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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>
This commit is contained in:
Xunlei Pang 2015-06-12 11:10:16 +08:00 committed by Alexandre Belloni
parent 9033fd8ba7
commit 9c5150b31b
2 changed files with 21 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

29
drivers/rtc/Kconfig
View File

@ -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

2
drivers/rtc/systohc.c
View File

@ -31,7 +31,7 @@ int rtc_set_ntp_time(struct timespec64 now)
else
rtc_time64_to_tm(now.tv_sec + 1, &tm);
rtc = rtc_class_open(CONFIG_RTC_HCTOSYS_DEVICE);
rtc = rtc_class_open(CONFIG_RTC_SYSTOHC_DEVICE);
if (rtc) {
/* rtc_hctosys exclusively uses UTC, so we call set_time here,
* not set_mmss. */