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 BD51EEB64DC for ; Mon, 10 Jul 2023 19:10:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232278AbjGJTKe (ORCPT ); Mon, 10 Jul 2023 15:10:34 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59752 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232749AbjGJTKR (ORCPT ); Mon, 10 Jul 2023 15:10:17 -0400 Received: from EUR03-AM7-obe.outbound.protection.outlook.com (mail-am7eur03on2042.outbound.protection.outlook.com [40.107.105.42]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F18C02724; Mon, 10 Jul 2023 12:09:14 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=fWDALgY+tisPHc54uZoALLcIRiytaEAPYHg2z1Q0WTE7pQ1aOBnBPR3SGWL22Gbp1VROIH0qmiCZ8IEb/8V3YSyjZlaebyxu8ZEY5oy/Uk9JMss/U2iRyxIpCvb5EehjdVJv6ueh8hDManPEK4yaiLdq50VaP8YA+JuhiE4su5ajZ281VKggkpXulBm9UyTLhICbRyE+V1PGXz5Y3LRgNE7jhEoRxjU6HnGbp/rahlQh+gkbfUiuozT/YvLZ7DuBoV3KNLcHo5dH/XqnaFkRn030JDQM8xyEvbF0rQ9J5+Vh0RGy2MY5U79QPc3bDH41MUL+G7/9GOEOcY6VMLf2PQ== 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=/xn52Nz2hwmNiY7UxuvErayOMCOGNFhjZlrYQ4+VpLI=; b=ZxPxIkQGsG+rVyTIVZUBfoZy7hxlNej44esXaWQHkRO6Dqdu0M3w+SH1R1JOqVM5W1Y2hsCUY1EjEDpcEVHk8ZEO73xGnaEhegWBmr3HIcxCo2x7rkZytgHn9i9WXFU6vbEStIxt5+tCQ9H9IrfH7Mt16s7UyZvNPd0Im+IhOiFuCgK1MM6NZoLsjuMAU8TXRujBltco8s+a6d9BJYOslnHH4DaL7v++PTPtNmKAfRF/CAuRhaVn4CYy6vk8LNBXVt7HewQSSI4fuVvfB0HdjrHbjxni4VzPRGYtG11oahiIqYRw2QVbh1Mdev+q6Bgvt/8V5Z4jIqB8O5fBc369xA== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=vaisala.com; dmarc=pass action=none header.from=vaisala.com; dkim=pass header.d=vaisala.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=vaisala.com; s=selector1; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=/xn52Nz2hwmNiY7UxuvErayOMCOGNFhjZlrYQ4+VpLI=; b=QoJig4Rqf6I0ZnqgOGLlfrmllzROoTEl+nGpk3x2ZJOgOTA3jRt8U/U7ytrGKTU6ynGevrJPlJDSizO4FoT49632VWoaBekxpk/WOZuXgt/2uIow6wh78W/LUvsvq9y0GcF7MlZdKdEuUw9y7KEBrgCAN1taDrvcme9WsZPZfHwn+/0iduvCIOZm5u2v18KUNvUVxR+warTdJbtdPBkvucAFVO34ib1OqfKjEHmm7MvJ2UCdGfJkMNxtjXmJu+uPoe79x2R4Ze7AZHA6u0GJQEjFIlTreMbZ83S3rhHFM4DHPtpAfNRWhtrDYeB1SEnGpbjgtnIycjGxUAwhrnFOzw== Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=vaisala.com; Received: from HE1PR0602MB3241.eurprd06.prod.outlook.com (2603:10a6:7:17::28) by AS8PR06MB7958.eurprd06.prod.outlook.com (2603:10a6:20b:3c1::12) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.6565.30; Mon, 10 Jul 2023 19:08:36 +0000 Received: from HE1PR0602MB3241.eurprd06.prod.outlook.com ([fe80::8413:b7d5:15ac:63a3]) by HE1PR0602MB3241.eurprd06.prod.outlook.com ([fe80::8413:b7d5:15ac:63a3%3]) with mapi id 15.20.6565.026; Mon, 10 Jul 2023 19:08:35 +0000 Message-ID: <87fac0dd-9a97-b188-4887-8c4bb21196d5@vaisala.com> Date: Mon, 10 Jul 2023 22:08:32 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.11.0 Subject: Re: [PATCH 0/2] net: phy: dp83822: Add support for line class driver configuration Content-Language: en-US To: Andrew Lunn Cc: "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Heiner Kallweit , Russell King , Andrew Davis , netdev@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org References: <20230710175621.8612-1-vesa.jaaskelainen@vaisala.com> <261cb91c-eb3a-4612-93ad-25e2bc1a7c23@lunn.ch> From: =?UTF-8?B?VmVzYSBKw6TDpHNrZWzDpGluZW4=?