linux-kernel - [PATCH V3 13/14] arm64: dts: imx8m[m,q]-evk: change to use off-on-delay-us in regulator

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Message-Id: <20221108021820.1854971-14-peng.fan@oss.nxp.com>
Date:   Tue,  8 Nov 2022 10:18:19 +0800
From:   "Peng Fan (OSS)" <peng.fan@....nxp.com>
To:     robh+dt@...nel.org, krzysztof.kozlowski+dt@...aro.org,
        shawnguo@...nel.org, s.hauer@...gutronix.de
Cc:     kernel@...gutronix.de, festevam@...il.com, linux-imx@....com,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org,
        Haibo Chen <haibo.chen@....com>, Peng Fan <peng.fan@....com>
Subject: [PATCH V3 13/14] arm64: dts: imx8m[m,q]-evk: change to use off-on-delay-us in regulator

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>
---
 arch/arm64/boot/dts/freescale/imx8mm-evk.dtsi | 1 +
 arch/arm64/boot/dts/freescale/imx8mq-evk.dts  | 1 +
 2 files changed, 2 insertions(+)

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