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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 10F0AC468A1 for ; Fri, 5 Jul 2019 16:39:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E472C21721 for ; Fri, 5 Jul 2019 16:39:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728557AbfGEQjk (ORCPT ); Fri, 5 Jul 2019 12:39:40 -0400 Received: from relay1-d.mail.gandi.net ([217.70.183.193]:54247 "EHLO relay1-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726302AbfGEQjj (ORCPT ); Fri, 5 Jul 2019 12:39:39 -0400 X-Originating-IP: 90.76.143.236 Received: from localhost (lfbn-1-2078-236.w90-76.abo.wanadoo.fr [90.76.143.236]) (Authenticated sender: antoine.tenart@bootlin.com) by relay1-d.mail.gandi.net (Postfix) with ESMTPSA id 37C4024000A; Fri, 5 Jul 2019 16:39:30 +0000 (UTC) Date: Fri, 5 Jul 2019 18:39:29 +0200 From: Antoine Tenart To: Andrew Lunn Cc: Antoine Tenart , davem@davemloft.net, richardcochran@gmail.com, alexandre.belloni@bootlin.com, UNGLinuxDriver@microchip.com, ralf@linux-mips.org, paul.burton@mips.com, jhogan@kernel.org, netdev@vger.kernel.org, linux-mips@vger.kernel.org, thomas.petazzoni@bootlin.com, allan.nielsen@microchip.com Subject: Re: [PATCH net-next 1/8] Documentation/bindings: net: ocelot: document the PTP bank Message-ID: <20190705163929.GK3926@kwain> References: <20190701100327.6425-1-antoine.tenart@bootlin.com> <20190701100327.6425-2-antoine.tenart@bootlin.com> <20190701135214.GD25795@lunn.ch> <20190705133016.GD3926@kwain> <20190705144517.GD4428@lunn.ch> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20190705144517.GD4428@lunn.ch> User-Agent: Mutt/1.12.0 (2019-05-25) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Hi Andrew, On Fri, Jul 05, 2019 at 04:45:17PM +0200, Andrew Lunn wrote: > On Fri, Jul 05, 2019 at 03:30:16PM +0200, Antoine Tenart wrote: > > > > I'm not sure about this: optional properties means some parts of the h/w > > can be missing or not wired. It's not the case here, it's "optional" in > > the driver only for dt compatibility (so that an older dt blob can work > > with a newer kernel image), but it's now mandatory in the binding. > > If the driver can work without it, it is clearly optional. You just > get reduced functionality. That is the thing with DT. You can never > add more required properties after the first commit without breaking > backwards compatibility. To make the documentation fit the driver, > somewhere you need to state they are optional. Either by placing the > new properties in the optional section of the binding, or add a > comment. The documentation is unrelated to the driver. It's the documentation of the binding itself, which is only describing the h/w. But I discussed this with a someone and I got to the same conclusion as your statement, because there can be old dt blobs in the wild and the binding documentation can be used to make new code. That code should be aware of required/optional properties. I'll fix this in v2. Thanks! Antoine -- Antoine Ténart, Bootlin Embedded Linux and Kernel engineering https://bootlin.com