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=-0.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED 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 A449DC10DCE for ; Fri, 13 Mar 2020 08:54:19 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 7B9CE206FA for ; Fri, 13 Mar 2020 08:54:19 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="J46JfrqD" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7B9CE206FA Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=bootlin.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-i3c-bounces+linux-i3c=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=XnuGGI8KCEnKFNvMxah5Wt1Yfxu1EUuc1Ddk1ZzgxRw=; b=J46JfrqDlQRzB1 0iNxRFFg4z7dIWKmGghrlxIRk3U5OL6eYjc+uGra1bRfG2a2kAussLUm39+5HuTvpktUGebfkLuNd ihnxB4IWBxHDTaCBSfamyjUQCW4pFie6HUA/o97SL0ns2U7+uVL5cxjRnPDdwbpO7vybYenulKfWl bZJLe5FfLH9sraxA+zxDtUtLcy2FxkJi8CWgcQUmpKPaH85/ASMD7SpsxZJy1Lm0XMzv5jJsgXHX7 rVbyBT+FchJdoXTmZvO/t1E1e8fpIh8TxxIUJb7jP4DA9m1VXCl0BKaMuOZ3QiFNu0PRkyYHYJaeH cxDUjNIri6b1uQbkJbRA==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jCg5C-0003FC-Eb; Fri, 13 Mar 2020 08:54:18 +0000 Received: from relay1-d.mail.gandi.net ([217.70.183.193]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1jCMGa-0005uB-E9 for linux-i3c@lists.infradead.org; Thu, 12 Mar 2020 11:44:46 +0000 X-Originating-IP: 90.66.181.224 Received: from localhost (lfbn-lyo-1-2013-224.w90-66.abo.wanadoo.fr [90.66.181.224]) (Authenticated sender: alexandre.belloni@bootlin.com) by relay1-d.mail.gandi.net (Postfix) with ESMTPSA id 7A727240004; Thu, 12 Mar 2020 11:44:32 +0000 (UTC) Date: Thu, 12 Mar 2020 12:44:32 +0100 From: Alexandre Belloni To: Wolfram Sang Subject: Re: [RFC PATCH 3/7] i2c: allow DT nodes without 'compatible' Message-ID: <20200312114432.GA3384@piout.net> References: <20200220172403.26062-1-wsa+renesas@sang-engineering.com> <20200220172403.26062-4-wsa+renesas@sang-engineering.com> <20200312111950.GA1013@ninjato> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200312111950.GA1013@ninjato> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200312_044444_611758_0D275180 X-CRM114-Status: GOOD ( 18.34 ) X-Mailman-Approved-At: Fri, 13 Mar 2020 01:54:17 -0700 X-BeenThere: linux-i3c@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux I3C List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" , Kieran Bingham , Niklas =?iso-8859-1?Q?S=F6derlund?= , Linux Kernel Mailing List , Jacopo Mondi , Vladimir Zapolskiy , Linux-Renesas , Wolfram Sang , Geert Uytterhoeven , Linux I2C , Luca Ceresoli , linux-i3c@lists.infradead.org, Laurent Pinchart Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-i3c" Errors-To: linux-i3c-bounces+linux-i3c=archiver.kernel.org@lists.infradead.org On 12/03/2020 12:19:51+0100, Wolfram Sang wrote: > > Clearly this does not fit the case reported by Alexandre: a device > > having a driver which is known to be badly buggy, so we don't want to > > instantiate it. But again, this should not affect DT as it is not > > describing the HW, but only an implementation detail. Probably disabling > > or blacklisting the driver would be a better option there? > > "Fixing the driver" is the first thing coming to my mind ;) But yeah, > blacklisting would be another good solution. With only the information > above, DT is not the right place to fix a broken driver. > To be clear, the driver is working properly but the HW isn't. It is a PMIC and we need to avoid linux talking to it so the PMIC doesn't end up killing the bus. We end up with a node properly described in the device tree but with status = "disabled". The relevance to the discussion was that you know what is there and you want to avoid using its address. See the pmic node on i2c1 in arch/arm/boot/dts/at91-sama5d3_xplained.dts for what I'm referring to. > > My apologies to Wolfram, I appreciate a lot the effort you are doing, > > but before reviewing this patch I have never realized what I tried to > > explain above. > > All good, Luca! Talking over code usually brings in viewpoints which > have been missed so far. This is expected. Actually, I am very happy to > have this discussion! > > All the best, > > Wolfram > -- Alexandre Belloni, Bootlin Embedded Linux and Kernel engineering https://bootlin.com _______________________________________________ linux-i3c mailing list linux-i3c@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-i3c