diff options
| -rw-r--r-- | drivers/extcon/extcon_class.c | 66 | ||||
| -rw-r--r-- | include/linux/extcon.h | 38 |
2 files changed, 104 insertions, 0 deletions
diff --git a/drivers/extcon/extcon_class.c b/drivers/extcon/extcon_class.c index 3c46368c279a..83a088f1edc4 100644 --- a/drivers/extcon/extcon_class.c +++ b/drivers/extcon/extcon_class.c @@ -36,6 +36,9 @@ struct class *extcon_class; static struct class_compat *switch_class; #endif /* CONFIG_ANDROID && !defined(CONFIG_ANDROID_SWITCH) */ +static LIST_HEAD(extcon_dev_list); +static DEFINE_MUTEX(extcon_dev_list_lock); + static ssize_t state_show(struct device *dev, struct device_attribute *attr, char *buf) { @@ -75,6 +78,9 @@ static ssize_t name_show(struct device *dev, struct device_attribute *attr, * the name of extcon device (envp[0]) and the state output (envp[1]). * Tizen uses this format for extcon device to get events from ports. * Android uses this format as well. + * + * Note that notifier provides the which bits are changes in the state + * variable with "val" to the callback. */ void extcon_set_state(struct extcon_dev *edev, u32 state) { @@ -84,10 +90,14 @@ void extcon_set_state(struct extcon_dev *edev, u32 state) char *envp[3]; int env_offset = 0; int length; + u32 old_state = edev->state; if (edev->state != state) { edev->state = state; + raw_notifier_call_chain(&edev->nh, old_state ^ edev->state, + edev); + prop_buf = (char *)get_zeroed_page(GFP_KERNEL); if (prop_buf) { length = name_show(edev->dev, NULL, prop_buf); @@ -117,6 +127,51 @@ void extcon_set_state(struct extcon_dev *edev, u32 state) } EXPORT_SYMBOL_GPL(extcon_set_state); +/** + * extcon_get_extcon_dev() - Get the extcon device instance from the name + * @extcon_name: The extcon name provided with extcon_dev_register() + */ +struct extcon_dev *extcon_get_extcon_dev(const char *extcon_name) +{ + struct extcon_dev *sd; + + mutex_lock(&extcon_dev_list_lock); + list_for_each_entry(sd, &extcon_dev_list, entry) { + if (!strcmp(sd->name, extcon_name)) + goto out; + } + sd = NULL; +out: + mutex_unlock(&extcon_dev_list_lock); + return sd; +} +EXPORT_SYMBOL_GPL(extcon_get_extcon_dev); + +/** + * extcon_register_notifier() - Register a notifee to get notified by + * any attach status changes from the extcon. + * @edev: the extcon device. + * @nb: a notifier block to be registered. + */ +int extcon_register_notifier(struct extcon_dev *edev, + struct notifier_block *nb) +{ + return raw_notifier_chain_register(&edev->nh, nb); +} +EXPORT_SYMBOL_GPL(extcon_register_notifier); + +/** + * extcon_unregister_notifier() - Unregister a notifee from the extcon device. + * @edev: the extcon device. + * @nb: a registered notifier block to be unregistered. + */ +int extcon_unregister_notifier(struct extcon_dev *edev, + struct notifier_block *nb) +{ + return raw_notifier_chain_unregister(&edev->nh, nb); +} +EXPORT_SYMBOL_GPL(extcon_unregister_notifier); + static struct device_attribute extcon_attrs[] = { __ATTR_RO(state), __ATTR_RO(name), @@ -142,6 +197,10 @@ static int create_extcon_class(void) static void extcon_cleanup(struct extcon_dev *edev, bool skip) { + mutex_lock(&extcon_dev_list_lock); + list_del(&edev->entry); + mutex_unlock(&extcon_dev_list_lock); + if (!skip && get_device(edev->dev)) { device_unregister(edev->dev); put_device(edev->dev); @@ -194,8 +253,15 @@ int extcon_dev_register(struct extcon_dev *edev, struct device *dev) dev); #endif /* CONFIG_ANDROID && !defined(CONFIG_ANDROID_SWITCH) */ + RAW_INIT_NOTIFIER_HEAD(&edev->nh); + dev_set_drvdata(edev->dev, edev); edev->state = 0; + + mutex_lock(&extcon_dev_list_lock); + list_add(&edev->entry, &extcon_dev_list); + mutex_unlock(&extcon_dev_list_lock); + return 0; err_dev: diff --git a/include/linux/extcon.h b/include/linux/extcon.h index 9cb3aaaf67f5..c9c9afe12b47 100644 --- a/include/linux/extcon.h +++ b/include/linux/extcon.h @@ -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__ */ |