Is there any C API for Rainbow HAT?
If so, where to finf it?
There might be C libraries for the various components- the lights and touch are just regular IO pins, then there’s the:
- APA102 (basically just a shift register) pixels with some code you could repurpose: https://github.com/pimoroni/blinkt/tree/master/library_c
- BMP280 which has a C driver from the manufacturer, but might take some adapting for the Pi - https://github.com/BoschSensortec/BMP280_driver
- HT16k33 for which there appears to be a kernel module! https://github.com/torvalds/linux/blob/master/drivers/auxdisplay/ht16k33.c