Re: RTC subsystem and fractions of seconds

From: David Brownell
Date: Sun Jan 07 2007 - 21:31:45 EST


On Sunday 07 January 2007 2:14 am, Philippe De Muyter wrote:
> On Fri, Jan 05, 2007 at 07:49:00PM -0800, David Brownell wrote:
> > > Those rtc's actually have a 1/100th of second
> > > register. Should the generic rtc interface not support that?
> >
> > Are you implying a new userspace API, or just an in-kernel update?
> >
> > Either way, that raises the question of what other features should
> > be included. What sub-second precision? Multiple alarms? Ways
> > to manage output clocks? Sub-HZ periodic alarms?
>
> One usefull addition for my needs and with a m41t81 is the support of
> the calibration of the rtc. However this can perhaps be hidden in the
> .set_mmss function.

Doesn't seem like an set_mmss() mechanism at all. Some drivers give
sysfs access to an oscillator "trim" mechanism. What tools do you
have which track how far off that crystal is?

- Dave
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