DTS references and debug notes for GPIO pca9548 - Theoi-Meteoroi/GPIO-pca9548 GitHub Wiki
DTS references and debug notes
https://packages.debian.org/buster/device-tree-compiler
https://github.com/raspberrypi/firmware/tree/master/boot/overlays
https://github.com/raspberrypi/documentation/blob/master/configuration/device-tree.md
sudo vcdbg log msg
https://www.raspberrypi.org/documentation/configuration/device-tree.md