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 301A3CCA47A for ; Wed, 22 Jun 2022 06:11:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1357084AbiFVGLF (ORCPT ); Wed, 22 Jun 2022 02:11:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56550 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230006AbiFVGLD (ORCPT ); Wed, 22 Jun 2022 02:11:03 -0400 Received: from mailgw01.mediatek.com (unknown [60.244.123.138]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EACC41F61C; Tue, 21 Jun 2022 23:11:00 -0700 (PDT) X-UUID: 5a727973065c4e8683ff43bae6390ba9-20220622 X-CID-P-RULE: Release_Ham X-CID-O-INFO: VERSION:1.1.6,REQID:b323eea3-5f11-4f5b-83c7-965cd29cae5c,OB:0,LO B:0,IP:0,URL:0,TC:0,Content:0,EDM:0,RT:0,SF:0,FILE:0,RULE:Release_Ham,ACTI ON:release,TS:0 X-CID-META: VersionHash:b14ad71,CLOUDID:8cf0b72d-1756-4fa3-be7f-474a6e4be921,C OID:IGNORED,Recheck:0,SF:nil,TC:nil,Content:0,EDM:-3,IP:nil,URL:1,File:nil ,QS:nil,BEC:nil,COL:0 X-UUID: 5a727973065c4e8683ff43bae6390ba9-20220622 Received: from mtkmbs11n1.mediatek.inc [(172.21.101.185)] by mailgw01.mediatek.com (envelope-from ) (Generic MTA with TLSv1.2 ECDHE-RSA-AES256-GCM-SHA384 256/256) with ESMTP id 514534466; Wed, 22 Jun 2022 14:10:56 +0800 Received: from mtkmbs11n2.mediatek.inc (172.21.101.187) by mtkmbs11n2.mediatek.inc (172.21.101.187) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.792.3; Wed, 22 Jun 2022 14:10:56 +0800 Received: from mhfsdcap04 (10.17.3.154) by mtkmbs11n2.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.2.792.3 via Frontend Transport; Wed, 22 Jun 2022 14:10:55 +0800 Message-ID: <2705069844be7b3152a810e21b9f737a88d0302d.camel@mediatek.com> Subject: Re: [PATCH 2/3] dt-bindings: usb: mtk-xhci: Allow middle optional clocks to be missing From: Wenbin Mei To: Chunfeng Yun , Krzysztof Kozlowski , "=?ISO-8859-1?Q?N=EDcolas?= F. R. A. Prado" CC: Greg Kroah-Hartman , Matthias Brugger , AngeloGioacchino Del Regno , , "Krzysztof Kozlowski" , Rob Herring , , , , , Date: Wed, 22 Jun 2022 14:10:55 +0800 In-Reply-To: References: <20220617222916.2435618-1-nfraprado@collabora.com> <20220617222916.2435618-3-nfraprado@collabora.com> <8639e64d-c659-7090-2d0a-078fd96cfbd4@linaro.org> <20220620155057.a6qilnhm7snzhapa@notapiano> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.28.5-0ubuntu0.18.04.2 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-MTK: N Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2022-06-22 at 09:57 +0800, Chunfeng Yun wrote: > On Tue, 2022-06-21 at 09:14 +0200, Krzysztof Kozlowski wrote: > > On 20/06/2022 17:50, Nícolas F. R. A. Prado wrote: > > > On Mon, Jun 20, 2022 at 10:50:57AM +0200, Krzysztof Kozlowski > > > wrote: > > > > On 20/06/2022 08:59, Chunfeng Yun wrote: > > > > > On Sun, 2022-06-19 at 14:05 +0200, Krzysztof Kozlowski wrote: > > > > > > On 19/06/2022 09:46, Chunfeng Yun wrote: > > > > > > > On Fri, 2022-06-17 at 18:25 -0700, Krzysztof Kozlowski > > > > > > > wrote: > > > > > > > > On 17/06/2022 15:29, Nícolas F. R. A. Prado wrote: > > > > > > > > > The current clock list in the binding doesn't allow > > > > > > > > > for > > > > > > > > > one of > > > > > > > > > the > > > > > > > > > optional clocks to be missing and a subsequent clock > > > > > > > > > to > > > > > > > > > be > > > > > > > > > present. > > > > > > > > > An > > > > > > > > > example where this is an issue is in mt8192.dtsi, > > > > > > > > > which > > > > > > > > > has > > > > > > > > > "sys_ck", > > > > > > > > > "ref_ck", "xhci_ck" and would cause dtbs_check > > > > > > > > > warnings. > > > > > > > > > > > > > > > > > > Change the clock list in a way that allows the middle > > > > > > > > > optional > > > > > > > > > clocks to > > > > > > > > > be missing, while still guaranteeing a fixed order. > > > > > > > > > The > > > > > > > > > "ref_ck" is > > > > > > > > > kept > > > > > > > > > as a const even though it is optional for simplicity, > > > > > > > > > since it > > > > > > > > > is > > > > > > > > > present in all current dts files. > > > > > > > > > > > > > > > > > > Signed-off-by: Nícolas F. R. A. Prado < > > > > > > > > > nfraprado@collabora.com> > > > > > > > > > --- > > > > > > > > > > > > > > > > > > .../devicetree/bindings/usb/mediatek,mtk- > > > > > > > > > xhci.yaml | 9 > > > > > > > > > +++++++-- > > > > > > > > > 1 file changed, 7 insertions(+), 2 deletions(-) > > > > > > > > > > > > > > > > > > diff --git > > > > > > > > > a/Documentation/devicetree/bindings/usb/mediatek,mtk- > > > > > > > > > xhci.yaml > > > > > > > > > b/Documentation/devicetree/bindings/usb/mediatek,mtk- > > > > > > > > > xhci.yaml > > > > > > > > > index 63cbc2b62d18..99a1b233ec90 100644 > > > > > > > > > --- > > > > > > > > > a/Documentation/devicetree/bindings/usb/mediatek,mtk- > > > > > > > > > xhci.yaml > > > > > > > > > +++ > > > > > > > > > b/Documentation/devicetree/bindings/usb/mediatek,mtk- > > > > > > > > > xhci.yaml > > > > > > > > > @@ -80,8 +80,13 @@ properties: > > > > > > > > > items: > > > > > > > > > - const: sys_ck # required, the following > > > > > > > > > ones > > > > > > > > > are > > > > > > > > > optional > > > > > > > > > - const: ref_ck > > > > > > > > > - - const: mcu_ck > > > > > > > > > - - const: dma_ck > > > > > > > > > + - enum: > > > > > > > > > + - mcu_ck > > > > > > > > > + - dma_ck > > > > > > > > > + - xhci_ck > > > > > > > > > + - enum: > > > > > > > > > + - dma_ck > > > > > > > > > + - xhci_ck > > > > > > > > > - const: xhci_ck > > > > > > > > > > > > > > > > You allow now almost any order here, including > > > > > > > > incorrect > > > > > > > > like > > > > > > > > sys,ref,xhci,xhci,xhci. > > > > > > > > > > > > > > > > The order of clocks has to be fixed and we cannot allow > > > > > > > > flexibility. > > > > > > > > Are > > > > > > > > you sure that these clocks are actually optional (not > > > > > > > > wired to > > > > > > > > the > > > > > > > > device)? > > > > > > > > > > > > > > In fact, these optional clocks are fixed, due to no gates > > > > > > > are > > > > > > > provided, > > > > > > > SW can't control them by CCF; > > > > > > > In this case, I usually use a fixed clock, or ignore it. > > > > > > > > > > > > But in some versions these clocks are controllable or not? > > > > > > > > > > Some SoCs are controllable, some ones are not (fixed clock). > > > > > > > > Thanks for confirming. Then I would prefer to make these clocks > > > > required > > > > (not optional) and always provide them - via common clock > > > > framework or > > > > fixed-clock. > > > > > > Hi Krzysztof and Chunfeng, > > > > > > thank you both for the feedback. > > > > > > Since the solution I proposed in this patch is not acceptable I > > > see > > > two options: > > > 1. Split the clocks in several if blocks matched by compatibles > > > 2. Make the clocks required and use fixed-clock nodes for the > > > missing clocks in > > > the DT > > > > > > My understanding is that 1 is the desirable solution if the clock > > > is really > > > missing in some hardware variants, while 2 is desirable if all > > > hardware variants > > > really receive all the clocks, only that on some variants they're > > > fixed and not > > > controlable by SW. > > > > > > From what I'm reading of this discussion it seems that the latter > > > is the case > > > here and thus we should go for 2. Is this correct? > > > > This is how I understood it as well, so correct from my side. > > Also right for me. > > > > > > > > > Also Chunfeng, do you have information on whether the same is > > > true > > > for the MMC > > > HW block? I recently submitted some changes to that binding [1] > > > but > > > I followed > > > approach 1 there instead. However if all the clocks are present > > > in > > > the HW level > > > there as well it would make more sense for me to change it to > > > follow approach 2. > > I discussed it with Wenbin, MMC seems a little different with USB, > > Hi Wenbin, > > Please give some comments about MMC, thanks > Hi Chunfeng, As we discussed, the following change is the desirable solution for the Mediatek MMC HW. https://lists.infradead.org/pipermail/linux-mediatek/2022-June/043691.html Thanks. > > > > > > Thanks, > > > Nícolas > > > > > > [1] > > > https://lore.kernel.org/all/20220617230114.2438875-1-nfraprado@collabora.com > > > > > > Best regards, > > Krzysztof > >