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authorMatthew Garrett <mjg59@srcf.ucam.org>2009-09-22 19:46:32 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2009-09-23 10:39:46 -0400
commitd8c1acb1664d17dd995e34507533321e986d9215 (patch)
tree5c8c8a60bc0da9f16a748c6ef8c3cb98f33d21be /Documentation
parentea3d1606fd32059461309099e8856c6652888a79 (diff)
rtc: add boot_timesource sysfs attribute
CONFIG_RTC_HCTOSYS allows the kernel to read the system time from the RTC at boot and resume, avoiding the need for userspace to do so. Unfortunately userspace currently has no way to know whether this configuration option is enabled and thus cannot sensibly choose whether to run hwclock itself or not. Add a hctosys sysfs attribute which indicates whether a given RTC set the system clock. Signed-off-by: Matthew Garrett <mjg@redhat.com> Acked-by: Alessandro Zummo <a.zummo@towertech.it> Cc: Mark Brown <broonie@opensource.wolfsonmicro.com> Cc: David Brownell <david-b@pacbell.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/rtc.txt2
1 files changed, 2 insertions, 0 deletions
diff --git a/Documentation/rtc.txt b/Documentation/rtc.txt
index 2745e8197fde..9104c1062084 100644
--- a/Documentation/rtc.txt
+++ b/Documentation/rtc.txt
@@ -143,6 +143,8 @@ rtc attributes without requiring the use of ioctls. All dates and times
143are in the RTC's timezone, rather than in system time. 143are in the RTC's timezone, rather than in system time.
144 144
145date: RTC-provided date 145date: RTC-provided date
146hctosys: 1 if the RTC provided the system time at boot via the
147 CONFIG_RTC_HCTOSYS kernel option, 0 otherwise
146max_user_freq: The maximum interrupt rate an unprivileged user may request 148max_user_freq: The maximum interrupt rate an unprivileged user may request
147 from this RTC. 149 from this RTC.
148name: The name of the RTC corresponding to this sysfs directory 150name: The name of the RTC corresponding to this sysfs directory