Messages in this thread Patch in this message | | | From | MyungJoo Ham <> | Subject | [PATCH v2 3/3] Extcon: support multiple states at a device. | Date | Wed, 14 Dec 2011 19:28:28 +0900 |
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One switch device (e.g., MUIC(MAX8997, MAX77686, ...), and some 30-pin devices) may have multiple cables attached. For example, one 30-pin port may inhabit a USB cable, an HDMI cable, and a mic. Thus, one switch device requires multiple state bits each representing a type of cable.
For such purpose, we use the 32bit state variable; thus, up to 32 different type of cables may be defined for a switch device. The list of possible cables is defined by the array of cable names in the switch_dev struct given to the class.
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>
-- Changes from RFC - Switch is renamed to extcon - Added kerneldoc comments - Added APIs to support "standard" cable names - Added helper APIs to support notifier block registration with cable name. - Regrouped function list in the header file. --- drivers/extcon/extcon_class.c | 255 +++++++++++++++++++++++++++++++++++++++-- include/linux/extcon.h | 149 ++++++++++++++++++++++++ 2 files changed, 395 insertions(+), 9 deletions(-)
diff --git a/drivers/extcon/extcon_class.c b/drivers/extcon/extcon_class.c index 0223897..72f6e3e 100644 --- a/drivers/extcon/extcon_class.c +++ b/drivers/extcon/extcon_class.c @@ -30,6 +30,25 @@ #include <linux/err.h> #include <linux/extcon.h> +const char *extcon_cable_name[] = { + [EXTCON_USB] = "USB", + [EXTCON_USB_HOST] = "USB-Host", + [EXTCON_TA] = "TA", + [EXTCON_FAST_CHARGER] = "Fast-charger", + [EXTCON_SLOW_CHARGER] = "Slow-charger", + [EXTCON_CHARGE_DOWNSTREAM] = "Charge-downstream", + [EXTCON_HDMI] = "HDMI", + [EXTCON_MHL] = "MHL", + [EXTCON_DVI] = "DVI", + [EXTCON_VGA] = "VGA", + [EXTCON_DOCK] = "Dock", + [EXTCON_AUDIO_IN] = "Audio-in", + [EXTCON_AUDIO_OUT] = "Audio-out", + [EXTCON_VIDEO_IN] = "Video-in", + [EXTCON_VIDEO_OUT] = "Video-out", + + NULL, +}; struct class *extcon_class; static atomic_t device_count; @@ -39,6 +58,7 @@ static DEFINE_MUTEX(extcon_dev_list_lock); static ssize_t state_show(struct device *dev, struct device_attribute *attr, char *buf) { + int i, count = 0; struct extcon_dev *edev = (struct extcon_dev *) dev_get_drvdata(dev); @@ -49,7 +69,22 @@ static ssize_t state_show(struct device *dev, struct device_attribute *attr, return ret; /* Use default if failed */ } - return sprintf(buf, "%u\n", edev->state); + + if (edev->max_supported == 0) + return sprintf(buf, "%u\n", edev->state); + + for (i = 0; i < SUPPORTED_CABLE_MAX; i++) { + if (!edev->supported_cable[i]) + break; + if (i > 0) + count += sprintf(buf + count, ", "); + count += sprintf(buf + count, "%s %d", + edev->supported_cable[i], + !!(edev->state & (1 << i))); + } + count += sprintf(buf + count, "\n"); + + return count; } static ssize_t name_show(struct device *dev, struct device_attribute *attr, @@ -70,14 +105,16 @@ static DEVICE_ATTR(state, S_IRUGO, state_show, NULL); static DEVICE_ATTR(name, S_IRUGO, name_show, NULL); /** - * extcon_set_state() - Set the cable attach states of the extcon device. + * extcon_update_state() - Update the cable attach states of the extcon device + * only for the masked bits. * @edev: the extcon device + * @mask: the bit mask to designate updated bits. * @state: new cable attach status for @edev * - * Note that notifier provides the which bits are changes in the state - * variable with "val" to the callback. + * Note that the notifier provides which bits are changed in the state + * variable with the val parameter (second) to the callback. */ -void extcon_set_state(struct extcon_dev *edev, u32 state) +void