Upstream systemd udev rules now set "clock" group for /dev/ptp* and /dev/rtc* devices:
https://github.com/systemd/systemd/commit/af96ccfc24bc4803078a46b4ef2cdeb5decdfbcd

This will enable ptp4l and other applications from the linuxptp package to run without root privileges.

Please considering adding the clock group to the setup package. I think that will be needed by the systemd package when the udev rules are updated.