Lines Matching +full:sub +full:- +full:nodes
1 .. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
18 The bridge driver exposes one or more V4L2 device nodes
22 the hardware, which may also expose device nodes, called V4L2 sub-devices.
24 When such V4L2 sub-devices are exposed, they allow controlling those
25 other hardware components - usually connected via a serial bus (like
26 I²C, SMBus or SPI). Depending on the bridge driver, those sub-devices
29 :ref:`V4L2 sub-devices <subdev>`.
32 :ref:`Media Controller <media_controller>` are called **MC-centric**
33 devices. The devices that are fully controlled via V4L2 device nodes
34 are called **video-node-centric**.
36 Userspace can check if a V4L2 hardware peripheral is MC-centric by
38 :ref:`device_caps field <device-capabilities>`.
41 then it is MC-centric, otherwise, it is video-node-centric.
43 It is required for MC-centric drivers to identify the V4L2
44 sub-devices and to configure the pipelines via the
46 Also, the sub-devices' configuration shall be controlled via the
47 :ref:`sub-device API <subdev>`.
51 A video-node-centric may still provide media-controller and
52 sub-device interfaces as well.
54 However, in that case the media-controller and the sub-device
55 interfaces are read-only and just provide information about the
56 device. The actual configuration is done via the video nodes.
69 Each driver thus loaded registers one or more device nodes with major
75 The device nodes supported by the Video4Linux subsystem are:
84 ``/dev/v4l-touchX`` Touch sensors
85 ``/dev/v4l-subdevX`` Video sub-devices (used by sensors and other
89 Where ``X`` is a non-negative integer.
93 1. The actual device node name is system-dependent, as udev rules may apply.
97 ``/dev/v4l/by-id/`` and ``/dev/v4l/by-path/`` directories containing
102 ├── by-id
103 │ └── usb-OmniVision._USB_Camera-B4.04.27.1-video-index0 -> ../../video0
104 └── by-path
105 └── pci-0000:00:14.0-usb-0:2:1.0-video-index0 -> ../../video0
107 .. [#] **V4L2 sub-device nodes** (e. g. ``/dev/v4l-subdevX``) use a different
117 .. code-block:: none
130 Normally udev will create the device nodes in /dev automatically for
152 The V4L2 API creates different V4L2 device nodes for each of these functions.
169 provisions to find these related V4L2 device nodes. Some really complex
172 code exists that uses sysfs to discover related V4L2 device nodes (see
174 `v4l-utils <http://git.linuxtv.org/cgit.cgi/v4l-utils.git/>`__ git
176 towards both Media Controller-based devices and devices that do not use
178 linux-media mailing list:
206 the priority mechanism described in :ref:`app-pri`.
222 :ref:`ioctl() <func-ioctl>` function as explained in the following