Extcon: support notification based on the state changes.
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
Greg Kroah-Hartman
parent
be48308a24
commit
74c5d09bd5
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@ -36,6 +36,9 @@ struct class *extcon_class;
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static struct class_compat *switch_class;
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#endif /* CONFIG_ANDROID && !defined(CONFIG_ANDROID_SWITCH) */
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static LIST_HEAD(extcon_dev_list);
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static DEFINE_MUTEX(extcon_dev_list_lock);
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static ssize_t state_show(struct device *dev, struct device_attribute *attr,
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char *buf)
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{
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@ -75,6 +78,9 @@ static ssize_t name_show(struct device *dev, struct device_attribute *attr,
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* the name of extcon device (envp[0]) and the state output (envp[1]).
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* Tizen uses this format for extcon device to get events from ports.
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* Android uses this format as well.
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*
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* Note that notifier provides the which bits are changes in the state
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* variable with "val" to the callback.
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*/
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void extcon_set_state(struct extcon_dev *edev, u32 state)
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{
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@ -84,10 +90,14 @@ void extcon_set_state(struct extcon_dev *edev, u32 state)
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char *envp[3];
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int env_offset = 0;
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int length;
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u32 old_state = edev->state;
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if (edev->state != state) {
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edev->state = state;
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raw_notifier_call_chain(&edev->nh, old_state ^ edev->state,
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edev);
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prop_buf = (char *)get_zeroed_page(GFP_KERNEL);
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if (prop_buf) {
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length = name_show(edev->dev, NULL, prop_buf);
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@ -117,6 +127,51 @@ void extcon_set_state(struct extcon_dev *edev, u32 state)
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}
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EXPORT_SYMBOL_GPL(extcon_set_state);
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/**
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* extcon_get_extcon_dev() - Get the extcon device instance from the name
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* @extcon_name: The extcon name provided with extcon_dev_register()
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*/
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struct extcon_dev *extcon_get_extcon_dev(const char *extcon_name)
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{
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struct extcon_dev *sd;
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mutex_lock(&extcon_dev_list_lock);
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list_for_each_entry(sd, &extcon_dev_list, entry) {
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if (!strcmp(sd->name, extcon_name))
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goto out;
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}
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sd = NULL;
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out:
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mutex_unlock(&extcon_dev_list_lock);
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return sd;
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}
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EXPORT_SYMBOL_GPL(extcon_get_extcon_dev);
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/**
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* extcon_register_notifier() - Register a notifee to get notified by
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* any attach status changes from the extcon.
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* @edev: the extcon device.
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* @nb: a notifier block to be registered.
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*/
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int extcon_register_notifier(struct extcon_dev *edev,
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struct notifier_block *nb)
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{
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return raw_notifier_chain_register(&edev->nh, nb);
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}
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EXPORT_SYMBOL_GPL(extcon_register_notifier);
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/**
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* extcon_unregister_notifier() - Unregister a notifee from the extcon device.
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* @edev: the extcon device.
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* @nb: a registered notifier block to be unregistered.
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*/
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int extcon_unregister_notifier(struct extcon_dev *edev,
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struct notifier_block *nb)
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{
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return raw_notifier_chain_unregister(&edev->nh, nb);
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}
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EXPORT_SYMBOL_GPL(extcon_unregister_notifier);
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static struct device_attribute extcon_attrs[] = {
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__ATTR_RO(state),
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__ATTR_RO(name),
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@ -142,6 +197,10 @@ static int create_extcon_class(void)
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static void extcon_cleanup(struct extcon_dev *edev, bool skip)
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{
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mutex_lock(&extcon_dev_list_lock);
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list_del(&edev->entry);
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mutex_unlock(&extcon_dev_list_lock);
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if (!skip && get_device(edev->dev)) {
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device_unregister(edev->dev);
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put_device(edev->dev);
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@ -194,8 +253,15 @@ int extcon_dev_register(struct extcon_dev *edev, struct device *dev)
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dev);
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#endif /* CONFIG_ANDROID && !defined(CONFIG_ANDROID_SWITCH) */
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RAW_INIT_NOTIFIER_HEAD(&edev->nh);
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dev_set_drvdata(edev->dev, edev);
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edev->state = 0;
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mutex_lock(&extcon_dev_list_lock);
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list_add(&edev->entry, &extcon_dev_list);
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mutex_unlock(&extcon_dev_list_lock);
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return 0;
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err_dev:
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@ -23,6 +23,7 @@
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#ifndef __LINUX_EXTCON_H__
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#define __LINUX_EXTCON_H__
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#include <linux/notifier.h>
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/**
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* struct extcon_dev - An extcon device represents one external connector.
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* @name The name of this extcon device. Parent device name is used
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@ -34,6 +35,9 @@
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* @dev Device of this extcon. Do not provide at register-time.
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* @state Attach/detach state of this extcon. Do not provide at
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* register-time
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* @nh Notifier for the state change events from this extcon
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* @entry To support list of extcon devices so that uses can search
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* for extcon devices based on the extcon name.
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*
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* In most cases, users only need to provide "User initializing data" of
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* this struct when registering an extcon. In some exceptional cases,
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@ -51,11 +55,19 @@ struct extcon_dev {
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/* --- Internal data. Please do not set. --- */
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struct device *dev;
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u32 state;
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struct raw_notifier_head nh;
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struct list_head entry;
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};
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#if IS_ENABLED(CONFIG_EXTCON)
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/*
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* Following APIs are for notifiers or configurations.
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* Notifiers are the external port and connection devices.
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*/
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extern int extcon_dev_register(struct extcon_dev *edev, struct device *dev);
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extern void extcon_dev_unregister(struct extcon_dev *edev);
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extern struct extcon_dev *extcon_get_extcon_dev(const char *extcon_name);
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static inline u32 extcon_get_state(struct extcon_dev *edev)
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{
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@ -63,6 +75,15 @@ static inline u32 extcon_get_state(struct extcon_dev *edev)
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}
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extern void extcon_set_state(struct extcon_dev *edev, u32 state);
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/*
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* Following APIs are to monitor every action of a notifier.
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* Registerer gets notified for every external port of a connection device.
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*/
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extern int extcon_register_notifier(struct extcon_dev *edev,
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struct notifier_block *nb);
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extern int extcon_unregister_notifier(struct extcon_dev *edev,
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struct notifier_block *nb);
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#else /* CONFIG_EXTCON */
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static inline int extcon_dev_register(struct extcon_dev *edev,
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struct device *dev)
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@ -78,5 +99,22 @@ static inline u32 extcon_get_state(struct extcon_dev *edev)
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}
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static inline void extcon_set_state(struct extcon_dev *edev, u32 state) { }
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static inline struct extcon_dev *extcon_get_extcon_dev(const char *extcon_name)
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{
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return NULL;
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}
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static inline int extcon_register_notifier(struct extcon_dev *edev,
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struct notifier_block *nb)
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{
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return 0;
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}
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static inline int extcon_unregister_notifier(struct extcon_dev *edev,
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struct notifier_block *nb)
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{
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return 0;
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}
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#endif /* CONFIG_EXTCON */
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#endif /* __LINUX_EXTCON_H__ */
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