I am quite new to RIOT, and, as a robot developper, I searched for hardware-managed quadratic encoders. Didn't found.
I think is would be great to add this kind of API to "periph". I have experience in STM32F4 encoders, and I can help to implement at least for this microcontroller family.
I'm not sure, but is this quadratic encoder the same thing as "rotary encoder" ?
If so, I have a simple driver working. If not, then sorry for the noise.
I think it is the same. And I made a mistake, it is not called "quadratic encoder", but "quadrature encoder", or "rotary encoder", as you said.
Is your driver in the repository ?
Sorry, busy days. My code is at work so it will have to wait until monday.
Current code is really not in a state that can be merged as it's integrated in a prototype application (no API, everything still working with globals...).
But I'll push a WIP PR on monday !