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https://github.com/torvalds/linux
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9c5150b31b
Currently, CONFIG_RTC_SYSTOHC uses CONFIG_RTC_HCTOSYS_DEVICE which is originally used by CONFIG_RTC_HCTOSYS, but this rtc device has some limiations, for example, it must be battery-backed, be able to work with irq off and through system suspension, etc. So add CONFIG_RTC_SYSTOHC_DEVICE used exclusively for CONFIG_RTC_SYSTOHC, it is more lenient compared to CONFIG_RTC_HCTOSYS_DEVICE, and could be assigned any available RTC in the system. Default value is CONFIG_RTC_HCTOSYS_DEVICE which is "rtc0" by default. After this patch, NTP will sync up "rtc0" by default. Cc: Paul Bolle <pebolle@tiscali.nl> Signed-off-by: Xunlei Pang <pang.xunlei@linaro.org> Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
47 lines
1.2 KiB
C
47 lines
1.2 KiB
C
/*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 as published by
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* the Free Software Foundation.
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*
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*/
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#include <linux/rtc.h>
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#include <linux/time.h>
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/**
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* rtc_set_ntp_time - Save NTP synchronized time to the RTC
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* @now: Current time of day
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*
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* Replacement for the NTP platform function update_persistent_clock64
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* that stores time for later retrieval by rtc_hctosys.
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*
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* Returns 0 on successful RTC update, -ENODEV if a RTC update is not
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* possible at all, and various other -errno for specific temporary failure
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* cases.
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*
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* If temporary failure is indicated the caller should try again 'soon'
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*/
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int rtc_set_ntp_time(struct timespec64 now)
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{
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struct rtc_device *rtc;
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struct rtc_time tm;
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int err = -ENODEV;
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if (now.tv_nsec < (NSEC_PER_SEC >> 1))
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rtc_time64_to_tm(now.tv_sec, &tm);
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else
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rtc_time64_to_tm(now.tv_sec + 1, &tm);
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rtc = rtc_class_open(CONFIG_RTC_SYSTOHC_DEVICE);
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if (rtc) {
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/* rtc_hctosys exclusively uses UTC, so we call set_time here,
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* not set_mmss. */
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if (rtc->ops &&
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(rtc->ops->set_time ||
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rtc->ops->set_mmss64 ||
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rtc->ops->set_mmss))
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err = rtc_set_time(rtc, &tm);
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rtc_class_close(rtc);
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}
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return err;
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}
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