DM6446 sensor clock setting?

Hello,

     I have a question about setting sensor clock.

    If I have HD/VD as input, do I need to set any clock rate on DM6446 side to sync. with sensor or I just leave it as a slave since all clock and signals come from sensor side? 

     I also read from data sheet, that CCDC supports 75 MHz sensor clock and may up to 90MHz in turbo mode. Do I need to turn this 90MHz ON or I just let 90MHz clock input into DM6446 and it works automatically?

Thanks

Bell Hsu