arm64: dts: ti: iot2050: Add support for M.2 variant

The M.2 variant comes with 2 slots, one B-keyed and another one E-keyed.
They are configured by the firmware during startup. Also the device tree
will be adjusted according to the detect or manually configured
interface mode by the firmware. The kernel only carries a single
configuration as base device tree. It has to be built with a symbols
node so that the firmware can apply overlays for the connector modes.
Signed-off-by: chao zeng <chao.zeng@siemens.com>
[Jan: refactored to a single DT]
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Reviewed-by: Siddharth Vadapalli <s-vadapalli@ti.com>
Link: https://lore.kernel.org/r/878e3a023767b5a6d9d2cff09015678aaba13fce.1674110442.git.jan.kiszka@siemens.comSigned-off-by: Vignesh Raghavendra <vigneshr@ti.com>

arch/arm64/boot/dts/ti/Makefile

@@ -10,8 +10,11 @@ dtb-$(CONFIG_ARCH_K3) += k3-am654-base-board.dtb
 dtb-$(CONFIG_ARCH_K3) += k3-am6528-iot2050-basic.dtb
 dtb-$(CONFIG_ARCH_K3) += k3-am6528-iot2050-basic-pg2.dtb
 dtb-$(CONFIG_ARCH_K3) += k3-am6548-iot2050-advanced.dtb
+dtb-$(CONFIG_ARCH_K3) += k3-am6548-iot2050-advanced-m2.dtb
 dtb-$(CONFIG_ARCH_K3) += k3-am6548-iot2050-advanced-pg2.dtb
 
+DTC_FLAGS_k3-am6548-iot2050-advanced-m2 += -@
+
 dtb-$(CONFIG_ARCH_K3) += k3-am68-sk-base-board.dtb
 
 dtb-$(CONFIG_ARCH_K3) += k3-j721e-beagleboneai64.dtb

arch/arm64/boot/dts/ti/k3-am6548-iot2050-advanced-m2.dts

+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) Siemens AG, 2018-2023
+ *
+ * Authors:
+ *   Chao Zeng <chao.zeng@siemens.com>
+ *   Jan Kiszka <jan.kiszka@siemens.com>
+ *
+ * AM6548-based (quad-core) IOT2050 M.2 variant (based on Advanced Product
+ * Generation 2), 2 GB RAM, 16 GB eMMC, USB-serial converter on connector X30
+ *
+ * Product homepage:
+ * https://new.siemens.com/global/en/products/automation/pc-based/iot-gateways/simatic-iot2050.html
+ */
+
+#include "k3-am6548-iot2050-advanced-common.dtsi"
+#include "k3-am65-iot2050-common-pg2.dtsi"
+
+/ {
+	compatible = "siemens,iot2050-advanced-m2", "ti,am654";
+	model = "SIMATIC IOT2050 Advanced M2";
+};
+
+&mcu_r5fss0 {
+	/* lock-step mode not supported on this board */
+	ti,cluster-mode = <0>;
+};
+
+&main_pmx0 {
+	main_m2_enable_pins_default: main-m2-enable-pins-default {
+		pinctrl-single,pins = <
+			AM65X_IOPAD(0x01c4, PIN_INPUT_PULLUP, 7)  /* (AH13) GPIO1_17 */
+		>;
+	};
+
+	main_bkey_pcie_reset: main-bkey-pcie-reset {
+		pinctrl-single,pins = <
+			AM65X_IOPAD(0x01bc, PIN_OUTPUT_PULLUP, 7)  /* (AG13) GPIO1_15 */
+		>;
+	};
+
+	main_pmx0_m2_config_pins_default: main-pmx0-m2-config-pins-default {
+		pinctrl-single,pins = <
+			AM65X_IOPAD(0x01c8, PIN_INPUT_PULLUP, 7)  /* (AE13) GPIO1_18 */
+			AM65X_IOPAD(0x01cc, PIN_INPUT_PULLUP, 7)  /* (AD13) GPIO1_19 */
+		>;
+	};
+
+	main_m2_pcie_mux_control: main-m2-pcie-mux-control {
+		pinctrl-single,pins = <
+			AM65X_IOPAD(0x0148, PIN_INPUT_PULLUP, 7)  /* (AG22) GPIO0_82 */
+			AM65X_IOPAD(0x0160, PIN_INPUT_PULLUP, 7)  /* (AE20) GPIO0_88 */
+			AM65X_IOPAD(0x0164, PIN_INPUT_PULLUP, 7)  /* (AF19) GPIO0_89 */
+		>;
+	};
+};
+
+&main_pmx1 {
+	main_pmx1_m2_config_pins_default: main-pmx1-m2-config-pins-default {
+		pinctrl-single,pins = <
+			AM65X_IOPAD(0x0018, PIN_INPUT_PULLUP, 7)  /* (B22) GPIO1_88 */
+			AM65X_IOPAD(0x001c, PIN_INPUT_PULLUP, 7)  /* (C23) GPIO1_89 */
+		>;
+	};
+};
+
+&main_gpio0 {
+	pinctrl-names = "default";
+	pinctrl-0 = <
+		&main_m2_pcie_mux_control
+		&arduino_io_d4_to_d9_pins_default
+	>;
+};
+
+&main_gpio1 {
+	pinctrl-names = "default";
+	pinctrl-0 = <
+		&main_m2_enable_pins_default
+		&main_pmx0_m2_config_pins_default
+		&main_pmx1_m2_config_pins_default
+		&cp2102n_reset_pin_default
+	>;
+};
+
+/*
+ * Base configuration for B-key slot with PCIe x2, E-key with USB 2.0 only.
+ * Firmware switches to other modes via device tree overlays.
+ */
+
+&serdes0 {
+	assigned-clocks = <&k3_clks 153 4>, <&serdes0 AM654_SERDES_CMU_REFCLK>;
+	assigned-clock-parents = <&k3_clks 153 8>, <&k3_clks 153 4>;
+};
+
+&pcie0_rc {
+	pinctrl-names = "default";
+	pinctrl-0 = <&main_bkey_pcie_reset>;
+
+	num-lanes = <2>;
+	phys = <&serdes0 PHY_TYPE_PCIE 1>, <&serdes1 PHY_TYPE_PCIE 1>;
+	phy-names = "pcie-phy0","pcie-phy1";
+	reset-gpios = <&main_gpio1 15 GPIO_ACTIVE_HIGH>;
+	status = "okay";
+};
+
+&pcie1_rc {
+	status = "disabled";
+};
+
+&dwc3_0 {
+	assigned-clock-parents = <&k3_clks 151 4>,  /* set REF_CLK to 20MHz i.e. PER0_PLL/48 */
+				 <&k3_clks 151 9>;  /* set PIPE3_TXB_CLK to CLK_12M_RC/256 (for HS only) */
+	/delete-property/ phys;
+	/delete-property/ phy-names;
+};
+
+&usb0 {
+	maximum-speed = "high-speed";
+	/delete-property/ snps,dis-u1-entry-quirk;
+	/delete-property/ snps,dis-u2-entry-quirk;
+};