iio: adc: Add support for AD4170 series of ADCs

1,552 lines not on this page · raw message

index 58716ad6e7fc..7b85771ff0d1 100644
@@ -628,6 +628,7 @@ static const struct iio_chan_spec ad4170_channel_template = {
 	.differential = 1,
 	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
 			      BIT(IIO_CHAN_INFO_SCALE) |
+			      BIT(IIO_CHAN_INFO_CALIBSCALE) |
 			      BIT(IIO_CHAN_INFO_OFFSET),
 	.info_mask_separate_available = BIT(IIO_CHAN_INFO_SCALE),
 	.scan_type = {

@@ -945,6 +946,9 @@ static int ad4170_read_raw(struct iio_dev *indio_dev,
 		pga = FIELD_GET(AD4170_AFE_PGA_GAIN_MSK, setup->afe);
 		*val = chan_info->offset_tbl[pga];
 		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_CALIBSCALE:
+		*val = setup->gain;
+		return IIO_VAL_INT;
 	default:
 		return -EINVAL;
 	}

@@ -1059,6 +1063,18 @@ static int ad4170_set_pga(struct ad4170_state *st,
 	return ad4170_write_channel_setup(st, chan->address, false);
 }
 
+static int ad4170_set_calib_gain(struct ad4170_state *st,
+				 struct iio_chan_spec const *chan, int val)
+{
+	struct ad4170_chan_info *chan_info = &st->chan_infos[chan->address];
+	struct ad4170_setup *setup = &chan_info->setup;
+
+	guard(mutex)(&st->lock);
+	setup->gain = val;
+
+	return ad4170_write_channel_setup(st, chan->address, false);
+}
+
 static int __ad4170_write_raw(struct iio_dev *indio_dev,
 			      struct iio_chan_spec const *chan, int val,
 			      int val2, long info)

@@ -1068,6 +1084,8 @@ static int __ad4170_write_raw(struct iio_dev *indio_dev,
 	switch (info) {
 	case IIO_CHAN_INFO_SCALE:
 		return ad4170_set_pga(st, chan, val, val2);
+	case IIO_CHAN_INFO_CALIBSCALE:
+		return ad4170_set_calib_gain(st, chan, val);
 	default:
 		return -EINVAL;
 	}

@@ -1094,6 +1112,8 @@ static int ad4170_write_raw_get_fmt(struct iio_dev *indio_dev,
 	switch (info) {
 	case IIO_CHAN_INFO_SCALE:
 		return IIO_VAL_INT_PLUS_NANO;
+	case IIO_CHAN_INFO_CALIBSCALE:
+		return IIO_VAL_INT;
 	default:
 		return -EINVAL;
 	}

index 7b85771ff0d1..5c442af51f76 100644
@@ -628,6 +628,7 @@ static const struct iio_chan_spec ad4170_channel_template = {
 	.differential = 1,
 	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
 			      BIT(IIO_CHAN_INFO_SCALE) |
+			      BIT(IIO_CHAN_INFO_CALIBBIAS) |
 			      BIT(IIO_CHAN_INFO_CALIBSCALE) |
 			      BIT(IIO_CHAN_INFO_OFFSET),
 	.info_mask_separate_available = BIT(IIO_CHAN_INFO_SCALE),

@@ -946,6 +947,9 @@ static int ad4170_read_raw(struct iio_dev *indio_dev,
 		pga = FIELD_GET(AD4170_AFE_PGA_GAIN_MSK, setup->afe);
 		*val = chan_info->offset_tbl[pga];
 		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_CALIBBIAS:
+		*val = setup->offset;
+		return IIO_VAL_INT;
 	case IIO_CHAN_INFO_CALIBSCALE:
 		*val = setup->gain;
 		return IIO_VAL_INT;

@@ -1063,6 +1067,18 @@ static int ad4170_set_pga(struct ad4170_state *st,
 	return ad4170_write_channel_setup(st, chan->address, false);
 }
 
+static int ad4170_set_calib_offset(struct ad4170_state *st,
+				   struct iio_chan_spec const *chan, int val)
+{
+	struct ad4170_chan_info *chan_info = &st->chan_infos[chan->address];
+	struct ad4170_setup *setup = &chan_info->setup;
+
+	guard(mutex)(&st->lock);
+	setup->offset = val;
+
+	return ad4170_write_channel_setup(st, chan->address, false);
+}
+
 static int ad4170_set_calib_gain(struct ad4170_state *st,
 				 struct iio_chan_spec const *chan, int val)
 {

@@ -1084,6 +1100,8 @@ static int __ad4170_write_raw(struct iio_dev *indio_dev,
 	switch (info) {
 	case IIO_CHAN_INFO_SCALE:
 		return ad4170_set_pga(st, chan, val, val2);
+	case IIO_CHAN_INFO_CALIBBIAS:
+		return ad4170_set_calib_offset(st, chan, val);
 	case IIO_CHAN_INFO_CALIBSCALE:
 		return ad4170_set_calib_gain(st, chan, val);
 	default:

@@ -1112,6 +1130,7 @@ static int ad4170_write_raw_get_fmt(struct iio_dev *indio_dev,
 	switch (info) {
 	case IIO_CHAN_INFO_SCALE:
 		return IIO_VAL_INT_PLUS_NANO;
+	case IIO_CHAN_INFO_CALIBBIAS:
 	case IIO_CHAN_INFO_CALIBSCALE:
 		return IIO_VAL_INT;
 	default:

index 5c442af51f76..b229a24b40de 100644
@@ -18,6 +18,7 @@
 #include <linux/interrupt.h>
 #include <linux/irq.h>
 #include <linux/math64.h>
+#include <linux/minmax.h>
 #include <linux/module.h>
 #include <linux/property.h>
 #include <linux/regmap.h>

@@ -88,6 +89,9 @@
 #define AD4170_AFE_BIPOLAR_MSK				BIT(4)
 #define AD4170_AFE_PGA_GAIN_MSK				GENMASK(3, 0)
 
+/* AD4170_FILTER_REG */
+#define AD4170_FILTER_FILTER_TYPE_MSK			GENMASK(3, 0)
+
 /* AD4170 register constants */
 
 /* AD4170_CHAN_MAP_REG constants */

@@ -113,6 +117,11 @@
 #define AD4170_ADC_CTRL_MODE_SINGLE			0x4
 #define AD4170_ADC_CTRL_MODE_IDLE			0x7
 
+/* AD4170_FILTER_REG constants */
+#define AD4170_FILTER_FILTER_TYPE_SINC5_AVG		0x0
+#define AD4170_FILTER_FILTER_TYPE_SINC5			0x4
+#define AD4170_FILTER_FILTER_TYPE_SINC3			0x6
+
 /* Device properties and auxiliary constants */
 
 #define AD4170_NUM_ANALOG_PINS				9

@@ -122,6 +131,7 @@
 #define AD4170_INVALID_SETUP				9
 #define AD4170_SPI_INST_PHASE_LEN			2
 #define AD4170_SPI_MAX_XFER_LEN				6
+#define AD4170_DEFAULT_SAMP_RATE			(125 * HZ_PER_KHZ)
 
 #define AD4170_INT_REF_2_5V				2500000
 

@@ -130,6 +140,12 @@
 
 #define AD4170_NUM_PGA_OPTIONS				10
 
+/* Digital filter properties */
+#define AD4170_SINC3_MIN_FS				4
+#define AD4170_SINC3_MAX_FS				65532
+#define AD4170_SINC5_MIN_FS				1
+#define AD4170_SINC5_MAX_FS				256
+
 #define AD4170_GAIN_REG_DEFAULT				0x555555
 
 static const unsigned int ad4170_reg_size[] = {

@@ -190,6 +206,12 @@ enum ad4170_ref_select {
 	AD4170_REF_AVDD,
 };
 
+enum ad4170_filter_type {
+	AD4170_SINC5_AVG,
+	AD4170_SINC5,
+	AD4170_SINC3,
+};
+
 enum ad4170_regulator {
 	AD4170_AVDD_SUP,
 	AD4170_AVSS_SUP,

