From mboxrd@z Thu Jan 1 00:00:00 1970 From: Olof Johansson Subject: Re: [PATCH] cpufreq: ARM big LITTLE: Add generic cpufreq driver and its DT glue Date: Wed, 6 Mar 2013 17:46:57 -0800 Message-ID: <20130307014657.GA7426@quad.lixom.net> References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mail-da0-f52.google.com ([209.85.210.52]:32864 "EHLO mail-da0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758597Ab3CGBqn (ORCPT ); Wed, 6 Mar 2013 20:46:43 -0500 Received: by mail-da0-f52.google.com with SMTP id f10so38893dak.25 for ; Wed, 06 Mar 2013 17:46:42 -0800 (PST) Content-Disposition: inline In-Reply-To: Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: Viresh Kumar Cc: rjw@sisk.pl, cpufreq@vger.kernel.org, linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, robin.randhawa@arm.com, Steve.Bannister@arm.com, Liviu.Dudau@arm.com, charles.garcia-tobin@arm.com, linaro-kernel@lists.linaro.org, mark.hambleton@broadcom.com, linux-arm-kernel@lists.infradead.org, Sudeep KarkadaNagesha On Tue, Mar 05, 2013 at 12:52:41PM +0800, Viresh Kumar wrote: > +++ b/Documentation/devicetree/bindings/cpufreq/arm_big_little_dt.txt > @@ -0,0 +1,29 @@ > +Generic ARM big LITTLE cpufreq driver's DT glue > +----------------------------------------------- > + > +It is DT specific glue layer for generic cpufreq driver for big LITTLE systems. > + > +Both required and optional properties listed below must be defined under node > +cluster*. * can be 0 or 1. > + > +Required properties: > +- freqs: List of all supported frequencies. > + > +Optional properties: > +- clock-latency: Specify the possible maximum transition latency for clock, in > + unit of nanoseconds. > + > +Examples: > + > +cluster0: cluster@0 { > + .. > + > + freqs = <500000000 600000000 700000000 800000000 900000000 1000000000 1100000000 1200000000>; > + clock-latency = <200000>; > + > + .. > + > + cores { > + .. > + }; > +}; This binding makes no sense to me. It needs to be substantially better documented, not just a couple of sentences that people that understand bit.LITTLE thoroughly can make sense of. It also duplicates the cpu binding. I suspect this should instead be done through additions of the cpu bindings instead of duplication. So this needs to be substantially reworked. -Olof