Message-ID: <a1d2fc77-ac57-49d4-a13e-cc391e6e2b92@samsung.com>
Date: Mon, 29 Dec 2025 17:32:03 +0100
From: Michal Wilczynski <m.wilczynski@...sung.com>
To: Icenowy Zheng <zhengxingda@...as.ac.cn>, 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>, Rob Herring <robh@...nel.org>, Krzysztof
	Kozlowski <krzk+dt@...nel.org>, Conor Dooley <conor+dt@...nel.org>, Drew
	Fustini <fustini@...nel.org>, Guo Ren <guoren@...nel.org>, Fu Wei
	<wefu@...hat.com>, Philipp Zabel <p.zabel@...gutronix.de>, Heiko Stuebner
	<heiko@...ech.de>, Andrzej Hajda <andrzej.hajda@...el.com>, Neil Armstrong
	<neil.armstrong@...aro.org>, Robert Foss <rfoss@...nel.org>, Laurent
	Pinchart <Laurent.pinchart@...asonboard.com>, Jonas Karlman
	<jonas@...boo.se>, Jernej Skrabec <jernej.skrabec@...il.com>
Cc: Han Gao <rabenda.cn@...il.com>, Yao Zi <ziyao@...root.org>,
	dri-devel@...ts.freedesktop.org, devicetree@...r.kernel.org,
	linux-kernel@...r.kernel.org, linux-riscv@...ts.infradead.org
Subject: Re: [PATCH v4 0/9] Verisilicon DC8200 driver (and adaption to
 TH1520)



On 12/24/25 17:11, Icenowy Zheng wrote:
> This patchset tries to add a driver for Verisilicon DC8200 driver, and
> demonstrates the driver on T-Head TH1520 with its HDMI output.
> 
> This display controller IP is used on StarFive JH7110 too, but as the
> HDMI controller used there isn't as common as the DesignWare one, I
> choose to use TH1520 in this patchset.
> 
> The DC driver is written with other DC-series (mainly DC8000, which is
> known to be used on Eswin EIC7700 SoC) display controllers in mind, and
> uses the identification registers available on all Vivante branded IPs.
> A known exception is DCNano display controller, which is unlikely to be
> supported by this driver because of totally different register map and
> no known identification registers. (P.S. the in-tree loongson DRM driver
> seems to be for some DCNano instances based on the register map.)
> 
> The HDMI controller seems to come with some common PHY by Synopsys, the
> DesignWare HDMI TX 2.0 PHY. By searching a few register names from the
> BSP driver of that PHY, that PHY seems to be used by a in-tree dw-hdmi
> glue, rcar_dw_hdmi -- an updated downstream version of rcar_dw_hdmi
> contains all 6 registers set here in the th1520-dw-hdmi driver. Some
> more suprising thing is that RK3288 uses the same PHY too, but the
> in-tree dw_hdmi-rockchip driver writes the configuration data array in a
> weird way to reuse the HDMI 3D TX PHY configuring function. It might be
> valuable to add common configuring function and configuration data
> definition for this HDMI 2.0 PHY too, but the current driver in this
> patchset simply duplicated most configuration logic from rcar_dw_hdmi
> driver (but with 3 extra configuration registers configured).
> 
> Icenowy Zheng (9):
>   dt-bindings: vendor-prefixes: add verisilicon
>   dt-bindings: display: add verisilicon,dc
>   drm: verisilicon: add a driver for Verisilicon display controllers
>   dt-bindings: display/bridge: add binding for TH1520 HDMI controller
>   drm/bridge: add a driver for T-Head TH1520 HDMI controller
>   riscv: dts: thead: add DPU and HDMI device tree nodes
>   riscv: dts: thead: lichee-pi-4a: enable HDMI
>   MAINTAINERS: assign myself as maintainer for verisilicon DC driver
>   mailmap: map all Icenowy Zheng's mail addresses
> 

I tested this patchset on the Lichee Pi 4A (TH1520). I successfully ran a 
fully hardware accelerated graphics stack using Weston and Zink over the 
HDMI output.

I have documented the reproduction steps and test results here:
[1] https://mwilczynski.dev/posts/riscv-gpu-zink/#building-the-stack-reproduction-guide

Great work, thank you!

Feel free to add to driver and DTS patches (3,5,6,7).
Tested-by: Michal Wilczynski <m.wilczynski@...sung.com>

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

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