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 #include <linux/delay.h>
  19
  20 #define RTC_PIE 0x40            /* periodic interrupt enable */
  21 #define RTC_AIE 0x20            /* alarm interrupt enable */
  22 #define RTC_UIE 0x10            /* update-finished interrupt enable */
  23
  24 /* some dummy definitions */
  25 #define RTC_BATT_BAD 0x100      /* battery bad */
  26 #define RTC_SQWE 0x08           /* enable square-wave output */
  27 #define RTC_DM_BINARY 0x04      /* all time/date values are BCD if clear */
  28 #define RTC_24H 0x02            /* 24 hour mode - else hours bit 7 means pm */
  29 #define RTC_DST_EN 0x01         /* auto switch DST - works f. USA only */
  30
  31 /*
  32  * Returns true if a clock update is in progress
  33  */
  34 static inline unsigned char rtc_is_updating(void)
  35 {
  36         unsigned char uip;
  37         unsigned long flags;
  38
  39         spin_lock_irqsave(&rtc_lock, flags);
  40         uip = (CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP);
  41         spin_unlock_irqrestore(&rtc_lock, flags);
  42         return uip;
  43 }
  44
  45 static inline unsigned int get_rtc_time(struct rtc_time *time)
  46 {
  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 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         if (rtc_is_updating())
  64                 mdelay(20);
  65
  66         /*
  67          * Only the values that we read from the RTC are set. We leave
  68          * tm_wday, tm_yday and tm_isdst untouched. Even though the
  69          * RTC has RTC_DAY_OF_WEEK, we ignore it, as it is only updated
  70          * by the RTC when initially set to a non-zero value.
  71          */
  72         spin_lock_irqsave(&rtc_lock, flags);
  73         time->tm_sec = CMOS_READ(RTC_SECONDS);
  74         time->tm_min = CMOS_READ(RTC_MINUTES);
  75         time->tm_hour = CMOS_READ(RTC_HOURS);
  76         time->tm_mday = CMOS_READ(RTC_DAY_OF_MONTH);
  77         time->tm_mon = CMOS_READ(RTC_MONTH);
  78         time->tm_year = CMOS_READ(RTC_YEAR);
  79 #ifdef CONFIG_MACH_DECSTATION
  80         real_year = CMOS_READ(RTC_DEC_YEAR);
  81 #endif
  82         ctrl = CMOS_READ(RTC_CONTROL);
  83         spin_unlock_irqrestore(&rtc_lock, flags);
  84
  85         if (!(ctrl & RTC_DM_BINARY) || RTC_ALWAYS_BCD)
  86         {
  87                 BCD_TO_BIN(time->tm_sec);
  88                 BCD_TO_BIN(time->tm_min);
  89                 BCD_TO_BIN(time->tm_hour);
  90                 BCD_TO_BIN(time->tm_mday);
  91                 BCD_TO_BIN(time->tm_mon);
  92                 BCD_TO_BIN(time->tm_year);
  93         }
  94
  95 #ifdef CONFIG_MACH_DECSTATION
  96         time->tm_year += real_year - 72;
  97 #endif
  98
  99         /*
 100          * Account for differences between how the RTC uses the values
 101          * and how they are defined in a struct rtc_time;
 102          */
 103         if (time->tm_year <= 69)
 104                 time->tm_year += 100;
 105
 106         time->tm_mon--;
 107
 108         return RTC_24H;
 109 }
 110
 111 /* Set the current date and time in the real time clock. */
 112 static inline int set_rtc_time(struct rtc_time *time)
 113 {
 114         unsigned long flags;
 115         unsigned char mon, day, hrs, min, sec;
 116         unsigned char save_control, save_freq_select;
 117         unsigned int yrs;
 118 #ifdef CONFIG_MACH_DECSTATION
 119         unsigned int real_yrs, leap_yr;
 120 #endif
 121
 122         yrs = time->tm_year;
 123         mon = time->tm_mon + 1;   /* tm_mon starts at zero */
 124         day = time->tm_mday;
 125         hrs = time->tm_hour;
 126         min = time->tm_min;
 127         sec = time->tm_sec;
 128
 129         if (yrs > 255)  /* They are unsigned */
 130                 return -EINVAL;
 131
 132         spin_lock_irqsave(&rtc_lock, flags);
 133 #ifdef CONFIG_MACH_DECSTATION
 134         real_yrs = yrs;
 135         leap_yr = ((!((yrs + 1900) % 4) && ((yrs + 1900) % 100)) ||
 136                         !((yrs + 1900) % 400));
 137         yrs = 72;
 138
 139         /*
 140          * We want to keep the year set to 73 until March
 141          * for non-leap years, so that Feb, 29th is handled
 142          * correctly.
 143          */
 144         if (!leap_yr && mon < 3) {
 145                 real_yrs--;
 146                 yrs = 73;
 147         }
 148 #endif
 149         /* These limits and adjustments are independent of
 150          * whether the chip is in binary mode or not.
 151          */
 152         if (yrs > 169) {
 153                 spin_unlock_irqrestore(&rtc_lock, flags);
 154                 return -EINVAL;
 155         }
 156
 157         if (yrs >= 100)
 158                 yrs -= 100;
 159
 160         if (!(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY)
 161             || RTC_ALWAYS_BCD) {
 162                 BIN_TO_BCD(sec);
 163                 BIN_TO_BCD(min);
 164                 BIN_TO_BCD(hrs);
 165                 BIN_TO_BCD(day);
 166                 BIN_TO_BCD(mon);
 167                 BIN_TO_BCD(yrs);
 168         }
 169
 170         save_control = CMOS_READ(RTC_CONTROL);
 171         CMOS_WRITE((save_control|RTC_SET), RTC_CONTROL);
 172         save_freq_select = CMOS_READ(RTC_FREQ_SELECT);
 173         CMOS_WRITE((save_freq_select|RTC_DIV_RESET2), RTC_FREQ_SELECT);
 174
 175 #ifdef CONFIG_MACH_DECSTATION
 176         CMOS_WRITE(real_yrs, RTC_DEC_YEAR);
 177 #endif
 178         CMOS_WRITE(yrs, RTC_YEAR);
 179         CMOS_WRITE(mon, RTC_MONTH);
 180         CMOS_WRITE(day, RTC_DAY_OF_MONTH);
 181         CMOS_WRITE(hrs, RTC_HOURS);
 182         CMOS_WRITE(min, RTC_MINUTES);
 183         CMOS_WRITE(sec, RTC_SECONDS);
 184
 185         CMOS_WRITE(save_control, RTC_CONTROL);
 186         CMOS_WRITE(save_freq_select, RTC_FREQ_SELECT);
 187
 188         spin_unlock_irqrestore(&rtc_lock, flags);
 189
 190         return 0;
 191 }
 192
 193 static inline unsigned int get_rtc_ss(void)
 194 {
 195         struct rtc_time h;
 196
 197         get_rtc_time(&h);
 198         return h.tm_sec;
 199 }
 200
 201 static inline int get_rtc_pll(struct rtc_pll_info *pll)
 202 {
 203         return -EINVAL;
 204 }
 205 static inline int set_rtc_pll(struct rtc_pll_info *pll)
 206 {
 207         return -EINVAL;
 208 }
 209
 210 #endif /* __ASM_RTC_H__ */