Commit ceb4781b authored by Alexandre Belloni's avatar Alexandre Belloni Committed by Greg Kroah-Hartman

iio: mxs-lradc: Fix temperature offset

commit b94e2280 upstream.

0° Kelvin is actually −273.15°C, not -272.15°C. Fix the temperature offset.
Also improve the comment explaining the calculation.
Reported-by: default avatarJanusz Użycki <j.uzycki@elpromaelectronics.com>
Signed-off-by: default avatarAlexandre Belloni <alexandre.belloni@free-electrons.com>
Acked-by: default avatarStefan Wahren <stefan.wahren@i2se.com>
Acked-by: default avatarMarek Vasut <marex@denx.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarJonathan Cameron <jic23@kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 7fc59864
......@@ -920,11 +920,12 @@ static int mxs_lradc_read_raw(struct iio_dev *iio_dev,
case IIO_CHAN_INFO_OFFSET:
if (chan->type == IIO_TEMP) {
/* The calculated value from the ADC is in Kelvin, we
* want Celsius for hwmon so the offset is
* -272.15 * scale
* want Celsius for hwmon so the offset is -273.15
* The offset is applied before scaling so it is
* actually -213.15 * 4 / 1.012 = -1079.644268
*/
*val = -1075;
*val2 = 691699;
*val = -1079;
*val2 = 644268;
return IIO_VAL_INT_PLUS_MICRO;
}
......
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