@@ -211,6 +233,18 @@ static const char * const ad4170_int_pin_names[] = {
 	[AD4170_INT_PIN_DIG_AUX1] = "dig_aux1",
 };
 
+static const unsigned int ad4170_sinc3_filt_fs_tbl[] = {
+	4, 8, 12, 16, 20, 40, 48, 80,			/*  0 -  7 */
+	100, 256, 500, 1000, 5000, 8332, 10000, 25000,	/*  8 - 15 */
+	50000, 65532,					/* 16 - 17 */
+};
+
+#define AD4170_MAX_FS_TBL_SIZE		ARRAY_SIZE(ad4170_sinc3_filt_fs_tbl)
+
+static const unsigned int ad4170_sinc5_filt_fs_tbl[] = {
+	1, 2, 4, 8, 12, 16, 20, 40, 48, 80, 100, 256,
+};
+
 struct ad4170_chip_info {
 	const char *name;
 };

@@ -268,6 +302,12 @@ struct ad4170_chan_info {
 	bool enabled;
 };
 
+static const char * const ad4170_filt_names[] = {
+	[AD4170_SINC5_AVG] = "sinc5+avg",
+	[AD4170_SINC5] = "sinc5",
+	[AD4170_SINC3] = "sinc3",
+};
+
 struct ad4170_state {
 	struct mutex lock; /* Protect read-modify-write and multi write sequences */
 	int vrefs_uv[AD4170_MAX_SUP];

@@ -277,6 +317,7 @@ struct ad4170_state {
 	struct ad4170_chan_info chan_infos[AD4170_MAX_CHANNELS];
 	struct spi_device *spi;
 	struct regmap *regmap;
+	int sps_tbl[ARRAY_SIZE(ad4170_filt_names)][AD4170_MAX_FS_TBL_SIZE][2];
 	struct completion completion;
 	unsigned int pins_fn[AD4170_NUM_ANALOG_PINS];
 	u32 int_pin_sel;

@@ -288,6 +329,38 @@ struct ad4170_state {
 	u8 rx_buf[4];
 };
 
+static void ad4170_fill_sps_tbl(struct ad4170_state *st)
+{
+	unsigned int tmp0, tmp1, i;
+
+	/*
+	 * The ODR can be calculated the same way for sinc5+avg, sinc5, and
+	 * sinc3 filter types with the exception that sinc5 filter has a
+	 * narrowed range of allowed FILTER_FS values.
+	 */
+	for (i = 0; i < ARRAY_SIZE(ad4170_sinc3_filt_fs_tbl); i++) {
+		tmp0 = div_u64_rem(st->mclk_hz, 32 * ad4170_sinc3_filt_fs_tbl[i],
+				   &tmp1);
+		tmp1 = mult_frac(tmp1, MICRO, 32 * ad4170_sinc3_filt_fs_tbl[i]);
+		/* Fill sinc5+avg filter SPS table */
+		st->sps_tbl[AD4170_SINC5_AVG][i][0] = tmp0; /* Integer part */
+		st->sps_tbl[AD4170_SINC5_AVG][i][1] = tmp1; /* Fractional part */
+
+		/* Fill sinc3 filter SPS table */
+		st->sps_tbl[AD4170_SINC3][i][0] = tmp0; /* Integer part */
+		st->sps_tbl[AD4170_SINC3][i][1] = tmp1; /* Fractional part */
+	}
+	/* Sinc5 filter ODR doesn't use all FILTER_FS bits */
+	for (i = 0; i < ARRAY_SIZE(ad4170_sinc5_filt_fs_tbl); i++) {
+		tmp0 = div_u64_rem(st->mclk_hz, 32 * ad4170_sinc5_filt_fs_tbl[i],
+				   &tmp1);
+		tmp1 = mult_frac(tmp1, MICRO, 32 * ad4170_sinc5_filt_fs_tbl[i]);
+		/* Fill sinc5 filter SPS table */
+		st->sps_tbl[AD4170_SINC5][i][0] = tmp0; /* Integer part */
+		st->sps_tbl[AD4170_SINC5][i][1] = tmp1; /* Fractional part */
+	}
+}
+
 static int ad4170_debugfs_reg_access(struct iio_dev *indio_dev,
 				     unsigned int reg, unsigned int writeval,
 				     unsigned int *readval)

@@ -622,6 +695,100 @@ static int ad4170_set_channel_enable(struct ad4170_state *st,
 	return 0;
 }
 
+static int __ad4170_get_filter_type(unsigned int filter)
+{
+	u16 f_conf = FIELD_GET(AD4170_FILTER_FILTER_TYPE_MSK, filter);
+
+	switch (f_conf) {
+	case AD4170_FILTER_FILTER_TYPE_SINC5_AVG:
+		return AD4170_SINC5_AVG;
+	case AD4170_FILTER_FILTER_TYPE_SINC5:
+		return AD4170_SINC5;
+	case AD4170_FILTER_FILTER_TYPE_SINC3:
+		return AD4170_SINC3;
+	default:
+		return -EINVAL;
+	}
+}
+
+static int ad4170_set_filter_type(struct iio_dev *indio_dev,
+				  struct iio_chan_spec const *chan,
+				  unsigned int val)
+{
+	struct ad4170_state *st = iio_priv(indio_dev);
+	struct ad4170_chan_info *chan_info = &st->chan_infos[chan->address];
+	struct ad4170_setup *setup = &chan_info->setup;
+	unsigned int filter_type_conf;
+	int ret;
+
+	switch (val) {
+	case AD4170_SINC5_AVG:
+		filter_type_conf = AD4170_FILTER_FILTER_TYPE_SINC5_AVG;
+		break;
+	case AD4170_SINC5:
+		filter_type_conf = AD4170_FILTER_FILTER_TYPE_SINC5;
+		break;
+	case AD4170_SINC3:
+		filter_type_conf = AD4170_FILTER_FILTER_TYPE_SINC3;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	/*
+	 * The filters provide the same ODR for a given filter_fs value but
+	 * there are different minimum and maximum filter_fs limits for each
+	 * filter. The filter_fs value will be adjusted if the current filter_fs
+	 * is out of the limits of the just requested filter. Since the
+	 * filter_fs value affects the ODR (sampling_frequency), changing the
+	 * filter may lead to a change in the sampling frequency.
+	 */
+	scoped_guard(mutex, &st->lock) {
+		if (!iio_device_claim_direct(indio_dev))
+			return -EBUSY;
+
+		if (val == AD4170_SINC5_AVG || val == AD4170_SINC3)
+			setup->filter_fs = clamp(val, AD4170_SINC3_MIN_FS,
+						 AD4170_SINC3_MAX_FS);
+		else
+			setup->filter_fs = clamp(val, AD4170_SINC5_MIN_FS,
+						 AD4170_SINC5_MAX_FS);
+
+		setup->filter &= ~AD4170_FILTER_FILTER_TYPE_MSK;
+		setup->filter |= FIELD_PREP(AD4170_FILTER_FILTER_TYPE_MSK,
+					    filter_type_conf);
+
+		ret = ad4170_write_channel_setup(st, chan->address, false);
+		iio_device_release_direct(indio_dev);
+	}
+
+	return ret;
+}
+
+static int ad4170_get_filter_type(struct iio_dev *indio_dev,
+				  struct iio_chan_spec const *chan)
+{
+	struct ad4170_state *st = iio_priv(indio_dev);
+	struct ad4170_chan_info *chan_info = &st->chan_infos[chan->address];
+	struct ad4170_setup *setup = &chan_info->setup;
+
+	return __ad4170_get_filter_type(setup->filter);
+}
+
+static const struct iio_enum ad4170_filter_type_enum = {
+	.items = ad4170_filt_names,
+	.num_items = ARRAY_SIZE(ad4170_filt_names),
+	.get = ad4170_get_filter_type,
+	.set = ad4170_set_filter_type,
+};
+
+static const struct iio_chan_spec_ext_info ad4170_filter_type_ext_info[] = {
+	IIO_ENUM("filter_type", IIO_SEPARATE, &ad4170_filter_type_enum),
+	IIO_ENUM_AVAILABLE("filter_type", IIO_SHARED_BY_TYPE,
+			   &ad4170_filter_type_enum),
+	{ }
+};
+
 static const struct iio_chan_spec ad4170_channel_template = {
 	.type = IIO_VOLTAGE,
 	.indexed = 1,

