Re: [RFC/RFT v2 12/14] arm64: dts: meson-g12a: enable DVFS on G12A boards
From: Kevin Hilman <khilman@baylibre.com>
Date: 2019-06-28 18:08:26
Also in:
linux-amlogic, linux-clk, linux-gpio, lkml
Neil Armstrong [off-list ref] writes:
Enable DVFS for the U200, SEI520 and X96-Max Amlogic G12A based board by setting the clock, OPP and supply for each CPU cores. The CPU cluster power supply can achieve 0.73V to 1.01V using a PWM output clocked at 800KHz with an inverse duty-cycle. DVFS has been tested by running the arm64 cpuburn at [1] and cycling between all the possible cpufreq translations and checking the final frequency using the clock-measurer, script at [2]. [1] https://github.com/ssvb/cpuburn-arm/blob/master/cpuburn-a53.S [2] https://gist.github.com/superna9999/d4de964dbc0f84b7d527e1df2ddea25f Signed-off-by: Neil Armstrong <redacted>
[...]
quoted hunk ↗ jump to hunk
@@ -297,6 +316,34 @@ status = "okay"; }; +&cpu0 { + cpu-supply = <&vddcpu>; + operating-points-v2 = <&cpu_opp_table>; + clocks = <&clkc CLKID_CPU_CLK>; + clock-latency = <50000>; +}; + +&cpu1 { + cpu-supply = <&vddcpu>; + operating-points-v2 = <&cpu_opp_table>; + clocks = <&clkc CLKID_CPU_CLK>; + clock-latency = <50000>; +}; + +&cpu2 { + cpu-supply = <&vddcpu>; + operating-points-v2 = <&cpu_opp_table>; + clocks = <&clkc CLKID_CPU_CLK>; + clock-latency = <50000>; +}; + +&cpu3 { + cpu-supply = <&vddcpu>; + operating-points-v2 = <&cpu_opp_table>; + clocks = <&clkc CLKID_CPU_CLK>; + clock-latency = <50000>; +};
Just curious where this max clock transtion (clock-latency) value came from. Were you able to measure that somehow? Kevin _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel