[PATCH v2 1/2] arm64: dts: st: move Engicam MicroGEA-STM32MP257D-RMM display to an overlay

[Dario Binacchi <dario.binacchi@amarulasolutions.com>]

The board is fitted with different displays depending on the product
variant. Keep in the board dts only what is common to all variants and
move the RK050HR345-CT106A RGB panel and its touchscreen to an overlay.

Signed-off-by: Dario Binacchi <dario.binacchi@amarulasolutions.com>
---

Changes in v2:
- Keep the full cs-gpios in the board dts, the overlay only adds the
  panel node. Suggested by Sashiko.

 arch/arm64/boot/dts/st/Makefile               |  6 ++
 ...icrogea-rmm-overlay-rk050hr345-ct106a.dtso | 68 +++++++++++++++++++
 .../st/stm32mp257d-engicam-microgea-rmm.dts   | 46 +------------
 3 files changed, 75 insertions(+), 45 deletions(-)
 create mode 100644 arch/arm64/boot/dts/st/stm32mp257d-engicam-microgea-rmm-overlay-rk050hr345-ct106a.dtso

diff --git a/arch/arm64/boot/dts/st/Makefile b/arch/arm64/boot/dts/st/Makefile
index 6cbccfd50993..218ff7fdf576 100644
--- a/arch/arm64/boot/dts/st/Makefile
+++ b/arch/arm64/boot/dts/st/Makefile
@@ -1,7 +1,13 @@
 # SPDX-License-Identifier: GPL-2.0-only
+stm32mp257d-engicam-microgea-rmm-overlay-rk050hr345-ct106a-dtbs := \
+	stm32mp257d-engicam-microgea-rmm.dtb \
+	stm32mp257d-engicam-microgea-rmm-overlay-rk050hr345-ct106a.dtbo
+
 dtb-$(CONFIG_ARCH_STM32) += \
 	stm32mp215f-dk.dtb \
 	stm32mp235f-dk.dtb \
 	stm32mp257d-engicam-microgea-rmm.dtb \
+	stm32mp257d-engicam-microgea-rmm-overlay-rk050hr345-ct106a.dtb \
+	stm32mp257d-engicam-microgea-rmm-overlay-rk050hr345-ct106a.dtbo \
 	stm32mp257f-dk.dtb \
 	stm32mp257f-ev1.dtb
diff --git a/arch/arm64/boot/dts/st/stm32mp257d-engicam-microgea-rmm-overlay-rk050hr345-ct106a.dtso b/arch/arm64/boot/dts/st/stm32mp257d-engicam-microgea-rmm-overlay-rk050hr345-ct106a.dtso
new file mode 100644
index 000000000000..f89641bdb23b
--- /dev/null
+++ b/arch/arm64/boot/dts/st/stm32mp257d-engicam-microgea-rmm-overlay-rk050hr345-ct106a.dtso
@@ -0,0 +1,68 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2026 Amarula Solutions, Dario Binacchi <dario.binacchi@amarulasolutions.com>
+ * Copyright (C) 2026 Engicam srl
+ *
+ * Rocktech RK050HR345-CT106A 5" 480x854 RGB panel with EDT FT5306
+ * I2C touchscreen controller.
+ */
+
+/dts-v1/;
+/plugin/;
+
+#include <dt-bindings/gpio/gpio.h>
+#include <dt-bindings/interrupt-controller/irq.h>
+
+&i2c1 {
+	pinctrl-names = "default", "sleep";
+	pinctrl-0 = <&i2c1_pins_a>;
+	pinctrl-1 = <&i2c1_sleep_pins_a>;
+	i2c-scl-rising-time-ns = <185>;
+	i2c-scl-falling-time-ns = <20>;
+	#address-cells = <1>;
+	#size-cells = <0>;
+	status = "okay";
+
+	touchscreen@38 {
+		compatible = "edt,edt-ft5306";
+		reg = <0x38>;
+		interrupt-parent = <&gpiob>;
+		interrupts = <0 IRQ_TYPE_EDGE_FALLING>;
+		reset-gpios = <&gpiod 1 GPIO_ACTIVE_LOW>;
+		touchscreen-size-x = <480>;
+		touchscreen-size-y = <854>;
+	};
+};
+
+&ltdc {
+	pinctrl-names = "default", "sleep";
+	pinctrl-0 = <&ltdc_pins_a>;
+	pinctrl-1 = <&ltdc_sleep_pins_a>;
+	status = "okay";
+
+	port {
+		ltdc_out: endpoint {
+			remote-endpoint = <&panel_in>;
+		};
+	};
+};
+
+&spi1 {
+	#address-cells = <1>;
+	#size-cells = <0>;
+
+	display@0 {
+		compatible = "rocktech,rk050hr345-ct106a", "ilitek,ili9806e";
+		reg = <0>;
+		vdd-supply = <&reg_3v3>;
+		spi-max-frequency = <10000000>;
+		reset-gpios = <&gpiob 6 GPIO_ACTIVE_LOW>;
+		backlight = <&backlight>;
+
+		port {
+			panel_in: endpoint {
+				remote-endpoint = <&ltdc_out>;
+			};
+		};
+	};
+};
diff --git a/arch/arm64/boot/dts/st/stm32mp257d-engicam-microgea-rmm.dts b/arch/arm64/boot/dts/st/stm32mp257d-engicam-microgea-rmm.dts
index f5af0913bf1b..faedddc2c914 100644
--- a/arch/arm64/boot/dts/st/stm32mp257d-engicam-microgea-rmm.dts
+++ b/arch/arm64/boot/dts/st/stm32mp257d-engicam-microgea-rmm.dts
@@ -116,25 +116,9 @@ &arm_wdt {
 };
 
