diff --git a/drivers/base/regmap/internal.h b/drivers/base/regmap/internal.h
index 70ca270b77e2..5a22bd33ce3d 100644
--- a/drivers/base/regmap/internal.h
+++ b/drivers/base/regmap/internal.h
@@ -91,6 +91,8 @@ struct regmap {
 	int (*reg_read)(void *context, unsigned int reg, unsigned int *val);
 	int (*reg_write)(void *context, unsigned int reg, unsigned int val);
 
+	bool defer_caching;
+
 	u8 read_flag_mask;
 	u8 write_flag_mask;
 
diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index b1d962434cb2..3d2367501fd0 100644
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -389,7 +389,7 @@ struct regmap *regmap_init(struct device *dev,
 	enum regmap_endian reg_endian, val_endian;
 	int i, j;
 
-	if (!bus || !config)
+	if (!config)
 		goto err;
 
 	map = kzalloc(sizeof(*map), GFP_KERNEL);
@@ -403,7 +403,8 @@ struct regmap *regmap_init(struct device *dev,
 		map->unlock = config->unlock;
 		map->lock_arg = config->lock_arg;
 	} else {
-		if (bus->fast_io) {
+		if ((bus && bus->fast_io) ||
+		    config->fast_io) {
 			spin_lock_init(&map->spinlock);
 			map->lock = regmap_lock_spinlock;
 			map->unlock = regmap_unlock_spinlock;
@@ -447,11 +448,19 @@ struct regmap *regmap_init(struct device *dev,
 	if (config->read_flag_mask || config->write_flag_mask) {
 		map->read_flag_mask = config->read_flag_mask;
 		map->write_flag_mask = config->write_flag_mask;
-	} else {
+	} else if (bus) {
 		map->read_flag_mask = bus->read_flag_mask;
 	}
 
-	map->reg_read = _regmap_bus_read;
+	if (!bus) {
+		map->reg_read  = config->reg_read;
+		map->reg_write = config->reg_write;
+
+		map->defer_caching = false;
+		goto skip_format_initialization;
+	} else {
+		map->reg_read  = _regmap_bus_read;
+	}
 
 	reg_endian = config->reg_format_endian;
 	if (reg_endian == REGMAP_ENDIAN_DEFAULT)
@@ -604,10 +613,15 @@ struct regmap *regmap_init(struct device *dev,
 		goto err_map;
 	}
 
-	if (map->format.format_write)
+	if (map->format.format_write) {
+		map->defer_caching = false;
 		map->reg_write = _regmap_bus_formatted_write;
-	else if (map->format.format_val)
+	} else if (map->format.format_val) {
+		map->defer_caching = true;
 		map->reg_write = _regmap_bus_raw_write;
+	}
+
+skip_format_initialization:
 
 	map->range_tree = RB_ROOT;
 	for (i = 0; i < config->num_ranges; i++) {
@@ -810,7 +824,7 @@ void regmap_exit(struct regmap *map)
 	regcache_exit(map);
 	regmap_debugfs_exit(map);
 	regmap_range_exit(map);
-	if (map->bus->free_context)
+	if (map->bus && map->bus->free_context)
 		map->bus->free_context(map->bus_context);
 	kfree(map->work_buf);
 	kfree(map);
@@ -916,6 +930,8 @@ static int _regmap_raw_write(struct regmap *map, unsigned int reg,
 	size_t len;
 	int i;
 
+	BUG_ON(!map->bus);
+
 	/* Check for unwritable registers before we start */
 	if (map->writeable_reg)
 		for (i = 0; i < val_len / map->format.val_bytes; i++)
@@ -1068,7 +1084,7 @@ static int _regmap_bus_formatted_write(void *context, unsigned int reg,
 	struct regmap_range_node *range;
 	struct regmap *map = context;
 
-	BUG_ON(!map->format.format_write);
+	BUG_ON(!map->bus || !map->format.format_write);
 
 	range = _regmap_range_lookup(map, reg);
 	if (range) {
@@ -1094,7 +1110,7 @@ static int _regmap_bus_raw_write(void *context, unsigned int reg,
 {
 	struct regmap *map = context;
 
-	BUG_ON(!map->format.format_val);
+	BUG_ON(!map->bus || !map->format.format_val);
 
 	map->format.format_val(map->work_buf + map->format.reg_bytes
 			       + map->format.pad_bytes, val, 0);
@@ -1105,12 +1121,18 @@ static int _regmap_bus_raw_write(void *context, unsigned int reg,
 				 map->format.val_bytes, false);
 }
 
+static inline void *_regmap_map_get_context(struct regmap *map)
+{
+	return (map->bus) ? map : map->bus_context;
+}
+
 int _regmap_write(struct regmap *map, unsigned int reg,
 		  unsigned int val)
 {
 	int ret;
+	void *context = _regmap_map_get_context(map);
 
