Re: [gpsd-dev] RFC 2783

[Greg Troxel]

"Eric S. Raymond" <address@hidden> writes:

> It would be more in harmony with the GPSD way of autoconfiguration to
> jigger it so we can say this:
>
> gpsd -n /dev/ttyUSB0 /dev/pps0
>
> and have GPSD figure out for itself that /dev/pps0 should be treated as 
> a PPS device.
>
> Have a look at serial.c:gpsd_classify() - that's probably where the
> magic should happen, based on either a path match to pps or a kernel
> device major number.

This only works for Linux (and perhaps OpenBSD), though; on FreeBSD and
NetBSD there are no /dev/pps, and one typically does the RFC2783 calls
on the serial port.  It's not clear how that work work with gpio, but
presumably you'd open a gpio device either corresponding  to a pin or
tell a multi-pin device which pin, and then the RFC2783 calls would work
on that device.

It's not clear that anyone would want gpsd to use pps and not serial on
a device that does both.   So perhaps explicit /dev/pps being pps, on
systems where that makes sense, is just fine.

It's also not clear to me if this is intended to associate the PPS
device with the serial reporting (to number the PPS seconds according to
*that serial stream*), or if there's any such association concept
already.

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