@@ -630,8 +797,11 @@ static const struct iio_chan_spec ad4170_channel_template = {
 			      BIT(IIO_CHAN_INFO_SCALE) |
 			      BIT(IIO_CHAN_INFO_CALIBBIAS) |
 			      BIT(IIO_CHAN_INFO_CALIBSCALE) |
-			      BIT(IIO_CHAN_INFO_OFFSET),
-	.info_mask_separate_available = BIT(IIO_CHAN_INFO_SCALE),
+			      BIT(IIO_CHAN_INFO_OFFSET) |
+			      BIT(IIO_CHAN_INFO_SAMP_FREQ),
+	.info_mask_separate_available = BIT(IIO_CHAN_INFO_SCALE) |
+					BIT(IIO_CHAN_INFO_SAMP_FREQ),
+	.ext_info = ad4170_filter_type_ext_info,
 	.scan_type = {
 		.realbits = 24,
 		.storagebits = 32,

@@ -926,7 +1096,8 @@ static int ad4170_read_raw(struct iio_dev *indio_dev,
 	struct ad4170_state *st = iio_priv(indio_dev);
 	struct ad4170_chan_info *chan_info = &st->chan_infos[chan->address];
 	struct ad4170_setup *setup = &chan_info->setup;
-	unsigned int pga;
+	enum ad4170_filter_type f_type;
+	unsigned int pga, fs_idx;
 	int ret;
 
 	guard(mutex)(&st->lock);

@@ -947,6 +1118,27 @@ static int ad4170_read_raw(struct iio_dev *indio_dev,
 		pga = FIELD_GET(AD4170_AFE_PGA_GAIN_MSK, setup->afe);
 		*val = chan_info->offset_tbl[pga];
 		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		f_type = __ad4170_get_filter_type(setup->filter);
+		switch (f_type) {
+		case AD4170_SINC5_AVG:
+		case AD4170_SINC3:
+			fs_idx = find_closest(setup->filter_fs,
+					      ad4170_sinc3_filt_fs_tbl,
+					      ARRAY_SIZE(ad4170_sinc3_filt_fs_tbl));
+			*val = st->sps_tbl[f_type][fs_idx][0];
+			*val2 = st->sps_tbl[f_type][fs_idx][1];
+			return IIO_VAL_INT_PLUS_MICRO;
+		case AD4170_SINC5:
+			fs_idx = find_closest(setup->filter_fs,
+					      ad4170_sinc5_filt_fs_tbl,
+					      ARRAY_SIZE(ad4170_sinc5_filt_fs_tbl));
+			*val = st->sps_tbl[f_type][fs_idx][0];
+			*val2 = st->sps_tbl[f_type][fs_idx][1];
+			return IIO_VAL_INT_PLUS_MICRO;
+		default:
+			return -EINVAL;
+		}
 	case IIO_CHAN_INFO_CALIBBIAS:
 		*val = setup->offset;
 		return IIO_VAL_INT;

@@ -1032,6 +1224,7 @@ static int ad4170_read_avail(struct iio_dev *indio_dev,
 {
 	struct ad4170_state *st = iio_priv(indio_dev);
 	struct ad4170_chan_info *chan_info = &st->chan_infos[chan->address];
+	enum ad4170_filter_type f_type;
 
 	switch (info) {
 	case IIO_CHAN_INFO_SCALE:

@@ -1039,6 +1232,21 @@ static int ad4170_read_avail(struct iio_dev *indio_dev,
 		*length = ARRAY_SIZE(chan_info->scale_tbl) * 2;
 		*type = IIO_VAL_INT_PLUS_NANO;
 		return IIO_AVAIL_LIST;
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		f_type = ad4170_get_filter_type(indio_dev, chan);
+		*vals = (int *)st->sps_tbl[f_type];
+		*type = IIO_VAL_INT_PLUS_MICRO;
+		switch (f_type) {
+		case AD4170_SINC5_AVG:
+		case AD4170_SINC3:
+			*length = ARRAY_SIZE(ad4170_sinc3_filt_fs_tbl) * 2;
+			return IIO_AVAIL_LIST;
+		case AD4170_SINC5:
+			*length = ARRAY_SIZE(ad4170_sinc5_filt_fs_tbl) * 2;
+			return IIO_AVAIL_LIST;
+		default:
+			return -EINVAL;
+		}
 	default:
 		return -EINVAL;
 	}

@@ -1067,6 +1275,42 @@ static int ad4170_set_pga(struct ad4170_state *st,
 	return ad4170_write_channel_setup(st, chan->address, false);
 }
 
+static int ad4170_set_channel_freq(struct ad4170_state *st,
+				   struct iio_chan_spec const *chan, int val,
+				   int val2)
+{
+	struct ad4170_chan_info *chan_info = &st->chan_infos[chan->address];
+	struct ad4170_setup *setup = &chan_info->setup;
+	enum ad4170_filter_type f_type = __ad4170_get_filter_type(setup->filter);
+	unsigned int filt_fs_tbl_size, i;
+
+	switch (f_type) {
+	case AD4170_SINC5_AVG:
+	case AD4170_SINC3:
+		filt_fs_tbl_size = ARRAY_SIZE(ad4170_sinc3_filt_fs_tbl);
+		break;
+	case AD4170_SINC5:
+		filt_fs_tbl_size = ARRAY_SIZE(ad4170_sinc5_filt_fs_tbl);
+		break;
+	}
+
+	for (i = 0; i < filt_fs_tbl_size; i++) {
+		if (st->sps_tbl[f_type][i][0] == val &&
+		    st->sps_tbl[f_type][i][1] == val2)
+			break;
+	}
+	if (i == filt_fs_tbl_size)
+		return -EINVAL;
+
+	guard(mutex)(&st->lock);
+	if (f_type == AD4170_SINC5)
+		setup->filter_fs = ad4170_sinc5_filt_fs_tbl[i];
+	else
+		setup->filter_fs = ad4170_sinc3_filt_fs_tbl[i];
+
+	return ad4170_write_channel_setup(st, chan->address, false);
+}
+
 static int ad4170_set_calib_offset(struct ad4170_state *st,
 				   struct iio_chan_spec const *chan, int val)
 {

@@ -1100,6 +1344,8 @@ static int __ad4170_write_raw(struct iio_dev *indio_dev,
 	switch (info) {
 	case IIO_CHAN_INFO_SCALE:
 		return ad4170_set_pga(st, chan, val, val2);
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		return ad4170_set_channel_freq(st, chan, val, val2);
 	case IIO_CHAN_INFO_CALIBBIAS:
 		return ad4170_set_calib_offset(st, chan, val);
 	case IIO_CHAN_INFO_CALIBSCALE:

@@ -1130,6 +1376,8 @@ static int ad4170_write_raw_get_fmt(struct iio_dev *indio_dev,
 	switch (info) {
 	case IIO_CHAN_INFO_SCALE:
 		return IIO_VAL_INT_PLUS_NANO;
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		return IIO_VAL_INT_PLUS_MICRO;
 	case IIO_CHAN_INFO_CALIBBIAS:
 	case IIO_CHAN_INFO_CALIBSCALE:
 		return IIO_VAL_INT;

@@ -1366,6 +1614,8 @@ static int ad4170_initial_config(struct iio_dev *indio_dev)
 	unsigned int i;
 	int ret;
 
+	ad4170_fill_sps_tbl(st);
+
 	ret = regmap_update_bits(st->regmap, AD4170_ADC_CTRL_REG,
 				 AD4170_ADC_CTRL_MODE_MSK,
 				 FIELD_PREP(AD4170_ADC_CTRL_MODE_MSK,

@@ -1398,6 +1648,12 @@ static int ad4170_initial_config(struct iio_dev *indio_dev)
 			return dev_err_probe(dev, ret,
 					     "Failed to write CHAN_MAP_REG\n");
 
+		ret = ad4170_set_channel_freq(st, chan,
+					      AD4170_DEFAULT_SAMP_RATE, 0);
+		if (ret)
+			return dev_err_probe(dev, ret,
+					     "Failed to set channel freq\n");
+
 		ret = ad4170_fill_scale_tbl(indio_dev, chan);
 		if (ret)
 			return dev_err_probe(dev, ret,

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index 11d04c50e613..3ee66ac651f1 100644
@@ -875,6 +875,27 @@ static const struct iio_chan_spec ad4170_channel_template = {
 	},
 };
 
+static const struct iio_chan_spec ad4170_temp_channel_template = {
+	.type = IIO_TEMP,
+	.indexed = 0,
+	.channel = 17,
+	.channel2 = 17,
+	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+			      BIT(IIO_CHAN_INFO_SCALE) |
+			      BIT(IIO_CHAN_INFO_OFFSET) |
+			      BIT(IIO_CHAN_INFO_CALIBSCALE) |
+			      BIT(IIO_CHAN_INFO_CALIBBIAS) |
+			      BIT(IIO_CHAN_INFO_SAMP_FREQ),
+	.info_mask_separate_available = BIT(IIO_CHAN_INFO_SAMP_FREQ),
+	.scan_type = {
+		.sign = 's',
+		.realbits = 24,
+		.storagebits = 32,
+		.shift = 8,
+		.endianness = IIO_BE,
+	},
+};
+
 /*
  * Receives the number of a multiplexed AD4170 input (ain_n), and stores the
  * voltage (in µV) of the specified input into ain_voltage. If the input number

@@ -1177,9 +1198,27 @@ static int ad4170_read_raw(struct iio_dev *indio_dev,
 		return ret;
 	case IIO_CHAN_INFO_SCALE:
 		pga = FIELD_GET(AD4170_AFE_PGA_GAIN_MSK, setup->afe);
-		*val = chan_info->scale_tbl[pga][0];
-		*val2 = chan_info->scale_tbl[pga][1];
-		return IIO_VAL_INT_PLUS_NANO;
+		switch (chan->type) {
+		case IIO_VOLTAGE:
+			*val = chan_info->scale_tbl[pga][0];
+			*val2 = chan_info->scale_tbl[pga][1];
+			return IIO_VAL_INT_PLUS_NANO;
+
+		case IIO_TEMP:
+			/*
+			 * The scale_tbl converts output codes to mV units so
+			 * multiply by MILLI to make the factor convert to µV.
+			 * Then, apply the temperature sensor change sensitivity
+			 * of 477 μV/K. Finally, multiply the result by MILLI
+			 * again to comply with milli degrees Celsius IIO ABI.
+			 */
+			*val = 0;
+			*val2 = DIV_ROUND_CLOSEST(chan_info->scale_tbl[pga][1] * MILLI, 477) *
+						  MILLI;
+			return IIO_VAL_INT_PLUS_NANO;
+		default:
+			return -EINVAL;
+		}
 	case IIO_CHAN_INFO_OFFSET:
 		pga = FIELD_GET(AD4170_AFE_PGA_GAIN_MSK, setup->afe);
 		*val = chan_info->offset_tbl[pga];

@@ -1835,6 +1874,9 @@ static int ad4170_parse_channels(struct iio_dev *indio_dev)
 	if (num_channels > AD4170_MAX_CHANNELS)
 		return dev_err_probe(dev, -EINVAL, "Too many channels\n");
 
+	/* Add one for temperature */
+	num_channels = min(num_channels + 1, AD4170_MAX_CHANNELS);
+
 	chan_num = 0;
 	device_for_each_child_node_scoped(dev, child) {
 		ret = ad4170_parse_channel_node(indio_dev, child, chan_num++);

@@ -1842,6 +1884,30 @@ static int ad4170_parse_channels(struct iio_dev *indio_dev)
 			return ret;
 	}
 
+	/*
+	 * Add internal temperature sensor channel if the maximum number of
+	 * channels has not been reached.
+	 */
+	if (num_channels < AD4170_MAX_CHANNELS) {
+		struct ad4170_setup *setup = &st->chan_infos[chan_num].setup;
+
+		st->chans[chan_num] = ad4170_temp_channel_template;
+		st->chans[chan_num].address = chan_num;
+		st->chans[chan_num].scan_index = chan_num;
+
+		st->chan_infos[chan_num].setup_num = AD4170_INVALID_SETUP;
+		st->chan_infos[chan_num].initialized = true;
+
+		setup->afe |= FIELD_PREP(AD4170_AFE_REF_SELECT_MSK,
+					 AD4170_REF_AVDD);
+
+		ret = ad4170_get_input_range(st, &st->chans[chan_num], chan_num,
+					     AD4170_REF_AVDD);
+		if (ret < 0)
+			return dev_err_probe(dev, ret, "Invalid input config\n");
+
+		st->chan_infos[chan_num].input_range_uv = ret;
+	}
 	indio_dev->num_channels = num_channels;
 	indio_dev->channels = st->chans;
 

index 3ee66ac651f1..2a2d4a05e9af 100644
@@ -67,6 +67,8 @@
 #define AD4170_FILTER_FS_REG(x)				(0xC7 + 14 * (x))
 #define AD4170_OFFSET_REG(x)				(0xCA + 14 * (x))
 #define AD4170_GAIN_REG(x)				(0xCD + 14 * (x))
+#define AD4170_V_BIAS_REG				0x135
+#define AD4170_CURRENT_SRC_REG(x)			(0x139 + 2 * (x))
 #define AD4170_GPIO_MODE_REG				0x191
 #define AD4170_GPIO_OUTPUT_REG				0x193
 #define AD4170_GPIO_INPUT_REG				0x195

@@ -98,6 +100,10 @@
 #define AD4170_CHAN_MAP_AINP_MSK			GENMASK(12, 8)
 #define AD4170_CHAN_MAP_AINM_MSK			GENMASK(4, 0)
 
+/* AD4170_MISC_REG */
+#define AD4170_MISC_CHOP_IEXC_MSK			GENMASK(15, 14)
+#define AD4170_MISC_CHOP_ADC_MSK			GENMASK(9, 8)
+
 /* AD4170_AFE_REG */
 #define AD4170_AFE_REF_BUF_M_MSK			GENMASK(11, 10)
 #define AD4170_AFE_REF_BUF_P_MSK			GENMASK(9, 8)

@@ -108,12 +114,19 @@
 /* AD4170_FILTER_REG */
 #define AD4170_FILTER_FILTER_TYPE_MSK			GENMASK(3, 0)
 
+/* AD4170_CURRENT_SRC_REG */
+#define AD4170_CURRENT_SRC_I_OUT_PIN_MSK		GENMASK(12, 8)
+#define AD4170_CURRENT_SRC_I_OUT_VAL_MSK		GENMASK(2, 0)
+
 /* AD4170_GPIO_MODE_REG */
 #define AD4170_GPIO_MODE_GPIO0_MSK			GENMASK(1, 0)
 #define AD4170_GPIO_MODE_GPIO1_MSK			GENMASK(3, 2)
 #define AD4170_GPIO_MODE_GPIO2_MSK			GENMASK(5, 4)
 #define AD4170_GPIO_MODE_GPIO3_MSK			GENMASK(7, 6)
 
+/* AD4170_GPIO_OUTPUT_REG */
+#define AD4170_GPIO_OUTPUT_GPIO_MSK(x)			BIT(x)
+
 /* AD4170 register constants */
 
