linux-kernel - Re: [PATCH 14/15] arm64: dts: imx8m[m, p]-evk: change to use off-on-delay-us in regulator

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Message-ID: <20221020141354.jxyycnt3nzm7frcr@pengutronix.de>
Date:   Thu, 20 Oct 2022 16:13:54 +0200
From:   Marco Felsch <m.felsch@...gutronix.de>
To:     "Peng Fan (OSS)" <peng.fan@....nxp.com>
Cc:     robh+dt@...nel.org, krzysztof.kozlowski+dt@...aro.org,
        shawnguo@...nel.org, s.hauer@...gutronix.de,
        devicetree@...r.kernel.org, Peng Fan <peng.fan@....com>,
        linux-kernel@...r.kernel.org, Haibo Chen <haibo.chen@....com>,
        linux-imx@....com, kernel@...gutronix.de, festevam@...il.com,
        linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH 14/15] arm64: dts: imx8m[m, p]-evk: change to use
 off-on-delay-us in regulator

On 22-10-20, Peng Fan (OSS) wrote:
> From: Haibo Chen <haibo.chen@....com>
> 
> After commit f7907e57aea2 ("regulator: fixed: add off-on-delay"), user
> can use "off-on-delay-us" to define the regulator off-delay time.
> 
> For SD card, according to the spec requirement, for sd card power reset
> operation, it need sd card supply voltage 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 to each board, 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.

Please mention that the real issue which is a capicity which gets
unloaded to slow. Please see the u-boot commit for this which explains
it better IMHO.

Regards,
  Marco


> 
> Signed-off-by: Haibo Chen <haibo.chen@....com>
> Signed-off-by: Peng Fan <peng.fan@....com>
> ---
>  arch/arm64/boot/dts/freescale/imx8mm-evk.dts  | 2 +-
>  arch/arm64/boot/dts/freescale/imx8mm-evk.dtsi | 1 +
>  arch/arm64/boot/dts/freescale/imx8mq-evk.dts  | 1 +
>  3 files changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/arm64/boot/dts/freescale/imx8mm-evk.dts b/arch/arm64/boot/dts/freescale/imx8mm-evk.dts
> index c93387fcd498..898735965ac9 100644
> --- a/arch/arm64/boot/dts/freescale/imx8mm-evk.dts
> +++ b/arch/arm64/boot/dts/freescale/imx8mm-evk.dts
> @@ -22,7 +22,7 @@ reg_sd1_vmmc: sd1_regulator {
>  		regulator-min-microvolt = <3300000>;
>  		regulator-max-microvolt = <3300000>;
>  		gpio = <&gpio2 10 GPIO_ACTIVE_HIGH>;
> -		off-on-delay = <20000>;
> +		off-on-delay-us = <20000>;
>  		startup-delay-us = <100>;
>  		enable-active-high;
>  	};
> diff --git a/arch/arm64/boot/dts/freescale/imx8mm-evk.dtsi b/arch/arm64/boot/dts/freescale/imx8mm-evk.dtsi
> index ce450965e837..fdbcd2483efc 100644
> --- a/arch/arm64/boot/dts/freescale/imx8mm-evk.dtsi
> +++ b/arch/arm64/boot/dts/freescale/imx8mm-evk.dtsi
> @@ -56,6 +56,7 @@ reg_usdhc2_vmmc: regulator-usdhc2 {
>  		regulator-min-microvolt = <3300000>;
>  		regulator-max-microvolt = <3300000>;
>  		gpio = <&gpio2 19 GPIO_ACTIVE_HIGH>;
> +		off-on-delay-us = <20000>;
>  		enable-active-high;
>  	};
>  
> diff --git a/arch/arm64/boot/dts/freescale/imx8mq-evk.dts b/arch/arm64/boot/dts/freescale/imx8mq-evk.dts
> index 82387b9cb800..07d9fb2aacf8 100644
> --- a/arch/arm64/boot/dts/freescale/imx8mq-evk.dts
> +++ b/arch/arm64/boot/dts/freescale/imx8mq-evk.dts
> @@ -46,6 +46,7 @@ reg_usdhc2_vmmc: regulator-vsd-3v3 {
>  		regulator-min-microvolt = <3300000>;
>  		regulator-max-microvolt = <3300000>;
>  		gpio = <&gpio2 19 GPIO_ACTIVE_HIGH>;
> +		off-on-delay-us = <20000>;
>  		enable-active-high;
>  	};
>  
> -- 
> 2.37.1
> 
> 
>