drivers/rtc/rtc-isl12022.c: device tree support

Add support for configuring the ISL12022 real-time clock via the Device
tree framework.  This is based on what I've seen in the related ISL12057
driver, it has been tested and works on a Technologic Systems TS-7670
device which uses a ISL12020 RTC device, my device tree looks like this:

	apbx@80040000 {
		i2c0: i2c@80058000 {
			pinctrl-names = "default";
			pinctrl-0 = <&i2c0_pins_a>;
			clock-frequency = <400000>;
			status = "okay";

			isl12022@0x6f {
				compatible = "isl,isl12022";
				reg = <0x6f>;
			};
		};
		... etc
	};

Signed-off-by: Stuart Longland <stuartl@vrt.com.au>
Cc: Roman Fietze <roman.fietze@telemotive.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/rtc/rtc-isl12022.c

@@ -17,6 +17,8 @@
 #include <linux/slab.h>
 #include <linux/module.h>
 #include <linux/err.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
 
 #define DRV_VERSION "0.1"
 
@@ -271,6 +273,13 @@ static int isl12022_probe(struct i2c_client *client,
 	return PTR_ERR_OR_ZERO(isl12022->rtc);
 }
 
+#ifdef CONFIG_OF
+static struct of_device_id isl12022_dt_match[] = {
+	{ .compatible = "isl,isl12022" },
+	{ },
+};
+#endif
+
 static const struct i2c_device_id isl12022_id[] = {
 	{ "isl12022", 0 },
 	{ }
@@ -280,6 +289,9 @@ MODULE_DEVICE_TABLE(i2c, isl12022_id);
 static struct i2c_driver isl12022_driver = {
 	.driver		= {
 		.name	= "rtc-isl12022",
+#ifdef CONFIG_OF
+		.of_match_table = of_match_ptr(isl12022_dt_match),
+#endif
 	},
 	.probe		= isl12022_probe,
 	.id_table	= isl12022_id,