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| author | Mark Godfrey <mark.godfrey@stericsson.com> | 2012-01-10 15:10:42 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-01-10 16:30:52 -0800 |
| commit | dda367ac064d7473d397b1965019fb3be7cfb6b0 (patch) | |
| tree | 332b14ebfc6340c6941be7ec64250093ee631f3d /Documentation | |
| parent | 012e52e15e7ebbc7b08165e8f4b10f71a3e6810b (diff) | |
| download | lwn-dda367ac064d7473d397b1965019fb3be7cfb6b0.tar.gz lwn-dda367ac064d7473d397b1965019fb3be7cfb6b0.zip | |
rtc/ab8500: add calibration attribute to AB8500 RTC
The rtc_calibration attribute allows user-space to get and set the
AB8500's RtcCalibration register. The AB8500 will then use the value in
this register to compensate for RTC drift every 60 seconds.
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Mark Godfrey <mark.godfrey@stericsson.com>
Signed-off-by: Linus Walleij <linus.walleij@stericsson.com>
Acked-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
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/ABI/testing/sysfs-class-rtc-rtc0-device-rtc_calibration | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-class-rtc-rtc0-device-rtc_calibration b/Documentation/ABI/testing/sysfs-class-rtc-rtc0-device-rtc_calibration new file mode 100644 index 000000000000..4cf1e72222d9 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-class-rtc-rtc0-device-rtc_calibration @@ -0,0 +1,12 @@ +What: Attribute for calibrating ST-Ericsson AB8500 Real Time Clock +Date: Oct 2011 +KernelVersion: 3.0 +Contact: Mark Godfrey <mark.godfrey@stericsson.com> +Description: The rtc_calibration attribute allows the userspace to + calibrate the AB8500.s 32KHz Real Time Clock. + Every 60 seconds the AB8500 will correct the RTC's value + by adding to it the value of this attribute. + The range of the attribute is -127 to +127 in units of + 30.5 micro-seconds (half-parts-per-million of the 32KHz clock) +Users: The /vendor/st-ericsson/base_utilities/core/rtc_calibration + daemon uses this interface. |