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 3B668C43603 for ; Wed, 18 Dec 2019 09:53:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 17EDA20717 for ; Wed, 18 Dec 2019 09:53:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726551AbfLRJxF (ORCPT ); Wed, 18 Dec 2019 04:53:05 -0500 Received: from mail.bugwerft.de ([46.23.86.59]:46500 "EHLO mail.bugwerft.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725799AbfLRJxF (ORCPT ); Wed, 18 Dec 2019 04:53:05 -0500 Received: from [10.10.222.226] (unknown [194.162.236.226]) by mail.bugwerft.de (Postfix) with ESMTPSA id 3A811281DF4; Wed, 18 Dec 2019 09:46:38 +0000 (UTC) Subject: Re: [alsa-devel] [PATCH 00/10] mfd: Add support for Analog Devices A2B transceiver To: Pierre-Louis Bossart , linux-kernel@vger.kernel.org, linux-gpio@vger.kernel.org, linux-i2c@vger.kernel.org, alsa-devel@alsa-project.org, devicetree@vger.kernel.org, linux-clk@vger.kernel.org Cc: lars@metafoo.de, sboyd@kernel.org, mturquette@baylibre.com, robh+dt@kernel.org, broonie@kernel.org, pascal.huerst@gmail.com, lee.jones@linaro.org References: <20191209183511.3576038-1-daniel@zonque.org> From: Daniel Mack Message-ID: <22803ea0-0c4a-b096-ec11-5e8f5c27d8d3@zonque.org> Date: Wed, 18 Dec 2019 10:53:02 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.2.2 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-clk-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-clk@vger.kernel.org Hi, On 12/17/19 8:29 PM, Pierre-Louis Bossart wrote: >> Transceivers can both receive and provide audio, and streams can be >> routed from one node to any other, including many others. The tricky >> bit is how to expose the audio routing in DT in a sane way. >> The way it is implemented here, the slave nodes specify the number of >> slots they each consume and generate, and which thereof they forward >> from one side to the other. This mimics the internal register >> structure and should allow for even exotic setups. > > It was my understanding that the A2B bus is bidirectional but with > separate time windows allocated for host->device and device->host > transmission. The wording seems to hint at device-to-device > communication but I wonder if this is really what you meant. Yes, audio frames can be exchanged between two slave nodes without interaction by the master node. I'm not sure what the best way is to describe that in DT really, but as the hardware is capable of doing it, there must be a way to enable such setups. Thanks, Daniel