[media] doc-rst: linux_tv CEC part, DocBook to reST migration

This is the reST migration of media's CEC part.  The migration is based
on media_tree's cec branch:

 https://git.linuxtv.org/media_tree.git

 c7169ad * cec media_tree/cec [media] DocBook/media: add CEC documentation

Signed-off-by: Markus Heiser <markus.heiser@darmarIT.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

1 files changed, 311 insertions, 0 deletions

diff --git a/Documentation/media/uapi/cec/cec-ioc-g-mode.rst b/Documentation/media/uapi/cec/cec-ioc-g-mode.rst
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+.. -*- coding: utf-8; mode: rst -*-
+
+.. _cec-ioc-g-mode:
+
+****************************
+ioctl CEC_G_MODE, CEC_S_MODE
+****************************
+
+*man CEC_G_MODE(2)*
+
+CEC_S_MODE
+Get or set exclusive use of the CEC adapter
+
+
+Synopsis
+========
+
+.. c:function:: int ioctl( int fd, int request, __u32 *argp )
+
+Arguments
+=========
+
+``fd``
+    File descriptor returned by :ref:`open() <cec-func-open>`.
+
+``request``
+    CEC_G_MODE, CEC_S_MODE
+
+``argp``
+
+
+Description
+===========
+
+Note: this documents the proposed CEC API. This API is not yet finalized
+and is currently only available as a staging kernel module.
+
+By default any filehandle can use
+:ref:`CEC_TRANSMIT <cec-ioc-receive>` and
+:ref:`CEC_RECEIVE <cec-ioc-receive>`, but in order to prevent
+applications from stepping on each others toes it must be possible to
+obtain exclusive access to the CEC adapter. This ioctl sets the
+filehandle to initiator and/or follower mode which can be exclusive
+depending on the chosen mode. The initiator is the filehandle that is
+used to initiate messages, i.e. it commands other CEC devices. The
+follower is the filehandle that receives messages sent to the CEC
+adapter and processes them. The same filehandle can be both initiator
+and follower, or this role can be taken by two different filehandles.
+
+When a CEC message is received, then the CEC framework will decide how
+it will be processed. If the message is a reply to an earlier
+transmitted message, then the reply is sent back to the filehandle that
+is waiting for it. In addition the CEC framework will process it.
+
+If the message is not a reply, then the CEC framework will process it
+first. If there is no follower, then the message is just discarded and a
+feature abort is sent back to the initiator if the framework couldn't
+process it. If there is a follower, then the message is passed on to the
+follower who will use :ref:`CEC_RECEIVE <cec-ioc-receive>` to dequeue
+the new message. The framework expects the follower to make the right
+decisions.
+
+The CEC framework will process core messages unless requested otherwise
+by the follower. The follower can enable the passthrough mode. In that
+case, the CEC framework will pass on most core messages without
+processing them and the follower will have to implement those messages.
+There are some messages that the core will always process, regardless of
+the passthrough mode. See :ref:`cec-core-processing` for details.
+
+If there is no initiator, then any CEC filehandle can use
+:ref:`CEC_TRANSMIT <cec-ioc-receive>`. If there is an exclusive
+initiator then only that initiator can call
+:ref:`CEC_TRANSMIT <cec-ioc-receive>`. The follower can of course
+always call :ref:`CEC_TRANSMIT <cec-ioc-receive>`.
+
+Available initiator modes are:
+
+
+.. _cec-mode-initiator:
+
+.. flat-table:: Initiator Modes
+    :header-rows:  0
+    :stub-columns: 0
+    :widths:       3 1 4
+
+
+    -  .. row 1
+
+       -  ``CEC_MODE_NO_INITIATOR``
+
+       -  0x0
+
+       -  This is not an initiator, i.e. it cannot transmit CEC messages or
+          make any other changes to the CEC adapter.
+
+    -  .. row 2
+
+       -  ``CEC_MODE_INITIATOR``
+
+       -  0x1
+
+       -  This is an initiator (the default when the device is opened) and
+          it can transmit CEC messages and make changes to the CEC adapter,
+          unless there is an exclusive initiator.
+
+    -  .. row 3
+
+       -  ``CEC_MODE_EXCL_INITIATOR``
+
+       -  0x2
+
+       -  This is an exclusive initiator and this file descriptor is the
+          only one that can transmit CEC messages and make changes to the
+          CEC adapter. If someone else is already the exclusive initiator
+          then an attempt to become one will return the EBUSY error code
+          error.
+
+
+Available follower modes are:
+
+
+.. _cec-mode-follower:
+
+.. flat-table:: Follower Modes
+    :header-rows:  0
+    :stub-columns: 0
+    :widths:       3 1 4
+
+
+    -  .. row 1
+
+       -  ``CEC_MODE_NO_FOLLOWER``
+
+       -  0x00
+
+       -  This is not a follower (the default when the device is opened).
+
+    -  .. row 2
+
+       -  ``CEC_MODE_FOLLOWER``
+
+       -  0x10
+
+       -  This is a follower and it will receive CEC messages unless there
+          is an exclusive follower. You cannot become a follower if
+          ``CEC_CAP_TRANSMIT`` is not set or if ``CEC_MODE_NO_INITIATOR``
+          was specified, EINVAL error code is returned in that case.
+
+    -  .. row 3
+
+       -  ``CEC_MODE_EXCL_FOLLOWER``
+
+       -  0x20
+
+       -  This is an exclusive follower and only this file descriptor will
+          receive CEC messages for processing. If someone else is already
+          the exclusive follower then an attempt to become one will return
