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