Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752112AbaKGFbk (ORCPT ); Fri, 7 Nov 2014 00:31:40 -0500 Received: from hqemgate14.nvidia.com ([216.228.121.143]:16715 "EHLO hqemgate14.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752071AbaKGFbf (ORCPT ); Fri, 7 Nov 2014 00:31:35 -0500 X-PGP-Universal: processed; by hqnvupgp08.nvidia.com on Thu, 06 Nov 2014 21:30:39 -0800 Message-ID: <545C5927.3010001@nvidia.com> Date: Fri, 7 Nov 2014 14:31:19 +0900 From: Alexandre Courbot Organization: NVIDIA User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.2.0 MIME-Version: 1.0 To: Rob Herring CC: Tomeu Vizoso , "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" Subject: Re: [PATCH v3 04/13] of: document new emc-timings subnode in nvidia,tegra124-car 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> In-Reply-To: X-NVConfidentiality: public X-Originating-IP: [10.19.57.128] X-ClientProxiedBy: HKMAIL104.nvidia.com (10.18.16.13) To HKMAIL102.nvidia.com (10.18.16.11) Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/07/2014 12:12 AM, Rob Herring wrote: > On Thu, Nov 6, 2014 at 12:37 AM, 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? > > No, unit address should match a reg property. Mmm, would you have any suggestion as to how this can be fixed? Right now what I can think of is either to replace the "clock-frequency" property by "reg" (which would be confusing), or to use a different naming scheme, e.g. timing-12750000. IIUC the naming is not essential for properly parsing these nodes, so maybe the second solution is the way to go? > >>> + >>> +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 { > > The comma here is wrong. Commas should be used when you have something > like PCI bus:dev:func for addressing. > >>> compatible = "nvidia,tegra124-car"; >>> - reg = <0x60006000 0x1000>; >>> + reg = <0x0 0x60006000 0x0 0x1000>; > > The number of cell's is really irrelevant to the example. > >>> #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"; > > Why do you need both clocks and hardcoded values? clock-frequency is > the desired freq you want to set TEGRA124_CLK_PLL_P to? That would be nvidia,parent-clock-frequency IIUC, while clock-frequency is the resulting EMC clock. > > The clocks property really belongs as part of the memory controller > node or a memory device node. I would tend to agree here. Tomeu, does it make sense to move these properties to the EMC driver instead? -- 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/