Re: [PATCH 3/3] arm64: dts: rockchip: Add HDMI PHY PLL clock source to VOP2 on rk3576

From: Cristian Ciocaltea <cristian.ciocaltea@collabora.com>
To: "Detlev Casanova" <detlev.casanova@collabora.com>,
	"Sandy Huang" <hjc@rock-chips.com>,
	"Heiko Stübner" <heiko@sntech.de>,
	"Andy Yan" <andy.yan@rock-chips.com>,
	"Maarten Lankhorst" <maarten.lankhorst@linux.intel.com>,
	"Maxime Ripard" <mripard@kernel.org>,
	"Thomas Zimmermann" <tzimmermann@suse.de>,
	"David Airlie" <airlied@gmail.com>,
	"Simona Vetter" <simona@ffwll.ch>,
	"Rob Herring" <robh@kernel.org>,
	"Krzysztof Kozlowski" <krzk+dt@kernel.org>,
	"Conor Dooley" <conor+dt@kernel.org>
Cc: kernel@collabora.com, Andy Yan <andyshrk@163.com>,
	Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>,
	dri-devel@lists.freedesktop.org, devicetree@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	linux-rockchip@lists.infradead.org, linux-kernel@vger.kernel.org,
	stable@vger.kernel.org
Subject: Re: [PATCH 3/3] arm64: dts: rockchip: Add HDMI PHY PLL clock source to VOP2 on rk3576
Date: Thu, 12 Jun 2025 08:51:05 +0300	[thread overview]
Message-ID: <33376472-679b-406f-aadb-41dd540c47cf@collabora.com> (raw)
In-Reply-To: <6011857.DvuYhMxLoT@trenzalore>

Hi Detlev,

On 6/12/25 3:00 AM, Detlev Casanova wrote:
> Hi Cristian,
> 
> On Wednesday, 11 June 2025 17:47:49 EDT Cristian Ciocaltea wrote:
>> Since commit c871a311edf0 ("phy: rockchip: samsung-hdptx: Setup TMDS
>> char rate via phy_configure_opts_hdmi"), the workaround of passing the
>> rate from DW HDMI QP bridge driver via phy_set_bus_width() became
>> partially broken, as it cannot reliably handle mode switches anymore.
>>
>> Attempting to fix this up at PHY level would not only introduce
>> additional hacks, but it would also fail to adequately resolve the
>> display issues that are a consequence of the system CRU limitations.
>>
>> Instead, proceed with the solution already implemented for RK3588: make
>> use of the HDMI PHY PLL as a better suited DCLK source for VOP2. This
>> will not only address the aforementioned problem, but it should also
>> facilitate the proper operation of display modes up to 4K@60Hz.
>>
>> It's worth noting that anything above 4K@30Hz still requires high TMDS
>> clock ratio and scrambling support, which hasn't been mainlined yet.
>>
>> Fixes: d74b842cab08 ("arm64: dts: rockchip: Add vop for rk3576")
>> Cc: stable@vger.kernel.org
>> Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@collabora.com>
>> ---
>>  arch/arm64/boot/dts/rockchip/rk3576.dtsi | 6 ++++--
>>  1 file changed, 4 insertions(+), 2 deletions(-)
>>
>> diff --git a/arch/arm64/boot/dts/rockchip/rk3576.dtsi
>> b/arch/arm64/boot/dts/rockchip/rk3576.dtsi index
>> 6a13fe0c3513fb2ff7cd535aa70e3386c37696e4..b1ac23035dd789f0478bf10c78c74ef16
>> 7d94904 100644 --- a/arch/arm64/boot/dts/rockchip/rk3576.dtsi
>> +++ b/arch/arm64/boot/dts/rockchip/rk3576.dtsi
>> @@ -1155,12 +1155,14 @@ vop: vop@27d00000 {
>>  				 <&cru HCLK_VOP>,
>>  				 <&cru DCLK_VP0>,
>>  				 <&cru DCLK_VP1>,
>> -				 <&cru DCLK_VP2>;
>> +				 <&cru DCLK_VP2>,
>> +				 <&hdptxphy>;
>>  			clock-names = "aclk",
>>  				      "hclk",
>>  				      "dclk_vp0",
>>  				      "dclk_vp1",
>> -				      "dclk_vp2";
>> +				      "dclk_vp2",
>> +				      "pll_hdmiphy0";
>>  			iommus = <&vop_mmu>;
>>  			power-domains = <&power RK3576_PD_VOP>;
>>  			rockchip,grf = <&sys_grf>;
> 
> I tested this on the ROCK 4D and can confirm that:
>  - New modes like 2K are now working
>  - Mode changes is now correctly supported
> 
> So,
> Tested-By: Detlev Casanova <detlev.casanova@collabora.com>

Thanks for taking the time to perform all these tests!

Cristian