diff --git a/arch/arm/boot/dts/nuvoton-npcm750-runbmc.dts b/arch/arm/boot/dts/nuvoton-npcm750-runbmc.dts
index e46015c56d24..35ce793d0238 100644
--- a/arch/arm/boot/dts/nuvoton-npcm750-runbmc.dts
+++ b/arch/arm/boot/dts/nuvoton-npcm750-runbmc.dts
@@ -624,6 +624,410 @@
 	};
 };
 
+/* external io expander */
+
+&i2c10 {
+	gpio: pca9555@4e {
+		compatible = "nxp,pca9555";
+		reg = <0x27>;
+		gpio-controller;
+		#gpio-cells = <2>;
+	};
+};
+
+&i2c11 {
+	pca9539_g1a: pca9539-g1a@74 {
+		compatible = "nxp,pca9539";
+		reg = <0x74>;
+		gpio-controller;
+		#gpio-cells = <2>;
+		reset-gpios = <&gpio7 4 GPIO_ACTIVE_LOW>;
+		G1A_P0_0 {
+			gpio-hog;
+			gpios = <0 0>;
+			output-high;
+			line-name = "TPM_BMC_ALERT_N";
+		};
+		G1A_P0_1 {
+			gpio-hog;
+			gpios = <1 0>;
+			input;
+			line-name = "FM_BIOS_TOP_SWAP";
+		};
+		G1A_P0_2 {
+			gpio-hog;
+			gpios = <2 0>;
+			input;
+			line-name = "FM_BIOS_PREFRB2_GOOD";
+		};
+		G1A_P0_3 {
+			gpio-hog;
+			gpios = <3 0>;
+			input;
+			line-name = "BMC_SATAXPCIE_0TO3_SEL";
+		};
+		G1A_P0_4 {
+			gpio-hog;
+			gpios = <4 0>;
+			input;
+			line-name = "BMC_SATAXPCIE_4TO7_SEL";
+		};
+		G1A_P0_5 {
+			gpio-hog;
+			gpios = <5 0>;
+			output-low;
+			line-name = "FM_UV_ADR_TRIGGER_EN_N";
+		};
+		G1A_P0_6 {
+			gpio-hog;
+			gpios = <6 0>;
+			input;
+			line-name = "RM_THROTTLE_EN_N";
+		};
+		G1A_P1_0 {
+			gpio-hog;
+			gpios = <8 0>;
+			input;
+			line-name = "FM_BMC_TPM_PRES_N";
+		};
+		G1A_P1_1 {
+			gpio-hog;
+			gpios = <9 0>;
+			input;
+			line-name = "FM_CPU0_SKTOCC_LVT3_N";
+		};
+		G1A_P1_2 {
+			gpio-hog;
+			gpios = <10 0>;
+			input;
+			line-name = "FM_CPU1_SKTOCC_LVT3_N";
+		};
+		G1A_P1_3 {
+			gpio-hog;
+			gpios = <11 0>;
+			input;
+			line-name = "PSU1_ALERT_N";
+		};
+		G1A_P1_4 {
+			gpio-hog;
+			gpios = <12 0>;
+			input;
+			line-name = "PSU2_ALERT_N";
+		};
+		G1A_P1_5 {
+			gpio-hog;
+			gpios = <13 0>;
+			input;
+			line-name = "H_CPU0_FAST_WAKE_LVT3_N";
+		};
+		G1A_P1_6 {
+			gpio-hog;
+			gpios = <14 0>;
+			output-high;
+			line-name = "I2C_MUX1_RESET_N";
+		};
+		G1A_P1_7 {
+			gpio-hog;
+			gpios = <15 0>;
+			input;
+			line-name = "FM_CPU_CATERR_LVT3_N";
+		};
+	};
+	pca9539_g1b: pca9539-g1b@75 {
+		compatible = "nxp,pca9539";
+		reg = <0x75>;
+		gpio-controller;
+		#gpio-cells = <2>;
+		G1B_P0_0 {
+			gpio-hog;
+			gpios = <0 0>;
+			input;
+			line-name = "PVDDQ_ABC_PINALERT_N";
+		};
+		G1B_P0_1 {
+			gpio-hog;
+			gpios = <1 0>;
+			input;
