Message-ID: <78e70cc9-a6ca-439b-bfca-3119299249de@arinc9.com>
Date: Sun, 24 Sep 2023 10:49:49 +0300
From: Arınç ÜNAL <arinc.unal@...nc9.com>
To: Andrew Lunn <andrew@...n.ch>
Cc: "Russell King (Oracle)" <linux@...linux.org.uk>,
 Rob Herring <robh+dt@...nel.org>,
 Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
 "David S. Miller" <davem@...emloft.net>, Eric Dumazet <edumazet@...gle.com>,
 Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>,
 Conor Dooley <conor+dt@...nel.org>,
 George McCollister <george.mccollister@...il.com>,
 Florian Fainelli <f.fainelli@...il.com>, Vladimir Oltean
 <olteanv@...il.com>, Kurt Kanzenbach <kurt@...utronix.de>,
 Matthias Brugger <matthias.bgg@...il.com>,
 AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>,
 Woojung Huh <woojung.huh@...rochip.com>, UNGLinuxDriver@...rochip.com,
 Linus Walleij <linus.walleij@...aro.org>,
 Alvin Šipraga <alsi@...g-olufsen.dk>,
 Clément Léger <clement.leger@...tlin.com>,
 Marcin Wojtas <mw@...ihalf.com>, Lars Povlsen <lars.povlsen@...rochip.com>,
 Steen Hegelund <Steen.Hegelund@...rochip.com>,
 Daniel Machon <daniel.machon@...rochip.com>,
 Radhey Shyam Pandey <radhey.shyam.pandey@....com>,
 Daniel Golle <daniel@...rotopia.org>, Landen Chao
 <Landen.Chao@...iatek.com>, DENG Qingfang <dqfext@...il.com>,
 Sean Wang <sean.wang@...iatek.com>,
 Geert Uytterhoeven <geert+renesas@...der.be>,
 Magnus Damm <magnus.damm@...il.com>,
 Maxime Chevallier <maxime.chevallier@...tlin.com>,
 Nicolas Ferre <nicolas.ferre@...rochip.com>,
 Claudiu Beznea <claudiu.beznea@...rochip.com>, Marek Vasut <marex@...x.de>,
 Claudiu Manoil <claudiu.manoil@....com>,
 Alexandre Belloni <alexandre.belloni@...tlin.com>,
 John Crispin <john@...ozen.org>, Madalin Bucur <madalin.bucur@....com>,
 Ioana Ciornei <ioana.ciornei@....com>, Lorenzo Bianconi
 <lorenzo@...nel.org>, Felix Fietkau <nbd@....name>,
 Horatiu Vultur <horatiu.vultur@...rochip.com>,
 Oleksij Rempel <linux@...pel-privat.de>,
 Alexandre Torgue <alexandre.torgue@...s.st.com>,
 Giuseppe Cavallaro <peppe.cavallaro@...com>,
 Jose Abreu <joabreu@...opsys.com>,
 Grygorii Strashko <grygorii.strashko@...com>, Sekhar Nori <nsekhar@...com>,
 Shyam Pandey <radhey.shyam.pandey@...inx.com>, mithat.guner@...ont.com,
 erkin.bozoglu@...ont.com, netdev@...r.kernel.org,
 devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
 linux-arm-kernel@...ts.infradead.org, linux-mediatek@...ts.infradead.org,
 linux-renesas-soc@...r.kernel.org
Subject: Re: [PATCH net-next v2 00/10] define and enforce phylink bindings

On 24/09/2023 06:15, Andrew Lunn wrote:
>>> There is a MAC driver currently under review which does not have a PHY
>>> at all. The MAC is directly connected to a switch, all within one
>>> IC. The link is always running at 5Gbps, the link is always up. It is
>>> physically impossible to connect a PHY, so get_link_settings just
>>> returns hard coded values.
>>
>> The fixed-link property would be used to describe the link of the MAC here.
> 
> Fixed-link make sense for a general purpose MAC which could be
> connected to a PHY, or could also be used without a PHY. fixed-link
> simplifies the code in that the MAC driver does not see a difference,
> it all looks like a PHY.
> 
> However for a MAC which cannot be connected to a PHY, there is no need
> to emulate a PHY. The MAC driver will be simpler. So i would not
> recommend a fixed-link in this situation.

There's a link, it must be described. The MAC driver can configure the link
without reading the fixed-link property as there's no room for guessing.

The phy-handle, pcs-handle, and sfp properties point out there's a PHY. The
fixed-link property can be used standalone to describe MAC to MAC links.

For this specific ethernet controller, the phy-handle, pcs-handle, and sfp
properties can be disallowed on its schema to point out the ethernet
controller cannot be connected to a PHY.

Arınç

Powered by blists - more mailing lists