Some Questions from a noobie v4l driver developer

Hi all!

Currently i try to write a driver for a "Technisat Skysat2 HD eXpress" DVB-S2 card. My current module is able to register the pci device and unload. And now begins the journey to v4l ;)

As there is no driver available for linux i decided to write it myself.

Subdevice IDs: 1ae4:0700

My device contains the folowing ics:
SAA7160 rev3 (PCIe Bridge)
STV0903B (decoder)
STV6110A (tuner)

For the two frontends STV0903B and the tuner STV6110A exists already driver. I dived a little through the linux kernel code and found the driver for the "Technisat DVB-S/S2 USB 2.0 device" (from Patrick Boettcher) which contains the same chips except the pcie bridge.

I read in the documentation of the linux kernel (Debian Wheezy - kernel 3.0.0), that v4l(1) was droped in 2.6.37 and new drivers should use v4l2. The documentation of video4linux2 in the linux kernel shows that there is a important function where all "ops" are registered. v4l2_subdev_init(). In my "reference" driver (technisat-usb2.c for the technisat usb device) that function is not used. Patrick Boettcher speeks of a DVB-USB framework on his homepage(http://www.wi-bw.tfh-wildau.de/~pboettch/home/index.php).

So my questions are:
a) What framework should i use? V4L2?
b) Is it reasonable that i could refactor most of the code of Patrick Boettchers Technisat USB Driver?
c) Is the documentation for video4linux2 uptodate in the kernel? Or should i use an other documentation?
d) There is a driver namned saa716x from Manu Abrahams. Is this driver in state where i could modify it that it supports my device?

Best Regards
Georg Gast