[PATCH 8/8] arm64: dts: freescale: imx8mm-verdin: Add Cortex-M4F UART_4 overlay
From: Ernest Van Hoecke
Date: Mon Jul 13 2026 - 11:16:43 EST
From: Ernest Van Hoecke <ernest.vanhoecke@xxxxxxxxxxx>
Verdin UART_4 can be assigned to Cortex-M4F firmware. Add an overlay
that marks the UART as reserved so Linux does not claim the port.
The overlay is also combined with the Verdin iMX8M Mini Development
Board device tree to provide a ready-to-use DTB for the WiFi SoM
variant.
Signed-off-by: Ernest Van Hoecke <ernest.vanhoecke@xxxxxxxxxxx>
---
arch/arm64/boot/dts/freescale/Makefile | 3 +++
arch/arm64/boot/dts/freescale/imx8mm-verdin-uart4-mcu.dtso | 14 ++++++++++++++
2 files changed, 17 insertions(+)
diff --git a/arch/arm64/boot/dts/freescale/Makefile b/arch/arm64/boot/dts/freescale/Makefile
index ed3d678e7c5e..605008d7fe6e 100644
--- a/arch/arm64/boot/dts/freescale/Makefile
+++ b/arch/arm64/boot/dts/freescale/Makefile
@@ -193,6 +193,7 @@ dtb-$(CONFIG_ARCH_MXC) += imx8mm-verdin-ov5640-24mhz.dtbo
dtb-$(CONFIG_ARCH_MXC) += imx8mm-verdin-ov5640.dtbo
dtb-$(CONFIG_ARCH_MXC) += imx8mm-verdin-panel-cap-touch-10inch-dsi.dtbo
dtb-$(CONFIG_ARCH_MXC) += imx8mm-verdin-panel-cap-touch-7inch-dsi.dtbo
+dtb-$(CONFIG_ARCH_MXC) += imx8mm-verdin-uart4-mcu.dtbo
dtb-$(CONFIG_ARCH_MXC) += imx8mm-verdin-wifi-dahlia-dsi-to-hdmi.dtb
dtb-$(CONFIG_ARCH_MXC) += imx8mm-verdin-wifi-dahlia-panel-cap-touch-10inch-dsi.dtb
dtb-$(CONFIG_ARCH_MXC) += imx8mm-verdin-wifi-dahlia.dtb
@@ -202,6 +203,7 @@ dtb-$(CONFIG_ARCH_MXC) += imx8mm-verdin-wifi-dev-nau8822-btl.dtb
dtb-$(CONFIG_ARCH_MXC) += imx8mm-verdin-wifi-dev-ov5640-24mhz.dtb
dtb-$(CONFIG_ARCH_MXC) += imx8mm-verdin-wifi-dev-ov5640.dtb
dtb-$(CONFIG_ARCH_MXC) += imx8mm-verdin-wifi-dev-panel-cap-touch-7inch-dsi.dtb
+dtb-$(CONFIG_ARCH_MXC) += imx8mm-verdin-wifi-dev-uart4-mcu.dtb
dtb-$(CONFIG_ARCH_MXC) += imx8mm-verdin-wifi-dev.dtb
dtb-$(CONFIG_ARCH_MXC) += imx8mm-verdin-wifi-ivy.dtb
dtb-$(CONFIG_ARCH_MXC) += imx8mm-verdin-wifi-mallow.dtb
@@ -225,6 +227,7 @@ imx8mm-verdin-wifi-dev-ov5640-24mhz-dtbs := imx8mm-verdin-wifi-dev.dtb imx8mm-ve
imx8mm-verdin-wifi-dev-ov5640-dtbs := imx8mm-verdin-wifi-dev.dtb imx8mm-verdin-ov5640.dtbo
imx8mm-verdin-wifi-dev-panel-cap-touch-7inch-dsi-dtbs := imx8mm-verdin-wifi-dev.dtb \
imx8mm-verdin-panel-cap-touch-7inch-dsi.dtbo
+imx8mm-verdin-wifi-dev-uart4-mcu-dtbs := imx8mm-verdin-wifi-dev.dtb imx8mm-verdin-uart4-mcu.dtbo
imx8mm-verdin-wifi-yavia-dsi-to-hdmi-dtbs := imx8mm-verdin-wifi-yavia.dtb imx8mm-verdin-dsi-to-hdmi.dtbo
imx8mm-tqma8mqml-mba8mx-lvds-g133han01-dtbs += imx8mm-tqma8mqml-mba8mx.dtb imx8mm-tqma8mqml-mba8mx-lvds-g133han01.dtbo
diff --git a/arch/arm64/boot/dts/freescale/imx8mm-verdin-uart4-mcu.dtso b/arch/arm64/boot/dts/freescale/imx8mm-verdin-uart4-mcu.dtso
new file mode 100644
index 000000000000..8dbecffe9e7b
--- /dev/null
+++ b/arch/arm64/boot/dts/freescale/imx8mm-verdin-uart4-mcu.dtso
@@ -0,0 +1,14 @@
+// SPDX-License-Identifier: GPL-2.0-or-later OR MIT
+/*
+ * Copyright (c) Toradex
+ *
+ * Verdin iMX8M Mini UART_4 for Cortex-M4F
+ */
+
+/dts-v1/;
+/plugin/;
+
+/* Verdin UART_4 */
+&uart4 {
+ status = "reserved";
+};
--
2.43.0