iio: mxs-lradc: Fix temperature offset
0° Kelvin is actually −273.15°C, not -272.15°C. Fix the temperature offset. Also improve the comment explaining the calculation. Reported-by: Janusz Użycki <j.uzycki@elpromaelectronics.com> Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com> Acked-by: Stefan Wahren <stefan.wahren@i2se.com> Acked-by: Marek Vasut <marex@denx.de> Cc: <stable@vger.kernel.org> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
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@ -915,11 +915,12 @@ static int mxs_lradc_read_raw(struct iio_dev *iio_dev,
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case IIO_CHAN_INFO_OFFSET:
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case IIO_CHAN_INFO_OFFSET:
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if (chan->type == IIO_TEMP) {
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if (chan->type == IIO_TEMP) {
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/* The calculated value from the ADC is in Kelvin, we
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/* The calculated value from the ADC is in Kelvin, we
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* want Celsius for hwmon so the offset is
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* want Celsius for hwmon so the offset is -273.15
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* -272.15 * scale
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* The offset is applied before scaling so it is
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* actually -213.15 * 4 / 1.012 = -1079.644268
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*/
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*/
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*val = -1075;
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*val = -1079;
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*val2 = 691699;
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*val2 = 644268;
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return IIO_VAL_INT_PLUS_MICRO;
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return IIO_VAL_INT_PLUS_MICRO;
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}
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}
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