This repo is a demonstration on how to compile and use a kernel driver for the PYNQ v2.4 system. Note that this demo assumes that system has an image.ub file that contains a device tree compiled with symbols, and that the pynq package has the functionality to insert a device tree overlay.
To setup the kernel for compiling Linux Device Drivers run the setup_kernel.sh script. This will unpack the kernel headers on the board and run the make steps necessary to enable drivers to be compiled.
A sample kernel driver, gpio-byu.c, with a Makefile has been provided as a demonstration on how to compile it. To compile the gpio-byu.c kernel driver simply run make.
There are two ways to insert the kernel driver:
The first method is to use the following command:
sudo insmod gpio-byu.ko
This command will insert the gpio-byu driver into the kernel for as long as the board is powered on or until
sudo rmmod gpio-byu
is run. This is useful for development because changes can be made quickly to the kernel driver. Confirmation that these commands worked can be recieved by running lsmod to see if the module was inserted or removed.
The second method is to run
sudo make install
This will insert the kernel driver into the kernel in a way that will persist between power cycles. This is useful once the kernel driver is ready to be deployed into the system.
Once the kernel driver has been inserted, the dtbo_led_demo.ipynb can be run to demonstrate inserting a device tree overlay that uses the newly inserted driver to blink the leds on the board.