Re: [PATCH] mmc: agressive clocking framework v9

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On Nov 6, 2010, at 6:44 PM, Nicolas Pitre wrote:

> On Sat, 6 Nov 2010, Philip Rakity wrote:
> 
>> 
>> We need a way to specify
>> 
>> a) Hardware can support clock gating setting the clock to 0 in the 
>> call to set_ios (with hardware clock gating enabled) becomes a no-op 
>> so some care is needed which is why I suggested another field in the 
>> ios structure.
> 
> Why should the core code care?
> 
> What difference is there with the core telling the controller driver to 
> set the clock to a frequency of 0 ?
> 
> 
> Nicolas


When h/w clock gating is enabled then sd clocks are disabled/enabled by the sd controller; there is nothing for the core/ layer to do.

I am concerned that having the core/ layer ask for clocks off and on is

a) not needed when h/w clock gating is enabled
b) may invoke bad behavior in the controller
c) is not optimal since the h/w is already handling this. --
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