/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
 * PPS API kernel header
 *
 * Copyright (C) 2009   Rodolfo Giometti <giometti@linux.it>
 */

#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];            /* symbolic name */
        char path[PPS_MAX_NAME_LEN];            /* path of connected device */
        int mode;                               /* PPS allowed mode */

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

        struct module *owner;
        struct device *dev;             /* Parent device for device_create */
};

struct pps_event_time {
#ifdef CONFIG_NTP_PPS
        struct timespec64 ts_raw;
#endif /* CONFIG_NTP_PPS */
        struct timespec64 ts_real;
};

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

        struct pps_kparams params;              /* PPS 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 */
        unsigned int last_fetched_ev;           /* last fetched PPS event id */
        wait_queue_head_t queue;                /* PPS event queue */

        unsigned int id;                        /* PPS source unique ID */
        void const *lookup_cookie;              /* For pps_lookup_dev() only */
        struct device dev;
        struct fasync_struct *async_queue;      /* fasync method */
        spinlock_t lock;
};

/*
 * Global variables
 */

extern const struct attribute_group *pps_groups[];

/*
 * Internal functions.
 *
 * These are not actually part of the exported API, but this is a
 * convenient header file to put them in.
 */

extern int pps_register_cdev(struct pps_device *pps);
extern void pps_unregister_cdev(struct pps_device *pps);

/*
 * 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 void pps_event(struct pps_device *pps,
                struct pps_event_time *ts, int event, void *data);
/* Look up a pps_device by magic cookie */
struct pps_device *pps_lookup_dev(void const *cookie);

static inline void timespec_to_pps_ktime(struct pps_ktime *kt,
                struct timespec64 ts)
{
        kt->sec = ts.tv_sec;
        kt->nsec = ts.tv_nsec;
}

static inline void pps_get_ts(struct pps_event_time *ts)
{
        struct system_time_snapshot snap;

        ktime_get_snapshot(&snap);
        ts->ts_real = ktime_to_timespec64(snap.real);
#ifdef CONFIG_NTP_PPS
        ts->ts_raw = ktime_to_timespec64(snap.raw);
#endif
}

/* Subtract known time delay from PPS event time(s) */
static inline void pps_sub_ts(struct pps_event_time *ts, struct timespec64 delta)
{
        ts->ts_real = timespec64_sub(ts->ts_real, delta);
#ifdef CONFIG_NTP_PPS
        ts->ts_raw = timespec64_sub(ts->ts_raw, delta);
#endif
}

#endif /* LINUX_PPS_KERNEL_H */