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@xxxxxxxxxxxxxxx> --- Documentation/driver-api/media/camera-sensor.rst | 13 +++++++++++++ 1 file changed, 13 insertions(+) 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. -- 2.27.0
