[PATCH v2 1/5] arm64: dts: freescale: imx8mm-verdin: Share the UART_4 MCU overlay

[Ernest Van Hoecke]

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

Verdin UART_4 is the UART the module assigns to the Cortex-M4F core.
Other Toradex modules also assign one UART to their Cortex-M core, such
as Verdin and Aquila UART_4 and SMARC SER0 on i.MX95, but on a different
UART instance, so an overlay naming the instance cannot be shared.

Label the UART uart_mcu in the module device tree and turn the Verdin
iMX8M Mini overlay into imx-tdx-uart-mcu.dtso, which reserves the
labelled UART. The combined Verdin iMX8M Mini DTB keeps its name.

Signed-off-by: Ernest Van Hoecke <ernest.vanhoecke at toradex.com>
---
 arch/arm64/boot/dts/freescale/Makefile                     |  5 +++--
 arch/arm64/boot/dts/freescale/imx-tdx-uart-mcu.dtso        | 14 ++++++++++++++
 arch/arm64/boot/dts/freescale/imx8mm-verdin-uart4-mcu.dtso | 14 --------------
 arch/arm64/boot/dts/freescale/imx8mm-verdin.dtsi           |  2 +-
 4 files changed, 18 insertions(+), 17 deletions(-)

diff --git a/arch/arm64/boot/dts/freescale/Makefile b/arch/arm64/boot/dts/freescale/Makefile
index a80cccf34eb5..a40bcbe4876d 100644
--- a/arch/arm64/boot/dts/freescale/Makefile
+++ b/arch/arm64/boot/dts/freescale/Makefile
@@ -107,6 +107,8 @@ dtb-$(CONFIG_ARCH_LAYERSCAPE) += fsl-lx2160a-tqmlx2160a-mblx2160a-14-11-x.dtb
 dtb-$(CONFIG_ARCH_LAYERSCAPE) += fsl-lx2160a-tqmlx2160a-mblx2160a-14-8-x.dtb
 dtb-$(CONFIG_ARCH_LAYERSCAPE) += fsl-lx2160a-tqmlx2160a-mblx2160a-14-7-x.dtb
 
+dtb-$(CONFIG_ARCH_MXC) += imx-tdx-uart-mcu.dtbo
+
 dtb-$(CONFIG_ARCH_MXC) += imx8dx-colibri-aster.dtb
 dtb-$(CONFIG_ARCH_MXC) += imx8dx-colibri-eval-v3.dtb
 dtb-$(CONFIG_ARCH_MXC) += imx8dx-colibri-iris-v2.dtb
@@ -268,7 +270,6 @@ dtb-$(CONFIG_ARCH_MXC) += imx8mm-verdin-nonwifi-yavia.dtb
 dtb-$(CONFIG_ARCH_MXC) += imx8mm-verdin-nonwifi-zinnia.dtb
 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
@@ -298,7 +299,7 @@ imx8mm-verdin-wifi-dev-dsi-to-lvds-panel-cap-touch-10inch-dtbs := imx8mm-verdin-
 imx8mm-verdin-wifi-dev-nau8822-btl-dtbs := imx8mm-verdin-wifi-dev.dtb imx8mm-verdin-dev-nau8822-btl.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-dev-uart4-mcu-dtbs := imx8mm-verdin-wifi-dev.dtb imx-tdx-uart-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/imx-tdx-uart-mcu.dtso b/arch/arm64/boot/dts/freescale/imx-tdx-uart-mcu.dtso
new file mode 100644
index 000000000000..001bc3286e8e
--- /dev/null
+++ b/arch/arm64/boot/dts/freescale/imx-tdx-uart-mcu.dtso
@@ -0,0 +1,14 @@
+// SPDX-License-Identifier: GPL-2.0-or-later OR MIT
+/*
+ * Copyright (c) Toradex
+ *
+ * Reserve the UART that the module assigns to its Cortex-M core, labelled
+ * uart_mcu in the module device tree, so that Linux does not claim it.
+ */
+
+/dts-v1/;
+/plugin/;
+
+&uart_mcu {
+	status = "reserved";
+};
diff --git a/arch/arm64/boot/dts/freescale/imx8mm-verdin-uart4-mcu.dtso b/arch/arm64/boot/dts/freescale/imx8mm-verdin-uart4-mcu.dtso
deleted file mode 100644
index 8dbecffe9e7b..000000000000
--- a/arch/arm64/boot/dts/freescale/imx8mm-verdin-uart4-mcu.dtso
+++ /dev/null
@@ -1,14 +0,0 @@
-// 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";
-};
diff --git a/arch/arm64/boot/dts/freescale/imx8mm-verdin.dtsi b/arch/arm64/boot/dts/freescale/imx8mm-verdin.dtsi
index 4f64c5da8d15..1ac9d000d415 100644
--- a/arch/arm64/boot/dts/freescale/imx8mm-verdin.dtsi
+++ b/arch/arm64/boot/dts/freescale/imx8mm-verdin.dtsi
@@ -776,7 +776,7 @@ &uart3 {
  * Verdin UART_4
  * Resource allocated to M4 by default, must not be accessed from Cortex-A35 or you get an OOPS
  */
-&uart4 {
+uart_mcu: &uart4 {
 	pinctrl-names = "default";
 	pinctrl-0 = <&pinctrl_uart4>;
 };

-- 
2.43.0