Re: [PATCH 2/2] ARM: dts: at91: sama5d27_som1_ek: add mmc capabilities for SDMMC0

[Ludovic Desroches]

On Thu, Aug 08, 2019 at 03:57:30PM +0300, Adrian Hunter wrote:
> On 8/08/19 3:42 PM, Ludovic Desroches wrote:
> > On Thu, Aug 08, 2019 at 10:35:43AM +0200, Eugen Hristev - M18282 wrote:
> >> From: Eugen Hristev <eugen.hristev@xxxxxxxxxxxxx>
> >>
> >> Add mmc capabilities for SDMMC0 for this board.
> >> With this enabled, eMMC connected card is detected as:
> >>
> >> mmc0: new DDR MMC card at address 0001
> >>
> >> Signed-off-by: Eugen Hristev <eugen.hristev@xxxxxxxxxxxxx>
> > Acked-by: Ludovic Desroches <ludovic.desroches@xxxxxxxxxxxxx>
> > 
> > I am interested to have the some insights about the use of sd-uhs-*
> > properties.
> > 
> > Our IP can't deal with 1V8 by itself. It has a 1V8SEL signal which can
> > be used as the logic control input of a mux. So even if the IP claims
> > to support UHS modes, it depends on the board.
> > 
> > Are the sd-uhs-* properties a way to deal with this? I tend to think no
> > as sdhci_setup_host() will set the caps depending on the content of the
> > capabilities register. Do we have to use the SDHCI_QUIRK_MISSING_CAPS
> > quirk or sdhci-caps/sdhci-caps-mask?
> 
> There is "no-1-8-v" which it looks like sdhci-of-at91.c already supports:
> 
>   sdhci_at91_probe() -> sdhci_get_of_property() -> sdhci_get_property()
> 
>     	if (device_property_present(dev, "no-1-8-v"))
> 		host->quirks2 |= SDHCI_QUIRK2_NO_1_8_V;
> 

Right, I forgot this property. Thanks.

Eugen, do you see cases we can't cover with this property?

Regards

Ludovic

> 
> > 
> > Regards
> > 
> > Ludovic
> > 
> >> ---
> >>  arch/arm/boot/dts/at91-sama5d27_som1_ek.dts | 1 +
> >>  1 file changed, 1 insertion(+)
> >>
> >> diff --git a/arch/arm/boot/dts/at91-sama5d27_som1_ek.dts b/arch/arm/boot/dts/at91-sama5d27_som1_ek.dts
> >> index 149e539..194b3a3 100644
> >> --- a/arch/arm/boot/dts/at91-sama5d27_som1_ek.dts
> >> +++ b/arch/arm/boot/dts/at91-sama5d27_som1_ek.dts
> >> @@ -54,6 +54,7 @@
> >>  
> >>  		sdmmc0: sdio-host@a0000000 {
> >>  			bus-width = <8>;
> >> +			mmc-ddr-3_3v;
> >>  			pinctrl-names = "default";
> >>  			pinctrl-0 = <&pinctrl_sdmmc0_default>;
> >>  			status = "okay";
> >> -- 
> >> 2.7.4
> >>
> > 
>