extcon: Correct description to improve the readability

The extcon files explains the detailed operation for functions and
what is meaning of extcon structure. There are different explanation
even if the same argument.

So, it modifies the description for both functions and structures
in order to improve the readability and guide the role of functions
more well.

Also, this patch fixes the mismatching license info as a GPL v2
and removes the inactive author information.
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>

drivers/extcon/devres.c

 /*
- *  drivers/extcon/devres.c - EXTCON device's resource management
+ * drivers/extcon/devres.c - EXTCON device's resource management
  *
  * Copyright (C) 2016 Samsung Electronics
  * Author: Chanwoo Choi <cw00.choi@samsung.com>
@@ -59,10 +59,9 @@ static void devm_extcon_dev_notifier_all_unreg(struct device *dev, void *res)
 
 /**
  * devm_extcon_dev_allocate - Allocate managed extcon device
- * @dev:		device owning the extcon device being created
- * @supported_cable:	Array of supported extcon ending with EXTCON_NONE.
- *			If supported_cable is NULL, cable name related APIs
- *			are disabled.
+ * @dev:		the device owning the extcon device being created
+ * @supported_cable:	the array of the supported external connectors
+ *			ending with EXTCON_NONE.
  *
  * This function manages automatically the memory of extcon device using device
  * resource management and simplify the control of freeing the memory of extcon
@@ -97,8 +96,8 @@ EXPORT_SYMBOL_GPL(devm_extcon_dev_allocate);
 
 /**
  * devm_extcon_dev_free() - Resource-managed extcon_dev_unregister()
- * @dev:	device the extcon belongs to
- * @edev:	the extcon device to unregister
+ * @dev:	the device owning the extcon device being created
+ * @edev:	the extcon device to be freed
  *
  * Free the memory that is allocated with devm_extcon_dev_allocate()
  * function.
@@ -112,10 +111,9 @@ EXPORT_SYMBOL_GPL(devm_extcon_dev_free);
 
 /**
  * devm_extcon_dev_register() - Resource-managed extcon_dev_register()
- * @dev:	device to allocate extcon device
- * @edev:	the new extcon device to register
+ * @dev:	the device owning the extcon device being created
+ * @edev:	the extcon device to be registered
  *
- * 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.
@@ -149,8 +147,8 @@ 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
+ * @dev:	the device owning the extcon device being created
+ * @edev:	the extcon device to unregistered
  *
  * Unregister extcon device that is registered with devm_extcon_dev_register()
  * function.
@@ -164,10 +162,10 @@ EXPORT_SYMBOL_GPL(devm_extcon_dev_unregister);
 
 /**
  * devm_extcon_register_notifier() - Resource-managed extcon_register_notifier()
- * @dev:	device to allocate extcon device
- * @edev:	the extcon device that has the external connecotr.
- * @id:		the unique id of each external connector in extcon enumeration.
- * @nb:		a notifier block to be registered.
+ * @dev:	the device owning the extcon device being created
+ * @edev:	the extcon device
+ * @id:		the unique id among the extcon enumeration
+ * @nb:		a notifier block to be registered
  *
  * This function manages automatically the notifier of extcon device using
  * device resource management and simplify the control of unregistering
@@ -208,10 +206,10 @@ EXPORT_SYMBOL(devm_extcon_register_notifier);
 /**
  * devm_extcon_unregister_notifier()
 			- Resource-managed extcon_unregister_notifier()
- * @dev:	device to allocate extcon device
- * @edev:	the extcon device that has the external connecotr.
- * @id:		the unique id of each external connector in extcon enumeration.
- * @nb:		a notifier block to be registered.
+ * @dev:	the device owning the extcon device being created
+ * @edev:	the extcon device
+ * @id:		the unique id among the extcon enumeration
+ * @nb:		a notifier block to be registered
  */
 void devm_extcon_unregister_notifier(struct device *dev,
 				struct extcon_dev *edev, unsigned int id,
@@ -225,9 +223,9 @@ EXPORT_SYMBOL(devm_extcon_unregister_notifier);
 /**
  * devm_extcon_register_notifier_all()
  *		- Resource-managed extcon_register_notifier_all()
- * @dev:	device to allocate extcon device
- * @edev:	the extcon device that has the external connecotr.
- * @nb:		a notifier block to be registered.
+ * @dev:	the device owning the extcon device being created
+ * @edev:	the extcon device
+ * @nb:		a notifier block to be registered
  *
  * This function manages automatically the notifier of extcon device using
  * device resource management and simplify the control of unregistering
@@ -263,9 +261,9 @@ EXPORT_SYMBOL(devm_extcon_register_notifier_all);
 /**
  * devm_extcon_unregister_notifier_all()
  *		- Resource-managed extcon_unregister_notifier_all()
- * @dev:	device to allocate extcon device
- * @edev:	the extcon device that has the external connecotr.
- * @nb:		a notifier block to be registered.
+ * @dev:	the device owning the extcon device being created
+ * @edev:	the extcon device
+ * @nb:		a notifier block to be registered
  */
 void devm_extcon_unregister_notifier_all(struct device *dev,
 				struct extcon_dev *edev,

include/linux/extcon.h

 /*
- *  External connector (extcon) class driver
+ * External Connector (extcon) framework
  *
  * Copyright (C) 2015 Samsung Electronics
  * Author: Chanwoo Choi <cw00.choi@samsung.com>
@@ -20,8 +20,7 @@
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
- *
-*/
+ */
 
 #ifndef __LINUX_EXTCON_H__
 #define __LINUX_EXTCON_H__
@@ -93,7 +92,7 @@
 #define EXTCON_NUM		63
 
