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#include <linux/cdev.h>
  26#include <linux/device.h>
  27#include <linux/time.h>
  28
  29/*
  30 * Global defines
  31 */
  32
  33struct pps_device;
  34
  35/* The specific PPS source info */
  36struct pps_source_info {
  37        char name[PPS_MAX_NAME_LEN];            /* symbolic name */
  38        char path[PPS_MAX_NAME_LEN];            /* path of connected device */
  39        int mode;                               /* PPS allowed mode */
  40
  41        void (*echo)(struct pps_device *pps,
  42                        int event, void *data); /* PPS echo function */
  43
  44        struct module *owner;
  45        struct device *dev;             /* Parent device for device_create */
  46};
  47
  48struct pps_event_time {
  49#ifdef CONFIG_NTP_PPS
  50        struct timespec64 ts_raw;
  51#endif /* CONFIG_NTP_PPS */
  52        struct timespec64 ts_real;
  53};
  54
  55/* The main struct */
  56struct pps_device {
  57        struct pps_source_info info;            /* PSS source info */
  58
  59        struct pps_kparams params;              /* PPS current params */
  60
  61        __u32 assert_sequence;                  /* PPS assert event seq # */
  62        __u32 clear_sequence;                   /* PPS clear event seq # */
  63        struct pps_ktime assert_tu;
  64        struct pps_ktime clear_tu;
  65        int current_mode;                       /* PPS mode at event time */
  66
  67        unsigned int last_ev;                   /* last PPS event id */
  68        wait_queue_head_t queue;                /* PPS event queue */
  69
  70        unsigned int id;                        /* PPS source unique ID */
  71        void const *lookup_cookie;              /* For pps_lookup_dev() only */
  72        struct cdev cdev;
  73        struct device *dev;
  74        struct fasync_struct *async_queue;      /* fasync method */
  75        spinlock_t lock;
  76};
  77
  78/*
  79 * Global variables
  80 */
  81
  82extern const struct attribute_group *pps_groups[];
  83
  84/*
  85 * Internal functions.
  86 *
  87 * These are not actually part of the exported API, but this is a
  88 * convenient header file to put them in.
  89 */
  90
  91extern int pps_register_cdev(struct pps_device *pps);
  92extern void pps_unregister_cdev(struct pps_device *pps);
  93
  94/*
  95 * Exported functions
  96 */
  97
  98extern struct pps_device *pps_register_source(
  99                struct pps_source_info *info, int default_params);
 100extern void pps_unregister_source(struct pps_device *pps);
 101extern void pps_event(struct pps_device *pps,
 102                struct pps_event_time *ts, int event, void *data);
 103/* Look up a pps_device by magic cookie */
 104struct pps_device *pps_lookup_dev(void const *cookie);
 105
 106static inline void timespec_to_pps_ktime(struct pps_ktime *kt,
 107                struct timespec64 ts)
 108{
 109        kt->sec = ts.tv_sec;
 110        kt->nsec = ts.tv_nsec;
 111}
 112
 113static inline void pps_get_ts(struct pps_event_time *ts)
 114{
 115        struct system_time_snapshot snap;
 116
 117        ktime_get_snapshot(&snap);
 118        ts->ts_real = ktime_to_timespec64(snap.real);
 119#ifdef CONFIG_NTP_PPS
 120        ts->ts_raw = ktime_to_timespec64(snap.raw);
 121#endif
 122}
 123
 124/* Subtract known time delay from PPS event time(s) */
 125static inline void pps_sub_ts(struct pps_event_time *ts, struct timespec64 delta)
 126{
 127        ts->ts_real = timespec64_sub(ts->ts_real, delta);
 128#ifdef CONFIG_NTP_PPS
 129        ts->ts_raw = timespec64_sub(ts->ts_raw, delta);
 130#endif
 131}
 132
 133#endif /* LINUX_PPS_KERNEL_H */
 134