I'm trying to set up time synchronization using PTP (Precision Time Protocol) between my local computer and a hardware device that supports PTP. My computer gets its time via NTP from the internet; and I want to pass this time to the hardware device via PTP. The goal is to have the correct "world time" (within a few 100 msec) on the hardware device.
I have tried to set up ptp4l on my local computer, on Ubuntu 20.04. But so far I don't even know if it is sending out the correct world time (seconds since 1970, or something like that?) to the hardware device. And I have very little information from the hardware device itself: it doesn't work as expected, but I don't know why.
Therefore: how can I see which absolute time (i.e. world time) the ptp4l server is sending out over network to the hardware device? Is there a pmc GET ... command to show this?
Or am I misunderstanding PTP here at all?