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

Ulf Hansson
2015-06-08T08:37:10Z

[...]

>> >
>> > 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@freescale.com>
>
> 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
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