* [PATCH v2] iio: mxs-lradc: Fix temperature offset
@ 2015-10-07 11:10 Alexandre Belloni
2015-10-07 15:07 ` Stefan Wahren
0 siblings, 1 reply; 3+ messages in thread
From: Alexandre Belloni @ 2015-10-07 11:10 UTC (permalink / raw)
To: Jonathan Cameron
Cc: Lars-Peter Clausen, Stefan Wahren, Janusz Użycki,
Marek Vasut, linux-iio, linux-kernel, Alexandre Belloni
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>
---
drivers/staging/iio/adc/mxs-lradc.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/drivers/staging/iio/adc/mxs-lradc.c b/drivers/staging/iio/adc/mxs-lradc.c
index 3f7715c9968b..47fc00a3f63b 100644
--- a/drivers/staging/iio/adc/mxs-lradc.c
+++ b/drivers/staging/iio/adc/mxs-lradc.c
@@ -915,11 +915,12 @@ 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;
}
--
2.1.4
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH v2] iio: mxs-lradc: Fix temperature offset
2015-10-07 11:10 [PATCH v2] iio: mxs-lradc: Fix temperature offset Alexandre Belloni
@ 2015-10-07 15:07 ` Stefan Wahren
2015-10-11 12:51 ` Jonathan Cameron
0 siblings, 1 reply; 3+ messages in thread
From: Stefan Wahren @ 2015-10-07 15:07 UTC (permalink / raw)
To: Alexandre Belloni, Jonathan Cameron
Cc: Lars-Peter Clausen, Janusz Użycki, Marek Vasut, linux-iio,
linux-kernel
Am 07.10.2015 um 13:10 schrieb Alexandre Belloni:
> 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>
Thanks
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH v2] iio: mxs-lradc: Fix temperature offset
2015-10-07 15:07 ` Stefan Wahren
@ 2015-10-11 12:51 ` Jonathan Cameron
0 siblings, 0 replies; 3+ messages in thread
From: Jonathan Cameron @ 2015-10-11 12:51 UTC (permalink / raw)
To: Stefan Wahren, Alexandre Belloni
Cc: Lars-Peter Clausen, Janusz Użycki, Marek Vasut, linux-iio,
linux-kernel
On 07/10/15 16:07, Stefan Wahren wrote:
> Am 07.10.2015 um 13:10 schrieb Alexandre Belloni:
>> 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>
Applied to the fixes-togreg branch of iio.git and
marked for stable.
Thanks,
Jonathan
>
> Thanks
> --
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^ permalink raw reply [flat|nested] 3+ messages in thread
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2015-10-07 15:07 ` Stefan Wahren
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