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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id CB1B9C433F5 for ; Wed, 6 Apr 2022 08:53:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Date:CC:To:From:Subject:Message-ID:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=1t0aglFbMLupmctpnSbsDqFVDbkX4ud8A2FJ0SXcMew=; b=KGyaWH4nHvrnKN jjwoPHNIBrzP1P/k20oZoezLTXvGO95P/Pxoko/ExVz3agZGYd4/6DTXS9ebACt9fmvbILwUxDsIS xSOx2z9h5v5SjMnrLc7CXJa0WWOxiqZQXOpmv0FJO/pWr3inAKIK2PE3HerXO6USJkSeIQ2wwtWOy HRhdvJUC9eevxzhzyeZcWqNkQbFDszqUjGOiL/MSskl73eagmHOlNmNCR0VwTkAROT57UTYDtDV04 XmCkuxBeyQ0oy/Bkfm4zCMBymxZ9ACRgF7Y1zwUhr7bzY6VTiiTsr8RUXeQUHx/MiMFpNPxf+/xrg nVpHPMOpVohKZRXmCIfQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nc1P1-004pW9-1S; Wed, 06 Apr 2022 08:52:35 +0000 Received: from mailgw02.mediatek.com ([216.200.240.185]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1nc1Ou-004pUm-UY; Wed, 06 Apr 2022 08:52:32 +0000 X-UUID: a1d7fb92f3fd4724b96cc15c66b623ae-20220406 X-UUID: a1d7fb92f3fd4724b96cc15c66b623ae-20220406 Received: from mtkcas66.mediatek.inc [(172.29.193.44)] by mailgw02.mediatek.com (envelope-from ) (musrelay.mediatek.com ESMTP with TLSv1.2 ECDHE-RSA-AES256-SHA384 256/256) with ESMTP id 362904035; Wed, 06 Apr 2022 01:52:21 -0700 Received: from mtkmbs07n1.mediatek.inc (172.21.101.16) by MTKMBS62DR.mediatek.inc (172.29.94.18) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Wed, 6 Apr 2022 01:42:19 -0700 Received: from mtkcas10.mediatek.inc (172.21.101.39) by mtkmbs07n1.mediatek.inc (172.21.101.16) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Wed, 6 Apr 2022 16:42:18 +0800 Received: from mtksdccf07 (172.21.84.99) by mtkcas10.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.0.1497.2 via Frontend Transport; Wed, 6 Apr 2022 16:42:18 +0800 Message-ID: Subject: Re: [PATCH 1/4] dt-bindings: cpufreq: mediatek: transform cpufreq-mediatek into yaml From: Jia-Wei Chang To: Krzysztof Kozlowski , "Krzysztof Kozlowski" , "Rafael J . Wysocki" , Viresh Kumar , Rob Herring , Liam Girdwood , Mark Brown , Matthias Brugger CC: , , , , , , , , , , , Jia-Wei Chang Date: Wed, 6 Apr 2022 16:42:17 +0800 In-Reply-To: <56c5870e-bc41-39be-6b53-785396d8812b@linaro.org> References: <20220307122151.11666-1-jia-wei.chang@mediatek.com> <20220307122151.11666-2-jia-wei.chang@mediatek.com> <2cf526d400c011b5172ba4fc2c3f03b4a4f371dc.camel@mediatek.com> <96a823a2-f3b6-9fb7-c9d6-f1315f6056fd@kernel.org> <56c5870e-bc41-39be-6b53-785396d8812b@linaro.org> X-Mailer: Evolution 3.28.5-0ubuntu0.18.04.2 MIME-Version: 1.0 X-MTK: N X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220406_015229_044746_736FC850 X-CRM114-Status: GOOD ( 51.70 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Fri, 2022-04-01 at 18:32 +0200, Krzysztof Kozlowski wrote: > On 01/04/2022 15:26, Jia-Wei Chang wrote: > > On Thu, 2022-03-24 at 11:33 +0100, Krzysztof Kozlowski wrote: > > > On 24/03/2022 10:38, Jia-Wei Chang wrote: > > > > > > > > > > > > > > > > > diff --git > > > > > > a/Documentation/devicetree/bindings/cpufreq/cpufreq- > > > > > > mediatek.yaml > > > > > > b/Documentation/devicetree/bindings/cpufreq/cpufreq- > > > > > > mediatek.yaml > > > > > > new file mode 100644 > > > > > > index 000000000000..584946eb3790 > > > > > > --- /dev/null > > > > > > +++ b/Documentation/devicetree/bindings/cpufreq/cpufreq- > > > > > > mediatek.yaml > > > > > > @@ -0,0 +1,131 @@ > > > > > > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) > > > > > > +%YAML 1.2 > > > > > > +--- > > > > > > +$id: > > > > > > > > > > https://urldefense.com/v3/__http://devicetree.org/schemas/cpufreq/cpufreq-mediatek.yaml*__;Iw!!CTRNKA9wMg0ARbw!xbKG4TgD0MRpMLyGJVBZEGpZFrNOclrcxOCx_APKo5Nmg8nF2x5PcBdE0unvL2NdpChkMA$ > > > > > > > > > > > > +$schema: > > > > > > > > > > https://urldefense.com/v3/__http://devicetree.org/meta-schemas/core.yaml*__;Iw!!CTRNKA9wMg0ARbw!xbKG4TgD0MRpMLyGJVBZEGpZFrNOclrcxOCx_APKo5Nmg8nF2x5PcBdE0unvL2O8T_oxCQ$ > > > > > > > > > > > > + > > > > > > +title: Mediatek CPUFREQ driver Device Tree Bindings > > > > > > > > > > Please remove "driver Device Tree Bindings" because the title > > > > > should > > > > > describe the