[PATCH 4.4 012/143] staging: iio: ad7780: update voltage on read

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

[ Upstream commit 336650c785b62c3bea7c8cf6061c933a90241f67 ]

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it read an outdated value set at initialization.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>
Acked-by: Alexandru Ardelean <alexandru.ardelean@xxxxxxxxxx>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 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 3abc7789237f..531338ea5eb4 100644
--- a/drivers/staging/iio/adc/ad7780.c
+++ b/drivers/staging/iio/adc/ad7780.c
@@ -90,12 +90,16 @@ 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 < 0)
+			return voltage_uv;
+		*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