[PATCH v3 2/3] staging: iio: ad7780: update voltage on read

[Renato Lui Geh <renatogeh@xxxxxxxxx>]

The ad7780 driver previously did not read the correct device output, as
it read an outdated value set at initialization. It now updates its
voltage on read.

Signed-off-by: Renato Lui Geh <renatogeh@xxxxxxxxx>
---
Changes in v3:
	- removed initialization (int voltage_uv = 0)
	- returns error when voltage_uv is null

drivers/staging/iio/adc/ad7780.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/staging/iio/adc/ad7780.c b/drivers/staging/iio/adc/ad7780.c
index 91e016d534ed..f2a11e9424cd 100644
--- a/drivers/staging/iio/adc/ad7780.c
+++ b/drivers/staging/iio/adc/ad7780.c
@@ -87,12 +87,16 @@ static int ad7780_read_raw(struct iio_dev *indio_dev,
			   long m)
{
	struct ad7780_state *st = iio_priv(indio_dev);
+	int voltage_uv;

	switch (m) {
	case IIO_CHAN_INFO_RAW:
		return ad_sigma_delta_single_conversion(indio_dev, chan, val);
	case IIO_CHAN_INFO_SCALE:
-		*val = st->int_vref_mv * st->gain;
+		voltage_uv = regulator_get_voltage(st->reg);
+		if (!voltage_uv)
+			return -EINVAL;
+		*val = (voltage_uv / 1000) * st->gain;
		*val2 = chan->scan_type.realbits - 1;
		return IIO_VAL_FRACTIONAL_LOG2;
	case IIO_CHAN_INFO_OFFSET:
--
2.19.1