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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-27 10:05:51 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-27 10:05:51 +0000
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treea94efe259b9009378be6d90eb30d2b019d95c194 /Documentation/userspace-api/media/cec/cec-ioc-adap-g-phys-addr.rst
parentInitial commit. (diff)
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Adding upstream version 5.10.209.upstream/5.10.209upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
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+.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
+.. c:namespace:: CEC
+
+.. _CEC_ADAP_PHYS_ADDR:
+.. _CEC_ADAP_G_PHYS_ADDR:
+.. _CEC_ADAP_S_PHYS_ADDR:
+
+****************************************************
+ioctls CEC_ADAP_G_PHYS_ADDR and CEC_ADAP_S_PHYS_ADDR
+****************************************************
+
+Name
+====
+
+CEC_ADAP_G_PHYS_ADDR, CEC_ADAP_S_PHYS_ADDR - Get or set the physical address
+
+Synopsis
+========
+
+.. c:macro:: CEC_ADAP_G_PHYS_ADDR
+
+``int ioctl(int fd, CEC_ADAP_G_PHYS_ADDR, __u16 *argp)``
+
+.. c:macro:: CEC_ADAP_S_PHYS_ADDR
+
+``int ioctl(int fd, CEC_ADAP_S_PHYS_ADDR, __u16 *argp)``
+
+Arguments
+=========
+
+``fd``
+ File descriptor returned by :c:func:`open()`.
+
+``argp``
+ Pointer to the CEC address.
+
+Description
+===========
+
+To query the current physical address applications call
+:ref:`ioctl CEC_ADAP_G_PHYS_ADDR <CEC_ADAP_G_PHYS_ADDR>` with a pointer to a __u16 where the
+driver stores the physical address.
+
+To set a new physical address applications store the physical address in
+a __u16 and call :ref:`ioctl CEC_ADAP_S_PHYS_ADDR <CEC_ADAP_S_PHYS_ADDR>` with a pointer to
+this integer. The :ref:`ioctl CEC_ADAP_S_PHYS_ADDR <CEC_ADAP_S_PHYS_ADDR>` is only available if
+``CEC_CAP_PHYS_ADDR`` is set (the ``ENOTTY`` error code will be returned
+otherwise). The :ref:`ioctl CEC_ADAP_S_PHYS_ADDR <CEC_ADAP_S_PHYS_ADDR>` can only be called
+by a file descriptor in initiator mode (see :ref:`CEC_S_MODE`), if not
+the ``EBUSY`` error code will be returned.
+
+To clear an existing physical address use ``CEC_PHYS_ADDR_INVALID``.
+The adapter will go to the unconfigured state.
+
+If logical address types have been defined (see :ref:`ioctl CEC_ADAP_S_LOG_ADDRS <CEC_ADAP_S_LOG_ADDRS>`),
+then this ioctl will block until all
+requested logical addresses have been claimed. If the file descriptor is in non-blocking mode
+then it will not wait for the logical addresses to be claimed, instead it just returns 0.
+
+A :ref:`CEC_EVENT_STATE_CHANGE <CEC-EVENT-STATE-CHANGE>` event is sent when the physical address
+changes.
+
+The physical address is a 16-bit number where each group of 4 bits
+represent a digit of the physical address a.b.c.d where the most
+significant 4 bits represent 'a'. The CEC root device (usually the TV)
+has address 0.0.0.0. Every device that is hooked up to an input of the
+TV has address a.0.0.0 (where 'a' is ≥ 1), devices hooked up to those in
+turn have addresses a.b.0.0, etc. So a topology of up to 5 devices deep
+is supported. The physical address a device shall use is stored in the
+EDID of the sink.
+
+For example, the EDID for each HDMI input of the TV will have a
+different physical address of the form a.0.0.0 that the sources will
+read out and use as their physical address.
+
+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.
+
+The :ref:`ioctl CEC_ADAP_S_PHYS_ADDR <CEC_ADAP_S_PHYS_ADDR>` can return the following
+error codes:
+
+ENOTTY
+ The ``CEC_CAP_PHYS_ADDR`` capability wasn't set, so this ioctl is not supported.
+
+EBUSY
+ Another filehandle is in exclusive follower or initiator mode, or the filehandle
+ is in mode ``CEC_MODE_NO_INITIATOR``.
+
+EINVAL
+ The physical address is malformed.