linux-kernel - Re: [alsa-devel] [PATCH v6 1/3] clk: x86: Add Atom PMC platform clocks

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Date:   Fri, 16 Dec 2016 10:46:11 +0200
From:   Andy Shevchenko <andy.shevchenko@...il.com>
To:     Pierre-Louis Bossart <pierre-louis.bossart@...ux.intel.com>
Cc:     Stephen Boyd <sboyd@...eaurora.org>,
        ALSA Development Mailing List <alsa-devel@...a-project.org>,
        Irina Tirdea <irina.tirdea@...el.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Michael Turquette <mturquette@...libre.com>,
        "x86@...nel.org" <x86@...nel.org>,
        "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Takashi Iwai <tiwai@...e.com>,
        platform-driver-x86@...r.kernel.org,
        "linux-acpi@...r.kernel.org" <linux-acpi@...r.kernel.org>,
        Ingo Molnar <mingo@...hat.com>,
        Mark Brown <broonie@...nel.org>,
        "H. Peter Anvin" <hpa@...or.com>,
        Darren Hart <dvhart@...radead.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Len Brown <lenb@...nel.org>, linux-clk@...r.kernel.org,
        Pierre-Louis Bossart <pierre-louis.bossart@...el.com>
Subject: Re: [alsa-devel] [PATCH v6 1/3] clk: x86: Add Atom PMC platform clocks

On Fri, Dec 16, 2016 at 7:15 AM, Pierre-Louis Bossart
<pierre-louis.bossart@...ux.intel.com> wrote:
> Hi Stephen,
>
> can you elaborate on the last comment?

Please don't do top posting.

>>> devm_kasprintf()
>>
>> Please no.

That's why I used modal verb "might" instead of "would".

>> It's all local to this function, devm isn't helping anything.
>> Having one kfree() would be good though. And using init.name for
>> the clkdev lookup is probably wrong and should be replaced with
>> something more generic along with an associated device name.
>
> I am not sure I understand this last comment.
> init.name is not a constant, it's made of the "pmc_plt_clk_" string
> concatenated with an id which directly maps to which hardware clock is
> registered. Clients use devm_clk_get() with a "pmc_plt_clk_<n>" argument.

Giving more thoughts about design and use of this I would propose to
do the following.

1. Create under clock framework something like clk-pmc-atom clock
driver (see, for example, clk-fractional-divider, though this one
should indeed go under x86 folder).
2. In real provider, i.e. pmc_atom, create the necessary clock tree
with *names*.

Scheme with ID is fragile, imagine another version of PMC where
ordering would be mixed up? It's not hypothetical since we used to
have this already in pmc_atom for some registers and bits.

-- 
With Best Regards,
Andy Shevchenko