ACPI: add support for Smart Battery

Most batteries today are ACPI "Control Method" batteries,
but some models ship with the older "Smart Battery"
that requires this code.

Rich Townsend and Bruno Ducrot were the original authors.
Vladimir Lebedev updated to run on latest kernel.

http://bugzilla.kernel.org/show_bug.cgi?id=3734

Signed-off-by: Len Brown <len.brown@intel.com>

drivers/acpi/battery.c

@@ -59,6 +59,9 @@ ACPI_MODULE_NAME("acpi_battery")
 MODULE_DESCRIPTION(ACPI_BATTERY_DRIVER_NAME);
 MODULE_LICENSE("GPL");
 
+extern struct proc_dir_entry *acpi_lock_battery_dir(void);
+extern void *acpi_unlock_battery_dir(struct proc_dir_entry *acpi_battery_dir);
+
 static int acpi_battery_add(struct acpi_device *device);
 static int acpi_battery_remove(struct acpi_device *device, int type);
 
@@ -750,17 +753,15 @@ static int acpi_battery_remove(struct acpi_device *device, int type)
 
 static int __init acpi_battery_init(void)
 {
-	int result = 0;
+	int result;
 
-
-	acpi_battery_dir = proc_mkdir(ACPI_BATTERY_CLASS, acpi_root_dir);
+	acpi_battery_dir = acpi_lock_battery_dir();
 	if (!acpi_battery_dir)
 		return -ENODEV;
-	acpi_battery_dir->owner = THIS_MODULE;
 
 	result = acpi_bus_register_driver(&acpi_battery_driver);
 	if (result < 0) {
-		remove_proc_entry(ACPI_BATTERY_CLASS, acpi_root_dir);
+		acpi_unlock_battery_dir(acpi_battery_dir);
 		return -ENODEV;
 	}
 
@@ -772,7 +773,7 @@ static void __exit acpi_battery_exit(void)
 
 	acpi_bus_unregister_driver(&acpi_battery_driver);
 
-	remove_proc_entry(ACPI_BATTERY_CLASS, acpi_root_dir);
+	acpi_unlock_battery_dir(acpi_battery_dir);
 
 	return;
 }