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=-5.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_2 autolearn=no 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 B847AC5519F for ; Fri, 20 Nov 2020 14:19:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 78A972222A for ; Fri, 20 Nov 2020 14:19:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727766AbgKTOTB (ORCPT ); Fri, 20 Nov 2020 09:19:01 -0500 Received: from relay7-d.mail.gandi.net ([217.70.183.200]:36423 "EHLO relay7-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726172AbgKTOTB (ORCPT ); Fri, 20 Nov 2020 09:19:01 -0500 X-Originating-IP: 90.55.104.168 Received: from bootlin.com (atoulouse-258-1-33-168.w90-55.abo.wanadoo.fr [90.55.104.168]) (Authenticated sender: maxime.chevallier@bootlin.com) by relay7-d.mail.gandi.net (Postfix) with ESMTPSA id 21FF320007; Fri, 20 Nov 2020 14:18:55 +0000 (UTC) Date: Fri, 20 Nov 2020 15:18:52 +0100 From: Maxime Chevallier To: Andrew Lunn Cc: Russell King - ARM Linux admin , Tobias Waldekranz , Vivien Didelot , Florian Fainelli , Heiner Kallweit , "David S. Miller" , Antoine Tenart , Thomas Petazzoni , netdev@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: Re: net: phy: Dealing with 88e1543 dual-port mode Message-ID: <20201120151852.369f6d23@bootlin.com> In-Reply-To: <20201120135517.GH1804098@lunn.ch> References: <20201119152246.085514e1@bootlin.com> <20201119145500.GL1551@shell.armlinux.org.uk> <20201119162451.4c8d220d@bootlin.com> <87k0uh9dd0.fsf@waldekranz.com> <20201119231613.GN1551@shell.armlinux.org.uk> <87eekoanvj.fsf@waldekranz.com> <20201120103601.313a166b@bootlin.com> <20201120102538.GP1551@shell.armlinux.org.uk> <20201120135517.GH1804098@lunn.ch> X-Mailer: Claws Mail 3.17.5 (GTK+ 2.24.32; x86_64-redhat-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Hi Russell, Andrew, On Fri, 20 Nov 2020 14:55:17 +0100 Andrew Lunn wrote: >On Fri, Nov 20, 2020 at 10:25:38AM +0000, Russell King - ARM Linux admin wrote: >> On Fri, Nov 20, 2020 at 10:36:01AM +0100, Maxime Chevallier wrote: >> > So maybe we could be a bit more generic, with something along these lines : >> > >> > ethernet-phy@0 { >> > ... >> > >> > mdi { >> > port@0 { >> > media = "10baseT", "100baseT", "1000baseT"; >> > pairs = <1>; >> > }; >> > >> > port@1 { >> > media = "1000baseX", "10gbaseR" >> > }; >> > }; >> > }; >> >> Don't forget that TP requires a minimum of two pairs. > >Hi Russell > >Well, actually, there are automotive PHYs which use just one pair, so >called T1 PHYs. We have drivers for i think two so far, with one more >on the way. > >You also have to watch out for 'clever' PHYs. The Aquantia PHY can do >1000Base-T2, i.e. 1G over two pairs. This might be a proprietary >extension, rather than standardized, but it shows it can be done. So >you have to be careful about assumptions based on the number of pairs. You're right that the "pairs" property might not be needed, if we have an appropriate media string for each mode ( maybe "1000baseT1" and "1000baseT2" for the 2 modes you're referencing ? ). I can also see other use-cases where having an indication of the nature of the media interface we want to use for a PHY can be useful. If the overall idea of having such a representation of the mdi info is something that you can see being adopted, I'll work on a first draft implementation to see what this looks like. Thanks for you inputs ! Maxime