From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755729AbbCFQHJ (ORCPT ); Fri, 6 Mar 2015 11:07:09 -0500 Received: from smtp.codeaurora.org ([198.145.29.96]:40889 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753734AbbCFQHH convert rfc822-to-8bit (ORCPT ); Fri, 6 Mar 2015 11:07:07 -0500 Content-Type: text/plain; charset=windows-1252 Mime-Version: 1.0 (Mac OS X Mail 7.3 \(1878.6\)) Subject: Re: [Patch V7 02/10] ASoC: qcom: Document LPASS CPU bindings From: Kumar Gala In-Reply-To: <20150306015131.GA15850@kwestfie-linux.qualcomm.com> Date: Fri, 6 Mar 2015 10:07:01 -0600 Cc: Mark Brown , Takashi Iwai , Liam Girdwood , Banajit Goswami , Patrick Lai , David Brown , Bryan Huntsman , Greg KH , ALSA Mailing List , MSM Mailing List , Device Tree Mailing List , Kernel Mailing List Content-Transfer-Encoding: 8BIT Message-Id: References: <1425428519-12224-1-git-send-email-kwestfie@codeaurora.org> <1425428519-12224-3-git-send-email-kwestfie@codeaurora.org> <7E5AFC65-1705-4BDC-B57F-0444E83A8987@codeaurora.org> <20150306015131.GA15850@kwestfie-linux.qualcomm.com> To: Kenneth Westfield X-Mailer: Apple Mail (2.1878.6) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mar 5, 2015, at 7:51 PM, Kenneth Westfield wrote: > On Thu, Mar 05, 2015 at 12:52:30PM -0600, Kumar Gala wrote: >> >> On Mar 3, 2015, at 6:21 PM, Kenneth Westfield wrote: >> >>> +++ b/Documentation/devicetree/bindings/sound/qcom,lpass-cpu.txt >>> @@ -0,0 +1,49 @@ >>> +* Qualcomm Technologies LPASS CPU DAI >>> + >>> +Required subnodes: >>> + >>> +- qcom,adsp : Audio DSP sub-node >>> + >>> +Optional Audio DSP subnode properties: >>> + >>> +- status : "disabled" indicates the adsp is not available. >>> + >> >> What is the intent of this subnode? >> > > From the cover letter: > Even though the ipq806x LPASS does not contain an audio DSP, other SOCs > do have one. For those SOCs, the audio DSP typically controls the > hardware blocks in the LPASS. Hence, different CPU DAI driver(s) would > need to be used in order to facilitate audio with the DSP. As such, the > LPASS DT contains an adsp subnode, which is disabled for this SOC. The > same subnode should be enabled and populated for other SOCs that do > contain an audio DSP. Not using the audio DSP would require different > CPU DAI driver(s), in addition to possible bootloader and/or firmware > changes. > > This was the result of a request from Mark. See here: > http://thread.gmane.org/gmane.linux.drivers.devicetree/109331/focus=11633 Two quick comments before I read Mark’s comments. 1. Its not normal practice to put something into a DT that does not exist. Having a node, but marking it disabled implies existence. 2. How would one normally address the audio DSP if it did exist. I’m just wondering if having a subnode is the proper solution vs maybe a phandle - k -- Qualcomm Innovation Center, Inc. The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project