From: Lucas Tanure <tanure@linux.com>
To: Neil Armstrong <neil.armstrong@linaro.org>,
	Kevin Hilman <khilman@baylibre.com>,
	Jerome Brunet <jbrunet@baylibre.com>,
	Martin Blumenstingl <martin.blumenstingl@googlemail.com>,
	Rob Herring <robh@kernel.org>,
	Krzysztof Kozlowski <krzk+dt@kernel.org>,
	Conor Dooley <conor+dt@kernel.org>,
	Stephen Boyd <sboyd@kernel.org>
Cc: Jian Hu <jian.hu@amlogic.com>,
	Ronald Claveau <linux-kernel-dev@aliel.fr>,
	Brian Masney <bmasney@redhat.com>,
	Chuan Liu <chuan.liu@amlogic.com>,
	linux-arm-kernel@lists.infradead.org,
	linux-amlogic@lists.infradead.org,
	devicetree@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	linux-clk@vger.kernel.org
Subject: [PATCH 3/4] arm64: dts: amlogic: t7: khadas-vim4: add the PWM-driven supplies
Date: Sat, 29 Aug 2026 10:47:57 +0100
Message-ID: <20260829094758.23248-4-tanure@linux.com>
In-Reply-To: <20260829094758.23248-1-tanure@linux.com>
References: <20260829094758.23248-1-tanure@linux.com>
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MIME-Version: 1.0
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The board powers its two CPU clusters, the GPU, the NPU, the memory and
the always-on domain from regulators steered by PWM outputs. None of
them were described, so Linux treated those outputs as unused and
switched them off part way through boot. The supplies then drifted away
from the levels the bootloader had set, which showed up as random hangs
and memory corruption.

Describe each supply so it has an owner and is left alone.

The voltage ranges are read off the feedback networks on the board
schematic. VDDNPU is deliberately not the range in Amlogic's own
device tree: this board fits a different feedback resistor, which
puts it about 40mV higher at both ends.

Fixes: 8c45bf9ae4ef ("arm64: dts: amlogic: t7: khadas-vim4: Add power regulators")
Assisted-by: Claude:claude-opus-5
Signed-off-by: Lucas Tanure <tanure@linux.com>
---
 .../amlogic/amlogic-t7-a311d2-khadas-vim4.dts | 110 +++++++++++++++++-
 1 file changed, 109 insertions(+), 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 c94afaaf8826..77abfd555ec5 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
@@ -104,6 +104,66 @@ vcc5v0_usb: regulator-vcc-usb {
 		enable-active-high;
 	};
 
+	vdd_ddr: regulator-vddddr {
+		/*
+		 * SY8003ADFC Regulator.
+		 */
+		compatible = "pwm-regulator";
+		regulator-name = "VDDDDR";
+		regulator-min-microvolt = <690000>;
+		regulator-max-microvolt = <890000>;
+		pwm-supply = <&dc_in>;
+		pwms = <&pwm_ao_gh 0 1500 0>;
+		pwm-dutycycle-range = <100 0>;
+		regulator-boot-on;
+		regulator-always-on;
+	};
+
+	vdd_ee: regulator-vddee {
+		/*
+		 * MP8756GD Regulator.
+		 */
+		compatible = "pwm-regulator";
+		regulator-name = "VDDEE";
+		regulator-min-microvolt = <700000>;
+		regulator-max-microvolt = <922000>;
+		pwm-supply = <&dc_in>;
+		pwms = <&pwm_ao_ab 0 1500 0>;
+		pwm-dutycycle-range = <100 0>;
+		regulator-boot-on;
+		regulator-always-on;
+	};
+
+	vdd_gpu: regulator-vddgpu {
+		/*
+		 * SY8003ADFC Regulator.
+		 */
+		compatible = "pwm-regulator";
+		regulator-name = "VDDGPU";
+		regulator-min-microvolt = <700000>;
+		regulator-max-microvolt = <922000>;
+		pwm-supply = <&dc_in>;
+		pwms = <&pwm_ao_ef 0 1500 0>;
+		pwm-dutycycle-range = <100 0>;
+		regulator-boot-on;
+		regulator-always-on;
+	};
+
+	vdd_npu: regulator-vddnpu {
+		/*
+		 * SY8003ADFC Regulator.
+		 */
+		compatible = "pwm-regulator";
+		regulator-name = "VDDNPU";
+		regulator-min-microvolt = <733000>;
+		regulator-max-microvolt = <933000>;
+		pwm-supply = <&dc_in>;
+		pwms = <&pwm_ao_ef 1 1500 0>;
+		pwm-dutycycle-range = <100 0>;
+		regulator-boot-on;
+		regulator-always-on;
+	};
+
 	vddao_1v8: regulator-vddao-1v8 {
 		compatible = "regulator-fixed";
 		regulator-name = "VDDAO_1V8";
@@ -122,6 +182,36 @@ vddao_3v3: regulator-vddao-3v3 {
 		regulator-always-on;
 	};
 
+	vddcpu_a: regulator-vddcpu-a {
+		/*
+		 * MP8756GD Regulator.
+		 */
+		compatible = "pwm-regulator";
+		regulator-name = "VDDCPU_A";
+		regulator-min-microvolt = <689000>;
+		regulator-max-microvolt = <1049000>;
+		pwm-supply = <&dc_in>;
+		pwms = <&pwm_ao_cd 1 1500 0>;
+		pwm-dutycycle-range = <100 0>;
+		regulator-boot-on;
+		regulator-always-on;
+	};
+
+	vddcpu_b: regulator-vddcpu-b {
+		/*
+		 * MP8756GD Regulator.
+		 */
+		compatible = "pwm-regulator";
+		regulator-name = "VDDCPU_B";
+		regulator-min-microvolt = <689000>;
+		regulator-max-microvolt = <1049000>;
+		pwm-supply = <&dc_in>;
+		pwms = <&pwm_ao_ab 1 1500 0>;
+		pwm-dutycycle-range = <100 0>;
+		regulator-boot-on;
+		regulator-always-on;
+	};
+
 	vddio_1v8: regulator-vddio-1v8 {
 		compatible = "regulator-fixed";
 		regulator-name = "VDDIO_1V8";
@@ -172,9 +262,27 @@ &pwm_ab {
 	pinctrl-names = "default";
 };
 
+&pwm_ao_ab {
+	status = "okay";
+	pinctrl-0 = <&pwm_ao_a_pins>, <&pwm_ao_b_pins>;
+	pinctrl-names = "default";
+};
+
 &pwm_ao_cd {
 	status = "okay";
-	pinctrl-0 = <&pwm_ao_c_d_pins>;
+	pinctrl-0 = <&pwm_ao_c_d_pins>, <&pwm_ao_d_pins>;
+	pinctrl-names = "default";
+};
+
+&pwm_ao_ef {
+	status = "okay";
+	pinctrl-0 = <&pwm_ao_e_pins>, <&pwm_ao_f_pins>;
+	pinctrl-names = "default";
+};
+
+&pwm_ao_gh {
+	status = "okay";
+	pinctrl-0 = <&pwm_ao_g_e_pins>;
 	pinctrl-names = "default";
 };
 
-- 
2.55.0