Hi
Am 24.06.26 um 18:57 schrieb Mario Limonciello:
From: "Mario Limonciello (AMD)" <[email protected]>
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]>
Tested-by: Simon Ser <[email protected]>
I don't like this, but I don't have a better idea for now. Therefore
Reviewed-by: Thomas Zimmermann <[email protected]>
until a better idea shows up.
---
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 a22d0bbb6e639..ff2c2084c73a4 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 f29a9ef1052e7..d905173c7f73c 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,
--
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstr. 146, 90461 Nürnberg, Germany, www.suse.com
GF: Jochen Jaser, Andrew McDonald, Werner Knoblich, (HRB 36809, AG Nürnberg)
