The first thing I would do is check if you can find a BSD driver, it will be much closer to Solaris that Linux. It's usually a lot of work to port drivers from Linux to Solaris and you need to know the driver systems and how to program them for both to make it work.
Be also aware that the so called viral GPL license Linux drivers use forbids you to redistribute any Solaris porting work you do .
If a BSD drivers exists, there are no legal issues porting it.
I would suggest the best resources would be in the discussions on opensolaris.org, I think, without checking that the correct group would be drivers-discuss or driver-discuss ( I can't remember if there is an 's' ) The guys there have loads of experience and resources to get you started and you never know, someone else may have done some of what you need or something very similar.