xref: /linux/Documentation/ABI/testing/sysfs-class-rtc-rtc0-device-rtc_calibration (revision dda367ac064d7473d397b1965019fb3be7cfb6b0) 
1*dda367acSMark GodfreyWhat:           Attribute for calibrating ST-Ericsson AB8500 Real Time Clock
2*dda367acSMark GodfreyDate:           Oct 2011
3*dda367acSMark GodfreyKernelVersion:  3.0
4*dda367acSMark GodfreyContact:        Mark Godfrey <mark.godfrey@stericsson.com>
5*dda367acSMark GodfreyDescription:    The rtc_calibration attribute allows the userspace to
6*dda367acSMark Godfrey                calibrate the AB8500.s 32KHz Real Time Clock.
7*dda367acSMark Godfrey                Every 60 seconds the AB8500 will correct the RTC's value
8*dda367acSMark Godfrey                by adding to it the value of this attribute.
9*dda367acSMark Godfrey                The range of the attribute is -127 to +127 in units of
10*dda367acSMark Godfrey                30.5 micro-seconds (half-parts-per-million of the 32KHz clock)
11*dda367acSMark GodfreyUsers:          The /vendor/st-ericsson/base_utilities/core/rtc_calibration
12*dda367acSMark Godfrey                daemon uses this interface.
13