1 files changed, 56 insertions, 0 deletions

diff --git a/drivers/media/media-device.c b/drivers/media/media-device.c
index bcd3985d415a..a36509a1df09 100644
--- a/drivers/media/media-device.c
+++ b/drivers/media/media-device.c
@@ -25,6 +25,7 @@
 
 #include <media/media-device.h>
 #include <media/media-devnode.h>
+#include <media/media-entity.h>
 
 static const struct media_file_operations media_device_fops = {
         .owner = THIS_MODULE,
@@ -69,6 +70,10 @@ int __must_check media_device_register(struct media_device *mdev)
         if (WARN_ON(mdev->dev == NULL || mdev->model[0] == 0))
                 return -EINVAL;
 
+        mdev->entity_id = 1;
+        INIT_LIST_HEAD(&mdev->entities);
+        spin_lock_init(&mdev->lock);
+
         /* Register the device node. */
         mdev->devnode.fops = &media_device_fops;
         mdev->devnode.parent = mdev->dev;
@@ -94,7 +99,58 @@ EXPORT_SYMBOL_GPL(media_device_register);
  */
 void media_device_unregister(struct media_device *mdev)
 {
+        struct media_entity *entity;
+        struct media_entity *next;
+
+        list_for_each_entry_safe(entity, next, &mdev->entities, list)
+                media_device_unregister_entity(entity);
+
         device_remove_file(&mdev->devnode.dev, &dev_attr_model);
         media_devnode_unregister(&mdev->devnode);
 }
 EXPORT_SYMBOL_GPL(media_device_unregister);
+
+/**
+ * media_device_register_entity - Register an entity with a media device
+ * @mdev:       The media device
+ * @entity:     The entity
+ */
+int __must_check media_device_register_entity(struct media_device *mdev,
+                                              struct media_entity *entity)
+{
+        /* Warn if we apparently re-register an entity */
+        WARN_ON(entity->parent != NULL);
+        entity->parent = mdev;
+
+        spin_lock(&mdev->lock);
+        if (entity->id == 0)
+                entity->id = mdev->entity_id++;
+        else
+                mdev->entity_id = max(entity->id + 1, mdev->entity_id);
+        list_add_tail(&entity->list, &mdev->entities);
+        spin_unlock(&mdev->lock);
+
+        return 0;
+}
+EXPORT_SYMBOL_GPL(media_device_register_entity);
+
+/**
+ * media_device_unregister_entity - Unregister an entity
+ * @entity:     The entity
+ *
+ * If the entity has never been registered this function will return
+ * immediately.
+ */
+void media_device_unregister_entity(struct media_entity *entity)
+{
+        struct media_device *mdev = entity->parent;
+
+        if (mdev == NULL)
+                return;
+
+        spin_lock(&mdev->lock);
+        list_del(&entity->list);
+        spin_unlock(&mdev->lock);
+        entity->parent = NULL;
+}
+EXPORT_SYMBOL_GPL(media_device_unregister_entity);