linux-kernel - [PATCH 2/2] arm64: dts: rockchip: override BIOS_DISABLE signal via GPIO hog on RK3399 Puma

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Message-Id: <20240731-puma-emmc-6-v1-2-4e28eadf32d0@cherry.de>
Date: Wed, 31 Jul 2024 13:05:29 +0200
From: Quentin Schulz <foss+kernel@...il.net>
To: Rob Herring <robh@...nel.org>, Krzysztof Kozlowski <krzk+dt@...nel.org>, 
 Conor Dooley <conor+dt@...nel.org>, Heiko Stuebner <heiko@...ech.de>, 
 Judy Hsiao <judyhsiao@...omium.org>, 
 Brian Norris <briannorris@...omium.org>
Cc: stable@...r.kernel.org, devicetree@...r.kernel.org, 
 linux-arm-kernel@...ts.infradead.org, linux-rockchip@...ts.infradead.org, 
 linux-kernel@...r.kernel.org, Quentin Schulz <quentin.schulz@...rry.de>, 
 foss+kernel@...il.net
Subject: [PATCH 2/2] arm64: dts: rockchip: override BIOS_DISABLE signal via
 GPIO hog on RK3399 Puma

From: Quentin Schulz <quentin.schulz@...rry.de>

The Qseven BIOS_DISABLE signal on the RK3399-Q7 keeps the on-module eMMC
and SPI flash powered-down initially (in fact it keeps the reset signal
asserted). BIOS_DISABLE_OVERRIDE pin allows to override that signal so
that eMMC and SPI can be used regardless of the state of the signal.

Let's make this GPIO a hog so that it's reserved and locked in the
proper state.

At the same time, make sure the pin is reserved for the hog and cannot
be requested by another node.

Cc: stable@...r.kernel.org
Signed-off-by: Quentin Schulz <quentin.schulz@...rry.de>
---
 arch/arm64/boot/dts/rockchip/rk3399-puma.dtsi | 23 ++++++++++++++++++++++-
 1 file changed, 22 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/boot/dts/rockchip/rk3399-puma.dtsi b/arch/arm64/boot/dts/rockchip/rk3399-puma.dtsi
index a782e614d9bba..d24444cdf54af 100644
--- a/arch/arm64/boot/dts/rockchip/rk3399-puma.dtsi
+++ b/arch/arm64/boot/dts/rockchip/rk3399-puma.dtsi
@@ -154,6 +154,22 @@ bios-disable-hog {
 	};
 };
 
+&gpio3 {
+	/*
+	 * The Qseven BIOS_DISABLE signal on the RK3399-Q7 keeps the on-module
+	 * eMMC and SPI flash powered-down initially (in fact it keeps the
+	 * reset signal asserted). BIOS_DISABLE_OVERRIDE pin allows to override
+	 * that signal so that eMMC and SPI can be used regardless of the state
+	 * of the signal.
+	 */
+	bios-disable-override-hog {
+		gpios = <RK_PD5 GPIO_ACTIVE_LOW>;
+		gpio-hog;
+		line-name = "bios_disable_override";
+		output-high;
+	};
+};
+
 &gmac {
 	assigned-clocks = <&cru SCLK_RMII_SRC>;
 	assigned-clock-parents = <&clkin_gmac>;
@@ -458,9 +474,14 @@ &pcie_clkreqn_cpm {
 
 &pinctrl {
 	pinctrl-names = "default";
-	pinctrl-0 = <&q7_thermal_pin>;
+	pinctrl-0 = <&q7_thermal_pin &bios_disable_override_hog_pin>;
 
 	gpios {
+		bios_disable_override_hog_pin: bios-disable-override-hog-pin {
+			rockchip,pins =
+				<3 RK_PD5 RK_FUNC_GPIO &pcfg_pull_down>;
+		};
+
 		q7_thermal_pin: q7-thermal-pin {
 			rockchip,pins =
 				<0 RK_PA3 RK_FUNC_GPIO &pcfg_pull_up>;

-- 
2.45.2