[PATCH] sdhci: Add support for hosts that are only capable of 1-bit transfers

[Pierre Ossman]

On Fri, 12 Jun 2009 00:15:45 +0400
Anton Vorontsov <avorontsov at ru.mvista.com> wrote:

> Some hosts (hardware configurations, or particular SD/MMC slots) may
> not support 4-bit bus. For example, on MPC8569E-MDS boards we can
> switch between serial (1-bit only) and nibble (4-bit) modes, thought
> we have to disable more peripherals to work in 4-bit mode.
> 
> Along with some small core changes, this patch modifies sdhci-of
> driver, so that now it looks for "mode" property in the device-tree.
> 
> Signed-off-by: Anton Vorontsov <avorontsov at ru.mvista.com>
> ---
> 
> Pierre, I'm not sure if a quirk would be appropriate here. If so,
> I can redo the patch with FORCE_1_BIT_DATA quirk.
> 

I'd prefer a quirk, yes. 4-bit support is mandated so this would be a
deviation from the spec and such should always be handled by quirks for
clarity.

(I do think it is silly that they made it mandatory though considering
the embedded market)

Rgds
-- 
     -- Pierre Ossman

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