From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtpout-03.galae.net (smtpout-03.galae.net [185.246.85.4]) (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 4FE69258CDC; Wed, 26 Nov 2025 14:25:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.246.85.4 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764167117; cv=none; b=qdPbgONKLIaWrNheJZCDBmNsrhbTbL0q9S/tibwoQ33GAtuZMvl7EMPNEm4fPE+O6mCGGwT/iPNLXgPLugVOVPAksORfjZGWqD8CSR/pQAhxl4z3nb1ByBQYZ8bnKrDpKmHcR96sKUnyGlzx1L4/YFEM0TpEQg4YN+gEOwxyj8M= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764167117; c=relaxed/simple; bh=Ocfwjie9+FicOOaIBzOuGpVUjaUpRkYlK9kIutmZR7o=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=OU8Hzxd8T9cEWpEQwnFKjE9ny1Ng6Nx1D53nXPkoSp9YZAOBrQLePSwIhcXQ9nNa9ABFShH69AlYJVqYkMaxc9iE4Ye8k1i+ivAMgc0kjjAZerHGGNY9hC7FlJE7VDQH6iZPlsh3AjCXHREKU/YTHUMvX+OJPcT56ya0YdD75DQ= 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=k0ooTJYI; arc=none smtp.client-ip=185.246.85.4 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="k0ooTJYI" Received: from smtpout-01.galae.net (smtpout-01.galae.net [212.83.139.233]) by smtpout-03.galae.net (Postfix) with ESMTPS id 8725A4E418F3; Wed, 26 Nov 2025 14:25:12 +0000 (UTC) Received: from mail.galae.net (mail.galae.net [212.83.136.155]) by smtpout-01.galae.net (Postfix) with ESMTPS id 578AB60721; Wed, 26 Nov 2025 14:25:12 +0000 (UTC) Received: from [127.0.0.1] (localhost [127.0.0.1]) by localhost (Mailerdaemon) with ESMTPSA id 64B5A102F08EF; Wed, 26 Nov 2025 15:25:01 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=dkim; t=1764167111; h=from:subject:date:message-id:to:cc:mime-version:content-type: content-transfer-encoding:content-language:in-reply-to:references; bh=Sbs0A8qAYuq+r/+1fjxriavvnUhEfhMgY7SBF5X8V08=; b=k0ooTJYIYW0FYBMVhrgVBpA7A6kXMyqERAgQSrzwOurSlWfmkbqR/cAmccU11VWLC5YJEI n6WrPplsAi0/qCeWTP5rC5r6OVtJarSahnvu8/ytGNtL2IhjV2o4qcZLK1BKZ9REOhbIne GpHwbaHF7/xV6QP11Em8OqvJQxr/vpKrq/B/xhMU6iRCotsKbsvezuDAlSdbcWdLA7WkHY PgHtTABkVp75O1gL9djdWOv4/kvWgJGTXQQtoWevSW4VHF0gnednfaSxWzHACT5hKJnynF DcFAau2f9LPmwhjE9ZTrqGuSx7982EfRtb9Sv1Y9Gy4TO0KRoTFUYh71zTNEkA== Message-ID: <9c2518d8-a0ea-46ba-9069-999c2574cd24@bootlin.com> Date: Wed, 26 Nov 2025 15:25:00 +0100 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH net-next 1/9] dt-bindings: phy: rename transmit-amplitude.yaml to phy-common-props.yaml To: Vladimir Oltean , Andrew Lunn Cc: netdev@vger.kernel.org, devicetree@vger.kernel.org, linux-phy@lists.infradead.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org, Daniel Golle , Horatiu Vultur , Heiner Kallweit , Russell King , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Vinod Koul , Kishon Vijay Abraham I , Matthias Brugger , AngeloGioacchino Del Regno , Eric Woudstra , =?UTF-8?B?TWFyZWsgQmVo4oia4oirbg==?= , Lee Jones , Patrice Chotard , Holger Brunck References: <20251122193341.332324-1-vladimir.oltean@nxp.com> <20251122193341.332324-2-vladimir.oltean@nxp.com> <0faccdb7-0934-4543-9b7f-a655a632fa86@lunn.ch> <20251125214450.qeljlyt3d27zclfr@skbuf> <20251126072638.wqwbhhab3afxvm7x@skbuf> From: Maxime Chevallier Content-Language: en-US In-Reply-To: <20251126072638.wqwbhhab3afxvm7x@skbuf> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Last-TLS-Session-Version: TLSv1.3 Hi, On 26/11/2025 08:26, Vladimir Oltean wrote: > +Maxime, Holger > thread at https://lore.kernel.org/netdev/20251122193341.332324-2-vladimir.oltean@nxp.com/ > > On Tue, Nov 25, 2025 at 11:33:09PM +0100, Andrew Lunn wrote: >>> Yeah, although as things currently stand, I'd say that is the lesser of >>> problems. The only user (mv88e6xxx) does something strange: it says it >>> wants to configure the TX amplitude of SerDes ports, but instead follows >>> the phy-handle and applies the amplitude specified in that node. >>> >>> I tried to mentally follow how things would work in 2 cases: >>> 1. PHY referenced by phy-handle is internal, then by definition it's not >>> a SerDes port. >>> 2. PHY referenced by phy-handle is external, then the mv88e6xxx driver >>> looks at what is essentially a device tree description of the PHY's >>> TX, and applies that as a mirror image to the local SerDes' TX. >>> >>> I think the logic is used in mv88e6xxx through case #2, i.e. we >>> externalize the mv88e6xxx SerDes electrical properties to an unrelated >>> OF node, the connected Ethernet PHY. >> >> My understanding of the code is the same, #2. Although i would >> probably not say it is an unrelated node. I expect the PHY is on the >> other end of the SERDES link which is having the TX amplitudes >> set. This clearly will not work if there is an SFP cage on the other >> end, but it does for an SGMII PHY. > > It is unrelated in the sense that the SGMII PHY is a different kernel > object, and the mv88e6xxx is polluting its OF node with properties which > it then interprets as its own, when the PHY driver may have wanted to > configure its SGMII TX amplitude too, via those same generic properties. > >> I guess this code is from before the time Russell converted the >> mv88e6xxx SERDES code into PCS drivers. The register being set is >> within the PCS register set. The mv88e6xxx also does not make use of >> generic phys to represent the SERDES part of the PCS. So there is no >> phys phandle to follow since there is no phy. > > In my view, the phy-common-props.yaml are supposed to be applicable to either: > (1) a network PHY with SerDes host-side connection (I suppose the media > side electrical properties would be covered by Maxime's phy_port > work - Maxime, please confirm). True, but we could definitely conceive applying phy-common-props.yaml on the media-side as well :) I don't have a use-case for it right now though, and we don't yet have detailed descriptions of the electrical properties. Maxime