 &i2c1 {
-	pinctrl-names = "default", "sleep";
-	pinctrl-0 = <&i2c1_pins_a>;
-	pinctrl-1 = <&i2c1_sleep_pins_a>;
-	i2c-scl-rising-time-ns = <185>;
-	i2c-scl-falling-time-ns = <20>;
-	status = "okay";
-	/* spare dmas for other usage */
+	/* dt overlays don't support /delete-property/ */
 	/delete-property/dmas;
 	/delete-property/dma-names;
-
-	touchscreen@38 {
-		compatible = "edt,edt-ft5306";
-		reg = <0x38>;
-		interrupt-parent = <&gpiob>;
-		interrupts = <0 IRQ_TYPE_EDGE_FALLING>;
-		reset-gpios = <&gpiod 1 GPIO_ACTIVE_LOW>;
-		touchscreen-size-x = <480>;
-		touchscreen-size-y = <854>;
-	};
 };
 
 &i2c2 {
@@ -179,19 +163,6 @@ sgtl5000_rx_endpoint: endpoint@1 {
 	};
 };
 
-&ltdc {
-	pinctrl-names = "default", "sleep";
-	pinctrl-0 = <&ltdc_pins_a>;
-	pinctrl-1 = <&ltdc_sleep_pins_a>;
-	status = "okay";
-
-	port {
-		ltdc_out: endpoint {
-			remote-endpoint = <&panel_in>;
-		};
-	};
-};
-
 &m_can1 {
 	pinctrl-names = "default", "sleep";
 	pinctrl-0 = <&m_can1_pins_a>;
@@ -259,21 +230,6 @@ &spi1 {
 	#size-cells = <0>;
 	cs-gpios = <&gpioh 8 GPIO_ACTIVE_LOW>, <&gpioh 3 GPIO_ACTIVE_HIGH>;
 	status = "okay";
-
-	display: display@0 {
-		compatible = "rocktech,rk050hr345-ct106a", "ilitek,ili9806e";
-		reg = <0>;
-		vdd-supply = <&reg_3v3>;
-		spi-max-frequency = <10000000>;
-		reset-gpios = <&gpiob 6 GPIO_ACTIVE_LOW>;
-		backlight = <&backlight>;
-
-		port {
-			panel_in: endpoint {
-				remote-endpoint = <&ltdc_out>;
-			};
-		};
-	};
 };
 
 &timers2 {
-- 
2.43.0