diff --git a/drivers/base/regmap/internal.h b/drivers/base/regmap/internal.h
index 5308e3e870ba..57f777835d97 100644
--- a/drivers/base/regmap/internal.h
+++ b/drivers/base/regmap/internal.h
@@ -128,9 +128,6 @@ struct regmap {
 	void *cache;
 	u32 cache_dirty;
 
-	unsigned long *cache_present;
-	unsigned int cache_present_nbits;
-
 	struct reg_default *patch;
 	int patch_regs;
 
@@ -203,6 +200,7 @@ int regcache_write(struct regmap *map,
 			unsigned int reg, unsigned int value);
 int regcache_sync(struct regmap *map);
 int regcache_sync_block(struct regmap *map, void *block,
+			unsigned long *cache_present,
 			unsigned int block_base, unsigned int start,
 			unsigned int end);
 
@@ -218,16 +216,6 @@ unsigned int regcache_get_val(struct regmap *map, const void *base,
 bool regcache_set_val(struct regmap *map, void *base, unsigned int idx,
 		      unsigned int val);
 int regcache_lookup_reg(struct regmap *map, unsigned int reg);
-int regcache_set_reg_present(struct regmap *map, unsigned int reg);
-
-static inline bool regcache_reg_present(struct regmap *map, unsigned int reg)
-{
-	if (!map->cache_present)
-		return false;
-	if (reg > map->cache_present_nbits)
-		return false;
-	return map->cache_present[BIT_WORD(reg)] & BIT_MASK(reg);
-}
 
 int _regmap_raw_write(struct regmap *map, unsigned int reg,
 		      const void *val, size_t val_len, bool async);
diff --git a/drivers/base/regmap/regcache-rbtree.c b/drivers/base/regmap/regcache-rbtree.c
index 5c1435c4e210..e9a2261a383b 100644
--- a/drivers/base/regmap/regcache-rbtree.c
+++ b/drivers/base/regmap/regcache-rbtree.c
@@ -29,6 +29,8 @@ struct regcache_rbtree_node {
 	unsigned int base_reg;
 	/* block of adjacent registers */
 	void *block;
+	/* Which registers are present */
+	long *cache_present;
 	/* number of registers available in the block */
 	unsigned int blklen;
 } __attribute__ ((packed));
@@ -57,6 +59,7 @@ static void regcache_rbtree_set_register(struct regmap *map,
 					 struct regcache_rbtree_node *rbnode,
 					 unsigned int idx, unsigned int val)
 {
+	set_bit(idx, rbnode->cache_present);
 	regcache_set_val(map, rbnode->block, idx, val);
 }
 
@@ -146,13 +149,13 @@ static int rbtree_show(struct seq_file *s, void *ignored)
 	map->lock(map->lock_arg);
 
 	mem_size = sizeof(*rbtree_ctx);
-	mem_size += BITS_TO_LONGS(map->cache_present_nbits) * sizeof(long);
 
 	for (node = rb_first(&rbtree_ctx->root); node != NULL;
 	     node = rb_next(node)) {
 		n = container_of(node, struct regcache_rbtree_node, node);
 		mem_size += sizeof(*n);
 		mem_size += (n->blklen * map->cache_word_size);
+		mem_size += BITS_TO_LONGS(n->blklen) * sizeof(long);
 
 		regcache_rbtree_get_base_top_reg(map, n, &base, &top);
 		this_registers = ((top - base) / map->reg_stride) + 1;
@@ -245,6 +248,7 @@ static int regcache_rbtree_exit(struct regmap *map)
 		rbtree_node = rb_entry(next, struct regcache_rbtree_node, node);
 		next = rb_next(&rbtree_node->node);
 		rb_erase(&rbtree_node->node, &rbtree_ctx->root);
+		kfree(rbtree_node->cache_present);
 		kfree(rbtree_node->block);
 		kfree(rbtree_node);
 	}
@@ -265,7 +269,7 @@ static int regcache_rbtree_read(struct regmap *map,
 	rbnode = regcache_rbtree_lookup(map, reg);
 	if (rbnode) {
 		reg_tmp = (reg - rbnode->base_reg) / map->reg_stride;
-		if (!regcache_reg_present(map, reg))
+		if (!test_bit(reg_tmp, rbnode->cache_present))
 			return -ENOENT;
 		*value = regcache_rbtree_get_register(map, rbnode, reg_tmp);
 	} else {
@@ -278,27 +282,45 @@ static int regcache_rbtree_read(struct regmap *map,
 