 /* AD4170_CLOCK_CTRL_REG constants */

@@ -137,6 +150,11 @@
 #define AD4170_CHAN_MAP_REFIN2_N		28
 #define AD4170_CHAN_MAP_REFOUT			29
 
+/* AD4170_MISC_REG constants */
+#define AD4170_MISC_CHOP_IEXC_PAIR1			0x1
+#define AD4170_MISC_CHOP_IEXC_PAIR2			0x2
+#define AD4170_MISC_CHOP_IEXC_BOTH			0x3
+
 /* AD4170_PIN_MUXING_REG constants */
 #define AD4170_PIN_MUXING_DIG_AUX1_DISABLED		0x0
 #define AD4170_PIN_MUXING_DIG_AUX1_RDY			0x1

@@ -154,6 +172,10 @@
 #define AD4170_FILTER_FILTER_TYPE_SINC5			0x4
 #define AD4170_FILTER_FILTER_TYPE_SINC3			0x6
 
+/* AD4170_CURRENT_SRC_REG constants */
+#define AD4170_CURRENT_SRC_I_OUT_PIN_AIN(x)		(x)
+#define AD4170_CURRENT_SRC_I_OUT_PIN_GPIO(x)		((x) + 17)
+
 /* AD4170_GPIO_MODE_REG constants */
 #define AD4170_GPIO_MODE_GPIO_INPUT			1
 #define AD4170_GPIO_MODE_GPIO_OUTPUT			2

@@ -168,6 +190,7 @@
 #define AD4170_INVALID_SETUP				9
 #define AD4170_SPI_INST_PHASE_LEN			2
 #define AD4170_SPI_MAX_XFER_LEN				6
+#define AD4170_NUM_CURRENT_SRC				4
 #define AD4170_DEFAULT_SAMP_RATE			(125 * HZ_PER_KHZ)
 
 #define AD4170_INT_REF_2_5V				2500000

@@ -189,8 +212,19 @@
 
 #define AD4170_ADC_CTRL_CONT_READ_EXIT			0xA5
 
+/* Analog pin functions  */
+#define AD4170_PIN_UNASSIGNED				0x00
+#define AD4170_PIN_ANALOG_IN				0x01
+#define AD4170_PIN_CURRENT_OUT				0x02
+#define AD4170_PIN_VBIAS				0x04
+
 /* GPIO pin functions  */
 #define AD4170_GPIO_UNASSIGNED				0x00
+#define AD4170_GPIO_AC_EXCITATION			0x02
+#define AD4170_GPIO_OUTPUT				0x04
+
+/* Current source */
+#define AD4170_CURRENT_SRC_DISABLED			0xFF
 
 static const unsigned int ad4170_reg_size[] = {
 	[AD4170_CONFIG_A_REG] = 1,

@@ -229,6 +263,8 @@ static const unsigned int ad4170_reg_size[] = {
 	[AD4170_OFFSET_REG(5) ... AD4170_GAIN_REG(5)] = 3,
 	[AD4170_OFFSET_REG(6) ... AD4170_GAIN_REG(6)] = 3,
 	[AD4170_OFFSET_REG(7) ... AD4170_GAIN_REG(7)] = 3,
+	[AD4170_V_BIAS_REG] = 2,
+	[AD4170_CURRENT_SRC_REG(0) ... AD4170_CURRENT_SRC_REG(3)] = 2,
 	[AD4170_GPIO_MODE_REG] = 2,
 	[AD4170_GPIO_OUTPUT_REG] = 2,
 	[AD4170_GPIO_INPUT_REG] = 2,

@@ -298,6 +334,41 @@ static const unsigned int ad4170_sinc5_filt_fs_tbl[] = {
 	1, 2, 4, 8, 12, 16, 20, 40, 48, 80, 100, 256,
 };
 
+static const unsigned int ad4170_iout_pin_tbl[] = {
+	AD4170_CURRENT_SRC_I_OUT_PIN_AIN(0),
+	AD4170_CURRENT_SRC_I_OUT_PIN_AIN(1),
+	AD4170_CURRENT_SRC_I_OUT_PIN_AIN(2),
+	AD4170_CURRENT_SRC_I_OUT_PIN_AIN(3),
+	AD4170_CURRENT_SRC_I_OUT_PIN_AIN(4),
+	AD4170_CURRENT_SRC_I_OUT_PIN_AIN(5),
+	AD4170_CURRENT_SRC_I_OUT_PIN_AIN(6),
+	AD4170_CURRENT_SRC_I_OUT_PIN_AIN(7),
+	AD4170_CURRENT_SRC_I_OUT_PIN_AIN(8),
+	AD4170_CURRENT_SRC_I_OUT_PIN_GPIO(0),
+	AD4170_CURRENT_SRC_I_OUT_PIN_GPIO(1),
+	AD4170_CURRENT_SRC_I_OUT_PIN_GPIO(2),
+	AD4170_CURRENT_SRC_I_OUT_PIN_GPIO(3),
+};
+
+static const unsigned int ad4170_iout_current_ua_tbl[] = {
+	0, 10, 50, 100, 250, 500, 1000, 1500,
+};
+
+enum ad4170_sensor_enum {
+	AD4170_ADC_SENSOR = 0,
+	AD4170_WEIGH_SCALE_SENSOR = 1,
+	AD4170_RTD_SENSOR = 2,
+	AD4170_THERMOCOUPLE_SENSOR = 3,
+};
+
+/* maps adi,sensor-type property value to enum */
+static const char * const ad4170_sensor_type[] = {
+	[AD4170_ADC_SENSOR] = "adc",
+	[AD4170_WEIGH_SCALE_SENSOR] = "weighscale",
+	[AD4170_RTD_SENSOR] = "rtd",
+	[AD4170_THERMOCOUPLE_SENSOR] = "thermocouple",
+};
+
 struct ad4170_chip_info {
 	const char *name;
 };

@@ -382,6 +453,7 @@ struct ad4170_state {
 	struct gpio_chip gpiochip;
 	unsigned int clock_ctrl;
 	int gpio_fn[AD4170_NUM_GPIO_PINS];
+	unsigned int cur_src_pins[AD4170_NUM_CURRENT_SRC];
 	/*
 	 * DMA (thus cache coherency maintenance) requires the transfer buffers
 	 * to live in their own cache lines.

@@ -910,6 +982,19 @@ static int ad4170_get_ain_voltage_uv(struct ad4170_state *st, int ain_n,
 	int v_diff;
 
 	*ain_voltage = 0;
+	/*
+	 * The voltage bias (vbias) sets the common-mode voltage of the channel
+	 * to (AVDD + AVSS)/2. If provided, AVSS supply provides the magnitude
+	 * (absolute value) of the negative voltage supplied to the AVSS pin.
+	 * So, we do AVDD - AVSS to compute the DC voltage generated by the bias
+	 * voltage generator.
+	 */
+	if (st->pins_fn[ain_n] & AD4170_PIN_VBIAS) {
+		int v_diff = st->vrefs_uv[AD4170_AVDD_SUP] - st->vrefs_uv[AD4170_AVSS_SUP];
+		*ain_voltage = v_diff / 2;
+		return 0;
+	}
+
 	if (ain_n <= AD4170_CHAN_MAP_TEMP_SENSOR)
 		return 0;
 

@@ -964,6 +1049,19 @@ static int ad4170_get_ain_voltage_uv(struct ad4170_state *st, int ain_n,
 	}
 }
 
+static int ad4170_validate_analog_input(struct ad4170_state *st, int pin)
+{
+	if (pin <= AD4170_MAX_ANALOG_PINS) {
+		if (st->pins_fn[pin] & AD4170_PIN_CURRENT_OUT)
+			return dev_err_probe(&st->spi->dev, -EINVAL,
+					     "Pin %d already used with fn %u.\n",
+					     pin, st->pins_fn[pin]);
+
+		st->pins_fn[pin] |= AD4170_PIN_ANALOG_IN;
+	}
+	return 0;
+}
+
 static int ad4170_validate_channel_input(struct ad4170_state *st, int pin, bool com)
 {
 	/* Check common-mode input pin is mapped to a special input. */

