From patchwork Tue Dec 2 14:15:05 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexandre Courbot X-Patchwork-Id: 416882 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 150C6140082 for ; Wed, 3 Dec 2014 01:20:38 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751535AbaLBOUh (ORCPT ); Tue, 2 Dec 2014 09:20:37 -0500 Received: from gnurou.org ([207.192.72.5]:41410 "EHLO mail.gnurou.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751222AbaLBOUh (ORCPT ); Tue, 2 Dec 2014 09:20:37 -0500 Received: from aramis.localdomain (softbank126010191003.bbtec.net [126.10.191.3]) by mail.gnurou.org (Postfix) with ESMTPSA id 5BC652FB86; Tue, 2 Dec 2014 23:22:07 +0900 (JST) From: Alexandre Courbot To: Linus Walleij , Geert Uytterhoeven Cc: linux-gpio@vger.kernel.org, linux-kernel@vger.kernel.org, gnurou@gmail.com, Alexandre Courbot Subject: [PATCH v2] gpio: fix deferred probe detection for legacy API Date: Tue, 2 Dec 2014 23:15:05 +0900 Message-Id: <1417529705-1515-1-git-send-email-acourbot@nvidia.com> X-Mailer: git-send-email 2.1.3 In-Reply-To: <1417527724-24960-1-git-send-email-acourbot@nvidia.com> References: <1417527724-24960-1-git-send-email-acourbot@nvidia.com> Sender: linux-gpio-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-gpio@vger.kernel.org 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 --- v2: - Add Geert's Tested-by - Only display scary warning on gpio_to_desc() is the GPIO is outside the valid range (pre gpio_desc array removal behavior) drivers/gpio/gpiolib-legacy.c | 12 +++++++++++- drivers/gpio/gpiolib.c | 4 +++- 2 files changed, 14 insertions(+), 2 deletions(-) diff --git a/drivers/gpio/gpiolib-legacy.c b/drivers/gpio/gpiolib-legacy.c index 078ae6c..8b83099 100644 --- a/drivers/gpio/gpiolib-legacy.c +++ b/drivers/gpio/gpiolib-legacy.c @@ -24,6 +24,10 @@ int gpio_request_one(unsigned gpio, unsigned long flags, const char *label) desc = gpio_to_desc(gpio); + /* Compatibility: assume unavailable "valid" GPIOs will appear later */ + if (!desc && gpio_is_valid(gpio)) + return -EPROBE_DEFER; + err = gpiod_request(desc, label); if (err) return err; @@ -62,7 +66,13 @@ EXPORT_SYMBOL_GPL(gpio_request_one); int gpio_request(unsigned gpio, const char *label) { - return gpiod_request(gpio_to_desc(gpio), label); + struct gpio_desc *desc = gpio_to_desc(gpio); + + /* Compatibility: assume unavailable "valid" GPIOs will appear later */ + if (!desc && gpio_is_valid(gpio)) + return -EPROBE_DEFER; + + return gpiod_request(desc, label); } EXPORT_SYMBOL_GPL(gpio_request); diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index 0b271ef8..56b7c5d 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -77,7 +77,9 @@ struct gpio_desc *gpio_to_desc(unsigned gpio) spin_unlock_irqrestore(&gpio_lock, flags); - WARN(1, "invalid GPIO %d\n", gpio); + if (!gpio_is_valid(gpio)) + WARN(1, "invalid GPIO %d\n", gpio); + return NULL; } EXPORT_SYMBOL_GPL(gpio_to_desc);