linux-kernel - Re: [RESEND PATCH v4] clk: x86: Add Atom PMC platform clocks

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Message-ID: <20161026213323.GB23374@f23x64.localdomain>
Date:   Wed, 26 Oct 2016 14:33:23 -0700
From:   Darren Hart <dvhart@...radead.org>
To:     "Tirdea, Irina" <irina.tirdea@...el.com>
Cc:     Thomas Gleixner <tglx@...utronix.de>,
        "linux-clk@...r.kernel.org" <linux-clk@...r.kernel.org>,
        "x86@...nel.org" <x86@...nel.org>,
        Stephen Boyd <sboyd@...eaurora.org>,
        Ingo Molnar <mingo@...hat.com>,
        Michael Turquette <mturquette@...libre.com>,
        "H. Peter Anvin" <hpa@...or.com>,
        "alsa-devel@...a-project.org" <alsa-devel@...a-project.org>,
        Mark Brown <broonie@...nel.org>, Takashi Iwai <tiwai@...e.com>,
        "Bossart, Pierre-louis" <pierre-louis.bossart@...el.com>,
        LKML <linux-kernel@...r.kernel.org>,
        Pierre-Louis Bossart <pierre-louis.bossart@...ux.intel.com>
Subject: Re: [RESEND PATCH v4] clk: x86: Add Atom PMC platform clocks

On Mon, Oct 24, 2016 at 01:38:54PM +0000, Tirdea, Irina wrote:
> > On Thu, Oct 20, 2016 at 11:52:38PM +0200, Thomas Gleixner wrote:
> > > On Mon, 17 Oct 2016, Irina Tirdea wrote:
> > > > The patch has already been reviewed by Stephen Boyd [1].
> > > > The only remaining question is the one pointed out by Stephen:
> > > > "Will there be problems if this merges through clk tree? If so we
> > > > could take the clk driver part and the platform data include part
> > > > could be duplicated into both trees. Or clk tree could be pulled
> > > > into x86?" [1]
> > >
> > > The proper thing to do is:
> > >
> > > Move all that cruft including arch/x86/platform/atom/pmc_atom.c into
> > > drivers/platform/x86. There is nothing architecture specific in these
> > > files. It's pure peripheral driver enablement. So drivers/platform/x86 is
> > > the proper location for this. Please discuss this with Darren Hart (cc'ed).
> > 
> 
> Thanks for pointing me in the right direction, Thomas!
> 
> > We've been adding more of the pmc and punit drivers to drivers/platform/x86.
> > This makes more sense than being under "arch". Thomas and I have discussed
> > moving more of the non architectural stuff in arch/x86/platform to my tree under
> > platform/drivers/x86.
> > 
> 
> Thanks for the reply, Darren.
> 
> I could move the arch/x86/platform/atom/pmc_atom.c into drivers/platform/x86,
> but I'm not sure what the process is in this case. I took a look at your tree and noticed
> some intel_pmc_* drivers, but they are quite different from pmc_atom.c in terms of
> HW registers and capabilities. Should the code from pmc_atom.c be integrated in the
> intel_pmc_* drivers or is it enough to move it as a standalone driver for now?

If the functionality is substantially different, then I don't see a
compelling, and certainly not an immediate, need to merge them. Assume
for now they are to remain as separate drivers. I suggest keeping the
existing name for now as well. Let's just complete the move with as
little user-visible changes as possible.

The placement of the header file is a bit tricky as it is being used in
drivers/clk/x86 in addition to the pmc_atom driver in
drivers/platform/x86.

The best existing location would appear to be include/platform_data/

Thomas, is that acceptable to you?

arch/x86/platform/atom/pmc_atom.c -> drivers/platform/x86
arch/x86/include/asm/pmc_atom.h -> include/platform_data/

If there are enough of these, it might make sense to create:

include/platform/x86/

but I suggest we start with minimal change.

> 
> > Irina, please point me at the relevant context if it's more than just this
> > particular patch.
> 
> This patch comes from a set of patches that enable sound for Baytrail CR devices
> (especially Asus T100TAF) [1]. The rest of the patches have been already merged in
> Mark's sound tree. This is the only change remaining for enabling sound on these
> platforms, so there are no additional changes to the x86 platform code.
> 
> Thanks,
> Irina
> 
> [1] http://mailman.alsa-project.org/pipermail/alsa-devel/2016-August/111704.html
> 
> 

-- 
Darren Hart
Intel Open Source Technology Center