extcon: Update the prototype of extcon_register_notifier() with enum extcon

Previously, extcon consumer driver used the extcon_register_interest()
to register the notifier chain and then to receive the notifier event
when external connector's state is changed. When registering the notifier chain
for specific external connector with extcon_register_interest(), it used the
the string name of external connector directly. There are potential problem
because of unclear, non-standard and inconsequent cable name. Namely,
it is not appropriate method to identify each external connector.

So, this patch modify the prototype of extcon_register_notifier() by using
the 'enum extcon' which are the unique id for each external connector
instead of unclear string method.

- Previously, the extcon consumer driver used the extcon_register_interest()
with 'cable_name' to point out the specific external connector. Also. it used
the un-needed structure (struct extcon_specific_cable_nb).
: int extcon_register_interest(struct extcon_specific_cable_nb *obj,
			     const char *extcon_name, const char *cable_name,
			     struct notifier_block *nb)

- Newly, the updated extcon_register_notifier() would definitely support
the same feature to detech the changed state of external connector without
any specific structure (struct extcon_specific_cable_nb).
: int extcon_register_notifier(struct extcon_dev *edev, enum extcon id,
			     struct notifier_block *nb)

This patch support the both extcon_register_interest() and new extcon_register_
notifier(). But the extcon_{register|unregister}_interest() will be deprecated
because extcon core would support the notifier event for extcon consumer driver
with only updated extcon_register_notifier() and 'extcon_specific_cable_nb'
will be removed if there are no extcon consumer driver with legacy
extcon_{register|unregister}_interest().

Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>

1 files changed, 8 insertions, 9 deletions

diff --git a/include/linux/extcon.h b/include/linux/extcon.h
index 85c882f0029e..be9652b3a154 100644
--- a/include/linux/extcon.h
+++ b/include/linux/extcon.h
@@ -116,7 +116,7 @@ struct extcon_dev {
 
 	/* Internal data. Please do not set. */
 	struct device dev;
-	struct raw_notifier_head nh;
+	struct raw_notifier_head *nh;
 	struct list_head entry;
 	int max_supported;
 	spinlock_t lock;	/* could be called by irq handler */
@@ -155,8 +155,6 @@ struct extcon_cable {
 /**
  * struct extcon_specific_cable_nb - An internal data for
  *				     extcon_register_interest().
- * @internal_nb:	A notifier block bridging extcon notifier
- *			and cable notifier.
  * @user_nb:		user provided notifier block for events from
  *			a specific cable.
  * @cable_index:	the target cable.
@@ -164,7 +162,6 @@ struct extcon_cable {
  * @previous_value:	the saved previous event value.
  */
 struct extcon_specific_cable_nb {
-	struct notifier_block internal_nb;
 	struct notifier_block *user_nb;
 	int cable_index;
 	struct extcon_dev *edev;
@@ -240,10 +237,10 @@ extern int extcon_unregister_interest(struct extcon_specific_cable_nb *nb);
  * we do not recommend to use this for normal 'notifiee' device drivers who
  * want to be notified by a specific external port of the notifier.
  */
-extern int extcon_register_notifier(struct extcon_dev *edev,
+extern int extcon_register_notifier(struct extcon_dev *edev, enum extcon id,
+				    struct notifier_block *nb);
+extern int extcon_unregister_notifier(struct extcon_dev *edev, enum extcon id,
 				    struct notifier_block *nb);
-extern int extcon_unregister_notifier(struct extcon_dev *edev,
-				      struct notifier_block *nb);
 
 /*
  * Following API get the extcon device from devicetree.
@@ -333,13 +330,15 @@ static inline struct extcon_dev *extcon_get_extcon_dev(const char *extcon_name)
 }
 
 static inline int extcon_register_notifier(struct extcon_dev *edev,
-					   struct notifier_block *nb)
+					enum extcon id,
+					struct notifier_block *nb)
 {
 	return 0;
 }
 
 static inline int extcon_unregister_notifier(struct extcon_dev *edev,
-					     struct notifier_block *nb)
+					enum extcon id,
+					struct notifier_block *nb)
 {
 	return 0;
 }