From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org ([198.145.29.99]:35946 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751431AbeDROAV (ORCPT ); Wed, 18 Apr 2018 10:00:21 -0400 MIME-Version: 1.0 In-Reply-To: <584aca6c-c87a-ff7a-2fdc-3c742236be60@linux.intel.com> References: <20180410183212.16787-1-jae.hyun.yoo@linux.intel.com> <20180410183212.16787-5-jae.hyun.yoo@linux.intel.com> <20180416181035.rcjvt4rlrwaj5yxf@rob-hp-laptop> <53ff5b2b-eba8-8311-64a9-abd4bc72226d@linux.intel.com> <584aca6c-c87a-ff7a-2fdc-3c742236be60@linux.intel.com> From: Rob Herring Date: Wed, 18 Apr 2018 08:59:58 -0500 Message-ID: Subject: Re: [PATCH v3 04/10] Documentations: dt-bindings: Add a document of PECI adapter driver for Aspeed AST24xx/25xx SoCs To: Jae Hyun Yoo Cc: Alan Cox , Andrew Jeffery , Andrew Lunn , Andy Shevchenko , Arnd Bergmann , Benjamin Herrenschmidt , Fengguang Wu , Greg KH , Guenter Roeck , Haiyue Wang , James Feist , Jason M Biils , Jean Delvare , Joel Stanley , Julia Cartwright , Miguel Ojeda , Milton Miller II , Pavel Machek , Randy Dunlap , Stef van Os , Sumeet R Pawnikar , Vernon Mauery , "linux-kernel@vger.kernel.org" , linux-doc@vger.kernel.org, devicetree@vger.kernel.org, Linux HWMON List , "moderated list:ARM/FREESCALE IMX / MXC ARM ARCHITECTURE" , OpenBMC Maillist Content-Type: text/plain; charset="UTF-8" Sender: linux-hwmon-owner@vger.kernel.org List-Id: linux-hwmon@vger.kernel.org On Tue, Apr 17, 2018 at 5:06 PM, Jae Hyun Yoo wrote: > On 4/17/2018 11:16 AM, Jae Hyun Yoo wrote: >> >> On 4/17/2018 6:16 AM, Rob Herring wrote: >>> >>> On Mon, Apr 16, 2018 at 6:12 PM, Jae Hyun Yoo >>> wrote: >>>> >>>> On 4/16/2018 11:10 AM, Rob Herring wrote: >>>>> >>>>> >>>>> On Tue, Apr 10, 2018 at 11:32:06AM -0700, Jae Hyun Yoo wrote: >>>>>> >>>>>> >>>>>> This commit adds a dt-bindings document of PECI adapter driver for >>>>>> Aspeed >>>>>> AST24xx/25xx SoCs. >>> >>> >>> [...] >>> >>>>>> +- clocks : Should contain clock source for PECI >>>>>> controller. >>>>>> + Should reference clkin. >>>>>> +- clock_frequency : Should contain the operation frequency of PECI >>>>>> controller >>>>>> + in units of Hz. >>>>>> + 187500 ~ 24000000 >>>>> >>>>> >>>>> >>>>> This is the frequency of the bus or used to derive it? It would be >>>>> better to specify the bus frequency instead and have the driver >>>>> calculate its internal freq. And then use "bus-frequency" instead. >>>>> >>>> >>>> I agree with you. Actually, it is being used for operation frequency >>>> setting >>>> of PECI controller module in SoC so it's different from the meaning of >>>> "bus-frequency". I'll change it to "operation-frequency". >>> >>> >>> No, now you've gone from a standard property name to something custom. >>> Why do you need to set the frequency in DT if it is not related to the >>> interface frequency? >>> >>> Rob >>> >> >> Actually, the interface frequency is affected by the operation frequency >> but there is no description of its relationship in datasheet. I'll check >> again about the detail to ASPEED chip vendor and will use >> 'bus-frequency' if available. >> > > I investigated it more deeply. Basically, by the spec, PECI bus speed > cannot be set as a fixed speed. A PECI bus can have a wide speed range > from 2Kbps to 2Mbps which is dynamically set by a handshaking sequence > between an originator