Hi Jacopo,
On Sat, Apr 18, 2020 at 12:32:16PM +0200, Jacopo Mondi wrote:
> From: Hans Verkuil <hans.verkuil@xxxxxxxxx>
>
> Add documentation for the new VIDIOC_SUBDEV_QUERYCAP ioctl.
>
> Signed-off-by: Hans Verkuil <hans.verkuil@xxxxxxxxx>
> Signed-off-by: Jacopo Mondi <jacopo@xxxxxxxxxx>
> ---
> .../userspace-api/media/v4l/user-func.rst | 1 +
> .../media/v4l/vidioc-subdev-querycap.rst | 114 ++++++++++++++++++
> 2 files changed, 115 insertions(+)
> create mode 100644 Documentation/userspace-api/media/v4l/vidioc-subdev-querycap.rst
>
> diff --git a/Documentation/userspace-api/media/v4l/user-func.rst b/Documentation/userspace-api/media/v4l/user-func.rst
> index f235f88efe89..559cce421d41 100644
> --- a/Documentation/userspace-api/media/v4l/user-func.rst
> +++ b/Documentation/userspace-api/media/v4l/user-func.rst
> @@ -78,6 +78,7 @@ Function Reference
> vidioc-subdev-g-fmt
> vidioc-subdev-g-frame-interval
> vidioc-subdev-g-selection
> + vidioc-subdev-querycap.rst
.rst looks like extra.
> vidioc-subscribe-event
> func-mmap
> func-munmap
> diff --git a/Documentation/userspace-api/media/v4l/vidioc-subdev-querycap.rst b/Documentation/userspace-api/media/v4l/vidioc-subdev-querycap.rst
> new file mode 100644
> index 000000000000..d9b2e19e1339
> --- /dev/null
> +++ b/Documentation/userspace-api/media/v4l/vidioc-subdev-querycap.rst
> @@ -0,0 +1,114 @@
> +.. Permission is granted to copy, distribute and/or modify this
> +.. document under the terms of the GNU Free Documentation License,
> +.. Version 1.1 or any later version published by the Free Software
> +.. Foundation, with no Invariant Sections, no Front-Cover Texts
> +.. and no Back-Cover Texts. A copy of the license is included at
> +.. Documentation/userspace-api/media/fdl-appendix.rst.
> +..
> +
> +.. _VIDIOC_SUBDEV_QUERYCAP:
> +
> +****************************
> +ioctl VIDIOC_SUBDEV_QUERYCAP
> +****************************
> +
> +Name
> +====
> +
> +VIDIOC_SUBDEV_QUERYCAP - Query sub-device capabilities
> +
> +
> +Synopsis
> +========
> +
> +.. c:function:: int ioctl( int fd, VIDIOC_SUBDEV_QUERYCAP, struct v4l2_subdev_capability *argp )
> + :name: VIDIOC_SUBDEV_QUERYCAP
> +
> +
> +Arguments
> +=========
> +
> +``fd``
> + File descriptor returned by :ref:`open() <func-open>`.
> +
> +``argp``
> + Pointer to struct :c:type:`v4l2_subdev_capability`.
> +
> +
> +Description
> +===========
> +
> +All V4L2 sub-devices support the
> +``VIDIOC_SUBDEV_QUERYCAP`` ioctl. It is used to identify
You could rewrap the paragraph.
> +kernel devices compatible with this specification and to obtain
> +information about driver and hardware capabilities. The ioctl takes a
> +pointer to a struct :c:type:`v4l2_subdev_capability` which is filled by the
> +driver. When the driver is not compatible with this specification the ioctl
> +returns ``ENOTTY`` error code.
> +
> +.. tabularcolumns:: |p{1.5cm}|p{2.5cm}|p{13cm}|
> +
> +.. c:type:: v4l2_subdev_capability
> +
> +.. flat-table:: struct v4l2_subdev_capability
> + :header-rows: 0
> + :stub-columns: 0
> + :widths: 3 4 20
> +
> + * - __u32
> + - ``version``
> + - Version number of the driver.
> +
> + The version reported is provided by the V4L2 subsystem following the
> + kernel numbering scheme. However, it may not always return the same
> + version as the kernel if, for example, a stable or
> + distribution-modified kernel uses the V4L2 stack from a newer kernel.
> +
> + The version number is formatted using the ``KERNEL_VERSION()``
> + macro:
> + * - :cspan:`2`
> +
> + ``#define KERNEL_VERSION(a,b,c) (((a) << 16) + ((b) << 8) + (c))``
> +
> + ``__u32 version = KERNEL_VERSION(0, 8, 1);``
> +
> + ``printf ("Version: %u.%u.%u\\n",``
> +
> + ``(version >> 16) & 0xFF, (version >> 8) & 0xFF, version & 0xFF);``
> + * - __u32
> + - ``subdev_caps``
> + - Sub-device capabilities of the opened device, see
> + :ref:`subdevice-capabilities`.
> +
> +.. tabularcolumns:: |p{6cm}|p{2.2cm}|p{8.8cm}|
> +
> +.. _subdevice-capabilities:
> +
> +.. cssclass:: longtable
> +
> +.. flat-table:: Sub-Device Capabilities Flags
> + :header-rows: 0
> + :stub-columns: 0
> + :widths: 3 1 4
> +
> + * - V4L2_SUBDEV_CAP_RO_SUBDEV
> + - 0x00000001
> + - The sub-device device node is registered in read-only mode.
> + Access to the sub-device ioctls that modify the device state is
> + restricted. Refer to each individual subdevice ioctl documentation
> + for a description of which restrictions apply to a read-only sub-device.
Tabs would be nice. Same below (and above, too).
Acked-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>
> +
> + * - V4L2_SUBDEV_CAP_RW_SUBDEV
> + - 0x00000002
> + - The sub-device device node is registered in read/write mode, all the
> + subdevice ioctls are accessible from userspace.
> +
> +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.
> +
> +ENOTTY
> + The device node is not a V4L2 sub-device.
--
Kind regards,
Sakari Ailus
