Update Linux to v5.4.2
Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/Documentation/media/v4l-drivers/vimc.rst b/Documentation/media/v4l-drivers/vimc.rst
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+.. SPDX-License-Identifier: GPL-2.0
+
+The Virtual Media Controller Driver (vimc)
+==========================================
+
+The vimc driver emulates complex video hardware using the V4L2 API and the Media
+API. It has a capture device and three subdevices: sensor, debayer and scaler.
+
+Topology
+--------
+
+The topology is hardcoded, although you could modify it in vimc-core and
+recompile the driver to achieve your own topology. This is the default topology:
+
+.. _vimc_topology_graph:
+
+.. kernel-figure:: vimc.dot
+ :alt: Diagram of the default media pipeline topology
+ :align: center
+
+ Media pipeline graph on vimc
+
+Configuring the topology
+~~~~~~~~~~~~~~~~~~~~~~~~
+
+Each subdevice will come with its default configuration (pixelformat, height,
+width, ...). One needs to configure the topology in order to match the
+configuration on each linked subdevice to stream frames through the pipeline.
+If the configuration doesn't match, the stream will fail. The ``v4l-utils``
+package is a bundle of user-space applications, that comes with ``media-ctl`` and
+``v4l2-ctl`` that can be used to configure the vimc configuration. This sequence
+of commands fits for the default topology:
+
+.. code-block:: bash
+
+ media-ctl -d platform:vimc -V '"Sensor A":0[fmt:SBGGR8_1X8/640x480]'
+ media-ctl -d platform:vimc -V '"Debayer A":0[fmt:SBGGR8_1X8/640x480]'
+ media-ctl -d platform:vimc -V '"Sensor B":0[fmt:SBGGR8_1X8/640x480]'
+ media-ctl -d platform:vimc -V '"Debayer B":0[fmt:SBGGR8_1X8/640x480]'
+ v4l2-ctl -z platform:vimc -d "RGB/YUV Capture" -v width=1920,height=1440
+ v4l2-ctl -z platform:vimc -d "Raw Capture 0" -v pixelformat=BA81
+ v4l2-ctl -z platform:vimc -d "Raw Capture 1" -v pixelformat=BA81
+
+Subdevices
+----------
+
+Subdevices define the behavior of an entity in the topology. Depending on the
+subdevice, the entity can have multiple pads of type source or sink.
+
+vimc-sensor:
+ Generates images in several formats using video test pattern generator.
+ Exposes:
+
+ * 1 Pad source
+
+vimc-debayer:
+ Transforms images in bayer format into a non-bayer format.
+ Exposes:
+
+ * 1 Pad sink
+ * 1 Pad source
+
+vimc-scaler:
+ Scale up the image by a factor of 3. E.g.: a 640x480 image becomes a
+ 1920x1440 image. (this value can be configured, see at
+ `Module options`_).
+ Exposes:
+
+ * 1 Pad sink
+ * 1 Pad source
+
+vimc-capture:
+ Exposes node /dev/videoX to allow userspace to capture the stream.
+ Exposes:
+
+ * 1 Pad sink
+ * 1 Pad source
+
+Module options
+---------------
+
+Vimc has a few module parameters to configure the driver. You should pass
+those arguments to each subdevice, not to the vimc module. For example::
+
+ vimc_subdevice.param=value
+
+* ``vimc_scaler.sca_mult=<unsigned int>``
+
+ Image size multiplier factor to be used to multiply both width and
+ height, so the image size will be ``sca_mult^2`` bigger than the
+ original one. Currently, only supports scaling up (the default value
+ is 3).
+
+* ``vimc_debayer.deb_mean_win_size=<unsigned int>``
+
+ Window size to calculate the mean. Note: the window size needs to be an
+ odd number, as the main pixel stays in the center of the window,
+ otherwise the next odd number is considered (the default value is 3).
+
+Source code documentation
+-------------------------
+
+vimc-streamer
+~~~~~~~~~~~~~
+
+.. kernel-doc:: drivers/media/platform/vimc/vimc-streamer.h
+ :internal:
+
+.. kernel-doc:: drivers/media/platform/vimc/vimc-streamer.c