linux-kernel - [PATCH] arm64: dts: qcom: Add backlight support for eDP panel

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Message-Id: <20251028-hamoa_dvt_backlight-v1-1-97ecb8d0ad01@oss.qualcomm.com>
Date: Tue, 28 Oct 2025 15:04:26 +0800
From: Yongxing Mou <yongxing.mou@....qualcomm.com>
To: Bjorn Andersson <andersson@...nel.org>,
        Konrad Dybcio <konradybcio@...nel.org>, Rob Herring <robh@...nel.org>,
        Krzysztof Kozlowski <krzk+dt@...nel.org>,
        Conor Dooley <conor+dt@...nel.org>
Cc: linux-arm-msm@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Yongxing Mou <yongxing.mou@....qualcomm.com>
Subject: [PATCH] arm64: dts: qcom: Add backlight support for eDP panel

Previously, the eDP panel backlight was enabled via UEFI. Added backlight
control node in kernel DTS due to some meta may not enable the backlight.

Aligned with other x1e80100-based platforms: the PWM signal is controlled
by PMK8550, and the backlight enable signal is handled by PMC8380.

Signed-off-by: Yongxing Mou <yongxing.mou@....qualcomm.com>
---
 arch/arm64/boot/dts/qcom/hamoa-iot-evk.dts | 55 ++++++++++++++++++++++++++++++
 1 file changed, 55 insertions(+)

diff --git a/arch/arm64/boot/dts/qcom/hamoa-iot-evk.dts b/arch/arm64/boot/dts/qcom/hamoa-iot-evk.dts
index 36dd6599402b4650b7f8ad2c0cd22212116a25fe..fda1b3a3c7673be74832c27849231cba4bc1f25f 100644
--- a/arch/arm64/boot/dts/qcom/hamoa-iot-evk.dts
+++ b/arch/arm64/boot/dts/qcom/hamoa-iot-evk.dts
@@ -17,6 +17,16 @@ aliases {
 		serial1 = &uart14;
 	};
 
+	backlight: backlight {
+		compatible = "pwm-backlight";
+		pwms = <&pmk8550_pwm 0 5000000>;
+		enable-gpios = <&pmc8380_3_gpios 4 GPIO_ACTIVE_HIGH>;
+		power-supply = <&vreg_edp_bl>;
+
+		pinctrl-0 = <&edp_bl_en>, <&edp_bl_pwm>;
+		pinctrl-names = "default";
+	};
+
 	wcd938x: audio-codec {
 		compatible = "qcom,wcd9385-codec";
 
@@ -183,6 +193,22 @@ vreg_edp_3p3: regulator-edp-3p3 {
 		regulator-boot-on;
 	};
 
+	vreg_edp_bl: regulator-edp-bl {
+		compatible = "regulator-fixed";
+
+		regulator-name = "VBL9";
+		regulator-min-microvolt = <3600000>;
+		regulator-max-microvolt = <3600000>;
+
+		gpio = <&pmc8380_3_gpios 10 GPIO_ACTIVE_HIGH>;
+		enable-active-high;
+
+		pinctrl-names = "default";
+		pinctrl-0 = <&edp_bl_reg_en>;
+
+		regulator-boot-on;
+	};
+
 	vreg_nvme: regulator-nvme {
 		compatible = "regulator-fixed";
 
@@ -819,6 +845,8 @@ &mdss_dp3 {
 	aux-bus {
 		panel {
 			compatible = "edp-panel";
+
+			backlight = <&backlight>;
 			power-supply = <&vreg_edp_3p3>;
 
 			port {
@@ -879,6 +907,22 @@ usb0_1p8_reg_en: usb0-1p8-reg-en-state {
 	};
 };
 
+&pmc8380_3_gpios {
+	edp_bl_en: edp-bl-en-state {
+		pins = "gpio4";
+		function = "normal";
+		power-source = <1>;
+		input-disable;
+		output-enable;
+	};
+
+	edp_bl_reg_en: edp-bl-reg-en-state {
+		pins = "gpio10";
+		function = "normal";
+	};
+
+};
+
 &pmc8380_5_gpios {
 	usb0_pwr_1p15_reg_en: usb0-pwr-1p15-reg-en-state {
 		pins = "gpio8";
@@ -890,6 +934,17 @@ usb0_pwr_1p15_reg_en: usb0-pwr-1p15-reg-en-state {
 	};
 };
 
+&pmk8550_gpios {
+	edp_bl_pwm: edp-bl-pwm-state {
+		pins = "gpio5";
+		function = "func3";
+	};
+};
+
+&pmk8550_pwm {
+	status = "okay";
+};
+
 &smb2360_0 {
 	status = "okay";
 };

---
base-commit: f7d2388eeec24966fc4d5cf32d706f0514f29ac5
change-id: 20251028-hamoa_dvt_backlight-373528b7ce7e

Best regards,
-- 
Yongxing Mou <yongxing.mou@....qualcomm.com>