Re: [PATCH] mmc: MMC 4.4 DDR support

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Adrian,

Let me rephrase my question.  

I don't see why both CAPS are needed and why the voltage is specified in the CAPS.  If my understanding is correct the voltage range supported by the host controller is known in the MMC layer.  If the voltage range is supported  and the MMC chip capability says it supports DDR in that range that should be enough for the mmc layer to decide to use DDR.  The host controller should only set the one CAPS option that say the controller supports DDR.
 
On Oct 8, 2010, at 12:02 AM, Adrian Hunter wrote:

> On 01/10/10 06:01, ext Philip Rakity wrote:
>> 
>> I was wondering if we could remove one of the CAPS for DDR voltage (MMC_CAP_1_8V_DDR and MMC_CAP_1_2V_DDR). Both 1.2 and 1.8v are defined in the JEDEC Standard No. 84-A441.
>> 
>> The sd 3.0 host controller only defines the option for 1.8v.  I cannot see a way to set 1.2v.
>> 
>> If this makes sense I can prepare a patch.--
> 
> If the host controller does not support 1.2V DDR then it should definitely
> not set MMC_CAP_1_2V_DDR.  That is precisely what the caps are for.
> 
> 
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