arm64: dts: renesas: r8a77995: draak: Add backlight

Add the backlight device for the LVDS1 output, in preparation for panel
support.
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

arch/arm64/boot/dts/renesas/r8a77995-draak.dts

@@ -24,6 +24,17 @@ chosen {
 		stdout-path = "serial0:115200n8";
 	};
 
+	backlight: backlight {
+		compatible = "pwm-backlight";
+		pwms = <&pwm1 0 50000>;
+
+		brightness-levels = <256 128 64 16 8 4 0>;
+		default-brightness-level = <6>;
+
+		power-supply = <&reg_12p0v>;
+		enable-gpios = <&gpio4 0 GPIO_ACTIVE_HIGH>;
+	};
+
 	composite-in {
 		compatible = "composite-video-connector";
 
@@ -104,6 +115,15 @@ reg_3p3v: regulator1 {
 		regulator-always-on;
 	};
 
+	reg_12p0v: regulator1 {
+		compatible = "regulator-fixed";
+		regulator-name = "D12.0V";
+		regulator-min-microvolt = <12000000>;
+		regulator-max-microvolt = <12000000>;
+		regulator-boot-on;
+		regulator-always-on;
+	};
+
 	vga {
 		compatible = "vga-connector";