[PATCH 2/4] media: v4l2-mc add v4l_change_media_source() to invoke change_source

[Shuah Khan]

Add a common routine to invoke media device change_source handler.

Signed-off-by: Shuah Khan <shua...@osg.samsung.com>
---
 drivers/media/v4l2-core/v4l2-mc.c | 14 ++++++++++++++
 include/media/v4l2-mc.h           | 20 +++++++++++++++++++-
 2 files changed, 33 insertions(+), 1 deletion(-)

diff --git a/drivers/media/v4l2-core/v4l2-mc.c 
b/drivers/media/v4l2-core/v4l2-mc.c
index ae661ac..478b2768 100644
--- a/drivers/media/v4l2-core/v4l2-mc.c
+++ b/drivers/media/v4l2-core/v4l2-mc.c
@@ -217,6 +217,20 @@ void v4l_disable_media_source(struct video_device *vdev)
 }
 EXPORT_SYMBOL_GPL(v4l_disable_media_source);
 
+int v4l_change_media_source(struct video_device *vdev)
+{
+       struct media_device *mdev = vdev->entity.graph_obj.mdev;
+       int ret;
+
+       if (!mdev || !mdev->change_source)
+               return 0;
+       ret = mdev->change_source(&vdev->entity, &vdev->pipe);
+       if (ret)
+               return -EBUSY;
+       return 0;
+}
+EXPORT_SYMBOL_GPL(v4l_change_media_source);
+
 int v4l_vb2q_enable_media_source(struct vb2_queue *q)
 {
        struct v4l2_fh *fh = q->owner;
diff --git a/include/media/v4l2-mc.h b/include/media/v4l2-mc.h
index 98a938a..884b969 100644
--- a/include/media/v4l2-mc.h
+++ b/include/media/v4l2-mc.h
@@ -154,8 +154,26 @@ int v4l_enable_media_source(struct video_device *vdev);
  */
 void v4l_disable_media_source(struct video_device *vdev);
 
+/**
+ * v4l_change_media_source() - Hold media source for exclusive use
+ *                             if free
+ *
+ * @vdev:      pointer to struct video_device
+ *
+ * This interface calls change_source handler to change
+ * the current source it is holding. The change_source
+ * disables the current source and starts pipeline to
+ * the new source. This interface should be used when
+ * user changes source using s_input handler to keep
+ * the previously granted permission for exclusive use
+ * with a new input source.
+ *
+ * Return: returns zero on success or a negative error code.
+ */
+int v4l_change_media_source(struct video_device *vdev);
+
 /*
- * v4l_vb2q_enable_media_tuner -  Hold media source for exclusive use
+ * v4l_vb2q_enable_media_source - Hold media source for exclusive use
  *                               if free.
  * @q - pointer to struct vb2_queue
  *
-- 
2.5.0