HelenOS sources

XHCI_PORT_CEC     122 uspace/drv/bus/usb/xhci/debug.c 	DUMP_REG(port, XHCI_PORT_CEC);
XHCI_PORT_CEC      62 uspace/drv/bus/usb/xhci/rh.c     XHCI_REG_MASK(XHCI_PORT_CEC);
HelenOS homepage, sources at GitHub