Add a device tree overlay for SPI1 , UART3 and GPIO1 on
X27 connector.

By default, not all interfaces on the X27 connector are accessible
due to being disabled or set to alternative pin mux configurations.
This overlay activates and configures these interfaces to support
connections with external devices.

Signed-off-by: Wadim Egorov <w.egorov@phytec.de>
Signed-off-by: Daniel Schultz <d.schultz@phytec.de>
---
Changes in v2:
  Removed the spidev from main_spi1.

 arch/arm64/boot/dts/ti/Makefile               |  3 +
 ...phyboard-electra-x27-gpio1-spi1-uart3.dtso | 63 +++++++++++++++++++
 2 files changed, 66 insertions(+)
 create mode 100644 arch/arm64/boot/dts/ti/k3-am642-phyboard-electra-x27-gpio1-spi1-uart3.dtso

diff --git a/arch/arm64/boot/dts/ti/Makefile b/arch/arm64/boot/dts/ti/Makefile
index 8a4bdf87e2d4..03d4cecfc001 100644
--- a/arch/arm64/boot/dts/ti/Makefile
+++ b/arch/arm64/boot/dts/ti/Makefile
@@ -54,6 +54,7 @@ dtb-$(CONFIG_ARCH_K3) += k3-am642-evm-nand.dtb
 dtb-$(CONFIG_ARCH_K3) += k3-am642-phyboard-electra-rdk.dtb
 dtb-$(CONFIG_ARCH_K3) += k3-am642-phyboard-electra-gpio-fan.dtbo
 dtb-$(CONFIG_ARCH_K3) += k3-am642-phyboard-electra-pcie-usb2.dtbo
+dtb-$(CONFIG_ARCH_K3) += k3-am642-phyboard-electra-x27-gpio1-spi1-uart3.dtbo
 dtb-$(CONFIG_ARCH_K3) += k3-am642-sk.dtb
 dtb-$(CONFIG_ARCH_K3) += k3-am642-tqma64xxl-mbax4xxl.dtb
 dtb-$(CONFIG_ARCH_K3) += k3-am64-tqma64xxl-mbax4xxl-sdcard.dtbo
@@ -185,6 +186,8 @@ k3-am642-phyboard-electra-gpio-fan-dtbs := \
 	k3-am642-phyboard-electra-rdk.dtb k3-am642-phyboard-electra-gpio-fan.dtbo
 k3-am642-phyboard-electra-pcie-usb2-dtbs := \
 	k3-am642-phyboard-electra-rdk.dtb k3-am642-phyboard-electra-pcie-usb2.dtbo
+k3-am642-phyboard-electra-x27-gpio1-spi1-uart3-dtbs := \
+	k3-am642-phyboard-electra-rdk.dtb k3-am642-phyboard-electra-x27-gpio1-spi1-uart3.dtbo
 k3-am642-tqma64xxl-mbax4xxl-sdcard-dtbs := \
 	k3-am642-tqma64xxl-mbax4xxl.dtb k3-am64-tqma64xxl-mbax4xxl-sdcard.dtbo
 k3-am642-tqma64xxl-mbax4xxl-wlan-dtbs := \
diff --git a/arch/arm64/boot/dts/ti/k3-am642-phyboard-electra-x27-gpio1-spi1-uart3.dtso b/arch/arm64/boot/dts/ti/k3-am642-phyboard-electra-x27-gpio1-spi1-uart3.dtso
new file mode 100644
index 000000000000..996c42ec4253
--- /dev/null
+++ b/arch/arm64/boot/dts/ti/k3-am642-phyboard-electra-x27-gpio1-spi1-uart3.dtso
@@ -0,0 +1,63 @@
+// SPDX-License-Identifier: GPL-2.0-only OR MIT
+/*
+ * Copyright (C) 2025 PHYTEC Messtechnik GmbH
+ * Authors:
+ *   Wadim Egorov <w.egorov@phytec.de>
+ *   Daniel Schultz <d.schultz@phytec.de>
+ *
+ * GPIO, SPI and UART examples for the X27 expansion connector.
+ */
+
+/dts-v1/;
+/plugin/;
+
+#include "k3-pinctrl.h"
+
+&{/} {
+	aliases {
+		serial5 = "/bus@f4000/serial@2830000";
+	};
+};
+
+&main_pmx0 {
+	main_gpio1_exp_header_gpio_pins_default: main-gpio1-exp-header-gpio-pins-default {
+		pinctrl-single,pins = <
+			AM64X_IOPAD(0x0220, PIN_INPUT, 7)	/* (D14) SPI1_CS1.GPIO1_48 */
+		>;
+	};
+
+	main_spi1_pins_default: main-spi1-pins-default {
+		pinctrl-single,pins = <
+			AM64X_IOPAD(0x0224, PIN_INPUT, 0)	/* (C14) SPI1_CLK */
+			AM64X_IOPAD(0x021C, PIN_OUTPUT, 0)	/* (B14) SPI1_CS0 */
+			AM64X_IOPAD(0x0228, PIN_OUTPUT, 0)	/* (B15) SPI1_D0 */
+			AM64X_IOPAD(0x022C, PIN_INPUT, 0)	/* (A15) SPI1_D1 */
+		>;
+	};
+
+	main_uart3_pins_default: main-uart3-pins-default {
+		pinctrl-single,pins = <
+			AM64X_IOPAD(0x0048, PIN_INPUT, 2)       /* (U20) GPMC0_AD3.UART3_RXD */
+			AM64X_IOPAD(0x004c, PIN_OUTPUT, 2)      /* (U18) GPMC0_AD4.UART3_TXD */
+		>;
+	};
+};
+
+&main_gpio1 {
+	pinctrl-names = "default";
+	pinctrl-0 = <&main_gpio1_exp_header_gpio_pins_default>;
+	status = "okay";
+};
+
+&main_spi1 {
+	pinctrl-names = "default";
+	pinctrl-0 = <&main_spi1_pins_default>;
+	ti,pindir-d0-out-d1-in = <1>;
+	status = "okay";
+};
+
+&main_uart3 {
+	pinctrl-names = "default";
+	pinctrl-0 = <&main_uart3_pins_default>;
+	status = "okay";
+};
-- 
2.25.1