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 D117FEB8FB6 for ; Wed, 6 Sep 2023 11:02:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237140AbjIFLCD (ORCPT ); Wed, 6 Sep 2023 07:02:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42428 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236772AbjIFLCC (ORCPT ); Wed, 6 Sep 2023 07:02:02 -0400 Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [IPv6:2001:4b98:dc2:55:216:3eff:fef7:d647]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5688A1BB; Wed, 6 Sep 2023 04:01:48 -0700 (PDT) Received: from pendragon.ideasonboard.com (aztw-30-b2-v4wan-166917-cust845.vm26.cable.virginm.net [82.37.23.78]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 8E58610FC; Wed, 6 Sep 2023 13:00:19 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1693998019; bh=N42PrMhNFpBpVcotTxriEP2qoUFpOMZJHFS7+bFjaok=; h=In-Reply-To:References:Subject:From:Cc:To:Date:From; b=SbEUUI5pMyrnXwxJU2xkWGB3vQ9UYQV+etGxjYlcPOicAP8wxjjuhmJVpuAwShP0P insCddr5SyORhex+i/cBhj/ab6frUvXj32AYwauuM7NJD9lkKwYaQOROz3ipbOVZkq as2PDOk7YKPIXjBau6fIXyVdcaBAU4Ag979FcxfU= Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable In-Reply-To: <20230906093531.GO7971@pendragon.ideasonboard.com> References: <20230905233118.183140-1-paul.elder@ideasonboard.com> <20230905233118.183140-4-paul.elder@ideasonboard.com> <502fc7b1-a32d-6901-3a45-d2aa0e0c3849@linaro.org> <20230906083237.GL7971@pendragon.ideasonboard.com> <20230906090058.GB17308@pendragon.ideasonboard.com> <59e07c6a-6f1b-0cc7-dddc-96d2a4050843@linaro.org> <20230906093531.GO7971@pendragon.ideasonboard.com> Subject: Re: [PATCH 3/3] arm64: dts: mediatek: mt8365-pumpkin: Add overlays for thp7312 cameras From: Kieran Bingham Cc: Paul Elder , linux-media@vger.kernel.org, Mauro Carvalho Chehab , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Hans Verkuil , devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org To: Krzysztof Kozlowski , Laurent Pinchart Date: Wed, 06 Sep 2023 12:01:43 +0100 Message-ID: <169399810391.277971.691693692840899613@ping.linuxembedded.co.uk> User-Agent: alot/0.10 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Quoting Laurent Pinchart (2023-09-06 10:35:31) > On Wed, Sep 06, 2023 at 11:21:31AM +0200, Krzysztof Kozlowski wrote: > > On 06/09/2023 11:00, Laurent Pinchart wrote: > > >>> has a regulator@0. There are similar instances for clocks. > > >>> > > >>> I understand why it may not be a good idea, and how the root node is > > >>> indeed not a bus. In some cases, those regulators and clocks are gr= ouped > > >>> in a regulators or clocks node that has a "simple-bus" compatible. = I'm > > >>> not sure if that's a good idea, but at least it should validate. > > >>> > > >>> What's the best practice for discrete board-level clocks and regula= tors > > >>> in overlays ? How do we ensure that their node name will not confli= ct > > >>> with the board to which the overlay is attached ? > > >> > > >> Top-level nodes (so under /) do not have unit addresses. If they hav= e - > > >> it's an error, because it is not a bus. Also, unit address requires = reg. > > >> No reg? No unit address. DTC reports this as warnings as well. > > >=20 > > > I agree with all that, but what's the recommended practice to add > > > top-level clocks and regulators in overlays, in a way that avoids > > > namespace clashes with the base board ? > >=20 > > Whether you use regulator@0 or regulator-0, you have the same chances of > > clash. >=20 > No disagreement there. My question is whether there's a recommended > practice to avoid clashes, or if it's an unsolved problem that gets > ignored for now because there's only 36h in a day and there are more > urgent things to do. Should an overlay add these items to a simple-bus specific to that overlay/device that is being supported? That would 'namespace' the added fixed-clocks/fixed-regulators etc... But maybe it's overengineering or mis-using the simple-bus. And the items are still not on a 'bus' with an address - they just exist on a presumably externally provided board.... -- Kieran