Quoting Bill Huang (2013-03-19 19:55:49) > On Wed, 2013-03-20 at 01:01 +0800, Mike Turquette wrote: > > Quoting Bill Huang (2013-03-19 06:28:32) > > > Add notifier calls in clk_prepare and clk_unprepare so drivers which are > > > interested in knowing that clk_prepare/unprepare call can act accordingly. > > > > > > The existing "clk_set_rate" notifier is not enough for normal DVFS > > > inplementation since clock might be enabled/disabled at runtime. Adding > > > these notifiers is useful on DVFS core which take clk_prepare as a hint > > > on that the notified clock might be enabled later so it can raise voltage > > > to a safe level before enabling the clock, and take clk_unprepare as a > > > hint that the clock has been disabled and is safe to lower the voltage. > > > > > > The added notifier events are: > > > > > > PRE_CLK_PREPARE > > > POST_CLK_PREPARE > > > ABORT_CLK_PREPARE > > > PRE_CLK_UNPREPARE > > > POST_CLK_UNPREPARE > > > > > > Signed-off-by: Bill Huang <bilhu...@nvidia.com> > > > > I'm still not sure about this approach. Based on feedback I got from > > Linaro Connect I am not convinced that scaling voltage through clk > > rate-change notifiers is the right way to go. As I understand it this > > patch only exists for that single purpose, so if the voltage-notifier > > idea gets dropped then I will not take this patch in. > > > Thanks Mike, actually we won't use your "clk: notifier handler for > dynamic voltage scaling" patch instead we are trying to port our DVFS > into Non-CPU DVFS framework "devfreq" which will need to hook those > notifiers, without the clock notifiers been extended the framework is > useless for us since we cannot do polling due to the fact that polling > is not in real time. If it ended up extending the notifiers cannot > happen then the only choice for us I think would be giving up "devfreq" > and implement them in Tegra's "clk_hw".
I'm familiar with the devfreq framework. Can you explain further how you plan to use devfreq with the clock notifiers? What does the call graph look like? Thanks, Mike _______________________________________________ linaro-dev mailing list linaro-dev@lists.linaro.org http://lists.linaro.org/mailman/listinfo/linaro-dev
