Hi Grant,

quoted

+      - compatible : should be "linux,mmc-spi".
+      - linux,modalias  - should be "of_mmc_spi".

I'm not even sure if the whole linux,modalias is even a good idea.  I
had kind of thrown it in there as a convenient way to override
compatible when needed, but I haven't really thought it out very well
and I think it is rather a hack.

The real problem is we don't yet have good method (or place) to apply
a translation table from compatible values to modaliases.  Ideally,
the translations should be part of the drivers themselves, but that
causes a chicken and egg problem of needing to load the driver to get
access to the table to know if it is the correct driver... Of course,
I'm really not very familiar with the whole module autoloading
mechanism.  Regardless; binding should be based on compatible, not on
a hacky and bogus linux,modalias property.

i2c exactly has the same problem. Here the compatible entry is used
in drivers/of/of_i2c.c and mangled into a name to be used as modalias.
It's still sort of hackish, but it seems to be a compromise acceptable
by both OF and i2c folks.

Thanks,
Jochen