ARM: dts: stm32: support display on stm32f746-disco board

Add support to Rocktech RK043FN48H display on stm32f746-disco board.

Signed-off-by: Dario Binacchi <[e-mail]>
Reviewed-by: Raphaël Gallais-Pou <[e-mail]>
Signed-off-by: Alexandre Torgue <[e-mail]>

arch/arm/boot/dts/st/stm32f746-disco.dts

···
 		reg = <0xC0000000 0x800000>;
 	};
 
+	reserved-memory {
+		#address-cells = <1>;
+		#size-cells = <1>;
+		ranges;
+
+		linux,cma {
+			compatible = "shared-dma-pool";
+			no-map;
+			size = <0x80000>;
+			linux,dma-default;
+		};
+	};
+
 	aliases {
 		serial0 = &usart1;
 	};
···
 		regulator-name = "vcc_3v3";
 		regulator-min-microvolt = <3300000>;
 		regulator-max-microvolt = <3300000>;
+	};
+
+	backlight: backlight {
+		compatible = "gpio-backlight";
+		gpios = <&gpiok 3 GPIO_ACTIVE_HIGH>;
+		status = "okay";
+	};
+
+	panel_rgb: panel-rgb {
+		compatible = "rocktech,rk043fn48h";
+		power-supply = <&vcc_3v3>;
+		backlight = <&backlight>;
+		enable-gpios = <&gpioi 12 GPIO_ACTIVE_HIGH>;
+		status = "okay";
+		port {
+			panel_in_rgb: endpoint {
+				remote-endpoint = <&ltdc_out_rgb>;
+			};
+		};
 	};
 };
 
···
 		interrupts = <13 IRQ_TYPE_EDGE_FALLING>;
 		touchscreen-size-x = <480>;
 		touchscreen-size-y = <272>;
+	};
+};
+
+&ltdc {
+	pinctrl-0 = <&ltdc_pins_a>;
+	pinctrl-names = "default";
+	status = "okay";
+
+	port {
+		ltdc_out_rgb: endpoint {
+			remote-endpoint = <&panel_in_rgb>;
+		};
 	};
 };