[i2c] [patch 2.6.23.1, version 4] add support for the PCF8575 chip

[David Brownell]

Why isn't this a "new style" driver?  That would address those
enumeration/discovery issue properly ... by having the boards
just declare which chips exist, on which bus segments.

Also, have a look at

   http://marc.info/?l=linux-arm-kernel&m=119336274312381&w=2

which shows some infrastructure that helps glue such GPIO
expander chips into the generic GPIO framework.  Considering
that I'm used to seeing this type chip used be used to set up
various external circuits or drive LEDs, that seems like a much
more useful way to package pcf857x chips than only having a
kind of strange sysfs interface..

- Dave