From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751925AbdCAHuk (ORCPT ); Wed, 1 Mar 2017 02:50:40 -0500 Received: from smtp.codeaurora.org ([198.145.29.96]:60942 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751009AbdCAHug (ORCPT ); Wed, 1 Mar 2017 02:50:36 -0500 DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 07F4E60D62 Authentication-Results: pdx-caf-mail.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: pdx-caf-mail.web.codeaurora.org; spf=none smtp.mailfrom=rnayak@codeaurora.org Message-ID: <58B669DD.5010309@codeaurora.org> Date: Wed, 01 Mar 2017 11:57:41 +0530 From: Rajendra Nayak User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.0 MIME-Version: 1.0 To: Rob Herring , Ulf Hansson CC: Viresh Kumar , Rafael Wysocki , Kevin Hilman , Viresh Kumar , Nishanth Menon , Stephen Boyd , "linaro-kernel@lists.linaro.org" , "linux-pm@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Vincent Guittot , Lina Iyer , "devicetree@vger.kernel.org" , Jon Hunter Subject: Re: [PATCH V3 2/7] PM / OPP: Introduce "domain-performance-state" binding to OPP nodes References: <20170228003948.ihf4c2ppu2rf3lt2@rob-hp-laptop> <20170228065711.GD19417@vireshk-i7> In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 02/28/2017 09:22 PM, Rob Herring wrote: > On Tue, Feb 28, 2017 at 9:14 AM, Ulf Hansson wrote: >> [...] >> >>>> ---> Parent domain-2 (Contains Perfomance states) >>>> | >>>> | >>>> C.) DeviceX ---> Parent-domain-1 | >>>> | >>>> | >>>> ---> Parent domain-3 (Contains Perfomance states) >>> >>> I'm a bit confused. How does a domain have 2 parent domains? >> >> This comes from the early design of the generic PM domain, thus I >> assume we have some HW with such complex PM topology. However, I don't >> know if it is actually being used. >> >> Moreover, the corresponding DT bindings for "power-domains" parents, >> can easily be extended to cover more than one parent. See more in >> Documentation/devicetree/bindings/power/power_domain.txt > > I could easily see device having 2 power domains. For example a cpu > may have separate domains for RAM/caches and logic. And nesting of yet the bindings for power-domains (for consumer devices) only allows for one powerdomain to be associated with a device. > power domains is certainly common, but a power domain being contained > in 2 different parents? I don't even see how that is possible in the > physical design. Now if we're mixing PM and power domains again and > the cpu device is pointing to the cpu PM domain which contains 2 power > domains, then certainly that is possible. > > Rob > -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation