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Extcon: support notification based on the state changes.

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State changes of extcon devices have been notified via kobjet_uevent.
This patch adds notifier interfaces in order to allow device drivers to
get notified easily. Along with notifier interface,
extcon_get_extcon_dev() function is added so that device drivers may
discover a extcon_dev easily.

Signed-off-by: Donggeun Kim <dg77.kim@samsung.com>
Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

--
Changes from RFC
- Renamed switch to extcon
- Bugfix: extcon_dev_unregister()
- Bugfix: "edev->dev" is "internal" data.
- Added kerneldoc comments.
- Reworded comments.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Donggeun Kim
2012-04-20 14:16:24 +09:00
committed by Greg Kroah-Hartman
parent be48308a24
commit 74c5d09bd5
2 changed files with 104 additions and 0 deletions
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38
include/linux/extcon.h
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@@ -23,6 +23,7 @@
#ifndef __LINUX_EXTCON_H__
#define __LINUX_EXTCON_H__
#include <linux/notifier.h>
/**
* struct extcon_dev - An extcon device represents one external connector.
* @name The name of this extcon device. Parent device name is used
@@ -34,6 +35,9 @@
* @dev Device of this extcon. Do not provide at register-time.
* @state Attach/detach state of this extcon. Do not provide at
* register-time
* @nh Notifier for the state change events from this extcon
* @entry To support list of extcon devices so that uses can search
* for extcon devices based on the extcon name.
*
* In most cases, users only need to provide "User initializing data" of
* this struct when registering an extcon. In some exceptional cases,
@@ -51,11 +55,19 @@ struct extcon_dev {
/* --- Internal data. Please do not set. --- */
struct device *dev;
u32 state;
struct raw_notifier_head nh;
struct list_head entry;
};
#if IS_ENABLED(CONFIG_EXTCON)
/*
* Following APIs are for notifiers or configurations.
* Notifiers are the external port and connection devices.
*/
extern int extcon_dev_register(struct extcon_dev *edev, struct device *dev);
extern void extcon_dev_unregister(struct extcon_dev *edev);
extern struct extcon_dev *extcon_get_extcon_dev(const char *extcon_name);
static inline u32 extcon_get_state(struct extcon_dev *edev)
{
@@ -63,6 +75,15 @@ static inline u32 extcon_get_state(struct extcon_dev *edev)
}
extern void extcon_set_state(struct extcon_dev *edev, u32 state);
/*
* Following APIs are to monitor every action of a notifier.
* Registerer gets notified for every external port of a connection device.
*/
extern int extcon_register_notifier(struct extcon_dev *edev,
struct notifier_block *nb);
extern int extcon_unregister_notifier(struct extcon_dev *edev,
struct notifier_block *nb);
#else /* CONFIG_EXTCON */
static inline int extcon_dev_register(struct extcon_dev *edev,
struct device *dev)
@@ -78,5 +99,22 @@ static inline u32 extcon_get_state(struct extcon_dev *edev)
}
static inline void extcon_set_state(struct extcon_dev *edev, u32 state) { }
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,
struct notifier_block *nb)
{
return 0;
}
static inline int extcon_unregister_notifier(struct extcon_dev *edev,
struct notifier_block *nb)
{
return 0;
}
#endif /* CONFIG_EXTCON */
#endif /* __LINUX_EXTCON_H__ */