+          the EBUSY error code error. You cannot become a follower if
+          ``CEC_CAP_TRANSMIT`` is not set or if ``CEC_MODE_NO_INITIATOR``
+          was specified, EINVAL error code is returned in that case.
+
+    -  .. row 4
+
+       -  ``CEC_MODE_EXCL_FOLLOWER_PASSTHRU``
+
+       -  0x30
+
+       -  This is an exclusive follower and only this file descriptor will
+          receive CEC messages for processing. In addition it will put the
+          CEC device into passthrough mode, allowing the exclusive follower
+          to handle most core messages instead of relying on the CEC
+          framework for that. If someone else is already the exclusive
+          follower then an attempt to become one will return the EBUSY error
+          code error. You cannot become a follower if ``CEC_CAP_TRANSMIT``
+          is not set or if ``CEC_MODE_NO_INITIATOR`` was specified, EINVAL
+          error code is returned in that case.
+
+    -  .. row 5
+
+       -  ``CEC_MODE_MONITOR``
+
+       -  0xe0
+
+       -  Put the file descriptor into monitor mode. Can only be used in
+          combination with ``CEC_MODE_NO_INITIATOR``, otherwise EINVAL error
+          code will be returned. In monitor mode all messages this CEC
+          device transmits and all messages it receives (both broadcast
+          messages and directed messages for one its logical addresses) will
+          be reported. This is very useful for debugging. This is only
+          allowed if the process has the ``CAP_NET_ADMIN`` capability. If
+          that is not set, then EPERM error code is returned.
+
+    -  .. row 6
+
+       -  ``CEC_MODE_MONITOR_ALL``
+
+       -  0xf0
+
+       -  Put the file descriptor into 'monitor all' mode. Can only be used
+          in combination with ``CEC_MODE_NO_INITIATOR``, otherwise EINVAL
+          error code will be returned. In 'monitor all' mode all messages
+          this CEC device transmits and all messages it receives, including
+          directed messages for other CEC devices will be reported. This is
+          very useful for debugging, but not all devices support this. This
+          mode requires that the ``CEC_CAP_MONITOR_ALL`` capability is set,
+          otherwise EINVAL error code is returned. This is only allowed if
+          the process has the ``CAP_NET_ADMIN`` capability. If that is not
+          set, then EPERM error code is returned.
+
+
+Core message processing details:
+
+
+.. _cec-core-processing:
+
+.. flat-table:: Core Message Processing
+    :header-rows:  0
+    :stub-columns: 0
+
+
+    -  .. row 1
+
+       -  ``CEC_MSG_GET_CEC_VERSION``
+
+       -  When in passthrough mode this message has to be handled by
+          userspace, otherwise the core will return the CEC version that was
+          set with
+          :ref:`CEC_ADAP_S_LOG_ADDRS <cec-ioc-adap-g-log-addrs>`.
+
+    -  .. row 2
+
+       -  ``CEC_MSG_GIVE_DEVICE_VENDOR_ID``
+
+       -  When in passthrough mode this message has to be handled by
+          userspace, otherwise the core will return the vendor ID that was
+          set with
+          :ref:`CEC_ADAP_S_LOG_ADDRS <cec-ioc-adap-g-log-addrs>`.
+
+    -  .. row 3
+
+       -  ``CEC_MSG_ABORT``
+
+       -  When in passthrough mode this message has to be handled by
+          userspace, otherwise the core will return a feature refused
+          message as per the specification.
+
+    -  .. row 4
+
+       -  ``CEC_MSG_GIVE_PHYSICAL_ADDR``
+
+       -  When in passthrough mode this message has to be handled by
+          userspace, otherwise the core will report the current physical
+          address.
+
+    -  .. row 5
+
+       -  ``CEC_MSG_GIVE_OSD_NAME``
+
+       -  When in passthrough mode this message has to be handled by
+          userspace, otherwise the core will report the current OSD name as
+          was set with
+          :ref:`CEC_ADAP_S_LOG_ADDRS <cec-ioc-adap-g-log-addrs>`.
+
+    -  .. row 6
+
+       -  ``CEC_MSG_GIVE_FEATURES``
+
+       -  When in passthrough mode this message has to be handled by
+          userspace, otherwise the core will report the current features as
+          was set with
+          :ref:`CEC_ADAP_S_LOG_ADDRS <cec-ioc-adap-g-log-addrs>` or
+          the message is ignore if the CEC version was older than 2.0.
+
+    -  .. row 7
+
+       -  ``CEC_MSG_USER_CONTROL_PRESSED``
+
+       -  If ``CEC_CAP_RC`` is set, then generate a remote control key
+          press. This message is always passed on to userspace.
+
+    -  .. row 8
+
+       -  ``CEC_MSG_USER_CONTROL_RELEASED``
+
+       -  If ``CEC_CAP_RC`` is set, then generate a remote control key
+          release. This message is always passed on to userspace.
+
+    -  .. row 9
+
+       -  ``CEC_MSG_REPORT_PHYSICAL_ADDR``
+
+       -  The CEC framework will make note of the reported physical address
+          and then just pass the message on to userspace.
+
+
+
+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.
+
+
+.. ------------------------------------------------------------------------------
+.. This file was automatically converted from DocBook-XML with the dbxml
+.. library (https://github.com/return42/sphkerneldoc). The origin XML comes
+.. from the linux kernel, refer to:
+..
+.. * https://github.com/torvalds/linux/tree/master/Documentation/DocBook
+.. ------------------------------------------------------------------------------