[PATCH v1 4/4] arm64: dts: mediatek: cherry: Add configuration for display backlight

[AngeloGioacchino Del Regno]

Configure the hardware PWM for the integrated display's backlight:
all Cherry devices enable the backlight with GPIO82 and manage the
PWM via MediaTek disp-pwm on GPIO97.

Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxx>
---
 .../boot/dts/mediatek/mt8195-cherry.dtsi      | 24 +++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/arch/arm64/boot/dts/mediatek/mt8195-cherry.dtsi b/arch/arm64/boot/dts/mediatek/mt8195-cherry.dtsi
index d679a04207d8..c50f1e2914b2 100644
--- a/arch/arm64/boot/dts/mediatek/mt8195-cherry.dtsi
+++ b/arch/arm64/boot/dts/mediatek/mt8195-cherry.dtsi
@@ -22,6 +22,16 @@ aliases {
 		serial0 = &uart0;
 	};
 
+	backlight_lcd0: backlight-lcd0 {
+		compatible = "pwm-backlight";
+		brightness-levels = <0 1023>;
+		default-brightness-level = <576>;
+		enable-gpios = <&pio 82 GPIO_ACTIVE_HIGH>;
+		num-interpolated-steps = <1023>;
+		pwms = <&disp_pwm0 0 500000>;
+		power-supply = <&ppvar_sys>;
+	};
+
 	chosen {
 		stdout-path = "serial0:115200n8";
 	};
@@ -349,6 +359,13 @@ &auxadc {
 	status = "okay";
 };
 
+&disp_pwm0 {
+	status = "okay";
+
+	pinctrl-names = "default";
+	pinctrl-0 = <&disp_pwm0_pin_default>;
+};
+
 &i2c0 {
 	status = "okay";
 
@@ -773,6 +790,13 @@ pins-cmd-dat {
 		};
 	};
 
+	disp_pwm0_pin_default: disp-pwm0-default-pins {
+		pins-disp-pwm {
+			pinmux = <PINMUX_GPIO82__FUNC_GPIO82>,
+				 <PINMUX_GPIO97__FUNC_DISP_PWM0>;
+		};
+	};
+
 	i2c0_pins: i2c0-default-pins {
 		pins-bus {
 			pinmux = <PINMUX_GPIO8__FUNC_SDA0>,
-- 
2.39.2