From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752450AbdB1QES (ORCPT ); Tue, 28 Feb 2017 11:04:18 -0500 Received: from mail.kernel.org ([198.145.29.136]:34268 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751677AbdB1QEQ (ORCPT ); Tue, 28 Feb 2017 11:04:16 -0500 MIME-Version: 1.0 In-Reply-To: References: <20170228003948.ihf4c2ppu2rf3lt2@rob-hp-laptop> <20170228065711.GD19417@vireshk-i7> From: Rob Herring Date: Tue, 28 Feb 2017 09:52:05 -0600 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH V3 2/7] PM / OPP: Introduce "domain-performance-state" binding to OPP nodes To: 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 , Rajendra Nayak , "devicetree@vger.kernel.org" Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 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 From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rob Herring Subject: Re: [PATCH V3 2/7] PM / OPP: Introduce "domain-performance-state" binding to OPP nodes Date: Tue, 28 Feb 2017 09:52:05 -0600 Message-ID: References: <20170228003948.ihf4c2ppu2rf3lt2@rob-hp-laptop> <20170228065711.GD19417@vireshk-i7> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Return-path: In-Reply-To: Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Ulf Hansson Cc: Viresh Kumar , Rafael Wysocki , Kevin Hilman , Viresh Kumar , Nishanth Menon , Stephen Boyd , "linaro-kernel-cunTk1MwBs8s++Sfvej+rw@public.gmane.org" , "linux-pm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , Vincent Guittot , Lina Iyer , Rajendra Nayak , "devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" List-Id: devicetree@vger.kernel.org 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 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 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html