Hi Viresh On Fri, 8 Mar 2013, Viresh Kumar wrote: > On 8 March 2013 05:56, Guennadi Liakhovetski <g.liakhovetski@xxxxxx> wrote: > > I like generic drivers :) > > Me too :) > > > cpufreq-cpu0 is yet another such generic > > (cpufreq) driver. Now, comparing the functionality of the two: > > Great!! > > > we see, that this driver "only" switches CPU clock frequencies. Whereas > > the cpufreq-cpu0 driver also manipulates a regulator (if available) > > directly. I understand, power-saving is also an important consideration > > for big.LITTLE systems. So, I presume, you plan to implement voltage > > switching in cpufreq notifiers? > > So the platform on which we are currently testing these is ARM TC2 Soc > and this switching is done by the firmware instead. And so didn't went > for regulator hookups initially.. Obviously in future regulator hookups would > find some space in this driver but not required for now. > > > Now, my question is: is this (notifier) > > actually the preferred method and the cpufreq-cpu0 driver is doing it > > "wrongly?" > > What notifiers are you talking about? I believe using the regulator framework > is the right way of doing this. And that would be part of this code later on. Also in your driver you're doing cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE); ... cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE); So, theoretically you could install such notifiers to adjust CPU voltages (using regulators too). But adding regulator calls directly to the driver would make it consistent with cpufreq-cpu0.c, so, if this doesn't violate any concepts, I think, it would be good to add those when suitable systems appear. Thanks Guennadi --- Guennadi Liakhovetski, Ph.D. Freelance Open-Source Software Developer http://www.open-technology.de/ -- To unsubscribe from this list: send the line "unsubscribe cpufreq" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
