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=-3.8 required=3.0 tests=BAYES_00, 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 32316C433DB for ; Wed, 10 Feb 2021 12:56:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DBBAC64E32 for ; Wed, 10 Feb 2021 12:56:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231255AbhBJMzv (ORCPT ); Wed, 10 Feb 2021 07:55:51 -0500 Received: from muru.com ([72.249.23.125]:59866 "EHLO muru.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229977AbhBJMzn (ORCPT ); Wed, 10 Feb 2021 07:55:43 -0500 Received: from atomide.com (localhost [127.0.0.1]) by muru.com (Postfix) with ESMTPS id 589B880EB; Wed, 10 Feb 2021 12:55:17 +0000 (UTC) Date: Wed, 10 Feb 2021 14:54:56 +0200 From: Tony Lindgren To: Daniel Palmer List-Id: Cc: Hector Martin , Arnd Bergmann , DTML , Marc Zyngier , Linux Kernel Mailing List , Krzysztof Kozlowski , SoC Team , Rob Herring , Olof Johansson , linux-arm-kernel , Stephen Boyd Subject: Re: [PATCH 18/18] arm64: apple: Add initial Mac Mini 2020 (M1) devicetree Message-ID: References: <20210204203951.52105-1-marcan@marcan.st> <20210204203951.52105-19-marcan@marcan.st> <20210208110441.25qc6yken4effd6c@kozik-lap> <4481998a-27f6-951e-bb4f-a9d2b95f211f@marcan.st> <4dd911d8-ce84-bf4d-3aae-95ef321b4a97@marcan.st> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Daniel Palmer [210210 12:24]: > Hi Hector, > > On Wed, 10 Feb 2021 at 20:49, Hector Martin wrote: > > > > Yeah, just don't use an imaginary dummy index for the reg. Use a real > > > register offset from a clock controller instance base, and a register > > > bit offset too if needed. > > > > I mean for fixed input clocks without any particular numbering, or for > > temporary fake clocks while we figure out the clock controller. Once a > > real clock controller is involved, if there are hardware indexes > > involved that are consistent then of course I'll use those in some way > > that makes sense. > > This exact problem exists for MStar/SigmaStar too. > As it stands there is no documentation to show what the actual clock > tree looks like so everything is guess and I need to come up with numbers. > I'm interested to see what the solution to this is as it will come up again > when mainlining chips without documentation. > > > > The purpose of the clock in this particular case is just to make the > > uart driver work, since it wants to know its reference clock; there is > > work to be done here to figure out the real clock tree > > FWIW arm/boot/dts/mstar-v7.dtsi has the same issue: Needs uart, > has no uart clock. In that instance the uart clock setup by u-boot > is passed to the uart driver as a property instead of creating a fake > clock. Using more local dts nodes for the fixed clocks might help a bit with the dummy numbering problem but is still not a nice solution. How about using node names like "clock-foo" for the fixed clocks? This would be along what we do for with regulator names. Rob and Stephen might have some better suggestions here. Regards, Tony