diff --git a/drivers/mfd/rsmu.h b/drivers/mfd/rsmu.h
index bb88597d189f..1bb04cafa45d 100644
--- a/drivers/mfd/rsmu.h
+++ b/drivers/mfd/rsmu.h
@@ -10,6 +10,8 @@
 
 #include <linux/mfd/rsmu.h>
 
+#define RSMU_CM_SCSR_BASE		0x20100000
+
 int rsmu_core_init(struct rsmu_ddata *rsmu);
 void rsmu_core_exit(struct rsmu_ddata *rsmu);
 
diff --git a/drivers/mfd/rsmu_i2c.c b/drivers/mfd/rsmu_i2c.c
index 15d25b081434..221023faaadf 100644
--- a/drivers/mfd/rsmu_i2c.c
+++ b/drivers/mfd/rsmu_i2c.c
@@ -18,11 +18,12 @@
 #include "rsmu.h"
 
 /*
- * 16-bit register address: the lower 8 bits of the register address come
- * from the offset addr byte and the upper 8 bits come from the page register.
+ * 32-bit register address: the lower 8 bits of the register address come
+ * from the offset addr byte and the upper 24 bits come from the page register.
  */
-#define	RSMU_CM_PAGE_ADDR		0xFD
-#define	RSMU_CM_PAGE_WINDOW		256
+#define	RSMU_CM_PAGE_ADDR		0xFC
+#define RSMU_CM_PAGE_MASK		0xFFFFFF00
+#define RSMU_CM_ADDRESS_MASK		0x000000FF
 
 /*
  * 15-bit register address: the lower 7 bits of the register address come
@@ -31,18 +32,6 @@
 #define	RSMU_SABRE_PAGE_ADDR		0x7F
 #define	RSMU_SABRE_PAGE_WINDOW		128
 
-static const struct regmap_range_cfg rsmu_cm_range_cfg[] = {
-	{
-		.range_min = 0,
-		.range_max = 0xD000,
-		.selector_reg = RSMU_CM_PAGE_ADDR,
-		.selector_mask = 0xFF,
-		.selector_shift = 0,
-		.window_start = 0,
-		.window_len = RSMU_CM_PAGE_WINDOW,
-	}
-};
-
 static const struct regmap_range_cfg rsmu_sabre_range_cfg[] = {
 	{
 		.range_min = 0,
@@ -55,16 +44,6 @@ static const struct regmap_range_cfg rsmu_sabre_range_cfg[] = {
 	}
 };
 
-static bool rsmu_cm_volatile_reg(struct device *dev, unsigned int reg)
-{
-	switch (reg) {
-	case RSMU_CM_PAGE_ADDR:
-		return false;
-	default:
-		return true;
-	}
-}
-
 static bool rsmu_sabre_volatile_reg(struct device *dev, unsigned int reg)
 {
 	switch (reg) {
@@ -75,15 +54,131 @@ static bool rsmu_sabre_volatile_reg(struct device *dev, unsigned int reg)
 	}
 }
 
