linux-kernel - Re: [PATCH 0/2 v3] Add pl031 RTC support for Hi6220

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Date:	Wed, 6 Jul 2016 17:19:53 -0700
From:	Michael Turquette <mturquette@...libre.com>
To:	Arnd Bergmann <arnd@...db.de>
Cc:	John Stultz <john.stultz@...aro.org>,
	Olof Johansson <olof@...om.net>,
	lkml <linux-kernel@...r.kernel.org>,
	"arm@...nel.org" <arm@...nel.org>,
	Stephen Boyd <sboyd@...eaurora.org>,
	Rob Herring <robh+dt@...nel.org>,
	Pawel Moll <pawel.moll@....com>, Wei Xu <xuwei5@...ilicon.com>,
	Guodong Xu <guodong.xu@...aro.org>,
	Zhangfei Gao <zhangfei.gao@...aro.org>
Subject: Re: [PATCH 0/2 v3] Add pl031 RTC support for Hi6220

Hi!

On Wed, Jul 6, 2016 at 12:38 AM, Arnd Bergmann <arnd@...db.de> wrote:
>
> On Wednesday, July 6, 2016 12:20:15 AM CEST John Stultz wrote:
> > On Wed, Jul 6, 2016 at 12:04 AM, Olof Johansson <olof@...om.net> wrote:
> > > On Tue, Jul 5, 2016 at 11:55 PM, John Stultz <john.stultz@...aro.org> wrote:
> > >> On Tue, Jul 5, 2016 at 10:22 PM, Olof Johansson <olof@...om.net> wrote:
> > >>> On Wed, Jun 29, 2016 at 05:48:43PM -0700, John Stultz wrote:
> > >>>> This patchset enables the pl031 RTC on the Hi6220 SoC.
> > >>>>
> > >>>> I'd like to submit it to be merged.
> > >>>>
> > >>>> Wei has acked the second patch (modulo a whitespace fix which
> > >>>> I've included in this v3), so it seems like both could go
> > >>>> through the clk tree.
> > >>>>
> > >>>> But Wei also seemed open to pulling in a clk tree branch
> > >>>> as it goes through arm-soc.
> > >>>>
> > >>>> Michael/Stephen: If there's no other objections, could you
> > >>>> queue the first patch and make it avilable via the branch for
> > >>>> Wei, or just take both patches?
> > >>>
> > >>> I happen to dread these kind of patchsets these days. There's added
> > >>> dependencies across trees just because a defined name for the clock
> > >>> number is added to a header file.
> > >>>
> > >>> I much prefer to use numerical clocks for one release, and then once
> > >>> everything is in, switch over to the defines in the DTS.
> > >>>
> > >>> That way there are no dependencies, no need to setup a shared branch
> > >>> for a simple 3-line patch, etc.
> > >>>
> > >>> So, mind respinning the DTS piece?
> > >>
> > >> Huh..
> > >
> > > Sorry if it appeared random, I've complained about it for a while to
> > > submaintainers.
> >
> > No.. I get it, the cross-maintainer shared branch is complex enough to
> > want to avoid. I figured it would be easier to just take a maintainer
> > acked patch in via the clk tree, but its not my tree, so I'll leave it
> > to you maintainers to resolve.
>
> The question this raises is why that clock was missed the first time
> around. I'd suggest whoever owns the clock driver can go through the
> documentation again and look for others that may have been missed,
> then send a patch to the driver to add *all* the missing ones for the
> merge window, and one release later we add the driver depending on
> previously unknown clocks.

Well, I'm kicking the ant pile on this one, but sometimes the above
suggestion is not possible. I'm currently hacking on a platform with
very limited docs, so I cannot understand the whole clock tree, nor
how all peripherals are wired up to it.

Further complicating matters is that fact that any headers in the DT
include chroot constitute an unbreakable ABI that shall stand for
1,000 years at least, so I'm very remiss to dump a bunch of constant
values in there with names that might need to change at a later date.

Thoughts?

Regards,
Mike

>
>         Arnd




-- 
Michael Turquette
CEO
BayLibre - At the Heart of Embedded Linux
http://baylibre.com/