[Unit]
Description=Synchronize system clock or PTP hardware clock (PHC)
Documentation=man:phc2sys
Requires=ptp4l@%i.service
After=ptp4l@%i.service
Before=time-sync.target

[Service]
Type=simple
ExecStart=@SBINDIR@/phc2sys -w -s %I

[Install]
WantedBy=multi-user.target