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

Hi Daniel Schultz,

On Tue, 28 Jan 2025 02:03:56 -0800, Daniel Schultz wrote:
> 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.
> 
> [...]

I have applied the following to branch ti-k3-dts-next on [1].
Thank you!

[1/1] arm64: dts: ti: am64-phyboard-electra: Add DT overlay for X27 connector
      commit: 638ab30ce4c63edae4934dcaa7a61f37b96efe6c

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent up the chain during
the next merge window (or sooner if it is a relevant bug fix), however if
problems are discovered then the patch may be dropped or reverted.

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

[1] https://git.kernel.org/pub/scm/linux/kernel/git/ti/linux.git
--
Vignesh