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References: <20240415070620.133143-1-richard.xnu.clark@gmail.com> <52c08a01-8357-44dd-b727-a06438ec6c30@intel.com>
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From: richard clark <richard.xnu.clark@gmail.com>
Date: Mon, 15 Apr 2024 16:11:56 +0800
Message-ID: <CAJNi4rOyuXdHOifib6kX0Wdb5O5LXPEm9nsvEMe-jbCz9GyQww@mail.gmail.com>
Subject: Re: [PATCH] sdhci: Fix SD card detection issue
To: Adrian Hunter <adrian.hunter@intel.com>
Cc: ulf.hansson@linaro.org, linux-mmc@vger.kernel.org, 
	linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org
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On Mon, Apr 15, 2024 at 3:18=E2=80=AFPM Adrian Hunter <adrian.hunter@intel.=
com> wrote:
>
> On 15/04/24 10:06, Richard Clark wrote:
> > The mmc_gpio_get_cd(...) will return 0 called from sdhci_get_cd(...), w=
hich means
> > the card is not present. Actually, the card detection pin is active low=
 by default
> > according to the SDHCI psec, thus the card detection result is not corr=
ect, more
>
> SDHCI spec covers the SDHCI lines.  GPIO is separate.
>
> > specificly below if condition is true in mmc_rescan(...):
> >       ...
> >       if (mmc_card_is_removable(host) && host->ops->get_cd &&
> >               host->ops->get_cd(host) =3D=3D 0) {
> >               ...
> >               goto out;
> >       }
> > The SD card device will have no chance to be created.
> >
> > This commit fixes this detection issue via the MMC_CAP2_CD_ACTIVE_HIGH =
cap2 flag,
> > parsed from the 'cd-inverted' property of DT.
>
> What hardware / driver is it?
sdhci-tegra on Orin.
> >
> > Signed-off-by: Richard Clark <richard.xnu.clark@gmail.com>
> > ---
> >  drivers/mmc/host/sdhci.c | 3 +++
> >  1 file changed, 3 insertions(+)
> >
> > diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> > index c79f73459915..79f33a161ca8 100644
> > --- a/drivers/mmc/host/sdhci.c
> > +++ b/drivers/mmc/host/sdhci.c
> > @@ -2483,6 +2483,9 @@ static int sdhci_get_cd(struct mmc_host *mmc)
> >        * Try slot gpio detect, if defined it take precedence
> >        * over build in controller functionality
> >        */
> > +     if (!(mmc->caps2 & MMC_CAP2_CD_ACTIVE_HIGH))
> > +             gpio_cd =3D !gpio_cd;
>
> MMC_CAP2_CD_ACTIVE_HIGH is already handled in
> mmc_gpiod_request_cd(), and this turns an error (gpio_cd < 0)
> into 0, which is not right.

But in case of 'cd-inverted' is not specified, the gpio CD pin return
0 which will be explained as card is not present.
>
> > +
> >       if (gpio_cd >=3D 0)
> >               return !!gpio_cd;
> >
>