Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752169AbaKFJLe (ORCPT ); Thu, 6 Nov 2014 04:11:34 -0500 Received: from mail-wi0-f178.google.com ([209.85.212.178]:54063 "EHLO mail-wi0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750901AbaKFJLW (ORCPT ); Thu, 6 Nov 2014 04:11:22 -0500 MIME-Version: 1.0 In-Reply-To: <545B172C.4060105@nvidia.com> References: <1414599796-30597-1-git-send-email-tomeu.vizoso@collabora.com> <1414599796-30597-5-git-send-email-tomeu.vizoso@collabora.com> <545B172C.4060105@nvidia.com> From: Tomeu Vizoso Date: Thu, 6 Nov 2014 10:11:00 +0100 X-Google-Sender-Auth: 7NL0KwSk-Mxn5DvTsTeXW-x1D8g Message-ID: Subject: Re: [PATCH v3 04/13] of: document new emc-timings subnode in nvidia,tegra124-car To: Alexandre Courbot Cc: "linux-tegra@vger.kernel.org" , Javier Martinez Canillas , Rob Herring , Pawel Moll , Mark Rutland , Ian Campbell , Kumar Gala , Stephen Warren , Thierry Reding , Alexandre Courbot , Peter De Schrijver , "devicetree@vger.kernel.org" , "linux-kernel@vger.kernel.org" Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 6 November 2014 07:37, Alexandre Courbot wrote: > On 10/30/2014 01:22 AM, Tomeu Vizoso wrote: >> >> The EMC clock needs some extra information for changing its rate. >> >> Signed-off-by: Tomeu Vizoso >> --- >> .../bindings/clock/nvidia,tegra124-car.txt | 46 >> +++++++++++++++++++++- >> 1 file changed, 44 insertions(+), 2 deletions(-) >> >> diff --git >> a/Documentation/devicetree/bindings/clock/nvidia,tegra124-car.txt >> b/Documentation/devicetree/bindings/clock/nvidia,tegra124-car.txt >> index ded5d62..42e0588 100644 >> --- a/Documentation/devicetree/bindings/clock/nvidia,tegra124-car.txt >> +++ b/Documentation/devicetree/bindings/clock/nvidia,tegra124-car.txt >> @@ -19,12 +19,35 @@ Required properties : >> In clock consumers, this cell represents the bit number in the CAR's >> array of CLK_RST_CONTROLLER_RST_DEVICES_* registers. >> >> +The node should contain a "emc-timings" subnode for each supported RAM >> type (see >> +field RAM_CODE in register PMC_STRAPPING_OPT_A), with its unit address >> being its >> +RAM_CODE. >> + >> +Required properties for "emc-timings" nodes : >> +- nvidia,ram-code : Should contain the value of RAM_CODE this timing set >> + is used for. >> + >> +Each "emc-timings" node should contain a "timing" subnode for every >> supported >> +EMC clock rate. The "timing" subnodes should have the clock rate in Hz as >> their >> +unit address. > > > This seems to be a quite liberal use of unit addresses (same in the next > patch) - is this allowed by DT? Well, it's not that different from using the register address. I think it helps with readability more than an arbitrary index. >> + >> +Required properties for "timing" nodes : >> +- clock-frequency : Should contain the memory clock rate to which this >> timing >> +relates. >> +- nvidia,parent-clock-frequency : Should contain the rate at which the >> current >> +parent of the EMC clock should be running at this timing. >> +- clocks : Must contain an entry for each entry in clock-names. >> + See ../clocks/clock-bindings.txt for details. >> +- clock-names : Must include the following entries: >> + - emc-parent : the clock that should be the parent of the EMC clock at >> this >> +timing. >> + >> Example SoC include file: >> >> / { >> - tegra_car: clock { >> + tegra_car: clock@0,60006000 { >> compatible = "nvidia,tegra124-car"; >> - reg = <0x60006000 0x1000>; >> + reg = <0x0 0x60006000 0x0 0x1000>; >> #clock-cells = <1>; >> #reset-cells = <1>; >> }; >> @@ -60,4 +83,23 @@ Example board file: >> &tegra_car { >> clocks = <&clk_32k> <&osc>; >> }; >> + >> + clock@0,60006000 { >> + emc-timings@3 { >> + nvidia,ram-code = <3>; >> + >> + timing@12750000 { >> + clock-frequency = <12750000>; >> + nvidia,parent-clock-frequency = >> <408000000>; >> + clocks = <&tegra_car TEGRA124_CLK_PLL_P>; >> + clock-names = "emc-parent"; >> + }; >> + timing@20400000 { >> + clock-frequency = <20400000>; >> + nvidia,parent-clock-frequency = >> <408000000>; >> + clocks = <&tegra_car TEGRA124_CLK_PLL_P>; >> + clock-names = "emc-parent"; >> + }; >> + }; >> + }; > > > At first it seems confusing to see a top-level node without a compatible > property, until you realize it has already been defined before. > > In patch 05, you put "Example board file:" above a similar node, which is > enough to lift that ambiguity - could you do the same here? Oh, actually it was already in the file. I took this idea from here for patch 05. Thanks, Tomeu > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/