[Linuxptp-users] Help to understand the ambiguity with phc2sys options

[Nemo C. <nem...@gm...>]

Hi Experts,

According to the man page of phc2sys, it is used to synchronize 2 or more clocks in the system. May I know what does this mean?

To my understanding, phc2sys is used to synchronize the system clock based on the phc in 2 ways, either by directly reading the phc time periodically, or using the PHC's PPS output as PPS source. So it is always for synchronizing the system clock? I do not understand why 2 or more clocks would be synchronized? Does it mean, there could be multiple system clocks and minimum no. of sys clock is 2?

option -a => I looked at the code, and according to this, it is "autocfg". Can someone please explain the scenario of this autocfg? 
The manpage says - read the "clocks" to synchronize. Does it mean, there can be multiple PHC? 
Can there be one PHC on each port of a system?

Thanks,Nemo