Commit-ID: 05ad717c77b1b8e98a1dd768c3700036d634629e
Gitweb: http://git.kernel.org/tip/05ad717c77b1b8e98a1dd768c3700036d634629e
Author: Feng Tang <feng.tang@xxxxxxxxx>
AuthorDate: Wed, 16 Jan 2013 00:09:49 +0800
Committer: John Stultz <john.stultz@xxxxxxxxxx>
CommitDate: Tue, 15 Jan 2013 18:16:08 -0800
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@xxxxxxxxxxxxx>
Suggested-by: John Stultz <john.stultz@xxxxxxxxxx>
Signed-off-by: Feng Tang <feng.tang@xxxxxxxxx>
[jstultz: Added dependency for RTC_SYSTOHC as well]
Signed-off-by: John Stultz <john.stultz@xxxxxxxxxx>
---
drivers/rtc/Kconfig | 2 ++
include/linux/time.h | 5 +++++
kernel/time/Kconfig | 5 +++++
3 files changed, 12 insertions(+)
diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index b377e96..05761de 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 dfbc4e8..369b6e3 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 8601f0d..f7e45b9 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
--
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