linux-kernel - Re: [PATCH] sdhci: Fix SD card detection issue

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Date: Mon, 15 Apr 2024 09:23:11 +0100
From: "Russell King (Oracle)" <linux@...linux.org.uk>
To: richard clark <richard.xnu.clark@...il.com>
Cc: Adrian Hunter <adrian.hunter@...el.com>, ulf.hansson@...aro.org,
	linux-mmc@...r.kernel.org, linux-kernel@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH] sdhci: Fix SD card detection issue

On Mon, Apr 15, 2024 at 04:17:14PM +0800, richard clark wrote:
> On Mon, Apr 15, 2024 at 3:22 PM Russell King (Oracle)
> <linux@...linux.org.uk> wrote:
> >
> > On Mon, Apr 15, 2024 at 10:18:39AM +0300, Adrian Hunter wrote:
> > > On 15/04/24 10:06, Richard Clark wrote:
> > > > The mmc_gpio_get_cd(...) will return 0 called from sdhci_get_cd(...), which 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 correct, more
> > >
> > > SDHCI spec covers the SDHCI lines.  GPIO is separate.
> >
> > ... and the key bit of information that should be mentioned is in the
> > case of a GPIO, the GPIO library can be told if a GPIO is active-high
> > or active-low in either firmware or via the GPIO lookup data, and this
> > should be used instead of drivers inventing their own "quirking".
> >
> Agree! But unfortunately, it seems I can't find the right place to
> handle this from either firmware or via the GPIO lookup data. Will be
> appreciated if any suggestion about that?!

If you're using DT, then, for example:

        cd-gpios = <&gpio1 4 GPIO_ACTIVE_LOW>;

is all it takes. If you are using firmware then GPIO lookup data isn't
what you should be using. I'm afraid I don't know the ACPI bindings for
SDHCI.

-- 
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