 /*
- * Define the property of supported external connectors.
+ * Define the properties of supported external connectors.
  *
  * When adding the new extcon property, they *must* have
  * the type/value/default information. Also, you *have to*
@@ -176,44 +175,42 @@ struct extcon_dev;
 
 #if IS_ENABLED(CONFIG_EXTCON)
 
-/*
- * Following APIs are for notifiers or configurations.
- * Notifiers are the external port and connection devices.
- */
+/* Following APIs register/unregister the extcon device. */
 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);
 
-/*
- * Following APIs control the memory of extcon device.
- */
+/* Following APIs allocate/free the memory of the extcon device. */
 extern struct extcon_dev *extcon_dev_allocate(const unsigned int *cable);
 extern void extcon_dev_free(struct extcon_dev *edev);
 extern struct extcon_dev *devm_extcon_dev_allocate(struct device *dev,
 						   const unsigned int *cable);
 extern void devm_extcon_dev_free(struct device *dev, struct extcon_dev *edev);
 
+/* Synchronize the state and property value for each external connector. */
+extern int extcon_sync(struct extcon_dev *edev, unsigned int id);
+
 /*
- * get/set_state access each bit of the 32b encoded state value.
- * They are used to access the status of each cable based on the cable id.
+ * Following APIs get/set the connected state of each external connector.
+ * The 'id' argument indicates the defined external connector.
  */
 extern int extcon_get_state(struct extcon_dev *edev, unsigned int id);
 extern int extcon_set_state(struct extcon_dev *edev, unsigned int id,
-				   bool cable_state);
+				   bool state);
 extern int extcon_set_state_sync(struct extcon_dev *edev, unsigned int id,
-				bool cable_state);
-/*
- * Synchronize the state and property data for a specific external connector.
- */
-extern int extcon_sync(struct extcon_dev *edev, unsigned int id);
+				bool state);
 
 /*
- * get/set_property access the property value of each external connector.
- * They are used to access the property of each cable based on the property id.
+ * Following APIs get/set the property of each external connector.
+ * The 'id' argument indicates the defined external connector
+ * and the 'prop' indicates the extcon property.
+ *
+ * And extcon_get/set_property_capability() set the capability of the property
+ * for each external connector. They are used to set the capability of the
+ * property of each external connector based on the id and property.
  */
 extern int extcon_get_property(struct extcon_dev *edev, unsigned int id,
 				unsigned int prop,
@@ -224,19 +221,15 @@ extern int extcon_set_property(struct extcon_dev *edev, unsigned int id,
 extern int extcon_set_property_sync(struct extcon_dev *edev, unsigned int id,
 				unsigned int prop,
 				union extcon_property_value prop_val);
-
-/*
- * get/set_property_capability set the capability of the property for each
- * external connector. They are used to set the capability of the property
- * of each external connector based on the id and property.
- */
 extern int extcon_get_property_capability(struct extcon_dev *edev,
 				unsigned int id, unsigned int prop);
 extern int extcon_set_property_capability(struct extcon_dev *edev,
 				unsigned int id, unsigned int prop);
 
 /*
- * Following APIs are to monitor the status change of the external connectors.
+ * Following APIs register the notifier block in order to detect
+ * the change of both state and property value for each external connector.
+ *
  * extcon_register_notifier(*edev, id, *nb) : Register a notifier block
  *			for specific external connector of the extcon.
  * extcon_register_notifier_all(*edev, *nb) : Register a notifier block
@@ -265,16 +258,15 @@ extern void devm_extcon_unregister_notifier_all(struct device *dev,
 				struct notifier_block *nb);
 
 /*
- * Following API get the extcon device from devicetree.
- * This function use phandle of devicetree to get extcon device directly.
+ * Following APIs get the extcon_dev from devicetree or by through extcon name.
  */
+extern struct extcon_dev *extcon_get_extcon_dev(const char *extcon_name);
 extern struct extcon_dev *extcon_get_edev_by_phandle(struct device *dev,
 						     int index);
 
-/* Following API to get information of extcon device */
+/* Following API get the name of extcon device. */
 extern const char *extcon_get_edev_name(struct extcon_dev *edev);
 
-
 #else /* CONFIG_EXTCON */
 static inline int extcon_dev_register(struct extcon_dev *edev)
 {
@@ -314,13 +306,13 @@ static inline int extcon_get_state(struct extcon_dev *edev, unsigned int id)
 }
 
 static inline int extcon_set_state(struct extcon_dev *edev, unsigned int id,
-				bool cable_state)
+				bool state)
 {
 	return 0;
 }
 
 static inline int extcon_set_state_sync(struct extcon_dev *edev, unsigned int id,
-				bool cable_state)
+				bool state)
 {
 	return 0;
 }
@@ -362,11 +354,6 @@ static inline int extcon_set_property_capability(struct extcon_dev *edev,
 	return 0;
 }
 
-static inline struct extcon_dev *extcon_get_extcon_dev(const char *extcon_name)
-{
-	return NULL;
-}
-
 static inline int extcon_register_notifier(struct extcon_dev *edev,
 					unsigned int id,
 					struct notifier_block *nb)
@@ -392,6 +379,11 @@ static inline  void devm_extcon_unregister_notifier(struct device *dev,
 				struct extcon_dev *edev, unsigned int id,
 				struct notifier_block *nb) { }
 
+static inline struct extcon_dev *extcon_get_extcon_dev(const char *extcon_name)
+{
+	return NULL;
+}
+
 static inline struct extcon_dev *extcon_get_edev_by_phandle(struct device *dev,
 							    int index)
 {