From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Petazzoni Subject: Re: [RFC PATCH 1/3] of: provide a binding for the 'fixed-link' property Date: Mon, 12 Aug 2013 10:16:49 +0200 Message-ID: <20130812101649.743c08aa@skate> References: <1373902450-11857-1-git-send-email-thomas.petazzoni@free-electrons.com> <1373902450-11857-2-git-send-email-thomas.petazzoni@free-electrons.com> <20130812063806.GD2324@pengutronix.de> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: Grant Likely , Rob Herring , "David S. Miller" , Florian Fainelli , Lior Amsalem , netdev@vger.kernel.org, devicetree-discuss@lists.ozlabs.org, linux-arm-kernel@lists.infradead.org To: Sascha Hauer Return-path: Received: from top.free-electrons.com ([176.31.233.9]:52442 "EHLO mail.free-electrons.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1754180Ab3HLIRa (ORCPT ); Mon, 12 Aug 2013 04:17:30 -0400 In-Reply-To: <20130812063806.GD2324@pengutronix.de> Sender: netdev-owner@vger.kernel.org List-ID: Dear Sascha Hauer, On Mon, 12 Aug 2013 08:38:06 +0200, Sascha Hauer wrote: > > This patch adds: > > > > * A documentation for the Device Tree property "fixed-link". > > > > * A of_phy_register_fixed_link() OF helper, which provided an OF node > > that contains a "fixed-link" property, registers the corresponding > > fixed PHY. > > > > * Removes the warning on the of_phy_connect_fixed_link() that says > > new drivers should not use it, since Grant Likely indicated that > > this "fixed-link" property is indeed the way to go. > > > > Any progress with this series? I am not sure there really was a consensus yet on what the DT binding looks like. As soon as there is a consensus, I'm definitely willing to make progress on this series. > We have more and more boards here with exactly the same problem as > Thomas has. For reasons stated below I don't like this binding, but > still it would solve my problem. Ok. > > +Example: > > + > > +ethernet@0 { > > + ... > > + fixed-link = <1 1 1000 0 0>; > > + ... > > +}; > > I must say I don't like this binding at all for two reasons. As I explained, this binding was chosen for this RFC for two reasons: * It's the binding used on PowerPC platforms to represent fixed links. * It allows to encode all the informations into a single property, which avoids the need for a separate DT node for a "fake PHY", which isn't a representation of the hardware. > First the positional arguments make it impossible to add optional > arguments to the link. > > Second the other side of the link is most likely a switch. Once this > switch has its own node in the devicetree it seems like having a phandle > to the switch here would be better. So, in other words, what you're suggesting is something like: ethernet@0 { reg = <...>; interrupt = <...>; phy = <&phy0>; phy0: phy@0 { fixed-link; speed = <1000>; full-duplex; ... }; }; Or something else? Best regards, Thomas -- Thomas Petazzoni, Free Electrons Kernel, drivers, real-time and embedded Linux development, consulting, training and support. http://free-electrons.com