Commit 883f50ea authored by Olivier Moysan's avatar Olivier Moysan Committed by Jonathan Cameron
Browse files

iio: adc: stm32-adc: disable adc before calibration 



The calibration is launched from prepare callback.
The ADC state when entering this function may be unknown as the
ADC may have been left enabled by boot stage.
One prerequisite for ADC calibration is to have ADC in disabled state.
If the calibration is started when ADC is still enabled, the behavior is
unpredictable, and the calibration may fail with a timeout error.

Force ADC to disabled state in stm32h7_adc_selfcalib().
ADC enabling is ensured by stm32h7_adc_enable() call,
before leaving prepare callback.

Signed-off-by: default avatarOlivier Moysan <olivier.moysan@foss.st.com>
Reviewed-by: default avatarFabrice Gasnier <fabrice.gasnier@foss.st.com>
Link: https://lore.kernel.org/r/20220620154738.801706-3-olivier.moysan@foss.st.com


Signed-off-by: default avatarJonathan Cameron <Jonathan.Cameron@huawei.com>
parent cf59ad96

drivers/iio/adc/stm32-adc.c

+3 −0
Original line number Diff line number Diff line
@@ -1019,6 +1019,9 @@ static int stm32h7_adc_selfcalib(struct iio_dev *indio_dev) 
	if (adc->cal.calibrated)

		return true;



	/* ADC must be disabled for calibration */

	stm32h7_adc_disable(indio_dev);



	/*

	 * Select calibration mode:

	 * - Offset calibration for single ended inputs