kernel/reboot: Add devm_register_restart_handler()

Add devm_register_restart_handler() helper that registers sys-off
handler using restart mode and with a default priority. Most drivers
will want to register restart handler with a default priority, so this
helper will reduce the boilerplate code and make code easier to read and
follow.

Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Author: digetx

include/linux/reboot.h

@@ -145,6 +145,10 @@ int devm_register_power_off_handler(struct device *dev,
 				    int (*callback)(struct sys_off_data *data),
 				    void *cb_data);
 
+int devm_register_restart_handler(struct device *dev,
+				  int (*callback)(struct sys_off_data *data),
+				  void *cb_data);
+
 int register_platform_power_off(void (*power_off)(void));
 void unregister_platform_power_off(void (*power_off)(void));
 

kernel/reboot.c

@@ -484,6 +484,28 @@ int devm_register_power_off_handler(struct device *dev,
 }
 EXPORT_SYMBOL_GPL(devm_register_power_off_handler);
 
+/**
+ *	devm_register_restart_handler - Register restart handler
+ *	@dev: Device that registers callback
+ *	@callback: Callback function
+ *	@cb_data: Callback's argument
+ *
+ *	Registers resource-managed sys-off handler with a default priority
+ *	and using restart mode.
+ *
+ *	Returns zero on success, or error code on failure.
+ */
+int devm_register_restart_handler(struct device *dev,
+				  int (*callback)(struct sys_off_data *data),
+				  void *cb_data)
+{
+	return devm_register_sys_off_handler(dev,
+					     SYS_OFF_MODE_RESTART,
+					     SYS_OFF_PRIO_DEFAULT,
+					     callback, cb_data);
+}
+EXPORT_SYMBOL_GPL(devm_register_restart_handler);
+
 static struct sys_off_handler *platform_power_off_handler;
 
 static int platform_power_off_notify(struct sys_off_data *data)