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 E77B8C433EF for ; Mon, 16 May 2022 07:57:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237380AbiEPH5g (ORCPT ); Mon, 16 May 2022 03:57:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45126 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232688AbiEPH5f (ORCPT ); Mon, 16 May 2022 03:57:35 -0400 Received: from EUR02-HE1-obe.outbound.protection.outlook.com (mail-eopbgr10124.outbound.protection.outlook.com [40.107.1.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3E83EDF52; Mon, 16 May 2022 00:57:32 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=LNXDuuQbGpGChOhj9cDdIT37qBKqKY9KIguy2Zqo8KxEqN5p5thx2ttvvmlH3c0rocrpFbnW5PC1eJD5UIZ8FeSZxUOgIh4QjNzJK5D5Jalvh4+NM55vLwTQ5k0rP6HV0n5gHC6QIsyj4OYsr6LgcFzUMpwf5Ayw9cpRSAAxMJtYeQd5i/sor/YeO3jcxI2fEgqryaPcM7LQ00yoSLvJej6BMjoWr50UDfaEK/FesdTxGL+mNfdLodIQk2nQs+SMSACBv4lkLAzPEJzJUyBPQp4plWMJ1Y8Ux24ZMkH5HNoxmnn/bBjhjUhNRTOx3h7AU17cE4mMCiSCCfXn5a/XeQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=ki9WpyuLfaT95UZh2w9SoTuS4dOD8CuOkUEvRX1vDQY=; b=HbtOSqvb4bgoOvNRYtpQX1z/VH/S94xSLttT6NZGJP0CHcui0kbB6ZwUDVfDScVwcjtq3NeY99WlQ0mnGfgMQ1xv2VayAhPrnXekYRwC/6ahx/vQB1ATKBQCAK4fMQpDgNy+8f/gc4EP1DpIi3+xSD2DfBjaDQ9SMaedeJatDyx3V626nxcuQ75EanmmWnnoTELWF5sPUQr7lW+jsygk1VKfxJMIUAapz6dsN6vDRx9GF55L9OISrlVCMg3Thw11VJrCRmU4nlSukFeZ0gWbKNaf23t/0Fm6l6XOZ5NqtUIgQayCdHXbrJK1D4mTC2yEIsO//o97GJ8zRIj9a4DEkQ== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=axentia.se; dmarc=pass action=none header.from=axentia.se; dkim=pass header.d=axentia.se; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=axentia.se; s=selector2; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=ki9WpyuLfaT95UZh2w9SoTuS4dOD8CuOkUEvRX1vDQY=; b=N3o/NfXnixwtywaqN5VzBEkA9qtBmsDwervtU9N8pSbyXbg/Z29s5oP9eQK0EPGJIWWJ/eRwhLaSeRtMc4vreDvhvw7Cv7EZW354EoRmqCZ/zHPfcOiN+LLFqIYuNEFqbsoyVLWvYVUJmaqJBj6COxbclLbecNmvnuKkAOAZD0A= Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=axentia.se; Received: from AM0PR02MB4436.eurprd02.prod.outlook.com (2603:10a6:208:ed::15) by VE1PR02MB5680.eurprd02.prod.outlook.com (2603:10a6:803:10d::11) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.5250.18; Mon, 16 May 2022 07:57:26 +0000 Received: from AM0PR02MB4436.eurprd02.prod.outlook.com ([fe80::dcef:9022:d307:3e8a]) by AM0PR02MB4436.eurprd02.prod.outlook.com ([fe80::dcef:9022:d307:3e8a%4]) with mapi id 15.20.5250.018; Mon, 16 May 2022 07:57:26 +0000 Message-ID: <7ab1f387-3670-4b49-211d-3ff9a7c3d40b@axentia.se> Date: Mon, 16 May 2022 09:57:24 +0200 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.9.0 Subject: Re: [PATCH v2 1/2] dt-bindings: i2c: add property to avoid device detection Content-Language: en-US To: Wolfram Sang , Vincent Whitchurch , kernel@axis.com, linux-i2c@vger.kernel.org, devicetree@vger.kernel.org, krzk+dt@kernel.org, robh+dt@kernel.org, linux-kernel@vger.kernel.org, luca@lucacressoli.net References: <20220412085046.1110127-1-vincent.whitchurch@axis.com> <20220412085046.1110127-2-vincent.whitchurch@axis.com> From: Peter Rosin In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-ClientProxiedBy: GV3P280CA0048.SWEP280.PROD.OUTLOOK.COM (2603:10a6:150:9::29) To AM0PR02MB4436.eurprd02.prod.outlook.com (2603:10a6:208:ed::15) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id: 324eaffc-dc94-4a7d-0a2b-08da3711b7e8 X-MS-TrafficTypeDiagnostic: VE1PR02MB5680:EE_ X-Microsoft-Antispam-PRVS: X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:AM0PR02MB4436.eurprd02.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230001)(39830400003)(376002)(366004)(136003)(346002)(396003)(186003)(2616005)(8676002)(5660300002)(26005)(6512007)(316002)(66476007)(6486002)(6506007)(966005)(8936002)(508600001)(2906002)(38100700002)(86362001)(36756003)(66556008)(66946007)(41300700001)(31696002)(83380400001)(31686004)(110136005)(45980500001)(43740500002);DIR:OUT;SFP:1102; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?REtWV1NIL0pZMmFZbG9JWVZMY1Brd0xGYkpsSGhJVk9BTWZwYnEzQUxWT1Fr?= =?utf-8?B?MXJHU2s3MUV2V250YWxWWEN4OFFzSmRTS0RxZEtsaEdXMTQrMXZTbmRKM25R?= =?utf-8?B?VFJJd0E3RWF2WEU2S29ULzZtS0U5Q3JiclZGNVNRb0w2aU9VSDA0UDJBVGps?= =?utf-8?B?WStxVEFvN05lZ2VOeVg0VTYrZXlENTB3UDhaRXhBSHBHcUR4elk0bFhPQmpS?= =?utf-8?B?eXZHRXJBdWJkY3dBKzgwbTN6YUFnZzJaUXpvOHB4V0xkWUVZaU9PUytSeE5C?= =?utf-8?B?Z0ZvbWlKeTRiN01Ea0RKSWhDOGxTVzdtK3BTTWVEeFdOTVlrMU5wWlpNaE80?= =?utf-8?B?NFFsNGFjRlBDazN0N2xoT1JLSUtweTRLV004NDAxQWswMHJNZkp1cHA1dDc2?= =?utf-8?B?dllXbkNVUk1keUlMNEZrU0k2YWxCVW9xWVR3aGhHbHRadGtDZEk3Vll2dFVQ?= =?utf-8?B?VWdhUVAyUllHOFhFNTF4SjRRaTVuTkRyUVpMTnJBU2F2ajc1QldTWFhkd2hB?= =?utf-8?B?VUphNlg5aHJCOGJtcUVCMW1hQyswaWwvSTNEMTNGT1hHdC94VVVWdmFCeTMw?= =?utf-8?B?SkhySUZuSUtxQ2pIUC9YdENkelNXalZJSjNra3phWUdWSzZmREFlVmsrU2lF?= =?utf-8?B?VmJ4dnBTQm1aVExVYzRXMWc0RzZXenJaNUkwZ201L0wxN0JPMEZsK0I2Y2JV?= =?utf-8?B?azZTWUNtNGFVNm1iYW85RWV1OWZUcVBDQXJiU1RndXJyVFZRMFNzQkY5UDBD?= =?utf-8?B?Rm9NVkVTTTVZR2J6V0tFWC9jbTZYRlloUmozTjFpdnpXcGdTVG84ditMMGhZ?= =?utf-8?B?VCtGVE1BS0x5OEIwWUJqNWVCcFZEakZZU2FXM3VIS083VlVsZmVQcTliOWlX?= =?utf-8?B?eDZJMHBUNVlkTFJrUnBXTk1ocjhRdFRnM1hLSHJ5czdVNldkbEhGSXExNzAw?= =?utf-8?B?by81aHI2d250UkVjZFVIY0p2SGFZWEN0WVZWZW5WZnRXY1V3a1lqa2w0VmtB?= =?utf-8?B?QkxERFRhS3J1QWNtWFRoYVc4cmFIcjJNMXpGTFpXVEtqbm51ZVY4V2YyZWhn?= =?utf-8?B?T0lvR3ZJY21sNjVtTUppY1hEK29UR0RTRHpUZm9hdzh1QkhxdlZBcWFEelJP?= =?utf-8?B?RGQwRzk2YVBsTllyQ2l5TWxpTVNOdkxkeis3dVcwcWphUjYzQjRqWThTdnZC?= =?utf-8?B?c0VQd2ZGL0ZnOVhhWWZ2am5UNWEyK016MUVJSTlKUGt2N3Z1SGpBOU9yZ3px?= =?utf-8?B?R3Q1Q0k3OHRYbDlpSy8xSU1ZWkpWbmdJUm1sQ20vaFJUa0h3VHpXenVkSmdN?= =?utf-8?B?RW0ybjVuaURzYWRReUdQR1JLbkowdGpjeEVncUZWdzVrVnJKT3pJSEc2WDdi?= =?utf-8?B?NVBjcmROWk45dS9KNGhhVUtpbXh1T3cybjZDOFQ3Y0R4dTR5Njk2bXptQTB6?= =?utf-8?B?a1grZzRVajFNS25ZRHZ4RjZRUm5KQlFZcTFnYTI1ajAxYzN6N2tUUEFNanQr?= =?utf-8?B?WVMxUDFNZ3dlRzU0bVRZYTZ1cFdsY2RlMFBHcVJacHk3UUF6N3V1ZHNweWJX?= =?utf-8?B?YmpOdnhWamhPRUlVbGU4T1RWRnVsVThXY005QUNuRnRHdTlES2NKaGppUDZi?