[PATCH 01/10] Add a common struct clk

David Brown davidb at codeaurora.org
Mon May 2 12:55:01 EDT 2011


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.

David

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