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=-10.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=ham 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 D7276C388F7 for ; Wed, 28 Oct 2020 22:40:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7BCEC2076B for ; Wed, 28 Oct 2020 22:40:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1603924826; bh=XIEK/YlIEkhPPCZ0rUMBwvX3G7nZ6I4b2SL5W2aFfRQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=K7u7Y+YjUqQ45fXLKtaL7EUCa7HHSf6AaWhs3qdEyn1maNrq0YYsaYwgdDPpcaJhB tETp1eYEa0vM5dnZ15FTyUwwbJ0NjVSKVFn7GcIjTVtbJH1hfdZyGcq48OmvAn376C 2Qofa9kVa6Xfk8Ob0lLDzSo/WVyLJkWz1tDNsf+Y= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388022AbgJ1WkZ (ORCPT ); Wed, 28 Oct 2020 18:40:25 -0400 Received: from mail-ot1-f65.google.com ([209.85.210.65]:37475 "EHLO mail-ot1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388994AbgJ1Wjr (ORCPT ); Wed, 28 Oct 2020 18:39:47 -0400 Received: by mail-ot1-f65.google.com with SMTP id m22so659757ots.4; Wed, 28 Oct 2020 15:39:45 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:content-transfer-encoding :in-reply-to; bh=o6EwXQBfcMS/8hppO1O8Dg2kVJUq26B2UJyAmaDjbzk=; b=sRd22aRNw6zB6w/gluvROBwovTKpgYdsfCTCx/XJI8t+aLYXKHUchELoq+O5iqicEx B3lmmug5j/oQmHOgyR+4/EAJjkhmfhdIMsHp/6Qi3oLmGBh0ojWzA3YKviFFAP1a04v/ 7rcLJC8RsnISJzeCghZWLhB6iAzqprh88lNEBiTyxQ2chWIZJgVP/zpT1eeDuZ70wxVQ PtqDbYH8RcPaka8eqeLXYF2b5q6k6q/KDgAlJa7nG5dZClgq8jO33lxe7JJmwdRG3wnr A+t4Rfe1J9ufjzfYulrUN6Af1R28k+a4OKB8df/QWV20Bgjgov+LG6Y7+nZGdt9cPqOU P5+g== X-Gm-Message-State: AOAM533DGIIz9S5G7j0mqgcBQf66m5C+K1SShYVUAgq+UgoRMcEWrQj8 1GVLhzFl7nEc44X3mom8m36PEMobvw== X-Google-Smtp-Source: ABdhPJwj/TyDdKmqYTN4xYvs7B9zlCOZD1OUjrbHekbCo/ATjXWibtj5dLIGJwVVW7gCH9am8fXsDQ== X-Received: by 2002:a4a:ea4b:: with SMTP id j11mr6145795ooe.56.1603898585153; Wed, 28 Oct 2020 08:23:05 -0700 (PDT) Received: from xps15 (24-155-109-49.dyn.grandenetworks.net. [24.155.109.49]) by smtp.gmail.com with ESMTPSA id c20sm2076568otm.49.2020.10.28.08.23.03 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 28 Oct 2020 08:23:04 -0700 (PDT) Received: (nullmailer pid 4050074 invoked by uid 1000); Wed, 28 Oct 2020 15:23:03 -0000 Date: Wed, 28 Oct 2020 10:23:03 -0500 From: Rob Herring To: Krzysztof Kozlowski Cc: Dmitry Osipenko , Thierry Reding , Jonathan Hunter , Georgi Djakov , Michael Turquette , Stephen Boyd , Peter De Schrijver , MyungJoo Ham , Kyungmin Park , Chanwoo Choi , Mikko Perttunen , Viresh Kumar , Peter Geis , Nicolas Chauvet , linux-tegra@vger.kernel.org, linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, devicetree@vger.kernel.org Subject: Re: [PATCH v6 04/52] dt-bindings: memory: tegra20: emc: Document nvidia,memory-controller property Message-ID: <20201028152303.GA4041470@bogus> References: <20201025221735.3062-1-digetx@gmail.com> <20201025221735.3062-5-digetx@gmail.com> <20201027085417.GD4244@kozik-lap> <54191034-dcb9-7cab-333b-5bb2553f0ed1@gmail.com> <20201027193039.GA140636@kozik-lap> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20201027193039.GA140636@kozik-lap> Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org On Tue, Oct 27, 2020 at 08:30:39PM +0100, Krzysztof Kozlowski wrote: > On Tue, Oct 27, 2020 at 10:17:19PM +0300, Dmitry Osipenko wrote: > > 27.10.2020 11:54, Krzysztof Kozlowski пишет: > > > On Mon, Oct 26, 2020 at 01:16:47AM +0300, Dmitry Osipenko wrote: > > >> Tegra20 External Memory Controller talks to DRAM chips and it needs to be > > >> reprogrammed when memory frequency changes. Tegra Memory Controller sits > > >> behind EMC and these controllers are tightly coupled. This patch adds the > > >> new phandle property which allows to properly express connection of EMC > > >> and MC hardware in a device-tree, it also put the Tegra20 EMC binding on > > >> par with Tegra30+ EMC bindings, which is handy to have. > > >> > > >> Signed-off-by: Dmitry Osipenko > > >> --- > > >> .../bindings/memory-controllers/nvidia,tegra20-emc.txt | 2 ++ > > >> 1 file changed, 2 insertions(+) > > >> > > >> diff --git a/Documentation/devicetree/bindings/memory-controllers/nvidia,tegra20-emc.txt b/Documentation/devicetree/bindings/memory-controllers/nvidia,tegra20-emc.txt > > >> index 567cffd37f3f..1b0d4417aad8 100644 > > >> --- a/Documentation/devicetree/bindings/memory-controllers/nvidia,tegra20-emc.txt > > >> +++ b/Documentation/devicetree/bindings/memory-controllers/nvidia,tegra20-emc.txt > > >> @@ -12,6 +12,7 @@ Properties: > > >> irrespective of ram-code configuration. > > >> - interrupts : Should contain EMC General interrupt. > > >> - clocks : Should contain EMC clock. > > >> +- nvidia,memory-controller : Phandle of the Memory Controller node. > > > > > > It looks like you adding a required property which is an ABI break. > > The T20 EMC driver is unused so far in upstream and it will become used > > only once this series is applied. Hence it's fine to change the ABI. > > The ABI is not about upstream, but downstream. "If it's not upstream, it doesn't exist." Though we do have to account for out of tree users where the DT is not in tree, but upstream drivers are used. Downstream as in vendor kernels typically has loads of other crap. > There are no other > upstreams using this ABI. Unless you have in mind that existing T20 EMC > driver was a noop, doing absolutely nothing, therefore there is no > breakage of any other users? ABI breaks are ultimately up to the platform maintainers to decide. Rob