diff --git a/drivers/base/regmap/regmap-i2c.c b/drivers/base/regmap/regmap-i2c.c
index ac9b31c57967..6d934c35a770 100644
--- a/drivers/base/regmap/regmap-i2c.c
+++ b/drivers/base/regmap/regmap-i2c.c
@@ -242,8 +242,8 @@ static int regmap_i2c_smbus_i2c_read(void *context, const void *reg,
 static struct regmap_bus regmap_i2c_smbus_i2c_block = {
 	.write = regmap_i2c_smbus_i2c_write,
 	.read = regmap_i2c_smbus_i2c_read,
-	.max_raw_read = I2C_SMBUS_BLOCK_MAX,
-	.max_raw_write = I2C_SMBUS_BLOCK_MAX,
+	.max_raw_read = I2C_SMBUS_BLOCK_MAX - 1,
+	.max_raw_write = I2C_SMBUS_BLOCK_MAX - 1,
 };
 
 static const struct regmap_bus *regmap_get_i2c_bus(struct i2c_client *i2c,