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 #include <linux/cdev.h>
  26 #include <linux/device.h>
  27 #include <linux/time.h>
  28
  29 /*
  30  * Global defines
  31  */
  32
  33 struct pps_device;
  34
  35 /* The specific PPS source info */
  36 struct 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
  48 struct 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 */
  56 struct 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
  82 extern 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
  91 extern int pps_register_cdev(struct pps_device *pps);
  92 extern void pps_unregister_cdev(struct pps_device *pps);
  93
  94 /*
  95  * Exported functions
  96  */
  97
  98 extern struct pps_device *pps_register_source(
  99                 struct pps_source_info *info, int default_params);
 100 extern void pps_unregister_source(struct pps_device *pps);
 101 extern 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 */
 104 struct pps_device *pps_lookup_dev(void const *cookie);
 105
 106 static 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
 113 static 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) */
 125 static 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 */