Subversion Repositories test_project

/*

 * RTC subsystem, initialize system time on startup

 *

 * Copyright (C) 2005 Tower Technologies

 * Author: Alessandro Zummo <a.zummo@towertech.it>

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 as

 * published by the Free Software Foundation.

*/

#include <linux/rtc.h>

/* IMPORTANT: the RTC only stores whole seconds. It is arbitrary

 * whether it stores the most close value or the value with partial

 * seconds truncated. However, it is important that we use it to store

 * the truncated value. This is because otherwise it is necessary,

 * in an rtc sync function, to read both xtime.tv_sec and

 * xtime.tv_nsec. On some processors (i.e. ARM), an atomic read

 * of >32bits is not possible. So storing the most close value would

 * slow down the sync API. So here we have the truncated value and

 * the best guess is to add 0.5s.

 */

static int __init rtc_hctosys(void)

{

        int err;

        struct rtc_time tm;

        struct rtc_device *rtc = rtc_class_open(CONFIG_RTC_HCTOSYS_DEVICE);

        if (rtc == NULL) {

                printk("%s: unable to open rtc device (%s)\n",

                        __FILE__, CONFIG_RTC_HCTOSYS_DEVICE);

                return -ENODEV;

        }

        err = rtc_read_time(rtc, &tm);

        if (err == 0) {

                err = rtc_valid_tm(&tm);

                if (err == 0) {

                        struct timespec tv;

                        tv.tv_nsec = NSEC_PER_SEC >> 1;

                        rtc_tm_to_time(&tm, &tv.tv_sec);

                        do_settimeofday(&tv);

                        dev_info(rtc->dev.parent,

                                "setting system clock to "

                                "%d-%02d-%02d %02d:%02d:%02d UTC (%u)\n",

                                tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,

                                tm.tm_hour, tm.tm_min, tm.tm_sec,

                                (unsigned int) tv.tv_sec);

                }

                else

                        dev_err(rtc->dev.parent,

                                "hctosys: invalid date/time\n");

        }

        else

                dev_err(rtc->dev.parent,

                        "hctosys: unable to read the hardware clock\n");

        rtc_class_close(rtc);

        return 0;

}

late_initcall(rtc_hctosys);