Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752624AbdCQB7T (ORCPT ); Thu, 16 Mar 2017 21:59:19 -0400 Received: from out1-smtp.messagingengine.com ([66.111.4.25]:59256 "EHLO out1-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751062AbdCQB7O (ORCPT ); Thu, 16 Mar 2017 21:59:14 -0400 X-ME-Sender: X-Sasl-enc: UqiZjMVy8ghsVNpU/KvXmYtNE0EHT1QiEPB1nS+Ha8Bg 1489715634 From: David Rivshin To: linux-gpio@vger.kernel.org, linux-omap@vger.kernel.org, Grygorii Strashko Cc: Santosh Shilimkar , Kevin Hilman , Linus Walleij , Alexandre Courbot , linux-arm@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: [PATCH 1/2] gpio: omap: return error if requested debounce time is not possible Date: Thu, 16 Mar 2017 21:48:55 -0400 Message-Id: <20170317014856.31449-2-drivshin@awxrd.com> X-Mailer: git-send-email 2.9.3 In-Reply-To: <20170317014856.31449-1-drivshin@awxrd.com> References: <20170317014856.31449-1-drivshin@awxrd.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2635 Lines: 83 From: David Rivshin omap_gpio_debounce() does not validate that the requested debounce is within a range it can handle. Instead it lets the register value wrap silently, and always returns success. This can lead to all sorts of unexpected behavior, such as gpio_keys asking for a too-long debounce, but getting a very short debounce in practice. Fix this by returning -EINVAL if the requested value does not fit into the register field. If there is no debounce clock available at all, return -ENOTSUPP. Fixes: e85ec6c3047b ("gpio: omap: fix omap2_set_gpio_debounce") Cc: # 4.3+ Signed-off-by: David Rivshin --- drivers/gpio/gpio-omap.c | 18 ++++++++++++------ 1 file changed, 12 insertions(+), 6 deletions(-) diff --git a/drivers/gpio/gpio-omap.c b/drivers/gpio/gpio-omap.c index efc85a2..c40dbdd 100644 --- a/drivers/gpio/gpio-omap.c +++ b/drivers/gpio/gpio-omap.c @@ -208,9 +208,11 @@ static inline void omap_gpio_dbck_disable(struct gpio_bank *bank) * OMAP's debounce time is in 31us steps * = (GPIO_DEBOUNCINGTIME[7:0].DEBOUNCETIME + 1) x 31 * so we need to convert and round up to the closest unit. + * + * Return: 0 on success, negative error otherwise. */ -static void omap2_set_gpio_debounce(struct gpio_bank *bank, unsigned offset, - unsigned debounce) +static int omap2_set_gpio_debounce(struct gpio_bank *bank, unsigned offset, + unsigned debounce) { void __iomem *reg; u32 val; @@ -218,11 +220,12 @@ static void omap2_set_gpio_debounce(struct gpio_bank *bank, unsigned offset, bool enable = !!debounce; if (!bank->dbck_flag) - return; + return -ENOTSUPP; if (enable) { debounce = DIV_ROUND_UP(debounce, 31) - 1; - debounce &= OMAP4_GPIO_DEBOUNCINGTIME_MASK; + if ((debounce & OMAP4_GPIO_DEBOUNCINGTIME_MASK) != debounce) + return -EINVAL; } l = BIT(offset); @@ -255,6 +258,8 @@ static void omap2_set_gpio_debounce(struct gpio_bank *bank, unsigned offset, bank->context.debounce = debounce; bank->context.debounce_en = val; } + + return 0; } /** @@ -964,14 +969,15 @@ static int omap_gpio_debounce(struct gpio_chip *chip, unsigned offset, { struct gpio_bank *bank; unsigned long flags; + int ret; bank = gpiochip_get_data(chip); raw_spin_lock_irqsave(&bank->lock, flags); - omap2_set_gpio_debounce(bank, offset, debounce); + ret = omap2_set_gpio_debounce(bank, offset, debounce); raw_spin_unlock_irqrestore(&bank->lock, flags); - return 0; + return ret; } static int omap_gpio_set_config(struct gpio_chip *chip, unsigned offset, -- 2.9.3