+static int rsmu_read_device(struct rsmu_ddata *rsmu, u8 reg, u8 *buf, u16 bytes)
+{
+	struct i2c_client *client = to_i2c_client(rsmu->dev);
+	struct i2c_msg msg[2];
+	int cnt;
+
+	msg[0].addr = client->addr;
+	msg[0].flags = 0;
+	msg[0].len = 1;
+	msg[0].buf = &reg;
+
+	msg[1].addr = client->addr;
+	msg[1].flags = I2C_M_RD;
+	msg[1].len = bytes;
+	msg[1].buf = buf;
+
+	cnt = i2c_transfer(client->adapter, msg, 2);
+
+	if (cnt < 0) {
+		dev_err(rsmu->dev, "i2c_transfer failed at addr: %04x!", reg);
+		return cnt;
+	} else if (cnt != 2) {
+		dev_err(rsmu->dev,
+			"i2c_transfer sent only %d of 2 messages", cnt);
+		return -EIO;
+	}
+
+	return 0;
+}
+
+static int rsmu_write_device(struct rsmu_ddata *rsmu, u8 reg, u8 *buf, u16 bytes)
+{
+	struct i2c_client *client = to_i2c_client(rsmu->dev);
+	u8 msg[RSMU_MAX_WRITE_COUNT + 1]; /* 1 Byte added for the device register */
+	int cnt;
+
+	if (bytes > RSMU_MAX_WRITE_COUNT)
+		return -EINVAL;
+
+	msg[0] = reg;
+	memcpy(&msg[1], buf, bytes);
+
+	cnt = i2c_master_send(client, msg, bytes + 1);
+
+	if (cnt < 0) {
+		dev_err(&client->dev,
+			"i2c_master_send failed at addr: %04x!", reg);
+		return cnt;
+	}
+
+	return 0;
+}
+
+static int rsmu_write_page_register(struct rsmu_ddata *rsmu, u32 reg)
+{
+	u32 page = reg & RSMU_CM_PAGE_MASK;
+	u8 buf[4];
+	int err;
+
+	/* Do not modify offset register for none-scsr registers */
+	if (reg < RSMU_CM_SCSR_BASE)
+		return 0;
+
+	/* Simply return if we are on the same page */
+	if (rsmu->page == page)
+		return 0;
+
+	buf[0] = 0x0;
+	buf[1] = (u8)((page >> 8) & 0xFF);
+	buf[2] = (u8)((page >> 16) & 0xFF);
+	buf[3] = (u8)((page >> 24) & 0xFF);
+
+	err = rsmu_write_device(rsmu, RSMU_CM_PAGE_ADDR, buf, sizeof(buf));
+	if (err)
+		dev_err(rsmu->dev, "Failed to set page offset 0x%x\n", page);
+	else
+		/* Remember the last page */
+		rsmu->page = page;
+
+	return err;
+}
+
+static int rsmu_reg_read(void *context, unsigned int reg, unsigned int *val)
+{
+	struct rsmu_ddata *rsmu = i2c_get_clientdata((struct i2c_client *)context);
+	u8 addr = (u8)(reg & RSMU_CM_ADDRESS_MASK);
+	int err;
+
+	err = rsmu_write_page_register(rsmu, reg);
+	if (err)
+		return err;
+
+	err = rsmu_read_device(rsmu, addr, (u8 *)val, 1);
+	if (err)
+		dev_err(rsmu->dev, "Failed to read offset address 0x%x\n", addr);
+
+	return err;
+}
+
+static int rsmu_reg_write(void *context, unsigned int reg, unsigned int val)
+{
+	struct rsmu_ddata *rsmu = i2c_get_clientdata((struct i2c_client *)context);
+	u8 addr = (u8)(reg & RSMU_CM_ADDRESS_MASK);
+	u8 data = (u8)val;
+	int err;
+
+	err = rsmu_write_page_register(rsmu, reg);
+	if (err)
+		return err;
+
+	err = rsmu_write_device(rsmu, addr, &data, 1);
+	if (err)
+		dev_err(rsmu->dev,
+			"Failed to write offset address 0x%x\n", addr);
+
+	return err;
+}
+
 static const struct regmap_config rsmu_cm_regmap_config = {
-	.reg_bits = 8,
+	.reg_bits = 32,
 	.val_bits = 8,
-	.max_register = 0xD000,
-	.ranges = rsmu_cm_range_cfg,
-	.num_ranges = ARRAY_SIZE(rsmu_cm_range_cfg),
-	.volatile_reg = rsmu_cm_volatile_reg,
-	.cache_type = REGCACHE_RBTREE,
-	.can_multi_write = true,
+	.max_register = 0x20120000,
+	.reg_read = rsmu_reg_read,
+	.reg_write = rsmu_reg_write,
+	.cache_type = REGCACHE_NONE,
 };
 
 static const struct regmap_config rsmu_sabre_regmap_config = {
@@ -101,14 +196,14 @@ static const struct regmap_config rsmu_sl_regmap_config = {
 	.reg_bits = 16,
 	.val_bits = 8,
 	.reg_format_endian = REGMAP_ENDIAN_BIG,
-	.max_register = 0x339,
+	.max_register = 0x340,
 	.cache_type = REGCACHE_NONE,
 	.can_multi_write = true,
 };
 
