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author | Linus Torvalds <torvalds@linux-foundation.org> | 2020-06-04 06:59:38 +0300 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-06-04 06:59:38 +0300 |
commit | a98f670e41a99f53acb1fb33cee9c6abbb2e6f23 (patch) | |
tree | f8ae10a4cb91758ad7f9422053753a8c5d0f04dc /Documentation/userspace-api/media/v4l/vidioc-dbg-g-chip-info.rst | |
parent | ee01c4d72adffb7d424535adf630f2955748fa8b (diff) | |
parent | 938b29db3aa9c293c7c1366b16e55e308f1a1ddd (diff) | |
download | linux-a98f670e41a99f53acb1fb33cee9c6abbb2e6f23.tar.xz |
Merge tag 'media/v5.8-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media
Pull media updates from Mauro Carvalho Chehab:
- Media documentation is now split into admin-guide, driver-api and
userspace-api books (a longstanding request from Jon);
- The media Kconfig was reorganized, in order to make easier to select
drivers and their dependencies;
- The testing drivers now has a separate directory;
- added a new driver for Rockchip Video Decoder IP;
- The atomisp staging driver was resurrected. It is meant to work with
4 generations of cameras on Atom-based laptops, tablets and cell
phones. So, it seems worth investing time to cleanup this driver and
making it in good shape.
- Added some V4L2 core ancillary routines to help with h264 codecs;
- Added an ov2740 image sensor driver;
- The si2157 gained support for Analog TV, which, in turn, added
support for some cx231xx and cx23885 boards to also support analog
standards;
- Added some V4L2 controls (V4L2_CID_CAMERA_ORIENTATION and
V4L2_CID_CAMERA_SENSOR_ROTATION) to help identifying where the camera
is located at the device;
- VIDIOC_ENUM_FMT was extended to support MC-centric devices;
- Lots of drivers improvements and cleanups.
* tag 'media/v5.8-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media: (503 commits)
media: Documentation: media: Refer to mbus format documentation from CSI-2 docs
media: s5k5baf: Replace zero-length array with flexible-array
media: i2c: imx219: Drop <linux/clk-provider.h> and <linux/clkdev.h>
media: i2c: Add ov2740 image sensor driver
media: ov8856: Implement sensor module revision identification
media: ov8856: Add devicetree support
media: dt-bindings: ov8856: Document YAML bindings
media: dvb-usb: Add Cinergy S2 PCIe Dual Port support
media: dvbdev: Fix tuner->demod media controller link
media: dt-bindings: phy: phy-rockchip-dphy-rx0: move rockchip dphy rx0 bindings out of staging
media: staging: dt-bindings: phy-rockchip-dphy-rx0: remove non-used reg property
media: atomisp: unify the version for isp2401 a0 and b0 versions
media: atomisp: update TODO with the current data
media: atomisp: adjust some code at sh_css that could be broken
media: atomisp: don't produce errs for ignored IRQs
media: atomisp: print IRQ when debugging
media: atomisp: isp_mmu: don't use kmem_cache
media: atomisp: add a notice about possible leak resources
media: atomisp: disable the dynamic and reserved pools
media: atomisp: turn on camera before setting it
...
