Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752392AbdF0IFk (ORCPT ); Tue, 27 Jun 2017 04:05:40 -0400 Received: from mail-wr0-f178.google.com ([209.85.128.178]:36328 "EHLO mail-wr0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751510AbdF0IFf (ORCPT ); Tue, 27 Jun 2017 04:05:35 -0400 Date: Tue, 27 Jun 2017 10:05:29 +0200 From: Corentin Labbe To: =?iso-8859-1?Q?Andr=E9?= Przywara Cc: robh+dt@kernel.org, mark.rutland@arm.com, maxime.ripard@free-electrons.com, wens@csie.org, linux@armlinux.org.uk, catalin.marinas@arm.com, will.deacon@arm.com, peppe.cavallaro@st.com, alexandre.torgue@st.com, devicetree@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-sunxi@googlegroups.com, linux-arm-kernel@lists.infradead.org, Icenowy Zheng Subject: Re: [PATCH v6 05/21] net-next: stmmac: Add dwmac-sun8i Message-ID: <20170627080529.GA2468@Red> References: <20170531071852.12422-1-clabbe.montjoie@gmail.com> <20170531071852.12422-6-clabbe.montjoie@gmail.com> <8e3d73a7-e9ff-d3e2-4bce-bcc79cdf86db@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <8e3d73a7-e9ff-d3e2-4bce-bcc79cdf86db@arm.com> User-Agent: Mutt/1.7.2 (2016-11-26) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2171 Lines: 51 On Mon, Jun 26, 2017 at 01:18:23AM +0100, Andr? Przywara wrote: > On 31/05/17 08:18, Corentin Labbe wrote: > > The dwmac-sun8i is a heavy hacked version of stmmac hardware by > > allwinner. > > In fact the only common part is the descriptor management and the first > > register function. > > Hi, > > I know I am a bit late with this, but while adapting the U-Boot driver > to the new binding I was wondering about the internal PHY detection: > > > So here you seem to deduce the usage of the internal PHY by the PHY > interface specified in the DT (MII = internal, RGMII = external). > I think I raised this question before, but isn't it perfectly legal for > a board to use MII with an external PHY even on those SoCs that feature > an internal PHY? > On the first glance that does not make too much sense, but apart from > not being the correct binding to describe all of the SoCs features I see > two scenarios: > 1) A board vendor might choose to not use the internal PHY because it > has bugs, lacks features (configurability) or has other issues. For > instance I have heard reports that the internal PHY makes the SoC go > rather hot, possibly limiting the CPU frequency. By using an external > MII PHY (which are still cheaper than RGMII PHYs) this can be avoided. > 2) A PHY does not necessarily need to be directly connected to > magnetics. Indeed quite some boards use (RG)MII to connect to a switch > IC or some other network circuitry, for instance fibre connectors. > > So I was wondering if we would need an explicit: > allwinner,use-internal-phy; > boolean DT property to signal the usage of the internal PHY? > Alternatively we could go with the negative version: > allwinner,disable-internal-phy; > > Or what about introducing a new "allwinner,internal-mii-phy" compatible > string for the *PHY* node and use that? > > I just want to avoid that we introduce a binding that causes us > headaches later. I think we can still fix this with a followup patch > before the driver and its binding hit a release kernel. > > Cheers, > Andre. > I just see some patch, where "phy-mode = internal" is valid. I will try to find a way to use it Regards