Hi Simon, On Mon, Aug 21, 2017 at 3:01 PM, Simon Horman <horms+renesas@xxxxxxxxxxxx> wrote: > this patch-set adds Z and Z2 clock support. > > These are dependencies for supporting CPUFreq. The remainder of that > work is being posted separately and can be found at: > > https://git.kernel.org/pub/scm/linux/kernel/git/horms/renesas.git topic/rcar-gen3-cpufreq > > A description of steps taken to lightly exercise the same feature for the > r88a7795 the above can be found at the link below. The results are the same > for the r8a7796 with the exception that it has two active CPU cores rather > than four. > > http://elinux.org/Tests:R-CAR-GEN3-CPUFreq Thanks for your patches, and the wiki page! I gave it a try on R-Car H3 (ES1.0 and ES2.0) and M3-W (ES1.0), and the off-by-two factor of the Z clock frequency is gone. I couldn't test on R-Car H3 ES1.1. Probably it's OK, too (ES1.1 fixed the missing PLL0/2/4 post-divider in ES1.0). 1. After boot-up, the CPU clock frequency is 1.5 GHz, and /sys/devices/system/cpu/cpu*/cpufreq/scaling_cur_freq and /sys/kernel/debug/clk/z/clk_rate agree. Good. 2. After switching to the conservative governor, scaling_cur_freq reports either a 500 MHz or 1 GHz clock rate. But /sys/kernel/debug/clk/z/clk_rate disagrees: it reports either a 200 or 700 MHz clock rate. Ah, there's also cpuinfo_cur_freq. That value matches the Z clock. Interestingly, cpuinfo_cur_freq is lower than cpuinfo_min_freq? /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_cur_freq:200000 /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_max_freq:1500000 /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_min_freq:500000 3. After switching back to the performance governor, scaling_cur_freq reports 1.5 GHz again. But cpuinfo_cur_freq is still only 700 MHz, just like z/clk_rate. Do you know what's wrong? Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
