On 3/14/22 14:03, Ulf Hansson wrote:
> On Mon, 14 Mar 2022 at 13:56, Yann Gautier <[email protected]> wrote:
>>
>> Add a disable_keep_power field in variant_data struct. The
>> MMC_PM_KEEP_POWER flag will be enabled if disable_keep_power is not set.
>> It is only set to true for stm32_sdmmc variants.
>>
>> The issue was seen on STM32MP157C-DK2 board, which embeds a wifi chip.
>> It doesn't correctly support low power on this board. The Wifi chip
>> awaits an always-on regulator, but it was connected to v3v3 which is off
>> in low-power sequence. MMC_PM_KEEP_POWER should then be disabled.
>
> Just to make sure I get this correct.
>
> Why can't the regulator stay on during system suspend? The point is,
> we don't need an always on regulator to cope with this.
>
> Kind regards
> Uffe
Hi Ulf,
This v3v3 regulator powers most of the devices on this board. So we need
to switch it off to gain power in suspend mode.
Yann
>
>>
>> The flag can still be enabled through DT property:
>> keep-power-in-suspend.
>>
>> Signed-off-by: Yann Gautier <[email protected]>
>> ---
>> Update in v2:
>> Reword commit message to better explain the issue.
>>
>> Resend the patch alone. It was previoulsy in a series [1] for which the
>> other patches will be reworked.
>>
>> [1] https://lore.kernel.org/lkml/[email protected]/
>>
>> drivers/mmc/host/mmci.c | 5 ++++-
>> drivers/mmc/host/mmci.h | 1 +
>> 2 files changed, 5 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/mmc/host/mmci.c b/drivers/mmc/host/mmci.c
>> index 45b8608c935c..0e2f2f5d6a52 100644
>> --- a/drivers/mmc/host/mmci.c
>> +++ b/drivers/mmc/host/mmci.c
>> @@ -274,6 +274,7 @@ static struct variant_data variant_stm32_sdmmc = {
>> .busy_detect = true,
>> .busy_detect_flag = MCI_STM32_BUSYD0,
>> .busy_detect_mask = MCI_STM32_BUSYD0ENDMASK,
>> + .disable_keep_power = true,
>> .init = sdmmc_variant_init,
>> };
>>
>> @@ -301,6 +302,7 @@ static struct variant_data variant_stm32_sdmmcv2 = {
>> .busy_detect = true,
>> .busy_detect_flag = MCI_STM32_BUSYD0,
>> .busy_detect_mask = MCI_STM32_BUSYD0ENDMASK,
>> + .disable_keep_power = true,
>> .init = sdmmc_variant_init,
>> };
>>
>> @@ -2172,7 +2174,8 @@ static int mmci_probe(struct amba_device *dev,
>> host->stop_abort.flags = MMC_RSP_R1B | MMC_CMD_AC;
>>
>> /* We support these PM capabilities. */
>> - mmc->pm_caps |= MMC_PM_KEEP_POWER;
>> + if (!variant->disable_keep_power)
>> + mmc->pm_caps |= MMC_PM_KEEP_POWER;
>>
>> /*
>> * We can do SGIO
>> diff --git a/drivers/mmc/host/mmci.h b/drivers/mmc/host/mmci.h
>> index e1a9b96a3396..2cad1ef9766a 100644
>> --- a/drivers/mmc/host/mmci.h
>> +++ b/drivers/mmc/host/mmci.h
>> @@ -361,6 +361,7 @@ struct variant_data {
>> u32 opendrain;
>> u8 dma_lli:1;
>> u32 stm32_idmabsize_mask;
>> + u8 disable_keep_power:1;
>> void (*init)(struct mmci_host *host);
>> };
>>
>> --
>> 2.25.1
>>
On Mon, 14 Mar 2022 at 15:34, Yann Gautier <[email protected]> wrote:
>
> On 3/14/22 14:03, Ulf Hansson wrote:
> > On Mon, 14 Mar 2022 at 13:56, Yann Gautier <[email protected]> wrote:
> >>
> >> Add a disable_keep_power field in variant_data struct. The
> >> MMC_PM_KEEP_POWER flag will be enabled if disable_keep_power is not set.
