linux/include/asm-generic/rtc.h
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   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 */
  34static 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
  45static 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                time->tm_sec = bcd2bin(time->tm_sec);
  88                time->tm_min = bcd2bin(time->tm_min);
  89                time->tm_hour = bcd2bin(time->tm_hour);
  90                time->tm_mday = bcd2bin(time->tm_mday);
  91                time->tm_mon = bcd2bin(time->tm_mon);
  92                time->tm_year = bcd2bin(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#ifndef get_rtc_time
 112#define get_rtc_time    __get_rtc_time
 113#endif
 114
 115/* Set the current date and time in the real time clock. */
 116static 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                sec = bin2bcd(sec);
 167                min = bin2bcd(min);
 168                hrs = bin2bcd(hrs);
 169                day = bin2bcd(day);
 170                mon = bin2bcd(mon);
 171                yrs = bin2bcd(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#ifndef set_rtc_time
 198#define set_rtc_time    __set_rtc_time
 199#endif
 200
 201static inline unsigned int get_rtc_ss(void)
 202{
 203        struct rtc_time h;
 204
 205        get_rtc_time(&h);
 206        return h.tm_sec;
 207}
 208
 209static inline int get_rtc_pll(struct rtc_pll_info *pll)
 210{
 211        return -EINVAL;
 212}
 213static inline int set_rtc_pll(struct rtc_pll_info *pll)
 214{
 215        return -EINVAL;
 216}
 217
 218#endif /* __ASM_RTC_H__ */
 219
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