[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <20221119030830.GI16229@T480>
Date: Sat, 19 Nov 2022 11:08:31 +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, Peng Fan <peng.fan@....com>,
Marco Felsch <m.felsch@...gutronix.de>
Subject: Re: [PATCH V6 08/12] arm64: dts: imx8mn-evk: set off-on-delay-us in
regulator
On Thu, Nov 17, 2022 at 05:53:59PM +0800, Peng Fan (OSS) wrote:
> From: Peng Fan <peng.fan@....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: Peng Fan <peng.fan@....com>
> Reviewed-by: Marco Felsch <m.felsch@...gutronix.de>
Applied, thanks!
Powered by blists - more mailing lists