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From: Lucas Tanure <tanure@linux.com>
To: Neil Armstrong <neil.armstrong@linaro.org>,
	Kevin Hilman <khilman@baylibre.com>,
	Rob Herring <robh@kernel.org>,
	Krzysztof Kozlowski <krzk+dt@kernel.org>,
	Conor Dooley <conor+dt@kernel.org>
Cc: linux-arm-kernel@lists.infradead.org,
	Xianwei Zhao <xianwei.zhao@amlogic.com>,
	linux-amlogic@lists.infradead.org, devicetree@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH 2/2] arm64: dts: amlogic: t7: khadas-vim4: allow the SD card to be power cycled
Date: Tue, 18 Aug 2026 20:11:59 +0100	[thread overview]
Message-ID: <20260818191159.11523-3-tanure@linux.com> (raw)
In-Reply-To: <20260818191159.11523-1-tanure@linux.com>

SD cards start at 3.3V and switch to 1.8V to reach UHS-I speeds. Some
cards refuse that switch, and the SD specification says the only way
to recover is to power the card off and start again.

SD_3V3 is marked regulator-always-on, so the supply never goes off,
the card stays stuck half way through the switch, and the MMC core
retries forever:

  mmc1: error -95 whilst initialising SD card

Drop regulator-always-on. regulator-boot-on still turns the supply on
at boot, and a card that refuses the switch now falls back to high
speed instead of failing to initialise.

Fixes: 8c45bf9ae4ef ("arm64: dts: amlogic: t7: khadas-vim4: Add power regulators")
Signed-off-by: Lucas Tanure <tanure@linux.com>
Assisted-by: Claude:claude-fable-5
---
 arch/arm64/boot/dts/amlogic/amlogic-t7-a311d2-khadas-vim4.dts | 1 -
 1 file changed, 1 deletion(-)

diff --git a/arch/arm64/boot/dts/amlogic/amlogic-t7-a311d2-khadas-vim4.dts b/arch/arm64/boot/dts/amlogic/amlogic-t7-a311d2-khadas-vim4.dts
index 677069e58f30..3f53630e107f 100644
--- a/arch/arm64/boot/dts/amlogic/amlogic-t7-a311d2-khadas-vim4.dts
+++ b/arch/arm64/boot/dts/amlogic/amlogic-t7-a311d2-khadas-vim4.dts
@@ -71,7 +71,6 @@ sd_3v3: regulator-sdcard-3v3 {
 		vin-supply = <&vddao_3v3>;
 		gpio = <&gpio GPIOD_11 GPIO_ACTIVE_LOW>;
 		regulator-boot-on;
-		regulator-always-on;
 	};
 
 	sdio_pwrseq: sdio-pwrseq {
-- 
2.55.0


WARNING: multiple messages have this Message-ID (diff)
From: Lucas Tanure <tanure@linux.com>
To: Neil Armstrong <neil.armstrong@linaro.org>,
	Kevin Hilman <khilman@baylibre.com>,
	Rob Herring <robh@kernel.org>,
	Krzysztof Kozlowski <krzk+dt@kernel.org>,
	Conor Dooley <conor+dt@kernel.org>
Cc: linux-arm-kernel@lists.infradead.org,
	Xianwei Zhao <xianwei.zhao@amlogic.com>,
	linux-amlogic@lists.infradead.org, devicetree@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH 2/2] arm64: dts: amlogic: t7: khadas-vim4: allow the SD card to be power cycled
Date: Tue, 18 Aug 2026 20:11:59 +0100	[thread overview]
Message-ID: <20260818191159.11523-3-tanure@linux.com> (raw)
In-Reply-To: <20260818191159.11523-1-tanure@linux.com>

SD cards start at 3.3V and switch to 1.8V to reach UHS-I speeds. Some
cards refuse that switch, and the SD specification says the only way
to recover is to power the card off and start again.

SD_3V3 is marked regulator-always-on, so the supply never goes off,
the card stays stuck half way through the switch, and the MMC core
retries forever:

  mmc1: error -95 whilst initialising SD card

Drop regulator-always-on. regulator-boot-on still turns the supply on
at boot, and a card that refuses the switch now falls back to high
speed instead of failing to initialise.

Fixes: 8c45bf9ae4ef ("arm64: dts: amlogic: t7: khadas-vim4: Add power regulators")
Signed-off-by: Lucas Tanure <tanure@linux.com>
Assisted-by: Claude:claude-fable-5
---
 arch/arm64/boot/dts/amlogic/amlogic-t7-a311d2-khadas-vim4.dts | 1 -
 1 file changed, 1 deletion(-)

diff --git a/arch/arm64/boot/dts/amlogic/amlogic-t7-a311d2-khadas-vim4.dts b/arch/arm64/boot/dts/amlogic/amlogic-t7-a311d2-khadas-vim4.dts
index 677069e58f30..3f53630e107f 100644
--- a/arch/arm64/boot/dts/amlogic/amlogic-t7-a311d2-khadas-vim4.dts
+++ b/arch/arm64/boot/dts/amlogic/amlogic-t7-a311d2-khadas-vim4.dts
@@ -71,7 +71,6 @@ sd_3v3: regulator-sdcard-3v3 {
 		vin-supply = <&vddao_3v3>;
 		gpio = <&gpio GPIOD_11 GPIO_ACTIVE_LOW>;
 		regulator-boot-on;
-		regulator-always-on;
 	};
 
 	sdio_pwrseq: sdio-pwrseq {
-- 
2.55.0


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  parent reply	other threads:[~2026-08-18 19:12 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-08-18 19:11 [PATCH 0/2] arm64: dts: amlogic: t7: fix UART clock and SD card recovery Lucas Tanure
2026-08-18 19:11 ` Lucas Tanure
2026-08-18 19:11 ` [PATCH 1/2] arm64: dts: amlogic: t7: use the real UART pclk Lucas Tanure
2026-08-18 19:11   ` Lucas Tanure
2026-08-18 19:11 ` Lucas Tanure [this message]
2026-08-18 19:11   ` [PATCH 2/2] arm64: dts: amlogic: t7: khadas-vim4: allow the SD card to be power cycled Lucas Tanure

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