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=-2.4 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,T_DKIMWL_WL_HIGH, USER_AGENT_MUTT autolearn=ham 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 92D49C04A6B for ; Wed, 8 May 2019 19:52:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5B17F21734 for ; Wed, 8 May 2019 19:52:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1557345164; bh=WvqlE0zoyG0HaDjphQsaFq6mRxNdKTiq1F02ec0+6Bo=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=bIZpPWG1JUXVVSPKzqttOQQFcb6FT5SsEDkbLxm86KpCFPVo/eNZnVztZ0caFW4Db m4BbzQ1mB1uV6gZ89o1EChBkolWc+/cpOdCzul01m47Gcby/P1I5gQsUv+ERg3agp0 QwFN7Q+2Mk5xn/7uKSCzYq1xJbiYW57Xc0Qnyt8Y= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728396AbfEHTwn (ORCPT ); Wed, 8 May 2019 15:52:43 -0400 Received: from mail.kernel.org ([198.145.29.99]:51160 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726852AbfEHTwn (ORCPT ); Wed, 8 May 2019 15:52:43 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 389EC214AF; Wed, 8 May 2019 19:52:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1557345161; bh=WvqlE0zoyG0HaDjphQsaFq6mRxNdKTiq1F02ec0+6Bo=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=rmfX5vc3on/JzT6wUcFitavY0RbtRsD+JW/PFXruSyUpQmR07wgSrqVDy6GaoSa/F pFtRYcbBqQgrIni09uMAjm/TAa5viZhb4GBCgTjtFi6S5/nyxhv/n88lXjXuFVEns7 V3lpZWZvYKJu2emVGDK049Uw1XD8Q1tb7UeYtFcM= Date: Wed, 8 May 2019 18:59:45 +0200 From: Greg KH To: Pierre-Louis Bossart Cc: Vinod Koul , alsa-devel@alsa-project.org, tiwai@suse.de, linux-kernel@vger.kernel.org, liam.r.girdwood@linux.intel.com, broonie@kernel.org, srinivas.kandagatla@linaro.org, jank@cadence.com, joe@perches.com, Sanyog Kale Subject: Re: [alsa-devel] [RFC PATCH 1/7] soundwire: Add sysfs support for master(s) Message-ID: <20190508165945.GC6157@kroah.com> References: <20190504065242.GA9770@kroah.com> <20190507052732.GD16052@vkoul-mobl> <20190507055432.GB17986@kroah.com> <20190507110331.GL16052@vkoul-mobl> <20190507111956.GB1092@kroah.com> <10fef156-7b01-7a08-77b4-ae3153eaaabc@linux.intel.com> <20190508074606.GV16052@vkoul-mobl> <20190508091628.GB1858@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.11.4 (2019-03-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, May 08, 2019 at 11:42:15AM -0500, Pierre-Louis Bossart wrote: > > > On 5/8/19 4:16 AM, Greg KH wrote: > > On Wed, May 08, 2019 at 01:16:06PM +0530, Vinod Koul wrote: > > > On 07-05-19, 17:49, Pierre-Louis Bossart wrote: > > > > > > > > > > The model here is that Master device is PCI or Platform device and then > > > > > > creates a bus instance which has soundwire slave devices. > > > > > > > > > > > > So for any attribute on Master device (which has properties as well and > > > > > > representation in sysfs), device specfic struct (PCI/platfrom doesn't > > > > > > help). For slave that is not a problem as sdw_slave structure takes care > > > > > > if that. > > > > > > > > > > > > So, the solution was to create the psedo sdw_master device for the > > > > > > representation and have device-specific structure. > > > > > > > > > > Ok, much like the "USB host controller" type device. That's fine, make > > > > > such a device, add it to your bus, and set the type correctly. And keep > > > > > a pointer to that structure in your device-specific structure if you > > > > > really need to get to anything in it. > > > > > > > > humm, you lost me on the last sentence. Did you mean using > > > > set_drv/platform_data during the init and retrieving the bus information > > > > with get_drv/platform_data as needed later? Or something else I badly need > > > > to learn? > > > > > > IIUC Greg meant we should represent a soundwire master device type and > > > use that here. Just like we have soundwire slave device type. Something > > > like: > > > > > > struct sdw_master { > > > struct device dev; > > > struct sdw_master_prop *prop; > > > ... > > > }; > > > > > > In show function you get master from dev (container of) and then use > > > that to access the master properties. So int.sdw.0 can be of this type. > > > > Yes, you need to represent the master device type if you are going to be > > having an internal representation of it. > > Humm, confused...In the existing code bus and master are synonyms, see e.g. > following code excerpts: > > * sdw_add_bus_master() - add a bus Master instance > * @bus: bus instance > * > * Initializes the bus instance, read properties and create child > * devices. > > struct sdw_bus { > struct device *dev; <<< pointer here That's the pointer to what? The device that the bus is "attached to" (i.e. parent, like a platform device or a pci device)? Why isn't this a "real" device in itself? I thought I asked that a long time ago when first reviewing these patches... > unsigned int link_id; > struct list_head slaves; > DECLARE_BITMAP(assigned, SDW_MAX_DEVICES); > struct mutex bus_lock; > struct mutex msg_lock; > const struct sdw_master_ops *ops; > const struct sdw_master_port_ops *port_ops; > struct sdw_bus_params params; > struct sdw_master_prop prop; > > The existing code creates a platform_device in > drivers/soundwire/intel_init.c, and it's assigned by the following code: The core creates a platform device, don't assume you can "take it over" :) That platform device lives on the platform bus, you need a "master" device that lives on your soundbus bus. Again, look at how USB does this. Or better yet, greybus, as that code is a lot smaller and simpler. > > static int intel_probe(struct platform_device *pdev) > { > struct sdw_cdns_stream_config config; > struct sdw_intel *sdw; > int ret; > > sdw = devm_kzalloc(&pdev->dev, sizeof(*sdw), GFP_KERNEL); > [snip] > sdw->cdns.dev = &pdev->dev; > sdw->cdns.bus.dev = &pdev->dev; Gotta love the lack of reference counting :( > I really don't see what you are hinting at, sorry, unless we are talking > about major surgery in the code. It sounds like you need a device on your bus that represents the master, as you have attributes associated with it, and other things. You can't put attributes on a random pci or platform device, as you do not "own" that device. does that help? greg k-h