From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932455AbcEMU4U (ORCPT ); Fri, 13 May 2016 16:56:20 -0400 Received: from mail-lf0-f51.google.com ([209.85.215.51]:35969 "EHLO mail-lf0-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932426AbcEMU4R (ORCPT ); Fri, 13 May 2016 16:56:17 -0400 Subject: Re: [PATCH RFT 1/2] phylib: add device reset GPIO support To: Andrew Lunn References: <81129033.NXiOLTg1so@wasted.cogentembedded.com> <3641492.klKRrvS8tr@wasted.cogentembedded.com> <20160512184233.GJ30822@pengutronix.de> <5735995B.8030802@ti.com> <20160513204436.GC7600@lunn.ch> Cc: Roger Quadros , =?UTF-8?Q?Uwe_Kleine-K=c3=b6nig?= , grant.likely@linaro.org, robh+dt@kernel.org, devicetree@vger.kernel.org, f.fainelli@gmail.com, netdev@vger.kernel.org, frowand.list@gmail.com, pawel.moll@arm.com, mark.rutland@arm.com, ijc+devicetree@hellion.org.uk, galak@codeaurora.org, linux-kernel@vger.kernel.org, Linus Walleij From: Sergei Shtylyov Organization: Cogent Embedded Message-ID: <1a44a737-2b81-625b-8edf-d1c3dfcdd619@cogentembedded.com> Date: Fri, 13 May 2016 23:56:12 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.0 MIME-Version: 1.0 In-Reply-To: <20160513204436.GC7600@lunn.ch> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 05/13/2016 11:44 PM, Andrew Lunn wrote: >>> Another issue is that on some boards we have one reset line tied to >>> multiple PHYs.How do we prevent multiple resets being taking place when each of >>> the PHYs are registered? >> >> My patch just doesn't address this case -- it's about the >> individual resets only. > > This actually needs to be addresses a layer above. What you have is a > bus reset, not a device reset. No. There's simply no such thing as a bus reset for the xMII/MDIO busses, there's simply no reset signaling on them. Every device has its own reset signal and its own timing requirements. > So the gpio line is associated to the mdio bus, not a PHY. No. > Either your MDIO driver needs to handle the gpio > line, or in __mdio_register(), __mdiobus_register(), you mean? > before it starts looking at the > children. It's basically the same thing. The MDIO bus reset is a misconception. > > Andrew MBR, Sergei