From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from metis.whiteo.stw.pengutronix.de (metis.whiteo.stw.pengutronix.de [185.203.201.7]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 629B212C53F for ; Thu, 15 Feb 2024 12:04:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.203.201.7 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707998671; cv=none; b=LY4ZtcEk2o36bxljpVNs07/lUZ7AFGvyHLjBpejEwCb7yGD3zZdPjavef1ltl85VxayJwkYIuvY1dcaxVykvbwz5Ovdx35LXfXPM7jAL1A8Pbhg+dWhGFBiYucnRZGXFdOGKSiYq04m9B8MoziCKU/dMERDW+KgPNcFTGj29BiA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707998671; c=relaxed/simple; bh=I+WHBDh5S+oGpcU8eKBicxfnW8AnEzmC7pw6JB4nYoI=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Y2zCUCr4lzVtkwzjDEAQvdXoJCFPbsyXQ+gB6J66PG6QqBzQT91XX3+9U6CvpWShbcLXT3F82HUdUBGpa+HBTBXYWMC6Vp8ug0lhQFAphd/ymhejSCybAsa/pObU6xdie9/1qhu3X/tNKESnTNRdBIbcI6dwriYWpVRgerzzWUM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=pengutronix.de; spf=pass smtp.mailfrom=pengutronix.de; arc=none smtp.client-ip=185.203.201.7 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=pengutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=pengutronix.de Received: from drehscheibe.grey.stw.pengutronix.de ([2a0a:edc0:0:c01:1d::a2]) by metis.whiteo.stw.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1raaTD-0000bP-Ha; Thu, 15 Feb 2024 13:04:03 +0100 Received: from [2a0a:edc0:2:b01:1d::c5] (helo=pty.whiteo.stw.pengutronix.de) by drehscheibe.grey.stw.pengutronix.de with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1raaTB-000sKl-Ua; Thu, 15 Feb 2024 13:04:01 +0100 Received: from ore by pty.whiteo.stw.pengutronix.de with local (Exim 4.96) (envelope-from ) id 1raaTB-00A1XF-2g; Thu, 15 Feb 2024 13:04:01 +0100 Date: Thu, 15 Feb 2024 13:04:01 +0100 From: Oleksij Rempel To: =?utf-8?B?S8O2cnk=?= Maincent Cc: Andrew Lunn , Rob Herring , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Jonathan Corbet , Luis Chamberlain , Russ Weight , Greg Kroah-Hartman , "Rafael J. Wysocki" , Krzysztof Kozlowski , Conor Dooley , Mark Brown , Frank Rowand , Heiner Kallweit , Russell King , Thomas Petazzoni , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, devicetree@vger.kernel.org, Dent Project Subject: Re: [PATCH net-next v3 14/17] dt-bindings: net: pse-pd: Add bindings for PD692x0 PSE controller Message-ID: References: <20240208-feature_poe-v3-0-531d2674469e@bootlin.com> <20240208-feature_poe-v3-14-531d2674469e@bootlin.com> <20240209145727.GA3702230-robh@kernel.org> <618be4b1-c52c-4b8f-8818-1e4150867cad@lunn.ch> <20240215114123.128e7907@kmaincent-XPS-13-7390> Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20240215114123.128e7907@kmaincent-XPS-13-7390> X-Sent-From: Pengutronix Hildesheim X-URL: http://www.pengutronix.de/ X-Accept-Language: de,en X-Accept-Content-Type: text/plain X-SA-Exim-Connect-IP: 2a0a:edc0:0:c01:1d::a2 X-SA-Exim-Mail-From: ore@pengutronix.de X-SA-Exim-Scanned: No (on metis.whiteo.stw.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: devicetree@vger.kernel.org On Thu, Feb 15, 2024 at 11:41:23AM +0100, Köry Maincent wrote: > On Thu, 15 Feb 2024 09:17:48 +0100 > Oleksij Rempel wrote: > > > On Wed, Feb 14, 2024 at 06:41:54PM +0100, Andrew Lunn wrote: > > > > Alternative A and B Overview > > > > ---------------------------- > > > > > > > > - **Alternative A:** Utilizes the data-carrying pairs for power > > > > transmission in 10/100BaseT networks. The power delivery's polarity in > > > > this alternative can vary based on the MDI (Medium Dependent Interface) > > > > or MDI-X (Medium Dependent Interface Crossover) configuration. > > > > > > > > - **Alternative B:** Delivers power over the spare pairs not used for > > > > data in 10/100BaseT networks. Unlike Alternative A, Alternative B's > > > > method separates power from data lines within the cable. Though it is > > > > less influenced by data transmission direction, Alternative B includes > > > > two configurations with different polarities, known as variant X and > > > > variant S, to accommodate different network requirements and device > > > > specifications. > > > > > > Thanks for this documentation. > > > > > > It might be worth pointing out that RJ-45 supports up to 4 > > > pairs. However, 10/100BaseT only makes use of two pairs for data > > > transfer from the four. 1000BaseT and above make use of all four pairs > > > for data transfer. If you don't know this, it is not so obvious what > > > 'data-carrying pairs' and 'spare pairs' mean. > > > > @Kory, can you please update it. > > > > > And what happens for 1000BaseT when all four pairs are in use? > > > > Hm.. good question. I didn't found the answer in the spec. By combining all ^^^^^^^^^^^^^^^^ > > puzzle parts I assume, different Alternative configurations are designed ^^^^^^^^^^^^^^^^^^^^^^ > > to handle conflict between "PSE Physical Layer classification" and PHY > > autoneg. > > Oleksij how did you get the definition of Alternative A uses the "data-carrying" > pairs for power transmission and Alternative B Delivers power over the "spare > pairs"? > > On my understanding of the 2022 standard the definition is: > - Alternative A is for pinout conductors 1, 2, 3 and 6 > - Alternative B is for pinout conductors 4, 5, 7, 8. > > Then indeed if we are in 10/100BaseT Alternative A are "data-carrying > pairs" and Alternative B are "spare pairs" but that's not the case on > 1000BaseT. > > You can see it in the figures in the paragraph 145.2.3. Please, re-read my answer :) Autoneg for 1000Mbit is not done on all 4 pairs. The only MDI/-X dependent transfer processes only on one pair is autoneg. Every thing else is extrapolated out of it. -- Pengutronix e.K. | | Steuerwalder Str. 21 | http://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |