Some time ago I have written a few real-time Linux drivers for Xenomai and complementary OROCOS components. But first thing first! What the heck is Xenomai and OROCOS? To keep it as short as possible; Xenomai is an open-source project which aim is to bring real-time API to Linux based system. It is an extension to the Linux kernel which makes it a hard real-time operating system. On the other hand, OROCOS is a robotic framework that brings a vast number of libraries and a toolchain to create components. What is more, Xenomai and OROCOS do play along which means you can facilitate features of both i.e. to create a hard real-time components.
If you are interested you can find the code for each driver and for each OROCOS component on my GitHub repository. Feel free to fork!
Below are direct links to the repositories: