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diff --git a/Documentation/media/uapi/mediactl/media-ioc-enum-entities.rst b/Documentation/media/uapi/mediactl/media-ioc-enum-entities.rst new file mode 100644 index 0000000..ae88f46 --- /dev/null +++ b/Documentation/media/uapi/mediactl/media-ioc-enum-entities.rst @@ -0,0 +1,197 @@ +.. -*- coding: utf-8; mode: rst -*- + +.. _media-ioc-enum-entities: + +***************************** +ioctl MEDIA_IOC_ENUM_ENTITIES +***************************** + +Name +==== + +MEDIA_IOC_ENUM_ENTITIES - Enumerate entities and their properties + + +Synopsis +======== + +.. cpp:function:: int ioctl( int fd, int request, struct media_entity_desc *argp ) + + +Arguments +========= + +``fd`` + File descriptor returned by :ref:`open() <media-func-open>`. + +``request`` + MEDIA_IOC_ENUM_ENTITIES + +``argp`` + + +Description +=========== + +To query the attributes of an entity, applications set the id field of a +struct :ref:`media_entity_desc <media-entity-desc>` structure and +call the MEDIA_IOC_ENUM_ENTITIES ioctl with a pointer to this +structure. The driver fills the rest of the structure or returns an +EINVAL error code when the id is invalid. + +Entities can be enumerated by or'ing the id with the +``MEDIA_ENT_ID_FLAG_NEXT`` flag. The driver will return information +about the entity with the smallest id strictly larger than the requested +one ('next entity'), or the ``EINVAL`` error code if there is none. + +Entity IDs can be non-contiguous. Applications must *not* try to +enumerate entities by calling MEDIA_IOC_ENUM_ENTITIES with increasing +id's until they get an error. + + +.. _media-entity-desc: + +.. flat-table:: struct media_entity_desc + :header-rows: 0 + :stub-columns: 0 + :widths: 1 1 1 1 8 + + + - .. row 1 + + - __u32 + + - ``id`` + + - + - + - Entity id, set by the application. When the id is or'ed with + ``MEDIA_ENT_ID_FLAG_NEXT``, the driver clears the flag and returns + the first entity with a larger id. + + - .. row 2 + + - char + + - ``name``\ [32] + + - + - + - Entity name as an UTF-8 NULL-terminated string. + + - .. row 3 + + - __u32 + + - ``type`` + + - + - + - Entity type, see :ref:`media-entity-type` for details. + + - .. row 4 + + - __u32 + + - ``revision`` + + - + - + - Entity revision. Always zero (obsolete) + + - .. row 5 + + - __u32 + + - ``flags`` + + - + - + - Entity flags, see :ref:`media-entity-flag` for details. + + - .. row 6 + + - __u32 + + - ``group_id`` + + - + - + - Entity group ID. Always zero (obsolete) + + - .. row 7 + + - __u16 + + - ``pads`` + + - + - + - Number of pads + + - .. row 8 + + - __u16 + + - ``links`` + + - + - + - Total number of outbound links. Inbound links are not counted in + this field. + + - .. row 9 + + - union + + - .. row 10 + + - + - struct + + - ``dev`` + + - + - Valid for (sub-)devices that create a single device node. + + - .. row 11 + + - + - + - __u32 + + - ``major`` + + - Device node major number. + + - .. row 12 + + - + - + - __u32 + + - ``minor`` + + - Device node minor number. + + - .. row 13 + + - + - __u8 + + - ``raw``\ [184] + + - + - + + +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. + +EINVAL + The struct :ref:`media_entity_desc <media-entity-desc>` ``id`` + references a non-existing entity. |