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Diffstat (limited to 'Documentation/userspace-api/media/cec/cec-ioc-adap-g-phys-addr.rst')
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diff --git a/Documentation/userspace-api/media/cec/cec-ioc-adap-g-phys-addr.rst b/Documentation/userspace-api/media/cec/cec-ioc-adap-g-phys-addr.rst new file mode 100644 index 0000000000..fb22f6894f --- /dev/null +++ b/Documentation/userspace-api/media/cec/cec-ioc-adap-g-phys-addr.rst @@ -0,0 +1,94 @@ +.. 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. |