backlight: introduce backlight_device_registered

Introduce a new API for modules to query if a specific type of backlight
device has been registered. This is useful for some backlight device
provider module (e.g. ACPI video) to know if a native control
interface(e.g. the interface created by i915) is available and then do
things accordingly (e.g. avoid registering its own on Win8 systems).

Signed-off-by: Aaron Lu <aaron.lu@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Aaron Lu
2013-10-11 21:27:43 +08:00
committed by Rafael J. Wysocki
parent 068aab7766
commit 5915a3db0c
2 changed files with 35 additions and 0 deletions

View File

@@ -100,6 +100,9 @@ struct backlight_device {
/* The framebuffer notifier block */
struct notifier_block fb_notif;
/* list entry of all registered backlight devices */
struct list_head entry;
struct device dev;
};
@@ -123,6 +126,7 @@ extern void devm_backlight_device_unregister(struct device *dev,
struct backlight_device *bd);
extern void backlight_force_update(struct backlight_device *bd,
enum backlight_update_reason reason);
extern bool backlight_device_registered(enum backlight_type type);
#define to_backlight_device(obj) container_of(obj, struct backlight_device, dev)