Hi Dong,

On Fri, Jun 12, 2015 at 12:22 AM, Dong Aisheng <b29...@freescale.com> wrote:

> I think this patch will break the eMMC DDR 3.3v mode support.

I don't think so.

This patch only changes the behaviour when 'no-1-8-v' property is used.

This custom board has an eMMC that can operate at 1.8V, but the board
itself can only provide 3.3V.

In this case we need to pass 'no-1-8-v' as explained in
Documentation/devicetree/bindings/mmc/mmc.txt:

"- no-1-8-v: when present, denotes that 1.8v card voltage is not supported on
  this system, even if the controller claims it is."

Then in this case we should not set MMC_CAP_1_8V_DDR, which will make
the card to work at 3.3V.

Regards,

Fabio Estevam
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