From patchwork Thu Mar 18 13:44:48 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alain Volmat X-Patchwork-Id: 404311 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=-18.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT 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 960F7C4332B for ; Thu, 18 Mar 2021 13:46:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 53F8F64F1B for ; Thu, 18 Mar 2021 13:46:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230458AbhCRNpg (ORCPT ); Thu, 18 Mar 2021 09:45:36 -0400 Received: from mx08-00178001.pphosted.com ([91.207.212.93]:5322 "EHLO mx07-00178001.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S230517AbhCRNpR (ORCPT ); Thu, 18 Mar 2021 09:45:17 -0400 Received: from pps.filterd (m0046660.ppops.net [127.0.0.1]) by mx07-00178001.pphosted.com (8.16.0.43/8.16.0.43) with SMTP id 12IDfsx8014144; Thu, 18 Mar 2021 14:45:03 +0100 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=foss.st.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-type; s=selector1; bh=Mh1XkVMq3Xtlf2kfvBLiZv4WU5GJ6+7sEcK44RV22zs=; b=QULZ//VBLoES34B/3tASXpKg+U0hiF/0+LB/39QYzzufpbfUch4j0zUfP2bSknHlAIgC vQFXWGxXAMn6zVW2xFuxHfr3oTlkuXkEYV5o1xbP8fFWGiAfwaBCu4WOwDAg5VYmGhUL G2CKMHZMz78Cjqfa9YAay+6aGO3P3vcwE+q3CVplQWoyVXhtcVNMZ1mvPhCqloARWvo2 XqQxxlMrDYsCxdDu95ihbbFyHTa2BkJ65QvmwXDSc/AxJfrJ8+jO/rkttIBXwW/K3Qd7 Ca7vJtEeO1MAKsrJIVVa9Ncqi7zr+pfSPBs1YTNsVPjDpswwnsvLDGyCEx/OzO/bjqRp 7Q== Received: from beta.dmz-eu.st.com (beta.dmz-eu.st.com [164.129.1.35]) by mx07-00178001.pphosted.com with ESMTP id 37a8prbn29-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 18 Mar 2021 14:45:03 +0100 Received: from euls16034.sgp.st.com (euls16034.sgp.st.com [10.75.44.20]) by beta.dmz-eu.st.com (STMicroelectronics) with ESMTP id DAA0D100038; Thu, 18 Mar 2021 14:45:02 +0100 (CET) Received: from Webmail-eu.st.com (sfhdag2node3.st.com [10.75.127.6]) by euls16034.sgp.st.com (STMicroelectronics) with ESMTP id C67E52272B1; Thu, 18 Mar 2021 14:45:02 +0100 (CET) Received: from localhost (10.75.127.51) by SFHDAG2NODE3.st.com (10.75.127.6) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Thu, 18 Mar 2021 14:45:02 +0100 From: Alain Volmat To: , CC: , , , , , , , , , , Subject: [PATCH v2 1/2] dt-bindings: i2c: stm32f7: add st, smbus-alert binding for SMBus Alert Date: Thu, 18 Mar 2021 14:44:48 +0100 Message-ID: <1616075089-28115-2-git-send-email-alain.volmat@foss.st.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1616075089-28115-1-git-send-email-alain.volmat@foss.st.com> References: <1616075089-28115-1-git-send-email-alain.volmat@foss.st.com> MIME-Version: 1.0 X-Originating-IP: [10.75.127.51] X-ClientProxiedBy: SFHDAG2NODE1.st.com (10.75.127.4) To SFHDAG2NODE3.st.com (10.75.127.6) X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.369, 18.0.761 definitions=2021-03-18_07:2021-03-17,2021-03-18 signatures=0 Precedence: bulk List-ID: X-Mailing-List: linux-i2c@vger.kernel.org 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 Signed-off-by: Alain Volmat Reviewed-by: Rob Herring --- v2: introduce st,smbus-alert property --- Documentation/devicetree/bindings/i2c/st,stm32-i2c.yaml | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/Documentation/devicetree/bindings/i2c/st,stm32-i2c.yaml b/Documentation/devicetree/bindings/i2c/st,stm32-i2c.yaml index d747f4990ad8..0d45ead7d835 100644 --- a/Documentation/devicetree/bindings/i2c/st,stm32-i2c.yaml +++ b/Documentation/devicetree/bindings/i2c/st,stm32-i2c.yaml @@ -36,6 +36,11 @@ allOf: minItems: 3 maxItems: 3 + st,smbus-alert: + description: Enable the SMBus-Alert via SMBA pin, note SMBA pin + must also be configured via pinctrl. + type: boolean + - if: properties: compatible: