Re: [PATCH 1/2] RTC: rtc-cmos: drivers/char/rtc.c features for DECstation support

[Joshua Kinard <kumba@gentoo.org>]

On 04/19/2014 18:58, Maciej W. Rozycki wrote:
> This brings in drivers/char/rtc.c functionality required for DECstation 
> and, should the maintainers decide to switch, Alpha systems to use 
> rtc-cmos.
> 
> Specifically these features are made available:
> 
[snip]
> * The ability to use the RTC periodic interrupt as a system clock device,
>   which is implemented by arch/mips/kernel/cevt-ds1287.c for DECstation 
>   systems and takes the RTC interrupt away from the RTC driver.  
>   Eventually hooking back to the clock device's interrupt handler should 
>   be possible for the purpose of the alarm clock and possibly also 
>   update-in-progress interrupt, but this is not done by this change.

I had this implemented myself in the DS1685 driver I've still yet to send in
(for SGI IP32).  But the upper-level RTC code for periodic and update
interrupts was removed sometime between 2.6.39 and 3.0 and uses the kernel's
hrtimers to replace it.  No idea if they'll ever re-add that code for RTC
drivers that can use the hardware implementation instead.

-- 
Joshua Kinard
Gentoo/MIPS
kumba@gentoo.org
4096R/D25D95E3 2011-03-28

"The past tempts us, the present confuses us, the future frightens us.  And
our lives slip away, moment by moment, lost in that vast, terrible in-between."

--Emperor Turhan, Centauri Republic