diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index 6aa2c4b9a65a..02ed1546da21 100644
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -37,6 +37,11 @@ struct regmap {
 	void *work_buf;     /* Scratch buffer used to format I/O */
 	struct regmap_format format;  /* Buffer format */
 	const struct regmap_bus *bus;
+
+	unsigned int max_register;
+	bool (*writeable_reg)(struct device *dev, unsigned int reg);
+	bool (*readable_reg)(struct device *dev, unsigned int reg);
+	bool (*volatile_reg)(struct device *dev, unsigned int reg);
 };
 
 static void regmap_format_4_12_write(struct regmap *map,
@@ -116,6 +121,10 @@ struct regmap *regmap_init(struct device *dev,
 	map->format.val_bytes = config->val_bits / 8;
 	map->dev = dev;
 	map->bus = bus;
+	map->max_register = config->max_register;
+	map->writeable_reg = config->writeable_reg;
+	map->readable_reg = config->readable_reg;
+	map->volatile_reg = config->volatile_reg;
 
 	switch (config->reg_bits) {
 	case 4:
@@ -323,7 +332,7 @@ static int _regmap_raw_read(struct regmap *map, unsigned int reg, void *val,
 		u8[0] |= map->bus->read_flag_mask;
 
 	ret = map->bus->read(map->dev, map->work_buf, map->format.reg_bytes,
-			     val, map->format.val_bytes);
+			     val, val_len);
 	if (ret != 0)
 		return ret;
 
diff --git a/include/linux/regmap.h b/include/linux/regmap.h
index 60a65cd7e1a0..c878a4bf717e 100644
--- a/include/linux/regmap.h
+++ b/include/linux/regmap.h
@@ -20,9 +20,32 @@
 struct i2c_client;
 struct spi_device;
 
+/**
+ * Configuration for the register map of a device.
+ *
+ * @reg_bits: Number of bits in a register address, mandatory.
+ * @val_bits: Number of bits in a register value, mandatory.
+ *
+ * @max_register: Optional, specifies the maximum valid register index.
+ * @writeable_register: Optional callback returning true if the register
+ *                      can be written to.
+ * @readable_register: Optional callback returning true if the register
+ *                     can be read from.
+ * @volatile_register: Optional callback returning true if the register
+ *                     value can't be cached.
+ * @precious_register: Optional callback returning true if the rgister
+ *                     should not be read outside of a call from the driver
+ *                     (eg, a clear on read interrupt status register).
+ */
 struct regmap_config {
 	int reg_bits;
 	int val_bits;
+
+	unsigned int max_register;
+	bool (*writeable_reg)(struct device *dev, unsigned int reg);
+	bool (*readable_reg)(struct device *dev, unsigned int reg);
+	bool (*volatile_reg)(struct device *dev, unsigned int reg);
+	bool (*precious_reg)(struct device *dev, unsigned int reg);
 };
 
 typedef int (*regmap_hw_write)(struct device *dev, const void *data,