• Jason Gunthorpe's avatar
    NTP: Add a CONFIG_RTC_SYSTOHC configuration · 023f333a
    Jason Gunthorpe authored
    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: default avatarJason Gunthorpe <jgunthorpe@obsidianresearch.com>
    Signed-off-by: default avatarJohn Stultz <john.stultz@linaro.org>
    023f333a
systohc.c 1.19 KB