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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY,USER_AGENT_SANE_1 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 A5683C4BA0B for ; Wed, 26 Feb 2020 09:24:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 808B22072D for ; Wed, 26 Feb 2020 09:24:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727520AbgBZJYM (ORCPT ); Wed, 26 Feb 2020 04:24:12 -0500 Received: from bhuna.collabora.co.uk ([46.235.227.227]:49712 "EHLO bhuna.collabora.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726541AbgBZJYM (ORCPT ); Wed, 26 Feb 2020 04:24:12 -0500 Received: from [127.0.0.1] (localhost [127.0.0.1]) (Authenticated sender: eballetbo) with ESMTPSA id 0209328DB54 Subject: Re: [PATCH v8 0/6] arm/arm64: mediatek: Fix mmsys device probing To: CK Hu Cc: mark.rutland@arm.com, Kate Stewart , Minghsiu Tsai , Andrew-CT Chen , airlied@linux.ie, mturquette@baylibre.com, dri-devel@lists.freedesktop.org, Richard Fontana , laurent.pinchart@ideasonboard.com, ulrich.hecht+renesas@gmail.com, Collabora Kernel ML , linux-clk@vger.kernel.org, Nicolas Boichat , Weiyi Lu , Krzysztof Kozlowski , wens@csie.org, Allison Randal , mtk01761 , Owen Chen , linux-media@vger.kernel.org, devicetree@vger.kernel.org, p.zabel@pengutronix.de, frank-w@public-files.de, Seiya Wang , sean.wang@mediatek.com, Houlong Wei , robh+dt@kernel.org, linux-mediatek@lists.infradead.org, hsinyi@chromium.org, Matthias Brugger <"matthias. bgg"@gmail.com>, Thomas Gleixner , Mauro Carvalho Chehab , linux-arm-kernel@lists.infradead.org, Matthias Brugger , Fabien Parent , sboyd@kernel.org, Greg Kroah-Hartman , rdunlap@infradead.org, linux-kernel@vger.kernel.org, Daniel Vetter , matthias.bgg@kernel.org References: <20200220172147.919996-1-enric.balletbo@collabora.com> <1582259996.1846.7.camel@mtksdaap41> <7a87b486-1622-7f27-f5af-427b94a14c00@collabora.com> <1582277229.25992.9.camel@mtksdaap41> <1393a8c5-065f-cccb-2563-8b159c951d4b@suse.com> <1582283518.5889.10.camel@mtksdaap41> <6deab0a4-44a6-a15f-ac01-374f818b267c@collabora.com> <6eb9da70-9a0c-27fc-6c31-3ac62ede5a35@suse.com> <1582523544.25316.2.camel@mtksdaap41> <688f6c85-0063-9458-858c-de7bbfb8a530@collabora.com> <1582695176.8324.4.camel@mtksdaap41> From: Enric Balletbo i Serra Message-ID: <6355f1fd-b929-730e-e0f6-96dd5100e3f9@collabora.com> Date: Wed, 26 Feb 2020 10:24:04 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.5.0 MIME-Version: 1.0 In-Reply-To: <1582695176.8324.4.camel@mtksdaap41> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: devicetree-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org Hi CK, On 26/2/20 6:32, CK Hu wrote: [snip] >> >> How do you see move mmsys to drivers/soc/mediatek and instantiate the clk and >> mediatek-drm driver >> >> mmsys: syscon@14000000 { >> compatible = "mediatek,mt8173-mmsys", "syscon", "simple-mfd"; >> reg = <0 0x14000000 0 0x1000>; >> power-domains = <&scpsys MT8173_POWER_DOMAIN_MM>; >> >> clock-controller { >> compatible = "mediatek,clk-mt8173-mm" >> assigned-clocks = <&topckgen CLK_TOP_MM_SEL>; >> assigned-clock-rates = <400000000>; >> #clock-cells = <1>; >> }; >> >> display-subsystem { >> compatible = "mediatek,display-subsystem"; >> }; >> }; >> > > Let's start with the simple definition. > > mmsys: syscon at 14000000 { > compatible = "mediatek,mt8173-mmsys", "syscon"; > reg = <0 0x14000000 0 0x1000>; > power-domains = <&scpsys MT8173_POWER_DOMAIN_MM>; > assigned-clocks = <&topckgen CLK_TOP_MM_SEL>; > assigned-clock-rates = <400000000>; > #clock-cells = <1>; > }; > > When we break clock control to a sub device of mmsys, the reason is that > 'Linux' generally categorize clock controller to a device. When we break > display control to a sub device of mmsys, the reason is that 'Linux' > generally categorize display controller to a device. All these seems > software-oriented reason, so I think we do not break any sub device and > keep mmsys simple. > > When I search of_clk_add_provider(), I find that not all clock provider > code is in drivers/clk. Maybe when a clock controller is not an > independent device, the driver code of clock controller could be placed > within the device driver it belonged to. We could place mmsys driver in > drivers/soc/mediatek/, and it control the clock, routing, fake engine, > memory delay,.... I would like drm driver to be placed in > drivers/gpu/drm/ because display function block, such as OVL, does not > belong to mmsys device. And finally let mmsys driver to probe > mediatek-drm driver. > You can apply the same reasoning in the clk subsystem, not all the drivers in drivers/clk are pure clock controllers, some of them are already system-controller or "simple-mfd" and some of them even instantiate other subdrivers via the platform register API. Note that moving clk--mm drivers to drivers/soc/mediatek will imply move a lot of code, I'll focus only on mt8173 for now because is the only platform I can really test. Let me prepare a v9 and lets see how looks like. Thanks, Enric > Regards, > CK [snip]