extcon_update_state(struct extcon_dev *edev, u32 mask, u32 state) { char name_buf[120]; char state_buf[120]; @@ -85,10 +122,15 @@ void extcon_set_state(struct extcon_dev *edev, u32 state) char *envp[3]; int env_offset = 0; int length; - u32 old_state = edev->state; + unsigned long flags; + + spin_lock_irqsave(&edev->lock, flags); - if (edev->state != state) { - edev->state = state; + if (edev->state != ((edev->state & ~mask) | (state & mask))) { + u32 old_state = edev->state; + + edev->state &= ~mask; + edev->state |= state & mask; raw_notifier_call_chain(&edev->nh, old_state ^ edev->state, edev); @@ -112,17 +154,132 @@ void extcon_set_state(struct extcon_dev *edev, u32 state) envp[env_offset++] = state_buf; } envp[env_offset] = NULL; + /* Unlock early before uevent */ + spin_unlock_irqrestore(&edev->lock, flags); + kobject_uevent_env(&edev->dev->kobj, KOBJ_CHANGE, envp); free_page((unsigned long)prop_buf); } else { + /* Unlock early before uevent */ + spin_unlock_irqrestore(&edev->lock, flags); + printk(KERN_ERR "out of memory in extcon_set_state\n"); kobject_uevent(&edev->dev->kobj, KOBJ_CHANGE); } + } else { + /* No changes */ + spin_unlock_irqrestore(&edev->lock, flags); } } +EXPORT_SYMBOL_GPL(extcon_update_state); + +/** + * extcon_set_state() - Set the cable attach states of the extcon device. + * @edev: the extcon device + * @state: new cable attach status for @edev + * + * Note that notifier provides which bits are changed in the state + * variable with the val parameter (second) to the callback. + */ +void extcon_set_state(struct extcon_dev *edev, u32 state) +{ + extcon_update_state(edev, 0xffffffff, state); +} EXPORT_SYMBOL_GPL(extcon_set_state); /** + * extcon_find_cable_index() - Get the cable index based on the cable name. + * @edev: the extcon device that has the cable. + * @cable_name: cable name to be searched. + * + * Note that accessing a cable state based on cable_index is faster than + * cable_name because using cable_name induces a loop with strncmp(). + * Thus, when get/set_cable_state is repeatedly used, using cable_index + * is recommended. + */ +int extcon_find_cable_index(struct extcon_dev *edev, const char *cable_name) +{ + int i; + + if (edev->supported_cable) { + for (i = 0; edev->supported_cable[i]; i++) { + if (!strncmp(edev->supported_cable[i], + cable_name, CABLE_NAME_MAX)) + return i; + } + } + + return -EINVAL; +} +EXPORT_SYMBOL_GPL(extcon_find_cable_index); + +/** + * extcon_get_cable_state_() - Get the status of a specific cable. + * @edev: the extcon device that has the cable. + * @index: cable index that can be retrieved by extcon_find_cable_index(). + */ +int extcon_get_cable_state_(struct extcon_dev *edev, int index) +{ + if (index < 0 || (edev->max_supported && edev->max_supported <= index)) + return -EINVAL; + + return !!(edev->state & (1 << index)); +} +EXPORT_SYMBOL_GPL(extcon_get_cable_state_); + +/** + * extcon_get_cable_state() - Get the status of a specific cable. + * @edev: the extcon device that has the cable. + * @cable_name: cable name. + * + * Note that this is slower than extcon_get_cable_state_. + */ +int extcon_get_cable_state(struct extcon_dev *edev, const char *cable_name) +{ + return extcon_get_cable_state_(edev, extcon_find_cable_index + (edev, cable_name)); +} +EXPORT_SYMBOL_GPL(extcon_get_cable_state); + +/** + * extcon_get_cable_state_() - Set the status of a specific cable. + * @edev: the extcon device that has the cable. + * @index: cable index that can be retrieved by extcon_find_cable_index(). + * @cable_state: the new cable status. The default semantics is + * true: attached / false: detached. + */ +int extcon_set_cable_state_(struct extcon_dev *edev, + int index, bool cable_state) +{ + u32 state; + + if (index < 0 || (edev->max_supported && edev->max_supported <= index)) + return -EINVAL; + + state = cable_state ? (1 << index) : 0; + extcon_update_state(edev, 1 << index, state); + return 0; +} +EXPORT_SYMBOL_GPL(extcon_set_cable_state_); + +/** + * extcon_get_cable_state() - Set the status of a specific cable. + * @edev: the extcon device that has the cable. + * @cable_name: cable name. + * @cable_state: the new cable status. The default semantics is + * true: attached / false: detached. + * + * Note that this is slower than extcon_set_cable_state_. + */ +int extcon_set_cable_state(struct extcon_dev *edev, + const char *cable_name, bool cable_state) +{ + return extcon_set_cable_state_(edev, extcon_find_cable_index + (edev, cable_name), cable_state); +} +EXPORT_SYMBOL_GPL(extcon_set_cable_state); + +/** * extcon_get_extcon_dev() - Get the extcon device instance from the name * @extcon_name: The extcon name provided with extcon_dev_register() */ @@ -142,6 +299,71 @@ out: } EXPORT_SYMBOL_GPL(extcon_get_extcon_dev); +static int _call_per_cable(struct notifier_block *nb, unsigned long val, + void *ptr) +{ + struct extcon_specific_cable_nb *obj = container_of(nb, + struct extcon_specific_cable_nb, internal_nb); + + if (val & (1 << obj->cable_index)) + return obj->user_nb->notifier_call(nb, val, ptr); + + return NOTIFY_OK; +} + +/** + * extcon_register_interest() - Register a notifier for a state change of a + * specific cable, not a entier set of cables of a + * extcon device. + * @obj: an empty extcon_specific_cable_nb object to be returned. + * @extcon_name: the name of extcon device. + * @cable_name: the target cable name. + * @nb: the notifier block to get notified. + * + * Provide an empty extcon_specific_cable_nb. extcon_register_interest() sets + * the struct for you. + * + * extcon_register_interest is a helper function for those who want to get + * notification for a single specific cable's status change. If a user wants + * to get notification for any changes of all cables of a extcon device, + * he/she should use the general extcon_register_notifier(). + */ +int extcon_register_interest(struct extcon_specific_cable_nb *obj, + const char *extcon_name, const char *cable_name, + struct notifier_block *nb) +{ + if (!obj || !extcon_name || !cable_name || !nb) + return -EINVAL; + + obj->edev = extcon_get_extcon_dev(extcon_name); + if (!obj->edev) + return -ENODEV; + + obj->cable_index = extcon_find_cable_index(obj->edev, cable_name); + if (obj->cable_index < 0) + return -ENODEV; + + obj->user_nb = nb; + + obj->internal_nb.notifier_call = _call_per_cable; + + return raw_notifier_chain_register(&obj->edev->nh, &obj->internal_nb); +} + +/** + * extcon_unregister_interest() - Unregister the notifier registered by + * extcon_register_interest(). + * @obj: the extcon_specific_cable_nb object returned by + * extcon_register_interest(). + */ +int extcon_unregister_interest(struct extcon_specific_cable_nb *obj) +{ + if (!obj) + return -EINVAL; + + return raw_notifier_chain_unregister(&obj->edev->nh, &obj->internal_nb); +} + /** * extcon_register_notifier() - Register a notifee to get notified by * any attach status changes from the extcon. @@ -190,7 +412,7 @@ static int create_extcon_class(void) */ int extcon_dev_register(struct extcon_dev *edev) { - int ret; + int ret, index = 0; if (!extcon_class) { ret = create_extcon_class(); @@ -198,6 +420,21 @@ int extcon_dev_register(struct extcon_dev *edev) return ret; } + if (edev->supported_cable) { + /* Get size of array */ + for (index = 0; edev->supported_cable[index]; index++) + ; + edev->max_supported = index; + } else { + edev->max_supported = 0; + } + + if (index > SUPPORTED_CABLE_MAX) { + dev_err(edev->dev, "extcon: maximum number of supported cables exceeded.