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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5A4B9C433EF for ; Tue, 5 Jul 2022 13:53:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229599AbiGENxS (ORCPT ); Tue, 5 Jul 2022 09:53:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40480 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233593AbiGENw5 (ORCPT ); Tue, 5 Jul 2022 09:52:57 -0400 Received: from mail-lf1-x12d.google.com (mail-lf1-x12d.google.com [IPv6:2a00:1450:4864:20::12d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AB37724BC4 for ; Tue, 5 Jul 2022 06:29:15 -0700 (PDT) Received: by mail-lf1-x12d.google.com with SMTP id f39so20571420lfv.3 for ; Tue, 05 Jul 2022 06:29:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=message-id:date:mime-version:user-agent:subject:content-language:to :cc:references:from:in-reply-to:content-transfer-encoding; bh=nm39JYdQM+q8N5iGyMJZ3ZEAI23zDoboAxiMAO40uUM=; b=udGUtSgkajAnkhEyqk7ar7DfDYjlb4YWY9RyPC4WJL1ggtFfPId+Q4QPaVWWN8GyA7 X5vF9eoyUBgK2TCl6BpcW2dmuY/WB833gaJ+qc2Am6yq3WcFf2s9xKlfGmZDzEHPEkpt HK2EiYg1e/knqI51+CkSOkpmd2pg8K0oHE8mUjkhoyNln3kwi9YTJidxXCCZgfhMpY7q Py0LV7ZX4Tg49G15GwD0Q9w8+8E9kgynu8O3uJvU1qL/4/d87dA52bMSbAtk5d5A1H4k n4b5fdtCwW6HLSJ+xBNEfccCMMeDC2OLt+UiVDWXp+iUXUtgjqY53ZRDjEMJllIyxHU1 t50g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:message-id:date:mime-version:user-agent:subject :content-language:to:cc:references:from:in-reply-to :content-transfer-encoding; bh=nm39JYdQM+q8N5iGyMJZ3ZEAI23zDoboAxiMAO40uUM=; b=f+3wWNWfPxJMkgQxr16DlJ7IOS1o0e38XejCOT8kFQPTXrVqrwXW90ee+km886B7W3 J4yqRzVin3Ia2gl1xvAYfjn1DlSrN6V/ic2ACDPCQ8tCORsyFyy8vrc9PwRXPjUxp8Ub PiPb4Bh7BTE1lSUKOrmpi/t/7yNSlQm+ISQ0bzZg0p/xSDEdHMzS9cKOIUB1DGQqe0Um tE2aedwCQE10AFKXs2taH8W3bx99EjQDTwa6wKYm8qpV1/5RoNfYKzZ21YU/l7Qqq+9V Kbr5/a9dN+kVjoY6bChviPDovCQJIkgyHDl8S/MLG7gfpRNcZNAyOmv4dqhiTpUr8Yaq HqMQ== X-Gm-Message-State: AJIora/qLaaCSWNC7qKMyGylTikJwrNk3dvQaMX7rTAWAeCx5lwWvVBw jjoloREC/MOa5yyPVjVwVppGfQ== X-Google-Smtp-Source: AGRyM1sFPLaAdklVt4AOZzb5+W6MkZnClfUpNahuDGeZX17BWf4bYDslbDazHFxrWGPTkQhHAXb1Zw== X-Received: by 2002:a05:6512:3f12:b0:47f:51de:d067 with SMTP id y18-20020a0565123f1200b0047f51ded067mr22027281lfa.146.1657027753981; Tue, 05 Jul 2022 06:29:13 -0700 (PDT) Received: from [192.168.1.52] ([84.20.121.239]) by smtp.gmail.com with ESMTPSA id t6-20020a19ad06000000b0047f933622c8sm5710456lfc.163.2022.07.05.06.29.12 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 05 Jul 2022 06:29:13 -0700 (PDT) Message-ID: Date: Tue, 5 Jul 2022 15:29:11 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.11.0 Subject: Re: [PATCH 07/11] dt-bindings: spi: spi-nxp-fspi: add a new property nxp,fspi-dll-slvdly Content-Language: en-US To: Han Xu , Bough Chen , "ashish.kumar@nxp.com" , "yogeshgaur.83@gmail.com" , "broonie@kernel.org" , "robh+dt@kernel.org" , "krzysztof.kozlowski+dt@linaro.org" , "singh.kuldeep87k@gmail.com" , "tudor.ambarus@microchip.com" , "p.yadav@ti.com" , "michael@walle.cc" , "miquel.raynal@bootlin.com" , "richard@nod.at" , "vigneshr@ti.com" , "shawnguo@kernel.org" , "s.hauer@pengutronix.de" , "kernel@pengutronix.de" Cc: "linux-spi@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "devicetree@vger.kernel.org" , "linux-mtd@lists.infradead.org" , "festevam@gmail.com" , dl-linux-imx , "linux-arm-kernel@lists.infradead.org" , "zhengxunli@mxic.com.tw" References: <1657012303-6464-1-git-send-email-haibo.chen@nxp.com> <1657012303-6464-7-git-send-email-haibo.chen@nxp.com> <59d360ef-5374-c7a7-2995-854ab3715b25@linaro.org> From: Krzysztof Kozlowski In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 05/07/2022 15:19, Han Xu wrote: >>>>> + nxp,fspi-dll-slvdly: >>>>> + $ref: /schemas/types.yaml#/definitions/uint32 >>>>> + description: | >>>>> + Specify the DLL slave line delay value. >>>> >>>> What are the units? >>> >>> Do you mean here need to give more detail explain about this properity? >>> >>> How about change like this? >>> Specify the DLL slave line delay value. The delay target for slave delay line is: >> ((nxp,fspi-dll-slvdly+1) * 1/32 * clock cycle of reference clock (serial root clock). >> >> This would be good. >> >>> The range of this value is 0~16. >> >> This needs to go to schema instead as "maximum: 16". >> >> But still the question is - what are the units used in this "delay"? ms? us? > > HI Krzysztof, > > According to the formula, the range should be 0~15, 16 should do nothing or no delay. Sure, just add some constraint. > > The unit should be clock phase. In other words, the delay can be in range of 1/32~1/2 clock cycle. So we probably misunderstood each other... looking at the driver it also explains the confusing. You encoded here register value which is pretty often wrong approach. This should be instead meaningful value for the user of the bindings, so usually using one of property units: https://github.com/devicetree-org/dt-schema/blob/main/dtschema/schemas/property-units.yaml I think you could use here clock cycles or clock phase, but then it has to be obvious it is that unit. Best regards, Krzysztof