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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 91900C433F5 for ; Fri, 8 Oct 2021 08:47:37 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 5D20860F5A for ; Fri, 8 Oct 2021 08:47:37 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 5D20860F5A Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=mediatek.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=lists.infradead.org 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:MIME-Version:References:In-Reply-To: Date:CC:To:From:Subject:Message-ID:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=unJMmkjCu5Q2UMOa7+avkrRj/jVZj5bDf+OTX4VE8oM=; b=veSw1114DgyYLJ 0F/NSD0sjDyCIcMiHIHTQYK8w1vy78thR+l+reUv21woQFcVB6+9TLogXL/o3EsKZOWpkYWOWQMm+ Sna0Aq4BFkt3yg3fgjyPbuNvpaM+/g+Kows/hIsjvKQ5zagFl5/TBYUokiO/DG/VDsEwpV5yhjQ9h HFeeSnvKtxTJ7R6DwsNZubP0rpjSJ0E1SaCFdzB8qDONwUac+bzRpHdE9ELU6IRXJINsZSwJ2iPpf uccbfQK4ywZNTstrG2ZYwmTRwJPdMu8j5hqQwQTS06rqaovtOyU5I8jducQwGjR2o+Ix1P+BrRBQd WLEG7br+VjbrFR/RFPwQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1mYlXM-0025aB-JH; Fri, 08 Oct 2021 08:47:28 +0000 Received: from mailgw01.mediatek.com ([216.200.240.184]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1mYlX9-0025XE-8a; Fri, 08 Oct 2021 08:47:16 +0000 X-UUID: 12e00d9f7e184aa08ea87cb16d0d247d-20211008 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=mediatek.com; s=dk; h=Content-Transfer-Encoding:MIME-Version:Content-Type:References:In-Reply-To:Date:CC:To:From:Subject:Message-ID; bh=pUWaCMKNXz356vlGNAhNLBmgPI/6yLDLRRv6SApHeKk=; b=SSvR4da6L97hLsH633+rp84rPoV2cy9M97Oqe7lZeVhGoie9GRXamONxE/XVyryGAx68CITjjqYRvk5qykJQZqMFthfGGQhNPTBlYvaUh2XZoqK2kax/n0yswdfNgMRp5o6L9iIleR0OFyj80DJOdHHkjDTihG/PVcUncu9x67E=; X-UUID: 12e00d9f7e184aa08ea87cb16d0d247d-20211008 Received: from mtkcas67.mediatek.inc [(172.29.193.45)] by mailgw01.mediatek.com (envelope-from ) (musrelay.mediatek.com ESMTP with TLSv1.2 ECDHE-RSA-AES256-SHA384 256/256) with ESMTP id 879317550; Fri, 08 Oct 2021 01:47:12 -0700 Received: from mtkmbs10n2.mediatek.inc (172.21.101.183) by MTKMBS62N1.mediatek.inc (172.29.193.41) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Fri, 8 Oct 2021 01:47:10 -0700 Received: from mtkcas10.mediatek.inc (172.21.101.39) by mtkmbs10n2.mediatek.inc (172.21.101.183) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384) id 15.2.792.3; Fri, 8 Oct 2021 16:47:09 +0800 Received: from mhfsdcap04 (10.17.3.154) by mtkcas10.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.0.1497.2 via Frontend Transport; Fri, 8 Oct 2021 16:47:08 +0800 Message-ID: <1891acec7f5c417f62081a8b10249b265df7ea62.camel@mediatek.com> Subject: Re: [PATCH v7 6/7] i2c: mediatek: Isolate speed setting via dts for special devices From: Kewei Xu To: Wolfram Sang CC: , , , , , , , , , , , , , Date: Fri, 8 Oct 2021 16:47:11 +0800 In-Reply-To: References: <20210917101416.20760-1-kewei.xu@mediatek.com> <20210917101416.20760-7-kewei.xu@mediatek.com> X-Mailer: Evolution 3.28.5-0ubuntu0.18.04.2 MIME-Version: 1.0 X-MTK: N X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20211008_014715_328171_7207AF65 X-CRM114-Status: GOOD ( 13.68 ) X-BeenThere: linux-mediatek@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "Linux-mediatek" Errors-To: linux-mediatek-bounces+linux-mediatek=archiver.kernel.org@lists.infradead.org On Sat, 2021-10-02 at 08:40 +0200, Wolfram Sang wrote: > On Fri, Sep 17, 2021 at 06:14:15PM +0800, Kewei Xu wrote: > > In the commit be5ce0e97cc7 ("i2c: mediatek: Add i2c ac-timing > > adjust > > support"), the I2C timing calculation has been revised to support > > ac-timing adjustment, however that will break on some I2C > > components. > > As a result we want to introduce a new setting "default-adjust- > > timing" > > so those components can choose to use the old (default) timing > > algorithm. > > Why can't the new calculation be updated in a way that it works for > all > I2C components? > Hi, In the commit be5ce0e97cc7 ("i2c: mediatek: Add i2c ac-timing adjust support"), the I2C timing calculation has been revised to support ac-timing adjustment.But in our design, it will make tSU,STA/tHD,STA/tSU,STO shorter when the slave device have clock- stretching feature. Then we upload the commit a80f24945fcf ("i2c: mediatek: Use scl_int_delay_ns to compensate clock-stretching") to support adjusting tSU,STA/tHD,STA/tSU,STO when the slave device clock- stretching. But if the slave device stretch the SCL line for too long time, our design still cannot make tSU,STA/tHD,STA/tSU,STO meet spec. However in the old (default) timing algorithm before the commit be5ce0e97cc7 ("i2c: mediatek: Add i2c ac-timing adjust support"), tSU,STA/tHD,STA/tSU,STO can meet spec. So we want to define a new setting "default-adjust-timing" for using the old (default) timing algorithm. Thanks~ _______________________________________________ Linux-mediatek mailing list Linux-mediatek@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-mediatek