linux-kernel - Re: [PATCH v3 6/8] riscv: dts: thead: Add GPU power sequencer node

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Message-ID: <20250603-gleaming-mammoth-of-kindness-538add@kuoka>
Date: Tue, 3 Jun 2025 15:22:05 +0200
From: Krzysztof Kozlowski <krzk@...nel.org>
To: Michal Wilczynski <m.wilczynski@...sung.com>
Cc: Drew Fustini <drew@...7.com>, Guo Ren <guoren@...nel.org>, 
	Fu Wei <wefu@...hat.com>, Rob Herring <robh@...nel.org>, 
	Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor Dooley <conor+dt@...nel.org>, 
	Bartosz Golaszewski <brgl@...ev.pl>, Philipp Zabel <p.zabel@...gutronix.de>, 
	Frank Binns <frank.binns@...tec.com>, Matt Coster <matt.coster@...tec.com>, 
	Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>, Maxime Ripard <mripard@...nel.org>, 
	Thomas Zimmermann <tzimmermann@...e.de>, David Airlie <airlied@...il.com>, 
	Simona Vetter <simona@...ll.ch>, Paul Walmsley <paul.walmsley@...ive.com>, 
	Palmer Dabbelt <palmer@...belt.com>, Albert Ou <aou@...s.berkeley.edu>, 
	Alexandre Ghiti <alex@...ti.fr>, Ulf Hansson <ulf.hansson@...aro.org>, 
	Marek Szyprowski <m.szyprowski@...sung.com>, linux-riscv@...ts.infradead.org, devicetree@...r.kernel.org, 
	linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org, dri-devel@...ts.freedesktop.org
Subject: Re: [PATCH v3 6/8] riscv: dts: thead: Add GPU power sequencer node

On Fri, May 30, 2025 at 12:23:53AM GMT, Michal Wilczynski wrote:
> Add the device tree node for the T-HEAD TH1520 GPU power sequencer
> (gpu_pwrseq) to the th1520.dtsi file.
> 
> This node instantiates the thead,th1520-gpu-pwrseq driver, which

Explain the hardware, not what drivers do.

> is responsible for managing the GPU's power-on/off sequence. The node
> specifies the gpu-clkgen reset, which is one of the resources
> controlled by this sequencer.
> 
> Signed-off-by: Michal Wilczynski <m.wilczynski@...sung.com>
> ---
>  arch/riscv/boot/dts/thead/th1520.dtsi | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/arch/riscv/boot/dts/thead/th1520.dtsi b/arch/riscv/boot/dts/thead/th1520.dtsi
> index bdbb1b985b0b76cf669a9bf40c6ec37258329056..6170eec79e919b606a2046ac8f52db07e47ef441 100644
> --- a/arch/riscv/boot/dts/thead/th1520.dtsi
> +++ b/arch/riscv/boot/dts/thead/th1520.dtsi
> @@ -238,6 +238,12 @@ aon: aon {
>  		#power-domain-cells = <1>;
>  	};
>  
> +	gpu_pwrseq: pwrseq {

Node names should be generic. See also an explanation and list of
examples (not exhaustive) in DT specification:
https://devicetree-specification.readthedocs.io/en/latest/chapter2-devicetree-basics.html#generic-names-recommendation

> +		compatible = "thead,th1520-gpu-pwrseq";
> +		resets = <&rst TH1520_RESET_ID_GPU_CLKGEN>;
> +		reset-names = "gpu-clkgen";

What is the point of pwrseq if there is no consumer/user of it? Looks
like simple placeholder and anyway maybe the future consumer should just
use reset directly.

Best regards,
Krzysztof