OK, but maybe we could keep the part about the mmcard for the eMMC to
emphasize that we need to setup this option for the controller.

Right!

quoted

quoted

+
+- no-1-8-v:
+  Select this property when 1.8V signaling voltage supply is unavailable.
+  When this property is enabled, both mmc-ddr-1_8v and mmc-hs400-1_8v should be
+  cleared.

Please don't use this sdhci property, unless really needed.

Actually this is a mmc property, at least it is described in this the
mmc binding:
Documentation/devicetree/bindings/mmc/mmc.txt

Yes, the documentation is wrong. It should we be moved into the docs for sdhci.

I will send a patch updating it. Apologize for the misleading information.

The description of this optional property is:
"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."

So as it is also part of the mmc binding we can remove it from our
bindings as we are going to do it for the other mmc property.

Nope.

But I am curious to know why do you think we could use it without any
need. Are you aware of some abuse of this property?

Yes.

quoted

Perhaps you can elaborate exactly why it makes sense for your case. Or
perhaps we already discussed this, in either case, please re-fresh my
mind.

For instance we need it now on the 7040DB board which does not have the
1.8V signal voltage available.

It it's better to describe what the controller/board support, instead
of what it doesn't.

I think you should be able to use other existing mmc DT bindings
(perhaps also you need the brand new "mmc-ddr-3_3v"), instead of the
"no-1-8-v".

Kind regards
Uffe