On Mon, 14 Mar 2022 at 15:34, Yann Gautier <yann.gautier@xxxxxxxxxxx> wrote: > > On 3/14/22 14:03, Ulf Hansson wrote: > > On Mon, 14 Mar 2022 at 13:56, Yann Gautier <yann.gautier@xxxxxxxxxxx> 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 <yann.gautier@xxxxxxxxxxx> > >> --- > >> 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/20220304135134.47827-1-yann.gautier@xxxxxxxxxxx/ > >> > >> 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 > >> >
