How to reverse engineer a PCI-Express driver under Linux ?

[Tomek LECOCQ]

Hello,

I have a PCI-Express video capture card that has a proprietary driver for Linux.
I have some experience with programming in C, and so I would like to start a hobby project to develop a free/libre driver for this device for Linux.
Of course I don’t have access to any documentation about how to communicate with this device, so I think I will need to reverse-engineer the way the existing driver communicates with the hardware. How could I achieve this ?
Also, the long term goal of this project would be to have this driver merged into mainline, so what is allowed or not while doing this to avoid problematic legal ramifications ?
Thank you for your help.

Best regards.
Tomek Lecocq