drivers/pps/clients/pps-ktimer.c

   1 /*
   2  * pps-ktimer.c -- kernel timer test client
   3  *
   4  *
   5  * Copyright (C) 2005-2006   Rodolfo Giometti <giometti@linux.it>
   6  *
   7  *   This program is free software; you can redistribute it and/or modify
   8  *   it under the terms of the GNU General Public License as published by
   9  *   the Free Software Foundation; either version 2 of the License, or
  10  *   (at your option) any later version.
  11  *
  12  *   This program is distributed in the hope that it will be useful,
  13  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  *   GNU General Public License for more details.
  16  *
  17  *   You should have received a copy of the GNU General Public License
  18  *   along with this program; if not, write to the Free Software
  19  *   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  20  */
  21
  22 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  23
  24 #include <linux/kernel.h>
  25 #include <linux/module.h>
  26 #include <linux/init.h>
  27 #include <linux/time.h>
  28 #include <linux/timer.h>
  29 #include <linux/pps_kernel.h>
  30
  31 /*
  32  * Global variables
  33  */
  34
  35 static struct pps_device *pps;
  36 static struct timer_list ktimer;
  37
  38 /*
  39  * The kernel timer
  40  */
  41
  42 static void pps_ktimer_event(unsigned long ptr)
  43 {
  44         struct pps_event_time ts;
  45
  46         /* First of all we get the time stamp... */
  47         pps_get_ts(&ts);
  48
  49         dev_info(pps->dev, "PPS event at %lu\n", jiffies);
  50
  51         pps_event(pps, &ts, PPS_CAPTUREASSERT, NULL);
  52
  53         mod_timer(&ktimer, jiffies + HZ);
  54 }
  55
  56 /*
  57  * The echo function
  58  */
  59
  60 static void pps_ktimer_echo(struct pps_device *pps, int event, void *data)
  61 {
  62         dev_info(pps->dev, "echo %s %s\n",
  63                 event & PPS_CAPTUREASSERT ? "assert" : "",
  64                 event & PPS_CAPTURECLEAR ? "clear" : "");
  65 }
  66
  67 /*
  68  * The PPS info struct
  69  */
  70
  71 static struct pps_source_info pps_ktimer_info = {
  72         .name           = "ktimer",
  73         .path           = "",
  74         .mode           = PPS_CAPTUREASSERT | PPS_OFFSETASSERT |
  75                           PPS_ECHOASSERT |
  76                           PPS_CANWAIT | PPS_TSFMT_TSPEC,
  77         .echo           = pps_ktimer_echo,
  78         .owner          = THIS_MODULE,
  79 };
  80
  81 /*
  82  * Module staff
  83  */
  84
  85 static void __exit pps_ktimer_exit(void)
  86 {
  87         dev_info(pps->dev, "ktimer PPS source unregistered\n");
  88
  89         del_timer_sync(&ktimer);
  90         pps_unregister_source(pps);
  91 }
  92
  93 static int __init pps_ktimer_init(void)
  94 {
  95         pps = pps_register_source(&pps_ktimer_info,
  96                                 PPS_CAPTUREASSERT | PPS_OFFSETASSERT);
  97         if (pps == NULL) {
  98                 pr_err("cannot register PPS source\n");
  99                 return -ENOMEM;
 100         }
 101
 102         setup_timer(&ktimer, pps_ktimer_event, 0);
 103         mod_timer(&ktimer, jiffies + HZ);
 104
 105         dev_info(pps->dev, "ktimer PPS source registered\n");
 106
 107         return 0;
 108 }
 109
 110 module_init(pps_ktimer_init);
 111 module_exit(pps_ktimer_exit);
 112
 113 MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
 114 MODULE_DESCRIPTION("dummy PPS source by using a kernel timer (just for debug)");
 115 MODULE_LICENSE("GPL");