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

Add support to Rocktech RK043FN48H display on stm32f746-disco board.
Signed-off-by: Dario Binacchi <dario.binacchi@amarulasolutions.com>
Reviewed-by: Raphaël Gallais-Pou <raphael.gallais-pou@foss.st.com>
Signed-off-by: Alexandre Torgue <alexandre.torgue@foss.st.com>

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

@@ -61,6 +61,19 @@ memory@c0000000 {
 		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;
 	};
@@ -86,6 +99,25 @@ vcc_3v3: 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>;
+			};
+		};
+	};
 };
 
 &clk_hse {
@@ -116,6 +148,18 @@ touchscreen@38 {
 	};
 };
 
+&ltdc {
+	pinctrl-0 = <&ltdc_pins_a>;
+	pinctrl-names = "default";
+	status = "okay";
+
+	port {
+		ltdc_out_rgb: endpoint {
+			remote-endpoint = <&panel_in_rgb>;
+		};
+	};
+};
+
 &sdio1 {
 	status = "okay";
 	vmmc-supply = <&vcc_3v3>;