Is there documentation on exactly how the GPIO is being used in the i/o expander module of the case? I would prefer not to have to reverse engineer this, I’m using a different operating system so cannot use the premade linux software. In my application I also need to use GPIO for my own devices connected to the pass through from the extender so need to understand which pins and settings are being used by the extender itself, such as for RGB and fan control.
Ah, I finally found it at IO Expander — SunFounder Pironman 5 documentation
Please check the documentation first. If you encounter any issues during testing later, feel free to ask for help.