This is a driver for the DS3231 RTC Chip.
This repository contains code that was written for a university assignment. It is a simple linux device driver for the DS3231 real-time-clock. The target hardware
was a Raspberry Pi 3 Model B v1.1 (revision code a01041) using Raspbian 8 (jesse) with Linux Kernel version 4.9.30-v7+.
It suports reading the time from the chip (cat /dev/ds3231) in the format DD. M hh:mm:ss YYYY (month names are german currently). It also supports writing the current time to the RTC by writing a date of format YYYY-MM-DD hh:mm:ss to /dev/ds3231.
To compile this code you will need a working C compiler and the linux kernel source
tree (typically located at /lib/modules/$(shell uname -r)/build). The kernel source tree can be installed with sudo apt install linux-headers. After that simply open a terminal in the Driver directory and type make. When the compilation finishes you can load the module using sudo insmod ds3231_drv.ko. To check if everything was loaded correctly you can examine the kernel message buffer with dmesg | tail -n 10. You should see something like this:
[82903.900727] ds3231: initializing hardware ...
[82903.902979] ds3231: setting up RTC ...
[82903.904416] ds3231: reset oscillator stop flag (oscillator was stopped).
[82903.905127] ds3231: hardware initialization completed.