hardware. Therefore it could be something like > > > > > "Mediatek > > > > > SoC CPU frequency and voltage scaling". > > > > > > > > Thanks for your suggestion of title. > > > > Or should I use the origin title "Binding for MediaTek's > > > > CPUFreq > > > > driver"? > > > > > > Mediatek CPUFREQ > > > or > > > Mediatek CPU frequency scaling > > > > Ok, I will choose one of it. > > > > > > > > > > > > > > > > > > > How is it related to cpufreq-mediatek-hw.yaml? The > > > > > names/title > > > > > look > > > > > unfortunately too similar. > > > > > > > > No, mediatek-cpufreq is performing in kernel driver rather than > > > > on > > > > hardware. > > > > On the other hand, mediatek-cpufreq-hw is performing on > > > > hardware. > > > > That's why "hw" is present in its name. > > > > > > Unfortunately, I do not get it. The bindings are only about > > > hardware, > > > so > > > how bindings could be about CPU frequency scaling not in > > > hardware? > > > > Sorry, let me correct my statements. > > > > For mediatek-cpufreq here, the required hardware are clock and > > regulator which have to be under control of mediatek-cpufreq. > > That's > > the reason why it needs bindings. > > > > mediatek-cpufreq scales up and down voltage and frequency via > > kernel > > framework of clock and regulator, however, mediatek-cpufreq-hw > > delegate > > the voltage and frequency control to a hardware agent instead. > > OK, that makes sense, thanks for explanation. > > > > > > > > > > > > > > > > > > > > In general this does not look like proper bindings (see also > > > > > below > > > > > lack > > > > > of compatible). Bindings describe the hardware, so what is > > > > > exactly > > > > > the > > > > > hardware here? > > > > > > > > Except for SoC, there's no requirement of hardware binding for > > > > mediatek-cpufreq. > > > > mediatek-cpufreq recognizes the compatible of Mediatek SoC > > > > while > > > > probing. > > > > > > What is the hardware here? If there is no requirement for > > > bindings > > > for > > > mediate-cpufreq, why do we have this patch here? > > > > Sorry, that's my mistake. > > Clock and regulator are required hardware for mediatek-cpufreq. > > > > > > > > > > > > > > > > > > > > + > > > > > > +maintainers: > > > > > > + - Jia-Wei Chang > > > > > > + > > > > > > +description: | > > > > > > + CPUFREQ is used for scaling clock frequency of CPUs. > > > > > > + The module cooperates with CCI DEVFREQ to manage > > > > > > frequency > > > > > > for > > > > > > some Mediatek > > > > > > + SoCs. > > > > > > + > > > > > > +properties: > > > > > > > > > > How is this schema going to be applied? I don't see here > > > > > select > > > > > neither > > > > > compatible. > > > > > > > > As mentioned above, only compatible of SoC is required for > > > > mediatek- > > > > cpufreq. > > > > > > It does not answer my questions. How the schema is going to be > > > applied? > > > > Currently, we do use compatible of SoC to probe mediatek-cpufreq. > > Probing and binding to compatible is correct, but there is no > compatible > here, so the schema is a no-op. Does nothing. Correct. I will update it in the next version. > > > If the better way is using clock and regulator opp, do you have a > > suggestion to approach that? > > I mean I can't find a good example from other vendors trying to do > > that > > way. Or maybe I miss something? > > One other way (proper) is to use cpufreq-dt and existing bindings. I > understand that maybe you need some specific bindings here, but I > fail > to see how they would work. IOW, you don't have the compatible, no > select, so nothing can use these bindings. Also bindings do not refer > to > any specific hardware, like SoC model. > > It's good that you try to convert existing bindings to DT schema, but > with that they should be probably fixed/updated to match proper > bindings. I got it. I will add compatible information to property of bindings and dts example here as well. Should I split the overall change of yaml into two patches? One for conversion of bindings and the other for the rest of change. > > Best regards, > Krzysztof _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel