linux-kernel - Re: [PATCH v3 0/8] Add TH1520 GPU support with power sequencing

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Message-ID: <00abf302-cc8c-47c7-8444-ea3791f70436@samsung.com>
Date: Tue, 3 Jun 2025 20:29:56 +0200
From: Michal Wilczynski <m.wilczynski@...sung.com>
To: Ulf Hansson <ulf.hansson@...aro.org>
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>, 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 0/8] Add TH1520 GPU support with power sequencing



On 6/3/25 14:25, Ulf Hansson wrote:
> On Fri, 30 May 2025 at 00:24, Michal Wilczynski
> <m.wilczynski@...sung.com> wrote:
>>
>> This patch series introduces support for the Imagination IMG BXM-4-64
>> GPU found on the T-HEAD TH1520 SoC. A key aspect of this support is
>> managing the GPU's complex power-up and power-down sequence, which
>> involves multiple clocks and resets.
>>
>> The TH1520 GPU requires a specific sequence to be followed for its
>> clocks and resets to ensure correct operation. Initial discussions and
>> an earlier version of this series explored managing this via the generic
>> power domain (genpd) framework. However, following further discussions
>> with kernel maintainers [1], the approach has been reworked to utilize
>> the dedicated power sequencing (pwrseq) framework.
>>
>> This revised series now employs a new pwrseq provider driver
>> (pwrseq-thead-gpu.c) specifically for the TH1520 GPU. This driver
>> encapsulates the SoC specific power sequence details. The Imagination
>> GPU driver (pvr_device.c) is updated to act as a consumer of this power
>> sequencer, requesting the "gpu-power" target. The sequencer driver,
>> during its match phase with the GPU device, acquires the necessary clock
>> and reset handles from the GPU device node to perform the full sequence.
>>
>> This approach aligns with the goal of abstracting SoC specific power
>> management details away from generic device drivers and leverages the
>> pwrseq framework as recommended.
> 
> Just wanted to share my view. I have looked through the series and to
> me this seems like the correct approach, nice work!
> 
> Feel free to add my Reviewed-by tag for the series, even if I think
> there may be some comments to address from Bartosz etc.

Thanks for providing the direction and reviewing the code, the pwrseq
API seems to be perfect to achieve the goals of this series. Appreciate
your help !

> 
> [...]
> 
> Kind regards
> Uffe
> 

Best regards,
-- 
Michal Wilczynski <m.wilczynski@...sung.com>