include/asm-generic/rtc.h

   1 /*
   2  * include/asm-generic/rtc.h
   3  *
   4  * Author: Tom Rini <trini@mvista.com>
   5  *
   6  * Based on:
   7  * drivers/char/rtc.c
   8  *
   9  * Please read the COPYING file for all license details.
  10  */
  11
  12 #ifndef __ASM_RTC_H__
  13 #define __ASM_RTC_H__
  14
  15 #include <linux/mc146818rtc.h>
  16 #include <linux/rtc.h>
  17 #include <linux/bcd.h>
  18
  19 #define RTC_PIE 0x40            /* periodic interrupt enable */
  20 #define RTC_AIE 0x20            /* alarm interrupt enable */
  21 #define RTC_UIE 0x10            /* update-finished interrupt enable */
  22
  23 /* some dummy definitions */
  24 #define RTC_BATT_BAD 0x100      /* battery bad */
  25 #define RTC_SQWE 0x08           /* enable square-wave output */
  26 #define RTC_DM_BINARY 0x04      /* all time/date values are BCD if clear */
  27 #define RTC_24H 0x02            /* 24 hour mode - else hours bit 7 means pm */
  28 #define RTC_DST_EN 0x01         /* auto switch DST - works f. USA only */
  29
  30 /*
  31  * Returns true if a clock update is in progress
  32  */
  33 static inline unsigned char rtc_is_updating(void)
  34 {
  35         unsigned char uip;
  36         unsigned long flags;
  37
  38         spin_lock_irqsave(&rtc_lock, flags);
  39         uip = (CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP);
  40         spin_unlock_irqrestore(&rtc_lock, flags);
  41         return uip;
  42 }
  43
  44 static inline unsigned int get_rtc_time(struct rtc_time *time)
  45 {
  46         unsigned long uip_watchdog = jiffies;
  47         unsigned char ctrl;
  48         unsigned long flags;
  49
  50 #ifdef CONFIG_MACH_DECSTATION
  51         unsigned int real_year;
  52 #endif
  53
  54         /*
  55          * read RTC once any update in progress is done. The update
  56          * can take just over 2ms. We wait 10 to 20ms. There is no need to
  57          * to poll-wait (up to 1s - eeccch) for the falling edge of RTC_UIP.
  58          * If you need to know *exactly* when a second has started, enable
  59          * periodic update complete interrupts, (via ioctl) and then
  60          * immediately read /dev/rtc which will block until you get the IRQ.
  61          * Once the read clears, read the RTC time (again via ioctl). Easy.
  62          */
  63
  64         if (rtc_is_updating() != 0)
  65                 while (jiffies - uip_watchdog < 2*HZ/100) {
  66                         barrier();
  67                         cpu_relax();
  68                 }
  69
  70         /*
  71          * Only the values that we read from the RTC are set. We leave
  72          * tm_wday, tm_yday and tm_isdst untouched. Even though the
  73          * RTC has RTC_DAY_OF_WEEK, we ignore it, as it is only updated
  74          * by the RTC when initially set to a non-zero value.
  75          */
  76         spin_lock_irqsave(&rtc_lock, flags);
  77         time->tm_sec = CMOS_READ(RTC_SECONDS);
  78         time->tm_min = CMOS_READ(RTC_MINUTES);
  79         time->tm_hour = CMOS_READ(RTC_HOURS);
  80         time->tm_mday = CMOS_READ(RTC_DAY_OF_MONTH);
  81         time->tm_mon = CMOS_READ(RTC_MONTH);
  82         time->tm_year = CMOS_READ(RTC_YEAR);
  83 #ifdef CONFIG_MACH_DECSTATION
  84         real_year = CMOS_READ(RTC_DEC_YEAR);
  85 #endif
  86         ctrl = CMOS_READ(RTC_CONTROL);
  87         spin_unlock_irqrestore(&rtc_lock, flags);
  88
  89         if (!(ctrl & RTC_DM_BINARY) || RTC_ALWAYS_BCD)
  90         {
  91                 BCD_TO_BIN(time->tm_sec);
  92                 BCD_TO_BIN(time->tm_min);
  93                 BCD_TO_BIN(time->tm_hour);
  94                 BCD_TO_BIN(time->tm_mday);
  95                 BCD_TO_BIN(time->tm_mon);
