[PATCH 3/4] arm64: dts: freescale: imx95-aquila: Add Cortex-M7 UART_4 overlay

[Ernest Van Hoecke]

From: Ernest Van Hoecke <ernest.vanhoecke at toradex.com>

Aquila UART_4 can be assigned to Cortex-M7 firmware. Add an overlay
that reserves LPUART2 so Linux does not claim the port. Firmware must
configure the UART and its pads for the intended MCU application.

The overlay is also combined with the Aquila iMX95 Development Board
device tree to provide a ready-to-use DTB.

Signed-off-by: Ernest Van Hoecke <ernest.vanhoecke at toradex.com>
---
 arch/arm64/boot/dts/freescale/Makefile                    |  4 ++++
 arch/arm64/boot/dts/freescale/imx95-aquila-uart4-mcu.dtso | 14 ++++++++++++++
 2 files changed, 18 insertions(+)

diff --git a/arch/arm64/boot/dts/freescale/Makefile b/arch/arm64/boot/dts/freescale/Makefile
index c283c582d974..b17fd5b067de 100644
--- a/arch/arm64/boot/dts/freescale/Makefile
+++ b/arch/arm64/boot/dts/freescale/Makefile
@@ -954,7 +954,9 @@ dtb-$(CONFIG_ARCH_MXC) += imx95-19x19-evk.dtb
 dtb-$(CONFIG_ARCH_MXC) += imx95-19x19-evk-sof.dtb
 dtb-$(CONFIG_ARCH_MXC) += imx95-19x19-frdm-pro.dtb
 dtb-$(CONFIG_ARCH_MXC) += imx95-aquila-clover.dtb
+dtb-$(CONFIG_ARCH_MXC) += imx95-aquila-dev-uart4-mcu.dtb
 dtb-$(CONFIG_ARCH_MXC) += imx95-aquila-dev.dtb
+dtb-$(CONFIG_ARCH_MXC) += imx95-aquila-uart4-mcu.dtbo
 dtb-$(CONFIG_ARCH_MXC) += imx95-toradex-smarc-dev.dtb
 dtb-$(CONFIG_ARCH_MXC) += imx95-tqma9596la-mba95xxca.dtb
 dtb-$(CONFIG_ARCH_MXC) += imx95-tqma9596sa-mb-smarc-2.dtb
@@ -976,6 +978,8 @@ dtb-$(CONFIG_ARCH_MXC) += imx95-verdin-wifi-mallow.dtb
 dtb-$(CONFIG_ARCH_MXC) += imx95-verdin-wifi-yavia.dtb
 dtb-$(CONFIG_ARCH_MXC) += imx95-verdin-wifi-zinnia.dtb
 
+imx95-aquila-dev-uart4-mcu-dtbs := imx95-aquila-dev.dtb imx95-aquila-uart4-mcu.dtbo
+
 imx95-verdin-wifi-dev-nau8822-btl-dtbs := imx95-verdin-wifi-dev.dtb imx95-verdin-dev-nau8822-btl.dtbo
 imx95-verdin-wifi-dev-uart4-mcu-dtbs := imx95-verdin-wifi-dev.dtb imx95-verdin-uart4-mcu.dtbo
 
diff --git a/arch/arm64/boot/dts/freescale/imx95-aquila-uart4-mcu.dtso b/arch/arm64/boot/dts/freescale/imx95-aquila-uart4-mcu.dtso
new file mode 100644
index 000000000000..140025af4d53
--- /dev/null
+++ b/arch/arm64/boot/dts/freescale/imx95-aquila-uart4-mcu.dtso
@@ -0,0 +1,14 @@
+// SPDX-License-Identifier: GPL-2.0-only OR MIT
+/*
+ * Copyright (c) Toradex
+ *
+ * Aquila iMX95 UART_4 for Cortex-M7
+ */
+
+/dts-v1/;
+/plugin/;
+
+/* Aquila UART_4 */
+&lpuart2 {
+	status = "reserved";
+};

-- 
2.43.0