= In-Reply-To: <261cb91c-eb3a-4612-93ad-25e2bc1a7c23@lunn.ch> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-ClientProxiedBy: GV3P280CA0030.SWEP280.PROD.OUTLOOK.COM (2603:10a6:150:b::35) To HE1PR0602MB3241.eurprd06.prod.outlook.com (2603:10a6:7:17::28) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: HE1PR0602MB3241:EE_|AS8PR06MB7958:EE_ X-MS-Office365-Filtering-Correlation-Id: c57f02ea-6788-4c04-9534-08db81790f3d 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:HE1PR0602MB3241.eurprd06.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230028)(4636009)(39850400004)(346002)(376002)(366004)(396003)(136003)(451199021)(186003)(26005)(6506007)(2616005)(966005)(6512007)(66574015)(83380400001)(41300700001)(4326008)(6916009)(66556008)(316002)(2906002)(7416002)(5660300002)(66476007)(8676002)(66946007)(8936002)(478600001)(6486002)(6666004)(54906003)(85202003)(85182001)(36756003)(31696002)(86362001)(38100700002)(31686004)(43740500002)(45980500001);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?aWxPdUl0WkRJQzJzQnUxU1ZMRU85RTEzQUZHWURFaDBCYTlkV05MM2JSV1VX?= =?utf-8?B?bHNyVlh0SUJ6TkJpdFhQeVlTVW5FeVdmeVpyTjdMaDk1U05EZC9nUG5xYWhy?= =?utf-8?B?bitDbmI0Q2FNaHFOVVBpdGVIcktJVzdVaFh0RlhkVmV0YkRWVVlSMWVDSStq?= =?utf-8?B?VERVcDlCdnQrU0M1NGt5ODIvc2RJWVVtZm5tYWVPVEpGbWdObXMzeVBqaUYy?= =?utf-8?B?b3FRMGNKV1F6YUdPTGd5TTNsK0E2MTlYSFRFNUxSZEM0YzdxYXNrVDNBdGdh?= =?utf-8?B?dzVBeGMwaXgraUxNU3d3ZlZGaVR0cXJIT1ZMZVFYYXFIOGcxc0paTk5pcll6?= =?utf-8?B?NkdESkhmb1pjM1M1M0JtSXJTRERUbkZNQ3BpdmhDYVUyL0tBK3pxNXBtVlg0?= =?utf-8?B?RTQyazBHUG9qWWxHUEVUS2lQcy9ZWktwRWMxRTJjSmR4RGprSjlPYnZ3MGZy?= =?utf-8?B?M2JXcXFHVlBKb0xPTy9CWU9TMVk3dzAyRDhWN0cvNWNuQlY1bytEOXE1czhs?= =?utf-8?B?dGZPZkRpTW9kVUY3bWRqNzV0UzMrZmQwcnRwT0t5V1daN3REcUY2Sld4T0lj?= =?utf-8?B?ZVhnTmFnRFh6OU50QWJSbXcxdWIvUHdQbkRSRHc3OWRqN3Z4S3JyWXpvN1Vs?= =?utf-8?B?RWwwcGYvTjVNT0JRNXRQaGQra2RPMlRTZnJvS0w1QWdaVm9uUG92dkZ4QVVo?= =?utf-8?B?bUFZaW1VV3RlZjJncUhnYm5vMENWK2daRnVlTk9DbCswWjA0Um92ZG9tc2JU?= =?utf-8?B?dzRzZlB0cDlKMEFlZmhTQ3N3ZFZpUEU3RERacldiaWFpUUkxY2Q3cWpQQk04?= =?utf-8?B?Z0hMVThTcjZNVnNCQ0ZNT1dVZTJLQXFOOW9pWmtkYWJmU3NzVWU5dldkNm94?= =?utf-8?B?UVhvSlhpYlFEemFmZzJkekgwQ2ZqdFMwZ2NwY1pDMC92ckxHNWNpOVRsa0dw?= =?utf-8?B?VVhCNUlGKzMyYWtrUkU4Mm9VZ1YxbFd6U1FoZlNBdEU3ZVNXSjlMMEdyaWZ6?= =?utf-8?B?bitkYXJZa2Rwa2pxQlJGbHFZcmRsUG84bGo3Ti8zblVVb2d5VlQxOHlIVmQ0?= =?utf-8?B?OVIvWW1TdW9XSFFESXc3ZmxwTjMyZUluQ3RLK2VmQ3NZNkpHc1pOWDRCQWwr?= =?utf-8?B?SmZ3U3ZMUWsyYlo1Ylk5WXJNYUU1Z3VLQ3dKV0FqdEc3Y3JaejloRUEzN2I1?= =?utf-8?B?TlVBOHVrT3YzVTE5dWJMRFBtOEwwRGx1OVNkYTdnN014czB5WlU1K3NQWXJV?= =?utf-8?B?SWRNeG9uaGMwQUg2bTVyM1hld0szT3B0Z0IxL0QwUWNUQklVazAramFUS3ZF?= =?utf-8?B?dWo1NmxjZUlyRTJ3SHRBSDY3OHRhT0wyWk5GYm9GR2JEVmwxY3I3RnllSWho?= =?utf-8?B?R0s1bVhwZ0tCTVo1eFgxTlVoUkdZNnNqeXFCRkZwc3FlN0swbWJRL0xnRGxy?= =?utf-8?B?d2RFbTdXMHltTjhHK3hHWURrM0ZRRkh6K1JSb0svV2xUb3JLb3plVVVMS0pK?= =?utf-8?B?L1dreVF1QWtrTCtqb01TWlRNQ2szR2EzRTRhR2dEenR6NXdaWEc1RWhJekho?= =?utf-8?B?bWlORmg3WHpHOURWRXpEMFp2L1ZmdGlhTmh0NDFsS2FSRE0zc1RFejBNL2VW?= =?utf-8?B?KzhNWnUyRzczRnl0QWxxdG83TzhnRkZQM0QxdlJ2N01ZY0lmSTVUVXJLSTJD?