diff options
| author | Feng Tang <feng.tang@intel.com> | 2013-01-16 00:09:49 +0800 |
|---|---|---|
| committer | John Stultz <john.stultz@linaro.org> | 2013-01-15 18:16:08 -0800 |
| commit | 05ad717c77b1b8e98a1dd768c3700036d634629e (patch) | |
| tree | c52d75ca925bcd9b4c7125aad4c1059d7d3a43ee | |
| parent | 9ecf37eb7a81e3295a1b274eafb6f83d7d2cabf0 (diff) | |
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>
| -rw-r--r-- | drivers/rtc/Kconfig | 2 | ||||
| -rw-r--r-- | include/linux/time.h | 5 | ||||
| -rw-r--r-- | kernel/time/Kconfig | 5 |
3 files changed, 12 insertions, 0 deletions
diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig index b377e9672497..05761de7929b 100644 --- a/drivers/rtc/Kconfig +++ b/drivers/rtc/Kconfig @@ -20,6 +20,7 @@ if RTC_CLASS config RTC_HCTOSYS bool "Set system time from RTC on startup and resume" default y + depends on !HAS_PERSISTENT_CLOCK help If you say yes here, the system time (wall clock) will be set using the value read from a specified RTC device. This is useful to avoid @@ -28,6 +29,7 @@ config RTC_HCTOSYS config RTC_SYSTOHC bool "Set the RTC time based on NTP synchronization" default y + depends on !HAS_PERSISTENT_CLOCK 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 diff --git a/include/linux/time.h b/include/linux/time.h index dfbc4e82e8ba..369b6e3b87d8 100644 --- a/include/linux/time.h +++ b/include/linux/time.h @@ -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); diff --git a/kernel/time/Kconfig b/kernel/time/Kconfig index 8601f0db1261..f7e45b9b142b 100644 --- a/kernel/time/Kconfig +++ b/kernel/time/Kconfig @@ -12,6 +12,11 @@ config CLOCKSOURCE_WATCHDOG config ARCH_CLOCKSOURCE_DATA bool +# Platforms has a persistent clock +config HAS_PERSISTENT_CLOCK + bool + default n + # Timekeeping vsyscall support config GENERIC_TIME_VSYSCALL bool |