1 files changed, 144 insertions, 0 deletions
diff --git a/Documentation/media/uapi/v4l/vidioc-subdev-g-selection.rst b/Documentation/media/uapi/v4l/vidioc-subdev-g-selection.rst
new file mode 100644
index 000000000000..50838a4a429e
--- /dev/null
+++ b/Documentation/media/uapi/v4l/vidioc-subdev-g-selection.rst
@@ -0,0 +1,144 @@
+.. -*- coding: utf-8; mode: rst -*-
+
+.. _VIDIOC_SUBDEV_G_SELECTION:
+
+**********************************************************
+ioctl VIDIOC_SUBDEV_G_SELECTION, VIDIOC_SUBDEV_S_SELECTION
+**********************************************************
+
+Name
+====
+
+VIDIOC_SUBDEV_G_SELECTION - VIDIOC_SUBDEV_S_SELECTION - Get or set selection rectangles on a subdev pad
+
+
+Synopsis
+========
+
+.. cpp:function:: int ioctl( int fd, int request, struct v4l2_subdev_selection *argp )
+
+
+Arguments
+=========
+
+``fd``
+    File descriptor returned by :ref:`open() <func-open>`.
+
+``request``
+    VIDIOC_SUBDEV_G_SELECTION, VIDIOC_SUBDEV_S_SELECTION
+
+``argp``
+
+
+Description
+===========
+
+The selections are used to configure various image processing
+functionality performed by the subdevs which affect the image size. This
+currently includes cropping, scaling and composition.
+
+The selection API replaces
+:ref:`the old subdev crop API <VIDIOC_SUBDEV_G_CROP>`. All the
+function of the crop API, and more, are supported by the selections API.
+
+See :ref:`subdev` for more information on how each selection target
+affects the image processing pipeline inside the subdevice.
+
+
+Types of selection targets
+--------------------------
+
+There are two types of selection targets: actual and bounds. The actual
+targets are the targets which configure the hardware. The BOUNDS target
+will return a rectangle that contain all possible actual rectangles.
+
+
+Discovering supported features
+------------------------------
+
+To discover which targets are supported, the user can perform
+``VIDIOC_SUBDEV_G_SELECTION`` on them. Any unsupported target will
+return ``EINVAL``.
+
+Selection targets and flags are documented in
+:ref:`v4l2-selections-common`.
+
+
+.. _v4l2-subdev-selection:
+
+.. flat-table:: struct v4l2_subdev_selection
+    :header-rows:  0
+    :stub-columns: 0
+    :widths:       1 1 2
+
+
+    -  .. row 1
+
+       -  __u32
+
+       -  ``which``
+
+       -  Active or try selection, from enum
+	  :ref:`v4l2_subdev_format_whence <v4l2-subdev-format-whence>`.
+
+    -  .. row 2
+
+       -  __u32
+
+       -  ``pad``
+
+       -  Pad number as reported by the media framework.
+
+    -  .. row 3
+
+       -  __u32
+
+       -  ``target``
+
+       -  Target selection rectangle. See :ref:`v4l2-selections-common`.
+
+    -  .. row 4
+
+       -  __u32
+
+       -  ``flags``
+
+       -  Flags. See :ref:`v4l2-selection-flags`.
+
+    -  .. row 5
+
+       -  struct :ref:`v4l2_rect <v4l2-rect>`
+
+       -  ``r``
+
+       -  Selection rectangle, in pixels.
+
+    -  .. row 6
+
+       -  __u32
+
+       -  ``reserved``\ [8]
+
+       -  Reserved for future extensions. Applications and drivers must set
+	  the array to zero.
+
+
+Return Value
+============
+
+On success 0 is returned, on error -1 and the ``errno`` variable is set
+appropriately. The generic error codes are described at the
+:ref:`Generic Error Codes <gen-errors>` chapter.
+
+EBUSY
+    The selection rectangle can't be changed because the pad is
+    currently busy. This can be caused, for instance, by an active video
+    stream on the pad. The ioctl must not be retried without performing
+    another action to fix the problem first. Only returned by
+    ``VIDIOC_SUBDEV_S_SELECTION``
+
+EINVAL
+    The struct :ref:`v4l2_subdev_selection <v4l2-subdev-selection>`
+    ``pad`` references a non-existing pad, the ``which`` field
+    references a non-existing format, or the selection target is not
+    supported on the given subdev pad.