-	if (!map->cache_bypass && map->format.format_write) {
+	if (!map->cache_bypass && !map->defer_caching) {
 		ret = regcache_write(map, reg, val);
 		if (ret != 0)
 			return ret;
@@ -1127,7 +1149,7 @@ int _regmap_write(struct regmap *map, unsigned int reg,
 
 	trace_regmap_reg_write(map->dev, reg, val);
 
-	return map->reg_write(map, reg, val);
+	return map->reg_write(context, reg, val);
 }
 
 /**
@@ -1178,6 +1200,8 @@ int regmap_raw_write(struct regmap *map, unsigned int reg,
 {
 	int ret;
 
+	if (!map->bus)
+		return -EINVAL;
 	if (val_len % map->format.val_bytes)
 		return -EINVAL;
 	if (reg % map->reg_stride)
@@ -1214,6 +1238,8 @@ int regmap_bulk_write(struct regmap *map, unsigned int reg, const void *val,
 	size_t val_bytes = map->format.val_bytes;
 	void *wval;
 
+	if (!map->bus)
+		return -EINVAL;
 	if (!map->format.parse_val)
 		return -EINVAL;
 	if (reg % map->reg_stride)
@@ -1310,6 +1336,8 @@ static int _regmap_raw_read(struct regmap *map, unsigned int reg, void *val,
 	u8 *u8 = map->work_buf;
 	int ret;
 
+	BUG_ON(!map->bus);
+
 	range = _regmap_range_lookup(map, reg);
 	if (range) {
 		ret = _regmap_select_page(map, &reg, range,
@@ -1361,6 +1389,8 @@ static int _regmap_read(struct regmap *map, unsigned int reg,
 			unsigned int *val)
 {
 	int ret;
+	void *context = _regmap_map_get_context(map);
+
 	BUG_ON(!map->reg_read);
 
 	if (!map->cache_bypass) {
@@ -1372,7 +1402,7 @@ static int _regmap_read(struct regmap *map, unsigned int reg,
 	if (map->cache_only)
 		return -EBUSY;
 
-	ret = map->reg_read(map, reg, val);
+	ret = map->reg_read(context, reg, val);
 	if (ret == 0) {
 #ifdef LOG_DEVICE
 		if (strcmp(dev_name(map->dev), LOG_DEVICE) == 0)
@@ -1434,6 +1464,8 @@ int regmap_raw_read(struct regmap *map, unsigned int reg, void *val,
 	unsigned int v;
 	int ret, i;
 
+	if (!map->bus)
+		return -EINVAL;
 	if (val_len % map->format.val_bytes)
 		return -EINVAL;
 	if (reg % map->reg_stride)
@@ -1485,6 +1517,8 @@ int regmap_bulk_read(struct regmap *map, unsigned int reg, void *val,
 	size_t val_bytes = map->format.val_bytes;
 	bool vol = regmap_volatile_range(map, reg, val_count);
 
+	if (!map->bus)
+		return -EINVAL;
 	if (!map->format.parse_val)
 		return -EINVAL;
 	if (reg % map->reg_stride)
diff --git a/include/linux/regmap.h b/include/linux/regmap.h
index 017b3bd085a2..bf77dfdabef9 100644
--- a/include/linux/regmap.h
+++ b/include/linux/regmap.h
@@ -128,7 +128,18 @@ typedef void (*regmap_unlock)(void *);
  * @lock_arg:	  this field is passed as the only argument of lock/unlock
  *		  functions (ignored in case regular lock/unlock functions
  *		  are not overridden).
- *
+ * @reg_read:	  Optional callback that if filled will be used to perform
+ *           	  all the reads from the registers. Should only be provided for
+ *		  devices whos read operation cannot be represented as a simple read
+ *		  operation on a bus such as SPI, I2C, etc. Most of the devices do
+ * 		  not need this.
+ * @reg_write:	  Same as above for writing.
+ * @fast_io:	  Register IO is fast. Use a spinlock instead of a mutex
+ *	     	  to perform locking. This field is ignored if custom lock/unlock
+ *	     	  functions are used (see fields lock/unlock of struct regmap_config).
+ *		  This field is a duplicate of a similar file in
+ *		  'struct regmap_bus' and serves exact same purpose.
+ *		   Use it only for "no-bus" cases.
  * @max_register: Optional, specifies the maximum valid register index.
  * @wr_table:     Optional, points to a struct regmap_access_table specifying
  *                valid ranges for write access.
@@ -178,6 +189,11 @@ struct regmap_config {
 	regmap_unlock unlock;
 	void *lock_arg;
 
+	int (*reg_read)(void *context, unsigned int reg, unsigned int *val);
+	int (*reg_write)(void *context, unsigned int reg, unsigned int val);
+
+	bool fast_io;
+
 	unsigned int max_register;
 	const struct regmap_access_table *wr_table;
 	const struct regmap_access_table *rd_table;