[PATCH v6] PPC440EPx gpio driver
David Brownell
david-b at pacbell.net
Fri Oct 10 11:12:41 EST 2008
On Thursday 09 October 2008, Anton Vorontsov wrote:
>
> > I've incorporated the other changes, with one exception. I want
> > ppc4xx_gpio_get() to return 0 or 1 (rather than Anton's comment that any
> > non-zero value is ok), because when you use the new "export feature" in
> > sysfs, you see the raw value returned from ppc4xx_gpio_get(). So, without
> > the !! in the return statement, you would see a strange value, like 32768
> > instead of 1:
> >
> > # cd gpio208
> > # cat value
> > 32768
> >
> > So, I think it is worth sanitizing the return value here.
>
> I think that nonzero == high assumption is also ok for the userspace.
Actually, I was thinking that userspace might be happier
not having to deal with that ... so that's worth changing
in the sysfs glue. I'd sign off on a patch fixing that.
I seem to recall seeing an explicit policy saying sysfs
exports booleans as 0/1, at some point, though I can't
find it just now.
- Dave
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