summaryrefslogtreecommitdiffstats
path: root/Documentation/userspace-api/media/mediactl/media-ioc-enum-entities.rst
diff options
context:
space:
mode:
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
commit5d1646d90e1f2cceb9f0828f4b28318cd0ec7744 (patch)
treea94efe259b9009378be6d90eb30d2b019d95c194 /Documentation/userspace-api/media/mediactl/media-ioc-enum-entities.rst
parentInitial commit. (diff)
downloadlinux-5d1646d90e1f2cceb9f0828f4b28318cd0ec7744.tar.xz
linux-5d1646d90e1f2cceb9f0828f4b28318cd0ec7744.zip
Adding upstream version 5.10.209.upstream/5.10.209
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'Documentation/userspace-api/media/mediactl/media-ioc-enum-entities.rst')
-rw-r--r--Documentation/userspace-api/media/mediactl/media-ioc-enum-entities.rst146
1 files changed, 146 insertions, 0 deletions
diff --git a/Documentation/userspace-api/media/mediactl/media-ioc-enum-entities.rst b/Documentation/userspace-api/media/mediactl/media-ioc-enum-entities.rst
new file mode 100644
index 000000000..92dd8ecd5
--- /dev/null
+++ b/Documentation/userspace-api/media/mediactl/media-ioc-enum-entities.rst
@@ -0,0 +1,146 @@
+.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
+.. c:namespace:: MC
+
+.. _media_ioc_enum_entities:
+
+*****************************
+ioctl MEDIA_IOC_ENUM_ENTITIES
+*****************************
+
+Name
+====
+
+MEDIA_IOC_ENUM_ENTITIES - Enumerate entities and their properties
+
+Synopsis
+========
+
+.. c:macro:: MEDIA_IOC_ENUM_ENTITIES
+
+``int ioctl(int fd, MEDIA_IOC_ENUM_ENTITIES, struct media_entity_desc *argp)``
+
+Arguments
+=========
+
+``fd``
+ File descriptor returned by :c:func:`open()`.
+
+``argp``
+ Pointer to struct :c:type:`media_entity_desc`.
+
+Description
+===========
+
+To query the attributes of an entity, applications set the id field of a
+struct :c:type:`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.
+
+.. _media-ent-id-flag-next:
+
+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.
+
+.. c:type:: media_entity_desc
+
+.. tabularcolumns:: |p{1.5cm}|p{1.7cm}|p{1.6cm}|p{1.5cm}|p{11.2cm}|
+
+.. flat-table:: struct media_entity_desc
+ :header-rows: 0
+ :stub-columns: 0
+ :widths: 2 2 1 8
+
+ * - __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. Do not expect that the ID will
+ always be the same for each instance of the device. In other words,
+ do not hardcode entity IDs in an application.
+
+ * - char
+ - ``name``\ [32]
+ -
+ - Entity name as an UTF-8 NULL-terminated string. This name must be unique
+ within the media topology.
+
+ * - __u32
+ - ``type``
+ -
+ - Entity type, see :ref:`media-entity-functions` for details.
+
+ * - __u32
+ - ``revision``
+ -
+ - Entity revision. Always zero (obsolete)
+
+ * - __u32
+ - ``flags``
+ -
+ - Entity flags, see :ref:`media-entity-flag` for details.
+
+ * - __u32
+ - ``group_id``
+ -
+ - Entity group ID. Always zero (obsolete)
+
+ * - __u16
+ - ``pads``
+ -
+ - Number of pads
+
+ * - __u16
+ - ``links``
+ -
+ - Total number of outbound links. Inbound links are not counted in
+ this field.
+
+ * - __u32
+ - ``reserved[4]``
+ -
+ - Reserved for future extensions. Drivers and applications must set
+ the array to zero.
+
+ * - union {
+ - (anonymous)
+
+ * - struct
+ - ``dev``
+ -
+ - Valid for (sub-)devices that create a single device node.
+
+ * -
+ - __u32
+ - ``major``
+ - Device node major number.
+
+ * -
+ - __u32
+ - ``minor``
+ - Device node minor number.
+
+ * - __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 :c:type:`media_entity_desc` ``id``
+ references a non-existing entity.