Re: [PATCH 1/1] LinuxPPS: Pulse per Second support for Linux

From: Lennart Sorensen
Date: Wed Mar 14 2007 - 11:37:35 EST


Well here is my current version of the refclock_nmea.c.patch for
LinuxPPS. It now uses /dev/gps# for the nmea messages and /dev/pps# for
the PPS device (which in my case is of course the same device). I am
running some more tests on it, but I think it is OK.

--- refclock_nmea.c.ori 2007-03-14 11:24:14.000000000 -0400
+++ refclock_nmea.c 2007-03-14 11:31:04.000000000 -0400
@@ -69,6 +69,7 @@
# define DEVICE "COM%d:" /* COM 1 - 3 supported */
#else
# define DEVICE "/dev/gps%d" /* name of radio device */
+# define PPSDEVICE "/dev/pps%d" /* name of pps device */
#endif
#define SPEED232 B4800 /* uart speed (4800 bps) */
#define PRECISION (-9) /* precision assumed (about 2 ms) */
@@ -79,6 +80,7 @@
#define RANGEGATE 500000 /* range gate (ns) */

#define LENNMEA 75 /* min timecode length */
+#define LENPPS PPS_MAX_NAME_LEN

/*
* Tables to compute the ddd of year form icky dd/mm timecode. Viva la
@@ -99,6 +101,7 @@
pps_params_t pps_params; /* pps parameters */
pps_info_t pps_info; /* last pps data */
pps_handle_t handle; /* pps handlebars */
+ int handle_created; /* pps handle created flag */
#endif /* HAVE_PPSAPI */
};

@@ -147,6 +150,11 @@
register struct nmeaunit *up;
struct refclockproc *pp;
int fd;
+#ifdef PPS_HAVE_FINDPATH
+ char id[LENPPS] = "",
+ path[LENPPS],
+ ppsdevice[LENPPS] = ""; /* just a default device */
+#endif /* PPS_HAVE_FINDPATH */
char device[20];

/*
@@ -238,12 +246,26 @@
* Start the PPSAPI interface if it is there. Default to use
* the assert edge and do not enable the kernel hardpps.
*/
+#ifdef PPS_HAVE_FINDPATH
+ /* Get the PPS source's real name */
+ (void)sprintf(ppsdevice, PPSDEVICE, unit);
+ time_pps_readlink(ppsdevice, LENPPS, path, LENPPS);
+
+ /* Try to find the source */
+ fd = time_pps_findpath(path, LENPPS, id, LENPPS);
+ if (fd < 0) {
+ msyslog(LOG_ERR, "refclock_nmea: cannot find PPS path \"%s\" in the system", path);
+ return (0);
+ }
+ msyslog(LOG_INFO, "refclock_nmea: found PPS source \"%s\" at id #%d on \"%s\"", path, fd, id);
+#endif /* PPS_HAVE_FINDPATH */
if (time_pps_create(fd, &up->handle) < 0) {
- up->handle = 0;
+ up->handle_created = 0;
msyslog(LOG_ERR,
"refclock_nmea: time_pps_create failed: %m");
return (1);
}
+ up->handle_created = ~0;
return(nmea_ppsapi(peer, 0, 0));
#else
return (1);
@@ -265,8 +287,10 @@
pp = peer->procptr;
up = (struct nmeaunit *)pp->unitptr;
#ifdef HAVE_PPSAPI
- if (up->handle != 0)
+ if (up->handle_created) {
time_pps_destroy(up->handle);
+ up->handle_created = 0;
+ }
#endif /* HAVE_PPSAPI */
io_closeclock(&pp->io);
free(up);
@@ -374,7 +398,7 @@
/*
* Convert the timespec nanoseconds field to ntp l_fp units.
*/
- if (up->handle == 0)
+ if (!up->handle_created)
return (0);
timeout.tv_sec = 0;
timeout.tv_nsec = 0;

--
Len Sorensen
-
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