Re: [PATCH RFC 2/3] mmc: core: add new cap for 3.3V only DDR MMCs

Hi Shawn,

Shawn Lin [off-list ref] hat am 7. August 2016 um 04:07
geschrieben:


在 2016/8/6 22:18, Stefan Wahren 写道:

quoted

Hi Marek,

quoted

Marek Vasut [off-list ref] hat am 6. August 2016 um 15:14 geschrieben:


On 08/06/2016 02:55 PM, Stefan Wahren wrote:

quoted

This patch based on the work of Fabio Estevam:
"[PATCH v2] mmc: core: Do not set mmc voltage to 1.8V when
'no-1-8-v' is present"

It adds the support for 3.3V only DDR MMC hosts.

Do such cards even exist ? Do you have a link where I can find some ?

i never said anything about SD cards. I mean eMMC modules which usually have
8
data pins like this one [1].

Please don't blame me if it's not compatible to i.MX28. It's only an
example.

[1] -
http://datasheet.octopart.com/THGBM3G4D1FBAIGH2H-Toshiba-datasheet-20748880.pdf

I download the datasheet you mentioned, and I explicitly see it
describe 1V8 everywhere, especially for the section of "ELECTRICAL
CHARACTERISTICS".

I never see one eMMC claiming DDR52 capability but doesn't support 1V8
so far. Could you kindly share me the part number of the eMMC you are
using? :)

sorry the subject line is misleading. The capability flag is about the host not
about the MMC itself. There are hosts which doesn't support 1.8V. I will clarify
this in the next version.
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