  96                 BCD_TO_BIN(time->tm_year);
  97         }
  98
  99 #ifdef CONFIG_MACH_DECSTATION
 100         time->tm_year += real_year - 72;
 101 #endif
 102
 103         /*
 104          * Account for differences between how the RTC uses the values
 105          * and how they are defined in a struct rtc_time;
 106          */
 107         if (time->tm_year <= 69)
 108                 time->tm_year += 100;
 109
 110         time->tm_mon--;
 111
 112         return RTC_24H;
 113 }
 114
 115 /* Set the current date and time in the real time clock. */
 116 static inline int set_rtc_time(struct rtc_time *time)
 117 {
 118         unsigned long flags;
 119         unsigned char mon, day, hrs, min, sec;
 120         unsigned char save_control, save_freq_select;
 121         unsigned int yrs;
 122 #ifdef CONFIG_MACH_DECSTATION
 123         unsigned int real_yrs, leap_yr;
 124 #endif
 125
 126         yrs = time->tm_year;
 127         mon = time->tm_mon + 1;   /* tm_mon starts at zero */
 128         day = time->tm_mday;
 129         hrs = time->tm_hour;
 130         min = time->tm_min;
 131         sec = time->tm_sec;
 132
 133         if (yrs > 255)  /* They are unsigned */
 134                 return -EINVAL;
 135
 136         spin_lock_irqsave(&rtc_lock, flags);
 137 #ifdef CONFIG_MACH_DECSTATION
 138         real_yrs = yrs;
 139         leap_yr = ((!((yrs + 1900) % 4) && ((yrs + 1900) % 100)) ||
 140                         !((yrs + 1900) % 400));
 141         yrs = 72;
 142
 143         /*
 144          * We want to keep the year set to 73 until March
 145          * for non-leap years, so that Feb, 29th is handled
 146          * correctly.
 147          */
 148         if (!leap_yr && mon < 3) {
 149                 real_yrs--;
 150                 yrs = 73;
 151         }
 152 #endif
 153         /* These limits and adjustments are independent of
 154          * whether the chip is in binary mode or not.
 155          */
 156         if (yrs > 169) {
 157                 spin_unlock_irqrestore(&rtc_lock, flags);
 158                 return -EINVAL;
 159         }
 160
 161         if (yrs >= 100)
 162                 yrs -= 100;
 163
 164         if (!(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY)
 165             || RTC_ALWAYS_BCD) {
 166                 BIN_TO_BCD(sec);
 167                 BIN_TO_BCD(min);
 168                 BIN_TO_BCD(hrs);
 169                 BIN_TO_BCD(day);
 170                 BIN_TO_BCD(mon);
 171                 BIN_TO_BCD(yrs);
 172         }
 173
 174         save_control = CMOS_READ(RTC_CONTROL);
 175         CMOS_WRITE((save_control|RTC_SET), RTC_CONTROL);
 176         save_freq_select = CMOS_READ(RTC_FREQ_SELECT);
 177         CMOS_WRITE((save_freq_select|RTC_DIV_RESET2), RTC_FREQ_SELECT);
 178
 179 #ifdef CONFIG_MACH_DECSTATION
 180         CMOS_WRITE(real_yrs, RTC_DEC_YEAR);
 181 #endif
 182         CMOS_WRITE(yrs, RTC_YEAR);
 183         CMOS_WRITE(mon, RTC_MONTH);
 184         CMOS_WRITE(day, RTC_DAY_OF_MONTH);
 185         CMOS_WRITE(hrs, RTC_HOURS);
 186         CMOS_WRITE(min, RTC_MINUTES);
 187         CMOS_WRITE(sec, RTC_SECONDS);
 188
 189         CMOS_WRITE(save_control, RTC_CONTROL);
 190         CMOS_WRITE(save_freq_select, RTC_FREQ_SELECT);
 191
 192         spin_unlock_irqrestore(&rtc_lock, flags);
 193
 194         return 0;
 195 }
 196
 197 static inline unsigned int get_rtc_ss(void)
 198 {
 199         struct rtc_time h;
 200
 201         get_rtc_time(&h);
 202         return h.tm_sec;
 203 }
 204
 205 static inline int get_rtc_pll(struct rtc_pll_info *pll)
 206 {
 207         return -EINVAL;
 208 }
 209 static inline int set_rtc_pll(struct rtc_pll_info *pll)
 210 {
 211         return -EINVAL;
 212 }
 213
 214 #endif /* __ASM_RTC_H__ */