I read in Kernel Trap an email from Greg Kroah-Hartman announcing the release of the Linux Device Driver Kit. It’s a cd-rom iso with a kernel, docbook kernel documentation in easy-browsing format, and the book “Linux Device Drivers”, third edition, by Corbet, Rubini and Kroah-Hartman, published by O’Reilly. All contents licensed under GPL.
You can download the image at kernel.org