pps_kernel.h

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/*
 * PPS API kernel header
 *
 * Copyright (C) 2009   Rodolfo Giometti <[email protected]>
 *
 *   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., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#ifndef LINUX_PPS_KERNEL_H
#define LINUX_PPS_KERNEL_H

#include <linux/pps.h>

#include <linux/cdev.h>
#include <linux/device.h>
#include <linux/time.h>

/*
 * Global defines
 */

struct pps_device;

/* The specific PPS source info */
struct pps_source_info {
    char name[PPS_MAX_NAME_LEN];        /* simbolic name */
    char path[PPS_MAX_NAME_LEN];        /* path of connected device */
    int mode;               /* PPS's allowed mode */

    void (*echo)(struct pps_device *pps,
            int event, void *data); /* PPS echo function */

    struct module *owner;
    struct device *dev;
};

struct pps_event_time {
#ifdef CONFIG_NTP_PPS
    struct timespec ts_raw;
#endif /* CONFIG_NTP_PPS */
    struct timespec ts_real;
};

/* The main struct */
struct pps_device {
    struct pps_source_info info;        /* PSS source info */

    struct pps_kparams params;      /* PPS's current params */

    __u32 assert_sequence;          /* PPS' assert event seq # */
    __u32 clear_sequence;           /* PPS' clear event seq # */
    struct pps_ktime assert_tu;
    struct pps_ktime clear_tu;
    int current_mode;           /* PPS mode at event time */

    unsigned int last_ev;           /* last PPS event id */
    wait_queue_head_t queue;        /* PPS event queue */

    unsigned int id;            /* PPS source unique ID */
    struct cdev cdev;
    struct device *dev;
    struct fasync_struct *async_queue;  /* fasync method */
    spinlock_t lock;
};

/*
 * Global variables
 */

extern struct device_attribute pps_attrs[];

/*
 * Exported functions
 */

extern struct pps_device *pps_register_source(
        struct pps_source_info *info, int default_params);
extern void pps_unregister_source(struct pps_device *pps);
extern int pps_register_cdev(struct pps_device *pps);
extern void pps_unregister_cdev(struct pps_device *pps);
extern void pps_event(struct pps_device *pps,
        struct pps_event_time *ts, int event, void *data);

static inline void timespec_to_pps_ktime(struct pps_ktime *kt,
        struct timespec ts)
{
    kt->sec = ts.tv_sec;
    kt->nsec = ts.tv_nsec;
}

#ifdef CONFIG_NTP_PPS

static inline void pps_get_ts(struct pps_event_time *ts)
{
    getnstime_raw_and_real(&ts->ts_raw, &ts->ts_real);
}

#else /* CONFIG_NTP_PPS */

static inline void pps_get_ts(struct pps_event_time *ts)
{
    getnstimeofday(&ts->ts_real);
}

#endif /* CONFIG_NTP_PPS */

/* Subtract known time delay from PPS event time(s) */
static inline void pps_sub_ts(struct pps_event_time *ts, struct timespec delta)
{
    ts->ts_real = timespec_sub(ts->ts_real, delta);
#ifdef CONFIG_NTP_PPS
    ts->ts_raw = timespec_sub(ts->ts_raw, delta);
#endif
}

#endif /* LINUX_PPS_KERNEL_H */