Release 4.7 drivers/rtc/hctosys.c
/*
* 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.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#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 = -ENODEV;
struct rtc_time tm;
struct timespec64 tv64 = {
.tv_nsec = NSEC_PER_SEC >> 1,
};
struct rtc_device *rtc = rtc_class_open(CONFIG_RTC_HCTOSYS_DEVICE);
if (rtc == NULL) {
pr_info("unable to open rtc device (%s)\n",
CONFIG_RTC_HCTOSYS_DEVICE);
goto err_open;
}
err = rtc_read_time(rtc, &tm);
if (err) {
dev_err(rtc->dev.parent,
"hctosys: unable to read the hardware clock\n");
goto err_read;
}
tv64.tv_sec = rtc_tm_to_time64(&tm);
err = do_settimeofday64(&tv64);
dev_info(rtc->dev.parent,
"setting system clock to "
"%d-%02d-%02d %02d:%02d:%02d UTC (%lld)\n",
tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
tm.tm_hour, tm.tm_min, tm.tm_sec,
(long long) tv64.tv_sec);
err_read:
rtc_class_close(rtc);
err_open:
rtc_hctosys_ret = err;
return err;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| alessandro zummo | alessandro zummo | 105 | 61.05% | 1 | 11.11% |
| uwe kleine-koenig | uwe kleine-koenig | 41 | 23.84% | 1 | 11.11% |
| pang xunlei | pang xunlei | 13 | 7.56% | 1 | 11.11% |
| david brownell | david brownell | 9 | 5.23% | 3 | 33.33% |
| david fries | david fries | 2 | 1.16% | 1 | 11.11% |
| joe perches | joe perches | 1 | 0.58% | 1 | 11.11% |
| floris bos | floris bos | 1 | 0.58% | 1 | 11.11% |
| Total | 172 | 100.00% | 9 | 100.00% |
late_initcall(rtc_hctosys);
Overall Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| alessandro zummo | alessandro zummo | 115 | 60.85% | 1 | 11.11% |
| uwe kleine-koenig | uwe kleine-koenig | 41 | 21.69% | 1 | 11.11% |
| pang xunlei | pang xunlei | 13 | 6.88% | 1 | 11.11% |
| david brownell | david brownell | 9 | 4.76% | 3 | 33.33% |
| joe perches | joe perches | 8 | 4.23% | 1 | 11.11% |
| david fries | david fries | 2 | 1.06% | 1 | 11.11% |
| floris bos | floris bos | 1 | 0.53% | 1 | 11.11% |
| Total | 189 | 100.00% | 9 | 100.00% |
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