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 X-Spam-Level: X-Spam-Status: No, score=-5.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,UNPARSEABLE_RELAY,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 44199C43462 for ; Fri, 2 Apr 2021 15:30:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0440C61158 for ; Fri, 2 Apr 2021 15:30:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235755AbhDBPak (ORCPT ); Fri, 2 Apr 2021 11:30:40 -0400 Received: from out28-172.mail.aliyun.com ([115.124.28.172]:56979 "EHLO out28-172.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235248AbhDBPak (ORCPT ); Fri, 2 Apr 2021 11:30:40 -0400 X-Alimail-AntiSpam: AC=CONTINUE;BC=0.1216449|-1;CH=green;DM=|CONTINUE|false|;DS=CONTINUE|ham_news_journal|0.00690669-0.000830163-0.992263;FP=0|0|0|0|0|-1|-1|-1;HT=ay29a033018047209;MF=zhouyanjie@wanyeetech.com;NM=1;PH=DS;RN=9;RT=9;SR=0;TI=SMTPD_---.JuCJUHM_1617377433; Received: from 192.168.88.133(mailfrom:zhouyanjie@wanyeetech.com fp:SMTPD_---.JuCJUHM_1617377433) by smtp.aliyun-inc.com(10.147.40.26); Fri, 02 Apr 2021 23:30:33 +0800 Subject: Re: [PATCH] I2C: JZ4780: Fix bug for Ingenic X1000. To: Wolfram Sang Cc: paul@crapouillou.net, stable@vger.kernel.org, linux-mips@vger.kernel.org, linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org, dongsheng.qiu@ingenic.com, aric.pzqi@ingenic.com, sernia.zhou@foxmail.com References: <1616084743-112402-1-git-send-email-zhouyanjie@wanyeetech.com> <1616084743-112402-2-git-send-email-zhouyanjie@wanyeetech.com> <20210318170623.GA1961@ninjato> <644d19d8-9444-4dde-a891-c9dfd523389e@wanyeetech.com> <20210331071835.GB1025@ninjato> From: Zhou Yanjie Message-ID: Date: Fri, 2 Apr 2021 23:30:32 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 MIME-Version: 1.0 In-Reply-To: <20210331071835.GB1025@ninjato> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org Hi Wolfram, On 2021/3/31 下午3:18, Wolfram Sang wrote: > Hi, > >>> Any write operation? I wonder then why nobody noticed before? >> >> The standard I2C communication should look like this: >> >> Read: >> >> device_addr + w, reg_addr, device_addr + r, data; >> >> Write: >> >> device_addr + w, reg_addr, data; >> >> >> But without this patch, it looks like this: >> >> Read: >> >> device_addr + w, reg_addr, device_addr + r, data; >> >> Write: >> >> device_addr + w, reg_addr, device_addr + w, data; >> >> This is clearly not correct. > Thanks for the additional information! I understand now. I added a bit > of this to the commit message of v2 to explain the situation. > Thanks! Best regards!