[LinuxPPS] refclock_nmea patch

[Udo van den Heuvel]

Rodolfo Giometti wrote:
>> Yes, but now what if we have a device with one /dev/bla giving NMEA and
>> another /dev/duh giving PPS?
>> How is the first /dev/bla passed on to ntpd?
>> I don't get this yet.
>>
>> In my own situation we have NMEA and PPS on teh same RS232 port.
>> I then expect the first link that I apss to LinuxPPS to be used, which
>> isn't.
> 
> The first (or main) device is the GPS data source (/dev/ttyS0 in your
> case) which __could__ be also a PPS data source. 

In my case it is, but PPS is not taken from there.

>>>> Maybe this can help:
>>>> When is the /dev entry (pps0) created?
>>>> Based on what input?
>>> If you have udev when the pps device is created, otherwise you have to
>>> create it by yourself by using mknod.
>> It was there, so udev works I guess.
>> How is decided what port is to be created?
> 
> The system decides the PPS id just the ethernet devices.

But why not for /dev/ttyS1? S2? etc?

>> I once had a /dev/gps0 and /dev/pps0 pointing to /dev/ttyS0.
>> /dev/pps0 was replaced by the new device entry.
>> Why?
> 
> No you should have:
> 
> 	/dev/gps0 -->	/dev/ttyS0
> 	/dev/pps0

I have this.

>> /*
>>  * nmea_start - open the GPS devices and initialize data for processing
>>  */
>> static int
>> nmea_start(
>>         int unit,
>>         struct peer *peer
>>         )
>> {
>>         register struct nmeaunit *up;
>>         struct refclockproc *pp;
>>         int fd;
>>         char device[20];
>>
>>         /*
>>          * Open serial port. Use CLK line discipline, if available.
>>          */
>>         (void)sprintf(device, DEVICE, unit);
>>
>>         fd = refclock_open(device, SPEED232, LDISC_CLK);
>>         if (fd <= 0) {
>> #ifdef HAVE_READLINK
>> (nmead stuff cut)
>> #endif
>>         }
>>
>>         /*
>>          * Allocate and initialize unit structure
>>          */
>>         up = (struct nmeaunit *)emalloc(sizeof(struct nmeaunit));
>>         if (up == NULL) {
>>                 (void) close(fd);
>>                 return (0);
>>         }
>>         memset((char *)up, 0, sizeof(struct nmeaunit));
>>         pp = peer->procptr;
>>         pp->io.clock_recv = nmea_receive;
>>         pp->io.srcclock = (caddr_t)peer;
>>         pp->io.datalen = 0;
>>         pp->io.fd = fd;
> 
> Here the fs is saved, so everything is ok.

So maybe we should make the msyslog messages more clear that the open of
the NMEA source went OK?

> 
> Good! It's ok.
> 

But not clear enough.

BIG issue:

Also it is strange that PPS is not taken from /dev/gps0.
The time_pps_create fails, why?


Udo