linux-kernel - Re: [alsa-devel] [RFC PATCH] mfd: arizona: Add gating of external MCLKn clocks

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Date:   Thu, 25 Aug 2016 12:18:47 +0200
From:   Sylwester Nawrocki <s.nawrocki@...sung.com>
To:     Charles Keepax <ckeepax@...nsource.wolfsonmicro.com>
Cc:     broonie@...nel.org, alsa-devel@...a-project.org,
        lee.jones@...aro.org, linux-kernel@...r.kernel.org
Subject: Re: [alsa-devel] [RFC PATCH] mfd: arizona: Add gating of external
 MCLKn clocks

On 08/23/2016 06:28 PM, Charles Keepax wrote:
> Apologies it seems I missed another version of this on the
> mailing list, please do feel free to add me or the
> patches@...nsource.wolfsonmicro.com list as a direct CC on
> any patches using our CODECs, I am always more than happy to look
> over things and feel bad when I miss stuff. I will have a look
> at the latest version of the patch.

Actually I should have copied you on the last iteration after
addressing your review comments, sorry about this omission.

> I think we should be able to do something requesting the 32k
> approximately as your existing patch here does, but then
> requesting the main MCLK from the set_pll and set_sysclk
> handlers. Eventually I would like the internal SYSCLK and FLLs
> represented in the clock framework, so I want to have a quick
> think about how that would migrate over. Let me see what I can
> come up with here.

Sounds good, I assume you mean enabling/disabling from the set_pll
and set_syclk handlers. Do you find any issues with that? I think
the CODEC should ensure external MCLK is enabled when setting FLL,
otherwise it will not lock?
Presumably arizona_set_fll() and arizona_set_sysclk() are places
where it should be checked what the root source clock is and enable
it if it's not yet enabled?