Re: [PATCH] arm64: dts: rockchip: Fix vdd_gpu voltage constraints on PinePhone Pro

[Adam Pigg <adam@piggz.co.uk>]

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On Sunday 10 November 2024 18:44:31 Greenwich Mean Time Dragan Simic wrote:
> The regulator-{min,max}-microvolt values for the vdd_gpu regulator in the
> PinePhone Pro device dts file are too restrictive, which prevents the
> highest GPU OPP from being used, slowing the GPU down unnecessarily.  Let's
> fix that by making the regulator-{min,max}-microvolt values less strict,
> using the voltage range that the Silergy SYR838 chip used for the vdd_gpu
> regulator is actually capable of producing. [1][2]
> 
> This also eliminates the following error messages from the kernel log:
> 
>   core: _opp_supported_by_regulators: OPP minuV: 1100000 maxuV: 1150000, not
> supported by regulator panfrost ff9a0000.gpu: _opp_add: OPP not supported
> by regulators (800000000)
> 
> These changes to the regulator-{min,max}-microvolt values make the PinePhone
> Pro device dts consistent with the dts files for other Rockchip
> RK3399-based boards and devices.  It's possible to be more strict here, by
> specifying the regulator-{min,max}-microvolt values that don't go outside
> of what the GPU actually may use, as the consumer of the vdd_gpu regulator,
> but those changes are left for a later directory-wide regulator cleanup.
> 
Ive tested this on my PPP and can provide the following outputs.

On a device without the patch:
# cat /sys/class/devfreq/ff9a0000.gpu/trans_stat
From  :   To
: 200000000 297000000 400000000 500000000 600000000   time(ms)
200000000:         0         0         0         0     12203   5387782
297000000:      8208         0         0         0      2973   2337382
400000000:       784      6283         0         0       439   1859857
500000000:        67       287      1093         0       284    389599
600000000:      3145      4611      6413      1730         0   1748889
Total transition : 48520

And with the patch:
[root@PinePhonePro defaultuser]# cat /sys/class/devfreq/ff9a0000.gpu/trans_stat 
     From  :   To
           : 200000000 297000000 400000000 500000000 600000000 800000000   
time(ms)
  200000000:         0         0         0         0         0       364    
188911
  297000000:       120         0         0         0         0       234     
31652
  400000000:        77       182         0         0         0        82     
32287
  500000000:        10        57        56         0         0        57     
13376
  600000000:        21        14        35        31         0        22      
9463
  800000000:       137       101       250       148       123         0     
97310
Total transition : 2121
[root@PinePhonePro defaultuser]# uptime
 11:56:24 up  3:34,  1 users,  load average: 2.77, 2.24, 1.70

I havnt noticed any issues, though I havnt done anything more in-depth than 
run the compositor and play a youtube video in the browser

> [1]
> https://files.pine64.org/doc/PinePhonePro/PinephonePro-Schematic-V1.0-20211
> 127.pdf [2]
> https://www.t-firefly.com/download/Firefly-RK3399/docs/Chip%20Specification
> s/DC-DC_SYR837_838.pdf
> 
> Fixes: 78a21c7d5952 ("arm64: dts: rockchip: Add initial support for Pine64
> PinePhone Pro") Cc: stable@vger.kernel.org
> Signed-off-by: Dragan Simic <dsimic@manjaro.org>
Tested-By: Adam Pigg <adam@piggz.co.uk>
> ---
>  arch/arm64/boot/dts/rockchip/rk3399-pinephone-pro.dts | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/arm64/boot/dts/rockchip/rk3399-pinephone-pro.dts
> b/arch/arm64/boot/dts/rockchip/rk3399-pinephone-pro.dts index
> 1a44582a49fb..956d64f5b271 100644
> --- a/arch/arm64/boot/dts/rockchip/rk3399-pinephone-pro.dts
> +++ b/arch/arm64/boot/dts/rockchip/rk3399-pinephone-pro.dts
> @@ -410,8 +410,8 @@ vdd_gpu: regulator@41 {
>  		pinctrl-names = "default";
>  		pinctrl-0 = <&vsel2_pin>;
>  		regulator-name = "vdd_gpu";
> -		regulator-min-microvolt = <875000>;
> -		regulator-max-microvolt = <975000>;
> +		regulator-min-microvolt = <712500>;
> +		regulator-max-microvolt = <1500000>;
>  		regulator-ramp-delay = <1000>;
>  		regulator-always-on;
>  		regulator-boot-on;
> 
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