This does the timespec thing, tho' using the dreaded a local temp
rather than a kludgy pointer cast. Since the API is more general
than just PPS,  i changed the softc names too.

Getting close to something we can commit?



Index: sys/dev/ic/com.c
===================================================================
RCS file: /cvsroot/src/sys/dev/ic/com.c,v
retrieving revision 1.143
diff -c -r1.143 com.c
*** com.c	1998/03/22 00:55:37	1.143
--- com.c	1998/04/22 06:11:35
***************
*** 595,600 ****
--- 595,604 ----
  	/* Clear any break condition set with TIOCSBRK. */
  	com_break(sc, 0);
  
+ 	/* Turn off PPS on last close. */
+ 	sc->sc_timestamp_state = PPS_NONE;
+ 	sc->sc_ppsmask = 0;
+ 
  	/*
  	 * Hang up if necessary.  Wait a bit, so the other side has time to
  	 * notice even if we immediately open the port again.
***************
*** 689,694 ****
--- 693,703 ----
  		/* Fetch the current modem control status, needed later. */
  		sc->sc_msr = bus_space_read_1(sc->sc_iot, sc->sc_ioh, com_msr);
  
+ 		/* Clear PPS state on open. */
+ 		sc->sc_ppsmask = 0;
+ 		sc->sc_timestamp_state = PPS_NONE;
+ 		bzero(&sc->sc_pps_timestamp, sizeof(sc->sc_pps_timestamp));
+ 
  		splx(s2);
  
  		/*
***************
*** 933,938 ****
--- 942,999 ----
  		*(int *)data = bits;
  		break;
  	}
+ 
+ 	case TIOCGTSTAMP:
+ 		*(int*) data = sc->sc_timestamp_state;
+ 		break;
+ 
+ 	case TIOCSTSTAMP:
+ 	 	/* 
+ 		 * Compute msr masks from user-specified timestamp state.
+ 		 */
+ 		switch (sc->sc_timestamp_state) {
+ 		case PPS_NONE:
+ 			sc->sc_ppsmask = 0;
+ 			sc->sc_ppsedge = 0;
+ 			break;
+ 	
+ 		case PPS_DCD_LEADING_EDGE:
+ 			sc->sc_ppsedge = MSR_DCD;
+ 			sc->sc_ppsmask = MSR_DCD;
+ 			break;
+ 	
+ 		case PPS_DCD_TRAILING_EDGE:
+ 			sc->sc_ppsedge = 0;
+ 			sc->sc_ppsmask = MSR_DCD;
+ 			break;
+ 	
+ 		default:
+ 			error = EINVAL;
+ 			break;
+ 		}
+ 		sc->sc_timestamp_state = *(int*) data;
+ 		break;
+ 
+ 	case TIOCDCDTIMESTAMP:	/* XXX old, overloaded API */
+ 		/*
+ 		 * Some GPS clocks models use the falling rather than
+ 		 * rising edge as the on-the-second signal. 
+ 		 * The old API has no way to specify PPS polarity.
+ 		 */
+ #ifndef PPS_TRAILING_EDGE
+ 	         sc->sc_ppsedge = MSR_DCD;
+ #else
+ 	         sc->sc_ppsmask = 0;
+ #endif
+ 		sc->sc_ppsedge = MSR_DCD;
+ 		TIMESPEC_TO_TIMEVAL((struct timeval*)data, 
+ 		    &sc->sc_pps_timestamp);
+ 		break;
+ 
+ 	case TIOCTSTAMP:
+ 		*(struct timespec *)data = sc->sc_pps_timestamp;
+ 		break;
+ 
  	default:
  		error = ENOTTY;
  		break;
***************
*** 1749,1754 ****
--- 1810,1831 ----
  		sc->sc_msr = msr;
  		if (ISSET(delta, sc->sc_msr_mask)) {
  			SET(sc->sc_msr_delta, delta);
+ 
+ 			/*
+ 			 * Pulse-per-second clock  signal on edge of DCD?
+ 			 */
+ 			if (ISSET(delta, sc->sc_ppsmask) &&
+ 			    (msr & sc->sc_ppsmask) == sc->sc_ppsedge) {
+ 				struct timeval tv;
+ 
+ 				/* XXX nanotime() */
+ 				microtime(&tv);
+ 				TIMEVAL_TO_TIMESPEC(&tv, 
+ 				    &sc->sc_pps_timestamp);
+ #ifdef PPS_SYNC
+ 				hardpps(&tv, tv.usec);
+ #endif
+ 			}
  
  			/*
  			 * Stop output immediately if we lose the output
Index: sys/dev/ic/comvar.h
===================================================================
RCS file: /cvsroot/src/sys/dev/ic/comvar.h,v
retrieving revision 1.22
diff -c -r1.22 comvar.h
*** comvar.h	1998/02/02 23:01:05	1.22
--- comvar.h	1998/04/22 06:11:35
***************
*** 109,114 ****
--- 109,120 ----
  	void (*disable) __P((struct com_softc *));
  	int enabled;
  
+ 	/* Discipline system clock to pulse-per-second signal wire to DCD? */
+ 	int	sc_timestamp_state;		/* userlevel ioctl state */
+ 	int	sc_ppsmask;			/* pps signal mask */
+ 	int	sc_ppsedge;			/* pps edge mask */
+ 	struct timespec	sc_pps_timestamp;	/* XXX nanotime() */
+ 
  #if NRND > 0 && defined(RND_COM)
  	rndsource_element_t  rnd_source;
  #endif
Index: sys/sys/ttycom.h
===================================================================
RCS file: /cvsroot/src/sys/sys/ttycom.h,v
retrieving revision 1.8
diff -c -r1.8 ttycom.h
*** ttycom.h	1998/03/26 02:45:01	1.8
--- ttycom.h	1998/04/22 06:11:35
***************
*** 129,136 ****
--- 129,146 ----
  #define		TIOCFLAG_CRTSCTS	0x04	/* set crtscts on open */
  #define		TIOCFLAG_MDMBUF		0x08	/* set mdmbuf on open */
  #define		TIOCFLAG_CDTRCTS	0x10	/* set cdtrcts on open */
+ 
  #define	TIOCDCDTIMESTAMP _IOR('t', 88, struct timeval) /* get timestamp of last
  						 * Cd rise, stamp next rise */
+ #define	TIOCGTSTAMP _IOR('t', 82, int)	/* get DCD-PPS timestamp state */
+ #define	TIOCSTSTAMP _IOW('t', 83, int)	/* set DCD-timestamp state */
+ #if !defined(_POSIX_SOURCE) && !defined(_XOPEN_SOURCE)
+ #define PPS_NONE		0
+ #define PPS_DCD_LEADING_EDGE	1
+ #define PPS_DCD_TRAILING_EDGE	2
+ #endif
+ #define	TIOCTSTAMP _IOR('t', 84, struct timespec)
+ 					/* fetch most recent timestamp */
  
  #define	TTYDISC		0		/* termios tty line discipline */
  #define	TABLDISC	3		/* tablet discipline */