extcon: Add resource-managed extcon register function

Add resource-managed extcon device register function for convenience.
For example, if a extcon device is attached with new
devm_extcon_dev_register(), that extcon device is automatically
unregistered on driver detach.

Signed-off-by: Sangjung Woo <sangjung.woo@samsung.com>
[Fix bug about devm_extcon_dev_match/release() and code clean by Chanwoo Choi]
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
diff --git a/include/linux/extcon.h b/include/linux/extcon.h
index f488145..548447b 100644
--- a/include/linux/extcon.h
+++ b/include/linux/extcon.h
@@ -185,6 +185,10 @@
  */
 extern int extcon_dev_register(struct extcon_dev *edev);
 extern void extcon_dev_unregister(struct extcon_dev *edev);
+extern int devm_extcon_dev_register(struct device *dev,
+				    struct extcon_dev *edev);
+extern void devm_extcon_dev_unregister(struct device *dev,
+				       struct extcon_dev *edev);
 extern struct extcon_dev *extcon_get_extcon_dev(const char *extcon_name);
 
 /*
@@ -254,6 +258,15 @@
 
 static inline void extcon_dev_unregister(struct extcon_dev *edev) { }
 
+static inline int devm_extcon_dev_register(struct device *dev,
+					   struct extcon_dev *edev)
+{
+	return -EINVAL;
+}
+
+static inline void devm_extcon_dev_unregister(struct device *dev,
+					      struct extcon_dev *edev) { }
+
 static inline u32 extcon_get_state(struct extcon_dev *edev)
 {
 	return 0;