Re: (EXT) [PATCH v2 6/7] arm64: dts: imx8mp-evk: Add PCIe support

[Alexander Stein <alexander.stein@xxxxxxxxxxxxxxx>]

Hello Richard,

thanks for providing PCIe support for iMX8MP.

Am Montag, 7. März 2022, 10:07:33 CET schrieb Richard Zhu:
> Add PCIe support on i.MX8MP EVK board.
> 
> Signed-off-by: Richard Zhu <hongxing.zhu@xxxxxxx>
> ---
>  arch/arm64/boot/dts/freescale/imx8mp-evk.dts | 55 ++++++++++++++++++++
>  1 file changed, 55 insertions(+)
> 
> diff --git a/arch/arm64/boot/dts/freescale/imx8mp-evk.dts
> b/arch/arm64/boot/dts/freescale/imx8mp-evk.dts index
> 2eb943210678..ed77455a3f73 100644
> --- a/arch/arm64/boot/dts/freescale/imx8mp-evk.dts
> +++ b/arch/arm64/boot/dts/freescale/imx8mp-evk.dts
> @@ -5,6 +5,7 @@
> 
>  /dts-v1/;
> 
> +#include <dt-bindings/phy/phy-imx8-pcie.h>
>  #include "imx8mp.dtsi"
> 
>  / {
> @@ -33,6 +34,12 @@ memory@40000000 {
>  		      <0x1 0x00000000 0 0xc0000000>;
>  	};
> 
> +	pcie0_refclk: pcie0-refclk {
> +		compatible = "fixed-clock";
> +			#clock-cells = <0>;
> +			clock-frequency = <100000000>;
> +	};
> +
>  	reg_can1_stby: regulator-can1-stby {
>  		compatible = "regulator-fixed";
>  		regulator-name = "can1-stby";
> @@ -55,6 +62,17 @@ reg_can2_stby: regulator-can2-stby {
>  		enable-active-high;
>  	};
> 
> +	reg_pcie0: regulator-pcie {
> +		compatible = "regulator-fixed";
> +		pinctrl-names = "default";
> +		pinctrl-0 = <&pinctrl_pcie0_reg>;
> +		regulator-name = "MPCIE_3V3";
> +		regulator-min-microvolt = <3300000>;
> +		regulator-max-microvolt = <3300000>;
> +		gpio = <&gpio2 6 GPIO_ACTIVE_HIGH>;
> +		enable-active-high;
> +	};
> +
>  	reg_usdhc2_vmmc: regulator-usdhc2 {
>  		compatible = "regulator-fixed";
>  		pinctrl-names = "default";
> @@ -297,6 +315,30 @@ pca6416: gpio@20 {
>  	};
>  };
> 
> +&pcie_phy {
> +	fsl,refclk-pad-mode = <IMX8_PCIE_REFCLK_PAD_INPUT>;
> +	clocks = <&pcie0_refclk>;
> +	clock-names = "ref";
> +	status = "okay";
> +};
> +
> +&pcie{
> +	pinctrl-names = "default";
> +	pinctrl-0 = <&pinctrl_pcie0>;
> +	reset-gpio = <&gpio2 7 GPIO_ACTIVE_LOW>;
> +	clocks = <&clk IMX8MP_CLK_HSIO_ROOT>,
> +		 <&clk IMX8MP_CLK_PCIE_ROOT>,
> +		 <&clk IMX8MP_CLK_HSIO_AXI>;
> +	clock-names = "pcie", "pcie_aux", "pcie_bus";

This causes the following warnings in dtbs_check (paths stripped):
imx8mp-evk.dtb: pcie@33800000: clock-names:1: 'pcie_bus' was expected
        From schema: Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.yaml
imx8mp-evk.dtb: pcie@33800000: clock-names:2: 'pcie_phy' was expected
        From schema: Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.yaml

The bindings want 4 clocks for imx8mq (and imx8mp which seems similar):
* pcie
* pcie_bus
* pcie_phy
* pcie_aux

Ignoring the order there is no pcie_phy clock anymore, it was removed in 
commit 1840518ae7de ("clk: imx8mp: Remove the none exist pcie clocks"). I was 
wondering why, because the PCIE_PHY_CLK_ROOT at register 0xa380 inside CCM is 
listed in RM.
So there is a clock missing for 'pcie_phy' or the binding needs some update 
for imx8mp, no?

Regards,
Alexander

> +	assigned-clocks = <&clk IMX8MP_CLK_HSIO_AXI>,
> +			  <&clk IMX8MP_CLK_PCIE_AUX>;
> +	assigned-clock-rates = <500000000>, <10000000>;
> +	assigned-clock-parents = <&clk IMX8MP_SYS_PLL2_500M>,
> +				 <&clk IMX8MP_SYS_PLL2_50M>;
> +	vpcie-supply = <&reg_pcie0>;
> +	status = "okay";
> +};
> +
>  &snvs_pwrkey {
>  	status = "okay";
>  };
> @@ -442,6 +484,19 @@ MX8MP_IOMUXC_I2C3_SDA__I2C3_SDA		0x400001c3
> 
>  		>;
> 
>  	};
> 
> +	pinctrl_pcie0: pcie0grp {
> +		fsl,pins = <
> +			MX8MP_IOMUXC_I2C4_SCL__PCIE_CLKREQ_B	
0x61 /* open drain, pull up */
> +			MX8MP_IOMUXC_SD1_DATA5__GPIO2_IO07	
0x41
> +		>;
> +	};
> +
> +	pinctrl_pcie0_reg: pcie0reggrp {
> +		fsl,pins = <
> +			MX8MP_IOMUXC_SD1_DATA4__GPIO2_IO06	
0x41
> +		>;
> +	};
> +
>  	pinctrl_pmic: pmicgrp {
>  		fsl,pins = <
>  			MX8MP_IOMUXC_GPIO1_IO03__GPIO1_IO03	
0x000001c0