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    rtc: suspend()/resume() restores system clock · 7ca1d488
    David Brownell 提交于
    RTC class suspend/resume support, re-initializing the system clock on resume
    from the clock used to initialize it at boot time.
    
     - The reinit-on-resume is hooked to the existing RTC_HCTOSYS config
       option, on the grounds that a clock good enough for init must also
       be good enough for re-init.
    
     - Inlining a version of the code used by ARM, to save and restore the
       delta between a selected RTC and the current system wall-clock time.
    
     - Removes calls to that ARM code from AT91, OMAP1, and S3C RTCs.  This
       means that systems using those RTCs across suspend/resume will likely
       want to change their kernel configs to enable RTC_HCTOSYS.
    
       If HCTOSYS isn't using a second RTC (with battery?), this changes the
       system's initial date from Jan 1970 to the epoch this hardware uses:
       1998 for AT91, 2000 for OMAP1 (assuming no split power mode), etc.
    
    This goes on top of the patch series removing "struct class_device" usage
    from the RTC framework.  That's all needed for class suspend()/resume().
    Signed-off-by: NDavid Brownell <dbrownell@users.sourceforge.net>
    Acked-by: NGreg Kroah-Hartman <gregkh@suse.de>
    Acked-By: NAlessandro Zummo <a.zummo@towertech.it>
    Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
    7ca1d488
Kconfig 11.7 KB