drivers/rtc/bfin_rtc.c

   1 /*
   2  * Copyright (c) 2004-2008 Analog Devices Inc.
   3  *
   4  * (C) Copyright 2001
   5  * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
   6  *
   7  * Licensed under the GPL-2 or later.
   8  */
   9
  10 #include <common.h>
  11 #include <command.h>
  12 #include <rtc.h>
  13
  14 #if defined(CONFIG_RTC_BFIN) && defined(CONFIG_CMD_DATE)
  15
  16 #include <asm/blackfin.h>
  17 #include <asm/mach-common/bits/rtc.h>
  18
  19 #define pr_stamp() debug("%s:%s:%i: here i am\n", __FILE__, __func__, __LINE__)
  20
  21 #define MIN_TO_SECS(x)    (60 * (x))
  22 #define HRS_TO_SECS(x)    (60 * MIN_TO_SECS(x))
  23 #define DAYS_TO_SECS(x)   (24 * HRS_TO_SECS(x))
  24
  25 #define NUM_SECS_IN_MIN   MIN_TO_SECS(1)
  26 #define NUM_SECS_IN_HR    HRS_TO_SECS(1)
  27 #define NUM_SECS_IN_DAY   DAYS_TO_SECS(1)
  28
  29 /* Our on-chip RTC has no notion of "reset" */
  30 void rtc_reset(void)
  31 {
  32         return;
  33 }
  34
  35 /* Wait for pending writes to complete */
  36 static void wait_for_complete(void)
  37 {
  38         pr_stamp();
  39         while (!(bfin_read_RTC_ISTAT() & WRITE_COMPLETE))
  40                 if (!(bfin_read_RTC_ISTAT() & WRITE_PENDING))
  41                         break;
  42         bfin_write_RTC_ISTAT(WRITE_COMPLETE);
  43 }
  44
  45 /* Enable the RTC prescaler enable register */
  46 int rtc_init(void)
  47 {
  48         pr_stamp();
  49         bfin_write_RTC_PREN(0x1);
  50         return 0;
  51 }
  52
  53 /* Set the time. Get the time_in_secs which is the number of seconds since Jan 1970 and set the RTC registers
  54  * based on this value.
  55  */
  56 void rtc_set(struct rtc_time *tmp)
  57 {
  58         unsigned long remain, days, hrs, mins, secs;
  59
  60         pr_stamp();
  61
  62         if (tmp == NULL) {
  63                 puts("Error setting the date/time\n");
  64                 return;
  65         }
  66
  67         wait_for_complete();
  68
  69         /* Calculate number of seconds this incoming time represents */
  70         remain = mktime(tmp->tm_year, tmp->tm_mon, tmp->tm_mday,
  71                         tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
  72
  73         /* Figure out how many days since epoch */
  74         days = remain / NUM_SECS_IN_DAY;
  75
  76         /* From the remaining secs, compute the hrs(0-23), mins(0-59) and secs(0-59) */
  77         remain = remain % NUM_SECS_IN_DAY;
  78         hrs = remain / NUM_SECS_IN_HR;
  79         remain = remain % NUM_SECS_IN_HR;
  80         mins = remain / NUM_SECS_IN_MIN;
  81         secs = remain % NUM_SECS_IN_MIN;
  82
  83         /* Encode these time values into our RTC_STAT register */
  84         bfin_write_RTC_STAT(SET_ALARM(days, hrs, mins, secs));
  85 }
  86
  87 /* Read the time from the RTC_STAT. time_in_seconds is seconds since Jan 1970 */
  88 int rtc_get(struct rtc_time *tmp)
  89 {
  90         uint32_t cur_rtc_stat;
  91         int time_in_sec;
  92         int tm_sec, tm_min, tm_hr, tm_day;
  93
  94         pr_stamp();
  95
  96         if (tmp == NULL) {
  97                 puts("Error getting the date/time\n");
  98                 return -1;
  99         }
 100
 101         wait_for_complete();
 102
 103         /* Read the RTC_STAT register */
 104         cur_rtc_stat = bfin_read_RTC_STAT();
 105
 106         /* Convert our encoded format into actual time values */
 107         tm_sec = (cur_rtc_stat & RTC_SEC) >> RTC_SEC_P;
 108         tm_min = (cur_rtc_stat & RTC_MIN) >> RTC_MIN_P;
 109         tm_hr  = (cur_rtc_stat & RTC_HR ) >> RTC_HR_P;
 110         tm_day = (cur_rtc_stat & RTC_DAY) >> RTC_DAY_P;
 111
 112         /* Calculate the total number of seconds since epoch */
 113         time_in_sec = (tm_sec) + MIN_TO_SECS(tm_min) + HRS_TO_SECS(tm_hr) + DAYS_TO_SECS(tm_day);
 114         to_tm(time_in_sec, tmp);
 115
 116         return 0;
 117 }
 118
 119 #endif