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

Suman Tripathi
2015-06-10T18:24:40Z

Hi Ulf, Dong

On Mon, Jun 8, 2015 at 2:08 PM, Ulf Hansson <ulf.hansson@linaro.org> wrote:
> On 8 June 2015 at 10:37, Ulf Hansson <ulf.hansson@linaro.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@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
>
> /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.

I agree on this now . I will post a version where this quirk will be
added for arasan 4.9a that doesn't support 1.8v voltage signalling.

>>
>> [...]
>>
>> Kind regards
>> Uffe

--
Thanks,
with regards,
Suman Tripathi