HelenOS sources

root/uspace/lib/drv/include/

[..]
ahci_iface.h audio_mixer_iface.h audio_pcm_iface.h battery_iface.h ddf/
dev_iface.h ieee80211_iface.h nic_iface.h ops/ pci_dev_iface.h
usb_iface.h usbdiag_iface.h usbhc_iface.h usbhid_iface.h
[..]
HelenOS homepage, sources at GitHub