From dda367ac064d7473d397b1965019fb3be7cfb6b0 Mon Sep 17 00:00:00 2001 From: Mark Godfrey Date: Tue, 10 Jan 2012 15:10:42 -0800 Subject: 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 Signed-off-by: Linus Walleij Acked-by: Jean-Christophe PLAGNIOL-VILLARD Cc: Alessandro Zummo Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- .../ABI/testing/sysfs-class-rtc-rtc0-device-rtc_calibration | 12 ++++++++++++ 1 file changed, 12 insertions(+) create mode 100644 Documentation/ABI/testing/sysfs-class-rtc-rtc0-device-rtc_calibration (limited to 'Documentation/ABI') 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 00000000000..4cf1e72222d --- /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 +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. -- cgit v1.2.3-18-g5258