linuxptp/nullf.c

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/**
* @file nullf.c
* @brief Implements a clock servo that always set the frequency offset to zero.
* @note Copyright (C) 2015 Richard Cochran <richardcochran@gmail.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include <stdlib.h>
#include <math.h>
#include "nullf.h"
#include "print.h"
#include "servo_private.h"
struct nullf_servo {
struct servo servo;
};
static void nullf_destroy(struct servo *servo)
{
struct nullf_servo *s = container_of(servo, struct nullf_servo, servo);
free(s);
}
static double nullf_sample(struct servo *servo, int64_t offset,
uint64_t local_ts, double weight,
enum servo_state *state)
{
if (!offset) {
*state = SERVO_LOCKED;
return 0.0;
}
if ((servo->first_update && servo->first_step_threshold &&
servo->first_step_threshold < llabs(offset)) ||
(servo->step_threshold && servo->step_threshold < llabs(offset))) {
*state = SERVO_JUMP;
} else {
*state = SERVO_UNLOCKED;
}
return 0.0;
}
static void nullf_sync_interval(struct servo *servo, double interval)
{
}
static void nullf_reset(struct servo *servo)
{
}
struct servo *nullf_servo_create(void)
{
struct nullf_servo *s;
s = calloc(1, sizeof(*s));
if (!s)
return NULL;
s->servo.destroy = nullf_destroy;
s->servo.sample = nullf_sample;
s->servo.sync_interval = nullf_sync_interval;
s->servo.reset = nullf_reset;
return &s->servo;
}