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=-8.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable 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 BA345C4741F for ; Fri, 30 Oct 2020 14:48:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6BC272075E for ; Fri, 30 Oct 2020 14:48:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726545AbgJ3Osf (ORCPT ); Fri, 30 Oct 2020 10:48:35 -0400 Received: from mga03.intel.com ([134.134.136.65]:38461 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726239AbgJ3OrB (ORCPT ); Fri, 30 Oct 2020 10:47:01 -0400 IronPort-SDR: MYes1HbQxGgmM41l95aX8YwVuh1tfsxeQCboDVSBAEGIm0oLpRkgxTPWfG02Kvs7DojbhYuQ94 Axr1IMy/RzRA== X-IronPort-AV: E=McAfee;i="6000,8403,9789"; a="168712021" X-IronPort-AV: E=Sophos;i="5.77,433,1596524400"; d="scan'208";a="168712021" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 30 Oct 2020 07:46:05 -0700 IronPort-SDR: JFvH7no/9HmOkEt0yQULlmCJZDuhjNnU/TSiSzPDvyqnNz1LgU7P1Fjl1F4JIqA0/hpVlmtQyN 66OYUgcPkH+g== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.77,433,1596524400"; d="scan'208";a="356609975" Received: from mylly.fi.intel.com (HELO [10.237.72.73]) ([10.237.72.73]) by fmsmga002.fm.intel.com with ESMTP; 30 Oct 2020 07:46:03 -0700 Subject: Re: [PATCH 2/2] i2c: designware: slave should do WRITE_REQUESTED before WRITE_RECEIVED To: Michael Wu , Andy Shevchenko , Mika Westerberg , Wolfram Sang , linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Morgan Chang References: <20201030080420.28016-1-michael.wu@vatics.com> <20201030080420.28016-3-michael.wu@vatics.com> From: Jarkko Nikula Message-ID: <85c6cb3f-2eeb-07c7-0a53-a502b45c91a5@linux.intel.com> Date: Fri, 30 Oct 2020 16:46:02 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.12.0 MIME-Version: 1.0 In-Reply-To: <20201030080420.28016-3-michael.wu@vatics.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-i2c@vger.kernel.org On 10/30/20 10:04 AM, Michael Wu wrote: > Sometimes we would get the following flow when doing an i2cset: > > 0x1 STATUS SLAVE_ACTIVITY=0x1 : RAW_INTR_STAT=0x514 : INTR_STAT=0x4 > I2C_SLAVE_WRITE_RECEIVED > 0x1 STATUS SLAVE_ACTIVITY=0x0 : RAW_INTR_STAT=0x714 : INTR_STAT=0x204 > I2C_SLAVE_WRITE_REQUESTED > I2C_SLAVE_WRITE_RECEIVED > > Documentation/i2c/slave-interface.rst says that I2C_SLAVE_WRITE_REQUESTED, > which is mandatory, should be sent while the data did not arrive yet. It > means in a write-request I2C_SLAVE_WRITE_REQUESTED should be reported > before any I2C_SLAVE_WRITE_RECEIVED. > > By the way, I2C_SLAVE_STOP didn't be reported in the above case because > DW_IC_INTR_STAT was not 0x200. > > dev->status can be used to record the current state, especially Designware > I2C controller has no interrupts to identify a write-request. This patch > makes not only I2C_SLAVE_WRITE_REQUESTED been reported first when > IC_INTR_RX_FULL is rising and dev->status isn't STATUS_WRITE_IN_PROGRESS > but also I2C_SLAVE_STOP been reported when a STOP condition is received. > > Signed-off-by: Michael Wu > --- > drivers/i2c/busses/i2c-designware-slave.c | 45 +++++++++-------------- > 1 file changed, 18 insertions(+), 27 deletions(-) > Acked-by: Jarkko Nikula