Re: [PATCH V6 11/12] arm64: dts: imx8m[m,q]-evk: change to use off-on-delay-us in regulator
From: Shawn Guo
Date: Fri Nov 18 2022 - 22:12:14 EST
On Thu, Nov 17, 2022 at 05:54:02PM +0800, Peng Fan (OSS) wrote:
> From: Haibo Chen <haibo.chen@xxxxxxx>
>
> Some SD Card controller and power circuitry has increased capacitance,
> so the usual toggling of regulator to power the card off and on
> is insufficient.
>
> According to SD spec, for sd card power reset operation, the sd card
> supply voltage needs to be lower than 0.5v and keep over 1ms, otherwise,
> next time power back the sd card supply voltage to 3.3v, sd card can't
> support SD3.0 mode again.
>
> This patch add the off-on-delay-us, make sure the sd power reset behavior
> is align with the specification. Without this patch, when do quick system
> suspend/resume test, some sd card can't work at SD3.0 mode after system
> resume back.
>
> Signed-off-by: Haibo Chen <haibo.chen@xxxxxxx>
> Signed-off-by: Peng Fan <peng.fan@xxxxxxx>
> Reviewed-by: Marco Felsch <m.felsch@xxxxxxxxxxxxxx>
Applied, thanks!