| Message ID | 1634905169-23762-1-git-send-email-fabrice.gasnier@foss.st.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | iio: adc: stm32: fix a leak by resetting pcsel before disabling vdda | expand |
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 <fabrice.gasnier@foss.st.com> > --- > 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
On Fri, 22 Oct 2021 14:38:52 +0200 Olivier MOYSAN <olivier.moysan@foss.st.com> 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 <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. 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 <olivier.moysan@foss.st.com> > > Thanks > Olivier
On 10/24/21 6:07 PM, Jonathan Cameron wrote: > On Fri, 22 Oct 2021 14:38:52 +0200 > Olivier MOYSAN <olivier.moysan@foss.st.com> 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 <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 > >>> --- >>> 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 >
On Mon, 25 Oct 2021 09:43:10 +0200 Fabrice Gasnier <fabrice.gasnier@foss.st.com> wrote: > On 10/24/21 6:07 PM, Jonathan Cameron wrote: > > On Fri, 22 Oct 2021 14:38:52 +0200 > > Olivier MOYSAN <olivier.moysan@foss.st.com> 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 <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. 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 <olivier.moysan@foss.st.com> > >> > >> Thanks > >> Olivier > >
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); }
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> --- drivers/iio/adc/stm32-adc.c | 1 + 1 file changed, 1 insertion(+)