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Message-ID: <9e4733910810300939x40a7afear7a49557604ced628@mail.gmail.com>
Date: Thu, 30 Oct 2008 12:39:42 -0400
From: "Jon Smirl" <jonsmirl@gmail.com>
To: "Jonas Bonn" <jonas.bonn@gmail.com>
Subject: Re: [RFC] API for system clocks (oscillators)
Cc: linux-kernel@vger.kernel.org
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On Thu, Oct 30, 2008 at 12:27 PM, Jonas Bonn <jonas.bonn@gmail.com> wrote:
>>
>> How does this compare to the framework in linux/include/linux/clk.h?
>>
>
> clk.h is pretty much just an infrastructure for "storing" clock data
> and accessors... it does not provide:
>
> i) Constraints on selectable frequencies of active devices
> ii) Notifiers on frequency change, including changes due to events
> such as reparenting
>
> These are the big ones that cause headaches.  When I want to switch
> frequency, I have to check elsewhere which devices are active and
> which frequencies they allow.  When a frequency changes, I have to
> manually make sure that the active devices are notified properly of
> the change.  These are the main things that my document tries to
> consolidate into one framework.  Like I said, I'm not sure it's the
> right approach, that's why I requested feedback...

You could probably work those features into the existing clk framework.
clk_set_rate() could compute the constrains and return an error.
The API could be expanded with notifier support.

-- 
Jon Smirl
jonsmirl@gmail.com
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