TouchRacer (the original one, by thelv) is a combination of an Android app and a Windows app that lets you turn your smartphone into a steering wheel for playing racing games. This app is the GNU/Linux equivalent/replacement for the original Windows app.
Downloading and Running the GNU/Linux App
Click Here To Download The GNU/Linux App (latest version is 20200423).
There is no installer. Just extract the files and run TouchRacerLinux (for the gui version) or TouchRacerLinux-cli (for the console version). You may have to run it as root.
sudo ./TouchRacerLinux
You will need to install the original Android app in your phone, and run this one in your GNU/Linux system. Both apps will communicate over wifi network, and the system will see the phone as if it were a joystick. You should be able to control any game that has joystick support.
About...
Original idea, Windows and Android apps, name and icon, by thelv (https://touchracer.com/). GNU/Linux app by Pablo Novara.
GNU/Linux app is distributed under the terms of GPLv3 licence. You can download source code here.