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authorLinus Torvalds <torvalds@linux-foundation.org>2020-06-04 06:59:38 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2020-06-04 06:59:38 +0300
commita98f670e41a99f53acb1fb33cee9c6abbb2e6f23 (patch)
treef8ae10a4cb91758ad7f9422053753a8c5d0f04dc /Documentation/userspace-api/media/v4l/vidioc-dbg-g-chip-info.rst
parentee01c4d72adffb7d424535adf630f2955748fa8b (diff)
parent938b29db3aa9c293c7c1366b16e55e308f1a1ddd (diff)
downloadlinux-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 ...
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+.. 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.