[PATCH] staging: iio: ad7780: update voltage on read

[Renato Lui Geh <renatogeh@xxxxxxxxx>]

The ad7780 driver previously did not read the correct device output.
This patch fixes two issues.

- The driver read an outdated value set at initialization. It now
updates its voltage on read.
- Variable val subtracted an uninitialized value on
IIO_CHAN_INFO_OFFSET. This was fixed by assiging the correct value
instead.

Signed-off-by: Renato Lui Geh <renatogeh@xxxxxxxxx>
---
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 b67412db0318..06700fe554a2 100644
--- a/drivers/staging/iio/adc/ad7780.c
+++ b/drivers/staging/iio/adc/ad7780.c
@@ -87,16 +87,20 @@ static int ad7780_read_raw(struct iio_dev *indio_dev,
			   long m)
{
	struct ad7780_state *st = iio_priv(indio_dev);
+	int voltage_uv = 0;

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

--
2.19.1