From mboxrd@z Thu Jan 1 00:00:00 1970 From: Richard Zhao Subject: Re: [PATCH v4 4/7] cpufreq: add clk-reg cpufreq driver Date: Mon, 26 Dec 2011 21:44:52 +0800 Message-ID: <20111226134449.GA4259@richard-laptop> References: <1324537753-30590-1-git-send-email-richard.zhao@linaro.org> <1324537753-30590-5-git-send-email-richard.zhao@linaro.org> <20111223131851.GB13175@sirena.org.uk> <20111224085539.GA1892@richard-laptop> <20111224122411.GA13778@sirena.org.uk> <20111224132831.GB1803@richard-laptop> <20111224134227.GA20908@opensource.wolfsonmicro.com> <20111224155227.GC1803@richard-laptop> <20111226111030.GC8722@opensource.wolfsonmicro.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <20111226111030.GC8722-yzvPICuk2AATkU/dhu1WVueM+bqZidxxQQ4Iyu8u01E@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linaro-dev-bounces-cunTk1MwBs8s++Sfvej+rw@public.gmane.org Errors-To: linaro-dev-bounces-cunTk1MwBs8s++Sfvej+rw@public.gmane.org To: Mark Brown Cc: davej-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, linaro-dev-cunTk1MwBs8s++Sfvej+rw@public.gmane.org, arnd-r2nGTMty4D4@public.gmane.org, patches-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org, marc.zyngier-5wv7dgnIgG8@public.gmane.org, catalin.marinas-5wv7dgnIgG8@public.gmane.org, devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org, rdunlap-/UHa2rfvQTnk1uMJSBkQmQ@public.gmane.org, cpufreq-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, eric.miao-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org, kernel-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org, jamie-wmLquQDDieKakBO8gow8eQ@public.gmane.org, linux-lFZ/pmaqli7XmaaqVzeoHQ@public.gmane.org, rob.herring-bsGFqQB8/DxBDgjK7y7TUQ@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org List-Id: devicetree@vger.kernel.org On Mon, Dec 26, 2011 at 11:10:30AM +0000, Mark Brown wrote: > On Sat, Dec 24, 2011 at 11:52:29PM +0800, Richard Zhao wrote: > > On Sat, Dec 24, 2011 at 01:42:29PM +0000, Mark Brown wrote: > > > On Sat, Dec 24, 2011 at 09:28:33PM +0800, Richard Zhao wrote: > > > > > If you think regulator thansition latency is board specific, then the board > > > > dts can overrite it. > > > > We should just query this information from the regulator subsystem > > > (there's hooks but currently nothing implements them). The regulators > > > can define their own bindings if they need to read it from device tree, > > > most of them should be able to do this as a function of knowing about > > > the device. None of this is specific to cpufreq so cpufreq shouldn't > > > have to define its own support for this. > > > I'd like to query the latency by call clk and regulator APIs. but as you said > > both of them have not implemented it yet. I think, for now, we can use the > > The *call* is there in the regulator subsystem, it's just that none of > the drivers back it up with an actual implementation yet. Which turns > out to be a good thing as cpufreq can't currently understand variable > latencies and the governors don't deal well with non-trivial latencies > anyway. but clk API don't have such calls. and many SoCs only adjust clk frequencies, using one single voltage. > > > property to get the total latency. Once I can get it at runtime, I'll remove > > it. So the definition of trans-latency is just the same as cpufreq transition_latency, > > people get less confused. What do you think? > > The problem with device tree is that once you've defined a binding > you're stuck with it, it's very hard to change - witness all the magic > number based stuff with the interrupt bindings for example So what's your suggestion? We can not set transition_latency to set random number. Thanks Richard