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

The following CEC error injection implementations exist:

- Documentation/media/uapi/cec/cec-pin-error-inj.rst

- Documentation/userspace-api/media/cec/cec-pin-error-inj.rst

loop_cmd = $(echo-cmd) $(cmd_$(1)) || exit;

# $2 sphinx builder e.g. "html"

# $3 name of the build subfolder / e.g. "media", used as:

# $3 name of the build subfolder / e.g. "userspace-api/media", used as:

#    * dest folder relative to $(BUILDDIR) and

#    * cache folder relative to $(BUILDDIR)/.doctrees

# $4 dest subfolder e.g. "man" for man pages at media/man

# $4 dest subfolder e.g. "man" for man pages at userspace-api/media/man

# $5 reST source folder relative to $(srctree)/$(src),

#    e.g. "media" for the linux-tv book-set at ./Documentation/media

#    e.g. "userspace-api/media" for the linux-tv book-set at ./Documentation/userspace-api/media

quiet_cmd_sphinx = SPHINX  $@ --> file://$(abspath $(BUILDDIR)/$3/$4)

      cmd_sphinx = $(MAKE) BUILDDIR=$(abspath $(BUILDDIR)) $(build)=Documentation/media $2 && \

      cmd_sphinx = $(MAKE) BUILDDIR=$(abspath $(BUILDDIR)) $(build)=Documentation/userspace-api/media $2 && \

	PYTHONDONTWRITEBYTECODE=1 \

	BUILDDIR=$(abspath $(BUILDDIR)) SPHINX_CONF=$(abspath $(srctree)/$(src)/$5/$(SPHINX_CONF)) \

	$(PYTHON) $(srctree)/scripts/jobserver-exec \

cleandocs:

	$(Q)rm -rf $(BUILDDIR)

	$(Q)$(MAKE) BUILDDIR=$(abspath $(BUILDDIR)) $(build)=Documentation/media clean

	$(Q)$(MAKE) BUILDDIR=$(abspath $(BUILDDIR)) $(build)=Documentation/userspace-api/media clean

dochelp:

	@echo  ' Linux kernel internal documentation in different formats from ReST:'

uAPI documentation in sync with the Kernel changes.

The :ref:`parse_headers.pl <parse_headers>` provide a way to generate such

cross-references. It has to be called via Makefile, while building the

documentation. Please see ``Documentation/media/Makefile`` for an example

documentation. Please see ``Documentation/userspace-api/media/Makefile`` for an example

about how to use it inside the Kernel tree.

.. _parse_headers:

FOURCC definitions are located in the linux/videodev2.h header. However, and

despite starting with the V4L2_PIX_FMT_prefix, they are not restricted to V4L2

and don't require usage of the V4L2 subsystem. FOURCC documentation is

available in Documentation/media/uapi/v4l/pixfmt.rst.

available in Documentation/userspace-api/media/v4l/pixfmt.rst.

To select a format, applications set the grayscale field to the desired FOURCC.

For YUV formats, they should also select the appropriate colorspace by setting

the colorspace field to one of the colorspaces listed in linux/videodev2.h and

documented in Documentation/media/uapi/v4l/colorspaces.rst.

documented in Documentation/userspace-api/media/v4l/colorspaces.rst.

The red, green, blue and transp fields are not used with the FOURCC-based API.

For forward compatibility reasons applications must zero those fields, and

.. toctree::

   :maxdepth: 2

   media_uapi

   ../userspace-api/media/index

   media_kapi

   dvb-drivers/index

   v4l-drivers/index