 static int regcache_rbtree_insert_to_block(struct regmap *map,
 					   struct regcache_rbtree_node *rbnode,
-					   unsigned int pos, unsigned int reg,
+					   unsigned int base_reg,
+					   unsigned int top_reg,
+					   unsigned int reg,
 					   unsigned int value)
 {
+	unsigned int blklen;
+	unsigned int pos, offset;
+	unsigned long *present;
 	u8 *blk;
 
+	blklen = (top_reg - base_reg) / map->reg_stride + 1;
+	pos = (reg - base_reg) / map->reg_stride;
+	offset = (rbnode->base_reg - base_reg) / map->reg_stride;
+
 	blk = krealloc(rbnode->block,
-		       (rbnode->blklen + 1) * map->cache_word_size,
+		       blklen * map->cache_word_size,
 		       GFP_KERNEL);
 	if (!blk)
 		return -ENOMEM;
 
+	present = krealloc(rbnode->cache_present,
+		    BITS_TO_LONGS(blklen) * sizeof(*present), GFP_KERNEL);
+	if (!present) {
+		kfree(blk);
+		return -ENOMEM;
+	}
+
 	/* insert the register value in the correct place in the rbnode block */
-	memmove(blk + (pos + 1) * map->cache_word_size,
-		blk + pos * map->cache_word_size,
-		(rbnode->blklen - pos) * map->cache_word_size);
+	if (pos == 0) {
+		memmove(blk + offset * map->cache_word_size,
+			blk, rbnode->blklen * map->cache_word_size);
+		bitmap_shift_right(present, present, offset, blklen);
+	}
 
 	/* update the rbnode block, its size and the base register */
 	rbnode->block = blk;
-	rbnode->blklen++;
-	if (!pos)
-		rbnode->base_reg = reg;
+	rbnode->blklen = blklen;
+	rbnode->base_reg = base_reg;
+	rbnode->cache_present = present;
 
 	regcache_rbtree_set_register(map, rbnode, pos, value);
 	return 0;
@@ -325,8 +347,8 @@ regcache_rbtree_node_alloc(struct regmap *map, unsigned int reg)
 
 		if (i != map->rd_table->n_yes_ranges) {
 			range = &map->rd_table->yes_ranges[i];
-			rbnode->blklen = range->range_max - range->range_min
-				+ 1;
+			rbnode->blklen = (range->range_max - range->range_min) /
+				map->reg_stride	+ 1;
 			rbnode->base_reg = range->range_min;
 		}
 	}
@@ -338,12 +360,21 @@ regcache_rbtree_node_alloc(struct regmap *map, unsigned int reg)
 
 	rbnode->block = kmalloc(rbnode->blklen * map->cache_word_size,
 				GFP_KERNEL);
-	if (!rbnode->block) {
-		kfree(rbnode);
-		return NULL;
-	}
+	if (!rbnode->block)
+		goto err_free;
+
+	rbnode->cache_present = kzalloc(BITS_TO_LONGS(rbnode->blklen) *
+		sizeof(*rbnode->cache_present), GFP_KERNEL);
+	if (!rbnode->cache_present)
+		goto err_free_block;
 
 	return rbnode;
+
+err_free_block:
+	kfree(rbnode->block);
+err_free:
+	kfree(rbnode);
+	return NULL;
 }
 
 static int regcache_rbtree_write(struct regmap *map, unsigned int reg,
@@ -353,15 +384,9 @@ static int regcache_rbtree_write(struct regmap *map, unsigned int reg,
 	struct regcache_rbtree_node *rbnode, *rbnode_tmp;
 	struct rb_node *node;
 	unsigned int reg_tmp;
-	unsigned int pos;
-	int i;
 	int ret;
 
 	rbtree_ctx = map->cache;
-	/* update the reg_present bitmap, make space if necessary */
-	ret = regcache_set_reg_present(map, reg);
-	if (ret < 0)
-		return ret;
 
