Re: [PATCH RESEND v7 2/2] mmc: host: sdhci: Add support to disable SDR104/SDR50/DDR50 based on capability register 0.

Ulf Hansson
2015-06-08T08:38:22Z

On 8 June 2015 at 10:37, Ulf Hansson <ulf.hansson-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org> wrote:
> [...]
>
>>> >
>>> > Can you test this patch on imx SoC ?
>>> >
>>>
>>> (Your email have some format issue.)
>>
>> Yeah missed to sent in plain text mode.
>>
>>>
>>> I have tested this patch and it does not break imx SoC.
>>> You can add my tag.
>>> Tested-by: Dong Aisheng <aisheng.dong-KZfg59tc24xl57MIdRCFDg@public.gmane.org>
>>
>> Thanks Dong !!
>>
>>>
>>> However, it looks to me SDHCI_CAN_VDD_180 is only indicating the host VDD
>>> capabiliies, not IO voltage capability.
>
> I think Dong is correct. I don't think SDHCI_CAN_VDD_180 is not

/s /is not /is

> related to UHS modes at all.
>
> At least the name of the field (SDHCI_CAN_VDD_180) indicates it's
> about VDD/VCC, the core power and not the IO voltage.
>
>> Are you sure on this ?? If SDHCI host VDD is 1.8V then the cards are
>> also capable to operate at 1.8V ? Didn't understand what you mean by
>> IO voltage capability
>>
>>
>>> SD3.0 cards require 1.8v IO voltage support.
>>> So should this bit affect SD3.0 support?
>>
>> The preset value resgister says that SDR modes requires 1.8V and we
>> disable the modes based on capability or quirk.
>
> It requires 1.8V *IO voltage*, not VDD/VCC.
>
> [...]
>
> Kind regards
> Uffe
--
To unsubscribe from this list: send the line "unsubscribe devicetree" in
the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
More majordomo info at http://vger.kernel.org/majordomo-info.html