Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758609Ab2BJGkj (ORCPT ); Fri, 10 Feb 2012 01:40:39 -0500 Received: from mailout1.samsung.com ([203.254.224.24]:21835 "EHLO mailout1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758348Ab2BJGke (ORCPT ); Fri, 10 Feb 2012 01:40:34 -0500 X-AuditID: cbfee61b-b7c62ae000000989-ca-4f34bbde16f4 From: MyungJoo Ham To: linux-kernel@vger.kernel.org Cc: NeilBrown , Randy Dunlap , Mike Lockwood , =?UTF-8?q?Arve=20Hj=C3=B8nnevag?= , Kyungmin Park , Donggeun Kim , Greg KH , Arnd Bergmann , Linus Walleij , Dmitry Torokhov , Morten CHRISTIANSEN , Mark Brown , John Stultz , Joerg Roedel , myungjoo.ham@gmail.com Subject: [PATCH v5 2/5] Extcon: support notification based on the state changes. Date: Fri, 10 Feb 2012 15:40:35 +0900 Message-id: <1328856038-21912-3-git-send-email-myungjoo.ham@samsung.com> X-Mailer: git-send-email 1.7.4.1 In-reply-to: <1328856038-21912-1-git-send-email-myungjoo.ham@samsung.com> References: <1327021317-10222-1-git-send-email-myungjoo.ham@samsung.com> <1328856038-21912-1-git-send-email-myungjoo.ham@samsung.com> X-Brightmail-Tracker: AAAAAA== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 7453 Lines: 235 From: Donggeun Kim 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 Signed-off-by: MyungJoo Ham Signed-off-by: Kyungmin Park -- Changes from RFC - Renamed switch to extcon - Bugfix: extcon_dev_unregister() - Bugfix: "edev->dev" is "internal" data. - Added kerneldoc comments. - Reworded comments. --- drivers/extcon/extcon_class.c | 66 +++++++++++++++++++++++++++++++++++++++++ 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 9d29c79..763cf4d 100644 --- a/drivers/extcon/extcon_class.c +++ b/drivers/extcon/extcon_class.c @@ -34,6 +34,9 @@ struct class *extcon_class; struct class *extcon_class_for_android; +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) { @@ -73,6 +76,9 @@ 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) { @@ -82,10 +88,14 @@ 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); @@ -115,6 +125,51 @@ 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), @@ -145,6 +200,10 @@ static int create_extcon_class_for_android(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); @@ -200,8 +259,15 @@ int extcon_dev_register(struct extcon_dev *edev, struct device *dev) goto err_dev; } + 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 da0bbc8..1e47e3b 100644 --- a/include/linux/extcon.h +++ b/include/linux/extcon.h @@ -23,6 +23,7 @@ #ifndef __LINUX_EXTCON_H__ #define __LINUX_EXTCON_H__ +#include /** * struct extcon_dev - An extcon device represents one external connector. * @name The name of this extcon device. Parent device name is used @@ -37,6 +38,9 @@ * @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, @@ -55,6 +59,8 @@ struct extcon_dev { /* --- Internal data. Please do not set. --- */ struct device *dev; u32 state; + struct raw_notifier_head nh; + struct list_head entry; }; /** @@ -76,8 +82,14 @@ struct gpio_extcon_platform_data { }; #ifdef 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) { @@ -85,6 +97,15 @@ 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) @@ -100,5 +121,22 @@ 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__ */ -- 1.7.4.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/