 	/* if we can't locate it in the cached rbnode we'll have
 	 * to traverse the rbtree looking for it.
@@ -371,30 +396,43 @@ static int regcache_rbtree_write(struct regmap *map, unsigned int reg,
 		reg_tmp = (reg - rbnode->base_reg) / map->reg_stride;
 		regcache_rbtree_set_register(map, rbnode, reg_tmp, value);
 	} else {
+		unsigned int base_reg, top_reg;
+		unsigned int new_base_reg, new_top_reg;
+		unsigned int min, max;
+		unsigned int max_dist;
+
+		max_dist = map->reg_stride * sizeof(*rbnode_tmp) /
+			map->cache_word_size;
+		if (reg < max_dist)
+			min = 0;
+		else
+			min = reg - max_dist;
+		max = reg + max_dist;
+
 		/* look for an adjacent register to the one we are about to add */
 		for (node = rb_first(&rbtree_ctx->root); node;
 		     node = rb_next(node)) {
 			rbnode_tmp = rb_entry(node, struct regcache_rbtree_node,
 					      node);
-			for (i = 0; i < rbnode_tmp->blklen; i++) {
-				reg_tmp = rbnode_tmp->base_reg +
-						(i * map->reg_stride);
-				if (abs(reg_tmp - reg) != map->reg_stride)
-					continue;
-				/* decide where in the block to place our register */
-				if (reg_tmp + map->reg_stride == reg)
-					pos = i + 1;
-				else
-					pos = i;
-				ret = regcache_rbtree_insert_to_block(map,
-								      rbnode_tmp,
-								      pos, reg,
-								      value);
-				if (ret)
-					return ret;
-				rbtree_ctx->cached_rbnode = rbnode_tmp;
-				return 0;
+
+			regcache_rbtree_get_base_top_reg(map, rbnode_tmp,
+				&base_reg, &top_reg);
+
+			if (base_reg <= max && top_reg >= min) {
+				new_base_reg = min(reg, base_reg);
+				new_top_reg = max(reg, top_reg);
+			} else {
+				continue;
 			}
+
+			ret = regcache_rbtree_insert_to_block(map, rbnode_tmp,
+							      new_base_reg,
+							      new_top_reg, reg,
+							      value);
+			if (ret)
+				return ret;
+			rbtree_ctx->cached_rbnode = rbnode_tmp;
+			return 0;
 		}
 
 		/* We did not manage to find a place to insert it in
@@ -418,30 +456,34 @@ static int regcache_rbtree_sync(struct regmap *map, unsigned int min,
 	struct regcache_rbtree_ctx *rbtree_ctx;
 	struct rb_node *node;
 	struct regcache_rbtree_node *rbnode;
+	unsigned int base_reg, top_reg;
+	unsigned int start, end;
 	int ret;
-	int base, end;
 
 	rbtree_ctx = map->cache;
 	for (node = rb_first(&rbtree_ctx->root); node; node = rb_next(node)) {
 		rbnode = rb_entry(node, struct regcache_rbtree_node, node);
 
-		if (rbnode->base_reg > max)
+		regcache_rbtree_get_base_top_reg(map, rbnode, &base_reg,
+			&top_reg);
+		if (base_reg > max)
 			break;
-		if (rbnode->base_reg + rbnode->blklen < min)
+		if (top_reg < min)
 			continue;
 
-		if (min > rbnode->base_reg)
-			base = min - rbnode->base_reg;
+		if (min > base_reg)
+			start = (min - base_reg) / map->reg_stride;
 		else
-			base = 0;
+			start = 0;
 
-		if (max < rbnode->base_reg + rbnode->blklen)
-			end = max - rbnode->base_reg + 1;
+		if (max < top_reg)
+			end = (max - base_reg) / map->reg_stride + 1;
 		else
 			end = rbnode->blklen;
 
