From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 84E971581E5; Fri, 23 Aug 2024 14:46:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.17 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724424363; cv=none; b=E6OaiZv01F0lPhRauCdGzq+l2aMkAkOYoRyJFiOLLKyy4QUjVGl+mWpRckESLLDM9f1nb/UUFAgqScz0E7gAMHhhk4KXIqHTjQ3TuuzeChJP2LEy9/nt9KWG3uM2oRZ1nTm25OhlLFj2QxZ56oI0GY5KGy7LgvC3ET5OAw5cus0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724424363; c=relaxed/simple; bh=KP7pzsC70WkagQf4cPqKhy6qm2cgrVoiu8S8ZLGfn3w=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=o6lsqe1oWFVRJlvq9dqNVWYq+GoT4jcD1+KoIknaA8zVVqmu5rRkTnUyXaW60uvwG6JKFMiz6D0oMs+1YsAFtERbDA84UDTaOY6rOVAvPM+l7I+/swqDqv3LOpAhhG+ZswrKaEDKV6RMpeOkbhrLGhoFb3KKm71z9Itu7n9DRp8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=none smtp.mailfrom=linux.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=GBADjkRx; arc=none smtp.client-ip=198.175.65.17 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="GBADjkRx" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1724424362; x=1755960362; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=KP7pzsC70WkagQf4cPqKhy6qm2cgrVoiu8S8ZLGfn3w=; b=GBADjkRxkJpsi2d0g1vdspXK2yJYqJkPQmVZDIYqFKuCD/wgG242N5KM jcwQcatPRcXiyO+uELFFvXsxa7gEJgppIMTDel4mGbBi251kJ7/ot1+PN j9+wGgsU8tF6bRB67SFUR3exwyyaFiXj4G/ogtyNRHiz6mM5zNO+758bb RluZpgkUJ6i8mrzuW2PY2Hu5ZEyXLxclMpQsPgf1g74z0rqVj7iF/oogJ pCc2k+2G/4pKR03Pvxg5m8w1Fjg184I1OHnGotijQA+7GFMtz3TEtD/XZ cqCN2fW0vxgRQDzQ0K2mwOafYhYZ4gn3cvFEFybNkdWr34bzSPlXszFqp A==; X-CSE-ConnectionGUID: JWjqakVTT3qjZvuvclygww== X-CSE-MsgGUID: PevFm/GvSfOsrETEnEFVDQ== X-IronPort-AV: E=McAfee;i="6700,10204,11172"; a="23065719" X-IronPort-AV: E=Sophos;i="6.10,170,1719903600"; d="scan'208";a="23065719" Received: from fmviesa005.fm.intel.com ([10.60.135.145]) by orvoesa109.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 23 Aug 2024 07:46:01 -0700 X-CSE-ConnectionGUID: b8WRW3v4R0eSlb7fm7+bEA== X-CSE-MsgGUID: +5wlqm5bTWG6dtp60iGNtA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.10,170,1719903600"; d="scan'208";a="66134472" Received: from smile.fi.intel.com ([10.237.72.54]) by fmviesa005.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 23 Aug 2024 07:45:57 -0700 Received: from andy by smile.fi.intel.com with local (Exim 4.98) (envelope-from ) id 1shVY3-00000000pBz-0Q58; Fri, 23 Aug 2024 17:45:55 +0300 Date: Fri, 23 Aug 2024 17:45:54 +0300 From: Andy Shevchenko To: Ye Zhang Cc: linus.walleij@linaro.org, brgl@bgdev.pl, heiko@sntech.de, linux-gpio@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-rockchip@lists.infradead.org, linux-kernel@vger.kernel.org, mika.westerberg@linux.intel.com, tao.huang@rock-chips.com, finley.xiao@rock-chips.com, tim.chen@rock-chips.com, elaine.zhang@rock-chips.com Subject: Re: [PATCH v2] gpio: rockchip: avoid division by zero Message-ID: References: <20240823034314.62305-1-ye.zhang@rock-chips.com> <20240823034314.62305-2-ye.zhang@rock-chips.com> Precedence: bulk X-Mailing-List: linux-gpio@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240823034314.62305-2-ye.zhang@rock-chips.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo On Fri, Aug 23, 2024 at 11:43:04AM +0800, Ye Zhang wrote: > If the clk_get_rate return '0', it will happen division by zero. At the abstraction level this is good to avoid 0 division and return an error, but... > freq = clk_get_rate(bank->db_clk); > + if (!freq) > + return -EINVAL; ...do you this the absence of debounce here is a fatal error? (Yes, I see it's a fatal when it's bigger than maximum.) > max_debounce = (GENMASK(23, 0) + 1) * 2 * 1000000 / freq; > if (debounce > max_debounce) > return -EINVAL; -- With Best Regards, Andy Shevchenko From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 6BAABC52D7C for ; Fri, 23 Aug 2024 14:47:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=O1pc+iDhJrPfcj27ivWquDzVCmyrKPGnXtq1Aw+bVC8=; b=i5IdNAkozPJvgd 