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Date:   Mon, 5 Nov 2018 17:14:58 -0200
From:   Renato Lui Geh <renatogeh@gmail.com>
To:     lars@metafoo.de, Michael.Hennerich@analog.com, jic23@kernel.org,
        knaack.h@gmx.de, pmeerw@pmeerw.net, gregkh@linuxfoundation.org,
        giuliano.belinassi@usp.br
Cc:     linux-iio@vger.kernel.org, devel@driverdev.osuosl.org,
        linux-kernel@vger.kernel.org, kernel-usp@googlegroups.com
Subject: [PATCH v4 1/2] staging: iio: ad7780: update voltage on read
Message-ID: <4b47bd8f4bac2575b72529b37e5ac90bebae2446.1541444377.git.renatogeh@gmail.com>
References: <cover.1541444377.git.renatogeh@gmail.com>
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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it read an outdated value set at initialization.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@gmail.com>
---
Changes in v3:
	- removed initialization (int voltage_uv = 0)
	- returns error when voltage_uv is null
Changes in v4:
	- returns error when voltage_uv is negative

 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..c7cb05cedbbc 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 < 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