arm64: dts: renesas: r8a77990: ebisu: 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: Ulrich Hecht <uli+renesas@fpond.eu>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

arch/arm64/boot/dts/renesas/r8a77990-ebisu.dts

@@ -39,6 +39,16 @@
 		clock-frequency = <11289600>;
 	};
 
+	backlight: backlight {
+		compatible = "pwm-backlight";
+		pwms = <&pwm3 0 50000>;
+
+		brightness-levels = <512 511 505 494 473 440 392 327 241 133 0>;
+		default-brightness-level = <10>;
+
+		power-supply = <&reg_12p0v>;
+	};
+
 	cvbs-in {
 		compatible = "composite-video-connector";
 		label = "CVBS IN";
@@ -184,6 +194,15 @@
 		clock-frequency = <24576000>;
 	};
 
+	reg_12p0v: regulator1 {
+		compatible = "regulator-fixed";
+		regulator-name = "D12.0V";
+		regulator-min-microvolt = <12000000>;
+		regulator-max-microvolt = <12000000>;
+		regulator-boot-on;
+		regulator-always-on;
+	};
+
 	x13_clk: x13 {
 		compatible = "fixed-clock";
 		#clock-cells = <0>;