search for and evaluate I2C hard macros
documented at http://libre-riscv.org/shakti/m_class/I2S/
talking to rudolf from asics.ws, searching specification and clarification on I2S multi-channel http://www.ti.com/lit/an/snla221/snla221.pdf https://www.sparkfun.com/datasheets/BreakoutBoards/I2SBUS.pdf