rtc.h

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/* 
 * include/asm-generic/rtc.h
 *
 * Author: Tom Rini <[email protected]>
 *
 * Based on:
 * drivers/char/rtc.c
 *
 * Please read the COPYING file for all license details.
 */

#ifndef __ASM_RTC_H__
#define __ASM_RTC_H__

#include <linux/mc146818rtc.h>
#include <linux/rtc.h>
#include <linux/bcd.h>
#include <linux/delay.h>

#define RTC_PIE 0x40        /* periodic interrupt enable */
#define RTC_AIE 0x20        /* alarm interrupt enable */
#define RTC_UIE 0x10        /* update-finished interrupt enable */

/* some dummy definitions */
#define RTC_BATT_BAD 0x100  /* battery bad */
#define RTC_SQWE 0x08       /* enable square-wave output */
#define RTC_DM_BINARY 0x04  /* all time/date values are BCD if clear */
#define RTC_24H 0x02        /* 24 hour mode - else hours bit 7 means pm */
#define RTC_DST_EN 0x01         /* auto switch DST - works f. USA only */

/*
 * Returns true if a clock update is in progress
 */
static inline unsigned char rtc_is_updating(void)
{
    unsigned char uip;
    unsigned long flags;

    spin_lock_irqsave(&rtc_lock, flags);
    uip = (CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP);
    spin_unlock_irqrestore(&rtc_lock, flags);
    return uip;
}

static inline unsigned int __get_rtc_time(struct rtc_time *time)
{
    unsigned char ctrl;
    unsigned long flags;

#ifdef CONFIG_MACH_DECSTATION
    unsigned int real_year;
#endif

    /*
     * read RTC once any update in progress is done. The update
     * can take just over 2ms. We wait 20ms. There is no need to
     * to poll-wait (up to 1s - eeccch) for the falling edge of RTC_UIP.
     * If you need to know *exactly* when a second has started, enable
     * periodic update complete interrupts, (via ioctl) and then 
     * immediately read /dev/rtc which will block until you get the IRQ.
     * Once the read clears, read the RTC time (again via ioctl). Easy.
     */
    if (rtc_is_updating())
        mdelay(20);

    /*
     * Only the values that we read from the RTC are set. We leave
     * tm_wday, tm_yday and tm_isdst untouched. Even though the
     * RTC has RTC_DAY_OF_WEEK, we ignore it, as it is only updated
     * by the RTC when initially set to a non-zero value.
     */
    spin_lock_irqsave(&rtc_lock, flags);
    time->tm_sec = CMOS_READ(RTC_SECONDS);
    time->tm_min = CMOS_READ(RTC_MINUTES);
    time->tm_hour = CMOS_READ(RTC_HOURS);
    time->tm_mday = CMOS_READ(RTC_DAY_OF_MONTH);
    time->tm_mon = CMOS_READ(RTC_MONTH);
    time->tm_year = CMOS_READ(RTC_YEAR);
#ifdef CONFIG_MACH_DECSTATION
    real_year = CMOS_READ(RTC_DEC_YEAR);
#endif
    ctrl = CMOS_READ(RTC_CONTROL);
    spin_unlock_irqrestore(&rtc_lock, flags);

    if (!(ctrl & RTC_DM_BINARY) || RTC_ALWAYS_BCD)
    {
        time->tm_sec = bcd2bin(time->tm_sec);
        time->tm_min = bcd2bin(time->tm_min);
        time->tm_hour = bcd2bin(time->tm_hour);
        time->tm_mday = bcd2bin(time->tm_mday);
        time->tm_mon = bcd2bin(time->tm_mon);
        time->tm_year = bcd2bin(time->tm_year);
    }

#ifdef CONFIG_MACH_DECSTATION
    time->tm_year += real_year - 72;
#endif

    /*
     * Account for differences between how the RTC uses the values
     * and how they are defined in a struct rtc_time;
     */
    if (time->tm_year <= 69)
        time->tm_year += 100;

    time->tm_mon--;

    return RTC_24H;
}

#ifndef get_rtc_time
#define get_rtc_time    __get_rtc_time
#endif

/* Set the current date and time in the real time clock. */
static inline int __set_rtc_time(struct rtc_time *time)
{
    unsigned long flags;
    unsigned char mon, day, hrs, min, sec;
    unsigned char save_control, save_freq_select;
    unsigned int yrs;
#ifdef CONFIG_MACH_DECSTATION
    unsigned int real_yrs, leap_yr;
#endif

    yrs = time->tm_year;
    mon = time->tm_mon + 1;   /* tm_mon starts at zero */
    day = time->tm_mday;
    hrs = time->tm_hour;
    min = time->tm_min;
    sec = time->tm_sec;

    if (yrs > 255)  /* They are unsigned */
        return -EINVAL;

    spin_lock_irqsave(&rtc_lock, flags);
#ifdef CONFIG_MACH_DECSTATION
    real_yrs = yrs;
    leap_yr = ((!((yrs + 1900) % 4) && ((yrs + 1900) % 100)) ||
            !((yrs + 1900) % 400));
    yrs = 72;

    /*
     * We want to keep the year set to 73 until March
     * for non-leap years, so that Feb, 29th is handled
     * correctly.
     */
    if (!leap_yr && mon < 3) {
        real_yrs--;
        yrs = 73;
    }
#endif
    /* These limits and adjustments are independent of
     * whether the chip is in binary mode or not.
     */
    if (yrs > 169) {
        spin_unlock_irqrestore(&rtc_lock, flags);
        return -EINVAL;
    }

    if (yrs >= 100)
        yrs -= 100;

    if (!(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY)
        || RTC_ALWAYS_BCD) {
        sec = bin2bcd(sec);
        min = bin2bcd(min);
        hrs = bin2bcd(hrs);
        day = bin2bcd(day);
        mon = bin2bcd(mon);
        yrs = bin2bcd(yrs);
    }

    save_control = CMOS_READ(RTC_CONTROL);
    CMOS_WRITE((save_control|RTC_SET), RTC_CONTROL);
    save_freq_select = CMOS_READ(RTC_FREQ_SELECT);
    CMOS_WRITE((save_freq_select|RTC_DIV_RESET2), RTC_FREQ_SELECT);

#ifdef CONFIG_MACH_DECSTATION
    CMOS_WRITE(real_yrs, RTC_DEC_YEAR);
#endif
    CMOS_WRITE(yrs, RTC_YEAR);
    CMOS_WRITE(mon, RTC_MONTH);
    CMOS_WRITE(day, RTC_DAY_OF_MONTH);
    CMOS_WRITE(hrs, RTC_HOURS);
    CMOS_WRITE(min, RTC_MINUTES);
    CMOS_WRITE(sec, RTC_SECONDS);

    CMOS_WRITE(save_control, RTC_CONTROL);
    CMOS_WRITE(save_freq_select, RTC_FREQ_SELECT);

    spin_unlock_irqrestore(&rtc_lock, flags);

    return 0;
}

#ifndef set_rtc_time
#define set_rtc_time    __set_rtc_time
#endif

static inline unsigned int get_rtc_ss(void)
{
    struct rtc_time h;

    get_rtc_time(&h);
    return h.tm_sec;
}

static inline int get_rtc_pll(struct rtc_pll_info *pll)
{
    return -EINVAL;
}
static inline int set_rtc_pll(struct rtc_pll_info *pll)
{
    return -EINVAL;
}

#endif /* __ASM_RTC_H__ */