include/linux/pps_kernel.h

   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
  34 struct pps_device;
  35
  36 /* The specific PPS source info */
  37 struct 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
  49 struct 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 */
  57 struct 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
  83 extern 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
  92 extern int pps_register_cdev(struct pps_device *pps);
  93 extern void pps_unregister_cdev(struct pps_device *pps);
  94
  95 /*
  96  * Exported functions
  97  */
  98
  99 extern struct pps_device *pps_register_source(
 100                 struct pps_source_info *info, int default_params);
 101 extern void pps_unregister_source(struct pps_device *pps);
 102 extern 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 */
 105 struct pps_device *pps_lookup_dev(void const *cookie);
 106
 107 static 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
 114 static 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) */
 126 static 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