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 #ifdef CONFIG_ACPI
  20 #include <linux/acpi.h>
  21 #endif
  22
  23 #define RTC_PIE 0x40            /* periodic interrupt enable */
  24 #define RTC_AIE 0x20            /* alarm interrupt enable */
  25 #define RTC_UIE 0x10            /* update-finished interrupt enable */
  26
  27 /* some dummy definitions */
  28 #define RTC_BATT_BAD 0x100      /* battery bad */
  29 #define RTC_SQWE 0x08           /* enable square-wave output */
  30 #define RTC_DM_BINARY 0x04      /* all time/date values are BCD if clear */
  31 #define RTC_24H 0x02            /* 24 hour mode - else hours bit 7 means pm */
  32 #define RTC_DST_EN 0x01         /* auto switch DST - works f. USA only */
  33
  34 /*
  35  * Returns true if a clock update is in progress
  36  */
  37 static inline unsigned char rtc_is_updating(void)
  38 {
  39         unsigned char uip;
  40         unsigned long flags;
  41
  42         spin_lock_irqsave(&rtc_lock, flags);
  43         uip = (CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP);
  44         spin_unlock_irqrestore(&rtc_lock, flags);
  45         return uip;
  46 }
  47
  48 static inline unsigned int __get_rtc_time(struct rtc_time *time)
  49 {
  50         unsigned char ctrl;
  51         unsigned long flags;
  52         unsigned char century = 0;
  53
  54 #ifdef CONFIG_MACH_DECSTATION
  55         unsigned int real_year;
  56 #endif
  57
  58         /*
  59          * read RTC once any update in progress is done. The update
  60          * can take just over 2ms. We wait 20ms. There is no need to
  61          * to poll-wait (up to 1s - eeccch) for the falling edge of RTC_UIP.
  62          * If you need to know *exactly* when a second has started, enable
  63          * periodic update complete interrupts, (via ioctl) and then
  64          * immediately read /dev/rtc which will block until you get the IRQ.
  65          * Once the read clears, read the RTC time (again via ioctl). Easy.
  66          */
  67         if (rtc_is_updating())
  68                 mdelay(20);
  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 #ifdef CONFIG_ACPI
  87         if (acpi_gbl_FADT.header.revision >= FADT2_REVISION_ID &&
  88             acpi_gbl_FADT.century)
  89                 century = CMOS_READ(acpi_gbl_FADT.century);
  90 #endif
  91         ctrl = CMOS_READ(RTC_CONTROL);
  92         spin_unlock_irqrestore(&rtc_lock, flags);
  93
  94         if (!(ctrl & RTC_DM_BINARY) || RTC_ALWAYS_BCD)
  95         {
  96                 time->tm_sec = bcd2bin(time->tm_sec);
  97                 time->tm_min = bcd2bin(time->tm_min);
  98                 time->tm_hour = bcd2bin(time->tm_hour);
  99                 time->tm_mday = bcd2bin(time->tm_mday);
 100                 time->tm_mon = bcd2bin(time->tm_mon);
 101                 time->tm_year = bcd2bin(time->tm_year);
 102                 century = bcd2bin(century);
 103         }
 104
 105 #ifdef CONFIG_MACH_DECSTATION
 106         time->tm_year += real_year - 72;
 107 #endif
 108
 109         if (century)
 110                 time->tm_year += (century - 19) * 100;
 111
 112         /*
 113          * Account for differences between how the RTC uses the values
 114          * and how they are defined in a struct rtc_time;
 115          */
 116         if (time->tm_year <= 69)
 117                 time->tm_year += 100;
 118
 119         time->tm_mon--;
 120
 121         return RTC_24H;
 122 }
 123
 124 #ifndef get_rtc_time
 125 #define get_rtc_time    __get_rtc_time
 126 #endif
 127
 128 /* Set the current date and time in the real time clock. */
 129 static inline int __set_rtc_time(struct rtc_time *time)
 130 {
 131         unsigned long flags;
 132         unsigned char mon, day, hrs, min, sec;
 133         unsigned char save_control, save_freq_select;
 134         unsigned int yrs;
 135 #ifdef CONFIG_MACH_DECSTATION
 136         unsigned int real_yrs, leap_yr;
 137 #endif
 138         unsigned char century = 0;
 139
 140         yrs = time->tm_year;
 141         mon = time->tm_mon + 1;   /* tm_mon starts at zero */
 142         day = time->tm_mday;
 143         hrs = time->tm_hour;
 144         min = time->tm_min;
 145         sec = time->tm_sec;
 146
 147         if (yrs > 255)  /* They are unsigned */
 148                 return -EINVAL;
 149
 150         spin_lock_irqsave(&rtc_lock, flags);
 151 #ifdef CONFIG_MACH_DECSTATION
 152         real_yrs = yrs;
 153         leap_yr = ((!((yrs + 1900) % 4) && ((yrs + 1900) % 100)) ||
 154                         !((yrs + 1900) % 400));
 155         yrs = 72;
 156
 157         /*
 158          * We want to keep the year set to 73 until March
 159          * for non-leap years, so that Feb, 29th is handled
 160          * correctly.
