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Message-ID: <20221119031157.GL16229@T480>
Date: Sat, 19 Nov 2022 11:11:58 +0800
From: Shawn Guo <shawnguo@...nel.org>
To: "Peng Fan (OSS)" <peng.fan@....nxp.com>
Cc: s.hauer@...gutronix.de, kernel@...gutronix.de, festevam@...il.com,
linux-imx@....com, linux-kernel@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org,
Haibo Chen <haibo.chen@....com>, Peng Fan <peng.fan@....com>,
Marco Felsch <m.felsch@...gutronix.de>
Subject: Re: [PATCH V6 11/12] arm64: dts: imx8m[m,q]-evk: change to use
off-on-delay-us in regulator
On Thu, Nov 17, 2022 at 05:54:02PM +0800, Peng Fan (OSS) wrote:
> From: Haibo Chen <haibo.chen@....com>
>
> 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@....com>
> Signed-off-by: Peng Fan <peng.fan@....com>
> Reviewed-by: Marco Felsch <m.felsch@...gutronix.de>
Applied, thanks!
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