> If you don't want/need to call the baro_event function, it would probably make more sense to make a new baro_board chibios wrapper for the ms5611 peripheral instead of using the existing one calling ms5611_spi_event from baro_event and the convenience function ms5611_spi_periodic from baro_periodic.

I can do that if you think it is a preferred way.

> We should try to not add #ifdefs and workarounds for different architectures to the arch independent part of the peripherals. 

I do keep it in mind and trying to keep these ifdefs on minimal level, but afaik it is not feasible (some defines are necessary for example in https://github.com/podhrmic/paparazzi/blob/rt_paparazzi/sw/airborne/mcu_periph/uart.h#L84 or https://github.com/podhrmic/paparazzi/blob/rt_paparazzi/sw/airborne/subsystems/gps.h#L49 - defining threads, mutexes and some extra stuff)