\n"); + return -EINVAL; + } + + spin_lock_init(&edev->lock); edev->index = atomic_inc_return(&device_count); edev->dev = device_create(extcon_class, NULL, MKDEV(0, edev->index), NULL, edev->name); diff --git a/include/linux/extcon.h b/include/linux/extcon.h index 64b57a2..77be7b1 100644 --- a/include/linux/extcon.h +++ b/include/linux/extcon.h @@ -24,10 +24,54 @@ #define __LINUX_EXTCON_H__ #include <linux/notifier.h> + +#define SUPPORTED_CABLE_MAX 32 +#define CABLE_NAME_MAX 30 + +/* + * The standard cable name is to help support general notifier + * and notifee device drivers to share the common names. + * Please use standard cable names unless your notifier device has + * a very unique and abnormal cable or + * the cable type is supposed to be used with only one unique + * pair of notifier/notifee devices. + * + * Please add any other "standard" cables used with extcon dev. + * + * You may add a dot and number to specify version or specification + * of the specific cable if it is required. (e.g., "Fast-charger.18" + * and "Fast-charger.10" for 1.8A and 1.0A chargers) + * However, the notifee and notifier should be able to handle such + * string and if the notifee can negotiate the protocol or idenify, + * you don't need such convention. This convention is helpful when + * notifier can distinguish but notifiee cannot. + */ +enum extcon_cable_name { + EXTCON_USB = 0, + EXTCON_USB_HOST, + EXTCON_TA, /* Travel Adaptor */ + EXTCON_FAST_CHARGER, + EXTCON_SLOW_CHARGER, + EXTCON_CHARGE_DOWNSTREAM, /* Charging an external device */ + EXTCON_HDMI, + EXTCON_MHL, + EXTCON_DVI, + EXTCON_VGA, + EXTCON_DOCK, + EXTCON_AUDIO_IN, + EXTCON_AUDIO_OUT, + EXTCON_VIDEO_IN, + EXTCON_VIDEO_OUT, +}; +extern const char *extcon_cable_name[]; + /** * struct extcon_dev - An extcon device represents one external connector. * @name The name of this extcon device. Please provide one when * registering an extcon_dev. + * @supported_cable Array of supported cable name ending with NULL. + * If supported_cable is NULL, cable name related APIs + * are disabled. * @print_name An optional callback to override the method to print the * name of the extcon device. * @print_state An optional callback to override the method to print the @@ -39,6 +83,8 @@ * @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. + * @lock + * @max_supported Internal value to store the number of cables. * * In most cases, users only need to provide "User initializing data" of * this struct when registering an extcon. In some exceptional cases, @@ -48,6 +94,7 @@ struct extcon_dev { /* --- User initializing data --- */ const char *name; + const char **supported_cable; /* --- Optional callbacks to override class functions --- */ ssize_t (*print_name)(struct extcon_dev *edev, char *buf); @@ -59,6 +106,8 @@ struct extcon_dev { int index; struct raw_notifier_head nh; struct list_head entry; + spinlock_t lock; /* could be called by irq handler */ + int max_supported; }; /** @@ -79,6 +128,21 @@ struct gpio_extcon_platform_data { const char *state_off; }; +/** + * struct extcon_specific_cable_nb - An internal data for + * extcon_register_interest(). + * @internal_nb a notifier block bridging extcon notifier and cable notifier. + * @user_nb user provided notifier block for events from a specific cable. + * @cable_index the target cable. + * @edev the target extcon device. + */ +struct extcon_specific_cable_nb { + struct notifier_block internal_nb; + struct notifier_block *user_nb; + int cable_index; + struct extcon_dev *edev; +}; + #ifdef CONFIG_EXTCON /* @@ -90,16 +154,54 @@ extern int extcon_dev_register(struct extcon_dev *edev); extern void