the epoch by default, or if there's a leading +, seconds in the
future, or if there is a leading +=, seconds ahead of the current
alarm.
+offset: The amount which the rtc clock has been adjusted in firmware.
+ Visible only if the driver supports clock offset adjustment.
+ The unit is parts per billion, i.e. The number of clock ticks
+ which are added to or removed from the rtc's base clock per
+ billion ticks. A positive value makes a day pass more slowly,
+ longer, and a negative value makes a day pass more quickly.
IOCTL INTERFACE
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