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

From: Arend van Spriel
Date: Mon Jan 12 2015 - 05:28:11 EST


On 01/12/15 11:20, Linus Walleij wrote:
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.

To avoid the mutual exclusive state checking, would it not be more straightforward to use numeric enum values defined in boot/dts/include.

Regards,
Arend

Yours,
Linus Walleij
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