extcon_dev_unregister(struct extcon_dev *edev); extern struct extcon_dev *extcon_get_extcon_dev(const char *extcon_name); +/* + * get/set/update_state access the 32b encoded state value, which represents + * states of all possible cables of the multistate port. For example, if one + * calls extcon_set_states(edev, 0x7), it may mean that all the three cables + * are attached to the port. + */ static inline u32 extcon_get_state(struct extcon_dev *edev) { return edev->state; } extern void extcon_set_state(struct extcon_dev *edev, u32 state); +extern void extcon_update_state(struct extcon_dev *edev, u32 mask, u32 state); + +/* + * get/set_cable_state access each bit of the 32b encoded state value. + * They are used to access the status of each cable based on the cable_name + * or cable_index, which is retrived by extcon_find_cable_index + */ +extern int extcon_find_cable_index(struct extcon_dev *sdev, + const char *cable_name); +extern int extcon_get_cable_state_(struct extcon_dev *edev, int cable_index); +extern int extcon_set_cable_state_(struct extcon_dev *edev, int cable_index, + bool cable_state); + +extern int extcon_get_cable_state(struct extcon_dev *edev, + const char *cable_name); +extern int extcon_set_cable_state(struct extcon_dev *edev, + const char *cable_name, bool cable_state); + +/* + * Following APIs are for notifiees (those who want to be notified) + * to register a callback for events from a specific cable of the extcon. + * Notifiees are the connected device drivers wanting to get notified by + * a specific external port of a connection device. + */ +extern int extcon_register_interest(struct extcon_specific_cable_nb *obj, + const char *extcon_name, + const char *cable_name, + struct notifier_block *nb); +extern int extcon_unregister_interest(struct extcon_specific_cable_nb *nb); /* * Following APIs are to monitor every action of a notifier. * Registerer gets notified for every external port of a connection device. + * Probably this could be used to debug an action of notifier; however, + * we do not recommend to use this at normal 'notifiee' device drivers who + * want to be notified by a specific external port of the notifier. */ extern int extcon_register_notifier(struct extcon_dev *edev, struct notifier_block *nb); @@ -119,6 +221,41 @@ static inline u32 extcon_get_state(struct extcon_dev *edev) } static inline void extcon_set_state(struct extcon_dev *edev, u32 state) { } + +static inline void extcon_update_state(struct extcon_dev *edev, u32 mask, + u32 state) +{ } + +static inline int extcon_find_cable_index(struct extcon_dev *edev, + const char *cable_name) +{ + return 0; +} + +static inline int extcon_get_cable_state_(struct extcon_dev *edev, + int cable_index) +{ + return 0; +} + +static inline int extcon_set_cable_state_(struct extcon_dev *edev, + int cable_index, bool cable_state) +{ + return 0; +} + +static inline int extcon_get_cable_state(struct extcon_dev *edev, + const char *cable_name) +{ + return 0; +} + +static inline int extcon_set_cable_state(struct extcon_dev *edev, + const char *cable_name, int state) +{ + return 0; +} + static inline struct extcon_dev *extcon_get_extcon_dev(const char *extcon_name) { return NULL; @@ -136,5 +273,17 @@ static inline int extcon_unregister_notifier(struct extcon_dev *edev, return 0; } +static inline int extcon_register_interest(struct extcon_specific_cable_nb *obj, + const char *extcon_name, + const char *cable_name, + struct notifier_block *nb) +{ + return 0; +} + +static inline int extcon_unregister_interest(struct extcon_specific_cable_nb *) +{ + return 0; +} #endif /* CONFIG_EXTCON */ #endif /* __LINUX_EXTCON_H__ */ -- 1.7.4.1
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