linux-kernel - Re: [RFC/RFT v3 14/14] arm64: dts: meson-g12b-odroid-n2: enable DVFS

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Date:   Wed, 3 Jul 2019 01:45:55 +0200
From:   Martin Blumenstingl <martin.blumenstingl@...glemail.com>
To:     Neil Armstrong <narmstrong@...libre.com>
Cc:     jbrunet@...libre.com, khilman@...libre.com,
        linux-arm-kernel@...ts.infradead.org,
        linux-amlogic@...ts.infradead.org, linux-kernel@...r.kernel.org,
        linux-clk@...r.kernel.org, linux-gpio@...r.kernel.org
Subject: Re: [RFC/RFT v3 14/14] arm64: dts: meson-g12b-odroid-n2: enable DVFS

On Mon, Jul 1, 2019 at 11:13 AM Neil Armstrong <narmstrong@...libre.com> wrote:
>
> Enable DVFS for the Odroid-N2 by setting the clock, OPP and supply
> for each cores of each CPU clusters.
>
> The first cluster uses the "VDDCPU_B" power supply, and the second
> cluster uses the "VDDCPU_A" power supply.
>
> Each power supply can achieve 0.73V to 1.01V using 2 distinct PWM
> outputs 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 of each cluster 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 <narmstrong@...libre.com>
Reviewed-by: Martin Blumenstingl <martin.blumenstingl@...glemail.com>

[...]
> +       vddcpu_b: regulator-vddcpu-b {
> +               /*
> +                * Silergy SY8120B1ABC Regulator.
> +                */
interesting that they use different regulator ICs for CPU A and CPU B
the public schematics confirm your comments