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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D5651C43217 for ; Mon, 7 Feb 2022 14:36:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344128AbiBGOgk (ORCPT ); Mon, 7 Feb 2022 09:36:40 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58248 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1391021AbiBGOIg (ORCPT ); Mon, 7 Feb 2022 09:08:36 -0500 Received: from mail-lf1-x134.google.com (mail-lf1-x134.google.com [IPv6:2a00:1450:4864:20::134]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7B15FC03FEC6 for ; Mon, 7 Feb 2022 06:08:29 -0800 (PST) Received: by mail-lf1-x134.google.com with SMTP id u6so6066592lfc.3 for ; Mon, 07 Feb 2022 06:08:29 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=fLhp+WWUm1vVXS5XWMKEtv0+L1QgW8Rkp/k7i+gibrs=; b=MSuqqIF5LI72mYLzJaJPbv0ML26XhrEI3+Js/u5uNtPisvYGis6UxutY+EziIH7xXb 5DnKb+IxWH1XIfbLz3oP04dPWLg2WFRAs2oMgBKkCycXMQF9xRhAZW57gc0thQE11ZJl h/OHTXfotsK8zM+Jahgem9vxDtqJbslSode/na37fmosQblelrm6+lXWdjGX86t811vQ uiY8QnVDepzvCeruhnbV1e8Sw2DYnvutsPA+GqtHfh+WfYWLuLdEMP4QMkEVUjLydgz8 g4MYOQ3KPgM/lWJvyE6tU4Ag8n5wnNfGidUEa5GYFXv50HL/aqOulQE451Cc/jJ2YT27 DulQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=fLhp+WWUm1vVXS5XWMKEtv0+L1QgW8Rkp/k7i+gibrs=; b=0G608y3vXueIXhaap7nZdW2NF6y2CU8lta3qhxkE3NT7pbZeHKeMwVaCd1Av+s64Ss ++gL0yI1tQrBW6b7XBrRhK3jKwDNIXnoaA74NpnipbjEZV5TMcYK073TQYLWlpg/wUM4 CygzQ9s773twR/o57Fl3ni+KpWIJqioxulH14CrOYqQQIIanSLQEEbL25g100fXmF49Q Cq/3InYzKhLy9Y286RK4QyJOm/Y8UGOBpg8Luc515XqWRPGrv11f7bEk30ZJck4L1go3 iIEtiz2d5W8ZdUmSBu4lZHR0+tDuYfHSefuCZ295q+VGtOKXtpna99nedDToa8acGz6b dzPQ== X-Gm-Message-State: AOAM532g5EZXdrCleEdD6BWp9rsLnrKUVveAJu0er4iaRr+f+en28Kzj MUAdkysFLszODP4tYD16WJmpng== X-Google-Smtp-Source: ABdhPJy0awm/eN/ckVzUS1VOXJf7aP/mshK1zmoOblk/KvzKdLmKpxuXzvyZv2bVR/T0LfwdSgkMfw== X-Received: by 2002:a05:6512:3b9a:: with SMTP id g26mr8515824lfv.71.1644242907805; Mon, 07 Feb 2022 06:08:27 -0800 (PST) Received: from [192.168.0.102] ([217.71.236.28]) by smtp.gmail.com with ESMTPSA id f21sm1504616lfg.300.2022.02.07.06.08.27 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 07 Feb 2022 06:08:27 -0800 (PST) Subject: Re: [PATCH 2/9] dt-bindings: i2c: qcom-cci: add description of a vbus-supply property To: Mark Brown , Bjorn Andersson Cc: linus.walleij@linaro.org, Loic Poulain , Robert Foss , Rob Herring , Wolfram Sang , linux-i2c@vger.kernel.org, linux-arm-msm@vger.kernel.org, devicetree@vger.kernel.org References: <20220203164629.1711958-1-vladimir.zapolskiy@linaro.org> <20220203164629.1711958-3-vladimir.zapolskiy@linaro.org> From: Vladimir Zapolskiy Message-ID: <846cdc17-891d-2ee4-fc89-7cf6fbdebc1d@linaro.org> Date: Mon, 7 Feb 2022 16:08:01 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.6.1 MIME-Version: 1.0 In-Reply-To: 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 Hi Bjorn, Mark, On 2/4/22 9:32 PM, Mark Brown wrote: > On Fri, Feb 04, 2022 at 11:02:04AM -0800, Bjorn Andersson wrote: >> On Fri 04 Feb 10:42 PST 2022, Mark Brown wrote: >>> On Fri, Feb 04, 2022 at 10:05:47AM -0800, Bjorn Andersson wrote: > >>>> Typically we don't don't mention the bus-supply because it happens to be >>>> pulled up either by io-supply for the block, or by some always-on >>>> regulator in the system. > >>> If the bus is being pulled up to some supply other than the supply that >>> the bus is referenced to that doesn't sound like the greatest electrical >>> engineering ever... without any context it's hard to comment about this >>> particular system. > >> That's what the schematics says... > > Oh, good. I forsee no problems here. Probably this is something that > should be in the I2C core if it's going to be dynamically managed, > though just setting the supply as always on is probably more expedient. > vbus-supply property has been added recently to another I2C master controller, see commit c021087c43c8 ("dt-binding: i2c: mt65xx: add vbus-supply property"). It serves right the same purpose, and its handling is going to be done in i2c core, however since the latter is not yet completed, I would propose to add the property to i2c-bus subnodes of QCOM CCI and its support in the driver, later on both the property and its generic support would be better to see in i2c core. -- Best wishes, Vladimir