and clients called 'timing negotiation' in spec. > This timing negotiation behavior happens on every single transaction so the > bus speed also can vary on every transactions. So I'm thinking a custom > property name for it, 'peci-clk-frequency' if it is acceptable. Okay, seems bus-frequency is not appropriate here. So use 'clock-frequency' (note the '-' not '_' as that is the standard property). Rob From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rob Herring Subject: Re: [PATCH v3 04/10] Documentations: dt-bindings: Add a document of PECI adapter driver for Aspeed AST24xx/25xx SoCs Date: Wed, 18 Apr 2018 08:59:58 -0500 Message-ID: References: <20180410183212.16787-1-jae.hyun.yoo@linux.intel.com> <20180410183212.16787-5-jae.hyun.yoo@linux.intel.com> <20180416181035.rcjvt4rlrwaj5yxf@rob-hp-laptop> <53ff5b2b-eba8-8311-64a9-abd4bc72226d@linux.intel.com> <584aca6c-c87a-ff7a-2fdc-3c742236be60@linux.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Return-path: In-Reply-To: <584aca6c-c87a-ff7a-2fdc-3c742236be60@linux.intel.com> Sender: linux-kernel-owner@vger.kernel.org To: Jae Hyun Yoo Cc: Alan Cox , Andrew Jeffery , Andrew Lunn , Andy Shevchenko , Arnd Bergmann , Benjamin Herrenschmidt , Fengguang Wu , Greg KH , Guenter Roeck , Haiyue Wang , James Feist , Jason M Biils , Jean Delvare , Joel Stanley , Julia Cartwright , Miguel Ojeda , Milton Miller II , Pavel Machek , Randy Dunlap , Stef van Os List-Id: devicetree@vger.kernel.org On Tue, Apr 17, 2018 at 5:06 PM, Jae Hyun Yoo wrote: > On 4/17/2018 11:16 AM, Jae Hyun Yoo wrote: >> >> On 4/17/2018 6:16 AM, Rob Herring wrote: >>> >>> On Mon, Apr 16, 2018 at 6:12 PM, Jae Hyun Yoo >>> wrote: >>>> >>>> On 4/16/2018 11:10 AM, Rob Herring wrote: >>>>> >>>>> >>>>> On Tue, Apr 10, 2018 at 11:32:06AM -0700, Jae Hyun Yoo wrote: >>>>>> >>>>>> >>>>>> This commit adds a dt-bindings document of PECI adapter driver for >>>>>> Aspeed >>>>>> AST24xx/25xx SoCs. >>> >>> >>> [...] >>> >>>>>> +- clocks : Should contain clock source for PECI >>>>>> controller. >>>>>> + Should reference clkin. >>>>>> +- clock_frequency : Should contain the operation frequency of PECI >>>>>> controller >>>>>> + in units of Hz. >>>>>> + 187500 ~ 24000000 >>>>> >>>>> >>>>> >>>>> This is the frequency of the bus or used to derive it? It would be >>>>> better to specify the bus frequency instead and have the driver >>>>> calculate its internal freq. And then use "bus-frequency" instead. >>>>> >>>> >>>> I agree with you. Actually, it is being used for operation frequency >>>> setting >>>> of PECI controller module in SoC so it's different from the meaning of >>>> "bus-frequency". I'll change it to "operation-frequency". >>> >>> >>> No, now you've gone from a standard property name to something custom. >>> Why do you need to set the frequency in DT if it is not related to the >>> interface frequency? >>> >>> Rob >>> >> >> Actually, the interface frequency is affected by the operation frequency >> but there is no description of its relationship in datasheet. I'll check >> again about the detail to ASPEED chip vendor and will use >> 'bus-frequency' if available. >> > > I investigated it more deeply. Basically, by the spec, PECI bus speed > cannot be set as a fixed speed. A PECI bus can have a wide speed range > from 2Kbps to 2Mbps which is dynamically set by a