+			line-name = "PVDDQ_DEF_PINALERT_N";
+		};
+		G1B_P0_2 {
+			gpio-hog;
+			gpios = <2 0>;
+			input;
+			line-name = "PVDDQ_GHJ_PINALERT_N";
+		};
+		G1B_P0_3 {
+			gpio-hog;
+			gpios = <3 0>;
+			input;
+			line-name = "PVDDQ_KLM_PINALERT_N";
+		};
+		G1B_P0_5 {
+			gpio-hog;
+			gpios = <5 0>;
+			input;
+			line-name = "FM_BOARD_REV_ID0";
+		};
+		G1B_P0_6 {
+			gpio-hog;
+			gpios = <6 0>;
+			input;
+			line-name = "FM_BOARD_REV_ID1";
+		};
+		G1B_P0_7 {
+			gpio-hog;
+			gpios = <7 0>;
+			input;
+			line-name = "FM_BOARD_REV_ID2";
+		};
+		G1B_P1_0 {
+			gpio-hog;
+			gpios = <8 0>;
+			input;
+			line-name = "FM_OC_DETECT_EN_N";
+		};
+		G1B_P1_1 {
+			gpio-hog;
+			gpios = <9 0>;
+			input;
+			line-name = "FM_FLASH_DESC_OVERRIDE";
+		};
+		G1B_P1_2 {
+			gpio-hog;
+			gpios = <10 0>;
+			output-low;
+			line-name = "FP_PWR_ID_LED_N";
+		};
+		G1B_P1_3 {
+			gpio-hog;
+			gpios = <11 0>;
+			output-low;
+			line-name = "BMC_LED_PWR_GRN";
+		};
+		G1B_P1_4 {
+			gpio-hog;
+			gpios = <12 0>;
+			output-low;
+			line-name = "BMC_LED_PWR_AMBER";
+		};
+		G1B_P1_5 {
+			gpio-hog;
+			gpios = <13 0>;
+			output-high;
+			line-name = "FM_BMC_FAULT_LED_N";
+		};
+		G1B_P1_6 {
+			gpio-hog;
+			gpios = <14 0>;
+			output-high;
+			line-name = "FM_CPLD_BMC_PWRDN_N";
+		};
+		G1B_P1_7 {
+			gpio-hog;
+			gpios = <15 0>;
+			output-high;
+			line-name = "BMC_LED_CATERR_N";
+		};
+	};
+};
+
+&i2c12 {
+	pca9539_g2a: pca9539-g2a@74 {
+		compatible = "nxp,pca9539";
+		reg = <0x74>;
+		gpio-controller;
+		#gpio-cells = <2>;
+		reset-gpios = <&gpio5 28 GPIO_ACTIVE_LOW>;
+		G2A_P0_0 {
+			gpio-hog;
+			gpios = <0 0>;
+			output-high;
+			line-name = "BMC_PON_RST_REQ_N";
+		};
+		G2A_P0_1 {
+			gpio-hog;
+			gpios = <1 0>;
+			output-high;
+			line-name = "BMC_RST_IND_REQ_N";
+		};
+		G2A_P0_2 {
+			gpio-hog;
+			gpios = <2 0>;
+			input;
+			line-name = "RST_BMC_RTCRST";
+		};
+		G2A_P0_3 {
+			gpio-hog;
+			gpios = <3 0>;
+			output-high;
+			line-name = "FM_BMC_PWRBTN_OUT_N";
+		};
+		G2A_P0_4 {
+			gpio-hog;
+			gpios = <4 0>;
+			output-high;
+			line-name = "RST_BMC_SYSRST_BTN_OUT_N";
+		};
+		G2A_P0_5 {
+			gpio-hog;
+			gpios = <5 0>;
+			output-high;
+			line-name = "FM_BATTERY_SENSE_EN_N";
+		};
+		G2A_P0_6 {
+			gpio-hog;
+			gpios = <6 0>;
+			output-high;
+			line-name = "FM_BMC_READY_N";
+		};
+		G2A_P0_7 {
+			gpio-hog;
+			gpios = <7 0>;
+			input;
+			line-name = "IRQ_BMC_PCH_SMI_LPC_N";
+		};
+		G2A_P1_0 {
+			gpio-hog;
