Thank you for your suggestion, TBS6285 is not supported yet. It has si2168 demodulator and si2158 tuner, both are used by another USB card.
I had started to implement it and found it difficult to me. Demodulator code is little bit different and missing functions there.
This is sad, because card looks like good, low power consumption, low profile, 4x tuner.
Maybe you should discuss this card on the linux-media mailing list. It's possible somebody may already be working on drivers there, or may be willing to write them if you provide a sample card.