Re: [PATCH] mmc: rtsx: add card power off during probe

[micky]

On 09/17/2014 02:01 AM, Ulf Hansson wrote:
> On 12 September 2014 03:39,  <micky_ching@xxxxxxxxxxxxxx> wrote:
> > From: Roger Tseng <rogerable@xxxxxxxxxxx>
> >
> > Some platform have both UEFI driver and MFD/mmc driver, if entering
> > linux while card in the slot, the card power is already on, and rtsx-mmc
> > driver have no chance to make card power off. This will lead UHSI card
> > failed to enter UHSI mode.
> >
> > It is hard to control the UEFI driver leaving state, so we power off the
> > card power during probe.
> >
> > Signed-off-by: Roger Tseng <rogerable@xxxxxxxxxxx>
> > Signed-off-by: Micky Ching <micky_ching@xxxxxxxxxxxxxx>
> > ---
> >   drivers/mmc/host/rtsx_pci_sdmmc.c |    7 ++++++-
> >   1 file changed, 6 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/mmc/host/rtsx_pci_sdmmc.c b/drivers/mmc/host/rtsx_pci_sdmmc.c
> > index dfde4a2..57b0796 100644
> > --- a/drivers/mmc/host/rtsx_pci_sdmmc.c
> > +++ b/drivers/mmc/host/rtsx_pci_sdmmc.c
> > @@ -1341,8 +1341,13 @@ static int rtsx_pci_sdmmc_drv_probe(struct platform_device *pdev)
> >          host->pcr = pcr;
> >          host->mmc = mmc;
> >          host->pdev = pdev;
> > -       host->power_state = SDMMC_POWER_OFF;
> >          INIT_WORK(&host->work, sd_request);
> > +       sd_power_off(host);
> > +       /*
> > +        * ref: SD spec 3.01: 6.4.1.2 Power On or Power Cycle
> > +        */
> > +       usleep_range(1000, 2000);
> > +
> This won't work in cases were you power off eMMC cards, unless you can
> do a full power cycle - cut both VCC and VCCQ. Can you?
Hi Uffe,

VCCQ will poweroff at the same time.

if MMC_CAP2_NO_PRESCAN_POWERUP enable, will call mmc_power_off() at start,
then it will check ios.power_mode, but the state is MMC_POWER_OFF and just return.

Best Regards.
micky.

> There are also another option you might want to use,
> MMC_CAP2_NO_PRESCAN_POWERUP. But again, it must only be used for those
> hosts that you are able to do a full power cycle for.
>
> Kind regards
> Uffe
>
> >          platform_set_drvdata(pdev, host);
> >          pcr->slots[RTSX_SD_CARD].p_dev = pdev;
> >          pcr->slots[RTSX_SD_CARD].card_event = rtsx_pci_sdmmc_card_event;
> > --
> > 1.7.9.5
> .

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