RE: [PATCH v2] arm64: dts: rockchip: Fix SD card init on rk3399-nanopi4

From: Christian Loehle <CLoehle@hyperstone.com>
To: "Christian Kohlschütter" <christian@kohlschutter.com>,
	"Robin Murphy" <robin.murphy@arm.com>,
	"Markus Reichl" <m.reichl@fivetechno.de>,
	"Heiko Stübner" <heiko@sntech.de>,
	"linux-arm-kernel@lists.infradead.org"
	<linux-arm-kernel@lists.infradead.org>,
	"linux-rockchip@lists.infradead.org"
	<linux-rockchip@lists.infradead.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"Linux MMC List" <linux-mmc@vger.kernel.org>
Subject: RE: [PATCH v2] arm64: dts: rockchip: Fix SD card init on rk3399-nanopi4
Date: Thu, 14 Jul 2022 16:44:08 +0000	[thread overview]
Message-ID: <eec07acea8694191a75880acc397dafe@hyperstone.com> (raw)
In-Reply-To: <A9634366-A012-43D2-B253-8BB9BF6005C7@kohlschutter.com>

I only briefly skimmed the discussion, but does this mean that a soft-reset (CMD0) of a UHS (post-voltage-switch) will not work?
(As the card/spec requires a power-cycle by the host which will not come, right?)
Can you try this real quick? I can give you a mmc-utils snippet if you have trouble issuing one.
If that does indeed not work I think the general approach is to disable uhs in the dts or at least document that.
Regards,
Christian

-----Original Message-----
From: Christian Kohlschütter <christian@kohlschutter.com> 
Sent: Donnerstag, 14. Juli 2022 18:27
To: Robin Murphy <robin.murphy@arm.com>; Markus Reichl <m.reichl@fivetechno.de>; Heiko Stübner <heiko@sntech.de>; linux-arm-kernel@lists.infradead.org; linux-rockchip@lists.infradead.org; linux-kernel@vger.kernel.org; Linux MMC List <linux-mmc@vger.kernel.org>
Subject: [PATCH v2] arm64: dts: rockchip: Fix SD card init on rk3399-nanopi4

mmc/SD-card initialization may fail on NanoPi r4s with
"mmc1: problem reading SD Status register" /
"mmc1: error -110 whilst initialising SD card"

Moreover, rebooting would also sometimes hang.

This is caused by the gpio entry for the vcc3v0-sd regulator;
even though it appears to be the correct GPIO pin, the presence
of the binding causes these errors.

Fix the regulator to drop the gpio binding and add a comment
to prevent accidental reintroduction of that entry.

Signed-off-by: Christian Kohlschütter <christian@kohlschutter.com>
---
 arch/arm64/boot/dts/rockchip/rk3399-nanopi4.dtsi | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/boot/dts/rockchip/rk3399-nanopi4.dtsi b/arch/arm64/boot/dts/rockchip/rk3399-nanopi4.dtsi
index 8c0ff6c96e03..d5f8a62e01be 100644
--- a/arch/arm64/boot/dts/rockchip/rk3399-nanopi4.dtsi
+++ b/arch/arm64/boot/dts/rockchip/rk3399-nanopi4.dtsi
@@ -67,7 +67,7 @@ vcc1v8_s3: vcc1v8-s3 {
 	vcc3v0_sd: vcc3v0-sd {
 		compatible = "regulator-fixed";
 		enable-active-high;
-		gpio = <&gpio0 RK_PA1 GPIO_ACTIVE_HIGH>;
+		// gpio = <&gpio0 RK_PA1 GPIO_ACTIVE_HIGH>; // breaks SDHC card support
 		pinctrl-names = "default";
 		pinctrl-0 = <&sdmmc0_pwr_h>;
 		regulator-always-on;
-- 
2.36.1



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