Re: [PATCH 1/2] arm64: dts: allwinner: h6: Add GPU OPP table to all boards

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] arm64: dts: allwinner: h6: missing regulator-ramp-delay on reg_dcdcc
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commit ba32fa6c0b22c915eb543aebaebb44bdfbbd45e8
Author: Jernej Skrabec <jernej.skrabec@gmail.com>

arm64: dts: allwinner: h6: Add GPU OPP table to all boards

This commit includes sun50i-h6-gpu-opp.dtsi across the remaining Allwinner
H6 board device trees so that devfreq can scale the GPU clock rate and
voltage.

> diff --git a/arch/arm64/boot/dts/allwinner/sun50i-h6-orangepi.dtsi b/arch/arm64/boot/dts/allwinner/sun50i-h6-orangepi.dtsi
> index e34dbb9920216..2948369cd659b 100644
> --- a/arch/arm64/boot/dts/allwinner/sun50i-h6-orangepi.dtsi
> +++ b/arch/arm64/boot/dts/allwinner/sun50i-h6-orangepi.dtsi
> @@ -5,6 +5,7 @@
>  /dts-v1/;
>  
>  #include "sun50i-h6.dtsi"
> +#include "sun50i-h6-gpu-opp.dtsi"

[Severity: Medium]
Should reg_dcdcc in sun50i-h6-orangepi.dtsi also specify
regulator-ramp-delay = <2500> when enabling the GPU OPP table here?

In arch/arm64/boot/dts/allwinner/sun50i-h6-orangepi.dtsi, &gpu uses
mali-supply = <&reg_dcdcc>, which is currently defined without a ramp delay:

	reg_dcdcc: dcdcc {
		regulator-enable-ramp-delay = <32000>;
		regulator-min-microvolt = <810000>;
		regulator-max-microvolt = <1080000>;
		regulator-name = "vdd-gpu";
	};

In drivers/regulator/axp20x-regulator.c, axp806_regulators defines DCDCC via
AXP_DESC_RANGES(), which leaves desc.ramp_delay as 0 and uses
axp20x_ops_range without a set_voltage_time or set_voltage_time_sel callback.

When Panfrost devfreq scales up the GPU OPP on OrangePi One Plus or OrangePi
Lite2, the call chain:

	_set_opp()
	  -> _generic_set_opp_regulator()
	  -> regulator_set_voltage_Unlocked()
	  -> _regulator_do_set_voltage()
	  -> _regulator_set_voltage_time()

checks rdev->constraints->ramp_delay and rdev->desc->ramp_delay. Because both
are 0, _regulator_set_voltage_time() returns 0 and _set_opp() immediately
raises CLK_GPU via opp_table->config_clks() before the AXP805 DCDCC buck
regulator output has ramped up to the target voltage.

All other AXP805-based H6 board device trees that include
sun50i-h6-gpu-opp.dtsi (sun50i-h6-beelink-gs1.dts, sun50i-h6-orangepi-3.dts,
sun50i-h6-pine-h64.dts, and sun50i-h6-taiqicat-a01.dts) set
regulator-ramp-delay = <2500> on reg_dcdcc (added in commits 67533f873ad7,
ebae33c3f6ce, and fe79ea577be8).

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20261104184940.882833-1-jernej.skrabec@gmail.com?part=1