= =?utf-8?B?TGN4YkNRK3ExdFlsZUw3T0RxeDBHaHRJRHlPVnBjaCtLOHFaenFQMzBXL2di?= =?utf-8?B?WFlYZ3ZlM1hOUlJsK2JlcXMrMGtNZVMvV2hIaW5BMmRtQ2o3UHdWQnF2dzZ5?= =?utf-8?B?ejI4U05NNHpERnR4QU8ycmIxZGhsZXhQbXFrZFBYdjNlcTZBZDYrd3NNTlVU?= =?utf-8?B?K2JtT2RQNVYvSjFqVjBYTXJIT3BqOGJnUHprVXRWdnVmYU9hYjl4N2Mycmdl?= =?utf-8?B?NjYyRUFoVEx4cEdBNGwxM1RSVEltaCszQ0NXRi9LdHg4MXFSNFVnZ2ZtSHhO?= =?utf-8?B?d0ltTmxvSHYraGxKWEkvbUcycTZQVlpRb0J3Y0JmTENoWnpBa0g3S2ZMV28x?= =?utf-8?B?ZVVTbXg0SFNvZk1mcDAxT2YrelIvQkJNY2crR1RNckxnU09CMVZlbStVVXcy?= =?utf-8?B?cWxCOFV6TWh3aTFxUlVvWkRWYjBCdEFLUU92dEpkNEtab21pYWI3a3EwRUVN?= =?utf-8?B?cUZuVGJMQWdVZy9INnZMSEJyVTRmTnlVYzNXOWd5clVSamZ1VW9MZ01YRE9j?= =?utf-8?B?ZUw4NENORDdzYjZYN3BvNFp6eDlZbzFQSFlyVEJ6OFdSMGJsL2VscVI1L0dy?= =?utf-8?B?Vk5RV1hnRjY1NnAxVGJSNGxWVnN2U3lzd2ZvSzNJZFZqVVRITUxPUUNHUjFY?= =?utf-8?B?OXBHOG8zT2JPOFpOcTVYWHMzYXh5L3N2L0RhYVV0eDBKQ3VJTUNBdz09?= X-OriginatorOrg: axentia.se X-MS-Exchange-CrossTenant-Network-Message-Id: 324eaffc-dc94-4a7d-0a2b-08da3711b7e8 X-MS-Exchange-CrossTenant-AuthSource: AM0PR02MB4436.eurprd02.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 16 May 2022 07:57:26.7005 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 4ee68585-03e1-4785-942a-df9c1871a234 X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: uWNZsW3FZbGVEBOf8Ot4zH94X/DWDg2LmA2i8sCS+xCVKp35M3EaYKWL+ClYqO5C X-MS-Exchange-Transport-CrossTenantHeadersStamped: VE1PR02MB5680 Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org 2022-05-14 at 16:26, Wolfram Sang wrote: > On Tue, Apr 12, 2022 at 10:50:45AM +0200, Vincent Whitchurch wrote: >> When drivers with ->detect callbacks are loaded, the I2C core does a >> bunch of transactions to try to probe for these devices, regardless of >> whether they are specified in the devicetree or not. (This only happens >> on I2C controllers whose drivers enable the I2C_CLASS* flags, but this >> is the case for generic drivers like i2c-gpio.) >> >> These kinds of transactions are unnecessary on systems where the >> devicetree specifies all the devices on the I2C bus, so add a property >> to indicate that the devicetree description of the hardware is complete >> and thus allow this discovery to be disabled. > > Hmm, I don't think the name is fitting. "no-detect" is the desired > behaviour but a proper description is more like "bus-complete" or > something? > > That aside, I am not sure we should handle this at DT level. Maybe we > should better change the GPIO driver to not populate a class if we have > a firmware node? We also have the somewhat related address translation case (which I still need to look at). [Adding Luca to Cc] https://lore.kernel.org/lkml/20220206115939.3091265-1-luca@lucaceresoli.net/ If a bus is "bus-complete", then address translation could use any unused address instead of from an explicit list of addresses. I.e. the "i2c-alias-pool" in the binding in patch 4/6 of that series could be made optional if the bus is "bus-complete". Not sure how much value there is in that? Cheers, Peter