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+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.