LDT project is useful for Linux driver development beginners and as starting point for a new drivers. The driver uses following Linux facilities: module, platform driver, file operations (read/write, mmap, ioctl, blocking and nonblocking mode, polling), kfifo, completion, interrupt, tasklet, work, kthread, timer, simple misc device, multiple char devices, Device Model, configfs, UART 0x3f8, HW loopback, SW loopback, ftracer.
Just run
git clone --recurse-submodules git://github.com/makelinux/ldt.git && cd ldt && make && ./ldt-test && sudo ./misc_loop_drv_test
and explore sources.
Main source file of LDT: ldt.c
Test script, run it: ldt-test
Generic testing utility for Device I/O: dio.c
Simple misc driver with read, write, fifo, tasklet and IRQ: misc_loop_drv.c
Browse the rest of source: https://github.com/makelinux/ldt/