Re: [PATCH] gpiolib: return -ENOENT when no GPIO mapping exists

[Linus Walleij]

On Fri, Dec 6, 2013 at 3:06 AM, Alexandre Courbot <acourbot@xxxxxxxxxx> wrote:

> Some devices drivers make use of optional GPIO parameters. For such
> drivers, it is important to discriminate between the case where no
> GPIO mapping has been defined for the function they are requesting, and
> the case where a mapping exists but an error occured while resolving it
> or when acquiring the GPIO.
>
> This patch changes the family of gpiod_get() functions such that they
> will return -ENOENT if and only if no GPIO mapping is defined for the
> requested function. Other error codes are used when an actual error
> occured during the GPIO resolution.
>
> Signed-off-by: Alexandre Courbot <acourbot@xxxxxxxxxx>
> ---
> I think this change should be merged early as not having it may prevent
> some users to switch to gpiod. I stumbled upon this issue while
> considering porting a simple driver (pwm_bl) that has an optional GPIO
> parameter.
>
> Mika, Andy: if Linus agrees with this change, could you take care of
> having -ENOENT returned as well for the ACPI and SFI GPIOs lookup?
> My understanding of ACPI was not sufficient to allow me to do it myself.
> SFI OTOH should be trivial as it is a simple table.

I'm aligned with this change, just waiting for a v2 with the fix
requested by Andy to appear (maybe it's further up in the mail log
I don't know...)

Yours,
Linus Walleij
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