From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753278AbcD1XOq (ORCPT ); Thu, 28 Apr 2016 19:14:46 -0400 Received: from mail-pa0-f52.google.com ([209.85.220.52]:34209 "EHLO mail-pa0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753045AbcD1XOn (ORCPT ); Thu, 28 Apr 2016 19:14:43 -0400 Subject: Re: [PATCH net-next] of: of_mdio: Check if MDIO bus controller is available To: Andrew Lunn References: <1461880510-27132-1-git-send-email-f.fainelli@gmail.com> <20160428221211.GE12753@lunn.ch> Cc: netdev@vger.kernel.org, davem@davemloft.net, nathan.sullivan@ni.com, nicolas.ferre@atmel.com, Rob Herring , Frank Rowand , Grant Likely , "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE" , open list From: Florian Fainelli Message-ID: <572298D2.3060809@gmail.com> Date: Thu, 28 Apr 2016 16:12:18 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.5.1 MIME-Version: 1.0 In-Reply-To: <20160428221211.GE12753@lunn.ch> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 28/04/16 15:12, Andrew Lunn wrote: > On Thu, Apr 28, 2016 at 02:55:10PM -0700, Florian Fainelli wrote: >> Add a check whether the 'struct device_node' pointer passed to >> of_mdiobus_register() is an available (aka enabled) node in the Device >> Tree. >> >> Rationale for doing this are cases where an Ethernet MAC provides a MDIO >> bus controller and node, and an additional Ethernet MAC might be >> connecting its PHY/switches to that first MDIO bus controller, while >> still embedding one internally which is therefore marked as "disabled". >> >> Instead of sprinkling checks like these in callers of >> of_mdiobus_register(), do this in a central location. > > I think this discussion has shown there is no documented best > practices for MDIO bus drivers and how PHYs nodes are placed within > device tree. Maybe you could document the generic MDIO binding, both > as integrated into a MAC device node, and as a separate device? Fair enough, I will submit something after re-spining this patch to use -ENODEV, which I agree is a better return code. Did you want me to remove that blurb from the commit message? -- Florian