6BVMybEW6nUIIEgwolQz7Q3/gPUJXGrOWo4bWOuHA/0buGt5yomdo6+q68mAE0xM+9wZXQKXEq5Wc zmZtWXW1oU/YGjHEnwQPjp+kExQRxUgTrGZMNyULVqGh3W9fUad4bCeCF5FLocpHh9XJ+ywIwJuS6 iMnfiyhr2N8NaXVhqHwuQ3854f8GOImkaKoiNbdFtvGrTsGnKIhZBTMw8NNjzbwIEbgwhH2Twl1PJ 9I/SZSlgmJSjaXkxi1OnRBx3zXb+z3pHqYJ1alVAz+mNtp3N37AGgLT7ugsiIZREDLK+IW5dpaQh4 0Athi/4axcGtKmEmQvaQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1shVZO-0000000H9uL-3qwq; Fri, 23 Aug 2024 14:47:18 +0000 Received: from mgamail.intel.com ([198.175.65.17]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1shVYB-0000000H9dm-3qDf; Fri, 23 Aug 2024 14:46:05 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1724424364; x=1755960364; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=KP7pzsC70WkagQf4cPqKhy6qm2cgrVoiu8S8ZLGfn3w=; b=F4khDdjybeYt4qECZ6UGYZymivHeUxN/gRjwZ4jDR2VVPTV/iuI2qmpO Qs2NGJjYs0wNZAyhTK4lUUm4OJ7dvtYkR9wZDpMuuwq1QlFXoley68gtk Ovge/tZlFT0D0+YA7zlU1kjYCl0vkeL2cj2uCEhMVxW17iyAm+iy9ChOx m0Kpj4iNe80kY2YSvFtHL7SBCTU6eBkf8fC8X7PWLv5bJj6NAMwCweueA 8JrSvlaySuxAaauUs+a92T/NuAzz3sgekPmJesXqO6F9xTqaDf1yQnloL yF9+BnmJQUxf8seRbQto6qdjBxegFbxiomFp0mLQ36DyfUaa0EHbjTAbS A==; X-CSE-ConnectionGUID: W9RvHWWSTLWQEJG/JVz8fA== X-CSE-MsgGUID: JT9xihD7TdiPm7eY4Q6E3Q== X-IronPort-AV: E=McAfee;i="6700,10204,11172"; a="23065720" X-IronPort-AV: E=Sophos;i="6.10,170,1719903600"; d="scan'208";a="23065720" Received: from fmviesa005.fm.intel.com ([10.60.135.145]) by orvoesa109.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 23 Aug 2024 07:46:01 -0700 X-CSE-ConnectionGUID: b8WRW3v4R0eSlb7fm7+bEA== X-CSE-MsgGUID: +5wlqm5bTWG6dtp60iGNtA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.10,170,1719903600"; d="scan'208";a="66134472" Received: from smile.fi.intel.com ([10.237.72.54]) by fmviesa005.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 23 Aug 2024 07:45:57 -0700 Received: from andy by smile.fi.intel.com with local (Exim 4.98) (envelope-from ) id 1shVY3-00000000pBz-0Q58; Fri, 23 Aug 2024 17:45:55 +0300 Date: Fri, 23 Aug 2024 17:45:54 +0300 From: Andy Shevchenko To: Ye Zhang Cc: linus.walleij@linaro.org, brgl@bgdev.pl, heiko@sntech.de, linux-gpio@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-rockchip@lists.infradead.org, linux-kernel@vger.kernel.org, mika.westerberg@linux.intel.com, tao.huang@rock-chips.com, finley.xiao@rock-chips.com, tim.chen@rock-chips.com, elaine.zhang@rock-chips.com Subject: Re: [PATCH v2] gpio: rockchip: avoid division by zero Message-ID: References: <20240823034314.62305-1-ye.zhang@rock-chips.com> <20240823034314.62305-2-ye.zhang@rock-chips.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20240823034314.62305-2-ye.zhang@rock-chips.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240823_074604_023417_C23AF822 X-CRM114-Status: UNSURE ( 8.94 ) X-CRM114-Notice: Please train this message. X-BeenThere: linux-rockchip@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Upstream kernel work for Rockchip platforms List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "Linux-rockchip" Errors-To: linux-rockchip-bounces+linux-rockchip=archiver.kernel.org@lists.infradead.org On Fri, Aug 23, 2024 at 11:43:04AM +0800, Ye Zhang wrote: > If the clk_get_rate return '0', it will happen division by zero. At the abstraction level this is good to avoid 0 division and return an error, but... > freq = clk_get_rate(bank->db_clk); > + if (!freq) > + return -EINVAL; ...do you this the absence of debounce here is a fatal error? (Yes, I see it's a fatal when it's bigger than maximum.) > max_debounce = (GENMASK(23, 0) + 1) * 2 * 1000000 / freq; > if (debounce > max_debounce) > return -EINVAL; -- With Best Regards, Andy Shevchenko _______________________________________________ Linux-rockchip mailing list Linux-rockchip@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-rockchip