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>

drivers/extcon/extcon-class.c

@@ -819,6 +819,75 @@ void extcon_dev_unregister(struct extcon_dev *edev)
 }
 EXPORT_SYMBOL_GPL(extcon_dev_unregister);
 
+static void devm_extcon_dev_unreg(struct device *dev, void *res)
+{
+	extcon_dev_unregister(*(struct extcon_dev **)res);
+}
+
+static int devm_extcon_dev_match(struct device *dev, void *res, void *data)
+{
+	struct extcon_dev **r = res;
+
+	if (!r || !*r) {
+		WARN_ON(!r || !*r);
+		return 0;
+	}
+
+	return *r == data;
+}
+
+/**
+ * devm_extcon_dev_register() - Resource-managed extcon_dev_register()
+ * @dev:	device to allocate extcon device
+ * @edev:	the new extcon device to register
+ *
+ * Managed extcon_dev_register() function. If extcon device is attached with
+ * this function, that extcon device is automatically unregistered on driver
+ * detach. Internally this function calls extcon_dev_register() function.
+ * To get more information, refer that function.
+ *
+ * If extcon device is registered with this function and the device needs to be
+ * unregistered separately, devm_extcon_dev_unregister() should be used.
+ *
+ * Returns 0 if success or negaive error number if failure.
+ */
+int devm_extcon_dev_register(struct device *dev, struct extcon_dev *edev)
+{
+	struct extcon_dev **ptr;
+	int ret;
+
+	ptr = devres_alloc(devm_extcon_dev_unreg, sizeof(*ptr), GFP_KERNEL);
+	if (!ptr)
+		return -ENOMEM;
+
+	ret = extcon_dev_register(edev);
+	if (ret) {
+		devres_free(ptr);
+		return ret;
+	}
+
+	*ptr = edev;
+	devres_add(dev, ptr);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(devm_extcon_dev_register);
+
+/**
+ * devm_extcon_dev_unregister() - Resource-managed extcon_dev_unregister()
+ * @dev:	device the extcon belongs to
+ * @edev:	the extcon device to unregister
+ *
+ * Unregister extcon device that is registered with devm_extcon_dev_register()
+ * function.
+ */
+void devm_extcon_dev_unregister(struct device *dev, struct extcon_dev *edev)
+{
+	WARN_ON(devres_release(dev, devm_extcon_dev_unreg,
+			       devm_extcon_dev_match, edev));
+}
+EXPORT_SYMBOL_GPL(devm_extcon_dev_unregister);
+
 #ifdef CONFIG_OF
 /*
  * extcon_get_edev_by_phandle - Get the extcon device from devicetree

include/linux/extcon.h

@@ -185,6 +185,10 @@ struct extcon_specific_cable_nb {
  */
 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 int extcon_dev_register(struct extcon_dev *edev)
 
 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;