From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 To: Jisheng Zhang , "Stephen Boyd" , linux-clk@vger.kernel.org, linux-arm-kernel@lists.infradead.org, "Sebastian Hesselbarth" From: Michael Turquette In-Reply-To: <20160309152420.20de187a@xhacker> Cc: pi-cheng.chen@linaro.org References: <20160309152420.20de187a@xhacker> Message-ID: <20160311165152.4103.82090@quark.deferred.io> Subject: Re: [Query]set clk rate must operate its coordinated clock Date: Fri, 11 Mar 2016 08:51:52 -0800 List-ID: Jisheng, Quoting Jisheng Zhang (2016-03-08 23:24:20) > Dear Stephen, Michael, Sebastian and all, = > = > I have the following clk case which I dunno the elegant solution: > = > = > cpuclk have two parents: cpupll and refclk. When set the cpuclk freq, we > have to set its parent's freq, I.E cpupll freq. But before changing the > cpupll's freq, we should set its refclk as its parent firstly. > = > AFAIK, this is a common case, I have seen such requirement in rockchip, s= amsung > clk driver. They solve this by notifier, but as pointed out by Michael > in http://lists.infradead.org/pipermail/linux-arm-kernel/2015-June/351565= .html > = > "This is also a hack and it points towards some missing infrastructure in= the > clock framework." > = > I also don't like the notifier solution, I believe the elegant solution c= ould > be using the coordinated clock infrastructure. So what's the status of > this infrastructure? I can test, and I can even add some code to make it = be > ready to be merged if you guide me ;) Thanks for the email. I hope to finish that feature before ELC. I have Cc'd Pi-Cheng Chen from Mediatek who is also interested in coordinated clock rates. Regards, Mike > = > Thanks in advance, > Jisheng