[PATCH 2/2] iio: addac: ad74413r: wire up digital-input-threshold-microvolt DT property

[Rasmus Villemoes <linux@rasmusvillemoes.dk>]

The threshold is common to all channels configured as digital
input.

So far, we have not seen the settings in the DIN_THRESH affecting
functions other than digital input, but with a4cba07e64e6 ("iio:
addac: ad74413: don't set DIN_SINK for functions other than digital
input") in mind, do not read and apply the
digital-input-threshold-microvolt setting unless at least one channel
has been configured as one of the digital input variants.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
---
 drivers/iio/addac/ad74413r.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/drivers/iio/addac/ad74413r.c b/drivers/iio/addac/ad74413r.c
index e3366cf5eb31..efdd7fdd7ab9 100644
--- a/drivers/iio/addac/ad74413r.c
+++ b/drivers/iio/addac/ad74413r.c
@@ -129,6 +129,12 @@ struct ad74413r_state {
 #define AD74413R_GPO_CONFIG_COMPARATOR		0b011
 #define AD74413R_GPO_CONFIG_HIGH_IMPEDANCE	0b100
 
+#define AD74413R_REG_DIN_THRESH		0x22
+#define AD74413R_DIN_COMP_THRESH_MASK	GENMASK(5, 1)
+#define AD74413R_DIN_THRESH_MODE	BIT(0)
+#define AD74413R_DIN_THRESH_MODE_16V	BIT(0)
+#define AD74413R_DIN_THRESH_MODE_AVDD	0
+
 #define AD74413R_REG_ADC_CONV_CTRL	0x23
 #define AD74413R_CONV_SEQ_MASK		GENMASK(9, 8)
 #define AD74413R_CONV_SEQ_ON		0b00
@@ -1446,6 +1452,20 @@ static int ad74413r_probe(struct spi_device *spi)
 	}
 
 	if (st->num_comparator_gpios) {
+		u32 thresh, val, mask;
+
+		if (!device_property_read_u32(st->dev, "digital-input-threshold-microvolt",
+					      &thresh)) {
+			val = thresh/500000 - 1;
+			val = FIELD_PREP(AD74413R_DIN_COMP_THRESH_MASK, val);
+			val |= AD74413R_DIN_THRESH_MODE_16V;
+			mask = AD74413R_DIN_COMP_THRESH_MASK | AD74413R_DIN_THRESH_MODE;
+			ret = regmap_update_bits(st->regmap, AD74413R_REG_DIN_THRESH,
+						 mask, val);
+			if (ret)
+				return ret;
+		}
+
 		st->comp_gpiochip.owner = THIS_MODULE;
 		st->comp_gpiochip.label = st->chip_info->name;
 		st->comp_gpiochip.base = -1;
-- 
2.37.2