6.17-stable review patch. If anyone has any objections, please let me know.
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From: David Lechner dlechner@baylibre.com
commit e2cc390a6629c76924a2740c54b144b9b28fca59 upstream.
Fix temperature channel not working due to gain and offset not being initialized. For channels other than the voltage ones calibration is skipped (which is OK). However that results in the calibration register values tracked in st->channels[i].cfg all being zero. These zeros are later written to hardware before a measurement is made which caused the raw temperature readings to be always 8388608 (0x800000).
To fix it, we just make sure the gain and offset values are set to the default values and still return early without doing an internal calibration.
While here, add a comment explaining why we don't bother calibrating the temperature channel.
Fixes: 47036a03a303 ("iio: adc: ad7124: Implement internal calibration at probe time") Reviewed-by: Marcelo Schmitt marcelo.schmitt@analog.com Signed-off-by: David Lechner dlechner@baylibre.com Reviewed-by: Uwe Kleine-König u.kleine-koenig@baylibre.com Cc: Stable@vger.kernel.org Signed-off-by: Jonathan Cameron Jonathan.Cameron@huawei.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/iio/adc/ad7124.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-)
--- a/drivers/iio/adc/ad7124.c +++ b/drivers/iio/adc/ad7124.c @@ -1196,10 +1196,6 @@ static int __ad7124_calibrate_all(struct int ret, i;
for (i = 0; i < st->num_channels; i++) { - - if (indio_dev->channels[i].type != IIO_VOLTAGE) - continue; - /* * For calibration the OFFSET register should hold its reset default * value. For the GAIN register there is no such requirement but @@ -1210,6 +1206,14 @@ static int __ad7124_calibrate_all(struct st->channels[i].cfg.calibration_gain = st->gain_default;
/* + * Only the main voltage input channels are important enough + * to be automatically calibrated here. For everything else, + * just use the default values set above. + */ + if (indio_dev->channels[i].type != IIO_VOLTAGE) + continue; + + /* * Full-scale calibration isn't supported at gain 1, so skip in * that case. Note that untypically full-scale calibration has * to happen before zero-scale calibration. This only applies to