[PATCH v4 09/15] 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 | 7 +++++++
 drivers/iio/adc/ad7091r-base.h | 1 +
 2 files changed, 8 insertions(+)

diff --git a/drivers/iio/adc/ad7091r-base.c b/drivers/iio/adc/ad7091r-base.c
index aead72ef55b6..9d0b489966f5 100644
--- a/drivers/iio/adc/ad7091r-base.c
+++ b/drivers/iio/adc/ad7091r-base.c
@@ -217,7 +217,14 @@ int ad7091r_probe(struct device *dev, const struct ad7091r_init_info *init_info,
 	if (IS_ERR(st->vref)) {
 		if (PTR_ERR(st->vref) == -EPROBE_DEFER)
 			return -EPROBE_DEFER;
+
 		st->vref = NULL;
+		/* Enable internal vref */
+		ret = regmap_update_bits(st->map, AD7091R_REG_CONF,
+					 AD7091R_REG_CONF_INT_VREF, BIT(0));
+		if (ret)
+			return dev_err_probe(st->dev, ret,
+					     "Error on enable internal reference\n");
 	} 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 81b8a4bbb929..9cfb362a00a4 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