Commit 2920b6ee authored by David Lechner's avatar David Lechner Committed by Jonathan Cameron
Browse files

iio: adc: ad7380: add support for pseudo-differential parts 



Add support for AD7383, AD7384 pseudo-differential compatible parts.
Pseudo differential parts require common mode voltage supplies so add
the support for them and add the support of IIO_CHAN_INFO_OFFSET to
retrieve the offset

Signed-off-by: default avatarDavid Lechner <dlechner@baylibre.com>
Signed-off-by: default avatarJulien Stephan <jstephan@baylibre.com>
Link: https://lore.kernel.org/r/20240528-adding-new-ad738x-driver-v7-4-4cd70a4c12c8@baylibre.com


Signed-off-by: default avatarJonathan Cameron <Jonathan.Cameron@huawei.com>
parent 6b2c8019

drivers/iio/adc/ad7380.c

+94 −16
Original line number Diff line number Diff line
@@ -7,6 +7,7 @@ 
 *

 * Datasheets of supported parts:

 * ad7380/1 : https://www.analog.com/media/en/technical-documentation/data-sheets/AD7380-7381.pdf

 * ad7383/4 : https://www.analog.com/media/en/technical-documentation/data-sheets/ad7383-7384.pdf

 */



#include <linux/bitfield.h>
@@ -66,16 +67,19 @@ struct ad7380_chip_info { 
	const char *name;

	const struct iio_chan_spec *channels;

	unsigned int num_channels;

	const char * const *vcm_supplies;

	unsigned int num_vcm_supplies;

};



#define AD7380_CHANNEL(index, bits) {				\

#define AD7380_CHANNEL(index, bits, diff) {			\

	.type = IIO_VOLTAGE,					\

	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),		\

	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |		\

		((diff) ? 0 : BIT(IIO_CHAN_INFO_OFFSET)),	\

	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),	\

	.indexed = 1,						\

	.differential = 1,					\

	.channel = 2 * (index),					\

	.channel2 = 2 * (index) + 1,				\

	.differential = (diff),					\

	.channel = (diff) ? (2 * (index)) : (index),		\

	.channel2 = (diff) ? (2 * (index) + 1) : 0,		\

	.scan_index = (index),					\

	.scan_type = {						\

		.sign = 's',					\
@@ -85,15 +89,23 @@ struct ad7380_chip_info { 
	},							\

}



#define DEFINE_AD7380_2_CHANNEL(name, bits)	\

#define DEFINE_AD7380_2_CHANNEL(name, bits, diff)	\

static const struct iio_chan_spec name[] = {		\

	AD7380_CHANNEL(0, bits),		\

	AD7380_CHANNEL(1, bits),		\

	AD7380_CHANNEL(0, bits, diff),			\

	AD7380_CHANNEL(1, bits, diff),			\

	IIO_CHAN_SOFT_TIMESTAMP(2),			\

}



DEFINE_AD7380_2_CHANNEL(ad7380_channels, 16);

DEFINE_AD7380_2_CHANNEL(ad7381_channels, 14);

/* fully differential */

DEFINE_AD7380_2_CHANNEL(ad7380_channels, 16, 1);

DEFINE_AD7380_2_CHANNEL(ad7381_channels, 14, 1);

/* pseudo differential */

DEFINE_AD7380_2_CHANNEL(ad7383_channels, 16, 0);

DEFINE_AD7380_2_CHANNEL(ad7384_channels, 14, 0);



static const char * const ad7380_2_channel_vcm_supplies[] = {

	"aina", "ainb",

};



/* Since this is simultaneous sampling, we don't allow individual channels. */

static const unsigned long ad7380_2_channel_scan_masks[] = {
@@ -113,11 +125,28 @@ static const struct ad7380_chip_info ad7381_chip_info = { 
	.num_channels = ARRAY_SIZE(ad7381_channels),

};



static const struct ad7380_chip_info ad7383_chip_info = {

	.name = "ad7383",

	.channels = ad7383_channels,

	.num_channels = ARRAY_SIZE(ad7383_channels),

	.vcm_supplies = ad7380_2_channel_vcm_supplies,

	.num_vcm_supplies = ARRAY_SIZE(ad7380_2_channel_vcm_supplies),

};



static const struct ad7380_chip_info ad7384_chip_info = {

	.name = "ad7384",

	.channels = ad7384_channels,

	.num_channels = ARRAY_SIZE(ad7384_channels),

	.vcm_supplies = ad7380_2_channel_vcm_supplies,

	.num_vcm_supplies = ARRAY_SIZE(ad7380_2_channel_vcm_supplies),

};



struct ad7380_state {

	const struct ad7380_chip_info *chip_info;

	struct spi_device *spi;

	struct regmap *regmap;

	unsigned int vref_mv;

	unsigned int vcm_mv[2];

