[U-Boot] [RFC PATCH 1/3] sandbox: gpio: WIP add basic driver for simulating GPIOs

[Simon Glass]

Hi Mike,

On Fri, Oct 28, 2011 at 5:42 PM, Mike Frysinger <vapier at gentoo.org> wrote:
> ignoring the upgrade issues, i think this is useful.  only thing
> "missing" is having the pin update state externally, but maybe i'm
> crazy in thinking we need that.  it certainly could be done in a
> follow up patch once your v2 of this patch gets updated, and once we
> actually have a proposed interface that someone was able to make work
> (vs us dreaming up something crazy like sockets/files/pipes/etc...).
> -mike
>

Yes. It depends on your definition of 'externally'. I am mostly
interested in self-contained tests, where we compile U-Boot against
its test code and run it very fast. However there is enormous scope
for going beyond that as has been discussed before - things like
making U-Boot talk on the host's Ethernet/ serial / USB ports, etc.

The tricky thing to get right here is the placement of the state. I
think we want to avoid test state in drivers where possible - on the
other hand we need drivers to be able to pretend to be broken, etc. If
we provide some sort of generic input/output config/log files for test
state, then I suppose converting to sockets/pipes is not a big step.
This is wrapped up in what the test harness looks like also. Are we
getting ahead of ourselves yet? ;-)

Regards,
Simon