diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
index 5b9891b2be6c..29b9ab528774 100644
--- a/drivers/iommu/mtk_iommu.c
+++ b/drivers/iommu/mtk_iommu.c
@@ -358,8 +358,8 @@ static irqreturn_t mtk_iommu_isr(int irq, void *dev_id)
 	return IRQ_HANDLED;
 }
 
-static int mtk_iommu_get_domain_id(struct device *dev,
-				   const struct mtk_iommu_plat_data *plat_data)
+static int mtk_iommu_get_iova_region_id(struct device *dev,
+					const struct mtk_iommu_plat_data *plat_data)
 {
 	const struct mtk_iommu_iova_region *rgn = plat_data->iova_region;
 	const struct bus_dma_region *dma_rgn = dev->dma_range_map;
@@ -389,7 +389,7 @@ static int mtk_iommu_get_domain_id(struct device *dev,
 }
 
 static int mtk_iommu_config(struct mtk_iommu_data *data, struct device *dev,
-			    bool enable, unsigned int domid)
+			    bool enable, unsigned int regionid)
 {
 	struct mtk_smi_larb_iommu    *larb_mmu;
 	unsigned int                 larbid, portid;
@@ -405,12 +405,12 @@ static int mtk_iommu_config(struct mtk_iommu_data *data, struct device *dev,
 		if (MTK_IOMMU_IS_TYPE(data->plat_data, MTK_IOMMU_TYPE_MM)) {
 			larb_mmu = &data->larb_imu[larbid];
 
-			region = data->plat_data->iova_region + domid;
+			region = data->plat_data->iova_region + regionid;
 			larb_mmu->bank[portid] = upper_32_bits(region->iova_base);
 
-			dev_dbg(dev, "%s iommu for larb(%s) port %d dom %d bank %d.\n",
+			dev_dbg(dev, "%s iommu for larb(%s) port %d region %d rgn-bank %d.\n",
 				enable ? "enable" : "disable", dev_name(larb_mmu->dev),
-				portid, domid, larb_mmu->bank[portid]);
+				portid, regionid, larb_mmu->bank[portid]);
 
 			if (enable)
 				larb_mmu->mmu |= MTK_SMI_MMU_EN(portid);
@@ -437,7 +437,7 @@ static int mtk_iommu_config(struct mtk_iommu_data *data, struct device *dev,
 
 static int mtk_iommu_domain_finalise(struct mtk_iommu_domain *dom,
 				     struct mtk_iommu_data *data,
-				     unsigned int domid)
+				     unsigned int region_id)
 {
 	const struct mtk_iommu_iova_region *region;
 	struct mtk_iommu_domain	*m4u_dom;
@@ -476,7 +476,7 @@ static int mtk_iommu_domain_finalise(struct mtk_iommu_domain *dom,
 
 update_iova_region:
 	/* Update the iova region for this domain */
-	region = data->plat_data->iova_region + domid;
+	region = data->plat_data->iova_region + region_id;
 	dom->domain.geometry.aperture_start = region->iova_base;
 	dom->domain.geometry.aperture_end = region->iova_base + region->size - 1;
 	dom->domain.geometry.force_aperture = true;
@@ -517,18 +517,18 @@ static int mtk_iommu_attach_device(struct iommu_domain *domain,
 	struct mtk_iommu_bank_data *bank;
 	struct device *m4udev = data->dev;
 	unsigned int bankid = 0;
-	int ret, domid;
+	int ret, region_id;
 
-	domid = mtk_iommu_get_domain_id(dev, data->plat_data);
-	if (domid < 0)
-		return domid;
+	region_id = mtk_iommu_get_iova_region_id(dev, data->plat_data);
+	if (region_id < 0)
+		return region_id;
 
 	bank = &data->bank[bankid];
 	if (!dom->bank) {
 		/* Data is in the frstdata in sharing pgtable case. */
 		frstdata = mtk_iommu_get_frst_data(hw_list);
 
-		if (mtk_iommu_domain_finalise(dom, frstdata, domid))
+		if (mtk_iommu_domain_finalise(dom, frstdata, region_id))
 			return -ENODEV;
 		dom->bank = bank;
 	}
@@ -550,7 +550,7 @@ static int mtk_iommu_attach_device(struct iommu_domain *domain,
 		pm_runtime_put(m4udev);
 	}
 
-	return mtk_iommu_config(data, dev, true, domid);
+	return mtk_iommu_config(data, dev, true, region_id);
 }
 
 static void mtk_iommu_detach_device(struct iommu_domain *domain,
@@ -653,21 +653,21 @@ static struct iommu_group *mtk_iommu_device_group(struct device *dev)
 	struct mtk_iommu_data *c_data = dev_iommu_priv_get(dev), *data;
 	struct list_head *hw_list = c_data->hw_list;
 	struct iommu_group *group;
-	int domid;
+	int regionid;
 
 	data = mtk_iommu_get_frst_data(hw_list);
 	if (!data)
 		return ERR_PTR(-ENODEV);
 
-	domid = mtk_iommu_get_domain_id(dev, data->plat_data);
-	if (domid < 0)
-		return ERR_PTR(domid);
+	regionid = mtk_iommu_get_iova_region_id(dev, data->plat_data);
+	if (regionid < 0)
+		return ERR_PTR(regionid);
 
-	group = data->m4u_group[domid];
+	group = data->m4u_group[regionid];
 	if (!group) {
 		group = iommu_group_alloc();
 		if (!IS_ERR(group))
-			data->m4u_group[domid] = group;
+			data->m4u_group[regionid] = group;
 	} else {
 		iommu_group_ref_get(group);
 	}
@@ -700,14 +700,14 @@ static void mtk_iommu_get_resv_regions(struct device *dev,
 				       struct list_head *head)
 {
 	struct mtk_iommu_data *data = dev_iommu_priv_get(dev);
-	unsigned int domid = mtk_iommu_get_domain_id(dev, data->plat_data), i;
+	unsigned int regionid = mtk_iommu_get_iova_region_id(dev, data->plat_data), i;
 	const struct mtk_iommu_iova_region *resv, *curdom;
 	struct iommu_resv_region *region;
 	int prot = IOMMU_WRITE | IOMMU_READ;
 
-	if ((int)domid < 0)
+	if ((int)regionid < 0)
 		return;
-	curdom = data->plat_data->iova_region + domid;
+	curdom = data->plat_data->iova_region + regionid;
 	for (i = 0; i < data->plat_data->iova_region_nr; i++) {
 		resv = data->plat_data->iova_region + i;
 
