Merge branch 'for-linus' of git://git.kernel.dk/linux-block
[linux-2.6-block.git] / Documentation / ABI / testing / sysfs-class-rtc-rtc0-device-rtc_calibration
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aaa6f6ac 1What: /sys/class/rtc/rtc0/device/rtc_calibration
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2Date: Oct 2011
3KernelVersion: 3.0
4Contact: Mark Godfrey <mark.godfrey@stericsson.com>
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5Description: Attribute for calibrating ST-Ericsson AB8500 Real Time Clock
6 The rtc_calibration attribute allows the userspace to
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7 calibrate the AB8500.s 32KHz Real Time Clock.
8 Every 60 seconds the AB8500 will correct the RTC's value
9 by adding to it the value of this attribute.
10 The range of the attribute is -127 to +127 in units of
11 30.5 micro-seconds (half-parts-per-million of the 32KHz clock)
12Users: The /vendor/st-ericsson/base_utilities/core/rtc_calibration
13 daemon uses this interface.