[Linuxptp-users] Dynamically sync clocks with phc2sys depending on master/slave

[Peter B. <pe...@be...>]

Hi,

I'm currently working on a network product using gPTP configuration for 
PTP sync. The device shall be a AVB endpoint handling audio and 
according to Avnu specifications all endpoint shall be capable of being 
master on the network. Some plugins for AVB (such as gstreamer and 
alsa-plugins) require that system time (CLOCK_REALTIME) is in sync with 
PHC to get correct timing. I see different cases depending on if the 
device is master or slave. If the device is slave I would like to sync 
PHC to CLOCK_REALTIME. The other way around, if device is master I would 
like to sync CLOCK_REALTIME to PHC.

To the question; is there a way to use phc2sys and handle this 
automatically?

What I currently do manually is (linuxptp version 3.1):

   $ ptp4l -i eth1 -f /etc/linuxptp/gPTP.cfg

On the device becoming master:

   $ phc2sys -c eth1 -s CLOCK_REALTIME --step_threshold=1 
--transportSpecific=1 -w

On the device becoming slave:

   $ phc2sys -c CLOCK_REALTIME -s eth1 --step_threshold=1 
--transportSpecific=1 -w

It would be good if the above could be dynamic. Starting everything as 
services and let the system sync itself.

/Peter