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author | 2020-10-13 16:02:27 +0200 | |
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committer | 2020-11-16 10:31:15 +0100 | |
commit | 9d0a79e55a626165efb52bb15d714d231fc985e6 (patch) | |
tree | 1d4b981927ae56cdff88dccde01b799d34430d0d /Documentation | |
parent | media: Documentation: v4l: Fix language (diff) | |
download | linux-9d0a79e55a626165efb52bb15d714d231fc985e6.tar.gz linux-9d0a79e55a626165efb52bb15d714d231fc985e6.tar.bz2 linux-9d0a79e55a626165efb52bb15d714d231fc985e6.zip |
media: Documentation: v4l: Document required controls on camera sensors
Raw camera sensors connected to parallel or CSI-2 busses need to implement
V4L2_CID_LINK_FREQ control so receiver drivers can configure the hardware
accordingly.
Document this. Also say V4L2_CID_PIXEL_RATE is recommended for such
hardware.
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Diffstat (limited to 'Documentation')
-rw-r--r-- | Documentation/driver-api/media/camera-sensor.rst | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/Documentation/driver-api/media/camera-sensor.rst b/Documentation/driver-api/media/camera-sensor.rst index 4d1ae12b9b4d..ffb0cad8137a 100644 --- a/Documentation/driver-api/media/camera-sensor.rst +++ b/Documentation/driver-api/media/camera-sensor.rst @@ -132,3 +132,16 @@ used to obtain device's power state after the power state transition: The function returns a non-zero value if it succeeded getting the power count or runtime PM was disabled, in either of which cases the driver may proceed to access the device. + +Controls +-------- + +For camera sensors that are connected to a bus where transmitter and receiver +require common configuration set by drivers, such as CSI-2 or parallel (BT.601 +or BT.656) bus, the ``V4L2_CID_LINK_FREQ`` control is mandatory on transmitter +drivers. Receiver drivers can use the ``V4L2_CID_LINK_FREQ`` to query the +frequency used on the bus. + +The transmitter drivers should also implement ``V4L2_CID_PIXEL_RATE`` control in +order to tell the maximum pixel rate to the receiver. This is required on raw +camera sensors. |