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path: root/drivers/video/backlight/backlight.c
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Diffstat (limited to 'drivers/video/backlight/backlight.c')
-rw-r--r--drivers/video/backlight/backlight.c42
1 files changed, 42 insertions, 0 deletions
diff --git a/drivers/video/backlight/backlight.c b/drivers/video/backlight/backlight.c
index 157057c79ca3..6615ac7fa60a 100644
--- a/drivers/video/backlight/backlight.c
+++ b/drivers/video/backlight/backlight.c
@@ -73,6 +73,27 @@ static inline void backlight_unregister_fb(struct backlight_device *bd)
}
#endif /* CONFIG_FB */
+static void backlight_generate_event(struct backlight_device *bd,
+ enum backlight_update_reason reason)
+{
+ char *envp[2];
+
+ switch (reason) {
+ case BACKLIGHT_UPDATE_SYSFS:
+ envp[0] = "SOURCE=sysfs";
+ break;
+ case BACKLIGHT_UPDATE_HOTKEY:
+ envp[0] = "SOURCE=hotkey";
+ break;
+ default:
+ envp[0] = "SOURCE=unknown";
+ break;
+ }
+ envp[1] = NULL;
+ kobject_uevent_env(&bd->dev.kobj, KOBJ_CHANGE, envp);
+ sysfs_notify(&bd->dev.kobj, NULL, "actual_brightness");
+}
+
static ssize_t backlight_show_power(struct device *dev,
struct device_attribute *attr,char *buf)
{
@@ -142,6 +163,8 @@ static ssize_t backlight_store_brightness(struct device *dev,
}
mutex_unlock(&bd->ops_lock);
+ backlight_generate_event(bd, BACKLIGHT_UPDATE_SYSFS);
+
return rc;
}
@@ -214,6 +237,25 @@ static struct device_attribute bl_device_attributes[] = {
};
/**
+ * backlight_force_update - tell the backlight subsystem that hardware state
+ * has changed
+ * @bd: the backlight device to update
+ *
+ * Updates the internal state of the backlight in response to a hardware event,
+ * and generate a uevent to notify userspace
+ */
+void backlight_force_update(struct backlight_device *bd,
+ enum backlight_update_reason reason)
+{
+ mutex_lock(&bd->ops_lock);
+ if (bd->ops && bd->ops->get_brightness)
+ bd->props.brightness = bd->ops->get_brightness(bd);
+ mutex_unlock(&bd->ops_lock);
+ backlight_generate_event(bd, reason);
+}
+EXPORT_SYMBOL(backlight_force_update);
+
+/**
* backlight_device_register - create and register a new object of
* backlight_device class.
* @name: the name of the new object(must be the same as the name of the