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[209.132.180.67]) by mx.google.com with ESMTP id s7-v6si27357534pgj.480.2018.09.21.10.48.06; Fri, 21 Sep 2018 10:48:22 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=intel.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2391065AbeIUXgl (ORCPT + 99 others); Fri, 21 Sep 2018 19:36:41 -0400 Received: from mga14.intel.com ([192.55.52.115]:11742 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390365AbeIUXgl (ORCPT ); Fri, 21 Sep 2018 19:36:41 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga007.fm.intel.com ([10.253.24.52]) by fmsmga103.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 21 Sep 2018 10:46:44 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.54,285,1534834800"; d="scan'208";a="71889326" Received: from yoojae-mobl1.amr.corp.intel.com (HELO [10.7.153.151]) ([10.7.153.151]) by fmsmga007.fm.intel.com with ESMTP; 21 Sep 2018 10:46:35 -0700 Subject: Re: [PATCH] i2c: aspeed: fixed invalid clock parameters for very large divisors To: Brendan Higgins , benh@kernel.crashing.org, joel@jms.id.au, andrew@aj.id.au Cc: linux-i2c@vger.kernel.org, openbmc@lists.ozlabs.org, linux-aspeed@lists.ozlabs.org, linux-kernel@vger.kernel.org References: <20180920232820.243734-1-brendanhiggins@google.com> From: Jae Hyun Yoo Message-ID: <07af0253-1efc-2ae1-93fb-ebcc1996d768@linux.intel.com> Date: Fri, 21 Sep 2018 10:46:34 -0700 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <20180920232820.243734-1-brendanhiggins@google.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Brendan, nit: Title in imperative mood. I'd put 'fix' instead of 'fixed'. On 9/20/2018 4:28 PM, Brendan Higgins wrote: > The function that computes clock parameters from divisors did not > respect the maximum size of the bitfields that the parameters were > written to. This fixes the bug. > > This bug can be reproduced with (and this fix verified with) the test > at: https://kunit-review.googlesource.com/c/linux/+/1035/ > > Discovered-by-KUnit: https://kunit-review.googlesource.com/c/linux/+/1035/ > Signed-off-by: Brendan Higgins [....] > + if (base_clk > ASPEED_I2CD_TIME_BASE_DIVISOR_MASK) { > + base_clk = ASPEED_I2CD_TIME_BASE_DIVISOR_MASK; > + clk_low = clk_high_low_mask; > + clk_high = clk_high_low_mask; Yes, it fixes these parameters to the lowest bus speed setting with the maximum base clock divisor value and the maximum SCL timing cycle value when a low bus-frequency is requested which exceeds the range of this H/W supports. This exceptional case handling is needed to prevent making invalid settings on it. Nice fix! One minor issue is, 'base_clk_divisor' instead of 'base_clk' could avoid misreading on this code. With that, it looks nice to me. Thanks! Reviewed-by: Jae Hyun Yoo