On Sat, 2013-03-16 at 03:38 +0800, Stephen Warren wrote: > On 03/15/2013 06:33 AM, Ulf Hansson wrote: > > On 15 March 2013 13:06, Bill Huang <bilhu...@nvidia.com> wrote: > >> On Fri, 2013-03-15 at 18:08 +0800, Ulf Hansson wrote: > ... > >>> Some prerequisites; I think am in favor of using the clk API to > >>> trigger DVFS changes and then I agree on that clk_prepare|unprepare > >>> needs to be possible to track from a DVFS perspective. clk_set_rate is > >>> not enough. > >>> > >>> So if we decide to do the above (using the clk API to trigger DVFS > >>> changes), I believe we should discuss two possible solutions; > >>> - clk notifiers or.. > >>> - dvfs clock type. > >>> > >>> I am trying to make up my mind of what I think is the best solution. > >>> Have you considered "dvfs clock type"? > >>> I put some comments about this for "[PATCH 2/5] clk: notifier handler > >>> for dynamic voltage scaling" recently as well. > >>> > >>> What could the advantages/disadvantages be between the two options? > >> > >> I personally prefer clk notifiers since that's easy and all the existing > >> device drivers don't need to be modified, a new clock or API might be > >> more thoroughly considered (and hence maybe more graceful) but that > >> means we need more time to cook and many drivers need to plug into that > >> API when it comes out, a lot of test/verification or maybe chaos > >> follows, I'm not sure will that be a little overkill. > > > > I guess you did not fully got what I meant with "dvfs clock type". It > > will not affect the clock API. But instead the dvfs is handled by > > implementing a specific clk hw type. So the same thing is accomplished > > as with clk notifiers, no changes should be needed to device drivers. > > > > The difference is only that no notifiers will be needed, and all the > > dvfs stuff will be handled in the clk hw instead. It will mean that we > > will bundle dvfs stuff into the clock drivers, instead of separating > > the code outside the clock drivers. But, on the other hand no > > notifiers will be needed. > > The advantage here is that I assume that a notifier would continually > have to check whether the clock being modified was one that the DVFS > notifier cared about. By integrating the CVFS logic into the clk_hw
Actually, we can register notifier only on clocks that DVFS care about. _______________________________________________ linaro-dev mailing list linaro-dev@lists.linaro.org http://lists.linaro.org/mailman/listinfo/linaro-dev