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 <[email protected]>
---
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);
}
--
2.7.4
Hi Fabrice,
On 10/22/21 2:19 PM, Fabrice Gasnier wrote:
> 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 <[email protected]>
> ---
> 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 <[email protected]>
Thanks
Olivier
On Fri, 22 Oct 2021 14:38:52 +0200
Olivier MOYSAN <[email protected]> wrote:
I'll probably reword the description here as 'leak' tends to mean memory
leak rather than current.
> Hi Fabrice,
>
> On 10/22/21 2:19 PM, Fabrice Gasnier wrote:
> > 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.
> > Signed-off-by: Fabrice Gasnier <[email protected]>
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.
Jonathan
> > ---
> > 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 <[email protected]>
>
> Thanks
> Olivier
On 10/24/21 6:07 PM, Jonathan Cameron wrote:
> On Fri, 22 Oct 2021 14:38:52 +0200
> Olivier MOYSAN <[email protected]> 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.
>
>> Hi Fabrice,
>>
>> On 10/22/21 2:19 PM, Fabrice Gasnier wrote:
>>> 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.
>>> Signed-off-by: Fabrice Gasnier <[email protected]>
>
> 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
>
>>> ---
>>> 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 <[email protected]>
>>
>> Thanks
>> Olivier
>
On Mon, 25 Oct 2021 09:43:10 +0200
Fabrice Gasnier <[email protected]> wrote:
> On 10/24/21 6:07 PM, Jonathan Cameron wrote:
> > On Fri, 22 Oct 2021 14:38:52 +0200
> > Olivier MOYSAN <[email protected]> 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.
Added the word current to the title which I think makes it clear.
>
> >
> >> Hi Fabrice,
> >>
> >> On 10/22/21 2:19 PM, Fabrice Gasnier wrote:
> >>> 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.
>
> >>> Signed-off-by: Fabrice Gasnier <[email protected]>
> >
> > 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.
Applied to the fixes-togreg branch of iio.git, targeting a pull request
some time shortly after rc1.
Thanks,
Jonathan
>
> Many thanks,
> Fabrice
> >
> > Jonathan
> >
> >>> ---
> >>> 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 <[email protected]>
> >>
> >> Thanks
> >> Olivier
> >