Contributing to the device driver staging section of the linux tree

Hello, I want to re start the code clean up stuff in the staging branch of drivers in the linux tree. I have done this before some time back on the 2.6 branch. I want to get back to atleast start off again (I am learning developing device drivers) to be active in the community. My question is that the latest linux kernel is 3.x there have been so many versions of it since 2.6. So how to decide which branch we should be working on and which is relevant enought in todays time. Thanks Kashyap Gada gada.kashyap@gmail.com