-static int rsmu_i2c_probe(struct i2c_client *client)
+static int rsmu_i2c_probe(struct i2c_client *client,
+			  const struct i2c_device_id *id)
 {
-	const struct i2c_device_id *id = i2c_client_get_device_id(client);
 	const struct regmap_config *cfg;
 	struct rsmu_ddata *rsmu;
 	int ret;
@@ -136,7 +231,11 @@ static int rsmu_i2c_probe(struct i2c_client *client)
 		dev_err(rsmu->dev, "Unsupported RSMU device type: %d\n", rsmu->type);
 		return -ENODEV;
 	}
-	rsmu->regmap = devm_regmap_init_i2c(client, cfg);
+
+	if (rsmu->type == RSMU_CM)
+		rsmu->regmap = devm_regmap_init(&client->dev, NULL, client, cfg);
+	else
+		rsmu->regmap = devm_regmap_init_i2c(client, cfg);
 	if (IS_ERR(rsmu->regmap)) {
 		ret = PTR_ERR(rsmu->regmap);
 		dev_err(rsmu->dev, "Failed to allocate register map: %d\n", ret);
@@ -180,7 +279,7 @@ static struct i2c_driver rsmu_i2c_driver = {
 		.name = "rsmu-i2c",
 		.of_match_table = of_match_ptr(rsmu_i2c_of_match),
 	},
-	.probe_new = rsmu_i2c_probe,
+	.probe = rsmu_i2c_probe,
 	.remove	= rsmu_i2c_remove,
 	.id_table = rsmu_i2c_id,
 };
diff --git a/drivers/mfd/rsmu_spi.c b/drivers/mfd/rsmu_spi.c
index 2428aaa9aaed..a4a595bb8d0d 100644
--- a/drivers/mfd/rsmu_spi.c
+++ b/drivers/mfd/rsmu_spi.c
@@ -19,19 +19,21 @@
 
 #define	RSMU_CM_PAGE_ADDR		0x7C
 #define	RSMU_SABRE_PAGE_ADDR		0x7F
-#define	RSMU_HIGHER_ADDR_MASK		0xFF80
-#define	RSMU_HIGHER_ADDR_SHIFT		7
-#define	RSMU_LOWER_ADDR_MASK		0x7F
+#define	RSMU_PAGE_MASK			0xFFFFFF80
+#define	RSMU_ADDR_MASK			0x7F
 
 static int rsmu_read_device(struct rsmu_ddata *rsmu, u8 reg, u8 *buf, u16 bytes)
 {
 	struct spi_device *client = to_spi_device(rsmu->dev);
 	struct spi_transfer xfer = {0};
 	struct spi_message msg;
-	u8 cmd[256] = {0};
-	u8 rsp[256] = {0};
+	u8 cmd[RSMU_MAX_READ_COUNT + 1] = {0};
+	u8 rsp[RSMU_MAX_READ_COUNT + 1] = {0};
 	int ret;
 
+	if (bytes > RSMU_MAX_READ_COUNT)
+		return -EINVAL;
+
 	cmd[0] = reg | 0x80;
 	xfer.rx_buf = rsp;
 	xfer.len = bytes + 1;
@@ -66,7 +68,10 @@ static int rsmu_write_device(struct rsmu_ddata *rsmu, u8 reg, u8 *buf, u16 bytes
 	struct spi_device *client = to_spi_device(rsmu->dev);
 	struct spi_transfer xfer = {0};
 	struct spi_message msg;
-	u8 cmd[256] = {0};
+	u8 cmd[RSMU_MAX_WRITE_COUNT + 1] = {0};
+
+	if (bytes > RSMU_MAX_WRITE_COUNT)
+		return -EINVAL;
 
 	cmd[0] = reg;
 	memcpy(&cmd[1], buf, bytes);
@@ -86,26 +91,35 @@ static int rsmu_write_device(struct rsmu_ddata *rsmu, u8 reg, u8 *buf, u16 bytes
  * 16-bit register address: the lower 7 bits of the register address come
  * from the offset addr byte and the upper 9 bits come from the page register.
  */
-static int rsmu_write_page_register(struct rsmu_ddata *rsmu, u16 reg)
+static int rsmu_write_page_register(struct rsmu_ddata *rsmu, u32 reg)
 {
 	u8 page_reg;
-	u8 buf[2];
+	u8 buf[4];
 	u16 bytes;
-	u16 page;
+	u32 page;
 	int err;
 