handshaking sequence > between an originator and clients called 'timing negotiation' in spec. > This timing negotiation behavior happens on every single transaction so the > bus speed also can vary on every transactions. So I'm thinking a custom > property name for it, 'peci-clk-frequency' if it is acceptable. Okay, seems bus-frequency is not appropriate here. So use 'clock-frequency' (note the '-' not '_' as that is the standard property). Rob From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.1 (2015-04-28) on archive.lwn.net X-Spam-Level: X-Spam-Status: No, score=-6.0 required=5.0 tests=MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham autolearn_force=no version=3.4.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by archive.lwn.net (Postfix) with ESMTP id 407847DE78 for ; Wed, 18 Apr 2018 14:00:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753133AbeDROAW (ORCPT ); Wed, 18 Apr 2018 10:00:22 -0400 Received: from mail.kernel.org ([198.145.29.99]:35946 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751431AbeDROAV (ORCPT ); Wed, 18 Apr 2018 10:00:21 -0400 Received: from mail-qt0-f171.google.com (mail-qt0-f171.google.com [209.85.216.171]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 2BB2A21840; Wed, 18 Apr 2018 14:00:20 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2BB2A21840 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=robh@kernel.org Received: by mail-qt0-f171.google.com with SMTP id p9-v6so1878773qtn.0; Wed, 18 Apr 2018 07:00:20 -0700 (PDT) X-Gm-Message-State: ALQs6tArXy3DR+fDcDy7JpcPKUbgIXfump7cHRIV6YHKtx+Lc9jsullZ NgU8GFBonlOMJR2LkCWX7ssT7wcknbRwmzeRDg== X-Google-Smtp-Source: AIpwx49mm2xP9Gr5suTrAPZYuUEqftMkc80NE5zEMrz9RKJHiEd5kddN0kxuhcBF/E45ZJhLEi+F55L6diO4AVQIQ/8= X-Received: by 2002:ac8:1e9d:: with SMTP id c29-v6mr2427652qtm.354.1524060018515; Wed, 18 Apr 2018 07:00:18 -0700 (PDT) MIME-Version: 1.0 Received: by 10.12.163.228 with HTTP; Wed, 18 Apr 2018 06:59:58 -0700 (PDT) In-Reply-To: <584aca6c-c87a-ff7a-2fdc-3c742236be60@linux.intel.com> References: <20180410183212.16787-1-jae.hyun.yoo@linux.intel.com> <20180410183212.16787-5-jae.hyun.yoo@linux.intel.com> <20180416181035.rcjvt4rlrwaj5yxf@rob-hp-laptop> <53ff5b2b-eba8-8311-64a9-abd4bc72226d@linux.intel.com> <584aca6c-c87a-ff7a-2fdc-3c742236be60@linux.intel.com> From: Rob Herring Date: Wed, 18 Apr 2018 08:59:58 -0500 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH v3 04/10] Documentations: dt-bindings: Add a document of PECI adapter driver for Aspeed AST24xx/25xx SoCs To: Jae Hyun Yoo Cc: Alan Cox , Andrew Jeffery , Andrew Lunn , Andy Shevchenko , Arnd Bergmann , Benjamin Herrenschmidt , Fengguang Wu , Greg KH , Guenter Roeck , Haiyue Wang , James Feist , Jason M Biils , Jean Delvare , Joel Stanley , Julia Cartwright , Miguel Ojeda , Milton Miller II , Pavel Machek , Randy Dunlap , Stef van Os , Sumeet R Pawnikar , Vernon Mauery , "linux-kernel@vger.kernel.org" , linux-doc@vger.kernel.org, devicetree@vger.kernel.org, Linux HWMON List , "moderated list:ARM/FREESCALE IMX / MXC ARM ARCHITECTURE" , OpenBMC Maillist Content-Type: text/plain; charset="UTF-8" Sender: linux-doc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org On Tue, Apr 17, 2018 at 5:06 PM, Jae Hyun Yoo wrote: > On 4/17/2018 11:16 AM, Jae Hyun Yoo wrote: >> >> On 4/17/2018 6:16 AM, Rob Herring wrote: >>> >>> On Mon, Apr 16, 2018 at 6:12 PM, Jae Hyun Yoo >>> wrote: >>>> >>>> On 4/16/2018 11:10 AM, Rob Herring wrote: >>>>> >>>>> >>>>> On Tue, Apr 10, 2018 at 11:32:06AM -0700, Jae Hyun Yoo wrote: >>>>>> >>>>>> >>>>>> This commit adds a dt-bindings document of PECI adapter driver for >>>>>> Aspeed >>>>>> AST24xx/25xx SoCs. >>> >>> >>> [...] >>> >>>>>> +- clocks : Should contain clock source for PECI >>>>>> controller. >>>>>> + Should reference clkin. >>>>>> +- clock_frequency : Should contain the operation frequency of PECI >>>>>> controller >>>>>> + in units of Hz. >>>>>> + 187500 ~ 24000000 >>>>> >>>>> >>>>> >>>>> This is the frequency of the bus or used to derive it? It would be >>>>> better to specify the bus frequency instead and have the driver >>>>> calculate its internal freq. And then use "bus-frequency" instead. >>>>> >>>> >>>> I agree with you. Actually, it is being used for operation frequency >>>> setting >>>> of PECI controller module in SoC so it's different from the meaning of >>>> "bus-frequency". I'll change it to "operation-frequency". >>> >>> >>> No, now you've gone from a standard property name to something custom. >>> Why do you need to set the frequency in DT if it is not related to the >>> interface frequency? >>> >>> Rob >>> >> >> Actually, the interface frequency is affected by the operation frequency >> but there is no description of its relationship in datasheet. I'll check >> again about the detail to ASPEED chip vendor and will use >> 'bus-frequency' if available. >> > > I investigated it more deeply. Basically, by the spec, PECI bus speed > cannot be set as a fixed speed. A PECI bus can have a wide speed range > from 2Kbps to 2Mbps which is dynamically set by a handshaking sequence > between an originator and clients called 'timing negotiation' in spec. > This timing negotiation behavior happens on every single transaction so the > bus speed also can vary on every transactions. So I'm thinking a custom > property name for it, 'peci-clk-frequency' if it is acceptable. Okay, seems bus-frequency is not appropriate here. So use 'clock-frequency' (note the '-' not '_' as that is the standard property). Rob -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Authentication-Results: lists.ozlabs.org; spf=none (mailfrom) smtp.mailfrom=kernel.org (client-ip=198.145.29.99; helo=mail.kernel.org; envelope-from=robh@kernel.org; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 40R3fb2n9KzF1y2 for ; Thu, 19 Apr 2018 00:00:22 +1000 (AEST) Received: from mail-qt0-f178.google.com (mail-qt0-f178.google.com [209.85.216.178]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 6AE532184D for ; Wed, 18 Apr 2018 14:00:20 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6AE532184D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=robh@kernel.org Received: by mail-qt0-f178.google.com with SMTP id z23-v6so1863032qti.5 for ; Wed, 18 Apr 2018 07:00:20 -0700 (PDT) X-Gm-Message-State: ALQs6tAgYVA25W5KWj4vBPcdofx21qDLGAgy4VQAdSyxmA5A0RXFCetZ SouSdKpwJzZemdDtn/a5pyGj+Or8G4hMCh4JxA== X-Google-Smtp-Source: AIpwx49mm2xP9Gr5suTrAPZYuUEqftMkc80NE5zEMrz9RKJHiEd5kddN0kxuhcBF/E45ZJhLEi+F55L6diO4AVQIQ/8= X-Received: by 2002:ac8:1e9d:: with SMTP id c29-v6mr2427652qtm.354.1524060018515; Wed, 18 Apr 2018 07:00:18 -0700 (PDT) MIME-Version: 1.0 Received: by 10.12.163.228 