timekeeping: Add CONFIG_HAS_PERSISTENT_CLOCK option

Make the persistent clock check a kernel config option, so that some
platform can explicitely select it, also make CONFIG_RTC_HCTOSYS and
RTC_SYSTOHC depend on its non-existence, which could prevent the
persistent clock and RTC code from doing similar thing twice during
system's init/suspend/resume phases.

If the CONFIG_HAS_PERSISTENT_CLOCK=n, then no change happens for kernel
which still does the persistent clock check in timekeeping_init().

Cc: Thomas Gleixner <tglx@linutronix.de>
Suggested-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Feng Tang <feng.tang@intel.com>
[jstultz: Added dependency for RTC_SYSTOHC as well]
Signed-off-by: John Stultz <john.stultz@linaro.org>
This commit is contained in:
Feng Tang 2013-01-16 00:09:49 +08:00 committed by John Stultz
parent 9ecf37eb7a
commit 05ad717c77
3 changed files with 12 additions and 0 deletions

View file

@ -116,10 +116,15 @@ static inline bool timespec_valid_strict(const struct timespec *ts)
}
extern bool persistent_clock_exist;
#ifdef CONFIG_HAS_PERSISTENT_CLOCK
#define has_persistent_clock() true
#else
static inline bool has_persistent_clock(void)
{
return persistent_clock_exist;
}
#endif
extern void read_persistent_clock(struct timespec *ts);
extern void read_boot_clock(struct timespec *ts);