LXR linux/include/linux/pps

   1/*
   2 * PPS API kernel header
   3 *
   4 * Copyright (C) 2009   Rodolfo Giometti <giometti@linux.it>
   5 *
   6 *   This program is free software; you can redistribute it and/or modify
   7 *   it under the terms of the GNU General Public License as published by
   8 *   the Free Software Foundation; either version 2 of the License, or
   9 *   (at your option) any later version.
  10 *
  11 *   This program is distributed in the hope that it will be useful,
  12 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 *   GNU General Public License for more details.
  15 *
  16 *   You should have received a copy of the GNU General Public License
  17 *   along with this program; if not, write to the Free Software
  18 *   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  19 */
  20
  21#ifndef LINUX_PPS_KERNEL_H
  22#define LINUX_PPS_KERNEL_H
  23
  24#include <linux/pps.h>
  25
  26#include <linux/cdev.h>
  27#include <linux/device.h>
  28#include <linux/time.h>
  29
  30/*
  31 * Global defines
  32 */
  33
  34struct pps_device;
  35
  36/* The specific PPS source info */
  37struct pps_source_info {
  38        char name[PPS_MAX_NAME_LEN];            /* simbolic name */
  39        char path[PPS_MAX_NAME_LEN];            /* path of connected device */
  40        int mode;                               /* PPS's allowed mode */
  41
  42        void (*echo)(struct pps_device *pps,
  43                        int event, void *data); /* PPS echo function */
  44
  45        struct module *owner;
  46        struct device *dev;             /* Parent device for device_create */
  47};
  48
  49struct pps_event_time {
  50#ifdef CONFIG_NTP_PPS
  51        struct timespec64 ts_raw;
  52#endif /* CONFIG_NTP_PPS */
  53        struct timespec64 ts_real;
  54};
  55
  56/* The main struct */
  57struct pps_device {
  58        struct pps_source_info info;            /* PSS source info */
  59
  60        struct pps_kparams params;              /* PPS's current params */
  61
  62        __u32 assert_sequence;                  /* PPS' assert event seq # */
  63        __u32 clear_sequence;                   /* PPS' clear event seq # */
  64        struct pps_ktime assert_tu;
  65        struct pps_ktime clear_tu;
  66        int current_mode;                       /* PPS mode at event time */
  67
  68        unsigned int last_ev;                   /* last PPS event id */
  69        wait_queue_head_t queue;                /* PPS event queue */
  70
  71        unsigned int id;                        /* PPS source unique ID */
  72        void const *lookup_cookie;              /* pps_lookup_dev only */
  73        struct cdev cdev;
  74        struct device *dev;
  75        struct fasync_struct *async_queue;      /* fasync method */
  76        spinlock_t lock;
  77};
  78
  79/*
  80 * Global variables
  81 */
  82
  83extern const struct attribute_group *pps_groups[];
  84
  85/*
  86 * Internal functions.
  87 *
  88 * These are not actually part of the exported API, but this is a
  89 * convenient header file to put them in.
  90 */
  91
  92extern int pps_register_cdev(struct pps_device *pps);
  93extern void pps_unregister_cdev(struct pps_device *pps);
  94
  95/*
  96 * Exported functions
  97 */
  98
  99extern struct pps_device *pps_register_source(
 100                struct pps_source_info *info, int default_params);
 101extern void pps_unregister_source(struct pps_device *pps);
 102extern void pps_event(struct pps_device *pps,
 103                struct pps_event_time *ts, int event, void *data);
 104/* Look up a pps device by magic cookie */
 105struct pps_device *pps_lookup_dev(void const *cookie);
 106
 107static inline void timespec_to_pps_ktime(struct pps_ktime *kt,
 108                struct timespec64 ts)
 109{
 110        kt->sec = ts.tv_sec;
 111        kt->nsec = ts.tv_nsec;
 112}
 113
 114static inline void pps_get_ts(struct pps_event_time *ts)
 115{
 116        struct system_time_snapshot snap;
 117
 118        ktime_get_snapshot(&snap);
 119        ts->ts_real = ktime_to_timespec64(snap.real);
 120#ifdef CONFIG_NTP_PPS
 121        ts->ts_raw = ktime_to_timespec64(snap.raw);
 122#endif
 123}
 124
 125/* Subtract known time delay from PPS event time(s) */
 126static inline void pps_sub_ts(struct pps_event_time *ts, struct timespec64 delta)
 127{
 128        ts->ts_real = timespec64_sub(ts->ts_real, delta);
 129#ifdef CONFIG_NTP_PPS
 130        ts->ts_raw = timespec64_sub(ts->ts_raw, delta);
 131#endif
 132}
 133
 134#endif /* LINUX_PPS_KERNEL_H */
 135
 136