diff options
author | Jens Axboe <axboe@kernel.dk> | 2018-02-07 15:54:20 -0700 |
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committer | Jens Axboe <axboe@kernel.dk> | 2018-02-07 15:54:20 -0700 |
commit | 61a695184fcc8f225327206b88320279dd8684af (patch) | |
tree | 6cbda2b0e7de94ebad95072d17cc0aa82c9d8ab3 /drivers/staging/media/imx/TODO | |
parent | 9e05c864993c5442227f83ae1694a737d7a102ed (diff) | |
parent | 581e400ff935d34d95811258586128bf11baef15 (diff) |
Merge branch 'master' into test
* master: (1190 commits)
ASoC: stm32: add of dependency for stm32 drivers
ASoC: mt8173-rt5650: fix child-node lookup
ASoC: dapm: fix debugfs read using path->connected
platform/x86: samsung-laptop: Re-use DEFINE_SHOW_ATTRIBUTE() macro
platform/x86: ideapad-laptop: Re-use DEFINE_SHOW_ATTRIBUTE() macro
platform/x86: dell-laptop: Re-use DEFINE_SHOW_ATTRIBUTE() macro
seq_file: Introduce DEFINE_SHOW_ATTRIBUTE() helper macro
Documentation/sysctl/user.txt: fix typo
MAINTAINERS: update ARM/QUALCOMM SUPPORT patterns
MAINTAINERS: update various PALM patterns
MAINTAINERS: update "ARM/OXNAS platform support" patterns
MAINTAINERS: update Cortina/Gemini patterns
MAINTAINERS: remove ARM/CLKDEV SUPPORT file pattern
MAINTAINERS: remove ANDROID ION pattern
mm: docs: add blank lines to silence sphinx "Unexpected indentation" errors
mm: docs: fix parameter names mismatch
mm: docs: fixup punctuation
pipe: read buffer limits atomically
pipe: simplify round_pipe_size()
pipe: reject F_SETPIPE_SZ with size over UINT_MAX
...
Diffstat (limited to 'drivers/staging/media/imx/TODO')
-rw-r--r-- | drivers/staging/media/imx/TODO | 63 |
1 files changed, 51 insertions, 12 deletions
diff --git a/drivers/staging/media/imx/TODO b/drivers/staging/media/imx/TODO index 0bee3132b26f..9eb7326f3fc6 100644 --- a/drivers/staging/media/imx/TODO +++ b/drivers/staging/media/imx/TODO @@ -1,19 +1,14 @@ -- Clean up and move the ov5642 subdev driver to drivers/media/i2c, or - merge support for OV5642 into drivers/media/i2c/ov5640.c, and create - the binding docs for it. - - The Frame Interval Monitor could be exported to v4l2-core for general use. -- At driver load time, the device-tree node that is the original source - (the "sensor"), is parsed to record its media bus configuration, and - this info is required in imx-media-csi.c to setup the CSI. - Laurent Pinchart argues that instead the CSI subdev should call its - neighbor's g_mbus_config op (which should be propagated if necessary) - to get this info. However Hans Verkuil is planning to remove the - g_mbus_config op. For now this driver uses the parsed DT mbus config - method until this issue is resolved. +- The CSI subdevice parses its nearest upstream neighbor's device-tree + bus config in order to setup the CSI. Laurent Pinchart argues that + instead the CSI subdev should call its neighbor's g_mbus_config op + (which should be propagated if necessary) to get this info. However + Hans Verkuil is planning to remove the g_mbus_config op. For now this + driver uses the parsed DT bus config method until this issue is + resolved. - This media driver supports inheriting V4L2 controls to the video capture devices, from the subdevices in the capture device's @@ -21,3 +16,47 @@ link_notify callback when the pipeline is modified. It should be decided whether this feature is useful enough to make it generally available by exporting to v4l2-core. + +- The OF graph is walked at probe time to form the list of fwnodes to + be passed to v4l2_async_notifier_register(), starting from the IPU + CSI ports. And after all async subdevices have been bound, + v4l2_fwnode_parse_link() is used to form the media links between + the entities discovered by walking the OF graph. + + While this approach allows support for arbitrary OF graphs, there + are some assumptions for this to work: + + 1. All port parent nodes reachable in the graph from the IPU CSI + ports bind to V4L2 async subdevice drivers. + + If a device has mixed-use ports such as video plus audio, the + endpoints from the audio ports are followed to devices that must + bind to V4L2 subdevice drivers, and not for example, to an ALSA + driver or a non-V4L2 media driver. If the device were bound to + such a driver, imx-media would never get an async completion + notification because the device fwnode was added to the async + list, but the driver does not interface with the V4L2 async + framework. + + 2. Every port reachable in the graph is treated as a media pad, + owned by the V4L2 subdevice that is bound to the port's parent. + + This presents problems for devices that don't make this port = pad + assumption. Examples are SMIAPP compatible cameras which define only + a single output port node, but which define multiple pads owned + by multiple subdevices (pixel-array, binner, scaler). Or video + decoders (entity function MEDIA_ENT_F_ATV_DECODER), which also define + only a single output port node, but define multiple pads for video, + VBI, and audio out. + + A workaround at present is to set the port reg properties to + correspond to the media pad index that the port represents. A + possible long-term solution is to implement a subdev API that + maps a port id to a media pad index. + + 3. Every endpoint of a port reachable in the graph is treated as + a media link, between V4L2 subdevices that are bound to the + port parents of the local and remote endpoints. + + Which means a port must not contain mixed-use endpoints, they + must all refer to media links between V4L2 subdevices. |