with HTTP; Wed, 18 Apr 2018 06:59:58 -0700 (PDT) In-Reply-To: <584aca6c-c87a-ff7a-2fdc-3c742236be60@linux.intel.com> References: <20180410183212.16787-1-jae.hyun.yoo@linux.intel.com> <20180410183212.16787-5-jae.hyun.yoo@linux.intel.com> <20180416181035.rcjvt4rlrwaj5yxf@rob-hp-laptop> <53ff5b2b-eba8-8311-64a9-abd4bc72226d@linux.intel.com> <584aca6c-c87a-ff7a-2fdc-3c742236be60@linux.intel.com> From: Rob Herring Date: Wed, 18 Apr 2018 08:59:58 -0500 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH v3 04/10] Documentations: dt-bindings: Add a document of PECI adapter driver for Aspeed AST24xx/25xx SoCs To: Jae Hyun Yoo Cc: Alan Cox , Andrew Jeffery , Andrew Lunn , Andy Shevchenko , Arnd Bergmann , Benjamin Herrenschmidt , Fengguang Wu , Greg KH , Guenter Roeck , Haiyue Wang , James Feist , Jason M Biils , Jean Delvare , Joel Stanley , Julia Cartwright , Miguel Ojeda , Milton Miller II , Pavel Machek , Randy Dunlap , Stef van Os , Sumeet R Pawnikar , Vernon Mauery , "linux-kernel@vger.kernel.org" , linux-doc@vger.kernel.org, devicetree@vger.kernel.org, Linux HWMON List , "moderated list:ARM/FREESCALE IMX / MXC ARM ARCHITECTURE" , OpenBMC Maillist Content-Type: text/plain; charset="UTF-8" X-BeenThere: openbmc@lists.ozlabs.org X-Mailman-Version: 2.1.26 Precedence: list List-Id: Development list for OpenBMC List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 18 Apr 2018 14:00:24 -0000 On Tue, Apr 17, 2018 at 5:06 PM, Jae Hyun Yoo wrote: > On 4/17/2018 11:16 AM, Jae Hyun Yoo wrote: >> >> On 4/17/2018 6:16 AM, Rob Herring wrote: >>> >>> On Mon, Apr 16, 2018 at 6:12 PM, Jae Hyun Yoo >>> wrote: >>>> >>>> On 4/16/2018 11:10 AM, Rob Herring wrote: >>>>> >>>>> >>>>> On Tue, Apr 10, 2018 at 11:32:06AM -0700, Jae Hyun Yoo wrote: >>>>>> >>>>>> >>>>>> This commit adds a dt-bindings document of PECI adapter driver for >>>>>> Aspeed >>>>>> AST24xx/25xx SoCs. >>> >>> >>> [...] >>> >>>>>> +- clocks : Should contain clock source for PECI >>>>>> controller. >>>>>> + Should reference clkin. >>>>>> +- clock_frequency : Should contain the operation frequency of PECI >>>>>> controller >>>>>> + in units of Hz. >>>>>> + 187500 ~ 24000000 >>>>> >>>>> >>>>> >>>>> This is the frequency of the bus or used to derive it? It would be >>>>> better to specify the bus frequency instead and have the driver >>>>> calculate its internal freq. And then use "bus-frequency" instead. >>>>> >>>> >>>> I agree with you. Actually, it is being used for operation frequency >>>> setting >>>> of PECI controller module in SoC so it's different from the meaning of >>>> "bus-frequency". I'll change it to "operation-frequency". >>> >>> >>> No, now you've gone from a standard property name to something custom. >>> Why do you need to set the frequency in DT if it is not related to the >>> interface frequency? >>> >>> Rob >>> >> >> Actually, the interface frequency is affected by the operation frequency >> but there is no description of its relationship in datasheet. I'll check >> again about the detail to ASPEED chip vendor and will use >> 'bus-frequency' if available. >> > > I investigated it more deeply. Basically, by the spec, PECI bus speed > cannot be set as a fixed speed. A PECI bus can have a wide speed range > from 2Kbps to 2Mbps which is dynamically set by a handshaking sequence > between an originator and clients