[PATCH] pnp: PNP: adjust pnp_register_driver signature

Remove the assumption that pnp_register_driver() returns the number of devices
claimed.  Returning the count is unreliable because devices may be hot-plugged
in the future.

This changes the convention to "zero for success, or a negative error value,"
which matches pci_register_driver(), acpi_bus_register_driver(), and
platform_driver_register().

Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Cc: Adam Belay <ambx1@neo.rr.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

Documentation/pnp.txt

@@ -115,6 +115,9 @@ pnp_unregister_protocol
 pnp_register_driver
 - adds a PnP driver to the Plug and Play Layer
 - this includes driver model integration
+- returns zero for success or a negative error number for failure; count
+  calls to the .add() method if you need to know how many devices bind to
+  the driver
 
 pnp_unregister_driver
 - removes a PnP driver from the Plug and Play Layer

drivers/pnp/card.c

@@ -361,7 +361,7 @@ static int card_resume(struct pnp_dev *dev)
 
 int pnp_register_card_driver(struct pnp_card_driver * drv)
 {
-	int count;
+	int error;
 	struct list_head *pos, *temp;
 
 	drv->link.name = drv->name;
@@ -372,21 +372,19 @@ int pnp_register_card_driver(struct pnp_card_driver * drv)
 	drv->link.suspend = drv->suspend ? card_suspend : NULL;
 	drv->link.resume = drv->resume ? card_resume : NULL;
 
-	count = pnp_register_driver(&drv->link);
+	error = pnp_register_driver(&drv->link);
-	if (count < 0)
+	if (error < 0)
-		return count;
+		return error;
 
 	spin_lock(&pnp_lock);
 	list_add_tail(&drv->global_list, &pnp_card_drivers);
 	spin_unlock(&pnp_lock);
 
-	count = 0;
-
 	list_for_each_safe(pos,temp,&pnp_cards){
 		struct pnp_card *card = list_entry(pos, struct pnp_card, global_list);
-		count += card_probe(card,drv);
+		card_probe(card,drv);
 	}
-	return count;
+	return 0;
 }
 
 /**

drivers/pnp/driver.c

@@ -201,31 +201,14 @@ struct bus_type pnp_bus_type = {
 	.resume = pnp_bus_resume,
 };
 
-
-static int count_devices(struct device * dev, void * c)
-{
-	int * count = c;
-	(*count)++;
-	return 0;
-}
-
 int pnp_register_driver(struct pnp_driver *drv)
 {
-	int count;
-
 	pnp_dbg("the driver '%s' has been registered", drv->name);
 
 	drv->driver.name = drv->name;
 	drv->driver.bus = &pnp_bus_type;
 
-	count = driver_register(&drv->driver);
+	return driver_register(&drv->driver);
-
-	/* get the number of initial matches */
-	if (count >= 0){
-		count = 0;
-		driver_for_each_device(&drv->driver, NULL, &count, count_devices);
-	}
-	return count;
 }
 
 void pnp_unregister_driver(struct pnp_driver *drv)