ARM: dts: am335x-icev2: Add nodes for gpio-decoder

AM335x ICE board has a rotary-switch connected to PCA9536 I2C GPIO
expander. The position of the rotary-switch is reflected by status of
GPIO lines. Add gpio-decoder node to read these GPIO line status via
gpio-decoder driver and report it as an input event to the system.

Signed-off-by: Vignesh R <vigneshr@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

arch/arm/boot/dts/am335x-icev2.dts

@@ -139,6 +139,15 @@
 			default-state = "off";
 		};
 	};
+	gpio-decoder {
+		compatible = "gpio-decoder";
+		gpios = <&pca9536 3 GPIO_ACTIVE_HIGH>,
+			<&pca9536 2 GPIO_ACTIVE_HIGH>,
+			<&pca9536 1 GPIO_ACTIVE_HIGH>,
+			<&pca9536 0 GPIO_ACTIVE_HIGH>;
+		linux,axis = <0>; /* ABS_X */
+		decoder-max-value = <9>;
+	};
 };
 
 &am33xx_pinmux {