diff --git a/drivers/pinctrl/nuvoton/pinctrl-npcm8xx.c b/drivers/pinctrl/nuvoton/pinctrl-npcm8xx.c
index c859dca4b973..1d5b3c648109 100644
--- a/drivers/pinctrl/nuvoton/pinctrl-npcm8xx.c
+++ b/drivers/pinctrl/nuvoton/pinctrl-npcm8xx.c
@@ -26,6 +26,7 @@
 #define NPCM8XX_GCR_SRCNT	0x068
 #define NPCM8XX_GCR_FLOCKR1	0x074
 #define NPCM8XX_GCR_DSCNT	0x078
+#define NPCM8XX_GCR_INTCR4	0x0c0
 #define NPCM8XX_GCR_I2CSEGSEL	0x0e0
 #define NPCM8XX_GCR_MFSEL1	0x260
 #define NPCM8XX_GCR_MFSEL2	0x264
@@ -78,6 +79,9 @@
 #define NPCM8XX_GPIO_PER_BANK	32
 #define NPCM8XX_GPIO_BANK_NUM	8
 #define NPCM8XX_GCR_NONE	0
+#define NPCM8XX_INTCR4_R1_RMII_EN	BIT(12)
+#define NPCM8XX_INTCR4_R2_RMII_EN	BIT(13)
+#define NPCM8XX_INTCR4_RMII3_EN	BIT(14)
 
 #define NPCM8XX_DEBOUNCE_MAX		4
 #define NPCM8XX_DEBOUNCE_NSEC		40
@@ -1796,6 +1800,61 @@ static const struct pinctrl_pin_desc npcm8xx_pins[] = {
 	PINCTRL_PIN(251, "JM2/CP1_GPIO"),
 	};
 
+static u32 npcm8xx_rmii_output_enable_mask(unsigned int pin)
+{
+	switch (pin) {
+	case 178:
+	case 179:
+	case 180:
+	case 181:
+	case 182:
+	case 193:
+	case 201:
+		return NPCM8XX_INTCR4_R1_RMII_EN;
+	case 84:
+	case 85:
+	case 86:
+	case 87:
+	case 88:
+	case 89:
+	case 200:
+		return NPCM8XX_INTCR4_R2_RMII_EN;
+	case 110:
+	case 111:
+	case 209:
+	case 210:
+	case 211:
+	case 214:
+	case 215:
+		return NPCM8XX_INTCR4_RMII3_EN;
+	default:
+		return 0;
+	}
+}
+
+static void npcm8xx_set_rmii_output_enable(struct regmap *gcr_regmap,
+					   const unsigned int *pin,
+					   int pin_number, int mode)
+{
+	u32 mask = 0;
+	u32 val = 0;
+	u32 bit;
+	int i;
+
+	for (i = 0; i < pin_number; i++) {
+		bit = npcm8xx_rmii_output_enable_mask(pin[i]);
+		mask |= bit;
+
+		if ((mode == fn_r1 && bit == NPCM8XX_INTCR4_R1_RMII_EN) ||
+		    (mode == fn_r2 && bit == NPCM8XX_INTCR4_R2_RMII_EN) ||
+		    (mode == fn_rmii3 && bit == NPCM8XX_INTCR4_RMII3_EN))
+			val |= bit;
+	}
+
+	if (mask)
+		regmap_update_bits(gcr_regmap, NPCM8XX_GCR_INTCR4, mask, val);
+}
+
 /* Enable mode in pin group */
 static void npcm8xx_setfunc(struct regmap *gcr_regmap, const unsigned int *pin,
 			    int pin_number, int mode)
@@ -1834,6 +1893,8 @@ static void npcm8xx_setfunc(struct regmap *gcr_regmap, const unsigned int *pin,
 						   BIT(cfg->bit4) : 0);
 		}
 	}
+
+	npcm8xx_set_rmii_output_enable(gcr_regmap, pin, pin_number, mode);
 }
 
 static int npcm8xx_get_slew_rate(struct npcm8xx_gpio *bank,