From 7243aa71509a83409bf5a086ea24f029afb7bb69 Mon Sep 17 00:00:00 2001 From: Fabrice Gasnier Date: Fri, 22 Oct 2021 14:19:29 +0200 Subject: [PATCH] iio: adc: stm32: fix a current leak by resetting pcsel before disabling vdda 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 Reviewed-by: Olivier Moysan Link: https://lore.kernel.org/r/1634905169-23762-1-git-send-email-fabrice.gasnier@foss.st.com Cc: Signed-off-by: Jonathan Cameron Signed-off-by: Greg Kroah-Hartman --- 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 94fde39d9ff7..d1bbd2b197fc 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); }