linux-hardened/drivers/rtc/hctosys.c
Linus Torvalds 28e8c4bc8e RTC for 4.21
Subsystem:
  - new %ptR printk format
  - rename core files
  - allow registration of multiple nvmem devices
 
 New driver:
  - i.MX system controller RTC
 
 Drivers:
  - abx80x: handle voltage ioctls, correct binding doc
  - m41t80: correct month in alarm reads
  - pcf85363: add pcf85263 support
  - pcf8523: properly handle battery low flag
  - s3c: limit alarm to one year in the future as ALMYEAR is broken
  - sun6i: rework clock output binding
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Merge tag 'rtc-4.21' of git://git.kernel.org/pub/scm/linux/kernel/git/abelloni/linux

Pull RTC updates from Alexandre Belloni:
 "Subsystem:
   - new %ptR printk format
   - rename core files
   - allow registration of multiple nvmem devices

  New driver:
   - i.MX system controller RTC

  Driver updates:
   - abx80x: handle voltage ioctls, correct binding doc
   - m41t80: correct month in alarm reads
   - pcf85363: add pcf85263 support
   - pcf8523: properly handle battery low flag
   - s3c: limit alarm to one year in the future as ALMYEAR is broken
   - sun6i: rework clock output binding"

* tag 'rtc-4.21' of git://git.kernel.org/pub/scm/linux/kernel/git/abelloni/linux: (54 commits)
  rtc: rename core files
  rtc: nvmem: fix possible use after free
  rtc: add i.MX system controller RTC support
  dt-bindings: fsl: scu: add rtc binding
  rtc: pcf2123: Add Microcrystal rv2123
  rtc: class: reimplement devm_rtc_device_register
  rtc: enforce rtc_timer_init private_data type
  rtc: abx80x: Implement RTC_VL_READ,CLR ioctls
  rtc: pcf85363: Add support for NXP pcf85263 rtc
  dt-bindings: rtc: pcf85363: Document pcf85263 real-time clock
  rtc: pcf8523: don't return invalid date when battery is low
  dt-bindings: rtc: use a generic node name for ds1307
  PM: Switch to use %ptR
  m68k/mac: Switch to use %ptR
  Input: hp_sdc_rtc - Switch to use %ptR
  rtc: tegra: Switch to use %ptR
  rtc: s5m: Switch to use %ptR
  rtc: s3c: Switch to use %ptR
  rtc: rx8025: Switch to use %ptR
  rtc: rx6110: Switch to use %ptR
  ...
2019-01-01 13:24:31 -08:00

73 lines
1.8 KiB
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);
#if BITS_PER_LONG == 32
if (tv64.tv_sec > INT_MAX) {
err = -ERANGE;
goto err_read;
}
#endif
err = do_settimeofday64(&tv64);
dev_info(rtc->dev.parent, "setting system clock to %ptR UTC (%lld)\n",
&tm, (long long)tv64.tv_sec);
err_read:
rtc_class_close(rtc);
err_open:
rtc_hctosys_ret = err;
return err;
}
late_initcall(rtc_hctosys);