From mboxrd@z Thu Jan 1 00:00:00 1970 From: florian@openwrt.org (Florian Fainelli) Date: Tue, 22 Jan 2013 15:47:45 +0100 Subject: [PATCH] net: fec: Add support for multiple phys on mdiobus In-Reply-To: <50FE3E37.4010004@grandegger.com> References: <1358757475-21035-1-git-send-email-s.hauer@pengutronix.de> <50FD02B8.8080401@grandegger.com> <20130121100701.GX1906@pengutronix.de> <50FD2172.2020608@grandegger.com> <20130121120602.GZ1906@pengutronix.de> <50FE3E37.4010004@grandegger.com> Message-ID: <50FEA691.4050904@openwrt.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 01/22/2013 08:22 AM, Wolfgang Grandegger wrote: >> Well this could be done when the fixed phy driver could be registered >> with the devicetree, maybe like this: >> >> fixed-phy: mdiophy { >> compatible = "mdio-fixed-phy"; >> link = "100FD"; >> }; > > I find that confusing. There is *no* phy but just a fixed link to the > switch... > >> The good thing about this would be that every ethernet driver could just >> use such a fixed phy, any external mdio phy (like on Marvell Armada) or >> just a phy connected to the internal mdio interface provided by the ethernet >> core. > > What is wrong with the existing "fixed-link" property of the *ethernet* > node. The fixed-link handling should/could be done in the phy layer, and > not in the driver as it currently is implemented. Maybe that's the > reason why the current code is regarded as hack! As far as I have used it with the CPMAC driver, the fixed PHY is a specific PHY device and there is no specific handling to be done by the Ethernet MAC driver but eventually changing its MII bus id so that it is named "fixed-0" to allow the fixed PHY driver to bind. Put differently, using the fixed PHY driver is a kind of "last" resort thing to cope with situations like: - switch not providing a consistent PHY-like interface on the MDC/MDIO bus - switches not connected to the MDC/MDIO bus of the Ethernet MAC they forward to What exactly do you mean by "as it currently is implemented"? that you do not like? -- Florian From mboxrd@z Thu Jan 1 00:00:00 1970 From: Florian Fainelli Subject: Re: [PATCH] net: fec: Add support for multiple phys on mdiobus Date: Tue, 22 Jan 2013 15:47:45 +0100 Message-ID: <50FEA691.4050904@openwrt.org> References: <1358757475-21035-1-git-send-email-s.hauer@pengutronix.de> <50FD02B8.8080401@grandegger.com> <20130121100701.GX1906@pengutronix.de> <50FD2172.2020608@grandegger.com> <20130121120602.GZ1906@pengutronix.de> <50FE3E37.4010004@grandegger.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Cc: Sascha Hauer , netdev@vger.kernel.org, linux-arm-kernel@lists.infradead.org, shawn.guo@linaro.org, davem@davemloft.net To: Wolfgang Grandegger Return-path: Received: from mail-lb0-f173.google.com ([209.85.217.173]:34157 "EHLO mail-lb0-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752608Ab3AVOua (ORCPT ); Tue, 22 Jan 2013 09:50:30 -0500 Received: by mail-lb0-f173.google.com with SMTP id gf7so4502182lbb.32 for ; Tue, 22 Jan 2013 06:50:28 -0800 (PST) In-Reply-To: <50FE3E37.4010004@grandegger.com> Sender: netdev-owner@vger.kernel.org List-ID: On 01/22/2013 08:22 AM, Wolfgang Grandegger wrote: >> Well this could be done when the fixed phy driver could be registered >> with the devicetree, maybe like this: >> >> fixed-phy: mdiophy { >> compatible = "mdio-fixed-phy"; >> link = "100FD"; >> }; > > I find that confusing. There is *no* phy but just a fixed link to the > switch... > >> The good thing about this would be that every ethernet driver could just >> use such a fixed phy, any external mdio phy (like on Marvell Armada) or >> just a phy connected to the internal mdio interface provided by the ethernet >> core. > > What is wrong with the existing "fixed-link" property of the *ethernet* > node. The fixed-link handling should/could be done in the phy layer, and > not in the driver as it currently is implemented. Maybe that's the > reason why the current code is regarded as hack! As far as I have used it with the CPMAC driver, the fixed PHY is a specific PHY device and there is no specific handling to be done by the Ethernet MAC driver but eventually changing its MII bus id so that it is named "fixed-0" to allow the fixed PHY driver to bind. Put differently, using the fixed PHY driver is a kind of "last" resort thing to cope with situations like: - switch not providing a consistent PHY-like interface on the MDC/MDIO bus - switches not connected to the MDC/MDIO bus of the Ethernet MAC they forward to What exactly do you mean by "as it currently is implemented"? that you do not like? -- Florian