Hi Uwe, On Thu, 2014-05-15 at 09:47AM +0200, Uwe Kleine-König wrote: > On Wed, May 14, 2014 at 03:30:50PM -0700, Soren Brinkmann wrote: > > Hi, > > > > I have one or two problems with cpufreq and the CCF, which are caused by > > rounding/different frequency resolutions. > > > > cpufreq works with kHz, while the CCF uses Hz. On Zynq our default frequency is > > 666666666 Hz which the CCF, due to rounding, reports as 666666660. And for > Why does this happen? Isn't that a bug? What is the actual freqency? > 666666666 Hz or 2000000000/3 Hz? I don't know for sure. I think it's rounding that takes place in the CCF. That output clock goes from a x-tal through an PLL and various muxes and dividers. I guess some inaccuracies in the magnitude of a few Hz are probably not avoidable in that processing chain. > > > cpufreq, which simply divides values it obtains through clk_round_rate() by > > 1000, 666666. > > Since passing 666666 to clk_round_rate() does not result in 666666660 > > (clk_round_rate() always rounds down!), we chose to put 666667 in the OPP. This > What is OPP? As Nishanth already said, Operating Performance Points. Sorry for being lazy and not having spelled that out. Sören -- 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
