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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 9E9EDC4332D for ; Fri, 20 Mar 2020 17:57:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7A49320663 for ; Fri, 20 Mar 2020 17:57:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727041AbgCTR5y (ORCPT ); Fri, 20 Mar 2020 13:57:54 -0400 Received: from mga01.intel.com ([192.55.52.88]:31292 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725446AbgCTR5y (ORCPT ); Fri, 20 Mar 2020 13:57:54 -0400 IronPort-SDR: r71geOQEIaSfWMZJ6TeJbS80s1s4UME7czaI12BpC1s26yRlO7uVuXBjy12s3QaWK7/0Uj2sMi 625iUw2EwMPA== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga004.jf.intel.com ([10.7.209.38]) by fmsmga101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 20 Mar 2020 10:57:53 -0700 IronPort-SDR: OmDXVhyTKlU50WoWzpmVCqcLA7WUwVpCf1Ao7u1nBnBGKJ/i2veDk5SXC5PBRgALl8UdNfmn1Z JPTfAOqQ1bEQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.72,285,1580803200"; d="scan'208";a="392225793" Received: from manallet-mobl.amr.corp.intel.com (HELO [10.255.34.12]) ([10.255.34.12]) by orsmga004.jf.intel.com with ESMTP; 20 Mar 2020 10:57:50 -0700 Subject: Re: [PATCH 5/5] soundwire: qcom: add sdw_master_device support To: Srinivas Kandagatla , alsa-devel@alsa-project.org Cc: tiwai@suse.de, gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, Ranjani Sridharan , Hui Wang , vkoul@kernel.org, broonie@kernel.org, Andy Gross , jank@cadence.com, "open list:ARM/QUALCOMM SUPPORT" , slawomir.blauciak@intel.com, Sanyog Kale , Bjorn Andersson , Bard liao , Rander Wang References: <20200320162947.17663-1-pierre-louis.bossart@linux.intel.com> <20200320162947.17663-6-pierre-louis.bossart@linux.intel.com> <81e2101e-d7ce-d023-5c35-ac6b55ea7166@linaro.org> From: Pierre-Louis Bossart Message-ID: <40803069-e7dc-3dd6-ec7b-bec4308f381e@linux.intel.com> Date: Fri, 20 Mar 2020 12:57:50 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.4.1 MIME-Version: 1.0 In-Reply-To: <81e2101e-d7ce-d023-5c35-ac6b55ea7166@linaro.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org >> Add new device as a child of the platform device, following the >> following hierarchy: >> >> platform_device >>      sdw_master_device >>          sdw_slave0 > > Why can't we just remove the platform device layer here and add > sdw_master_device directly? > > What is it stopping doing that? The guidance from Greg was "no platform devices, unless you really are on a platform bus (i.e. Device tree.)". We never discussed changing the way the Device Tree parts are handled. The main idea was to leave the parent (be it platform-device or PCI device) alone and not add new attributes or references to it. The scheme here is similar to I2C/SPI, you have a platform device handled by the Device Tree baseline, and a driver create an i2c_adapter/spi_controller/sdw_master_device.