[PATCH] ARM: dts: i.MX8MP: increase off-on delay on the SD Vcc regulator

[Sascha Hauer]

On Tue, Nov 01, 2022 at 02:30:50PM +0100, Marco Felsch wrote:
> This commit is required to fix the SD card detection mechanism. Without
> this commit the SD card (auto-)detection fails when booted from this
> sd-card:
> 
>   mmc1: Query interface conditions failed: -110
>   mmc1: SD operation condition set timed out
> 
> The commit is ported from U-Boot:
> 
> | commit 247bbeb74c186963d9365db3136d0285618bd9a7
> | Author: Andrey Zhizhikin <andrey.zhizhikin at leica-geosystems.com>
> | Date:   Sat Dec 5 17:29:17 2020 +0000
> |
> |     ARM: dts: imx8m: increase off-on delay on the SD Vcc regulator
> |
> |     Some SD Card controller and power circuitry has increased capacitance,
> |     which keeps the internal logic remains powered after regulator is switch
> |     off. This is generally the case when card is switched to SD104 mode,
> |     where a power cycle should be performed. In case if the card internal
> |     logic remains powered, it causes a subsequent failure of mode
> |     transition, effectively leading to failed enumeration.
> |
> |     Introduce a delay of 20 msec in order to provide a possibility for
> |     internal card circuitry to drain voltages and perform a power cycle
> |     correctly.
> |
> |     Similar fix is done in commit c49d0ac38a76 ("ARM: dts: rmobile: Increase
> |     off-on delay on the SD Vcc regulator") targeted Renesas SOCs.
> |
> |     Signed-off-by: Andrey Zhizhikin <andrey.zhizhikin at leica-geosystems.com>
> |     Cc: Stefano Babic <sbabic at denx.de>
> 
> Signed-off-by: Marco Felsch <m.felsch at pengutronix.de>
> ---
>  arch/arm/dts/imx8mp-evk.dts | 4 ++++
>  1 file changed, 4 insertions(+)

Applied, thanks

Sascha

> 
> diff --git a/arch/arm/dts/imx8mp-evk.dts b/arch/arm/dts/imx8mp-evk.dts
> index 3264ade4b8..77b438287c 100644
> --- a/arch/arm/dts/imx8mp-evk.dts
> +++ b/arch/arm/dts/imx8mp-evk.dts
> @@ -35,6 +35,10 @@
>  	reset-deassert-us = <100000>;
>  };
>  
> +&reg_usdhc2_vmmc {
> +	off-on-delay-us = <20000>;
> +};
> +
>  &usdhc2 {
>  	#address-cells = <1>;
>  	#size-cells = <1>;
> -- 
> 2.30.2
> 
> 
> 

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