How to use Radxa Camera 4k on Rock5A with OpenCv?

I am trying to use a Radxa Camera 4k on my Rock5A with OpenCv.
I can get image with cv2.VideoCapture(11),but I can not controll any parameter.
I want to increase the exposure time. I used to achieve this by decrease frame rate.
Opencv is able to get the fps, but not set.

How can I control fps of the Radxa Camera 4k on my Rock5A?
Any information appretiated.