linux-kernel - Re: [PATCH v7 0/3] Add T-HEAD TH1520 VO clock support for LicheePi 4A GPU enablement

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Message-ID: <50da445f-d6f9-407d-b25d-5b9c7ccf867c@samsung.com>
Date: Tue, 22 Apr 2025 16:54:20 +0200
From: Michal Wilczynski <m.wilczynski@...sung.com>
To: sboyd@...nel.org, Drew Fustini <drew@...7.com>
Cc: linux-clk@...r.kernel.org, devicetree@...r.kernel.org,
	linux-kernel@...r.kernel.org, linux-riscv@...ts.infradead.org,
	"mturquette@...libre.com" <mturquette@...libre.com>, Rob Herring
	<robh@...nel.org>, "krzk+dt@...nel.org" <krzk+dt@...nel.org>,
	"conor+dt@...nel.org" <conor+dt@...nel.org>, Guo Ren <guoren@...nel.org>, Fu
	Wei <wefu@...hat.com>, "paul.walmsley@...ive.com"
	<paul.walmsley@...ive.com>, "palmer@...belt.com" <palmer@...belt.com>,
	"aou@...s.berkeley.edu" <aou@...s.berkeley.edu>, alex@...ti.fr,
	"jszhang@...nel.org" <jszhang@...nel.org>, Philipp Zabel
	<p.zabel@...gutronix.de>, Marek Szyprowski <m.szyprowski@...sung.com>
Subject: Re: [PATCH v7 0/3] Add T-HEAD TH1520 VO clock support for LicheePi
 4A GPU enablement



On 4/3/25 11:44, Michal Wilczynski wrote:
> This is a subset of a larger patch series enabling the Imagination BXM-4-64 GPU
> on the LicheePi 4A board, which is powered by the T-HEAD TH1520 SoC. While the
> full series includes power-domain, reset, and firmware changes, this part
> focuses solely on the clock subsystem needed for the GPU and other VO (video
> output) blocks. By merging these clock patches independently, we prepare the
> groundwork for future GPU integration via the `drm/imagination` driver.
> 
> The T-HEAD TH1520 SoC features multiple clock controllers. Initially, only the
> AP clock controller was supported upstream. The patches below add support for
> the VO (video output) clock controller, which manages GPU-related gates, HDMI,
> and other multimedia clocks.
> 
> Bigger series cover letter:
> https://lore.kernel.org/all/20250219140239.1378758-1-m.wilczynski@samsung.com/
> 
> v7:
> - remove commits 3,4 from the patch series, those would handle empty MEM clock
>   stub, and reset management. It's not necessary anymore, as this would be
>   implemented in power-domain driver
> - added the device tree patch at the end for the SoC maintainers to take after
>   the other patches get OK-ed
> - added Acked-by, from Connor for the dt-binding patch
> - re-added Reviewed-by from Krzysztof, as the dt-binding patch is the same as
>   for the v5
> 
> v6:
> - squashed the "dt-bindings: clock: thead: Add GPU clkgen reset property"
>   with the "dt-bindings: clock: thead: Add TH1520 VO clock controller". As
>   a result, also removed the Reviewed-by from Krzysztof, since the new
>   resets property has been introduced, which is mandatory in the VO
>   case
> 
> v5:
> - introduced a new macro CCU_GATE_CLK_OPS, which allows providing custom clk_ops.
>   In the case of the 'MEM' clock, it provides empty clk_nops. Later, this clock
>   is provided to the GPU node, thereby avoiding any ABI breakage
> - used the CCU_GATE_CLK_OPS macro to implement a workaround for de-asserting
>   the clkgen reset only after both core and sys clocks are enabled. This
>   sequence is required to properly initialize the GPU
> 
> v4:
>  - enhanced documentation for new Video Output (VO) clock inputs in device tree
>    bindings
> 
> v3:
>  - reworked driver to support multiple clock controllers through .compatible
>    and .data instead of using multiple address spaces in dt-binding. This change
>    allows to re-use the driver code for multiple clock controllers
> 
> v2:
>  - removed AP_SUBSYS clock refactoring commits (1-6):
>  - instead of refactoring, I opted to extend the current driver and its
>    associated device tree node to include support for a second address space.
>  - resolved all checkpatch issues using --strict, except for the call to
>    devm_clk_hw_register_gate_parent_data().  The current implementation remains
>    preferable in this context, and clang-format aligns with this choice
> 
> Michal Wilczynski (3):
>   dt-bindings: clock: thead: Add TH1520 VO clock controller
>   clk: thead: Add clock support for VO subsystem in T-HEAD TH1520 SoC
>   riscv: dts: thead: Add device tree VO clock controller
> 
>  .../bindings/clock/thead,th1520-clk-ap.yaml   |  17 +-
>  arch/riscv/boot/dts/thead/th1520.dtsi         |   7 +
>  drivers/clk/thead/clk-th1520-ap.c             | 196 +++++++++++++++---
>  .../dt-bindings/clock/thead,th1520-clk-ap.h   |  34 +++
>  4 files changed, 223 insertions(+), 31 deletions(-)
> 

Hi Stephen, I think Drew is already collecting DT commits for the next
merge window. Do you think the patches 1-2 will make it for the 6.16
release ?

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