] },
+	{ .compatible = "adi,ad4004", .data = &ad4000_chips[ID_AD4004] },
+	{ .compatible = "adi,ad4005", .data = &ad4000_chips[ID_AD4005] },
+	{ .compatible = "adi,ad4006", .data = &ad4000_chips[ID_AD4006] },
+	{ .compatible = "adi,ad4007", .data = &ad4000_chips[ID_AD4007] },
+	{ .compatible = "adi,ad4008", .data = &ad4000_chips[ID_AD4008] },
+	{ .compatible = "adi,ad4010", .data = &ad4000_chips[ID_AD4010] },
+	{ .compatible = "adi,ad4011", .data = &ad4000_chips[ID_AD4011] },
+	{ .compatible = "adi,ad4020", .data = &ad4000_chips[ID_AD4020] },
+	{ .compatible = "adi,ad4021", .data = &ad4000_chips[ID_AD4021] },
+	{ .compatible = "adi,ad4022", .data = &ad4000_chips[ID_AD4022] },
+	{ .compatible = "adi,adaq4001", .data = &ad4000_chips[ID_ADAQ4001] },
+	{ .compatible = "adi,adaq4003", .data = &ad4000_chips[ID_ADAQ4003] },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, ad4000_of_match);
+
+static struct spi_driver ad4000_driver = {
+	.driver = {
+		.name   = "ad4000",
+		.of_match_table = ad4000_of_match,
+	},
+	.probe          = ad4000_probe,
+	.id_table       = ad4000_id,
+};
+module_spi_driver(ad4000_driver);
+
+MODULE_AUTHOR("Marcelo Schmitt <marcelo.schmitt@analog.com>");
+MODULE_DESCRIPTION("Analog Devices AD4000 ADC driver");
+MODULE_LICENSE("GPL");