Re: [PATCH 4/5] gpiolib: handle deferral probe error

From: Grant Likely
Date: Fri Oct 07 2011 - 18:10:02 EST

On Fri, Oct 7, 2011 at 4:06 AM, Alan Cox <alan@xxxxxxxxxxxxxxxxxxx> wrote:
> On Fri, 07 Oct 2011 10:33:09 +0500
> "G, Manjunath Kondaiah" <manjugk@xxxxxx> wrote:
>> The gpio library should return -EPROBE_DEFER in gpio_request
>> if gpio driver is not ready.
> Why not use the perfectly good existing error codes we have for this ?
> We have EAGAIN and EUNATCH both of which look sensible.

I want a distinct error code for probe deferral so that a) it doesn't
overlap with something a driver is already doing, and b) so that all
the users can be found again at a later date.

That said, I'm not in agreement with this patch. It is fine for gpio
lib to have a code that means the pin doesn't exist (yet), but the
device driver needs to be the one to decide whether or not it is
appropriate to use probe deferral.

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