Hi Jacopo, Maybe, I miss spoke when I mentioned a helper I did not intent a framework level generic function. Just a function to help in this case :) That being said, I re-read the thread you mentioned. And as Hughes pointed out dynamically generating a "working" link frequency value which can be used by a CSI2 receiver to properly configure its PHY is not trivial. When I created this patch, I also had another to add V4L2_CID_LINK_FREQ support. I am testing this against the TI CAL CSI2 receiver, which already uses the V4L2_CID_PIXEL_RATE value for that purpose, so I also had a patch to add support for V4L2_CID_LINK_FREQ to that driver as well. Unfortunately, similar to Hughes' findings I was not able to make it "work" with all supported resolution/framerate. Unlike my V4L2_CID_PIXEL_RATE solution which now works in all mode with the same receiver. So long story short I dropped the V4L2_CID_LINK_FREQ patch and focused on V4L2_CID_PIXEL_RATE instead. Regard, Benoit Jacopo Mondi <jacopo@xxxxxxxxxx> wrote on Wed [2019-Oct-02 09:59:51 +0200]: > Hi Benoit, > +Hugues > > If you're considering an helper, this thread might be useful to you: > https://patchwork.kernel.org/patch/11019673/ > > Thanks > j >