Hi Mike, Stephen,
This patch series improves the accuracy of the CPU clock rate on R-Car
Gen3 SoCs, and adds support for CPU boost modes (marked "turbo-mode" in
the operating points table in DT).
As usual, it is preceded by a few small cleanups.
The easiest way to test this is by enabling
CONFIG_CPU_FREQ_DEFAULT_GOV_USERSPACE, and writing the requested clock
rate to /sys/devices/system/cpu/cpufreq/policy$n/scaling_setspeed
(n=0 for the first cluster, n=2 or 4 for the second cluster).
Note that you need to do
echo 1 > /sys/devices/system/cpu/cpufreq/boost
before you can enable boost modes.
The PLL rates and CPU clock rates and voltages can be monitored in
/sys/kernel/debug/{clk/{z,z2,.pll[024]}/clk_rate,reg*/dvfs/cpu*/*uV}.
The DVFS voltage measured by the on-board max9611 can be monitored
remotely using iio-monitor.
This series has been tested on Salvator-(X)S (with R-Car H3 ES1.0, H3
ES2.0, M3-W, and M3-N) and Ebisu-4D (R-Car E3).
As boost modes may be unstable without increasing the CPU core voltage,
this series depends on "[PATCH 0/2] arm64: dts: renesas: Add cpu-supply
properties for DVFS"[1]. Hence I think it is better to postpone this to
v5.14.
Thanks for your comments!
[1] https://lore.kernel.org/r/20210326105009.1574424-1-geert+renesas@xxxxxxxxx
Geert Uytterhoeven (7):
clk: renesas: rcar-gen3: Update Z clock rate formula in comments
clk: renesas: rcar-gen3: Make cpg_z_clk.mask u32
clk: renesas: rcar-gen3: Remove superfluous masking in
cpg_z_clk_set_rate()
clk: renesas: rcar-gen3: Grammar s/dependent of/dependent on/
clk: renesas: rcar-gen3: Increase Z clock accuracy
clk: renesas: rcar-gen3: Add custom clock for PLLs
clk: renesas: rcar-gen3: Add boost support to Z clocks
drivers/clk/renesas/rcar-gen3-cpg.c | 183 +++++++++++++++++++++++-----
1 file changed, 154 insertions(+), 29 deletions(-)
--
2.25.1
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
