Input: add serio->start() and serio->stop() callback methods that

       are called whenever serio port is finishes being registered
       or unregistered. The callbacks are useful for drivers that
       share interrupt between several ports and there is a danger
       that interrupt handler will reference port that was just
       unregistered.
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
Signed-off-by: Vojtech Pavlik <vojtech@suse.cz>

drivers/input/serio/serio.c

@@ -326,7 +326,10 @@ static void serio_create_port(struct serio *serio)
 	serio->dev.release = serio_release_port;
 	if (serio->parent)
 		serio->dev.parent = &serio->parent->dev;
-	device_register(&serio->dev);
+	device_initialize(&serio->dev);
+	if (serio->start)
+		serio->start(serio);
+	device_add(&serio->dev);
 }
 
 /*
@@ -349,6 +352,9 @@ static void serio_destroy_port(struct serio *serio)
 		put_driver(&drv->driver);
 	}
 
+	if (serio->stop)
+		serio->stop(serio);
+
 	if (serio->parent) {
 		spin_lock_irqsave(&serio->parent->lock, flags);
 		serio->parent->child = NULL;

include/linux/serio.h

@@ -42,6 +42,8 @@ struct serio {
 	int (*write)(struct serio *, unsigned char);
 	int (*open)(struct serio *);
 	void (*close)(struct serio *);
+	int (*start)(struct serio *);
+	void (*stop)(struct serio *);
 
 	struct serio *parent, *child;