commit f711f28e71e965c0d1141c830fa7131b41abbe75 upstream.

Some I/Os are connected to ADC input channels, when the corresponding bit in PCSEL register are set on STM32H7 and STM32MP15. This is done in the prepare routine of stm32-adc driver. There are constraints here, as PCSEL shouldn't be set when VDDA supply is disabled. Enabling/disabling of VDDA supply in done via stm32-adc-core runtime PM routines (before/after ADC is enabled/disabled).

Currently, PCSEL remains set when disabling ADC. Later on, PM runtime can disable the VDDA supply. This creates some conditions on I/Os that can start to leak current. So PCSEL needs to be cleared when disabling the ADC.

Fixes: 95e339b6e85d ("iio: adc: stm32: add support for STM32H7") Signed-off-by: Fabrice Gasnier fabrice.gasnier@foss.st.com Reviewed-by: Olivier Moysan olivier.moysan@foss.st.com Link: https://lore.kernel.org/r/1634905169-23762-1-git-send-email-fabrice.gasnier@... Cc: Stable@vger.kernel.org Signed-off-by: Jonathan Cameron Jonathan.Cameron@huawei.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- Backport for 5.4-stable --- drivers/iio/adc/stm32-adc.c | 1 + 1 file changed, 1 insertion(+)

diff --git a/drivers/iio/adc/stm32-adc.c b/drivers/iio/adc/stm32-adc.c index 94fde39..d1bbd2b 100644 --- a/drivers/iio/adc/stm32-adc.c +++ b/drivers/iio/adc/stm32-adc.c @@ -933,6 +933,7 @@ static int stm32h7_adc_prepare(struct stm32_adc *adc)

static void stm32h7_adc_unprepare(struct stm32_adc *adc) { + stm32_adc_writel(adc, STM32H7_ADC_PCSEL, 0); stm32h7_adc_disable(adc); stm32h7_adc_enter_pwr_down(adc); }