LXR linux/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
  35static struct pps_device *pps;
  36static struct timer_list ktimer;
  37
  38/*
  39 * The kernel timer
  40 */
  41
  42static 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        pps_event(pps, &ts, PPS_CAPTUREASSERT, NULL);
  50
  51        mod_timer(&ktimer, jiffies + HZ);
  52}
  53
  54/*
  55 * The PPS info struct
  56 */
  57
  58static struct pps_source_info pps_ktimer_info = {
  59        .name           = "ktimer",
  60        .path           = "",
  61        .mode           = PPS_CAPTUREASSERT | PPS_OFFSETASSERT |
  62                          PPS_ECHOASSERT |
  63                          PPS_CANWAIT | PPS_TSFMT_TSPEC,
  64        .owner          = THIS_MODULE,
  65};
  66
  67/*
  68 * Module staff
  69 */
  70
  71static void __exit pps_ktimer_exit(void)
  72{
  73        dev_info(pps->dev, "ktimer PPS source unregistered\n");
  74
  75        del_timer_sync(&ktimer);
  76        pps_unregister_source(pps);
  77}
  78
  79static int __init pps_ktimer_init(void)
  80{
  81        pps = pps_register_source(&pps_ktimer_info,
  82                                PPS_CAPTUREASSERT | PPS_OFFSETASSERT);
  83        if (pps == NULL) {
  84                pr_err("cannot register PPS source\n");
  85                return -ENOMEM;
  86        }
  87
  88        setup_timer(&ktimer, pps_ktimer_event, 0);
  89        mod_timer(&ktimer, jiffies + HZ);
  90
  91        dev_info(pps->dev, "ktimer PPS source registered\n");
  92
  93        return 0;
  94}
  95
  96module_init(pps_ktimer_init);
  97module_exit(pps_ktimer_exit);
  98
  99MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
 100MODULE_DESCRIPTION("dummy PPS source by using a kernel timer (just for debug)");
 101MODULE_LICENSE("GPL");
 102