 	switch (rsmu->type) {
 	case RSMU_CM:
+		/* Do not modify page register for none-scsr registers */
+		if (reg < RSMU_CM_SCSR_BASE)
+			return 0;
 		page_reg = RSMU_CM_PAGE_ADDR;
-		page = reg & RSMU_HIGHER_ADDR_MASK;
+		page = reg & RSMU_PAGE_MASK;
 		buf[0] = (u8)(page & 0xff);
 		buf[1] = (u8)((page >> 8) & 0xff);
-		bytes = 2;
+		buf[2] = (u8)((page >> 16) & 0xff);
+		buf[3] = (u8)((page >> 24) & 0xff);
+		bytes = 4;
 		break;
 	case RSMU_SABRE:
+		/* Do not modify page register if reg is page register itself */
+		if ((reg & RSMU_ADDR_MASK) == RSMU_ADDR_MASK)
+			return 0;
 		page_reg = RSMU_SABRE_PAGE_ADDR;
-		page = reg >> RSMU_HIGHER_ADDR_SHIFT;
-		buf[0] = (u8)(page & 0xff);
+		page = reg & RSMU_PAGE_MASK;
+		/* The three page bits are located in the single Page Register */
+		buf[0] = (u8)((page >> 7) & 0x7);
 		bytes = 1;
 		break;
 	default:
@@ -129,8 +143,8 @@ static int rsmu_write_page_register(struct rsmu_ddata *rsmu, u16 reg)
 
 static int rsmu_reg_read(void *context, unsigned int reg, unsigned int *val)
 {
-	struct rsmu_ddata *rsmu = spi_get_drvdata(context);
-	u8 addr = (u8)(reg & RSMU_LOWER_ADDR_MASK);
+	struct rsmu_ddata *rsmu = spi_get_drvdata((struct spi_device *)context);
+	u8 addr = (u8)(reg & RSMU_ADDR_MASK);
 	int err;
 
 	err = rsmu_write_page_register(rsmu, reg);
@@ -146,8 +160,8 @@ static int rsmu_reg_read(void *context, unsigned int reg, unsigned int *val)
 
 static int rsmu_reg_write(void *context, unsigned int reg, unsigned int val)
 {
-	struct rsmu_ddata *rsmu = spi_get_drvdata(context);
-	u8 addr = (u8)(reg & RSMU_LOWER_ADDR_MASK);
+	struct rsmu_ddata *rsmu = spi_get_drvdata((struct spi_device *)context);
+	u8 addr = (u8)(reg & RSMU_ADDR_MASK);
 	u8 data = (u8)val;
 	int err;
 
@@ -164,9 +178,9 @@ static int rsmu_reg_write(void *context, unsigned int reg, unsigned int val)
 }
 
 static const struct regmap_config rsmu_cm_regmap_config = {
-	.reg_bits = 16,
+	.reg_bits = 32,
 	.val_bits = 8,
-	.max_register = 0xD000,
+	.max_register = 0x20120000,
 	.reg_read = rsmu_reg_read,
 	.reg_write = rsmu_reg_write,
 	.cache_type = REGCACHE_NONE,
diff --git a/include/linux/mfd/rsmu.h b/include/linux/mfd/rsmu.h
index 6870de608233..0379aa207428 100644
--- a/include/linux/mfd/rsmu.h
+++ b/include/linux/mfd/rsmu.h
@@ -8,6 +8,9 @@
 #ifndef __LINUX_MFD_RSMU_H
 #define __LINUX_MFD_RSMU_H
 
+#define RSMU_MAX_WRITE_COUNT	(255)
+#define RSMU_MAX_READ_COUNT	(255)
+
 /* The supported devices are ClockMatrix, Sabre and SnowLotus */
 enum rsmu_type {
 	RSMU_CM		= 0x34000,
@@ -31,6 +34,6 @@ struct rsmu_ddata {
 	struct regmap *regmap;
 	struct mutex lock;
 	enum rsmu_type type;
-	u16 page;
+	u32 page;
 };
 #endif /*  __LINUX_MFD_RSMU_H */