Re: [PATCH 3/4] arm64: dts: rockchip: Add HDMI1 PHY PLL clock source to VOP2 on RK3588

[Sebastian Reichel]

Hi,

On Tue, Feb 18, 2025 at 08:17:46PM +0800, Jianfeng Liu wrote:
> On Tue, 18 Feb 2025 11:00:57 +0100, Heiko Stübnerwrote:
> >So I guess step1, check what error is actually returned.
> 
> I have checked that the return value is -517:
> 
> rockchip-drm display-subsystem: [drm] *ERROR* failed to get pll_hdmiphy1 with -517
> 
> >Step2 check if clk_get_optional need to be adapted or alternatively
> >catch the error in the vop2 and set the clock to NULL ourself in that case.
> 
> I tried the following patch to set the clock to NULL when clk_get_optional
> failed with value -517, and hdmi0 is working now. There are also some
> boards like rock 5 itx which only use hdmi1, I think we should also add
> this logic to vop2->pll_hdmiphy0.
> 
> @@ -3733,6 +3751,15 @@ static int vop2_bind(struct device *dev, struct device *master, void *data)
>  		return PTR_ERR(vop2->pll_hdmiphy0);
>  	}
>  
> +	vop2->pll_hdmiphy1 = devm_clk_get_optional(vop2->dev, "pll_hdmiphy1");
> +	if (IS_ERR(vop2->pll_hdmiphy1)) {
> +		drm_err(vop2->drm, "failed to get pll_hdmiphy1 with %d\n", vop2->pll_hdmiphy1);
> +		if (vop2->pll_hdmiphy1 == -EPROBE_DEFER)
> +			vop2->pll_hdmiphy1 = NULL;
> +		else
> +			return PTR_ERR(vop2->pll_hdmiphy1);
> +	}
> +

This first of all shows, that we should replace drm_err in this
place with dev_err_probe(), which hides -EPROBE_DEFER errors by
default and instead captures the reason for /sys/kernel/debug/devices_deferred.

Second what you are doing in the above suggestion will break kernel
configurations where VOP is built-in and the HDMI PHY is build as a
module.

But I also think it would be better to have the clocks defined in the
SoC level DT. I suppose that means vop2_bind would have to check if
the HDMI controller <ID> is enabled and only requests pll_hdmiphy<ID>
based on that. Considering there is the OF graph pointing from VOP
to the enabled HDMI controllers, it should be able to do that.

Greetings,

-- Sebastian

>  	vop2->irq = platform_get_irq(pdev, 0);
>  	if (vop2->irq < 0) {
>  		drm_err(vop2->drm, "cannot find irq for vop2\n");
> 
> Best regards,
> Jianfeng

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