watchdog: dw: Enable OF support for DW watchdog timer

Add device tree support to the DW watchdog timer.
Signed-off-by: Dinh Nguyen <dinguyen@altera.com>
Acked-by: Jamie Iles <jamie@jamieiles.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Pavel Machek <pavel@denx.de>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Cc: Viresh Kumar <viresh.linux@gmail.com>
Cc: Rob Herring <rob.herring@calxeda.com>
Cc: Pawel Moll <pawel.moll@arm.com>
Cc: Stephen Warren <swarren@wwwdotorg.org>
Cc: Ian Campbell <ijc+devicetree@hellion.org.uk>
Cc: devicetree@vger.kernel.org
Cc: linux-watchdog@vger.kernel.org

Documentation/devicetree/bindings/watchdog/dw_wdt.txt

+Synopsys Designware Watchdog Timer
+
+Required Properties:
+
+- compatible	: Should contain "snps,dw-wdt"
+- reg		: Base address and size of the watchdog timer registers.
+- clocks	: phandle + clock-specifier for the clock that drives the
+		watchdog timer.
+
+Optional Properties:
+
+- interrupts	: The interrupt used for the watchdog timeout warning.
+
+Example:
+
+	watchdog0: wd@ffd02000 {
+		compatible = "snps,dw-wdt";
+		reg = <0xffd02000 0x1000>;
+		interrupts = <0 171 4>;
+		clocks = <&per_base_clk>;
+	};

drivers/watchdog/dw_wdt.c

@@ -29,6 +29,7 @@
 #include <linux/miscdevice.h>
 #include <linux/module.h>
 #include <linux/moduleparam.h>
+#include <linux/of.h>
 #include <linux/pm.h>
 #include <linux/platform_device.h>
 #include <linux/spinlock.h>
@@ -337,12 +338,21 @@ static int dw_wdt_drv_remove(struct platform_device *pdev)
 	return 0;
 }
 
+#ifdef CONFIG_OF
+static const struct of_device_id dw_wdt_of_match[] = {
+	{ .compatible = "snps,dw-wdt", },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, dw_wdt_of_match);
+#endif
+
 static struct platform_driver dw_wdt_driver = {
 	.probe		= dw_wdt_drv_probe,
 	.remove		= dw_wdt_drv_remove,
 	.driver		= {
 		.name	= "dw_wdt",
 		.owner	= THIS_MODULE,
+		.of_match_table = of_match_ptr(dw_wdt_of_match),
 		.pm	= &dw_wdt_pm_ops,
 	},
 };