From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from relay1-d.mail.gandi.net (relay1-d.mail.gandi.net [217.70.183.193]) (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 E887684FD1; Thu, 15 Feb 2024 10:41:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.70.183.193 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707993692; cv=none; b=FdvTqti5rcpNUDAOLyfBPddC/QOPKOnhYWrAeaBeHL/uUVH5+9iVIqyZ5p72yfSmjr0qjfdwFZ5LQPHsjdJtR4LeY/Yq0Q/HlUncIN+D6R+7tJPAhmbSjVYnwv5KEWaGY1ZCN7e88WJdxrAib04zuFkBef1jzYFebH9SvDiznMs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707993692; c=relaxed/simple; bh=eVKgJ+PdR5o6UVkgqUdQLFko+Czs5USvovgYmgBi2Dc=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=ELx3YrNVZRhiAHEnSuQrJUxWO/W55nEsUsNdGeQMM0HLLOBmA5Pq1E5V1HyZJHLo8GaJUDRzchDFjvgLPNxY9hRCaFzottKTk/UaVhJ8PS+CF7zsRzqDkXNj42Hi8GH9/J/7cs406KX5jj8m544KSqkiRzKA0FyHufiq+azEAac= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=bootlin.com; spf=pass smtp.mailfrom=bootlin.com; dkim=pass (2048-bit key) header.d=bootlin.com header.i=@bootlin.com header.b=g1hJ/Hwe; arc=none smtp.client-ip=217.70.183.193 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=bootlin.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=bootlin.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=bootlin.com header.i=@bootlin.com header.b="g1hJ/Hwe" Received: by mail.gandi.net (Postfix) with ESMTPSA id 282AA240011; Thu, 15 Feb 2024 10:41:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=gm1; t=1707993686; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=eVKgJ+PdR5o6UVkgqUdQLFko+Czs5USvovgYmgBi2Dc=; b=g1hJ/Hwe7l8CextjF6EYChrf3HeQbqFoxg96KtpO+dqy3f/NIh7H2IVvt7ciyU7AlWyiEM 9aydTbAdFrLGwKHwvMEsIN8Tonb5SIrmQd+Hk5sk8PNjJkN63tcsCFBdour9lG4okj0lIH 15l2A7F9/wmNIX17BR9cS/+BPoSGn4ug0Ef0+EfVUShLQuprbM6iSoreONOuj+D9suTYS+ p/a4Bj5r7eoq1AVfQktXq1llinvAsjKo0rDqTDKNKs/tdBcIwAfPFjBG9WDx6/WoFmBHsM GdBsjc9FfSx3XWdqMZVG0R+JXfeBwdCG3glQaqd2A+fbdOcCj9Vd8hsIFDK+GQ== Date: Thu, 15 Feb 2024 11:41:23 +0100 From: =?UTF-8?B?S8O2cnk=?= Maincent To: Oleksij Rempel 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: <20240215114123.128e7907@kmaincent-XPS-13-7390> In-Reply-To: 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> Organization: bootlin X-Mailer: Claws Mail 3.17.5 (GTK+ 2.24.32; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-GND-Sasl: kory.maincent@bootlin.com 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 > > > ---------------------------- > > >=20 > > > - **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 Interfac= e) > > > or MDI-X (Medium Dependent Interface Crossover) configuration. > > >=20 > > > - **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. =20 > >=20 > > Thanks for this documentation. > >=20 > > 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. =20 >=20 > @Kory, can you please update it. >=20 > > And what happens for 1000BaseT when all four pairs are in use? =20 >=20 > Hm.. good question. I didn't found the answer in the spec. By combining a= ll > 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-carr= ying" pairs for power transmission and Alternative B Delivers power over the "spa= re pairs"? On my understanding of the 2022 standard the definition is:=20 - 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. Regards, --=20 K=C3=B6ry Maincent, Bootlin Embedded Linux and kernel engineering https://bootlin.com