diff --git a/drivers/base/regmap/regmap-mmio.c b/drivers/base/regmap/regmap-mmio.c
index 8a77876d439a..3db8625261e0 100644
--- a/drivers/base/regmap/regmap-mmio.c
+++ b/drivers/base/regmap/regmap-mmio.c
@@ -25,26 +25,14 @@
 
 struct regmap_mmio_context {
 	void __iomem *regs;
-	unsigned reg_bytes;
 	unsigned val_bytes;
-	unsigned pad_bytes;
 	struct clk *clk;
-};
 
-static inline void regmap_mmio_regsize_check(size_t reg_size)
-{
-	switch (reg_size) {
-	case 1:
-	case 2:
-	case 4:
-#ifdef CONFIG_64BIT
-	case 8:
-#endif
-		break;
-	default:
-		BUG();
-	}
-}
+	void (*reg_write)(struct regmap_mmio_context *ctx,
+			  unsigned int reg, unsigned int val);
+	unsigned int (*reg_read)(struct regmap_mmio_context *ctx,
+			         unsigned int reg);
+};
 
 static int regmap_mmio_regbits_check(size_t reg_bits)
 {
@@ -61,72 +49,62 @@ static int regmap_mmio_regbits_check(size_t reg_bits)
 	}
 }
 
-static inline void regmap_mmio_count_check(size_t count, u32 offset)
+static void regmap_mmio_write8(struct regmap_mmio_context *ctx,
+				unsigned int reg,
+				unsigned int val)
 {
-	BUG_ON(count <= offset);
+	writeb(val, ctx->regs + reg);
 }
 
-static inline unsigned int
-regmap_mmio_get_offset(const void *reg, size_t reg_size)
+static void regmap_mmio_write16le(struct regmap_mmio_context *ctx,
+				  unsigned int reg,
+				  unsigned int val)
 {
-	switch (reg_size) {
-	case 1:
-		return *(u8 *)reg;
-	case 2:
-		return *(u16 *)reg;
-	case 4:
-		return *(u32 *)reg;
-#ifdef CONFIG_64BIT
-	case 8:
-		return *(u64 *)reg;
-#endif
-	default:
-		BUG();
-	}
+	writew(val, ctx->regs + reg);
 }
 
-static int regmap_mmio_gather_write(void *context,
-				    const void *reg, size_t reg_size,
-				    const void *val, size_t val_size)
+static void regmap_mmio_write16be(struct regmap_mmio_context *ctx,
+				  unsigned int reg,
+				  unsigned int val)
+{
+	iowrite16be(val, ctx->regs + reg);
+}
+
+static void regmap_mmio_write32le(struct regmap_mmio_context *ctx,
+				  unsigned int reg,
+				  unsigned int val)
+{
+	writel(val, ctx->regs + reg);
+}
+
+static void regmap_mmio_write32be(struct regmap_mmio_context *ctx,
+				  unsigned int reg,
+				  unsigned int val)
+{
+	iowrite32be(val, ctx->regs + reg);
+}
+
+#ifdef __64BIT
+static void regmap_mmio_write64le(struct regmap_mmio_context *ctx,
+				  unsigned int reg,
+				  unsigned int val)
+{
+	writeq(val, ctx->regs + reg);
+}
+#endif
+
+static int regmap_mmio_write(void *context, unsigned int reg, unsigned int val)
 {
 	struct regmap_mmio_context *ctx = context;
-	unsigned int offset;
 	int ret;
 
-	regmap_mmio_regsize_check(reg_size);
-
 	if (!IS_ERR(ctx->clk)) {
 		ret = clk_enable(ctx->clk);
 		if (ret < 0)
 			return ret;
 	}
 
-	offset = regmap_mmio_get_offset(reg, reg_size);
-
-	while (val_size) {
-		switch (ctx->val_bytes) {
-		case 1:
-			__raw_writeb(*(u8 *)val, ctx->regs + offset);
-			break;
-		case 2:
-			__raw_writew(*(u16 *)val, ctx->regs + offset);
-			break;
-		case 4:
-			__raw_writel(*(u32 *)val, ctx->regs + offset);
-			break;
-#ifdef CONFIG_64BIT
-		case 8:
-			__raw_writeq(*(u64 *)val, ctx->regs + offset);
-			break;
-#endif
-		default:
-			/* Should be caught by regmap_mmio_check_config */
-			BUG();
-		}
-		val_size -= ctx->val_bytes;
-		val += ctx->val_bytes;
-		offset += ctx->val_bytes;
-	}
+	ctx->reg_write(ctx, reg, val);
 
 	if (!IS_ERR(ctx->clk))
 		clk_disable(ctx->clk);
@@ -134,59 +112,56 @@ static int regmap_mmio_gather_write(void *context,
 	return 0;
 }
 
-static int regmap_mmio_write(void *context, const void *data, size_t count)
+static unsigned int regmap_mmio_read8(struct regmap_mmio_context *ctx,
+				      unsigned int reg)
 {
-	struct regmap_mmio_context *ctx = context;
-	unsigned int offset = ctx->reg_bytes + ctx->pad_bytes;
+	return readb(ctx->regs + reg);
+}
+
+static unsigned int regmap_mmio_read16le(struct regmap_mmio_context *ctx,
+				         unsigned int reg)
+{
+	return readw(ctx->regs + reg);
+}
 
-	regmap_mmio_count_check(count, offset);
+static unsigned int regmap_mmio_read16be(struct regmap_mmio_context *ctx,
+				         unsigned int reg)
+{
+	return ioread16be(ctx->regs + reg);
+}
+
+static unsigned int regmap_mmio_read32le(struct regmap_mmio_context *ctx,
+				         unsigned int reg)
+{
+	return readw(ctx->regs + reg);
+}
 
