Module servo 

PI servo clock discipline for NTP/PTP.

Implements a proportional-integral controller that adjusts system clock frequency to converge the measured offset to zero. The servo operates in three phases:

1. Init – discard the first few samples while filters warm up.
2. FLL (Frequency-Lock Loop) – large gains for fast initial convergence.
3. PLL (Phase-Lock Loop) – small gains for fine-grained tracking.

Structs

PiServo

PI (Proportional-Integral) servo for clock discipline.

ServoConfig

Configuration for the PI servo.

Enums

ServoAction

Action to take on the system clock after processing a sample.

ServoState

Servo operating state.