@@ -978,7 +1076,7 @@ static int ad4170_validate_channel_input(struct ad4170_state *st, int pin, bool
 				     "Invalid analog input pin number. %d\n",
 				     pin);
 
-	return 0;
+	return ad4170_validate_analog_input(st, pin);
 }
 
 /*

@@ -1718,6 +1816,371 @@ static int ad4170_gpio_init(struct iio_dev *indio_dev)
 	return devm_gpiochip_add_data(&st->spi->dev, &st->gpiochip, indio_dev);
 }
 
+static int ad4170_validate_excitation_pin(struct ad4170_state *st, u32 pin)
+{
+	struct device *dev = &st->spi->dev;
+	unsigned int i;
+
+	/* Check the pin number is valid */
+	for (i = 0; i < ARRAY_SIZE(ad4170_iout_pin_tbl); i++)
+		if (ad4170_iout_pin_tbl[i] == pin)
+			break;
+
+	if (i == ARRAY_SIZE(ad4170_iout_pin_tbl))
+		return dev_err_probe(dev, -EINVAL,
+				     "Invalid excitation pin: %u\n",
+				     pin);
+
+	/* Check the pin is available */
+	if (pin <= AD4170_MAX_ANALOG_PINS) {
+		if (st->pins_fn[pin] != AD4170_PIN_UNASSIGNED)
+			return dev_err_probe(dev, -EINVAL,
+					     "Pin %u already used with fn %u\n",
+					     pin, st->pins_fn[pin]);
+
+		st->pins_fn[pin] |= AD4170_PIN_CURRENT_OUT;
+	} else {
+		unsigned int gpio = pin - AD4170_CURRENT_SRC_I_OUT_PIN_GPIO(0);
+
+		if (st->gpio_fn[gpio] != AD4170_GPIO_UNASSIGNED)
+			return dev_err_probe(dev, -EINVAL,
+					     "GPIO %u already used with fn %u\n",
+					     gpio, st->gpio_fn[gpio]);
+
+		st->gpio_fn[gpio] |= AD4170_GPIO_AC_EXCITATION;
+	}
+
+	return 0;
+}
+
+static int ad4170_validate_excitation_pins(struct ad4170_state *st,
+					   u32 *exc_pins, int num_exc_pins)
+{
+	unsigned int i;
+	int ret;
+
+	for (i = 0; i < num_exc_pins; i++) {
+		ret = ad4170_validate_excitation_pin(st, exc_pins[i]);
+		if (ret)
+			return ret;
+	}
+	return 0;
+}
+
+static const char *const ad4170_i_out_pin_dt_props[] = {
+	"adi,excitation-pin-0",
+	"adi,excitation-pin-1",
+	"adi,excitation-pin-2",
+	"adi,excitation-pin-3",
+};
+
+static const char *const ad4170_i_out_val_dt_props[] = {
+	"adi,excitation-current-0-microamp",
+	"adi,excitation-current-1-microamp",
+	"adi,excitation-current-2-microamp",
+	"adi,excitation-current-3-microamp",
+};
+
+/*
+ * Parses firmware data describing output current source setup. There are 4
+ * excitation currents (IOUT0 to IOUT3) that can be configured independently.
+ * Excitation currents are added if they are output on the same pin.
+ */
+static int ad4170_parse_exc_current(struct ad4170_state *st,
+				    struct fwnode_handle *child,
+				    unsigned int *exc_pins,
+				    unsigned int *exc_curs,
+				    unsigned int *num_exc_pins)
+{
+	struct device *dev = &st->spi->dev;
+	unsigned int num_pins, i, j;
+	u32 pin, val;
+	int ret;
+
+	num_pins = 0;
+	for (i = 0; i < AD4170_NUM_CURRENT_SRC; i++) {
+		/* Parse excitation current output pin properties. */
+		pin = AD4170_CURRENT_SRC_I_OUT_PIN_AIN(0);
+		ret = fwnode_property_read_u32(child, ad4170_i_out_pin_dt_props[i],
+					       &pin);
+		if (ret)
+			continue;
+
+		exc_pins[num_pins] = pin;
+
+		/* Parse excitation current value properties. */
+		val = ad4170_iout_current_ua_tbl[0];
+		fwnode_property_read_u32(child,
+					 ad4170_i_out_val_dt_props[i], &val);
+
+		for (j = 0; j < ARRAY_SIZE(ad4170_iout_current_ua_tbl); j++)
+			if (ad4170_iout_current_ua_tbl[j] == val)
+				break;
+
+		if (j == ARRAY_SIZE(ad4170_iout_current_ua_tbl))
+			return dev_err_probe(dev, -EINVAL, "Invalid %s: %uuA\n",
+					     ad4170_i_out_val_dt_props[i], val);
+
+		exc_curs[num_pins] = j;
+		num_pins++;
+	}
+	*num_exc_pins = num_pins;
+
+	return 0;
+}
+
+static int ad4170_setup_current_src(struct ad4170_state *st,
+				    struct fwnode_handle *child,
+				    struct ad4170_setup *setup, u32 *exc_pins,
+				    unsigned int *exc_curs, int num_exc_pins,
+				    bool ac_excited)
+{
+	unsigned int exc_cur_pair, i, j;
+	int ret;
+
+	for (i = 0; i < num_exc_pins; i++) {
+		unsigned int exc_cur = exc_curs[i];
+		unsigned int pin = exc_pins[i];
+		unsigned int current_src = 0;
+
+		for (j = 0; j < AD4170_NUM_CURRENT_SRC; j++)
+			if (st->cur_src_pins[j] == AD4170_CURRENT_SRC_DISABLED)
+				break;
+
+		if (j == AD4170_NUM_CURRENT_SRC)
+			return dev_err_probe(&st->spi->dev, -EINVAL,
+					     "Too many excitation current sources\n");
+
+		current_src |= FIELD_PREP(AD4170_CURRENT_SRC_I_OUT_PIN_MSK, pin);
+		current_src |= FIELD_PREP(AD4170_CURRENT_SRC_I_OUT_VAL_MSK, exc_cur);
+		st->cur_src_pins[j] = pin;
+		ret = regmap_write(st->regmap, AD4170_CURRENT_SRC_REG(j),
+				   current_src);
+		if (ret)
+			return ret;
+	}
+
+	if (!ac_excited)
+		return 0;
+
+	if (num_exc_pins < 2)
+		return dev_err_probe(&st->spi->dev, -EINVAL,
+			"Current chopping requested but only one pin provided: %u\n",
+			exc_pins[0]);
+
+	/*
+	 * Two use cases to handle here:
+	 * - 2 pairs of excitation currents;
+	 * - 1 pair of excitation currents.
+	 */
+	if (num_exc_pins == 4) {
+		for (i = 0; i < AD4170_NUM_CURRENT_SRC; i++)
+			if (st->cur_src_pins[i] != exc_pins[i])
+				return dev_err_probe(&st->spi->dev, -EINVAL,
+						     "Unable to use 4 exc pins\n");
+	} else {
+		/*
+		 * Excitation current chopping is configured in pairs. Current
+		 * sources IOUT0 and IOUT1 form pair 1, IOUT2 and IOUT3 make up
+		 * pair 2. So, if current chopping was requested, check if the
+		 * first end of the first pair of excitation currents is
+		 * available. Try the next pair if IOUT0 has already been
+		 * configured for another channel.
+		 */
+		i = st->cur_src_pins[0] == exc_pins[0] ? 0 : 2;
+
+		if (st->cur_src_pins[i] != exc_pins[0] ||
+		    st->cur_src_pins[i + 1] != exc_pins[1])
+			return dev_err_probe(&st->spi->dev, -EINVAL,
+					     "Failed to setup current chopping\n");
+
+		st->cur_src_pins[i] = exc_pins[0];
+		st->cur_src_pins[i + 1] = exc_pins[1];
+
+		if (i == 0)
+			exc_cur_pair = AD4170_MISC_CHOP_IEXC_PAIR1;
+		else
+			exc_cur_pair = AD4170_MISC_CHOP_IEXC_PAIR2;
+	}
+
+	/*
+	 * Configure excitation current chopping.
+	 * Chop both pairs if using four excitation pins.
+	 */
+	setup->misc |= FIELD_PREP(AD4170_MISC_CHOP_IEXC_MSK,
