[PATCH v2 5/7] iio: adc: ti-ads1262: Add conversion delay support

[Kurt Borja <kuurtb@gmail.com>]

Expose the programmable conversion start delay as a per-channel
IIO_CHAN_INFO_CONVDELAY attribute.

Signed-off-by: Kurt Borja <kuurtb@gmail.com>
---
 drivers/iio/adc/ti-ads1262.c | 63 +++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 62 insertions(+), 1 deletion(-)

diff --git a/drivers/iio/adc/ti-ads1262.c b/drivers/iio/adc/ti-ads1262.c
index 8921eaae537f6b0a..4ae22c1b0b4b7d79 100644
--- a/drivers/iio/adc/ti-ads1262.c
+++ b/drivers/iio/adc/ti-ads1262.c
@@ -141,6 +141,21 @@
 #define ADS1262_MAX_CHANNEL_COUNT		16
 #define ADS1262_XFER_BUFFER_SZ			11
 
+enum {
+	ADS1262_DELAY_NO_DELAY,
+	ADS1262_DELAY_8700_NS,
+	ADS1262_DELAY_17_US,
+	ADS1262_DELAY_35_US,
+	ADS1262_DELAY_69_US,
+	ADS1262_DELAY_139_US,
+	ADS1262_DELAY_278_US,
+	ADS1262_DELAY_555_US,
+	ADS1262_DELAY_1100_US,
+	ADS1262_DELAY_2200_US,
+	ADS1262_DELAY_4400_US,
+	ADS1262_DELAY_8800_US,
+};
+
 enum {
 	ADS1262_RUNMODE_CONTINUOUS,
 	ADS1262_RUNMODE_PULSE,
@@ -225,6 +240,7 @@ struct ads1262_chip_info {
 
 struct ads1262_channel {
 	u8 input[2];
+	u8 delay;
 	u8 filter;
 	u8 gain;
 	u8 data_rate;
@@ -281,6 +297,21 @@ static const int ads1262_data_rate_avail[][2] = {
 	[ADS1262_DR_38400_SPS]	= { 38400,	0 },
 };
 
+static const int ads1262_conv_delay_avail[][2] = {
+	[ADS1262_DELAY_NO_DELAY]	= { 0, 0 },
+	[ADS1262_DELAY_8700_NS]		= { 0, 8700 },
+	[ADS1262_DELAY_17_US]		= { 0, 17000 },
+	[ADS1262_DELAY_35_US]		= { 0, 35000 },
+	[ADS1262_DELAY_69_US]		= { 0, 69000 },
+	[ADS1262_DELAY_139_US]		= { 0, 139000 },
+	[ADS1262_DELAY_278_US]		= { 0, 278000 },
+	[ADS1262_DELAY_555_US]		= { 0, 555000 },
+	[ADS1262_DELAY_1100_US]		= { 0, 1100000 },
+	[ADS1262_DELAY_2200_US]		= { 0, 2200000 },
+	[ADS1262_DELAY_4400_US]		= { 0, 4400000 },
+	[ADS1262_DELAY_8800_US]		= { 0, 8800000 },
+};
+
 static const int ads1262_pga_gain_avail[] = {
 	1, 2, 4, 8, 16, 32
 };
@@ -473,7 +504,8 @@ static int ads1262_channel_enable(struct ads1262 *st,
 
 	/* Avoid using guard() here to mitigate AB/BA deadlock warning */
 	mutex_lock(&st->chan_lock);
-	mode0 = FIELD_PREP(ADS1262_MODE0_INPUT_CHOP_MASK, chan->input_chop) |
+	mode0 = FIELD_PREP(ADS1262_MODE0_DELAY_MASK, chan->delay) |
+		FIELD_PREP(ADS1262_MODE0_INPUT_CHOP_MASK, chan->input_chop) |
 		FIELD_PREP(ADS1262_MODE0_IDAC_CHOP_MASK, chan->idac_chop) |
 		FIELD_PREP(ADS1262_MODE0_REFREV_MASK, chan->ref_reversal);
 	mode1 = FIELD_PREP(ADS1262_MODE1_FILTER_MASK, chan->filter);
@@ -491,6 +523,7 @@ static int ads1262_channel_enable(struct ads1262 *st,
 	mutex_unlock(&st->chan_lock);
 
 	ret = regmap_update_bits(st->regmap, ADS1262_MODE0_REG,
+				 ADS1262_MODE0_DELAY_MASK |
 				 ADS1262_MODE0_INPUT_CHOP_MASK |
 				 ADS1262_MODE0_IDAC_CHOP_MASK |
 				 ADS1262_MODE0_REFREV_MASK, mode0);
@@ -625,6 +658,15 @@ static int ads1262_read_raw(struct iio_dev *indio_dev,
 		return IIO_VAL_INT_PLUS_MICRO;
 	}
 
+	case IIO_CHAN_INFO_CONVDELAY: {
+		guard(mutex)(&st->chan_lock);
+
+		*val = ads1262_conv_delay_avail[chan_data->delay][0];
+		*val2 = ads1262_conv_delay_avail[chan_data->delay][1];
+
+		return IIO_VAL_INT_PLUS_NANO;
+	}
+
 	default:
 		return -EOPNOTSUPP;
 	}
@@ -647,6 +689,12 @@ static int ads1262_read_avail(struct iio_dev *indio_dev,
 		*length = ARRAY_SIZE(ads1262_pga_gain_avail);
 		return IIO_AVAIL_LIST;
 
+	case IIO_CHAN_INFO_CONVDELAY:
+		*type = IIO_VAL_INT_PLUS_NANO;
+		*vals = (const int *)ads1262_conv_delay_avail;
+		*length = ARRAY_SIZE(ads1262_conv_delay_avail) * 2;
+		return IIO_AVAIL_LIST;
+
 	default:
 		return -EOPNOTSUPP;
 	}
@@ -685,6 +733,17 @@ static int ads1262_write_raw(struct iio_dev *indio_dev,
 		break;
 	}
 
+	case IIO_CHAN_INFO_CONVDELAY: {
+		i = ads1262_find_two(ads1262_conv_delay_avail, val, val2);
+		if (i < 0)
+			return i;
+
+		guard(mutex)(&st->chan_lock);
+		chan_data->delay = i;
+
+		break;
+	}
+
 	default:
 		return -EOPNOTSUPP;
 	}
@@ -807,8 +866,10 @@ static int ads1262_alloc_channels(struct ads1262 *st,
 			.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
 					      BIT(IIO_CHAN_INFO_SCALE) |
 					      BIT(IIO_CHAN_INFO_HARDWAREGAIN) |
+					      BIT(IIO_CHAN_INFO_CONVDELAY) |
 					      BIT(IIO_CHAN_INFO_SAMP_FREQ),
 			.info_mask_shared_by_type_available =
+				BIT(IIO_CHAN_INFO_CONVDELAY) |
 				BIT(IIO_CHAN_INFO_HARDWAREGAIN) |
 				BIT(IIO_CHAN_INFO_SAMP_FREQ),
 			.indexed = true,

-- 
2.54.0