From: Hans Verkuil <hans.verkuil@xxxxxxxxx>
Add documentation for the new VIDIOC_SUBDEV_QUERYCAP ioctl.
Signed-off-by: Hans Verkuil <hans.verkuil@xxxxxxxxx>
---
Documentation/media/uapi/v4l/user-func.rst | 1 +
.../media/uapi/v4l/vidioc-subdev-querycap.rst | 118 +++++++++++++++++++++
2 files changed, 119 insertions(+)
create mode 100644 Documentation/media/uapi/v4l/vidioc-subdev-querycap.rst
diff --git a/Documentation/media/uapi/v4l/user-func.rst b/Documentation/media/uapi/v4l/user-func.rst
index 3e0413b83a33..eda5a01b5228 100644
--- a/Documentation/media/uapi/v4l/user-func.rst
+++ b/Documentation/media/uapi/v4l/user-func.rst
@@ -71,6 +71,7 @@ Function Reference
vidioc-subdev-g-fmt
vidioc-subdev-g-frame-interval
vidioc-subdev-g-selection
+ vidioc-subdev-querycap
vidioc-subscribe-event
func-mmap
func-munmap
diff --git a/Documentation/media/uapi/v4l/vidioc-subdev-querycap.rst b/Documentation/media/uapi/v4l/vidioc-subdev-querycap.rst
new file mode 100644
index 000000000000..e43cdf34bc55
--- /dev/null
+++ b/Documentation/media/uapi/v4l/vidioc-subdev-querycap.rst
@@ -0,0 +1,118 @@
+.. -*- coding: utf-8; mode: 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``
+
+
+Description
+===========
+
+All V4L2 sub-devices support the
+``VIDIOC_SUBDEV_QUERYCAP`` ioctl. It is used to identify
+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
+ - ``device_caps``
+ - Sub-device capabilities of the opened device, see
+ :ref:`subdevice-capabilities`.
+ * - __u32
+ - ``entity_id``
+ - The media controller entity ID of the sub-device. This is only valid if
+ the ``V4L2_SUBDEV_CAP_ENTITY`` capability is set, it is 0 otherwise.
+ * - __u32
+ - ``media_node_major``
+ - The major number of the media controller device node corresponding sub-device.
+ This is only valid if the ``V4L2_SUBDEV_CAP_ENTITY`` capability is set, it is
+ 0 otherwise.
+ * - __u32
+ - ``media_node_minor``
+ - The minor number of the media controller device node corresponding sub-device.
+ This is only valid if the ``V4L2_SUBDEV_CAP_ENTITY`` capability is set, it is
+ 0 otherwise.
+ * - __u32
+ - ``reserved``\ [27]
+ - Reserved for future extensions. Applications and drivers must set
+ the array to zero.
+
+.. 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_ENTITY``
+ - 0x00000001
+ - The sub-device is a media controller entity and the ``entity_id``,
+ ``media_node_major`` and ``media_node_minor`` fields of
+ struct :c:type:`v4l2_subdev_capability` are valid. These fields
+ are 0 if this capability is not set.
+
+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.
--
2.13.1
