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authorXunlei Pang <pang.xunlei@linaro.org>2015-06-12 06:10:16 +0300
committerAlexandre Belloni <alexandre.belloni@free-electrons.com>2015-06-25 02:13:42 +0300
commit9c5150b31b49e3d89c52df9b1c1ebcea4e665ec3 (patch)
treebba4dff4be684e676b1a148ea7eca8393cb39efb /drivers/rtc/Kconfig
parent9033fd8ba7e96821e65fe3afc3f4077a8b66d1c9 (diff)
downloadlinux-9c5150b31b49e3d89c52df9b1c1ebcea4e665ec3.tar.xz
rtc: NTP: Add CONFIG_RTC_SYSTOHC_DEVICE for NTP synchronization
Currently, CONFIG_RTC_SYSTOHC uses CONFIG_RTC_HCTOSYS_DEVICE which is originally used by CONFIG_RTC_HCTOSYS, but this rtc device has some limiations, for example, it must be battery-backed, be able to work with irq off and through system suspension, etc. So add CONFIG_RTC_SYSTOHC_DEVICE used exclusively for CONFIG_RTC_SYSTOHC, it is more lenient compared to CONFIG_RTC_HCTOSYS_DEVICE, and could be assigned any available RTC in the system. Default value is CONFIG_RTC_HCTOSYS_DEVICE which is "rtc0" by default. After this patch, NTP will sync up "rtc0" by default. Cc: Paul Bolle <pebolle@tiscali.nl> Signed-off-by: Xunlei Pang <pang.xunlei@linaro.org> Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Diffstat (limited to 'drivers/rtc/Kconfig')
-rw-r--r--drivers/rtc/Kconfig29
1 files changed, 20 insertions, 9 deletions
diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index c94bb6aded51..efaff368ee94 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -25,17 +25,9 @@ config RTC_HCTOSYS
the value read from a specified RTC device. This is useful to avoid
unnecessary fsck runs at boot time, and to network better.
-config RTC_SYSTOHC
- bool "Set the RTC time based on NTP synchronization"
- default y
- 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
- minutes if userspace reports synchronized NTP status.
-
config RTC_HCTOSYS_DEVICE
string "RTC used to set the system time"
- depends on RTC_HCTOSYS = y || RTC_SYSTOHC = y
+ depends on RTC_HCTOSYS
default "rtc0"
help
The RTC device that will be used to (re)initialize the system
@@ -56,6 +48,25 @@ config RTC_HCTOSYS_DEVICE
sleep states. Do not specify an RTC here unless it stays powered
during all this system's supported sleep states.
+config RTC_SYSTOHC
+ bool "Set the RTC time based on NTP synchronization"
+ default y
+ 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
+ minutes if userspace reports synchronized NTP status.
+
+config RTC_SYSTOHC_DEVICE
+ string "RTC used to synchronize NTP adjustment"
+ depends on RTC_SYSTOHC
+ default RTC_HCTOSYS_DEVICE if RTC_HCTOSYS
+ default "rtc0"
+ help
+ The RTC device used for NTP synchronization. The main difference
+ between RTC_HCTOSYS_DEVICE and RTC_SYSTOHC_DEVICE is that this
+ one can sleep when setting time, because it runs in the workqueue
+ context.
+
config RTC_DEBUG
bool "RTC debug support"
help