rtc: at91sam9: add DT support

Add of_match_table to the existing driver so that rtt nodes defined in at91
DTs can be attached to this driver.

Signed-off-by: Boris BREZILLON <boris.brezillon@free-electrons.com>
Acked-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Acked-by: Johan Hovold <johan@kernel.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>

drivers/rtc/rtc-at91sam9.c

@@ -445,6 +445,14 @@ static int at91_rtc_resume(struct device *dev)
 
 static SIMPLE_DEV_PM_OPS(at91_rtc_pm_ops, at91_rtc_suspend, at91_rtc_resume);
 
+#ifdef CONFIG_OF
+static const struct of_device_id at91_rtc_dt_ids[] = {
+	{ .compatible = "atmel,at91sam9260-rtt" },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, at91_rtc_dt_ids);
+#endif
+
 static struct platform_driver at91_rtc_driver = {
 	.probe		= at91_rtc_probe,
 	.remove		= at91_rtc_remove,
@@ -453,6 +461,7 @@ static struct platform_driver at91_rtc_driver = {
 		.name	= "rtc-at91sam9",
 		.owner	= THIS_MODULE,
 		.pm	= &at91_rtc_pm_ops,
+		.of_match_table = of_match_ptr(at91_rtc_dt_ids),
 	},
 };