- ptp_hw: ptp_hw_adj_freq() (ETH_MAC_ESP_CMD_ADJ_PTP_TIME, absolute ppb
vs nominal, clamped +-500 ppm, retried while the addend update is
busy) and ptp_hw_step() (read + write time).
- ptp_clock: first Sync after a GM is selected seeds the integral with
the measured rate and steps the clock; then linuxptp-style PI (kp/ki
from the Sync interval: 0.7/0.3 at 1 s). Re-step above 1 ms. Locked
after 8 Syncs with |offset| < 1 us, unlocked after 3 above; GM change
or loss unlocks and keeps the frequency (holdover).
- Verified vs ptp4l: stepped to GM time, locked after ~19 s; locked
offset within +-510 ns (mostly < 300 ns), correction +39.9 ppm
(crystal -39.8 ppm), path delay ~10.2 us.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
bsncubed
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