Subject: Re: [PATCH] arm64: dts: rockchip: align bindings to PCIe spec

From: Geraldo Nascimento <[email-masked]>
Date: Wed, 5 Nov 2025 17:02:21 -0300

On Wed, Nov 05, 2025 at 04:56:36PM +0800, Shawn Lin wrote:
> 在 2025/11/05 星期三 16:18, Geraldo Nascimento 写道:
> > 
> > Hi Shawn, glad to hear from you.
> > 
> > Perhaps the following change is better? It resolves the issue
> > without the added complication of open drain. After you questioned
> > if open drain is actually part of the spec, I remembered that
> > GPIO_OPEN_DRAIN is actually (GPIO_SINGLE_ENDED | GPIO_LINE_OPEN_DRAIN)
> > so I decided to test with just GPIO_SINGLE_ENDED and it works.
> 
> 
> Does that work for you too?
> 
> &pcie0 {
> 	ep-gpios = <&gpio0 RK_PB4 GPIO_ACTIVE_HIGH>;
>   	num-lanes = <4>;
> -	pinctrl-0 = <&pcie_clkreqnb_cpm>;
> +	pinctrl-0 = <&pcie_clkreqnb_cpm>, <&pcie_perst>;
>   	pinctrl-names = "default";
>   	vpcie0v9-supply = <&vcca_0v9>;	/* VCC_0V9_S0 */
>   	vpcie1v8-supply = <&vcca_1v8>;	/* VCC_1V8_S0 */
> @@ -408,6 +408,10 @@ pcie {
>   		pcie_pwr: pcie-pwr {
>   			rockchip,pins = <4 RK_PD4 RK_FUNC_GPIO &pcfg_pull_up>;
>   		};
> +		pcie_perst: pcie-perst {
> +			rockchip,pins = <0 RK_PB4 RK_FUNC_GPIO &pcfg_pull_up>;
> +		};
> +
>   	};

Hi Shawn,

No, that does not work.

I believe the pull-up mux became needed because I was forcing open drain
on PERST#.

Thanks,
Geraldo Nascimento