1 files changed, 34 insertions, 0 deletions
diff --git a/target/linux/bcm27xx/patches-5.4/950-0637-Documentation-media-Update-sub-device-API-intro.patch b/target/linux/bcm27xx/patches-5.4/950-0637-Documentation-media-Update-sub-device-API-intro.patch
new file mode 100644
index 0000000000..f843a83a7d
--- /dev/null
+++ b/target/linux/bcm27xx/patches-5.4/950-0637-Documentation-media-Update-sub-device-API-intro.patch
@@ -0,0 +1,34 @@
+From afd6952c4dfb0d4945b496ef08b2f478d6f40097 Mon Sep 17 00:00:00 2001
+From: Jacopo Mondi <jacopo@jmondi.org>
+Date: Tue, 7 Apr 2020 17:21:55 +0200
+Subject: [PATCH] Documentation: media: Update sub-device API intro
+
+Update the V4L2 sub-device userspace API introduction to provide more
+details on why complex devices might want to register devnodes for the
+connected subdevices.
+
+Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
+Suggested-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
+Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>
+---
+ Documentation/media/kapi/v4l2-subdev.rst | 9 +++++++--
+ 1 file changed, 7 insertions(+), 2 deletions(-)
+
+--- a/Documentation/media/kapi/v4l2-subdev.rst
++++ b/Documentation/media/kapi/v4l2-subdev.rst
+@@ -275,8 +275,13 @@ system the .unbind() method is called. A
+ V4L2 sub-device userspace API
+ -----------------------------
+ 
+-Beside exposing a kernel API through the :c:type:`v4l2_subdev_ops` structure,
+-V4L2 sub-devices can also be controlled directly by userspace applications.
++Bridge drivers traditionally expose one or multiple video nodes to userspace,
++and control subdevices through the :c:type:`v4l2_subdev_ops` operations in
++response to video node operations. This hides the complexity of the underlying
++hardware from applications. For complex devices, finer-grained control of the
++device than what the video nodes offer may be required. In those cases, bridge
++drivers that implement :ref:`the media controller API <media_controller>` may
++opt for making the subdevice operations directly accessible from userpace.
+ 
+ Device nodes named ``v4l-subdev``\ *X* can be created in ``/dev`` to access
+ sub-devices directly. If a sub-device supports direct userspace configuration