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=-5.2 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable 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 F2661C433E0 for ; Mon, 6 Jul 2020 15:19:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CB6BE20715 for ; Mon, 6 Jul 2020 15:19:48 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=fastree3d-com.20150623.gappssmtp.com header.i=@fastree3d-com.20150623.gappssmtp.com header.b="MJtJazoU" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729328AbgGFPTr (ORCPT ); Mon, 6 Jul 2020 11:19:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35536 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729254AbgGFPTq (ORCPT ); Mon, 6 Jul 2020 11:19:46 -0400 Received: from mail-ej1-x641.google.com (mail-ej1-x641.google.com [IPv6:2a00:1450:4864:20::641]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9F5C3C08C5DF for ; Mon, 6 Jul 2020 08:19:46 -0700 (PDT) Received: by mail-ej1-x641.google.com with SMTP id l12so42915678ejn.10 for ; Mon, 06 Jul 2020 08:19:46 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fastree3d-com.20150623.gappssmtp.com; s=20150623; h=from:subject:to:cc:references:message-id:date:user-agent :mime-version:in-reply-to:content-transfer-encoding:content-language; bh=/xxuSBaFwBsMKWLj22wDWl27eYoU7MIEcxTocbJmKvI=; b=MJtJazoU44U9pCLcGCNygqUIC40Jd8PYw5hLDFzG/7qpB7d7QZGYRssWokpQfub+1f Irfc2f1D5mxLKLDlMwZP2s7FyDna31thh8K/r1yuY9LYuvYINuQ21vyasvwr/p+pxyWY CxjFxYtQGbbaDb5x4txLeJ1QTdjWnWe/4/kCc02oNKaeqKtQlDXg7MBLBuW78VZWYnOH QOKyknnCQRxsDLx3scBYQgh/tFWKOzEDXtkXzC7u1YqCn/eYY1n/WjDegv0rc9/4qxsp 8GYahdbmXkaRyilNMhigDIXvq9pmTkZSW6EpizC4hQA2V0Z/A3D+LnlujfejlYX2pfGm 0Puw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:subject:to:cc:references:message-id:date :user-agent:mime-version:in-reply-to:content-transfer-encoding :content-language; bh=/xxuSBaFwBsMKWLj22wDWl27eYoU7MIEcxTocbJmKvI=; b=B9hbN7Vwx59ih6JCZX8rhWr/YZui3IqRVEyC4LaAmoKztZMCLjIgCXZM9tbqcXGooN QZCV32YZjNaMhOeoCvEp/ZYvECZNzd9fg5N3wQ/DqpPipJsVvtYl8eNkXvB0xWQFCOuM rE81OEysSnirgNfC2VS4Z5tATVi4MlyXza7JSuqyyem7NvRrFgxXF4ohTyBhmz8jat9J qof5qjylZ/7972/vMXsOie+roVQO1HuQmmmhsKPmacqo8+/XG7I24uM61pNYxzs9o1R+ +zAvLIaUcuPow01SrICR1Ay74D1x4lqX7S2PxFhVdXxDkkW4IaeuZUmFRtURnt0tFCxK wxig== X-Gm-Message-State: AOAM533SZ6MEN6h+kVgcV3waX/sT/vAqAuty7yIqtF7TMp/nhJx1PdFs NmQ46xX2hQuSil9I7P/JPBNMPdcD9Q== X-Google-Smtp-Source: ABdhPJwtkXu2xRZaKI169jRI14Ab1BOD0pJ1Z6zjsYnl3WDuq/VWuYjFuv5XT2ZZ2YSQRGcFl/ARhA== X-Received: by 2002:a17:906:3146:: with SMTP id e6mr35109494eje.2.1594048784895; Mon, 06 Jul 2020 08:19:44 -0700 (PDT) Received: from [192.168.33.195] (fastree1.epfl.ch. [192.26.37.52]) by smtp.gmail.com with ESMTPSA id gr15sm16590843ejb.84.2020.07.06.08.19.43 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 06 Jul 2020 08:19:43 -0700 (PDT) From: Adrian Fiergolski X-Google-Original-From: Adrian Fiergolski Subject: Re: [PATCH v2 2/2] dt-bindings: Add documentation for SPI daisy chain driver. To: Geert Uytterhoeven Cc: Lukas Wunner , Mark Brown , Rob Herring , linux-spi , "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" , Linux Kernel Mailing List References: <202007040833.xIqR5rAw%lkp@intel.com> <20200706092247.20740-1-adrian.fiergolski@fastree3d.com> <20200706092247.20740-2-adrian.fiergolski@fastree3d.com> Message-ID: Date: Mon, 6 Jul 2020 17:19:42 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Firefox/68.0 Thunderbird/68.9.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Content-Language: en-GB Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Geert, Thank you for your reply. On 06.07.2020 17:10, Geert Uytterhoeven wrote: > Hi Adrian, > > On Mon, Jul 6, 2020 at 11:23 AM Adrian Fiergolski > wrote: >> Add documentation for SPI daisy chain driver. >> >> Signed-off-by: Adrian Fiergolski > Thanks for your patch! > >> --- /dev/null >> +++ b/Documentation/devicetree/bindings/spi/spi-daisy_chain.txt >> @@ -0,0 +1,56 @@ >> +spi-daisy_chain : The driver handling SPI daisy chains. >> +----------------------------------------------------------- >> + >> +Required properties: >> +- compatible : Should be "spi,daisy_chain" >> +- reg : Chip select assigned to the chain >> + >> + For the SPI devices on a common SPI chain - nodes of daisy_chain): >> +- spi-daisy-chain-len : Length (in bytes) of the SPI transfer, >> + when the SPI device is part of a device chain. >> +- spi-daisy-chain-noop : Byte string of no-operation command which should >> + be send when device is not addressed during the >> + given SPI transfer > The above two properties are device-specific, and the same for all > devices of the same type, thus leading to duplication. > Hence I think this should not be specified in DT, but instead handled > by the driver. I.e. for Linux, you would retrieve this from struct > spi_device, as filled in by the slave driver. The problem is that then this patch would not be compatible out of the box with all SPI devices (as it's now) and would require rewrite (adding this extra information in the spi_driver struct) of all SPI drivers which support daisy chain. Regards, Adrian