PTP and IEEE-1588 hardware timestamping on the Raspberry Pi CM4
I've been following the issue CM4 is missing IEEE1588-2008 support through BCM54210PE since I heard about IEEE1588-2008 support on the Compute Module 4 last year.
Apparently the little NIC included on every Compute Module 4—the BCM54210PE, which is different than the NIC on the Pi 4 model B (a BCM54213PE)—includes support for a feature called PTP, or Precision Time Protocol.