[PATCH v2] arm64: dts: allwinner: Revert SD card CD GPIO for Pine64-LTS

[Andre Przywara]

On Wed, 14 Apr 2021 20:35:03 +0200
Michael Weiser <michael.weiser at gmx.de> wrote:

Maxime, Chen-Yu:

can you please try to push this patch into 5.12, still?
The Pine64-LTS' SD card is broken otherwise, on both versions of the
board. The incriminating patch was introduced in 5.12-rc1 (my bad!), so
it qualifies as a regression fix.

Many thanks!
Andre

> On Wed, Apr 14, 2021 at 11:47:40AM +0100, Andre Przywara wrote:
> 
> > Commit 941432d00768 ("arm64: dts: allwinner: Drop non-removable from
> > SoPine/LTS SD card") enabled the card detect GPIO for the SOPine module,
> > along the way with the Pine64-LTS, which share the same base .dtsi.  
> 
> > This was based on the observation that the Pine64-LTS has as "push-push"
> > SD card socket, and that the schematic mentions the card detect GPIO.  
> 
> > After having received two reports about failing SD card access with that
> > patch, some more research and polls on that subject revealed that there
> > are at least two different versions of the Pine64-LTS out there:
> > - On some boards (including mine) the card detect pin is "stuck" at
> >   high, regardless of an microSD card being inserted or not.
> > - On other boards the card-detect is working, but is active-high, by
> >   virtue of an explicit inverter circuit, as shown in the schematic.  
> 
> > To cover all versions of the board out there, and don't take any chances,
> > let's revert the introduction of the active-low CD GPIO, but let's use
> > the broken-cd property for the Pine64-LTS this time. That should avoid
> > regressions and should work for everyone, even allowing SD card changes
> > now.
> > The SOPine card detect has proven to be working, so let's keep that
> > GPIO in place.  
> 
> I can confirm that this change works on my Pine64 LTS boards (with
> working high-active card detect) when applied to today's linux-next (which
> already includes your previous change to change the card detect GPIO
> from low- to high-active in sun50i-a64-sopine.dtsi).
> 
> > Fixes: 941432d00768 ("arm64: dts: allwinner: Drop non-removable from SoPine/LTS SD card")
> > Reported-by: Michael Weiser <michael.weiser at gmx.de>
> > Reported-by: Daniel Kulesz <kuleszdl at posteo.org>
> > Suggested-by: Chen-Yu Tsai <wens at csie.org>
> > Signed-off-by: Andre Przywara <andre.przywara at arm.com>  
> 
> Tested-by: Michael Weiser <michael.weiser at gmx.de>
> 
> Thanks!
> Michael
> 
> > ---
> >  arch/arm64/boot/dts/allwinner/sun50i-a64-pine64-lts.dts | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)  
> 
> > diff --git a/arch/arm64/boot/dts/allwinner/sun50i-a64-pine64-lts.dts b/arch/arm64/boot/dts/allwinner/sun50i-a64-pine64-lts.dts
> > index e79ce49e7e6a..596a25907432 100644
> > --- a/arch/arm64/boot/dts/allwinner/sun50i-a64-pine64-lts.dts
> > +++ b/arch/arm64/boot/dts/allwinner/sun50i-a64-pine64-lts.dts
> > @@ -21,5 +21,5 @@
> >  };  
> 
> >  &mmc0 {
> > -	cd-gpios = <&pio 5 6 GPIO_ACTIVE_LOW>; /* PF6 push-push switch */
> > +	broken-cd;		/* card detect is broken on *some* boards */
> >  };  
>