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=-14.0 required=3.0 tests=BAYES_00,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 D6790C433C1 for ; Fri, 26 Mar 2021 01:13:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AE9B261A2B for ; Fri, 26 Mar 2021 01:13:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230035AbhCZBNP (ORCPT ); Thu, 25 Mar 2021 21:13:15 -0400 Received: from mail-io1-f51.google.com ([209.85.166.51]:35768 "EHLO mail-io1-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229962AbhCZBNN (ORCPT ); Thu, 25 Mar 2021 21:13:13 -0400 Received: by mail-io1-f51.google.com with SMTP id x17so3838063iog.2; Thu, 25 Mar 2021 18:13:13 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=zbkw9Y7KdSrwPhBVHuNS2fuewhP21jNF8VYuw+vghOQ=; b=V1L7V/Y6RhjKv8lWnCsPdqkZMCcSgoWa7GFWJn1y/9gHUd+aTT8UkLRxz1Pxjk4OO3 vCOZze2nZ66+cInC7BGTaW0l0kRwHsdcGOdxw+Ucc1Y0WIuyDHJfwWlpsFuYEqJ9QVjI DMUI/8vRdcaEbxY6uFuwKOnR4o/JrEeWVKhRvWPtLjxBOrqJKIx+cndq1pUbdzBcAwBX Aecm8dHzb1P6AMAV+scGjhbv8kmFGojy7qABlS35+dDpdA0TKPdfGmXd7OacAGYQUwXq PsMDEQR1CeXoc8g0Zo+qbCOvvRyzDDOVWDNY5ECjxOD/C/nfMqKRHuE9TfTA8N6ViEHv thiw== X-Gm-Message-State: AOAM5339oy8yEcPqtrfl0IOyqeyjY+tFymQxd6USiBUPeZrnQX6sZ591 IbXrp7+UI3Zu3N+y7Ri7rA== X-Google-Smtp-Source: ABdhPJz/kkzII6gaHn1Zz42FMOTzrlw/itwIj30ByvIYMFs2vADjcapKqUr0+yzTejwVWkn/CIALjA== X-Received: by 2002:a05:6638:2101:: with SMTP id n1mr10049485jaj.7.1616721193112; Thu, 25 Mar 2021 18:13:13 -0700 (PDT) Received: from robh.at.kernel.org ([64.188.179.253]) by smtp.gmail.com with ESMTPSA id d2sm3490299ilm.7.2021.03.25.18.13.11 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 25 Mar 2021 18:13:12 -0700 (PDT) Received: (nullmailer pid 2102175 invoked by uid 1000); Fri, 26 Mar 2021 01:13:10 -0000 Date: Thu, 25 Mar 2021 19:13:10 -0600 From: Rob Herring To: Alain Volmat Cc: wsa@kernel.org, mark.rutland@arm.com, pierre-yves.mordret@foss.st.com, mcoquelin.stm32@gmail.com, alexandre.torgue@foss.st.com, linux-i2c@vger.kernel.org, devicetree@vger.kernel.org, linux-stm32@st-md-mailman.stormreply.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, fabrice.gasnier@foss.st.com Subject: Re: [PATCH v2 1/2] dt-bindings: i2c: stm32f7: add st,smbus-alert binding for SMBus Alert Message-ID: <20210326011310.GA2090957@robh.at.kernel.org> References: <1616075089-28115-1-git-send-email-alain.volmat@foss.st.com> <1616075089-28115-2-git-send-email-alain.volmat@foss.st.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1616075089-28115-2-git-send-email-alain.volmat@foss.st.com> Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org On Thu, Mar 18, 2021 at 02:44:48PM +0100, Alain Volmat wrote: > Based on the SMBus specification, SMBus Alert active state is low. > As often on SoC, the SMBus Alert pin is not only dedicated to this > feature and can also be used for another purpose (by configuring it > as alternate function for other functions via pinctrl). > > "smbus" dt-binding has been introduced recently [1], however it is also > used to indicate usage of host-notify feature. > Relying on 'smbus' binding for SMBus-Alert as well as it was discussed > previously [2] would lead to requiring the SMBALERT# pin to be configured > as alternate function for i2c/smbus controller even if only host-notify is > needed. > Indeed, not doing so would lead to spurious SMBus Alert interrupts since > the i2c/smbus controller would see the (not configured) SMBA pin as low > level. > > For that reason, SMBus-Alert needs to have its own binding in order > to only be enabled whenever SMBALERT# pin is configured as alternate > function for i2c/smbus controller. > > [1] https://marc.info/?l=linux-i2c&m=159531254413805&w=2 > [2] https://marc.info/?l=linux-renesas-soc&m=159361426409817&w=2 Please use lore.kernel.org links. > > Signed-off-by: Alain Volmat > > --- > v2: introduce st,smbus-alert property > --- > Documentation/devicetree/bindings/i2c/st,stm32-i2c.yaml | 5 +++++ > 1 file changed, 5 insertions(+) With that, Reviewed-by: Rob Herring Though I defer to Wolfram whether this could/should be common instead. Rob