From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757329AbaCUOy7 (ORCPT ); Fri, 21 Mar 2014 10:54:59 -0400 Received: from top.free-electrons.com ([176.31.233.9]:57105 "EHLO mail.free-electrons.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751488AbaCUOy4 (ORCPT ); Fri, 21 Mar 2014 10:54:56 -0400 Date: Fri, 21 Mar 2014 15:54:03 +0100 From: Alexandre Belloni To: Sebastian Hesselbarth Cc: Mike Turquette , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Antoine =?iso-8859-1?Q?T=E9nart?= Subject: Re: [PATCH 3/5] ARM: berlin/dt: add cpupll and syspll support to BG2Q Message-ID: <20140321145403.GC6443@piout.net> References: <1395402220-23503-1-git-send-email-alexandre.belloni@free-electrons.com> <1395402220-23503-4-git-send-email-alexandre.belloni@free-electrons.com> <532C2C71.4010703@gmail.com> <20140321121741.GB6443@piout.net> <532C30AB.5020108@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <532C30AB.5020108@gmail.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 21/03/2014 at 13:29:31 +0100, Sebastian Hesselbarth wrote : > >>Hmm, you probably know better than me, but if cpuclk == cpupll > >>is always true we don't need another clk layer here. If you > >>can scale down cpuclk from cpupll and we just have no driver > >>for it, I am fine with it. > >> > > > >You can actually switch CPU clk from CPU pll to smclk. I'm not sure this > >is completely useful yet though, probably for suspend ? > > Then it should be clk mux instead? > > >Also, while I'm not sure this is a good reason, other clocks are derived > >from CPU pll and have another divider. > > I have no strong opinion, but a fixed-factor-clock with 1:1 just to > rename cpupll to cpuclk seems a bit wasty ;) > > If there is a mux, we should add it now - no matter if we are ever > going to make any use of it. For the derived clocks we should be > careful if they actually depend on cpuclk or always cpupll. > > If your (current) knowledge of the berlin clock trees is almost as > bad as mine, we can also ignore cpuclk mux if you prefer. > Yeah, fact is I know there is a mux but I don't know yet how to get/set its state so I will ignore it until we have more info. -- Alexandre Belloni, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com