+				  num_exc_pins == 2 ?
+				  exc_cur_pair :
+				  AD4170_MISC_CHOP_IEXC_BOTH);
+
+	return 0;
+}
+
+static int ad4170_setup_bridge(struct ad4170_state *st,
+			       struct fwnode_handle *child,
+			       struct ad4170_setup *setup, u32 *exc_pins,
+			       unsigned int *exc_curs, int num_exc_pins,
+			       bool ac_excited)
+{
+	unsigned long gpio_mask;
+	unsigned int i;
+	int ret;
+
+	/*
+	 * If a specific current is provided through
+	 * adi,excitation-current-n-microamp, set excitation pins provided
+	 * through adi,excitation-pin-n to excite the bridge circuit.
+	 */
+	for (i = 0; i < num_exc_pins; i++)
+		if (exc_curs[i] > 0)
+			return ad4170_setup_current_src(st, child, setup, exc_pins,
+							exc_curs, num_exc_pins,
+							ac_excited);
+
+	/*
+	 * Else, use predefined ACX1, ACX1 negated, ACX2, ACX2 negated signals
+	 * to AC excite the bridge. Those signals are output on GPIO2, GPIO0,
+	 * GPIO3, and GPIO1, respectively. If only two pins are specified for AC
+	 * excitation, use ACX1 and ACX2 (GPIO2 and GPIO3).
+	 *
+	 * Also, to avoid any short-circuit condition when more than one channel
+	 * is enabled, set GPIO2 and GPIO0 high, and set GPIO1 and GPIO3 low to
+	 * DC excite the bridge whenever a channel without AC excitation is
+	 * selected. That is needed because GPIO pins are controlled by the next
+	 * highest priority GPIO function when a channel doesn't enable AC
+	 * excitation. See datasheet Figure 113 Weigh Scale (AC Excitation) for
+	 * the reference circuit diagram.
+	 */
+	if (num_exc_pins == 2) {
+		setup->misc |= FIELD_PREP(AD4170_MISC_CHOP_ADC_MSK, 0x3);
+
+		gpio_mask = AD4170_GPIO_MODE_GPIO3_MSK | AD4170_GPIO_MODE_GPIO2_MSK;
+		ret = regmap_update_bits(st->regmap, AD4170_GPIO_MODE_REG, gpio_mask,
+					 FIELD_PREP(AD4170_GPIO_MODE_GPIO3_MSK,
+						    AD4170_GPIO_MODE_GPIO_OUTPUT) |
+					 FIELD_PREP(AD4170_GPIO_MODE_GPIO2_MSK,
+						    AD4170_GPIO_MODE_GPIO_OUTPUT));
+		if (ret)
+			return ret;
+
+		/*
+		 * Set GPIO2 high and GPIO3 low to DC excite the bridge when
+		 * a different channel is selected.
+		 */
+		gpio_mask = AD4170_GPIO_OUTPUT_GPIO_MSK(3) |
+			    AD4170_GPIO_OUTPUT_GPIO_MSK(2);
+		ret = regmap_update_bits(st->regmap, AD4170_GPIO_OUTPUT_REG, gpio_mask,
+					 FIELD_PREP(AD4170_GPIO_OUTPUT_GPIO_MSK(3), 0) |
+					 FIELD_PREP(AD4170_GPIO_OUTPUT_GPIO_MSK(2), 1));
+		if (ret)
+			return ret;
+
+		st->gpio_fn[3] |= AD4170_GPIO_OUTPUT;
+		st->gpio_fn[2] |= AD4170_GPIO_OUTPUT;
+	} else {
+		setup->misc |= FIELD_PREP(AD4170_MISC_CHOP_ADC_MSK, 0x2);
+
+		gpio_mask = AD4170_GPIO_MODE_GPIO3_MSK | AD4170_GPIO_MODE_GPIO2_MSK |
+			    AD4170_GPIO_MODE_GPIO1_MSK | AD4170_GPIO_MODE_GPIO0_MSK;
+		ret = regmap_update_bits(st->regmap, AD4170_GPIO_MODE_REG, gpio_mask,
+					 FIELD_PREP(AD4170_GPIO_MODE_GPIO3_MSK,
+						    AD4170_GPIO_MODE_GPIO_OUTPUT) |
+					 FIELD_PREP(AD4170_GPIO_MODE_GPIO2_MSK,
+						    AD4170_GPIO_MODE_GPIO_OUTPUT) |
+					 FIELD_PREP(AD4170_GPIO_MODE_GPIO1_MSK,
+						    AD4170_GPIO_MODE_GPIO_OUTPUT) |
+					 FIELD_PREP(AD4170_GPIO_MODE_GPIO0_MSK,
+						    AD4170_GPIO_MODE_GPIO_OUTPUT));
+		if (ret)
+			return ret;
+
+		/*
+		 * Set GPIO2 and GPIO0 high, and set GPIO1 and GPIO3 low to DC
+		 * excite the bridge when a different channel is selected.
+		 */
+		gpio_mask = AD4170_GPIO_OUTPUT_GPIO_MSK(3) |
+			    AD4170_GPIO_OUTPUT_GPIO_MSK(2) |
+			    AD4170_GPIO_OUTPUT_GPIO_MSK(1) |
+			    AD4170_GPIO_OUTPUT_GPIO_MSK(0);
+		ret = regmap_update_bits(st->regmap, AD4170_GPIO_OUTPUT_REG, gpio_mask,
+					 FIELD_PREP(AD4170_GPIO_OUTPUT_GPIO_MSK(3), 0) |
+					 FIELD_PREP(AD4170_GPIO_OUTPUT_GPIO_MSK(2), 1) |
+					 FIELD_PREP(AD4170_GPIO_OUTPUT_GPIO_MSK(1), 0) |
+					 FIELD_PREP(AD4170_GPIO_OUTPUT_GPIO_MSK(0), 1));
+		if (ret)
+			return ret;
+
+		st->gpio_fn[3] |= AD4170_GPIO_OUTPUT;
+		st->gpio_fn[2] |= AD4170_GPIO_OUTPUT;
+		st->gpio_fn[1] |= AD4170_GPIO_OUTPUT;
+		st->gpio_fn[0] |= AD4170_GPIO_OUTPUT;
+	}
+
+	return 0;
+}
+
+static int ad4170_setup_rtd(struct ad4170_state *st,
+			    struct fwnode_handle *child,
+			    struct ad4170_setup *setup, u32 *exc_pins,
+			    unsigned int *exc_curs, int num_exc_pins, bool ac_excited)
+{
+	return ad4170_setup_current_src(st, child, setup, exc_pins,
+					exc_curs, num_exc_pins, ac_excited);
+}
+
+static int ad4170_parse_external_sensor(struct ad4170_state *st,
+					struct fwnode_handle *child,
+					struct ad4170_setup *setup,
+					struct iio_chan_spec *chan, u8 s_type)
+{
+	unsigned int num_exc_pins, reg_val;
+	struct device *dev = &st->spi->dev;
+	u32 pins[2], exc_pins[4], exc_curs[4];
+	bool ac_excited, vbias;
+	int ret;
+
+	ret = fwnode_property_read_u32_array(child, "diff-channels", pins,
+					     ARRAY_SIZE(pins));
+	if (ret)
+		return dev_err_probe(dev, ret,
+				     "Failed to read sensor diff-channels\n");
+
+	chan->differential = true;
+	chan->channel = pins[0];
+	chan->channel2 = pins[1];
+
+	ret = ad4170_parse_exc_current(st, child, exc_pins, exc_curs, &num_exc_pins);
+	if (ret)
+		return ret;
+
+	/* The external sensor may not need excitation from the ADC chip. */
+	if (num_exc_pins == 0)
+		return 0;
+
+	ret = ad4170_validate_excitation_pins(st, exc_pins, num_exc_pins);
+	if (ret)
+		return ret;
+
+	ac_excited = fwnode_property_read_bool(child, "adi,excitation-ac");
+
+	if (s_type == AD4170_THERMOCOUPLE_SENSOR) {
+		vbias = fwnode_property_read_bool(child, "adi,vbias");
+		if (vbias) {
+			st->pins_fn[chan->channel2] |= AD4170_PIN_VBIAS;
+			reg_val = BIT(chan->channel2);
+			return regmap_write(st->regmap, AD4170_V_BIAS_REG,
+					    reg_val);
+		}
+	}
+	if (s_type == AD4170_WEIGH_SCALE_SENSOR)
+		ret = ad4170_setup_bridge(st, child, setup, exc_pins, exc_curs,
+					  num_exc_pins, ac_excited);
+	else
+		ret = ad4170_setup_rtd(st, child, setup, exc_pins, exc_curs,
+				       num_exc_pins, ac_excited);
+
+	return ret;
+}
+
 static int ad4170_parse_reference(struct ad4170_state *st,
 				  struct fwnode_handle *child,
 				  struct ad4170_setup *setup)

