[PATCH 3/3] iio: adc: mt6359-auxadc: fix scale calculation

[Roman Vivchar via B4 Relay]

From: Roman Vivchar <rva333@xxxxxxxxxxxxxx>

IIO_CHAN_INFO_SCALE currently returns value without dividing by
2^realbits, overflowing the integer to an invalid value.

Fix this by using IIO_VAL_FRACTIONAL and setting val2 to the ADC
resolution.

Fixes: 3587914bf61d ("iio: adc: Add support for MediaTek MT6357/8/9 Auxiliary ADC")
Signed-off-by: Roman Vivchar <rva333@xxxxxxxxxxxxxx>
---
 drivers/iio/adc/mt6359-auxadc.c | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/drivers/iio/adc/mt6359-auxadc.c b/drivers/iio/adc/mt6359-auxadc.c
index 09432d0974cf..3a969c30f633 100644
--- a/drivers/iio/adc/mt6359-auxadc.c
+++ b/drivers/iio/adc/mt6359-auxadc.c
@@ -770,13 +770,9 @@ static int mt6359_auxadc_read_raw(struct iio_dev *indio_dev,
 
 	if (mask == IIO_CHAN_INFO_SCALE) {
 		*val = desc->r_ratio.numerator * cinfo->vref_mV;
+		*val2 = desc->r_ratio.denominator << chan->scan_type.realbits;
 
-		if (desc->r_ratio.denominator > 1) {
-			*val2 = desc->r_ratio.denominator;
-			return IIO_VAL_FRACTIONAL;
-		}
-
-		return IIO_VAL_INT;
+		return IIO_VAL_FRACTIONAL;
 	}
 
 	scoped_guard(mutex, &adc_dev->lock) {

-- 
2.56.0