[PATCH v3 08/13] iio: adc: ad7091r: Enable internal vref if external vref is not supplied

[Marcelo Schmitt]

The ADC needs a voltage reference to work correctly.
Enable AD7091R internal voltage reference if no external vref is
supplied.

Signed-off-by: Marcelo Schmitt <marcelo.schmitt@xxxxxxxxxx>
---
 drivers/iio/adc/ad7091r-base.c | 9 ++++++---
 drivers/iio/adc/ad7091r-base.h | 1 +
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/iio/adc/ad7091r-base.c b/drivers/iio/adc/ad7091r-base.c
index f2cb638b8d77..59a7ec44955d 100644
--- a/drivers/iio/adc/ad7091r-base.c
+++ b/drivers/iio/adc/ad7091r-base.c
@@ -215,10 +215,13 @@ int ad7091r_probe(struct device *dev, const char *name,
 	iio_dev->channels = st->chip_info->channels;
 
 	st->vref = devm_regulator_get_optional(dev, "vref");
-	if (IS_ERR(st->vref)) {
-		if (PTR_ERR(st->vref) == -EPROBE_DEFER)
-			return -EPROBE_DEFER;
+	if (IS_ERR_OR_NULL(st->vref)) {
+		/* Enable internal vref */
 		st->vref = NULL;
+		ret = regmap_update_bits(st->map, AD7091R_REG_CONF,
+					 AD7091R_REG_CONF_INT_VREF, BIT(0));
+		if (ret)
+			return ret;
 	} else {
 		ret = regulator_enable(st->vref);
 		if (ret)
diff --git a/drivers/iio/adc/ad7091r-base.h b/drivers/iio/adc/ad7091r-base.h
index 9546d0bf1da7..e153c2d7deb5 100644
--- a/drivers/iio/adc/ad7091r-base.h
+++ b/drivers/iio/adc/ad7091r-base.h
@@ -20,6 +20,7 @@
 #define AD7091R_REG_CH_HYSTERESIS(ch) ((ch) * 3 + 6)
 
 /* AD7091R_REG_CONF */
+#define AD7091R_REG_CONF_INT_VREF	BIT(0)
 #define AD7091R_REG_CONF_ALERT_EN	BIT(4)
 #define AD7091R_REG_CONF_AUTO		BIT(8)
 #define AD7091R_REG_CONF_CMD		BIT(10)
-- 
2.42.0