# /etc/systemd/system/phc2sys-gm.service

[Unit]
Description=Synchronize eth0 PHC from GNSS-disciplined system clock
After=ptp4l-gm.service
Requires=ptp4l-gm.service

[Service]
Type=simple
ExecStart=/usr/sbin/phc2sys \
    -s CLOCK_REALTIME \
    -c eth0 \
    -w \
    --step_threshold=0.5 \
    -m
Restart=always
RestartSec=3

[Install]
WantedBy=multi-user.target