linux-kernel - Re: [PATCH] gpio: fix deferred probe detection for legacy API

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Date:	Tue, 2 Dec 2014 23:22:05 +0900
From:	Alexandre Courbot <gnurou@...il.com>
To:	Linus Walleij <linus.walleij@...aro.org>
Cc:	Alexandre Courbot <acourbot@...dia.com>,
	Geert Uytterhoeven <geert@...ux-m68k.org>,
	"linux-gpio@...r.kernel.org" <linux-gpio@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] gpio: fix deferred probe detection for legacy API

On Tue, Dec 2, 2014 at 11:20 PM, Alexandre Courbot <gnurou@...il.com> wrote:
> On Tue, Dec 2, 2014 at 11:19 PM, Linus Walleij <linus.walleij@...aro.org> wrote:
>> On Tue, Dec 2, 2014 at 2:42 PM, Alexandre Courbot <acourbot@...dia.com> wrote:
>>
>>> Commit 14e85c0e69d5 ("gpio: remove gpio_descs global array") changed
>>> gpio_to_desc()'s behavior to return NULL not only for GPIOs numbers
>>> not in the valid range, but also for all GPIOs whose controller has not
>>> been probed yet. Although this behavior is more correct (nothing hints
>>> that these GPIO numbers will be populated later), this affects
>>> gpio_request() and gpio_request_one() which call gpiod_request() with a
>>> NULL descriptor, causing it to return -EINVAL instead of the expected
>>> -EPROBE_DEFER for a non-probed GPIO.
>>>
>>> gpiod_request() is only called with a descriptor obtained from
>>> gpio_to_desc() from these two functions, so address the issue there.
>>>
>>> Other ways to obtain GPIOs rely on well-defined mappings and can thus
>>> return -EPROBE_DEFER only for relevant GPIOs, and are thus not affected
>>> by this issue.
>>>
>>> Reported-by: Geert Uytterhoeven <geert@...ux-m68k.org>
>>> Signed-off-by: Alexandre Courbot <acourbot@...dia.com>
>>
>> Patch applied with Geert's tested tag.
>
> I just send a v2 which only prints the warning if the GPIO is outside
> of the valid range (better for legacy API).

... although contrary to what the log says I forgot to add Geerts
Tested-by tag. Sorry for the noise.

Alex (Zzzz... -_- )
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