 161          */
 162         if (!leap_yr && mon < 3) {
 163                 real_yrs--;
 164                 yrs = 73;
 165         }
 166 #endif
 167
 168 #ifdef CONFIG_ACPI
 169         if (acpi_gbl_FADT.header.revision >= FADT2_REVISION_ID &&
 170             acpi_gbl_FADT.century) {
 171                 century = (yrs + 1900) / 100;
 172                 yrs %= 100;
 173         }
 174 #endif
 175
 176         /* These limits and adjustments are independent of
 177          * whether the chip is in binary mode or not.
 178          */
 179         if (yrs > 169) {
 180                 spin_unlock_irqrestore(&rtc_lock, flags);
 181                 return -EINVAL;
 182         }
 183
 184         if (yrs >= 100)
 185                 yrs -= 100;
 186
 187         if (!(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY)
 188             || RTC_ALWAYS_BCD) {
 189                 sec = bin2bcd(sec);
 190                 min = bin2bcd(min);
 191                 hrs = bin2bcd(hrs);
 192                 day = bin2bcd(day);
 193                 mon = bin2bcd(mon);
 194                 yrs = bin2bcd(yrs);
 195                 century = bin2bcd(century);
 196         }
 197
 198         save_control = CMOS_READ(RTC_CONTROL);
 199         CMOS_WRITE((save_control|RTC_SET), RTC_CONTROL);
 200         save_freq_select = CMOS_READ(RTC_FREQ_SELECT);
 201         CMOS_WRITE((save_freq_select|RTC_DIV_RESET2), RTC_FREQ_SELECT);
 202
 203 #ifdef CONFIG_MACH_DECSTATION
 204         CMOS_WRITE(real_yrs, RTC_DEC_YEAR);
 205 #endif
 206         CMOS_WRITE(yrs, RTC_YEAR);
 207         CMOS_WRITE(mon, RTC_MONTH);
 208         CMOS_WRITE(day, RTC_DAY_OF_MONTH);
 209         CMOS_WRITE(hrs, RTC_HOURS);
 210         CMOS_WRITE(min, RTC_MINUTES);
 211         CMOS_WRITE(sec, RTC_SECONDS);
 212 #ifdef CONFIG_ACPI
 213         if (acpi_gbl_FADT.header.revision >= FADT2_REVISION_ID &&
 214             acpi_gbl_FADT.century)
 215                 CMOS_WRITE(century, acpi_gbl_FADT.century);
 216 #endif
 217
 218         CMOS_WRITE(save_control, RTC_CONTROL);
 219         CMOS_WRITE(save_freq_select, RTC_FREQ_SELECT);
 220
 221         spin_unlock_irqrestore(&rtc_lock, flags);
 222
 223         return 0;
 224 }
 225
 226 #ifndef set_rtc_time
 227 #define set_rtc_time    __set_rtc_time
 228 #endif
 229
 230 static inline unsigned int get_rtc_ss(void)
 231 {
 232         struct rtc_time h;
 233
 234         get_rtc_time(&h);
 235         return h.tm_sec;
 236 }
 237
 238 static inline int get_rtc_pll(struct rtc_pll_info *pll)
 239 {
 240         return -EINVAL;
 241 }
 242 static inline int set_rtc_pll(struct rtc_pll_info *pll)
 243 {
 244         return -EINVAL;
 245 }
 246
 247 #endif /* __ASM_RTC_H__ */