v4 is now rebased on top of latest media master which has moved documentation around quite a bit. v4 includes two patches originally from Hans to add support for SUBDEV_QUERYCAP ioctl. Compared to its initial version only capabilities flags and version are reported. https://git.linuxtv.org/hverkuil/media_tree.git/log/?h=subdev-querycap I chose to report both the RO and RW capabilities flag to make it possible for userspace to test on both cases, as RW was the 'standard' so far, the flag could be removed if considered not necessary. Checkpatch reports: WARNING: LINUX_VERSION_CODE should be avoided, code should be for the version to which it is merged #44: FILE: drivers/media/v4l2-core/v4l2-subdev.c:344: + cap->version = LINUX_VERSION_CODE; but I see LINUX_VERSION_CODE being used to version the media controller as well, so I assume it's a false positive. Copy of the old cover letter is below reported: ------------------------------------------------------------------------------- Add new function v4l2_device_register_ro_subdev_nodes() to pair with v4l2_device_register_subdev_nodes() that allows a bridge driver to register the device node for its subdevices in read-only mode. Devnode-centric (aka non-MC) bridge drivers control their subdevices through direct calls to v4l2 subdev operations and do not want userspace to be able to control the subdevice configuration by calling ioctls on the sub-device devnode. For this reason, they usually refrain from registering any devnode at all for their subdevices. However it is sometimes required for userspace to access the sub-dev device nodes to collect information on the actual configuration, without changing the one currently applied to the device. This requirement became pressing while working on libcamera on devnode-centric platforms that do not expose any sub-device for their camera sensor to prevent userspace from changing their configuration. To allow them to register device node and being guaranteed to retain control of the subdevice configuration this series proposes a way to register device nodes in read-only to restrict access to all ioctls that could potentially affect the sub-dev configuration. ------------------------------------------------------------------------------- Thanks j v3->v4: - Rebase v3 on latest media master and new documentation layout - Add SUBDEV_QUERYCAP support v2->v3: - Add Sakari's ack to the series - Documentation: - Address Sakari' and Hans suggestions - Implementation: - Rename V4L2_FL_RO_DEVNODE to V4L2_FL_SUBDEV_RO_DEVNODE - Limit the ability to register sub-device video device nodes to driver claiming support for CONFIG_VIDEO_V4L2_SUBDEV_API v1->v2: - Documentation: - Add a new patch using Laurent's suggestion to update the sub-device userspace API introduction - Take in some of Laurent's suggestions in v4l2-subdev.rst and add a new section in dev-subdev.rst - Implementation: - As noted by Andrey, V4L2_FL_* are meant to be used as bitmasks. Use test_bit()/set_bit() as the rest of the v4l2 core does. It's a bit an overkill compared to use plain BIT() as noted by Sakari but I preferred consistency with the rest of the core - Make v4l2_device_register_subdev_nodes() and v4l2_device_register_ro_subdev_nodes() to v4l2-device.h and make them inline functions. Documentation style has been copied from other functions with similar implementations, such as __video_register_device() in v4l2-dev.h Hans Verkuil (2): v4l2-subdev: add VIDIOC_SUBDEV_QUERYCAP ioctl v4l: document VIDIOC_SUBDEV_QUERYCAP Jacopo Mondi (3): Documentation: media: Update sub-device API intro Documentation: media: Document read-only subdevice media: v4l2-dev: Add v4l2_device_register_ro_subdev_node() .../driver-api/media/v4l2-subdev.rst | 53 +++++++- .../userspace-api/media/v4l/dev-subdev.rst | 5 + .../userspace-api/media/v4l/user-func.rst | 1 + .../media/v4l/vidioc-g-dv-timings.rst | 6 + .../userspace-api/media/v4l/vidioc-g-std.rst | 6 + .../media/v4l/vidioc-subdev-g-crop.rst | 9 ++ .../media/v4l/vidioc-subdev-g-fmt.rst | 8 ++ .../v4l/vidioc-subdev-g-frame-interval.rst | 8 ++ .../media/v4l/vidioc-subdev-g-selection.rst | 8 ++ .../media/v4l/vidioc-subdev-querycap.rst | 114 ++++++++++++++++++ drivers/media/v4l2-core/v4l2-device.c | 7 +- drivers/media/v4l2-core/v4l2-subdev.c | 31 +++++ include/media/v4l2-dev.h | 7 ++ include/media/v4l2-device.h | 50 +++++++- include/uapi/linux/v4l2-subdev.h | 15 +++ 15 files changed, 320 insertions(+), 8 deletions(-) create mode 100644 Documentation/userspace-api/media/v4l/vidioc-subdev-querycap.rst -- 2.26.1
