Quoting Viresh Kumar (2015-03-05 00:59:50) > On 5 March 2015 at 13:12, Sascha Hauer <s.ha...@pengutronix.de> wrote: > > We have clk_set_parent for changing the parent and clk_set_rate to > > change the rate. Use the former for changing the parent and the latter > > for changing the rate. What you are interested in is changing the > > parent, so use clk_set_parent for this and not abuse a side effect > > of clk_set_rate. > > clk_set_rate() for CPUs clock is responsible to change clock rate > of the CPU. Whether it plays with PLLs or muxes, its not that relevant.
Agreed. > > > My suggestion is to take another approach. Implement clk_set_rate for > > these muxes and in the set_rate hook: > > > > - switch mux to intermediate PLL parent > > - call clk_set_rate() for the real parent PLL > > - switch mux back to real parent PLL > > > > This way the things happening behind the scenes are completely transparent > > to the cpufreq driver and you can use cpufreq-dt as is without changes. > > CPUFreq wants to change to intermediate frequency by itself against > some magic change behind the scene. The major requirement for that > comes from the fact that we want to send PRE/POST freq notifiers on > which loops-per-jiffie depends. I assume you are saying that you want to update loops-per-jiffie while at an intermediate frequency. Why? This operation should not take very long. Imagine a (hypothetical?) processor that changes frequency in many small steps until it converges to the target rate. Would you want to update lpj for every step? Regards, Mike -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
