watchdog: JZ4740: Register a restart handler

The watchdog driver can restart the system by simply configuring the
hardware for a timeout of 0 seconds.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Cc: Wim Van Sebroeck <wim@linux-watchdog.org>
Cc: Mathieu Malaterre <malat@debian.org>
Cc: linux-watchdog@vger.kernel.org
Cc: linux-mips@linux-mips.org
Signed-off-by: James Hogan <jhogan@kernel.org>

drivers/watchdog/jz4740_wdt.c

@@ -130,6 +130,14 @@ static int jz4740_wdt_stop(struct watchdog_device *wdt_dev)
 	return 0;
 }
 
+static int jz4740_wdt_restart(struct watchdog_device *wdt_dev,
+			      unsigned long action, void *data)
+{
+	wdt_dev->timeout = 0;
+	jz4740_wdt_start(wdt_dev);
+	return 0;
+}
+
 static const struct watchdog_info jz4740_wdt_info = {
 	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
 	.identity = "jz4740 Watchdog",
@@ -141,6 +149,7 @@ static const struct watchdog_ops jz4740_wdt_ops = {
 	.stop = jz4740_wdt_stop,
 	.ping = jz4740_wdt_ping,
 	.set_timeout = jz4740_wdt_set_timeout,
+	.restart = jz4740_wdt_restart,
 };
 
 #ifdef CONFIG_OF