-		ret = regcache_sync_block(map, rbnode->block, rbnode->base_reg,
-					  base, end);
+		ret = regcache_sync_block(map, rbnode->block,
+					  rbnode->cache_present,
+					  rbnode->base_reg, start, end);
 		if (ret != 0)
 			return ret;
 	}
@@ -449,6 +491,42 @@ static int regcache_rbtree_sync(struct regmap *map, unsigned int min,
 	return regmap_async_complete(map);
 }
 
+static int regcache_rbtree_drop(struct regmap *map, unsigned int min,
+				unsigned int max)
+{
+	struct regcache_rbtree_ctx *rbtree_ctx;
+	struct regcache_rbtree_node *rbnode;
+	struct rb_node *node;
+	unsigned int base_reg, top_reg;
+	unsigned int start, end;
+
+	rbtree_ctx = map->cache;
+	for (node = rb_first(&rbtree_ctx->root); node; node = rb_next(node)) {
+		rbnode = rb_entry(node, struct regcache_rbtree_node, node);
+
+		regcache_rbtree_get_base_top_reg(map, rbnode, &base_reg,
+			&top_reg);
+		if (base_reg > max)
+			break;
+		if (top_reg < min)
+			continue;
+
+		if (min > base_reg)
+			start = (min - base_reg) / map->reg_stride;
+		else
+			start = 0;
+
+		if (max < top_reg)
+			end = (max - base_reg) / map->reg_stride + 1;
+		else
+			end = rbnode->blklen;
+
+		bitmap_clear(rbnode->cache_present, start, end - start);
+	}
+
+	return 0;
+}
+
 struct regcache_ops regcache_rbtree_ops = {
 	.type = REGCACHE_RBTREE,
 	.name = "rbtree",
@@ -456,5 +534,6 @@ struct regcache_ops regcache_rbtree_ops = {
 	.exit = regcache_rbtree_exit,
 	.read = regcache_rbtree_read,
 	.write = regcache_rbtree_write,
-	.sync = regcache_rbtree_sync
+	.sync = regcache_rbtree_sync,
+	.drop = regcache_rbtree_drop,
 };
diff --git a/drivers/base/regmap/regcache.c b/drivers/base/regmap/regcache.c
index e2abd0548e7b..d6c2d691b6e8 100644
--- a/drivers/base/regmap/regcache.c
+++ b/drivers/base/regmap/regcache.c
@@ -121,8 +121,6 @@ int regcache_init(struct regmap *map, const struct regmap_config *config)
 	map->reg_defaults_raw = config->reg_defaults_raw;
 	map->cache_word_size = DIV_ROUND_UP(config->val_bits, 8);
 	map->cache_size_raw = map->cache_word_size * config->num_reg_defaults_raw;
-	map->cache_present = NULL;
-	map->cache_present_nbits = 0;
 
 	map->cache = NULL;
 	map->cache_ops = cache_types[i];
@@ -181,7 +179,6 @@ void regcache_exit(struct regmap *map)
 
 	BUG_ON(!map->cache_ops);
 
-	kfree(map->cache_present);
 	kfree(map->reg_defaults);
 	if (map->cache_free)
 		kfree(map->reg_defaults_raw);
@@ -407,22 +404,16 @@ EXPORT_SYMBOL_GPL(regcache_sync_region);
 int regcache_drop_region(struct regmap *map, unsigned int min,
 			 unsigned int max)
 {
-	unsigned int reg;
 	int ret = 0;
 
-	if (!map->cache_present && !(map->cache_ops && map->cache_ops->drop))
+	if (!map->cache_ops || !map->cache_ops->drop)
 		return -EINVAL;
 
 	map->lock(map->lock_arg);
 
 	trace_regcache_drop_region(map->dev, min, max);
 
-	if (map->cache_present)
-		for (reg = min; reg < max + 1; reg++)
-			clear_bit(reg, map->cache_present);
-
-	if (map->cache_ops && map->cache_ops->drop)
-		ret = map->cache_ops->drop(map, min, max);
+	ret = map->cache_ops->drop(map, min, max);
 
 	map->unlock(map->lock_arg);
 
