Input: arc_ps2 - add support for device tree

Add match table for device tree binding and dts binding doc.
Signed-off-by: NMischa Jonker <mjonker@synopsys.com>
Signed-off-by: NDmitry Torokhov <dmitry.torokhov@gmail.com>

Documentation/devicetree/bindings/serio/snps-arc_ps2.txt

+* ARC PS/2 driver: PS/2 block used in some ARC FPGA's & nSIM OSCI model
+
+Required properties:
+- compatible		: "snps,arc_ps2"
+- reg			: offset and length (always 0x14) of registers
+- interrupts		: interrupt
+- interrupt-names	: name of interrupt, must be "arc_ps2_irq"
+
+Example:
+
+serio@c9000400 {
+	compatible = "snps,arc_ps2";
+	reg = <0xc9000400 0x14>;
+	interrupts = <13>;
+	interrupt-names = "arc_ps2_irq";
+}

drivers/input/serio/arc_ps2.c

@@ -14,6 +14,7 @@
 #include <linux/input.h>
 #include <linux/serio.h>
 #include <linux/platform_device.h>
+#include <linux/of.h>
 #include <linux/io.h>
 #include <linux/kernel.h>
 #include <linux/slab.h>
@@ -259,10 +260,19 @@ static int arc_ps2_remove(struct platform_device *pdev)
 	return 0;
 }
 
+#ifdef CONFIG_OF
+static const struct of_device_id arc_ps2_match[] = {
+	{ .compatible = "snps,arc_ps2" },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, arc_ps2_match);
+#endif
+
 static struct platform_driver arc_ps2_driver = {
 	.driver	= {
 		.name		= "arc_ps2",
 		.owner		= THIS_MODULE,
+		.of_match_table	= of_match_ptr(arc_ps2_match),
 	},
 	.probe	= arc_ps2_probe,
 	.remove	= arc_ps2_remove,