summaryrefslogtreecommitdiff
path: root/drivers
diff options
context:
space:
mode:
authorAlexandre Belloni <alexandre.belloni@free-electrons.com>2015-10-07 13:10:54 +0200
committerSasha Levin <sasha.levin@oracle.com>2015-11-15 12:51:49 -0500
commit5b5ca1505596fe6906587ba22d85881cd7c57725 (patch)
tree70fff97dc3014f38a6ad819e7723acbd24ee719f /drivers
parent0a1bf5fd80e14a2396c6991d78b544ece3edf488 (diff)
iio: mxs-lradc: Fix temperature offset
[ Upstream commit b94e22805a2224061bb263a82b72e09544a5fbb3 ] 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> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/staging/iio/adc/mxs-lradc.c9
1 files changed, 5 insertions, 4 deletions
diff --git a/drivers/staging/iio/adc/mxs-lradc.c b/drivers/staging/iio/adc/mxs-lradc.c
index ffd42071a12e..6050c58db682 100644
--- a/drivers/staging/iio/adc/mxs-lradc.c
+++ b/drivers/staging/iio/adc/mxs-lradc.c
@@ -910,11 +910,12 @@ 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;
}