= =?utf-8?B?RTlZcFpQd1RVMzdEaEpSZFdKeEswNGJKSFFMVDVVTGhnTzArUm50QUczSVF6?= =?utf-8?B?b0FGVFJ5bXcyWGYvQWFjdzVtNVFPaFEyYm52NWlnbzYvYlFoUjkvWkgvMVlq?= =?utf-8?B?RzlzR1h4NmlLMWNiM2w5a04yL0hsUVVLaDNxTzg5Nk5KeDB5cm12V2JTamEx?= =?utf-8?B?NXpyYi9jbkYzbHBUbWtobjY2SngrWTBTREI4OXBRTkRmYnZZK3lvT0I2TVF0?= =?utf-8?B?Vks5SEZvb0toblkreXhqcnc5RlI4YzRiNkpoRFRVd1VOVktFSGszU3FGUXdD?= =?utf-8?B?ZEFuU05LU1RXcDE1RSt2L3JuVUdJTWg0SGVPYWlCUXR4UjFXWkwzcUpyYlhm?= =?utf-8?B?VitXaHh1OWNYcU9vRnBTaVRiNHVOL09lTmpUWDRickpIM0tzSE1SaDBhU3I1?= =?utf-8?B?STZjQ1pOOExhUHppa0M0ZFBrVHZTNFc0NGdialZ2MXVmK1F2N3BvWi8xV08z?= =?utf-8?B?QXc9PQ==?= X-OriginatorOrg: vaisala.com X-MS-Exchange-CrossTenant-Network-Message-Id: c57f02ea-6788-4c04-9534-08db81790f3d X-MS-Exchange-CrossTenant-AuthSource: HE1PR0602MB3241.eurprd06.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 10 Jul 2023 19:08:35.3120 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 6d7393e0-41f5-4c2e-9b12-4c2be5da5c57 X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: qOiETlkbkPPMtLHxOx3XaeOchjs4Ndx0OS6TMyha9AFXVl9st6VmtZdKODXaLPZhCpW6bE+Oe7vIXFKzCzjJpoDnl9reEruVLrsKGDadgW0= X-MS-Exchange-Transport-CrossTenantHeadersStamped: AS8PR06MB7958 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10.7.2023 21.38, Andrew Lunn wrote: > On Mon, Jul 10, 2023 at 08:56:18PM +0300, Vesa Jääskeläinen wrote: >> Add support to specify either class A or class B (default) for line driver. >> >> Class A: full MLT-3 on both Tx+ and Tx– >> Class B: reduced MLT-3 >> >> By default the PHY is in Class B mode. > Hi Vesa > > Do you have a reference to 802.3 or some other document which > describes these. How does reduced differ from full? Is this really a > hardware property of the board? > > Thanks > Andrew Hi Andrew, This is needed for configuration in link between DP83822 and Ethernet Switch chip. In the connection there there is no Ethernet cable at all but routes within the circuit boards but instead has capacitive coupling on routes. The other Ethernet port with the same phy is connected to normal Ethernet cable and in there this configuration is not needed. So the setting itself is related to specific circuit board design. MLT-3 is related to encoding used in the signals -- I suppose wiki page is good introduction reference: https://en.wikipedia.org/wiki/MLT-3_encoding I suppose this question in TI's forum gives indication what is the effect of the setting: https://e2e.ti.com/support/interface-group/interface/f/interface-forum/572998/dp83822hf-transformerless-operation TI's datasheet is not too verbose about the effect: https://www.ti.com/lit/ds/symlink/dp83822hf.pdf?ts=1688188848392&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FDP83822HF I cannot say I am expert on the Ethernet line encoding -- my understanding is that full MLT-3 is "normal" signaling mode and reduced MLT-3 mode is extension on the chip to perhaps reduce energy consumption with real Ethernet cables or something like that but in chip-to-chip link the reduced mode does not work and full MLT-3 is needed in order for link to come up. I hope this helps? Thanks, Vesa Jääskeläinen