Inspired by Strawson about a month ago, I’ve written a library to simplify fast access to the eQEP module. https://github.com/jadedanemone/BBB-eQEP
I took the extremely detailed route, and provided a function for nearly every eQEP feature. Please take a look at it, and help me make it even better/easier!
Note: this library is incompatible with Nathaniel Lewis’ kernel, and will likely require your program to be run with root permissions.
Instead messing with /dev/mem you could write a proper kernel mode driver...
Or you could use the kernel module written by Nathaniel Lewis that is now included in the normal Debian distribution. His approach doesn’t work for my use case, and I’ve seen a number of others attempting to roll their own /dev/mem solutions for speed, all of which enable his module and then ignore it. This library just might make it easier for them.
This is why I wrote a *proper* kernel mode driver.
Please have a look at kernel frameworks like UIO.
Using /dev/mem is in these days _always_ a bad idea.