Right now, I've been learning about writing device-drivers for linux 3.2 kernel for about 2 months. So far I have been able program simple char drivers that only read and write to a fictitious dev structure like a file, but now I'm moving to more advance concepts. The new material I've learned about includes I/O port manipulation, memory management, and interrupts. I feel that I have a basic understanding of overall driver operation but, there is still so much that I don't know.

My question is this, given that I have the basic theory of how to write a dev-driver for a piece of hardware ... how long would it take to actually develop the skills of writing actual software that companies would want to employ? I plan on getting involved in an open-source project and building a portfolio.

Also what type of beginner drivers could I write for hardware that would best help me develop my skills? I was thinking that taking on a project where I design my own key logger would easy and a good assignment to help me understand how IO ports and interrupts are used. I may want to eventually specialize in writing software for video cards or network devices though these devices seem beyond my understanding at the moment.

Thanks for any help