ARM: dts: imx: add LVDS backlight for Ventana

The GW54xx/GW53xx/GW52xx all support LVDS with a PWM controlled backlight.

Signed-off-by: Tim Harvey <tharvey@gateworks.com>
Signed-off-by: Shawn Guo <shawn.guo@freescale.com>
diff --git a/arch/arm/boot/dts/imx6qdl-gw52xx.dtsi b/arch/arm/boot/dts/imx6qdl-gw52xx.dtsi
index 1022197..62f533a 100644
--- a/arch/arm/boot/dts/imx6qdl-gw52xx.dtsi
+++ b/arch/arm/boot/dts/imx6qdl-gw52xx.dtsi
@@ -27,6 +27,13 @@
 		bootargs = "console=ttymxc1,115200";
 	};
 
+	backlight {
+		compatible = "pwm-backlight";
+		pwms = <&pwm4 0 5000000>;
+		brightness-levels = <0 4 8 16 32 64 128 255>;
+		default-brightness-level = <7>;
+	};
+
 	leds {
 		compatible = "gpio-leds";
 
@@ -399,6 +406,12 @@
 			>;
 		};
 
+		pinctrl_pwm4: pwm4grp {
+			fsl,pins = <
+				MX6QDL_PAD_SD1_CMD__PWM4_OUT		0x1b0b1
+			>;
+		};
+
 		pinctrl_uart1: uart1grp {
 			fsl,pins = <
 				MX6QDL_PAD_SD3_DAT7__UART1_TX_DATA	0x1b0b1
@@ -448,6 +461,12 @@
 	status = "okay";
 };
 
+&pwm4 {
+	pinctrl-names = "default";
+	pinctrl-0 = <&pinctrl_pwm4>;
+	status = "okay";
+};
+
 &ssi1 {
 	fsl,mode = "i2s-slave";
 	status = "okay";