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=-1.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS 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 ABB06C43381 for ; Mon, 18 Mar 2019 12:46:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 72C7820811 for ; Mon, 18 Mar 2019 12:46:17 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=synopsys.com header.i=@synopsys.com header.b="GEuVKSBE" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727429AbfCRMqQ (ORCPT ); Mon, 18 Mar 2019 08:46:16 -0400 Received: from smtprelay4.synopsys.com ([198.182.47.9]:43688 "EHLO smtprelay.synopsys.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726704AbfCRMqP (ORCPT ); Mon, 18 Mar 2019 08:46:15 -0400 Received: from mailhost.synopsys.com (dc2-mailhost2.synopsys.com [10.12.135.162]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtprelay.synopsys.com (Postfix) with ESMTPS id 7A4E624E2DD1; Mon, 18 Mar 2019 05:46:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=synopsys.com; s=mail; t=1552913175; bh=/1tWVc5bZIXSiC0Pfe5YWqhw8dedYvs+49S2hCu8IXM=; h=Subject:To:CC:References:From:Date:In-Reply-To:From; b=GEuVKSBE8XWtK3Otr3DrJuAJSOkakOuF7uP/XuK4SjWNM8EtACHYhLZuJ5E7TNshb JsbKuCken5bA2lzLLwf6XoSuvQacTpGWbq2/Kts391V08Uzn7NYlKpwhUxbVhBkWnW JRrZkNFK3ZZOlPN+6wajgCgkBn0qkg0R7VsLOUtgxvp8KALMzKp2UojjAsj85LuLhD aRLiXv/nsHeuIL1eKZ3POjvN734eAHJAmwdwS9oBmTc8wF8/Wr8D0ESGpVqsmujsCH xmHlfnlOuCPEq5G+ub8P/8aIX1Yw5RlXkmmsjoV1+k/NLjTjxwcXDN0OEQlKOMcEq5 dkV70R4UEfOQw== Received: from US01WXQAHTC1.internal.synopsys.com (us01wxqahtc1.internal.synopsys.com [10.12.238.230]) (using TLSv1.2 with cipher AES128-SHA256 (128/128 bits)) (No client certificate requested) by mailhost.synopsys.com (Postfix) with ESMTPS id CA89AA0091; Mon, 18 Mar 2019 12:46:12 +0000 (UTC) Received: from DE02WEHTCB.internal.synopsys.com (10.225.19.94) by US01WXQAHTC1.internal.synopsys.com (10.12.238.230) with Microsoft SMTP Server (TLS) id 14.3.408.0; Mon, 18 Mar 2019 05:46:12 -0700 Received: from DE02WEHTCA.internal.synopsys.com (10.225.19.92) by DE02WEHTCB.internal.synopsys.com (10.225.19.94) with Microsoft SMTP Server (TLS) id 14.3.408.0; Mon, 18 Mar 2019 13:46:10 +0100 Received: from [10.107.19.176] (10.107.19.176) by DE02WEHTCA.internal.synopsys.com (10.225.19.80) with Microsoft SMTP Server (TLS) id 14.3.408.0; Mon, 18 Mar 2019 13:46:10 +0100 Subject: Re: [PATCH net] net: phy: Don't assume loopback is supported To: Andrew Lunn , Heiner Kallweit CC: Florian Fainelli , Jose Abreu , , , "David S. Miller" , Joao Pinto References: <19c8d2b3-bffe-b3b2-6e91-e878f89e5247@gmail.com> <20190317183843.GE22226@lunn.ch> From: Jose Abreu Message-ID: <07dd8427-4779-1706-3c0a-17ae58939c41@synopsys.com> Date: Mon, 18 Mar 2019 12:46:09 +0000 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.5.1 MIME-Version: 1.0 In-Reply-To: <20190317183843.GE22226@lunn.ch> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.107.19.176] Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Andrew and Heiner, On 3/17/2019 6:38 PM, Andrew Lunn wrote: > On Fri, Mar 15, 2019 at 03:48:41PM -0700, Florian Fainelli wrote: >> On 3/14/19 3:37 AM, Jose Abreu wrote: >>> Some PHYs may not support loopback mode so we need to check if register >>> is read-only. >>> >> >> In that case it may be appropriate to have a specific PHY driver that >> implements a set_loopback() method returning -EOPNOTSUPP instead of >> changing the generic PHY implementation. > > Hi Jose > > Since Heiner says this is a mandatory feature, we should not really > penalise conformant PHYs just because there is one broken PHY. We provide PHYs to our customers and in the documentation I have this can be an optional feature that HW team can choose to have or not, making the bit read-only or r/w. Heiner, can you please confirm there is no Clause 22 "pitfalls" / "hidden comments" that allow this bitfield to be read-only ? Thanks, Jose Miguel Abreu