linux-kernel - Re: [rtc-linux] Re: [PATCH/RFC 0/5] Generic RTC class driver

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Message-ID: <20090223160506.04e347c7@i1501.lan.towertech.it>
Date:	Mon, 23 Feb 2009 16:05:06 +0100
From:	Alessandro Zummo <alessandro.zummo@...ertech.it>
To:	rtc-linux@...glegroups.com
Cc:	Geert.Uytterhoeven@...ycom.com,
	Richard Zidlicky <rz@...ux-m68k.org>,
	linux-parisc@...r.kernel.org,
	Linux Kernel Development <linux-kernel@...r.kernel.org>,
	David@...abs.org, Kyle McMartin <kyle@...artin.ca>,
	Linux/PPC Development <linuxppc-dev@...abs.org>,
	Linux/m68k <linux-m68k@...ts.linux-m68k.org>,
	Woodhouse <dwmw2@...radead.org>,
	Benjamin Herrenschmidt <benh@...nel.crashing.org>
Subject: Re: [rtc-linux] Re: [PATCH/RFC 0/5] Generic RTC class driver

On Mon, 23 Feb 2009 13:34:49 +0100 (CET)
Geert Uytterhoeven <Geert.Uytterhoeven@...ycom.com> wrote:

> >  Hello,
> > 
> >    my opinion on this kind of stuff is that I want to avoid the layering
> >  of implementations under the rtc subsystem. I'd rather prefer that each
> >  rtc device had its own driver. 
> >  
> >   I've made error in the past, by accepting such kind of drivers, and
> >  would like to avoid that it happens again.
> 
> So you want us to kill the ppc_md.[gs]et_rtc_time() [ppc], mach_hwclk() [m68k],
> mach_gettod() [m68knommu] (and probably a few other) abstractions, and move all
> RTC code out of arch/ into seperate drivers under drivers/rtc/ instead?

 not all at once :) 

 I'd start writing a working driver and then see how we should eventually
 adapt the rtc subsystem to cope with your needs.
 
> What about ppc_md.get_boot_time() [ppc]?
> Please note that the functions above may also be used for very early clock
> setting (e.g. time_init()) and in read_persistent_clock().
> How should we handle these?

 read_persistent_clock is something that should be reconsidered
 as well along with all the ntp stuff.

> Even on x86 there seems to be way too much RTC logic in arch/x86/kernel/rtc.c

> (e.g. mach_get_cmos_time()), which is duplicated in drivers/rtc/rtc-cmos.c
> through the inline function __get_rtc_time() in include/asm-generic/rtc.h
> (clever, hardware-specific stuff in asm-generic ;-)

 yep, I know :( that hardcoded rtc stuff seems to be everywhere!


-- 

 Best regards,

 Alessandro Zummo,
  Tower Technologies - Torino, Italy

  http://www.towertech.it

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