The CP210x (e.g. CP2105) datasheets mention “Royalty-free" VCP and USBXpress drivers. What does this mean? Are these drivers open source?
"Royalty free" means VCP and USBXpress drivers can be used and distributed at no cost. Silicon Labs collects no fees for driver usage and distribution.
Furthermore, these drivers are not open source, and they only support Silicon Labs devices.