watchdog: gpio_wdt: use core reboot notifier

Get rid of the custom reboot notifier block registration and use the one
provided by the watchdog core.

Note that this watchdog used to stop unconditionnaly on SYS_HALT and
SYS_POWER_OFF. The core function now calls ops->stop on SYS_HALT and
SYS_DOWN. To prevent the watchdog from being stopped on reboot, the
"always-running" property must be set, otherwise it will now be stopped.

Signed-off-by: Damien Riegel <damien.riegel@savoirfairelinux.com>
Reviewed-by: Vivien Didelot <vivien.didelot@savoirlinux.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

drivers/watchdog/gpio_wdt.c

@@ -12,10 +12,8 @@
 #include <linux/err.h>
 #include <linux/delay.h>
 #include <linux/module.h>
-#include <linux/notifier.h>
 #include <linux/of_gpio.h>
 #include <linux/platform_device.h>
-#include <linux/reboot.h>
 #include <linux/watchdog.h>
 
 #define SOFT_TIMEOUT_MIN	1
@@ -36,7 +34,6 @@ struct gpio_wdt_priv {
 	unsigned int		hw_algo;
 	unsigned int		hw_margin;
 	unsigned long		last_jiffies;
-	struct notifier_block	notifier;
 	struct timer_list	timer;
 	struct watchdog_device	wdd;
 };
@@ -126,26 +123,6 @@ static int gpio_wdt_set_timeout(struct watchdog_device *wdd, unsigned int t)
 	return gpio_wdt_ping(wdd);
 }
 
-static int gpio_wdt_notify_sys(struct notifier_block *nb, unsigned long code,
-			       void *unused)
-{
-	struct gpio_wdt_priv *priv = container_of(nb, struct gpio_wdt_priv,
-						  notifier);
-
-	mod_timer(&priv->timer, 0);
-
-	switch (code) {
-	case SYS_HALT:
-	case SYS_POWER_OFF:
-		gpio_wdt_disable(priv);
-		break;
-	default:
-		break;
-	}
-
-	return NOTIFY_DONE;
-}
-
 static const struct watchdog_info gpio_wdt_ident = {
 	.options	= WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING |
 			  WDIOF_SETTIMEOUT,
@@ -224,23 +201,16 @@ static int gpio_wdt_probe(struct platform_device *pdev)
 
 	setup_timer(&priv->timer, gpio_wdt_hwping, (unsigned long)&priv->wdd);
 
+	watchdog_stop_on_reboot(&priv->wdd);
+
 	ret = watchdog_register_device(&priv->wdd);
 	if (ret)
 		return ret;
 
-	priv->notifier.notifier_call = gpio_wdt_notify_sys;
-	ret = register_reboot_notifier(&priv->notifier);
-	if (ret)
-		goto error_unregister;
-
 	if (priv->always_running)
 		gpio_wdt_start_impl(priv);
 
 	return 0;
-
-error_unregister:
-	watchdog_unregister_device(&priv->wdd);
-	return ret;
 }
 
 static int gpio_wdt_remove(struct platform_device *pdev)
@@ -248,7 +218,6 @@ static int gpio_wdt_remove(struct platform_device *pdev)
 	struct gpio_wdt_priv *priv = platform_get_drvdata(pdev);
 
 	del_timer_sync(&priv->timer);
-	unregister_reboot_notifier(&priv->notifier);
 	watchdog_unregister_device(&priv->wdd);
 
 	return 0;