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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3E17AC54EBE for ; Mon, 16 Jan 2023 10:22:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230035AbjAPKWR (ORCPT ); Mon, 16 Jan 2023 05:22:17 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39010 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229446AbjAPKWM (ORCPT ); Mon, 16 Jan 2023 05:22:12 -0500 Received: from pandora.armlinux.org.uk (pandora.armlinux.org.uk [IPv6:2001:4d48:ad52:32c8:5054:ff:fe00:142]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 714441A943; Mon, 16 Jan 2023 02:22:09 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=armlinux.org.uk; s=pandora-2019; h=Sender:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=iKsbPmPOxLmnfubqPTJ5H1djw5UST5WyViZLMbpdVKo=; b=018EaVFyuOwt62sRzgWWnmFf3j dQ5EzGmQPrnj2doVCQdCX53P0hgvXrD59HW6dNtzk5TzYoNGH/4kDdlYFNwyEe4lqcGWXzsD+D192 gkWLEaEQueeuz1pJKnC8zt9ygskjdExEhp0IoQrfY7RDjXZdg0ZeyAx48xhtLKzTSWxRIem9t9rH6 vxNn1bLX4R5UkZ2JNR9qP+EW6zHZr2oq3n5ztpFN6pLufHwQIeooqVjb/NqOl/spLhwvthK1v7Bdn q2l/nWvHM1RZXT9blqw2nl+r0S6fCG0ODLVS8GKd78lPIC+Q7N7RlYRAyPNeszbpOvtgFcwcBqfpV BAucfrIQ==; Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:36118) by pandora.armlinux.org.uk with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1pHMcn-0004Yz-9q; Mon, 16 Jan 2023 10:21:56 +0000 Received: from linux by shell.armlinux.org.uk with local (Exim 4.94.2) (envelope-from ) id 1pHMcj-0005va-Fb; Mon, 16 Jan 2023 10:21:53 +0000 Date: Mon, 16 Jan 2023 10:21:53 +0000 From: "Russell King (Oracle)" To: Pierluigi Passaro Cc: Andrew Lunn , Pierluigi Passaro , Lars-Peter Clausen , "hkallweit1@gmail.com" , "davem@davemloft.net" , "edumazet@google.com" , "kuba@kernel.org" , "pabeni@redhat.com" , "netdev@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Eran Matityahu , Nate Drude , Francesco Ferraro Subject: Re: [PATCH] net: mdio: force deassert MDIO reset signal Message-ID: References: <20230115161006.16431-1-pierluigi.p@variscite.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: Russell King (Oracle) Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Mon, Jan 16, 2023 at 09:44:01AM +0000, Pierluigi Passaro wrote: > I can't really understand why the MDIO bus must check the PHY presence. > Other busses try the communication only while probing the slaves, > never before. That is not true. Any bus that relies on hardware identification to bind drivers reads the identifying information prior to probing. For example, PCI, USB, AMBA to name a few. AMBA didn't used to have this problem, but does now - but at least under AMBA there's a bit more standardisation to what needs to be done. With ethernet PHYs, what's needed is highly platform specific. -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!