+			gpios = <8 0>;
+			input;
+			line-name = "FM_SLOT4_CFG0";
+		};
+		G2A_P1_1 {
+			gpio-hog;
+			gpios = <9 0>;
+			input;
+			line-name = "FM_SLOT4_CFG1";
+		};
+		G2A_P1_2 {
+			gpio-hog;
+			gpios = <10 0>;
+			input;
+			line-name = "FM_NVDIMM_EVENT_N";
+		};
+		G2A_P1_3 {
+			gpio-hog;
+			gpios = <11 0>;
+			input;
+			line-name = "PSU1_BLADE_EN_N";
+		};
+		G2A_P1_4 {
+			gpio-hog;
+			gpios = <12 0>;
+			input;
+			line-name = "BMC_PCH_FNM";
+		};
+		G2A_P1_5 {
+			gpio-hog;
+			gpios = <13 0>;
+			input;
+			line-name = "FM_SOL_UART_CH_SEL";
+		};
+		G2A_P1_6 {
+			gpio-hog;
+			gpios = <14 0>;
+			input;
+			line-name = "FM_BIOS_POST_CMPLT_N";
+		};
+	};
+
+	pca9539_g2b: pca9539-g2b@75 {
+		compatible = "nxp,pca9539";
+		reg = <0x75>;
+		gpio-controller;
+		#gpio-cells = <2>;
+		G2B_P0_0 {
+			gpio-hog;
+			gpios = <0 0>;
+			input;
+			line-name = "FM_CPU_MSMI_LVT3_N";
+		};
+		G2B_P0_1 {
+			gpio-hog;
+			gpios = <1 0>;
+			input;
+			line-name = "FM_BIOS_MRC_DEBUG_MSG_DIS";
+		};
+		G2B_P0_2 {
+			gpio-hog;
+			gpios = <2 0>;
+			input;
+			line-name = "FM_CPU1_DISABLE_BMC_N";
+		};
+		G2B_P0_3 {
+			gpio-hog;
+			gpios = <3 0>;
+			output-low;
+			line-name = "BMC_JTAG_SELECT";
+		};
+		G2B_P0_4 {
+			gpio-hog;
+			gpios = <4 0>;
+			output-high;
+			line-name = "PECI_MUX_SELECT";
+		};
+		G2B_P0_5 {
+			gpio-hog;
+			gpios = <5 0>;
+			output-high;
+			line-name = "I2C_MUX2_RESET_N";
+		};
+		G2B_P0_6 {
+			gpio-hog;
+			gpios = <6 0>;
+			input;
+			line-name = "FM_BMC_CPLD_PSU2_ON";
+		};
+		G2B_P0_7 {
+			gpio-hog;
+			gpios = <7 0>;
+			output-high;
+			line-name = "PSU2_ALERT_EN_N";
+		};
+		G2B_P1_0 {
+			gpio-hog;
+			gpios = <8 0>;
+			output-high;
+			line-name = "FM_CPU_BMC_INIT";
+		};
+		G2B_P1_1 {
+			gpio-hog;
+			gpios = <9 0>;
+			output-high;
+			line-name = "IRQ_BMC_PCH_SCI_LPC_N";
+		};
+		G2B_P1_2 {
+			gpio-hog;
+			gpios = <10 0>;
+			output-low;
+			line-name = "PMB_ALERT_EN_N";
+		};
+		G2B_P1_3 {
+			gpio-hog;
+			gpios = <11 0>;
+			output-high;
+			line-name = "FM_FAST_PROCHOT_EN_N";
+		};
+		G2B_P1_4 {
+			gpio-hog;
+			gpios = <12 0>;
+			output-high;
+			line-name = "BMC_NVDIMM_PRSNT_N";
+		};
+		G2B_P1_5 {
+			gpio-hog;
+			gpios = <13 0>;
+			output-low;
+			line-name = "FM_BACKUP_BIOS_SEL_H_BMC";
+		};
+		G2B_P1_6 {
+			gpio-hog;
+			gpios = <14 0>;
+			output-high;
+			line-name = "FM_PWRBRK_N";
+		};
+	};
+};
+
 &gcr {
 	serial_port_mux: mux-controller {
 	compatible = "mmio-mux";
