arm64: dts: k3-j721e: Add gpio-keys on common processor board

Common processor board for K3 J721E platform has two push buttons
namely SW10 and SW11.
Add a gpio-keys device node to model them as input keys in Linux.
Add required pinmux nodes to set GPIO pins as input.
Signed-off-by: Nikhil Devshatwar <nikhil.nd@ti.com>
Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
Reviewed-by: Keerthy <j-keerthy@ti.com>
Signed-off-by: Tero Kristo <t-kristo@ti.com>

arch/arm64/boot/dts/ti/k3-j721e-common-proc-board.dts

@@ -6,12 +6,49 @@
 /dts-v1/;
 
 #include "k3-j721e-som-p0.dtsi"
+#include <dt-bindings/gpio/gpio.h>
+#include <dt-bindings/input/input.h>
 
 / {
 	chosen {
 		stdout-path = "serial2:115200n8";
 		bootargs = "console=ttyS2,115200n8 earlycon=ns16550a,mmio32,0x02800000";
 	};
+
+	gpio_keys: gpio-keys {
+		compatible = "gpio-keys";
+		autorepeat;
+		pinctrl-names = "default";
+		pinctrl-0 = <&sw10_button_pins_default &sw11_button_pins_default>;
+
+		sw10: sw10 {
+			label = "GPIO Key USER1";
+			linux,code = <BTN_0>;
+			gpios = <&main_gpio0 0 GPIO_ACTIVE_LOW>;
+		};
+
+		sw11: sw11 {
+			label = "GPIO Key USER2";
+			linux,code = <BTN_1>;
+			gpios = <&wkup_gpio0 7 GPIO_ACTIVE_LOW>;
+		};
+	};
+};
+
+&main_pmx0 {
+	sw10_button_pins_default: sw10_button_pins_default {
+		pinctrl-single,pins = <
+			J721E_IOPAD(0x0, PIN_INPUT, 7) /* (AC18) EXTINTn.GPIO0_0 */
+		>;
+	};
+};
+
+&wkup_pmx0 {
+	sw11_button_pins_default: sw11_button_pins_default {
+		pinctrl-single,pins = <
+			J721E_WKUP_IOPAD(0xcc, PIN_INPUT, 7) /* (G28) WKUP_GPIO0_7 */
+		>;
+	};
 };
 
 &wkup_uart0 {