media: docs: move uAPI book to userspace-api/media

Since 2017, there is an space reserved for userspace API,
created by changeset 1d596dee3862 ("docs: Create a user-space API guide").

As the media subsystem was one of the first subsystems to use
Sphinx, until this patch, we were keeping things on a separate
place.

Let's just use the new location, as having all uAPI altogether
will likely make things easier for developers.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

1 files changed, 31 insertions, 0 deletions

diff --git a/Documentation/userspace-api/media/v4l/pixfmt-cnf4.rst b/Documentation/userspace-api/media/v4l/pixfmt-cnf4.rst
new file mode 100644
index 000000000000..8f469290c304
--- /dev/null
+++ b/Documentation/userspace-api/media/v4l/pixfmt-cnf4.rst
@@ -0,0 +1,31 @@
+.. -*- coding: utf-8; mode: rst -*-
+
+.. _V4L2-PIX-FMT-CNF4:
+
+******************************
+V4L2_PIX_FMT_CNF4 ('CNF4')
+******************************
+
+Depth sensor confidence information as a 4 bits per pixel packed array
+
+Description
+===========
+
+Proprietary format used by Intel RealSense Depth cameras containing depth
+confidence information in range 0-15 with 0 indicating that the sensor was
+unable to resolve any signal and 15 indicating maximum level of confidence for
+the specific sensor (actual error margins might change from sensor to sensor).
+
+Every two consecutive pixels are packed into a single byte.
+Bits 0-3 of byte n refer to confidence value of depth pixel 2*n,
+bits 4-7 to confidence value of depth pixel 2*n+1.
+
+**Bit-packed representation.**
+
+.. flat-table::
+    :header-rows:  0
+    :stub-columns: 0
+    :widths: 64 64
+
+    * - Y'\ :sub:`01[3:0]`\ (bits 7--4) Y'\ :sub:`00[3:0]`\ (bits 3--0)
+      - Y'\ :sub:`03[3:0]`\ (bits 7--4) Y'\ :sub:`02[3:0]`\ (bits 3--0)