target/linux/bcm27xx/patches-5.4/950-0644-Documentation-media-Update-sub-device-API-intro.patch

   1 From afd6952c4dfb0d4945b496ef08b2f478d6f40097 Mon Sep 17 00:00:00 2001
   2 From: Jacopo Mondi <jacopo@jmondi.org>
   3 Date: Tue, 7 Apr 2020 17:21:55 +0200
   4 Subject: [PATCH] Documentation: media: Update sub-device API intro
   5
   6 Update the V4L2 sub-device userspace API introduction to provide more
   7 details on why complex devices might want to register devnodes for the
   8 connected subdevices.
   9
  10 Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
  11 Suggested-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
  12 Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>
  13 ---
  14  Documentation/media/kapi/v4l2-subdev.rst | 9 +++++++--
  15  1 file changed, 7 insertions(+), 2 deletions(-)
  16
  17 --- a/Documentation/media/kapi/v4l2-subdev.rst
  18 +++ b/Documentation/media/kapi/v4l2-subdev.rst
  19 @@ -275,8 +275,13 @@ system the .unbind() method is called. A
  20  V4L2 sub-device userspace API
  21  -----------------------------
  22
  23 -Beside exposing a kernel API through the :c:type:`v4l2_subdev_ops` structure,
  24 -V4L2 sub-devices can also be controlled directly by userspace applications.
  25 +Bridge drivers traditionally expose one or multiple video nodes to userspace,
  26 +and control subdevices through the :c:type:`v4l2_subdev_ops` operations in
  27 +response to video node operations. This hides the complexity of the underlying
  28 +hardware from applications. For complex devices, finer-grained control of the
  29 +device than what the video nodes offer may be required. In those cases, bridge
  30 +drivers that implement :ref:`the media controller API <media_controller>` may
  31 +opt for making the subdevice operations directly accessible from userpace.
  32
  33  Device nodes named ``v4l-subdev``\ *X* can be created in ``/dev`` to access
  34  sub-devices directly. If a sub-device supports direct userspace configuration