From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.0 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 75F27C2D0A7 for ; Fri, 4 Sep 2020 14:24:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4E132206B7 for ; Fri, 4 Sep 2020 14:24:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730774AbgIDOYy (ORCPT ); Fri, 4 Sep 2020 10:24:54 -0400 Received: from vps0.lunn.ch ([185.16.172.187]:43130 "EHLO vps0.lunn.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730483AbgIDOXx (ORCPT ); Fri, 4 Sep 2020 10:23:53 -0400 Received: from andrew by vps0.lunn.ch with local (Exim 4.94) (envelope-from ) id 1kECd1-00DCyV-9k; Fri, 04 Sep 2020 16:23:47 +0200 Date: Fri, 4 Sep 2020 16:23:47 +0200 From: Andrew Lunn To: Adam =?utf-8?Q?Rudzi=C5=84ski?= Cc: Florian Fainelli , netdev@vger.kernel.org, m.felsch@pengutronix.de, hkallweit1@gmail.com, richard.leitner@skidata.com, zhengdejin5@gmail.com, devicetree@vger.kernel.org, kernel@pengutronix.de, kuba@kernel.org, robh+dt@kernel.org Subject: Re: [PATCH net-next 0/3] net: phy: Support enabling clocks prior to bus probe Message-ID: <20200904142347.GP3112546@lunn.ch> References: <20200903043947.3272453-1-f.fainelli@gmail.com> <307b343b-2e8d-cb20-c22f-0e80acdf1dc9@arf.net.pl> <20200904134558.GL3112546@lunn.ch> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Fri, Sep 04, 2020 at 04:00:55PM +0200, Adam Rudziński wrote: > W dniu 2020-09-04 o 15:45, Andrew Lunn pisze: > > > Just a bunch of questions. > > > > > > Actually, why is it necessary to have a full MDIO bus scan already during > > > probing peripherals? > > That is the Linux bus model. It does not matter what sort of bus it > > is, PCI, USB, MDIO, etc. When the bus driver is loaded, the bus is > > enumerated and drivers probe for each device found on the bus. > > OK. But is it always expected to find all the devices on the bus in the > first run? Yes. Cold plug expects to find all the device while scanning the bus. > Does the bus model ever allow to just add any more devices? Kind of, > "hotplug". :) Hotplug is triggered by hardware saying a new device has been added/removed after cold plug. This is not a hotplug case. The hardware has not suddenly appeared, it has always been there. Andrew