arch/powerpc/sysdev/timer.c

   1 /*
   2  * Common code to keep time when machine suspends.
   3  *
   4  * Copyright 2007       Johannes Berg <johannes@sipsolutions.net>
   5  *
   6  * GPLv2
   7  */
   8
   9 #include <linux/time.h>
  10 #include <linux/sysdev.h>
  11 #include <asm/rtc.h>
  12
  13 static unsigned long suspend_rtc_time;
  14
  15 /*
  16  * Reset the time after a sleep.
  17  */
  18 static int timer_resume(struct sys_device *dev)
  19 {
  20         struct timeval tv;
  21         struct timespec ts;
  22         struct rtc_time cur_rtc_tm;
  23         unsigned long cur_rtc_time, diff;
  24
  25         /* get current RTC time and convert to seconds */
  26         get_rtc_time(&cur_rtc_tm);
  27         cur_rtc_time = mktime(cur_rtc_tm.tm_year + 1900,
  28                               cur_rtc_tm.tm_mon + 1,
  29                               cur_rtc_tm.tm_mday,
  30                               cur_rtc_tm.tm_hour,
  31                               cur_rtc_tm.tm_min,
  32                               cur_rtc_tm.tm_sec);
  33
  34         diff = cur_rtc_time - suspend_rtc_time;
  35
  36         /* adjust time of day by seconds that elapsed while
  37          * we were suspended */
  38         do_gettimeofday(&tv);
  39         ts.tv_sec = tv.tv_sec + diff;
  40         ts.tv_nsec = tv.tv_usec * NSEC_PER_USEC;
  41         do_settimeofday(&ts);
  42
  43         return 0;
  44 }
  45
  46 static int timer_suspend(struct sys_device *dev, pm_message_t state)
  47 {
  48         struct rtc_time suspend_rtc_tm;
  49         WARN_ON(!ppc_md.get_rtc_time);
  50
  51         get_rtc_time(&suspend_rtc_tm);
  52         suspend_rtc_time = mktime(suspend_rtc_tm.tm_year + 1900,
  53                                   suspend_rtc_tm.tm_mon + 1,
  54                                   suspend_rtc_tm.tm_mday,
  55                                   suspend_rtc_tm.tm_hour,
  56                                   suspend_rtc_tm.tm_min,
  57                                   suspend_rtc_tm.tm_sec);
  58
  59         return 0;
  60 }
  61
  62 static struct sysdev_class timer_sysclass = {
  63         .resume = timer_resume,
  64         .suspend = timer_suspend,
  65         set_kset_name("timer"),
  66 };
  67
  68 static struct sys_device device_timer = {
  69         .id = 0,
  70         .cls = &timer_sysclass,
  71 };
  72
  73 static int time_init_device(void)
  74 {
  75         int error = sysdev_class_register(&timer_sysclass);
  76         if (!error)
  77                 error = sysdev_register(&device_timer);
  78         return error;
  79 }
  80
  81 device_initcall(time_init_device);