[PATCH v6 14/16] arm64: dts: st: support Engicam MicroGEA-STM32MP257 SoM

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

Support Engicam MicroGEA-STM32MP257 SoM with:

 - 8 GB eMMC Flash
 - 2 GB LPDDR4 DRAM

The SoM also provides an Ethernet MAC, but Ethernet support is not
enabled at this stage due to a known silicon limitation documented in
[1].

This corresponds to section 2.21.2 ("ETH1 RMII mode could have CRC
errors"), where CRC errors may occur in ETH1 RMII direct mode when
directly connected to I/Os.

The workaround requires use of the Ethernet switch (ETHSW), which
introduces additional DT bindings and topology complexity. This is
intended to be addressed in a separate patch series.

[1] https://www.st.com/resource/en/errata_sheet/es0598-stm32mp23xx25xx-device-errata-stmicroelectronics.pdf
Signed-off-by: Dario Binacchi <dario.binacchi@amarulasolutions.com>

---

(no changes since v4)

Changes in v4:
- Drop inclusion of stm32mp25xf.dtsi, we are using stm32mp257d.

Changes in v3:
- Fix a typo in the URL

 .../dts/st/stm32mp257-engicam-microgea.dtsi   | 63 +++++++++++++++++++
 1 file changed, 63 insertions(+)
 create mode 100644 arch/arm64/boot/dts/st/stm32mp257-engicam-microgea.dtsi

diff --git a/arch/arm64/boot/dts/st/stm32mp257-engicam-microgea.dtsi b/arch/arm64/boot/dts/st/stm32mp257-engicam-microgea.dtsi
new file mode 100644
index 000000000000..5b4287e86def
--- /dev/null
+++ b/arch/arm64/boot/dts/st/stm32mp257-engicam-microgea.dtsi
@@ -0,0 +1,63 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2026 Amarula Solutions, Dario Binacchi <dario.binacchi@amarulasolutions.com>
+ * Copyright (C) 2026 Engicam srl
+ */
+
+/dts-v1/;
+
+#include <dt-bindings/regulator/st,stm32mp25-regulator.h>
+#include "stm32mp257.dtsi"
+#include "stm32mp25-pinctrl.dtsi"
+#include "stm32mp25xxai-pinctrl.dtsi"
+
+/ {
+	model = "Engicam MicroGEA STM32MP257 SoM";
+	compatible = "engicam,microgea-stm32mp257", "st,stm32mp257";
+
+	memory@80000000 {
+		device_type = "memory";
+		reg = <0x0 0x80000000 0x0 0x80000000>;
+	};
+};
+
+&scmi_regu {
+	scmi_vddio1: regulator@0 {
+		regulator-min-microvolt = <3300000>;
+		regulator-max-microvolt = <3300000>;
+	};
+	scmi_vddcore: regulator@b {
+		reg = <VOLTD_SCMI_STPMIC2_BUCK2>;
+		regulator-name = "vddcore";
+	};
+	scmi_v1v8: regulator@e {
+		reg = <VOLTD_SCMI_STPMIC2_BUCK5>;
+		regulator-name = "v1v8";
+	};
+	scmi_v3v3: regulator@10 {
+		reg = <VOLTD_SCMI_STPMIC2_BUCK7>;
+		regulator-name = "v3v3";
+	};
+	scmi_vdd3v3_usb: regulator@14 {
+		reg = <VOLTD_SCMI_STPMIC2_LDO4>;
+		regulator-name = "vdd3v3_usb";
+	};
+};
+
+/* eMMC */
+&sdmmc2 {
+	pinctrl-names = "default", "opendrain", "sleep";
+	pinctrl-0 = <&sdmmc2_b4_pins_a &sdmmc2_d47_pins_a>;
+	pinctrl-1 = <&sdmmc2_b4_od_pins_a &sdmmc2_d47_pins_a>;
+	pinctrl-2 = <&sdmmc2_b4_sleep_pins_a &sdmmc2_d47_sleep_pins_a>;
+	non-removable;
+	no-sd;
+	no-sdio;
+	st,neg-edge;
+	bus-width = <8>;
+	vmmc-supply = <&scmi_v3v3>;
+	vqmmc-supply = <&scmi_vddio2>;
+	mmc-ddr-1_8v;
+	mmc-hs200-1_8v;
+	status = "okay";
+};
-- 
2.43.0