> >> It is only set to true for stm32_sdmmc variants.
> >>
> >> The issue was seen on STM32MP157C-DK2 board, which embeds a wifi chip.
> >> It doesn't correctly support low power on this board. The Wifi chip
> >> awaits an always-on regulator, but it was connected to v3v3 which is off
> >> in low-power sequence. MMC_PM_KEEP_POWER should then be disabled.
> >
> > Just to make sure I get this correct.
> >
> > Why can't the regulator stay on during system suspend? The point is,
> > we don't need an always on regulator to cope with this.
> >
> > Kind regards
> > Uffe
>
> Hi Ulf,
>
> This v3v3 regulator powers most of the devices on this board. So we need
> to switch it off to gain power in suspend mode.
I see. Thanks for sharing that information.
The MMC_PM_KEEP_POWER flag is there to describe what is supported by
the platform/host. It doesn't mean that the card *must* stay powered
on during system suspend. Instead that depends on whether system
wakeup for the SDIO/WiFi is supported too - and if that is enabled by
userspace. If not, the regulator will be turned off for the SDIO card
during system suspend.
Assuming the regulator is implemented as a proper regulator and can
remain on during system suspend, the right thing would be to keep the
MMC_PM_KEEP_POWER flag around.
Kind regards
Uffe
>
>
> Yann
>
> >
> >>
> >> The flag can still be enabled through DT property:
> >> keep-power-in-suspend.
> >>
> >> Signed-off-by: Yann Gautier <[email protected]>
> >> ---
> >> Update in v2:
> >> Reword commit message to better explain the issue.
> >>
> >> Resend the patch alone. It was previoulsy in a series [1] for which the
> >> other patches will be reworked.
> >>
> >> [1] https://lore.kernel.org/lkml/[email protected]/
> >>
> >> drivers/mmc/host/mmci.c | 5 ++++-
> >> drivers/mmc/host/mmci.h | 1 +
> >> 2 files changed, 5 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/drivers/mmc/host/mmci.c b/drivers/mmc/host/mmci.c
> >> index 45b8608c935c..0e2f2f5d6a52 100644
> >> --- a/drivers/mmc/host/mmci.c
> >> +++ b/drivers/mmc/host/mmci.c
> >> @@ -274,6 +274,7 @@ static struct variant_data variant_stm32_sdmmc = {
> >> .busy_detect = true,
> >> .busy_detect_flag = MCI_STM32_BUSYD0,
> >> .busy_detect_mask = MCI_STM32_BUSYD0ENDMASK,
> >> + .disable_keep_power = true,
> >> .init = sdmmc_variant_init,
> >> };
> >>
> >> @@ -301,6 +302,7 @@ static struct variant_data variant_stm32_sdmmcv2 = {
> >> .busy_detect = true,
> >> .busy_detect_flag = MCI_STM32_BUSYD0,
> >> .busy_detect_mask = MCI_STM32_BUSYD0ENDMASK,
> >> + .disable_keep_power = true,
> >> .init = sdmmc_variant_init,
> >> };
> >>
> >> @@ -2172,7 +2174,8 @@ static int mmci_probe(struct amba_device *dev,
> >> host->stop_abort.flags = MMC_RSP_R1B | MMC_CMD_AC;
> >>
> >> /* We support these PM capabilities. */
> >> - mmc->pm_caps |= MMC_PM_KEEP_POWER;
> >> + if (!variant->disable_keep_power)
> >> + mmc->pm_caps |= MMC_PM_KEEP_POWER;
> >>
> >> /*
> >> * We can do SGIO
> >> diff --git a/drivers/mmc/host/mmci.h b/drivers/mmc/host/mmci.h
> >> index e1a9b96a3396..2cad1ef9766a 100644
> >> --- a/drivers/mmc/host/mmci.h
> >> +++ b/drivers/mmc/host/mmci.h
> >> @@ -361,6 +361,7 @@ struct variant_data {
> >> u32 opendrain;
> >> u8 dma_lli:1;
> >> u32 stm32_idmabsize_mask;
> >> + u8 disable_keep_power:1;
> >> void (*init)(struct mmci_host *host);
> >> };
> >>
> >> --
> >> 2.25.1
> >>
>