soc: silabs: Add support for Silabs EFR32ZG28 SoC

Add support for Silicon Labs EFR32ZG28 SoC.

Signed-off-by: Shontal Biton <shontal1005@gmail.com>

Author: shontal1005

dts/arm/silabs/xg28/efr32xg28.dtsi

@@ -0,0 +1,37 @@
+/*
+ * Copyright (c) 2025 Silicon Laboratories Inc.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <silabs/xg28/xg28.dtsi>
+
+/ {
+	soc {
+		radio: radio@b0000000 {
+			compatible = "silabs,series2-radio";
+			reg = <0xb0000000 0x1000000>;
+			interrupts = <31 1>, <32 1>, <33 1>, <34 1>, <35 1>, <36 1>,
+				     <37 1>, <38 1>, <39 1>, <40 1>, <74 1>, <75 1>;
+			interrupt-names = "agc", "bufc", "frc_pri", "frc", "modem", "protimer",
+					  "rac_rsm", "rac_seq", "hostmailbox", "synth",
+					  "rfeca0", "rfeca1";
+			pa-initial-power-dbm = <10>;
+			pa-ramp-time-us = <10>;
+			pa-voltage-mv = <3300>;
+			pa-subghz = "highest";
+
+			bt_hci_silabs: bt_hci_silabs {
+				compatible = "silabs,bt-hci-efr32";
+				status = "disabled";
+			};
+
+			pti: pti {
+				compatible = "silabs,pti";
+				clock-frequency = <DT_FREQ_K(1600)>;
+				mode = "uart";
+				status = "disabled";
+			};
+		};
+	};
+};

dts/arm/silabs/xg28/efr32zg28.dtsi

@@ -0,0 +1,7 @@
+/*
+ * Copyright (c) 2025 Silicon Laboratories Inc.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <silabs/xg28/efr32xg28.dtsi>

dts/arm/silabs/xg28/efr32zg28b322f1024im68.dtsi

@@ -0,0 +1,24 @@
+/*
+ * Copyright (c) 2025 Shontal Biton
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <mem.h>
+#include <silabs/xg28/efr32zg28.dtsi>
+
+/ {
+	sram0: memory@20000000 {
+		reg = <0x20000000 DT_SIZE_K(256)>;
+	};
+
+	soc {
+		compatible = "silabs,efr32zg28b322f1024im68",
+					 "silabs,efr32zg28", "silabs,efr32",
+					 "simple-bus";
+	};
+};
+
+&flash0 {
+	reg = <0x08000000 DT_SIZE_K(1024)>;
+};