Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753686AbbLXFd6 (ORCPT ); Thu, 24 Dec 2015 00:33:58 -0500 Received: from mail-gw1-out.broadcom.com ([216.31.210.62]:22974 "EHLO mail-gw1-out.broadcom.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753566AbbLXFd4 (ORCPT ); Thu, 24 Dec 2015 00:33:56 -0500 X-IronPort-AV: E=Sophos;i="5.20,472,1444719600"; d="scan'208";a="84210761" Subject: Re: [PATCH] pinctrl: nsp-gpio: fix type of iterator To: Ray Jui , 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> <567B21CD.9090900@broadcom.com> CC: Bartlomiej Zolnierkiewicz , Marek Szyprowski , "open list:PIN CONTROL SUBSYSTEM" , "moderated list:BROADCOM IPROC ARM ARCHITECTURE" , bcm-kernel-feedback-list , open list From: Yendapally Reddy Dhananjaya Reddy Message-ID: <567B83BE.5090800@broadcom.com> Date: Thu, 24 Dec 2015 11:03:50 +0530 User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:38.0) Gecko/20100101 Thunderbird/38.4.0 MIME-Version: 1.0 In-Reply-To: <567B21CD.9090900@broadcom.com> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2587 Lines: 80 On 12/24/2015 4:05 AM, Ray Jui wrote: > + 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? Hi Ray, The logic is correct. The drive strength has three bits distributed in three registers. In one case the "-1" is in for loop initialization and the other case it is in the for loop body. The fix looks good. Thanks Dhananjay > Thanks, > > Ray > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/