Function PPSSinkFromDevice

phc/pps_source.go:265–294

PPSSinkFromDevice configures the targetDevice to be a PPS sink and report PPS timestamp events

(targetDevice DeviceController, pinIndex uint)

}

// PPSSinkFromDevice configures the targetDevice to be a PPS sink and report PPS timestamp events
func PPSSinkFromDevice(targetDevice DeviceController, pinIndex uint) (*PPSSink, error) {
	pfd := unix.PollFd{
		Events: unix.POLLIN | unix.POLLPRI,
		Fd:     int32(targetDevice.Fd()),
	}
	ppsSink := PPSSink{
		InputPin:       pinIndex,
		Polarity:       unix.PTP_RISING_EDGE,
		PulseWidth:     defaultPulseWidth,
		Device:         targetDevice,
		pollDescriptor: pfd,
	}

	req := &PtpExttsRequest{
		Flags: unix.PTP_ENABLE_FEATURE | ppsSink.Polarity,
		Index: uint32(ppsSink.InputPin), //nolint:gosec // InputPin is a small pin index that always fits in uint32
	}

	err := targetDevice.setPinFunc(pinIndex, unix.PTP_PF_EXTTS, defaultTs2PhcChannel)
	if err != nil {
		return nil, fmt.Errorf("error setting extts input pin for device %s: %w", targetDevice.File().Name(), err)
	}

	err = targetDevice.extTTSRequest(req)
	if err != nil {
		return nil, fmt.Errorf("error during extts request for device %s: %w", targetDevice.File().Name(), err)
	}

	return &ppsSink, nil
}

// getPPSEventTimestamp reads the first PPS event from the sink file descriptor and returns the timestamp of the event