summaryrefslogtreecommitdiffstats
path: root/drivers/rtc/systohc.c
AgeCommit message (Collapse)AuthorFilesLines
2018-03-27rtc: remove a warning during scripts/kernel-doc stepMathieu Malaterre1-1/+1
During compilation using W=1 one would get: drivers/rtc/systohc.c:11: info: Scanning doc for rtc_set_ntp_time drivers/rtc/systohc.c:23: warning: bad line: ( Signed-off-by: Mathieu Malaterre <malat@debian.org> Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
2017-10-30rtc: Allow rtc drivers to specify the tv_nsec value for ntpJason Gunthorpe1-15/+38
ntp is currently hardwired to try and call the rtc set when wall clock tv_nsec is 0.5 seconds. This historical behaviour works well with certain PC RTCs, but is not universal to all rtc hardware. Change how this works by introducing the driver specific concept of set_offset_nsec, the delay between current wall clock time and the target time to set (with a 0 tv_nsecs). For x86-style CMOS set_offset_nsec should be -0.5 s which causes the last second to be written 0.5 s after it has started. For compat with the old rtc_set_ntp_time, the value is defaulted to + 0.5 s, which causes the next second to be written 0.5s before it starts, as things were before this patch. Testing shows many non-x86 RTCs would like set_offset_nsec ~= 0, so ultimately each RTC driver should set the set_offset_nsec according to its needs, and non x86 architectures should stop using update_persistent_clock64 in order to access this feature. Future patches will revise the drivers as needed. Since CMOS and RTC now have very different handling they are split into two dedicated code paths, sharing the support code, and ifdefs are replaced with IS_ENABLED. Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@kernel.org> Cc: Miroslav Lichvar <mlichvar@redhat.com> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Stephen Boyd <stephen.boyd@linaro.org> Signed-off-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com> Signed-off-by: John Stultz <john.stultz@linaro.org>
2015-06-25rtc: NTP: Add CONFIG_RTC_SYSTOHC_DEVICE for NTP synchronizationXunlei Pang1-1/+1
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>
2015-04-03drivers/rtc: Provide y2038 safe rtc_class_ops.set_mmss() replacementXunlei Pang1-1/+4
Currently the rtc_class_op's set_mmss() function takes a 32-bit second value (on 32-bit systems), which is problematic for dates past y2038. This patch provides a safe version named set_mmss64() using y2038 safe time64_t. After this patch, set_mmss() is deprecated and all its users will be fixed to use set_mmss64(), it can be removed when having no users. Signed-off-by: Xunlei Pang <pang.xunlei@linaro.org> [jstultz: Add whitespace fix for checkpatch] Signed-off-by: John Stultz <john.stultz@linaro.org> Acked-by: Alessandro Zummo <a.zummo@towertech.it> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1427945681-29972-8-git-send-email-john.stultz@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-04-03time: Add y2038 safe update_persistent_clock64()Xunlei Pang1-1/+1
As part of addressing in-kernel y2038 issues, this patch adds update_persistent_clock64() and replaces all the call sites of update_persistent_clock() with this function. This is a __weak implementation, which simply calls the existing y2038 unsafe update_persistent_clock(). This allows architecture specific implementations to be converted independently, and eventually y2038-unsafe update_persistent_clock() can be removed after all its architecture specific implementations have been converted to update_persistent_clock64(). Suggested-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Xunlei Pang <pang.xunlei@linaro.org> Signed-off-by: John Stultz <john.stultz@linaro.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1427945681-29972-4-git-send-email-john.stultz@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-01-23rtc: Convert rtc_set_ntp_time() to use timespec64Xunlei Pang1-3/+3
rtc_set_ntp_time() uses timespec which is y2038-unsafe, so modify to use timespec64 which is y2038-safe, then replace rtc_time_to_tm() with rtc_time64_to_tm(). Also adjust all its call sites(only NTP uses it) accordingly. Cc: pang.xunlei <pang.xunlei@linaro.org> Cc: Arnd Bergmann <arnd.bergmann@linaro.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@kernel.org> Signed-off-by: Xunlei Pang <pang.xunlei@linaro.org> Signed-off-by: John Stultz <john.stultz@linaro.org>
2013-01-15NTP: Add a CONFIG_RTC_SYSTOHC configurationJason Gunthorpe1-0/+44
The purpose of this option is to allow ARM/etc systems that rely on the class RTC subsystem to have the same kind of automatic NTP based synchronization that we have on PC platforms. Today ARM does not implement update_persistent_clock and makes extensive use of the class RTC system. When enabled CONFIG_RTC_SYSTOHC will provide a generic rtc_update_persistent_clock that stores the current time in the RTC and is intended complement the existing CONFIG_RTC_HCTOSYS option that loads the RTC at boot. Like with RTC_HCTOSYS the platform's update_persistent_clock is used first, if it works. Platforms with mixed class RTC and non-RTC drivers need to return ENODEV when class RTC should be used. Such an update for PPC is included in this patch. Long term, implementations of update_persistent_clock should migrate to proper class RTC drivers and use CONFIG_RTC_SYSTOHC instead. Tested on ARM kirkwood and PPC405 Signed-off-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com> Signed-off-by: John Stultz <john.stultz@linaro.org>