From mboxrd@z Thu Jan 1 00:00:00 1970 From: Geert Uytterhoeven Subject: Re: [PATCH] gpio: fix deferred probe detection for legacy API Date: Tue, 2 Dec 2014 15:11:13 +0100 Message-ID: References: <1417527724-24960-1-git-send-email-acourbot@nvidia.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Return-path: In-Reply-To: <1417527724-24960-1-git-send-email-acourbot@nvidia.com> Sender: linux-kernel-owner@vger.kernel.org To: Alexandre Courbot Cc: Linus Walleij , "linux-gpio@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Alexandre Courbot , Linux-sh list List-Id: linux-gpio@vger.kernel.org Hi Alexandre, On Tue, Dec 2, 2014 at 2:42 PM, Alexandre Courbot 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 > Signed-off-by: Alexandre Courbot Thanks, this restored functionality. There's still a loud WARN(1, "invalid GPIO %d\n", gpio) in gpio_to_desc(). Tested-by: Geert Uytterhoeven Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds