linux-kernel - Re: [PATCH] input: gpio_keys: Don't report events on gpio failure

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Message-ID: <CACRpkdY8KqKa3GpfNo5JQAO5+Z3UG0J99VCg_OjsRTa5MJAaYg@mail.gmail.com>
Date:	Thu, 13 Aug 2015 15:06:56 +0200
From:	Linus Walleij <linus.walleij@...aro.org>
To:	Bjorn Andersson <bjorn.andersson@...ymobile.com>,
	Alexandre Courbot <gnurou@...il.com>
Cc:	Dmitry Torokhov <dmitry.torokhov@...il.com>,
	"linux-input@...r.kernel.org" <linux-input@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	John Stultz <john.stultz@...aro.org>,
	"linux-gpio@...r.kernel.org" <linux-gpio@...r.kernel.org>
Subject: Re: [PATCH] input: gpio_keys: Don't report events on gpio failure

On Tue, Aug 11, 2015 at 12:41 AM, Bjorn Andersson
<bjorn.andersson@...ymobile.com> wrote:

> But then the question first goes to Linus & co.
>
> gpio_chip->get() can return a negative value to indicate errors (and did
> so in this case), all parts of the API seems indicates that we can get
> an error (int vs bool).

Ooops.

> Should we change _gpiod_get_raw_value() to propagate this error?

Yes for now. Can you patch it? :)

>  Or
> should we just ignore this issue and propagate an error as GPIO high
> reading?

I don't know about the future. In some sense GPIOs are so smallish
resources that errorhandling every call to read/write them seem to
be a royal PITA. That is why I wanted to switch them to bool and get
rid of the problem, but now I also see that maybe that was not such a
smart idea, if errors do occur on the set/get_value path.

Alexandre?

Yours,
Linus Walleij
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