@@ -14,21 +14,6 @@
#include <linux/mutex.h>
#include <linux/notifier.h>
-/* Notes on locking:
- *
- * backlight_device->ops_lock is an internal backlight lock protecting the
- * ops pointer and no code outside the core should need to touch it.
- *
- * Access to update_status() is serialised by the update_lock mutex since
- * most drivers seem to need this and historically get it wrong.
- *
- * Most drivers don't need locking on their get_brightness() method.
- * If yours does, you need to implement it in the driver. You can use the
- * update_lock mutex if appropriate.
- *
- * Any other use of the locks below is probably wrong.
- */
-
enum backlight_update_reason {
BACKLIGHT_UPDATE_HOTKEY,
BACKLIGHT_UPDATE_SYSFS,
@@ -215,30 +200,71 @@ struct backlight_properties {
enum backlight_scale scale;
};
+/**
+ * struct backlight_device - backlight device data
+ *
+ * This structure holds all data required by a backlight device.
+ */
struct backlight_device {
- /* Backlight properties */
+ /**
+ * @props: Backlight properties
+ */
struct backlight_properties props;
- /* Serialise access to update_status method */
+ /**
+ * @update_lock: The lock used when calling the update_status() operation.
+ *
+ * update_lock is an internal backlight lock that serialise access
+ * to the update_status() operation. The backlight core holds the update_lock
+ * when calling the update_status() operation. The update_lock shall not
+ * be used by backlight drivers.
+ */
struct mutex update_lock;
- /* This protects the 'ops' field. If 'ops' is NULL, the driver that
- registered this device has been unloaded, and if class_get_devdata()
- points to something in the body of that driver, it is also invalid. */
+ /**
+ * @ops_lock: The lock used around everything related to backlight_ops.
+ *
+ * ops_lock is an internal backlight lock that protects the ops pointer
+ * and is used around all accesses to ops and when the operations are
+ * invoked. The ops_lock shall not be used by backlight drivers.
+ */
struct mutex ops_lock;
+
+ /**
+ * @ops: Pointer to the backlight operations.
+ *
+ * If ops is NULL, the driver that registered this device has been unloaded,
+ * and if class_get_devdata() points to something in the body of that driver,
+ * it is also invalid.
+ */
const struct backlight_ops *ops;
- /* The framebuffer notifier block */
+ /**
+ * @fb_notif: The framebuffer notifier block
+ */
struct notifier_block fb_notif;
- /* list entry of all registered backlight devices */
+ /**
+ * @entry: List entry of all registered backlight devices
+ */
struct list_head entry;
+ /**
+ * @dev: Parent device.
+ */
struct device dev;
- /* Multiple framebuffers may share one backlight device */
+ /**
+ * @fb_bl_on: The state of individual fbdev's.
+ *
+ * Multiple fbdev's may share one backlight device. The fb_bl_on
+ * records the state of the individual fbdev.
+ */
bool fb_bl_on[FB_MAX];
+ /**
+ * @use_count: The number of uses of fb_bl_on.
+ */
int use_count;
};