Re: [PATCH] gpio sysfs: add a "toggle" value

[Mike Frysinger <vapier.adi@gmail.com>]

On Thu, Jun 4, 2009 at 05:15, David Brownell wrote:
> On Thursday 04 June 2009, Mike Frysinger wrote:
>> the point was to lower the number of user<->kernel transitions.  yes,
>> all of this stuff can of course be done in the shell, but it's hard to
>> push limits when the interface is tying your hands and sitting on your
>> back.
>
> So what's the application that needs to do all this in
> userspace yet which can't hook up a quick kernel driver?
>
> I don't like the idea of embedding any kind of interpreter
> in the sysfs interface, but that's the direction you seem
> to be heading ...

i dont view the userspace GPIO interface as a simple "i want to wiggle
pins for fun and testing".  i see it as a dynamic method for building
userspace drivers for simple devices.  as such, having a very simple
"command language" for optimizing the interaction provides a pretty
good trade off between kernel complexity and lowering overhead imo.
-mike