diff --git a/Documentation/devicetree/bindings/regulator/mt6397-regulator.txt b/Documentation/devicetree/bindings/regulator/mt6397-regulator.txt
index 01141fb00875..c080086d3e62 100644
--- a/Documentation/devicetree/bindings/regulator/mt6397-regulator.txt
+++ b/Documentation/devicetree/bindings/regulator/mt6397-regulator.txt
@@ -16,6 +16,9 @@ LDO:
   ldo_vemc3v3, ldo_vgp1, ldo_vgp2, ldo_vgp3, ldo_vgp4, ldo_vgp5, ldo_vgp6,
   ldo_vibr
 
+BUCK regulators can set regulator-initial-mode and regulator-allowed-modes to
+values specified in dt-bindings/regulator/mediatek,mt6397-regulator.h
+
 Example:
 	pmic {
 		compatible = "mediatek,mt6397";
diff --git a/drivers/regulator/mt6397-regulator.c b/drivers/regulator/mt6397-regulator.c
index 269c2a6028e8..0a30df5e414f 100644
--- a/drivers/regulator/mt6397-regulator.c
+++ b/drivers/regulator/mt6397-regulator.c
@@ -13,9 +13,7 @@
 #include <linux/regulator/machine.h>
 #include <linux/regulator/mt6397-regulator.h>
 #include <linux/regulator/of_regulator.h>
-
-#define MT6397_BUCK_MODE_AUTO	0
-#define MT6397_BUCK_MODE_FORCE_PWM	1
+#include <dt-bindings/regulator/mediatek,mt6397-regulator.h>
 
 /*
  * MT6397 regulators' information
@@ -55,6 +53,7 @@ struct mt6397_regulator_info {
 		.vsel_mask = vosel_mask,				\
 		.enable_reg = enreg,					\
 		.enable_mask = BIT(0),					\
+		.of_map_mode = mt6397_map_mode,				\
 	},								\
 	.qi = BIT(13),							\
 	.vselon_reg = voselon,						\
@@ -146,6 +145,18 @@ static const unsigned int ldo_volt_table7[] = {
 	1300000, 1500000, 1800000, 2000000, 2500000, 2800000, 3000000, 3300000,
 };
 
+static unsigned int mt6397_map_mode(unsigned int mode)
+{
+	switch (mode) {
+	case MT6397_BUCK_MODE_AUTO:
+		return REGULATOR_MODE_NORMAL;
+	case MT6397_BUCK_MODE_FORCE_PWM:
+		return REGULATOR_MODE_FAST;
+	default:
+		return REGULATOR_MODE_INVALID;
+	}
+}
+
 static int mt6397_regulator_set_mode(struct regulator_dev *rdev,
 				     unsigned int mode)
 {
diff --git a/include/dt-bindings/regulator/mediatek,mt6397-regulator.h b/include/dt-bindings/regulator/mediatek,mt6397-regulator.h
new file mode 100644
index 000000000000..99869a8665cf
--- /dev/null
+++ b/include/dt-bindings/regulator/mediatek,mt6397-regulator.h
@@ -0,0 +1,15 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef _DT_BINDINGS_REGULATOR_MEDIATEK_MT6397_H_
+#define _DT_BINDINGS_REGULATOR_MEDIATEK_MT6397_H_
+
+/*
+ * Buck mode constants which may be used in devicetree properties (eg.
+ * regulator-initial-mode, regulator-allowed-modes).
+ * See the manufacturer's datasheet for more information on these modes.
+ */
+
+#define MT6397_BUCK_MODE_AUTO		0
+#define MT6397_BUCK_MODE_FORCE_PWM	1
+
+#endif