Skeleton / Example PCI Device Driver

Hello,

In my slow quest to port/write the VirtualBox Guest Additions, the first step is a driver for the virtual PCI device that handles communication with the VirtualBox host.

Is there a skeleton device driver for PCI devices? My first goal is just the boilerplate init code, attaching to the IRQ and I/O memory, and logging the interrupts as they come in.

If there isn't a skeleton driver, could anyone recommend the simplest example that I could use as a starting point?

Thanks!