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