Diffstat (limited to 'Documentation/userspace-api/media/v4l/vidioc-dbg-g-chip-info.rst')
-rw-r--r-- | Documentation/userspace-api/media/v4l/vidioc-dbg-g-chip-info.rst | 167 |
1 files changed, 167 insertions, 0 deletions
diff --git a/Documentation/userspace-api/media/v4l/vidioc-dbg-g-chip-info.rst b/Documentation/userspace-api/media/v4l/vidioc-dbg-g-chip-info.rst new file mode 100644 index 000000000000..16078a2d3e3d --- /dev/null +++ b/Documentation/userspace-api/media/v4l/vidioc-dbg-g-chip-info.rst @@ -0,0 +1,167 @@ +.. 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. +.. +.. TODO: replace it to GFDL-1.1-or-later WITH no-invariant-sections + +.. _VIDIOC_DBG_G_CHIP_INFO: + +**************************** +ioctl VIDIOC_DBG_G_CHIP_INFO +**************************** + +Name +==== + +VIDIOC_DBG_G_CHIP_INFO - Identify the chips on a TV card + + +Synopsis +======== + +.. c:function:: int ioctl( int fd, VIDIOC_DBG_G_CHIP_INFO, struct v4l2_dbg_chip_info *argp ) + :name: VIDIOC_DBG_G_CHIP_INFO + + +Arguments +========= + +``fd`` + File descriptor returned by :ref:`open() <func-open>`. + +``argp`` + Pointer to struct :c:type:`v4l2_dbg_chip_info`. + + +Description +=========== + +.. note:: + + This is an :ref:`experimental` interface and may + change in the future. + +For driver debugging purposes this ioctl allows test applications to +query the driver about the chips present on the TV card. Regular +applications must not use it. When you found a chip specific bug, please +contact the linux-media mailing list +(`https://linuxtv.org/lists.php <https://linuxtv.org/lists.php>`__) +so it can be fixed. + +Additionally the Linux kernel must be compiled with the +``CONFIG_VIDEO_ADV_DEBUG`` option to enable this ioctl. + +To query the driver applications must initialize the ``match.type`` and +``match.addr`` or ``match.name`` fields of a struct +:c:type:`v4l2_dbg_chip_info` and call +:ref:`VIDIOC_DBG_G_CHIP_INFO` with a pointer to this structure. On success +the driver stores information about the selected chip in the ``name`` +and ``flags`` fields. + +When ``match.type`` is ``V4L2_CHIP_MATCH_BRIDGE``, ``match.addr`` +selects the nth bridge 'chip' on the TV card. You can enumerate all +chips by starting at zero and incrementing ``match.addr`` by one until +:ref:`VIDIOC_DBG_G_CHIP_INFO` fails with an ``EINVAL`` error code. The number +zero always selects the bridge chip itself, e. g. the chip connected to +the PCI or USB bus. Non-zero numbers identify specific parts of the +bridge chip such as an AC97 register block. + +When ``match.type`` is ``V4L2_CHIP_MATCH_SUBDEV``, ``match.addr`` +selects the nth sub-device. This allows you to enumerate over all +sub-devices. + +On success, the ``name`` field will contain a chip name and the +``flags`` field will contain ``V4L2_CHIP_FL_READABLE`` if the driver +supports reading registers from the device or ``V4L2_CHIP_FL_WRITABLE`` +if the driver supports writing registers to the device. + +We recommended the v4l2-dbg utility over calling this ioctl directly. It +is available from the LinuxTV v4l-dvb repository; see +`https://linuxtv.org/repo/ <https://linuxtv.org/repo/>`__ for access +instructions. + + +.. tabularcolumns:: |p{3.5cm}|p{3.5cm}|p{3.5cm}|p{7.0cm}| + +.. _name-v4l2-dbg-match: + +.. flat-table:: struct v4l2_dbg_match + :header-rows: 0 + :stub-columns: 0 + :widths: 1 1 2 + + * - __u32 + - ``type`` + - See :ref:`name-chip-match-types` for a list of possible types. + * - union { + - (anonymous) + * - __u32 + - ``addr`` + - Match a chip by this number, interpreted according to the ``type`` + field. + * - char + - ``name[32]`` + - Match a chip by this name, interpreted according to the ``type`` + field. Currently unused. + * - } + - + + + +.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}| + +.. c:type:: v4l2_dbg_chip_info + +.. flat-table:: struct v4l2_dbg_chip_info + :header-rows: 0 + :stub-columns: 0 + :widths: 1 1 2 + + * - struct v4l2_dbg_match + - ``match`` + - How to match the chip, see :ref:`name-v4l2-dbg-match`. + * - char + - ``name[32]`` + - The name of the chip. + * - __u32 + - ``flags`` + - Set by the driver. If ``V4L2_CHIP_FL_READABLE`` is set, then the + driver supports reading registers from the device. If + ``V4L2_CHIP_FL_WRITABLE`` is set, then it supports writing + registers. + * - __u32 + - ``reserved[8]`` + - Reserved fields, both application and driver must set these to 0. + + + +.. tabularcolumns:: |p{6.6cm}|p{2.2cm}|p{8.7cm}| + +.. _name-chip-match-types: + +.. flat-table:: Chip Match Types + :header-rows: 0 + :stub-columns: 0 + :widths: 3 1 4 + + * - ``V4L2_CHIP_MATCH_BRIDGE`` + - 0 + - Match the nth chip on the card, zero for the bridge chip. Does not + match sub-devices. + * - ``V4L2_CHIP_MATCH_SUBDEV`` + - 4 + - Match the nth sub-device. + + +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 ``match_type`` is invalid or no device could be matched. |