arm64: dts: imx8mm-evk: Add the pcie support on imx8mm evk board

Add the PCIe support on iMX8MM EVK boards.
And set the default reference clock mode.
Signed-off-by: Richard Zhu <hongxing.zhu@nxp.com>
Tested-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>
Reviewed-by: Tim Harvey <tharvey@gateworks.com>
Tested-by: Tim Harvey <tharvey@gateworks.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm64/boot/dts/freescale/imx8mm-evk.dtsi

@@ -5,6 +5,7 @@
 
 /dts-v1/;
 
+#include <dt-bindings/phy/phy-imx8-pcie.h>
 #include <dt-bindings/usb/pd.h>
 #include "imx8mm.dtsi"
 
@@ -30,6 +31,23 @@ status {
 		};
 	};
 
+	pcie0_refclk: pcie0-refclk {
+		compatible = "fixed-clock";
+		#clock-cells = <0>;
+		clock-frequency = <100000000>;
+	};
+
+	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 = <&gpio1 5 GPIO_ACTIVE_HIGH>;
+		enable-active-high;
+	};
+
 	reg_usdhc2_vmmc: regulator-usdhc2 {
 		compatible = "regulator-fixed";
 		pinctrl-names = "default";
@@ -296,6 +314,30 @@ pca6416: gpio@20 {
 	};
 };
 
+&pcie_phy {
+	fsl,refclk-pad-mode = <IMX8_PCIE_REFCLK_PAD_INPUT>;
+	fsl,tx-deemph-gen1 = <0x2d>;
+	fsl,tx-deemph-gen2 = <0xf>;
+	clocks = <&pcie0_refclk>;
+	status = "okay";
+};
+
+&pcie0 {
+	pinctrl-names = "default";
+	pinctrl-0 = <&pinctrl_pcie0>;
+	reset-gpio = <&gpio4 21 GPIO_ACTIVE_LOW>;
+	clocks = <&clk IMX8MM_CLK_PCIE1_ROOT>, <&clk IMX8MM_CLK_PCIE1_AUX>,
+		 <&pcie0_refclk>;
+	clock-names = "pcie", "pcie_aux", "pcie_bus";
+	assigned-clocks = <&clk IMX8MM_CLK_PCIE1_AUX>,
+			  <&clk IMX8MM_CLK_PCIE1_CTRL>;
+	assigned-clock-rates = <10000000>, <250000000>;
+	assigned-clock-parents = <&clk IMX8MM_SYS_PLL2_50M>,
+				 <&clk IMX8MM_SYS_PLL2_250M>;
+	vpcie-supply = <&reg_pcie0>;
+	status = "okay";
+};
+
 &sai3 {
 	pinctrl-names = "default";
 	pinctrl-0 = <&pinctrl_sai3>;
@@ -413,6 +455,19 @@ MX8MM_IOMUXC_I2C3_SDA_I2C3_SDA			0x400001c3
 		>;
 	};
 
+	pinctrl_pcie0: pcie0grp {
+		fsl,pins = <
+			MX8MM_IOMUXC_I2C4_SCL_PCIE1_CLKREQ_B    0x61
+			MX8MM_IOMUXC_SAI2_RXFS_GPIO4_IO21       0x41
+		>;
+	};
+
+	pinctrl_pcie0_reg: pcie0reggrp {
+		fsl,pins = <
+			MX8MM_IOMUXC_GPIO1_IO05_GPIO1_IO5       0x41
+		>;
+	};
+
 	pinctrl_pmic: pmicirqgrp {
 		fsl,pins = <
 			MX8MM_IOMUXC_GPIO1_IO03_GPIO1_IO3		0x141