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=-2.4 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,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 20E99C2BA19 for ; Wed, 15 Apr 2020 08:08:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DF766206F9 for ; Wed, 15 Apr 2020 08:08:36 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b="UeOoK6zh" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2635622AbgDOIIe (ORCPT ); Wed, 15 Apr 2020 04:08:34 -0400 Received: from perceval.ideasonboard.com ([213.167.242.64]:33816 "EHLO perceval.ideasonboard.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2635591AbgDOIIF (ORCPT ); Wed, 15 Apr 2020 04:08:05 -0400 Received: from [192.168.0.20] (cpc89242-aztw30-2-0-cust488.18-1.cable.virginm.net [86.31.129.233]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 9D67E2D1; Wed, 15 Apr 2020 10:07:58 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1586938079; bh=d3cM3Q3qHFbLBztwm4kDpHyKueuNUZD1Tu5L0584nsY=; h=Subject:To:Cc:References:Reply-To:From:Date:In-Reply-To:From; b=UeOoK6zhCEGPmWLfhjDbfahqvS6Qzqp2JDYPHFhNseng8pD8GWoA8LBLcfgqV8B0d FgdG8w1Y9HRgqoqn2TiLL/xE0BFME9xvY4VZWRmo4zLoJ2Z+SGoMKKSGLBNy4sGABS bcUJCRW8hGIv5gCmFr39QrbNGoYsl5bInOrGZepM= Subject: Re: [RFC PATCH v2 2/6] i2c: allow DT nodes without 'compatible' To: Wolfram Sang , Luca Ceresoli Cc: Wolfram Sang , linux-i2c@vger.kernel.org, linux-renesas-soc@vger.kernel.org, linux-i3c@lists.infradead.org, =?UTF-8?Q?Niklas_S=c3=b6derlund?= , Jacopo Mondi , Laurent Pinchart , Vladimir Zapolskiy , linux-kernel@vger.kernel.org, Geert Uytterhoeven , Rob Herring References: <20200318150059.21714-1-wsa+renesas@sang-engineering.com> <20200318150059.21714-3-wsa+renesas@sang-engineering.com> <11ca7487-ac07-f714-8573-20d1a0040212@lucaceresoli.net> <20200415075911.GA1141@ninjato> Reply-To: kieran.bingham+renesas@ideasonboard.com From: Kieran Bingham Organization: Ideas on Board Message-ID: <8937e466-fe3f-3686-98a9-8013990bc3f9@ideasonboard.com> Date: Wed, 15 Apr 2020 09:07:56 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.9.1 MIME-Version: 1.0 In-Reply-To: <20200415075911.GA1141@ninjato> Content-Type: text/plain; charset=windows-1252 Content-Language: en-GB Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Wolfram, On 15/04/2020 08:59, Wolfram Sang wrote: > >> As I said in the reply to v1, I think we should reserve addresses also >> when there is a compatible string but no matching driver, but this is >> another story and can be handled separately. > > Unless I misunderstand you, I think they do already. Note that > only 'i2cdetect' shows a device as busy *IFF* there is a driver bound to > it. The internal 'i2c_check_addr_busy' does not care about a driver > being bound. You can check this by trying to use > i2c_new_ancillary_device() with an address which is already described in > DT but which driver is disabled. Aha, is it easy enough to distinguish that difference in user-space so that we can present a specific character to indicate this in i2cdetect? Or is that not so easy? -- Kieran