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=-2.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,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 17302C43387 for ; Fri, 28 Dec 2018 22:28:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D8ED021874 for ; Fri, 28 Dec 2018 22:28:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1546036136; bh=1kcgDHXoWwOcoEu59RAjMuWloNe4Hvrfo/HlcHMda7Q=; h=To:References:Subject:Cc:From:In-Reply-To:Date:List-ID:From; b=RMQmZs5XuU+qnnm3dmPKHCmNFc073J+9Z2pTB/leYuNzNDwceiwbbu1xHvvxm28HO DAd+H99Zqr+DZmv5DClQE9ikhu8nNkEDajSCof1xskwG2lSvaKJN5AdUTvhuDFKmMI RCOQ5NL5CI8IEgMFdV3gfbflagZhTKKCYNQxHyVU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726144AbeL1W24 (ORCPT ); Fri, 28 Dec 2018 17:28:56 -0500 Received: from mail.kernel.org ([198.145.29.99]:46004 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726083AbeL1W24 (ORCPT ); Fri, 28 Dec 2018 17:28:56 -0500 Received: from localhost (unknown [104.132.0.74]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 15514206C0; Fri, 28 Dec 2018 22:28:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1546036135; bh=1kcgDHXoWwOcoEu59RAjMuWloNe4Hvrfo/HlcHMda7Q=; h=To:References:Subject:Cc:From:In-Reply-To:Date:From; b=QZq+/ehyWBGnP/IjA1vgv9Vam7EthRGHfk/tw7xoJBAIc8sGQP5hcMRsBt3cto4Qo LCAFa5PuoeDx8eXcIY/XMvTfGeE+bAKHJUeQcAyAeLCKuuqo/rD/Vgc1wMP1IOmZq8 /8OcZbqf+DMI23wRyHE9VssoxO7kL831zchD8MHs= Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable To: Jorge Ramirez , Niklas Cassel Message-ID: <154603613437.179992.1170701312259011363@swboyd.mtv.corp.google.com> References: <1545039990-19984-1-git-send-email-jorge.ramirez-ortiz@linaro.org> <1545039990-19984-6-git-send-email-jorge.ramirez-ortiz@linaro.org> <154508986359.19322.1555129141976726505@swboyd.mtv.corp.google.com> <20181218143503.GA32562@centauri.ideon.se> <72bc192f-b60a-1209-7818-78a2fed07831@linaro.org> Subject: Re: [PATCH 05/13] clk: qcom: apcs-msm8916: get parent clock names from DT Cc: andy.gross@linaro.org, david.brown@linaro.org, jassisinghbrar@gmail.com, mark.rutland@arm.com, mturquette@baylibre.com, robh+dt@kernel.org, will.deacon@arm.com, bjorn.andersson@linaro.org, vkoul@kernel.org, sibis@codeaurora.org, georgi.djakov@linaro.org, arnd@arndb.de, horms+renesas@verge.net.au, heiko@sntech.de, enric.balletbo@collabora.com, jagan@amarulasolutions.com, olof@lixom.net, amit.kucheria@linaro.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-clk@vger.kernel.org From: Stephen Boyd User-Agent: alot/0.8 In-Reply-To: <72bc192f-b60a-1209-7818-78a2fed07831@linaro.org> Date: Fri, 28 Dec 2018 14:28:54 -0800 Sender: linux-clk-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-clk@vger.kernel.org Quoting Jorge Ramirez (2018-12-26 01:20:07) > On 12/18/18 15:35, Niklas Cassel wrote: > > On Mon, Dec 17, 2018 at 03:37:43PM -0800, Stephen Boyd wrote: > >> Quoting Jorge Ramirez-Ortiz (2018-12-17 01:46:22) > >>> Allow accessing the parent clock names required for the driver > >>> operation by using the device tree node. > >>> > >>> This permits extending the driver to other platforms without having to > >>> modify its source code. > >>> > >>> For backwards compatibility leave previous values as default. > >> > >> Why do we need to maintain backwards compatibility? Isn't is required > >> that the nodes have clocks properties? > >> > >=20 > > Hello Stephen, > >=20 > >=20 > > This is the existing DT nodes for msm8916: > >=20 > > a53pll: clock@b016000 { > > compatible =3D "qcom,msm8916-a53pll"; > > reg =3D <0xb016000 0x40>; > > #clock-cells =3D <0>; > > }; > >=20 > > apcs: mailbox@b011000 { > > compatible =3D "qcom,msm8916-apcs-kpss-global"= , "syscon"; > > reg =3D <0xb011000 0x1000>; > > #mbox-cells =3D <1>; > > clocks =3D <&a53pll>; > > #clock-cells =3D <0>; > > }; > >=20 > >=20 > > This is the (suggested) DT nodes for qcs404: > >=20 > > apcs_hfpll: clock-controller@0b016000 { > > compatible =3D "qcom,hfpll"; > > reg =3D <0x0b016000 0x30>; > > #clock-cells =3D <0>; > > clock-output-names =3D "apcs_hfpll"; > > clocks =3D <&xo_board>; > > clock-names =3D "xo"; > > }; > >=20 > > apcs_glb: mailbox@b011000 { > > compatible =3D "qcom,qcs404-apcs-apps-global",= "syscon"; > > reg =3D <0x0b011000 0x1000>; > > #mbox-cells =3D <1>; > > clocks =3D <&gcc GCC_GPLL0_AO_OUT_MAIN>, <&apc= s_hfpll>; > > clock-names =3D "aux", "pll"; > > #clock-cells =3D <0>; > > }; > >=20 > > qcs404 specifies two clocks, with an accompanied clock-name for each cl= ock. > >=20 > > msm8916 specifies a single clock, without an accompanied clock-name. > >=20 > > It is possible to append clock-names =3D "pll" for the existing clock, > > as well as to define the aux clock in the apcs node in the msm8916 DT: > > clocks =3D <&gcc GPLL0_VOTE>; > > clock-names =3D "aux"; > >=20 > > However, since the DT is treated as an ABI, the existing DT for msm8916= must > > still work, so I don't think that it is possible to ignore having backw= ards > > compability in the apcs clock driver. >=20 >=20 > so where are we with this? >=20 > do we remove backwards compatibility (see below] for v2 or is the DT=20 > really an ABI and therefore the patch under review is good as is? >=20 Breaking compatibility is up to the platform maintainers. If anything, I would make the DTS and driver changes in parallel and then remove the driver's backwards compatibility logic later on.