@@ -1810,6 +2273,7 @@ static int ad4170_parse_channel_node(struct iio_dev *indio_dev,
 	struct ad4170_setup *setup;
 	struct iio_chan_spec *chan;
 	unsigned int ref_select;
+	unsigned int s_type;
 	unsigned int ch_reg;
 	bool bipolar;
 	int ret;

@@ -1837,10 +2301,28 @@ static int ad4170_parse_channel_node(struct iio_dev *indio_dev,
 	if (ret)
 		return ret;
 
-	ret = ad4170_parse_adc_channel_type(dev, child, chan);
-	if (ret)
-		return ret;
+	ret = fwnode_property_match_property_string(child, "adi,sensor-type",
+						    ad4170_sensor_type,
+						    ARRAY_SIZE(ad4170_sensor_type));
 
+	/* Default to conventional ADC channel if sensor type not present */
+	s_type = ret < 0 ? AD4170_ADC_SENSOR : ret;
+	switch (s_type) {
+	case AD4170_ADC_SENSOR:
+		ret = ad4170_parse_adc_channel_type(dev, child, chan);
+		if (ret)
+			return ret;
+
+		break;
+	case AD4170_WEIGH_SCALE_SENSOR:
+	case AD4170_THERMOCOUPLE_SENSOR:
+	case AD4170_RTD_SENSOR:
+		ret = ad4170_parse_external_sensor(st, child, setup, chan, s_type);
+		if (ret)
+			return ret;
+
+		break;
+	}
 	bipolar = fwnode_property_read_bool(child, "bipolar");
 	setup->afe |= FIELD_PREP(AD4170_AFE_BIPOLAR_MSK, bipolar);
 	if (bipolar)

@@ -2037,6 +2519,7 @@ static int ad4170_parse_firmware(struct iio_dev *indio_dev)
 	struct ad4170_state *st = iio_priv(indio_dev);
 	struct device *dev = &st->spi->dev;
 	int reg_data, ret;
+	unsigned int i;
 
 	ret = ad4170_clock_select(indio_dev);
 	if (ret)

@@ -2046,6 +2529,9 @@ static int ad4170_parse_firmware(struct iio_dev *indio_dev)
 	if (ret)
 		return ret;
 
+	for (i = 0; i < AD4170_NUM_CURRENT_SRC; i++)
+		st->cur_src_pins[i] = AD4170_CURRENT_SRC_DISABLED;
+
 	/* On power on, device defaults to using SDO pin for data ready signal */
 	st->int_pin_sel = AD4170_INT_PIN_SDO;
 	ret = device_property_match_property_string(dev, "interrupt-names",

index 2a2d4a05e9af..33b9a6b2255b 100644
@@ -185,6 +185,7 @@
 #define AD4170_NUM_ANALOG_PINS				9
 #define AD4170_NUM_GPIO_PINS				4
 #define AD4170_MAX_CHANNELS				16
+#define AD4170_MAX_IIO_CHANNELS				(AD4170_MAX_CHANNELS + 1)
 #define AD4170_MAX_ANALOG_PINS				8
 #define AD4170_MAX_SETUPS				8
 #define AD4170_INVALID_SETUP				9

@@ -437,7 +438,7 @@ struct ad4170_state {
 	int vrefs_uv[AD4170_MAX_SUP];
 	u32 mclk_hz;
 	struct ad4170_setup_info setup_infos[AD4170_MAX_SETUPS];
-	struct iio_chan_spec chans[AD4170_MAX_CHANNELS];
+	struct iio_chan_spec chans[AD4170_MAX_IIO_CHANNELS];
 	struct ad4170_chan_info chan_infos[AD4170_MAX_CHANNELS];
 	struct spi_device *spi;
 	struct regmap *regmap;

@@ -454,6 +455,7 @@ struct ad4170_state {
 	unsigned int clock_ctrl;
 	int gpio_fn[AD4170_NUM_GPIO_PINS];
 	unsigned int cur_src_pins[AD4170_NUM_CURRENT_SRC];
+	unsigned int num_adc_chans;
 	/*
 	 * DMA (thus cache coherency maintenance) requires the transfer buffers
 	 * to live in their own cache lines.

@@ -2389,7 +2391,16 @@ static int ad4170_parse_channels(struct iio_dev *indio_dev)
 			return dev_err_probe(dev, ret, "Invalid input config\n");
 
 		st->chan_infos[chan_num].input_range_uv = ret;
+		chan_num++;
 	}
+	st->num_adc_chans = chan_num;
+
+	/* Add timestamp channel */
+	struct iio_chan_spec ts_chan = IIO_CHAN_SOFT_TIMESTAMP(chan_num);
+
+	st->chans[chan_num] = ts_chan;
+	num_channels = num_channels + 1;
+
 	indio_dev->num_channels = num_channels;
 	indio_dev->channels = st->chans;
 

@@ -2581,7 +2592,7 @@ static int ad4170_initial_config(struct iio_dev *indio_dev)
 		return dev_err_probe(dev, ret,
 				     "Failed to set ADC mode to idle\n");
 
-	for (i = 0; i < indio_dev->num_channels; i++) {
+	for (i = 0; i < st->num_adc_chans; i++) {
 		struct ad4170_chan_info *chan_info;
 		struct iio_chan_spec const *chan;
 		struct ad4170_setup *setup;

@@ -2706,7 +2717,7 @@ static int ad4170_buffer_predisable(struct iio_dev *indio_dev)
 	 * is done after buffer disable. Disable all channels so only requested
 	 * channels will be read.
 	 */
-	for (i = 0; i < indio_dev->num_channels; i++) {
+	for (i = 0; i < st->num_adc_chans; i++) {
 		ret = ad4170_set_channel_enable(st, i, false);
 		if (ret)
 			return ret;

@@ -2758,7 +2769,9 @@ static irqreturn_t ad4170_trigger_handler(int irq, void *p)
 		memcpy(&st->bounce_buffer[i++], st->rx_buf, ARRAY_SIZE(st->rx_buf));
 	}
 
-	iio_push_to_buffers(indio_dev, st->bounce_buffer);
+	iio_push_to_buffers_with_ts(indio_dev, st->bounce_buffer,
+				    sizeof(st->bounce_buffer),
+				    iio_get_time_ns(indio_dev));
 err_out:
 	iio_trigger_notify_done(indio_dev->trig);
 	return IRQ_HANDLED;