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=-9.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 B7844C433DB for ; Wed, 24 Mar 2021 23:17:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8D74D61A14 for ; Wed, 24 Mar 2021 23:17:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231307AbhCXXQx (ORCPT ); Wed, 24 Mar 2021 19:16:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51718 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230261AbhCXXQp (ORCPT ); Wed, 24 Mar 2021 19:16:45 -0400 Received: from mail-pj1-x102d.google.com (mail-pj1-x102d.google.com [IPv6:2607:f8b0:4864:20::102d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 96B24C06174A; Wed, 24 Mar 2021 16:16:44 -0700 (PDT) Received: by mail-pj1-x102d.google.com with SMTP id w8so251647pjf.4; Wed, 24 Mar 2021 16:16:44 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=OtUEvkCJ2SPvQKrg37lPkJrHw8GNfzDTe5ABJYj7Lcc=; b=t9qDCIz4c29vPBrjl5t9XMJ6+sixb6Eg+AWdeVfIuFNWiMdkD4Gvwx0Sk7GW7d0fOy Gln4PXOkJdAJm9eTybshTVeOPXZmOc4ipwCj70XFRmi7jVqOl8uBQfPC03zTNXpzPSIV fe85ZkzacMLAzSmTmmdMnKrpiYBVMjh/r4i1gItwyKYOSV9rdLRimQa+GCyLxMd4u9/o CS5/e44rFGJUcpcNQRNCkOcx2sWYbQ42DwxF1hlwmPDJlQlc0ZGBl7j9kSTc9/b2hwf3 iYvn5XyJf6w02agjtYVsnXxQKeD95xQsvt4ohJL174r1xflUrMFgz6MZCCt1GrynE6Te tQBg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=OtUEvkCJ2SPvQKrg37lPkJrHw8GNfzDTe5ABJYj7Lcc=; b=LRRJIDy7LTGUQTYCsTWcpGVEg9Qzfvi5SeiYBroB4ZcMeXk+sxDOg1Ht6wUV7IRgu8 5nnBZbKjtQTIj0RepPSGa3k6dvzZ6mCkt3SBwj/hCi2USqP6V9J3Qk6Ko79492R5vhSt B9RpJBLn/OlnMpHAYmShqe4IglJXKXOCf4y6wEplkU71QXyAWb2KM+2TLgd1OryTU+pT PmjcZa1BKeFk/VwMxqKDWKe9Xzu5gdCaVp4aIAo5pHciadbfnbK4YJyXx+xvss5ustkH TG8hVfBKhkxqVNztb2aheV5sbsFY+HoFIDdfRFuBzCoAVyW/UsVEdeGv0vh4w8Cg0CoX V1LQ== X-Gm-Message-State: AOAM531emKgfq0NGoLJxlC+k2v7mCyOzhox0yjqYwRF9ZnuBFWi7oeMP ZdeB9IhU8dBK9Iwi7Rh3s/k= X-Google-Smtp-Source: ABdhPJy7ng7IOPTSu4cFwZuuTF8zgLanyHeejrkFI6R5h+8bDfJ5RFejtnBVumKIDBJz9rHR5X/Z9A== X-Received: by 2002:a17:90a:3be4:: with SMTP id e91mr5590803pjc.113.1616627803911; Wed, 24 Mar 2021 16:16:43 -0700 (PDT) Received: from [10.230.29.202] ([192.19.223.252]) by smtp.gmail.com with ESMTPSA id f20sm3573816pfa.10.2021.03.24.16.16.42 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 24 Mar 2021 16:16:43 -0700 (PDT) Subject: Re: [PATCH net-next 0/2] dt-bindings: define property describing supported ethernet PHY modes To: =?UTF-8?Q?Marek_Beh=c3=ban?= Cc: netdev@vger.kernel.org, Andrew Lunn , "David S . Miller" , Heiner Kallweit , Russell King , Rob Herring , devicetree@vger.kernel.org, pali@kernel.org References: <20210324103556.11338-1-kabel@kernel.org> <20210325000007.19a38bce@thinkpad> From: Florian Fainelli Message-ID: <755130b4-2fab-2b53-456f-e2304b1922f2@gmail.com> Date: Wed, 24 Mar 2021 16:16:41 -0700 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Firefox/78.0 Thunderbird/78.8.1 MIME-Version: 1.0 In-Reply-To: <20210325000007.19a38bce@thinkpad> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org On 3/24/2021 4:00 PM, Marek Behún wrote: > On Wed, 24 Mar 2021 14:19:28 -0700 > Florian Fainelli wrote: > >>> Another problem is that if lower modes are supported, we should >>> maybe use them in order to save power. >> >> That is an interesting proposal but if you want it to be truly valuable, >> does not that mean that an user ought to be able to switch between any >> of the supported PHY <=> MAC interfaces at runtime, and then within >> those interfaces to the speeds that yield the best power savings? > > If the code determines that there are multiple working configurations, > it theoretically could allow the user to switch between them. > > My idea was that this should be done by kernel, though. > > But power saving is not the main problem I am trying to solve. > What I am trying to solve is that if a board does not support all modes > supported by the MAC and PHY, because they are not wired or something, > we need to know about that so that we can select the correct mode for > PHYs that change this mode at runtime. OK so the runtime part comes from plugging in various SFP modules into a cage but other than that, for a "fixed" link such as a SFF or a soldered down PHY, do we agree that there would be no runtime changing of the 'phy-mode'? What I am trying to understand is why this needs to be added to the Device Tree as opposed to a bitmask within the PHY driver that indicates the various interface mode capabilities which, looking at the code you shared below, is how you make decisions ultimately. > >>> >>> But for this we need to know which phy-modes are supported on the >>> board. >>> >>> This series adds documentation for a new ethernet PHY property, >>> called `supported-mac-connection-types`. >> >> That naming does not quite make sense to me, if we want to describe the >> MAC supported connection types, then those would naturally be within the >> Ethernet MAC Device Tree node, no? If we are describing what the PHY is >> capable, then we should be dropping "mac" from the property name not to >> create confusion. > > I put "mac" there to indicate that this is the SerDes to the MAC (i.e. > host side in Marvell PHY). 88X3310 has another SerDes side (Fiber Side). > I guess I put "mac" there so that if in the future we wanted to specify > supported modes for the fiber side, we could add > `supported-fiber-connection-types`. You would traditionally find the words "line side" (copper, optical, etc.) and "MAC side" being used in datasheets, maybe you can use a similar naming here? > > But otherwise it does not matter where this property is. Rob Herring > says that maybe we don't need a new property at all. We can reuse > phy-mode property of the MAC, and enumerate all supported modes there. > >> >>> >>> When this property is present for a PHY node, only the phy-modes >>> listed in this property should be considered to be functional on >>> the board. >> >> Can you post the code that is going to utilize these properties so we >> have a clearer picture of how and what you need to solve? > > I am still working on this, so the repo may change, but look at > https://git.kernel.org/pub/scm/linux/kernel/git/kabel/linux.git/log/?h=phy-supported-interfaces > at the last three patches. > -- Florian