This reverts commit 5461f3fd74a89757f95f351eb0bc26aafc2a2e91. The backlight notifier support is needed in order to add backlight control support into DRM connectors.
Signed-off-by: Mario Limonciello (AMD) <[email protected]> --- drivers/video/backlight/backlight.c | 42 +++++++++++++++++++++++++++++ include/linux/backlight.h | 20 ++++++++++++++ 2 files changed, 62 insertions(+) diff --git a/drivers/video/backlight/backlight.c b/drivers/video/backlight/backlight.c index a22d0bbb6e63..ff2c2084c73a 100644 --- a/drivers/video/backlight/backlight.c +++ b/drivers/video/backlight/backlight.c @@ -65,6 +65,7 @@ static struct list_head backlight_dev_list; static struct mutex backlight_dev_list_mutex; +static struct blocking_notifier_head backlight_notifier; static const char *const backlight_types[] = { [BACKLIGHT_RAW] = "raw", @@ -415,6 +416,9 @@ struct backlight_device *backlight_device_register(const char *name, list_add(&new_bd->entry, &backlight_dev_list); mutex_unlock(&backlight_dev_list_mutex); + blocking_notifier_call_chain(&backlight_notifier, + BACKLIGHT_REGISTERED, new_bd); + return new_bd; } EXPORT_SYMBOL(backlight_device_register); @@ -484,6 +488,9 @@ void backlight_device_unregister(struct backlight_device *bd) mutex_unlock(&pmac_backlight_mutex); #endif + blocking_notifier_call_chain(&backlight_notifier, + BACKLIGHT_UNREGISTERED, bd); + mutex_lock(&bd->ops_lock); bd->ops = NULL; mutex_unlock(&bd->ops_lock); @@ -507,6 +514,40 @@ static int devm_backlight_device_match(struct device *dev, void *res, return *r == data; } +/** + * backlight_register_notifier - get notified of backlight (un)registration + * @nb: notifier block with the notifier to call on backlight (un)registration + * + * Register a notifier to get notified when backlight devices get registered + * or unregistered. + * + * RETURNS: + * + * 0 on success, otherwise a negative error code + */ +int backlight_register_notifier(struct notifier_block *nb) +{ + return blocking_notifier_chain_register(&backlight_notifier, nb); +} +EXPORT_SYMBOL(backlight_register_notifier); + +/** + * backlight_unregister_notifier - unregister a backlight notifier + * @nb: notifier block to unregister + * + * Register a notifier to get notified when backlight devices get registered + * or unregistered. + * + * RETURNS: + * + * 0 on success, otherwise a negative error code + */ +int backlight_unregister_notifier(struct notifier_block *nb) +{ + return blocking_notifier_chain_unregister(&backlight_notifier, nb); +} +EXPORT_SYMBOL(backlight_unregister_notifier); + /** * devm_backlight_device_register - register a new backlight device * @dev: the device to register @@ -674,6 +715,7 @@ static int __init backlight_class_init(void) INIT_LIST_HEAD(&backlight_dev_list); mutex_init(&backlight_dev_list_mutex); + BLOCKING_INIT_NOTIFIER_HEAD(&backlight_notifier); return 0; } diff --git a/include/linux/backlight.h b/include/linux/backlight.h index f29a9ef1052e..d905173c7f73 100644 --- a/include/linux/backlight.h +++ b/include/linux/backlight.h @@ -64,6 +64,24 @@ enum backlight_type { BACKLIGHT_TYPE_MAX, }; +/** + * enum backlight_notification - the type of notification + * + * The notifications that is used for notification sent to the receiver + * that registered notifications using backlight_register_notifier(). + */ +enum backlight_notification { + /** + * @BACKLIGHT_REGISTERED: The backlight device is registered. + */ + BACKLIGHT_REGISTERED, + + /** + * @BACKLIGHT_UNREGISTERED: The backlight revice is unregistered. + */ + BACKLIGHT_UNREGISTERED, +}; + /** enum backlight_scale - the type of scale used for brightness values * * The type of scale used for brightness values. @@ -388,6 +406,8 @@ void devm_backlight_device_unregister(struct device *dev, struct backlight_device *bd); void backlight_force_update(struct backlight_device *bd, enum backlight_update_reason reason); +int backlight_register_notifier(struct notifier_block *nb); +int backlight_unregister_notifier(struct notifier_block *nb); struct backlight_device *backlight_device_get_by_name(const char *name); struct backlight_device *backlight_device_get_by_type(enum backlight_type type); int backlight_device_set_brightness(struct backlight_device *bd, -- 2.54.0