called 'timing negotiation' in spec. > This timing negotiation behavior happens on every single transaction so the > bus speed also can vary on every transactions. So I'm thinking a custom > property name for it, 'peci-clk-frequency' if it is acceptable. Okay, seems bus-frequency is not appropriate here. So use 'clock-frequency' (note the '-' not '_' as that is the standard property). Rob From mboxrd@z Thu Jan 1 00:00:00 1970 From: robh@kernel.org (Rob Herring) Date: Wed, 18 Apr 2018 08:59:58 -0500 Subject: [PATCH v3 04/10] Documentations: dt-bindings: Add a document of PECI adapter driver for Aspeed AST24xx/25xx SoCs In-Reply-To: <584aca6c-c87a-ff7a-2fdc-3c742236be60@linux.intel.com> References: <20180410183212.16787-1-jae.hyun.yoo@linux.intel.com> <20180410183212.16787-5-jae.hyun.yoo@linux.intel.com> <20180416181035.rcjvt4rlrwaj5yxf@rob-hp-laptop> <53ff5b2b-eba8-8311-64a9-abd4bc72226d@linux.intel.com> <584aca6c-c87a-ff7a-2fdc-3c742236be60@linux.intel.com> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Tue, Apr 17, 2018 at 5:06 PM, Jae Hyun Yoo wrote: > On 4/17/2018 11:16 AM, Jae Hyun Yoo wrote: >> >> On 4/17/2018 6:16 AM, Rob Herring wrote: >>> >>> On Mon, Apr 16, 2018 at 6:12 PM, Jae Hyun Yoo >>> wrote: >>>> >>>> On 4/16/2018 11:10 AM, Rob Herring wrote: >>>>> >>>>> >>>>> On Tue, Apr 10, 2018 at 11:32:06AM -0700, Jae Hyun Yoo wrote: >>>>>> >>>>>> >>>>>> This commit adds a dt-bindings document of PECI adapter driver for >>>>>> Aspeed >>>>>> AST24xx/25xx SoCs. >>> >>> >>> [...] >>> >>>>>> +- clocks : Should contain clock source for PECI >>>>>> controller. >>>>>> + Should reference clkin. >>>>>> +- clock_frequency : Should contain the operation frequency of PECI >>>>>> controller >>>>>> + in units of Hz. >>>>>> + 187500 ~ 24000000 >>>>> >>>>> >>>>> >>>>> This is the frequency of the bus or used to derive it? It would be >>>>> better to specify the bus frequency instead and have the driver >>>>> calculate its internal freq. And then use "bus-frequency" instead. >>>>> >>>> >>>> I agree with you. Actually, it is being used for operation frequency >>>> setting >>>> of PECI controller module in SoC so it's different from the meaning of >>>> "bus-frequency". I'll change it to "operation-frequency". >>> >>> >>> No, now you've gone from a standard property name to something custom. >>> Why do you need to set the frequency in DT if it is not related to the >>> interface frequency? >>> >>> Rob >>> >> >> Actually, the interface frequency is affected by the operation frequency >> but there is no description of its relationship in datasheet. I'll check >> again about the detail to ASPEED chip vendor and will use >> 'bus-frequency' if available. >> > > I investigated it more deeply. Basically, by the spec, PECI bus speed > cannot be set as a fixed speed. A PECI bus can have a wide speed range > from 2Kbps to 2Mbps which is dynamically set by a handshaking sequence > between an originator and clients called 'timing negotiation' in spec. > This timing negotiation behavior happens on every single transaction so the > bus speed also can vary on every transactions. So I'm thinking a custom > property name for it, 'peci-clk-frequency' if it is acceptable. Okay, seems bus-frequency is not appropriate here. So use 'clock-frequency' (note the '-' not '_' as that is the standard property). Rob