On 10/24/21 6:07 PM, Jonathan Cameron wrote:

On Fri, 22 Oct 2021 14:38:52 +0200
Olivier MOYSAN [off-list ref] wrote:

I'll probably reword the description here as 'leak' tends to mean memory
leak rather than current.

Hi Jonathan,

Yes, please fell free to improve this. I had the same concern, but I
haven't found a more suitable description.

quoted

Hi Fabrice,

On 10/22/21 2:19 PM, Fabrice Gasnier wrote:

quoted

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")

No line break here as Fixes forms part of the tag block.

Sorry, will check this next time.

quoted

quoted

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>

Given timing wrt to being too near merge window, I'll let this it on
list a while longer as it'll be post rc1 material now anyway.

I can fix the above whilst applying if nothing else comes up.

That's fine for me.

Many thanks,
Fabrice

Jonathan

quoted

quoted

---
  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 5088de8..e3e7541 100644
--- a/drivers/iio/adc/stm32-adc.c
+++ b/drivers/iio/adc/stm32-adc.c

@@ -975,6 +975,7 @@ static void stm32h7_adc_unprepare(struct iio_dev *indio_dev)
  {
  	struct stm32_adc *adc = iio_priv(indio_dev);
  
+	stm32_adc_writel(adc, STM32H7_ADC_PCSEL, 0);
  	stm32h7_adc_disable(indio_dev);
  	stm32h7_adc_enter_pwr_down(adc);
  }
  

Reviewed-by: Olivier Moysan <olivier.moysan@foss.st.com>

Thanks
Olivier

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