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

[Adrian Hunter]

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;


> 
> 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
>>
>