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>
diff --git a/drivers/acpi/ac.c b/drivers/acpi/ac.c
index 4537ae4..e0a1b15 100644
--- a/drivers/acpi/ac.c
+++ b/drivers/acpi/ac.c
@@ -50,6 +50,9 @@
 MODULE_DESCRIPTION(ACPI_AC_DRIVER_NAME);
 MODULE_LICENSE("GPL");
 
+extern struct proc_dir_entry *acpi_lock_ac_dir(void);
+extern void *acpi_unlock_ac_dir(struct proc_dir_entry *acpi_ac_dir);
+
 static int acpi_ac_add(struct acpi_device *device);
 static int acpi_ac_remove(struct acpi_device *device, int type);
 static int acpi_ac_open_fs(struct inode *inode, struct file *file);
@@ -278,17 +281,16 @@
 
 static int __init acpi_ac_init(void)
 {
-	int result = 0;
+	int result;
 
 
-	acpi_ac_dir = proc_mkdir(ACPI_AC_CLASS, acpi_root_dir);
+	acpi_ac_dir = acpi_lock_ac_dir();
 	if (!acpi_ac_dir)
 		return -ENODEV;
-	acpi_ac_dir->owner = THIS_MODULE;
 
 	result = acpi_bus_register_driver(&acpi_ac_driver);
 	if (result < 0) {
-		remove_proc_entry(ACPI_AC_CLASS, acpi_root_dir);
+		acpi_unlock_ac_dir(acpi_ac_dir);
 		return -ENODEV;
 	}
 
@@ -300,7 +302,7 @@
 
 	acpi_bus_unregister_driver(&acpi_ac_driver);
 
-	remove_proc_entry(ACPI_AC_CLASS, acpi_root_dir);
+	acpi_unlock_ac_dir(acpi_ac_dir);
 
 	return;
 }