Tutorials
Creating a read write proc entry in kernel versions above 3.10
proc_create() example for kernel module
Using structures to set the functions
Driver porting: The seq_file interface
Linux.com: Linux Training
The Kernel Newbie Corner: Kernel Debugging Using proc “Sequence” Files–Part 1
KernelNewbies
CrashCourse: An introduction to Linux kernel programming
Lesson 11: Adding “proc” files to your modules — Part 1
The Linux Kernel Module Programming Guide
2005-12-31 ver 2.6.3 for Linux Kernels 2.6.x (2.6.14)
5.3. Manage /proc file with standard filesystem