Re: [PATCH 1/5] ptp: Added a brand new class driver for ptp clocks.

[Christian Riesch]

Alan Cox wrote:
> > The master node in a PTP network probably takes its time from a
> > precise external time source, like GPS. The GPS provides a 1 PPS
> > directly to the PTP clock hardware, which latches the PTP hardware
> > clock time on the PPS edge. This provides one sample as input to a
> > clock servo (in the PTPd) that, in turn, regulates the PTP clock
> > hardware.
>
> A PTP clock is TAI, Unix time is UTC.

Not necessarily. AFAIK, the time distributed by IEEE1588v2 can either be 
based on the "PTP epoch" (timePropertiesDS.ptpTimescale=TRUE) and thus 
represent TAI or be based on an implementation specific arbitrary epoch 
(timePropertiesDS.ptpTimescale=FALSE) and represent time on some 
arbitrary time scale.

Christian


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