This project originally started as a project about aggregating device drivers from different sources for various chinese arduino compatible hardware modules and putting them in one place. I have combined work from Davide Gironi who wrote original implementations of several of the drivers (see source code). I liked Davide's implementaitons particularly because, in contrast to a lot of other arduino code, his C code has been written in a highly object oriented fashion which made it easy to integrate his drivers and make them work in a generic fashion.
I have also written several drivers myself and generally the project eventually evolved (2015) into a research project on how to use Adam Dunkels protothreads to create low footprint library with many standard device drivers. Unfortunately I have come to the conclusion that protothreads were horrible choice of design to use for generic device drivers (even though they can be useful for actual applications). So I have eventually just settled for using a FreeRTOS based scheduler in libk and just making the code in the device driver layer work properly when several independent threads access it concurrently. This approach has worked a lot better and libk now has examples supporting mutlithreaded execution on as small devices as the 8-bit avr microcontrollers (used for instance in arduino).
This project is a work in progress and I still occasionally continue work on it whenever a new project comes about where it can be useful.
Libk/MartinK firmware library is distributed under the GNU General Public License V3.