From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mta0.migadu.com (out-224.mta0.migadu.com [91.218.175.224]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5DBEA38AC79 for ; Mon, 14 Sep 2026 18:29:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.224 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789410562; cv=none; b=gU3UQIiJy8g9A00grWyfZnjrExwg+B51u9QRlGHFHWkfWhWKFfiuEnbUHQZ/gyeI11hlNqpbW0j+16697I8H6rpXSjiT59rAh0DT0QYaMUSDv/UCs6k76PtbCNOIvWxjsa01F7a60c90qEJIQQAn/DZssGjTh/OnkEVfzl2tj7U= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789410562; c=relaxed/simple; bh=oiUF5LhxlHtYbTxjopkGNneVmugHN51Eq7CGGnZam7c=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=bgNMcfmP42jahT3708XppcoBq+xiKDnmXDG+2Ed66oEZFpp1zeS/PRl0uOGwvMVZlR70NHgA/0wZCgiG6IdNrFqXmn6a7VnZBqwyq85m/C6Dy4TbvG2X5AiZ+buJoxZ0IoyF8cCqDpFHjPeNymXZhVub//noEc4aevB7nIxTIg0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=Ejzlphn0; arc=none smtp.client-ip=91.218.175.224 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="Ejzlphn0" X-Envelope-To: linux-kernel@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=oiUF5LhxlHtYbTxjopkGNneVmugHN51Eq7CGGnZam7c=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1789410557; v=1; x=1790015357; b=Ejzlphn0Vu+wMB4ePv4GJDq8Ynn9cQqvSpCU10hF+uxC8F80TICdVTbCmo6KiSutmeBR4fI1 hocfncLt4Vl1ncC8qP1A+6CPpapeUB07ZBKFvbk54LI18nrO88VK9Tb5SxifhursPBzyf2G9+t3 s7xQxC8rGhmgUgO8HGQ+Mp4k= X-Envelope-To: linux-kernel@vger.kernel.org Received: by smtp.migadu.com with ESMTPS id 934f72edde8d4b3d; Mon, 14 Sep 2026 18:29:07 +0000 X-Mizu-Trace-ID: 934f72edde8d4b3d X-Migadu-Flow: FLOW_OUT Message-ID: <8c6bfa54-83a7-4d37-bbc8-d3384dfc6ce2@linux.dev> Date: Mon, 14 Sep 2026 19:21:32 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 2/3] soundwire: qcom: add multi-master support To: Srinivas Kandagatla , robh@kernel.org, vkoul@kernel.org Cc: krzk+dt@kernel.org, conor+dt@kernel.org, srini@kernel.org, yung-chuan.liao@linux.intel.com, prasad.kumpatla@oss.qualcomm.com, jingyi.wang@oss.qualcomm.com, sibi.sankar@oss.qualcomm.com, quic_srivasam@quicinc.com, linux-arm-msm@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-sound@vger.kernel.org References: <0097b59e2b96d692b9fb542e207ee43f9dd44a7f.1789114385.git.srinivas.kandagatla@oss.qualcomm.com> Content-Language: en-US From: Pierre-Louis Bossart In-Reply-To: <0097b59e2b96d692b9fb542e207ee43f9dd44a7f.1789114385.git.srinivas.kandagatla@oss.qualcomm.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 9/11/26 10:21, Srinivas Kandagatla wrote: > v3.1.0+ Qualcomm SoundWire IPs can be paired to expose one logical > bus with more than two DATA lanes. One IP owns SWR_CLK and drives > the bus; the other contributes DATA lanes only. > > Support this pairing on the driver side. A device link between the > two IPs enforces correct unbind ordering and keeps the peer resumed > while the primary is active. > > Single-master deployments (no qcom,multi-master-mode in DT) are > unaffected. It'd be good to clarify how the command protocol is handled. Each IP is probably capable of handling PING/READ/WRITE commands in Column0, but in the paired option the primary IP is the only one that deals with Column0 and all other DATA lanes are just data?