[PATCH 2/2] arm64: dts: mediatek: cherry: Add CPU supply dependency to cpufreq-hw

From: Nícolas F. R. A. Prado
Date: Fri Dec 29 2023 - 16:31:35 EST


When the mediatek-cpufreq-hw driver enables the hardware (by
writing to REG_FREQ_ENABLE), if the regulator supplying the voltage to
the big CPUs hasn't probed yet, the platform hangs shortly after and
"rcu: INFO: rcu_preempt detected stalls on CPUs/tasks" are printed in
the log.

To prevent this from happening, describe the big CPUs regulator in the
performance-controller DT node, so that devlink ensures the regulator
has been probed and configured before the frequency scaling hardware is
probed and enabled.

Signed-off-by: Nícolas F. R. A. Prado <nfraprado@xxxxxxxxxxxxx>

---

arch/arm64/boot/dts/mediatek/mt8195-cherry.dtsi | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/arch/arm64/boot/dts/mediatek/mt8195-cherry.dtsi b/arch/arm64/boot/dts/mediatek/mt8195-cherry.dtsi
index dd5b89b73190..505da60eee90 100644
--- a/arch/arm64/boot/dts/mediatek/mt8195-cherry.dtsi
+++ b/arch/arm64/boot/dts/mediatek/mt8195-cherry.dtsi
@@ -502,6 +502,10 @@ &pcie1 {
pinctrl-0 = <&pcie1_pins_default>;
};

+&performance {
+ big-cpus-supply = <&mt6315_6_vbuck1>;
+};
+
&pio {
mediatek,rsel-resistance-in-si-unit;
pinctrl-names = "default";
--
2.43.0