[PATCH 01/10] Add a common struct clk

Stephen Boyd
2011-05-02T17:31:28Z

On 05/02/2011 09:55 AM, David Brown wrote:
> On Sun, May 01 2011, Jeremy Kerr wrote:
>
>> Hi Rob,
>>
>>> I think you will find many examples in the kernel where that is not done
>>> by drivers.
>> Drivers should be checking the return value of clk_get - if they don't,
>> it's a bug. This is the logical place to check, rather than before all
>> clock API calls.
>>
>> For cases where there is no clock provided for the device (but is a
>> valid clock on some machines), the platform code should return a no-op
>> clock from the clk_get call. This 'noop clock' would be a good contender
>> for inclusion into the kernel-wide infrastructure, like clk_fixed.
> Having a general fixed clock is a good idea. There seem to be several
> 'dummy' clocks under various subarchs, and Stephen Boyd posted one for
> MSM on March 24.
>
> Most of the MSM drivers check the clk_get and fail to probe the driver
> if the clock is unavailable.

Actually I would like to build the dummy clock into the core and just
have the dummy clock be a NULL pointer. I didn't do this in the MSM code
because clkdev wasn't properly handling the NULL clock case. That has
since been fixed by Russell elsewhere in this thread.

Subject: Re: [PATCH 06/10] clk: Add support for a generic clock multiplexer
Message-ID: <20110418184138.GE25671@n2100.arm.linux.org.uk>
http://lkml.kernel.org/n/20110418184138.GE25671 at n2100.arm.linux.org.uk

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