Re: [PATCH] gpio: mention in DT binding doc that <name>-gpio is also supported

[Javier Martinez Canillas]

Hello Alexandre,

On 09/18/2015 05:44 PM, Alexandre Courbot wrote:
> On Thu, Sep 17, 2015 at 10:33 AM, Javier Martinez Canillas
> <javier@xxxxxxxxxxxxxxx> wrote:
>> The GPIO DT binding doc mentions that GPIO are mapped by defining
>> a <name>-gpios property in the consumer device's node but a -gpio
>> sufix is also supported after commit:
>>
>> dd34c37aa3e8 ("gpio: of: Allow -gpio suffix for property names")
>>
>> Update the DT binding documentation to match the implementation.
>>
>> Signed-off-by: Javier Martinez Canillas <javier@xxxxxxxxxxxxxxx>
>>
>> ---
>> Hello,
>>
>> The GPIO documentation was updated to mention that the -gpio sufix
>> is also supported in patch https://lkml.org/lkml/2015/9/1/117 that
>> already landed in Torvalds tree.
>>
>> I now noticed that the DT binding also only mentions -gpios so I'm
>> posting this patch that adds -gpio to the DT binding documentation.
> 
> I think I remember that -gpio is considered obsolete and its use
> should thus not be encouraged, which is the reason why the
> documentation does not mention it. We could mention it and add a note
> saying that it should not be used for new bindings, but all in all
> isn't it better to keep the documentation clear of such use cases that
> will not be accepted for new patches anyway?
>

I agree that if that's the case then it should be documented. Currently
by reading the docs there is no way to tell if -gpio was only added to
support old DT bindings and should not be used or if is that the docs
were not updated when <function>-gpio parsing was added to gpiolib.

I can re-spin the patch making it clear that even when the -gpio suffix
is supported, it's only there for compatibility reasons and should not
be used for newer bindings.

And also Documentation/gpio/board.txt has to be updated now since now it
mentions <function>-gpio but does not say that should not be used.

Best regards,
-- 
Javier Martinez Canillas
Open Source Group
Samsung Research America
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