Re: Periodic RTC interrupt

From: Ralf Baechle (ralf@uni-koblenz.de)
Date: Sat Feb 19 2000 - 20:56:43 EST


On Sat, Feb 19, 2000 at 08:38:17PM -0500, Jeff Garzik wrote:

> > What application need the /dev/rtc periodic interrupt? I'm porting to
> > a platoform which uses a M58T35 RTC which doesn't supply such an
> > interrupt, so the question is if it's worth to care at all and possibly
> > emulate an timer interrupt from another source.
>
> The RTC driver doesn't make much sense without interrupts... look at
> the API in include/linux/rtc.h. Without interrupts, you are just
> querying the RTC status, which (I am guessing) is different on the
> M58T35.
>
> So, with no interrupts and a different status byte output, it sounds
> like a completely new chrdev driver to me... :)
>
> BTW, Andrea, since I think (???) this was your patch, why do you disable
> RTC interrupt on Alpha platform? You might as well disable the entire
> driver at that point IMHO...

/dev/rtc still makes sense as the interface for setting the clock. The
old way of directly accessing the hardware as done in clock(8) is a
completly unportable mess.

And then there is still /proc/rtc but that is more a toy for the
voyeuristic user :-)

  Ralf

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