	/*

	 * DMA (thus cache coherency maintenance) requires the

	 * transfer buffers to live in their own cache lines.
@@ -288,13 +317,24 @@ static int ad7380_read_raw(struct iio_dev *indio_dev, 
		unreachable();

	case IIO_CHAN_INFO_SCALE:

		/*

		 * According to the datasheet, the LSB size for fully differential ADC is

		 * (2 × VREF) / 2^N, where N is the ADC resolution (i.e realbits)

		 * According to the datasheet, the LSB size is:

		 *    * (2 × VREF) / 2^N, for differential chips

		 *    * VREF / 2^N, for pseudo-differential chips

		 * where N is the ADC resolution (i.e realbits)

		 */

		*val = st->vref_mv;

		*val2 = chan->scan_type.realbits - 1;

		*val2 = chan->scan_type.realbits - chan->differential;



		return IIO_VAL_FRACTIONAL_LOG2;

	case IIO_CHAN_INFO_OFFSET:

		/*

		 * According to IIO ABI, offset is applied before scale,

		 * so offset is: vcm_mv / scale

		 */

		*val = st->vcm_mv[chan->channel] * (1 << chan->scan_type.realbits)

			/ st->vref_mv;



		return IIO_VAL_INT;

	default:

		return -EINVAL;

	}
@@ -341,7 +381,7 @@ static int ad7380_probe(struct spi_device *spi) 
	struct iio_dev *indio_dev;

	struct ad7380_state *st;

	struct regulator *vref;

	int ret;

	int ret, i;



	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));

	if (!indio_dev)
@@ -385,6 +425,40 @@ static int ad7380_probe(struct spi_device *spi) 
		st->vref_mv = AD7380_INTERNAL_REF_MV;

	}



	if (st->chip_info->num_vcm_supplies > ARRAY_SIZE(st->vcm_mv))

		return dev_err_probe(&spi->dev, -EINVAL,

				     "invalid number of VCM supplies\n");



	/*

	 * pseudo-differential chips have common mode supplies for the negative

	 * input pin.

	 */

	for (i = 0; i < st->chip_info->num_vcm_supplies; i++) {

		struct regulator *vcm;



		vcm = devm_regulator_get(&spi->dev,

					 st->chip_info->vcm_supplies[i]);

		if (IS_ERR(vcm))

			return dev_err_probe(&spi->dev, PTR_ERR(vcm),

					     "Failed to get %s regulator\n",

					     st->chip_info->vcm_supplies[i]);



		ret = regulator_enable(vcm);

		if (ret)

			return ret;



		ret = devm_add_action_or_reset(&spi->dev,

					       ad7380_regulator_disable, vcm);

		if (ret)

			return ret;



		ret = regulator_get_voltage(vcm);

		if (ret < 0)

			return ret;



		st->vcm_mv[i] = ret / 1000;

	}



	st->regmap = devm_regmap_init(&spi->dev, NULL, st, &ad7380_regmap_config);

	if (IS_ERR(st->regmap))

		return dev_err_probe(&spi->dev, PTR_ERR(st->regmap),
@@ -413,12 +487,16 @@ static int ad7380_probe(struct spi_device *spi) 
static const struct of_device_id ad7380_of_match_table[] = {

	{ .compatible = "adi,ad7380", .data = &ad7380_chip_info },

	{ .compatible = "adi,ad7381", .data = &ad7381_chip_info },

	{ .compatible = "adi,ad7383", .data = &ad7383_chip_info },

	{ .compatible = "adi,ad7384", .data = &ad7384_chip_info },

	{ }

};



static const struct spi_device_id ad7380_id_table[] = {

	{ "ad7380", (kernel_ulong_t)&ad7380_chip_info },

	{ "ad7381", (kernel_ulong_t)&ad7381_chip_info },

	{ "ad7383", (kernel_ulong_t)&ad7383_chip_info },

	{ "ad7384", (kernel_ulong_t)&ad7384_chip_info },

	{ }

};

MODULE_DEVICE_TABLE(spi, ad7380_id_table);