[PATCH v2] arm64: dts: qcom: hamoa-iot-evk: Add backlight support for eDP panel

[Yongxing Mou <yongxing.mou@oss.qualcomm.com>]

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@oss.qualcomm.com>
---
Changes in v2:
- Add hamoa-iot-evk to the commit subject. [Konrad]
- Correct the property order in the vreg_edp_bl node. [Konrad]
- Link to v1: https://lore.kernel.org/r/20251028-hamoa_dvt_backlight-v1-1-97ecb8d0ad01@oss.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 36dd6599402b..454aad40de34 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-0 = <&edp_bl_reg_en>;
+		pinctrl-names = "default";
+
+		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@oss.qualcomm.com>