Ha ha "scull" ringed a bell and after taking a look at the cover of the book you mention (it's not in the pdf you provide but can be found if you search for ima

Ha ha "scull" ringed a bell and after taking a look at the cover of the book you mention (it's not in the pdf you provide but can be found if you search for images for Linux Device Drivers oreilly) and see the horse ... I totally remembered the book! It was one of the refereces I used while implementing the module and it was a really good and comprehensive book - totally agree with the recommendation :)