Re: [PATCH] gpio: consumer: Remove WARN_ON(1) when GPIOLIB is disabled

[Linus Walleij <linus.walleij@xxxxxxxxxx>]

On Fri, Jul 28, 2017 at 6:21 PM, Fabio Estevam <fabio.estevam@xxxxxxx> wrote:

> gpiod_get_optional() returns NULL when GPIOLIB is disabled since
> commit 22c403676dbbb7c6 ("gpio: return NULL from gpiod_get_optional when
> GPIOLIB is disabled").
>
> However, many gpiod functions still have WARN_ON(1) in their
> GPIOLIB=n stubs, which causes warnings in drivers even if the
> GPIO descriptor is requested via gpiod_get_optional().
>
> Prior to commit 22c403676dbbb7c6 ("gpio: return NULL from
> gpiod_get_optional when GPIOLIB is disabled") it was indeed true
> the comment: "GPIO can never have been requested" as gpiod_get_optional()
> used to return an error.
>
> After this commit the returned value is NULL, so the comment and
> WARN_ON(1) are no longer accurate.
>
> An example of this kernel warning can be see in this report:
> https://www.spinics.net/lists/kernel/msg2563045.html
>
> Remove the WARN_ON(1) so that drivers can silently work fine
> without kernel warnings when GPIOLIB is disabled.
>
> Reported-by: Sergei Shtylyov <sergei.shtylyov@xxxxxxxxxxxxxxxxxx>
> Signed-off-by: Fabio Estevam <fabio.estevam@xxxxxxx>

I explained in another commend why I see this as a non-issue.

Drivers that call GPIO accessors likely need them to work properly.

If they see these messages I suspect it is because of missing
depends on or select of GPIOLIB in their Kconfig.

Yours,
Linus Walleij
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