arm64: dts: imx8mm-beacon: Enable PCIe

The baseboard supports a PCIe slot with a 100MHz reference clock,
but it's controlled by a different GPIO, so a gated clock is
required.
Signed-off-by: Adam Ford <aford173@gmail.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm64/boot/dts/freescale/imx8mm-beacon-baseboard.dtsi

@@ -3,6 +3,8 @@
  * Copyright 2020 Compass Electronics Group, LLC
  */
 
+#include <dt-bindings/phy/phy-imx8-pcie.h>
+
 / {
 	leds {
 		compatible = "gpio-leds";
@@ -34,6 +36,19 @@ led3 {
 		};
 	};
 
+	pcie0_refclk: pcie0-refclk {
+		compatible = "fixed-clock";
+		#clock-cells = <0>;
+		clock-frequency = <100000000>;
+	};
+
+	pcie0_refclk_gated:  pcie0-refclk-gated {
+		compatible = "gpio-gate-clock";
+		clocks = <&pcie0_refclk>;
+		#clock-cells = <0>;
+		enable-gpios = <&pca6416_1 2 GPIO_ACTIVE_LOW>;
+	};
+
 	reg_audio: regulator-audio {
 		compatible = "regulator-fixed";
 		regulator-name = "3v3_aud";
@@ -64,6 +79,16 @@ reg_camera: regulator-camera {
 		startup-delay-us = <100000>;
 	};
 
+	reg_pcie0: regulator-pcie {
+		compatible = "regulator-fixed";
+		regulator-name = "pci_pwr_en";
+		regulator-min-microvolt = <3300000>;
+		regulator-max-microvolt = <3300000>;
+		enable-active-high;
+		gpio = <&pca6416_1 1 GPIO_ACTIVE_HIGH>;
+		startup-delay-us = <100000>;
+	};
+
 	reg_usdhc2_vmmc: regulator-usdhc2 {
 		compatible = "regulator-fixed";
 		regulator-name = "VSD_3V3";
@@ -202,6 +227,32 @@ imx8mm_mipi_csi_in: endpoint {
 	};
 };
 
+&pcie_phy {
+	fsl,refclk-pad-mode = <IMX8_PCIE_REFCLK_PAD_INPUT>;
+	fsl,tx-deemph-gen1 = <0x2d>;
+	fsl,tx-deemph-gen2 = <0xf>;
+	fsl,clkreq-unsupported;
+	clocks = <&pcie0_refclk_gated>;
+	clock-names = "ref";
+	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_gated>;
+	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>;
@@ -308,6 +359,12 @@ MX8MM_IOMUXC_SAI3_RXC_GPIO4_IO29     0x19
 		>;
 	};
 
+	pinctrl_pcie0: pcie0grp {
+		fsl,pins = <
+			MX8MM_IOMUXC_SAI2_RXFS_GPIO4_IO21       0x41
+		>;
+	};
+
 	pinctrl_sai3: sai3grp {
 		fsl,pins = <
 			MX8MM_IOMUXC_SAI3_TXFS_SAI3_TX_SYNC     0xd6