-	return regmap_mmio_gather_write(context, data, ctx->reg_bytes,
-					data + offset, count - offset);
+static unsigned int regmap_mmio_read32be(struct regmap_mmio_context *ctx,
+				         unsigned int reg)
+{
+	return ioread32be(ctx->regs + reg);
 }
 
-static int regmap_mmio_read(void *context,
-			    const void *reg, size_t reg_size,
-			    void *val, size_t val_size)
+#ifdef __64BIT
+static unsigned int regmap_mmio_read64le(struct regmap_mmio_context *ctx,
+				         unsigned int reg)
+{
+	return readq(ctx->regs + reg);
+}
+#endif
+
+static int regmap_mmio_read(void *context, unsigned int reg, unsigned int *val)
 {
 	struct regmap_mmio_context *ctx = context;
-	unsigned int offset;
 	int ret;
 
-	regmap_mmio_regsize_check(reg_size);
-
 	if (!IS_ERR(ctx->clk)) {
 		ret = clk_enable(ctx->clk);
 		if (ret < 0)
 			return ret;
 	}
 
-	offset = regmap_mmio_get_offset(reg, reg_size);
-
-	while (val_size) {
-		switch (ctx->val_bytes) {
-		case 1:
-			*(u8 *)val = __raw_readb(ctx->regs + offset);
-			break;
-		case 2:
-			*(u16 *)val = __raw_readw(ctx->regs + offset);
-			break;
-		case 4:
-			*(u32 *)val = __raw_readl(ctx->regs + offset);
-			break;
-#ifdef CONFIG_64BIT
-		case 8:
-			*(u64 *)val = __raw_readq(ctx->regs + offset);
-			break;
-#endif
-		default:
-			/* Should be caught by regmap_mmio_check_config */
-			BUG();
-		}
-		val_size -= ctx->val_bytes;
-		val += ctx->val_bytes;
-		offset += ctx->val_bytes;
-	}
+	*val = ctx->reg_read(ctx, reg);
 
 	if (!IS_ERR(ctx->clk))
 		clk_disable(ctx->clk);
@@ -205,14 +180,11 @@ static void regmap_mmio_free_context(void *context)
 	kfree(context);
 }
 
-static struct regmap_bus regmap_mmio = {
+static const struct regmap_bus regmap_mmio = {
 	.fast_io = true,
-	.write = regmap_mmio_write,
-	.gather_write = regmap_mmio_gather_write,
-	.read = regmap_mmio_read,
+	.reg_write = regmap_mmio_write,
+	.reg_read = regmap_mmio_read,
 	.free_context = regmap_mmio_free_context,
-	.reg_format_endian_default = REGMAP_ENDIAN_NATIVE,
-	.val_format_endian_default = REGMAP_ENDIAN_NATIVE,
 };
 
 static struct regmap_mmio_context *regmap_mmio_gen_context(struct device *dev,
@@ -255,24 +227,71 @@ static struct regmap_mmio_context *regmap_mmio_gen_context(struct device *dev,
 	if (config->reg_stride < min_stride)
 		return ERR_PTR(-EINVAL);
 
-	switch (config->reg_format_endian) {
-	case REGMAP_ENDIAN_DEFAULT:
-	case REGMAP_ENDIAN_NATIVE:
-		break;
-	default:
-		return ERR_PTR(-EINVAL);
-	}
-
 	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
 	if (!ctx)
 		return ERR_PTR(-ENOMEM);
 
 	ctx->regs = regs;
 	ctx->val_bytes = config->val_bits / 8;
-	ctx->reg_bytes = config->reg_bits / 8;
-	ctx->pad_bytes = config->pad_bits / 8;
 	ctx->clk = ERR_PTR(-ENODEV);
 
+	switch (config->reg_format_endian) {
+	case REGMAP_ENDIAN_DEFAULT:
+	case REGMAP_ENDIAN_LITTLE:
+#ifdef __LITTLE_ENDIAN
+	case REGMAP_ENDIAN_NATIVE:
+#endif
+		switch (config->val_bits) {
+		case 8:
+			ctx->reg_read = regmap_mmio_read8;
+			ctx->reg_write = regmap_mmio_write8;
+			break;
+		case 16:
+			ctx->reg_read = regmap_mmio_read16le;
+			ctx->reg_write = regmap_mmio_write16le;
+			break;
+		case 32:
+			ctx->reg_read = regmap_mmio_read32le;
+			ctx->reg_write = regmap_mmio_write32le;
+			break;
+#ifdef __64BIT
+		case 64:
+			ctx->reg_read = regmap_mmio_read64le;
+			ctx->reg_write = regmap_mmio_write64le;
+			break;
+#endif
+		default:
+			ret = -EINVAL;
+			goto err_free;
+		}
+		break;
+	case REGMAP_ENDIAN_BIG:
+#ifdef __BIG_ENDIAN
+	case REGMAP_ENDIAN_NATIVE:
+#endif
+		switch (config->val_bits) {
+		case 8:
+			ctx->reg_read = regmap_mmio_read8;
+			ctx->reg_write = regmap_mmio_write8;
+			break;
+		case 16:
+			ctx->reg_read = regmap_mmio_read16be;
+			ctx->reg_write = regmap_mmio_write16be;
+			break;
+		case 32:
+			ctx->reg_read = regmap_mmio_read32be;
+			ctx->reg_write = regmap_mmio_write32be;
+			break;
+		default:
+			ret = -EINVAL;
+			goto err_free;
+		}
+		break;
+	default:
+		ret = -EINVAL;
+		goto err_free;
+	}
+
 	if (clk_id == NULL)
 		return ctx;
 
