Re: [PATCH 3/4] gpio: dt-bindings: Declare gpio-hog optional for GPIO subnodes

[Rob Herring <robh@xxxxxxxxxx>]

On Tue, Mar 8, 2016 at 9:53 PM, Linus Walleij <linus.walleij@xxxxxxxxxx> wrote:
> On Wed, Feb 24, 2016 at 6:25 AM, Rob Herring <robh@xxxxxxxxxx> wrote:
>> On Tue, Feb 23, 2016 at 08:54:48AM +0100, Markus Pargmann wrote:
>
>>> +Optional properties:
>>> +- line-name:  The GPIO name. If not present the node name is used.
>>
>> I'd like to deprecate line-name in favor of the standard property
>> for user visible names "label".
>
> This causes some unfortunate confusion wrt internal linux naming.

Yes.

> GPIO lines have two "names"
>
> - The "name" is what the line (pin) is named
>   on the chip, or the name of the rail going out on the board, from the chip,
>   so it is a producer name.

Who/what uses this?

> - Then the GPIO consumers set a second name, called "label"
>   (confusingly) so we can see in e.g. debugfs and now also the userspace
>   ABI who is using it.
>
> I named these "name" and "consumer" in the userspace ABI, I think
> I should take a round and rename it from "label" to "consumer"
> also inside the kernel to avoid confusion with this, because "label"
> in DT is going to be converted to "name" in the GPIOlib and
> then it also has something named "label" and that is another thing,
> argh!

There is still confusion because DT label should be the consumer side,
not the SoC pin name.

Then of course you could have 3 levels of names needed if you have SoC
pin, board connector pin, and mezzanine consumer.

Rob
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