The Tic-Tac-Toe game in C that operates in the user space, while communicating with the kernel space through a Character Device File:

Step 1: Write I2C driver for ssd1306 screen

Step 2: Handle buttons using: + gpio descriptor base (device tree) + IRQ handling (gpio IRQ)

Step 3: Write a TicTacToe game on userspace

Video demo project: https://www.youtube.com/watch?v=TrqDp2n_HKs