Re: [Patch v5 2/2] gpio: Document GPIO hogging mechanism

From: Benoit Parrot
Date: Mon Jan 12 2015 - 11:42:53 EST


Linus Walleij <linus.walleij@xxxxxxxxxx> wrote on Mon [2015-Jan-12 11:20:14 +0100]:
> On Fri, Dec 19, 2014 at 9:07 PM, Benoit Parrot <bparrot@xxxxxx> wrote:
>
> > Add GPIO hogging documentation to gpio.txt
> >
> > Signed-off-by: Benoit Parrot <bparrot@xxxxxx>
> > Reviewed-by: Alexandre Courbot <acourbot@xxxxxxxxxx>
>
> This is starting to look good ...
>
> > + line_b {
> > + gpio-hog;
> > + gpios = <6 0>;
> > + state = "output-low";
>
> I don't like the state string.
>
> Instead have boolean properties for all states.
>
> line_b {
> gpio-hog;
> gpios = <6 0>;
> output-low;
> line-name = "foo-bar-gpio";
> }
>
> Then use of_property_read_bool() in the code to check which
> state is to be selected intially. You can check that no mutually
> exclusive state are selected, I don't like that an arbitrary string
> select the state like that, if we do it that way an enumerator would
> be better, I prefer bools.

I am sorry but that is how it was originally in the first patch.
Alexandre's review comment suggested this method in [1] and [2] (below).

Alexandre, any comments?

[1] http://marc.info/?l=linux-gpio&m=141456662426151&w=2

[2] http://marc.info/?l=linux-gpio&m=141715982424744&w=2

>
> Yours,
> Linus Walleij
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