From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965753AbbLWWgL (ORCPT ); Wed, 23 Dec 2015 17:36:11 -0500 Received: from mail-gw3-out.broadcom.com ([216.31.210.64]:46025 "EHLO mail-gw3-out.broadcom.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934383AbbLWWgA (ORCPT ); Wed, 23 Dec 2015 17:36:00 -0500 X-IronPort-AV: E=Sophos;i="5.20,470,1444719600"; d="scan'208";a="83935451" Subject: Re: [PATCH] pinctrl: nsp-gpio: fix type of iterator To: Andrzej Hajda , Linus Walleij , Scott Branden , Jon Mason References: <1450867041-729-1-git-send-email-a.hajda@samsung.com> <1450867041-729-2-git-send-email-a.hajda@samsung.com> CC: Bartlomiej Zolnierkiewicz , Marek Szyprowski , "open list:PIN CONTROL SUBSYSTEM" , "moderated list:BROADCOM IPROC ARM ARCHITECTURE" , "open list:BROADCOM IPROC ARM ARCHITECTURE" , open list , Yendapally Reddy Dhananjaya Reddy From: Ray Jui Message-ID: <567B21CD.9090900@broadcom.com> Date: Wed, 23 Dec 2015 14:35:57 -0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.4.0 MIME-Version: 1.0 In-Reply-To: <1450867041-729-2-git-send-email-a.hajda@samsung.com> Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org + Reddy On 12/23/2015 2:37 AM, Andrzej Hajda wrote: > Iterator i declared as unsigned is always non-negative so the > loop will never end. > > The problem has been detected using proposed semantic patch > scripts/coccinelle/tests/unsigned_lesser_than_zero.cocci [1]. > > [1]: http://permalink.gmane.org/gmane.linux.kernel/2038576 > > Signed-off-by: Andrzej Hajda > --- > drivers/pinctrl/bcm/pinctrl-nsp-gpio.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/pinctrl/bcm/pinctrl-nsp-gpio.c b/drivers/pinctrl/bcm/pinctrl-nsp-gpio.c > index 34648f6..ad5b04c 100644 > --- a/drivers/pinctrl/bcm/pinctrl-nsp-gpio.c > +++ b/drivers/pinctrl/bcm/pinctrl-nsp-gpio.c > @@ -439,7 +439,8 @@ static int nsp_gpio_set_strength(struct nsp_gpio *chip, unsigned gpio, > static int nsp_gpio_get_strength(struct nsp_gpio *chip, unsigned gpio, > u16 *strength) > { > - unsigned int i, offset, shift; > + unsigned int offset, shift; > + int i; > u32 val; > unsigned long flags; > > The fix is a valid fix. And at the same time it exposes other potential issues in the driver. I just found the loop used in _set_strength and _get_strength is inconsistent: In _set_strength: 427 for (i = GPIO_DRV_STRENGTH_BITS; i > 0; i--) { For i to start at GPIO_DRV_STRENGTH_BITS, it seems to be wrong. 428 val = readl(chip->io_ctrl + offset); 429 val &= ~BIT(shift); 430 val |= ((strength >> (i-1)) & 0x1) << shift; 431 writel(val, chip->io_ctrl + offset); 432 offset += 4; 433 } In _get_strength: 451 for (i = (GPIO_DRV_STRENGTH_BITS - 1); i >= 0; i--) { 452 val = readl(chip->io_ctrl + offset) & BIT(shift); 453 val >>= shift; 454 *strength += (val << i); 455 offset += 4; 456 } Reddy, could you please review and comment? Thanks, Ray