This is an example of a kernel device which works as a parallel port. When writing or reading from the device, it will write in a buffer and print in the KERN_DEBUG.
git clone git@github.com:brunoproduit/my_device.git
cd my_device
make
Note: needs sudo for insmod, mknod & chmod.
The device driver is created in the nodefile /dev/my_device as a character device with major number 42.
The device will write in KERN_DEBUG, which can be read with dmesg.
In order to test you can use:
make test
This will insert the module in the kernel, clean dmesg, run device_usage_example.c and print dmesg.
It is also possible to read with cat /dev/my_device.
make clean
Note: needs sudo for rmmod & rm.