@@ -490,42 +481,6 @@ void regcache_cache_bypass(struct regmap *map, bool enable)
 }
 EXPORT_SYMBOL_GPL(regcache_cache_bypass);
 
-int regcache_set_reg_present(struct regmap *map, unsigned int reg)
-{
-	unsigned long *cache_present;
-	unsigned int cache_present_size;
-	unsigned int nregs;
-	int i;
-
-	nregs = reg + 1;
-	cache_present_size = BITS_TO_LONGS(nregs);
-	cache_present_size *= sizeof(long);
-
-	if (!map->cache_present) {
-		cache_present = kmalloc(cache_present_size, GFP_KERNEL);
-		if (!cache_present)
-			return -ENOMEM;
-		bitmap_zero(cache_present, nregs);
-		map->cache_present = cache_present;
-		map->cache_present_nbits = nregs;
-	}
-
-	if (nregs > map->cache_present_nbits) {
-		cache_present = krealloc(map->cache_present,
-					 cache_present_size, GFP_KERNEL);
-		if (!cache_present)
-			return -ENOMEM;
-		for (i = 0; i < nregs; i++)
-			if (i >= map->cache_present_nbits)
-				clear_bit(i, cache_present);
-		map->cache_present = cache_present;
-		map->cache_present_nbits = nregs;
-	}
-
-	set_bit(reg, map->cache_present);
-	return 0;
-}
-
 bool regcache_set_val(struct regmap *map, void *base, unsigned int idx,
 		      unsigned int val)
 {
@@ -617,7 +572,16 @@ int regcache_lookup_reg(struct regmap *map, unsigned int reg)
 		return -ENOENT;
 }
 
+static bool regcache_reg_present(unsigned long *cache_present, unsigned int idx)
+{
+	if (!cache_present)
+		return true;
+
+	return test_bit(idx, cache_present);
+}
+
 static int regcache_sync_block_single(struct regmap *map, void *block,
+				      unsigned long *cache_present,
 				      unsigned int block_base,
 				      unsigned int start, unsigned int end)
 {
@@ -627,7 +591,7 @@ static int regcache_sync_block_single(struct regmap *map, void *block,
 	for (i = start; i < end; i++) {
 		regtmp = block_base + (i * map->reg_stride);
 
-		if (!regcache_reg_present(map, regtmp))
+		if (!regcache_reg_present(cache_present, i))
 			continue;
 
 		val = regcache_get_val(map, block, i);
@@ -678,6 +642,7 @@ static int regcache_sync_block_raw_flush(struct regmap *map, const void **data,
 }
 
 static int regcache_sync_block_raw(struct regmap *map, void *block,
+			    unsigned long *cache_present,
 			    unsigned int block_base, unsigned int start,
 			    unsigned int end)
 {
@@ -690,7 +655,7 @@ static int regcache_sync_block_raw(struct regmap *map, void *block,
 	for (i = start; i < end; i++) {
 		regtmp = block_base + (i * map->reg_stride);
 
-		if (!regcache_reg_present(map, regtmp)) {
+		if (!regcache_reg_present(cache_present, i)) {
 			ret = regcache_sync_block_raw_flush(map, &data,
 							    base, regtmp);
 			if (ret != 0)
@@ -721,13 +686,14 @@ static int regcache_sync_block_raw(struct regmap *map, void *block,
 }
 
 int regcache_sync_block(struct regmap *map, void *block,
+			unsigned long *cache_present,
 			unsigned int block_base, unsigned int start,
 			unsigned int end)
 {
 	if (regmap_can_raw_write(map))
-		return regcache_sync_block_raw(map, block, block_base,
-					       start, end);
+		return regcache_sync_block_raw(map, block, cache_present,
+					       block_base, start, end);
 	else
-		return regcache_sync_block_single(map, block, block_base,
-						  start, end);
+		return regcache_sync_block_single(map, block, cache_present,
+						  block_base, start, end);
 }