RE: [PATCH 1/8] ARM: dts: microchip: sam9x60_curiosity: Add power-supply properties for sdmmc nodes

[Mihai.Sain]

Hi Krzysztof,

I'm sorry for quoting (email is sent from Outlook).
The sdmmc controller from SAM9 MPUs doesn't support the IO voltage signaling/switching required by the UHS sd-card.
On the electrical schematics of the boards the controller and sd-card power pins are connected to 3V3 regulator.
On the SAMA5 MPUs there is support for IO voltage switching but since we have issues with the tuning procedure required but the UHS cards,
we want to keep vqmmc at 3V3 in order to use high-speed mode.

Best regards,
Mihai Sain

----------------------------------------------------------------------

> diff --git a/arch/arm/boot/dts/microchip/at91-sam9x60_curiosity.dts 
> b/arch/arm/boot/dts/microchip/at91-sam9x60_curiosity.dts
> index c6fbdd29019f..457c54dde0b7 100644
> --- a/arch/arm/boot/dts/microchip/at91-sam9x60_curiosity.dts
> +++ b/arch/arm/boot/dts/microchip/at91-sam9x60_curiosity.dts
> @@ -452,6 +452,8 @@ &sdmmc0 {
>       pinctrl-0 = <&pinctrl_sdmmc0_default &pinctrl_sdmmc0_cd>;
>       cd-gpios = <&pioA 25 GPIO_ACTIVE_LOW>;
>       disable-wp;
> +     vmmc-supply = <&vdd1_3v3>;
> +     vqmmc-supply = <&vdd1_3v3>;

For this and all other patches:

It is surprising that you use the same supply for both. Looks like inaccurate description. It is possible, but I think unlikely because usually VQMMC has lower voltage than 3.3V.

Best regards,
Krzysztof