Re: [PATCH v2 2/2] arm64: dts: amlogic: t7: khadas-vim4: allow the SD card to be power cycled

[Neil Armstrong <neil.armstrong@linaro.org>]

On 8/23/26 13:53, Lucas Tanure wrote:
> SD cards start at 3.3V and switch to 1.8V to reach UHS-I speeds. Some
> cards refuse that switch, and the SD specification says the only way
> to recover is to power the card off and start again.
> 
> SD_3V3 is marked regulator-always-on, so the supply never goes off,
> the card stays stuck half way through the switch, and the MMC core
> retries forever:
> 
>    mmc1: error -95 whilst initialising SD card
> 
> Drop regulator-always-on. regulator-boot-on still turns the supply on
> at boot, and a card that refuses the switch now falls back to high
> speed instead of failing to initialise.
> 
> Fixes: 8c45bf9ae4ef ("arm64: dts: amlogic: t7: khadas-vim4: Add power regulators")
> Signed-off-by: Lucas Tanure <tanure@linux.com>
> Assisted-by: Claude:claude-fable-5
> ---
>   arch/arm64/boot/dts/amlogic/amlogic-t7-a311d2-khadas-vim4.dts | 1 -
>   1 file changed, 1 deletion(-)
> 
> diff --git a/arch/arm64/boot/dts/amlogic/amlogic-t7-a311d2-khadas-vim4.dts b/arch/arm64/boot/dts/amlogic/amlogic-t7-a311d2-khadas-vim4.dts
> index 75d81ad6830d..c94afaaf8826 100644
> --- a/arch/arm64/boot/dts/amlogic/amlogic-t7-a311d2-khadas-vim4.dts
> +++ b/arch/arm64/boot/dts/amlogic/amlogic-t7-a311d2-khadas-vim4.dts
> @@ -71,7 +71,6 @@ sd_3v3: regulator-sdcard-3v3 {
>   		vin-supply = <&vddao_3v3>;
>   		gpio = <&gpio GPIOD_11 GPIO_ACTIVE_LOW>;
>   		regulator-boot-on;
> -		regulator-always-on;
>   	};
>   
>   	sdio_pwrseq: sdio-pwrseq {

Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>

Thanks,
Neil