From 023f333a99cee9b5cd3268ff87298eb01a31f78e Mon Sep 17 00:00:00 2001 From: Jason Gunthorpe Date: Mon, 17 Dec 2012 14:30:53 -0700 Subject: NTP: Add a CONFIG_RTC_SYSTOHC configuration 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 Signed-off-by: John Stultz --- drivers/rtc/Kconfig | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) (limited to 'drivers/rtc/Kconfig') diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig index 19c03ab2bdcb..b377e9672497 100644 --- a/drivers/rtc/Kconfig +++ b/drivers/rtc/Kconfig @@ -25,9 +25,17 @@ config RTC_HCTOSYS the value read from a specified RTC device. This is useful to avoid unnecessary fsck runs at boot time, and to network better. +config RTC_SYSTOHC + bool "Set the RTC time based on NTP synchronization" + default y + help + If you say yes here, the system time (wall clock) will be stored + in the RTC specified by RTC_HCTOSYS_DEVICE approximately every 11 + minutes if userspace reports synchronized NTP status. + config RTC_HCTOSYS_DEVICE string "RTC used to set the system time" - depends on RTC_HCTOSYS = y + depends on RTC_HCTOSYS = y || RTC_SYSTOHC = y default "rtc0" help The RTC device that will be used to (re)initialize the system -- cgit v1.2.3