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Message-ID: <CAPDyKFqL9Xpau1BDnaa828s066zj=aVOAQOy1tCS=ztKN0ZsfA@mail.gmail.com>
Date: Tue, 3 Jun 2025 14:25:04 +0200
From: Ulf Hansson <ulf.hansson@...aro.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>,
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 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.
[...]
Kind regards
Uffe
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