diff --git a/drivers/base/regmap/regcache-rbtree.c b/drivers/base/regmap/regcache-rbtree.c
index ae6b8788d5f3..d65715b9e129 100644
--- a/drivers/base/regmap/regcache-rbtree.c
+++ b/drivers/base/regmap/regcache-rbtree.c
@@ -453,7 +453,8 @@ static int regcache_rbtree_write(struct regmap *map, unsigned int reg,
 		if (!rbnode)
 			return -ENOMEM;
 		regcache_rbtree_set_register(map, rbnode,
-					     reg - rbnode->base_reg, value);
+					     (reg - rbnode->base_reg) / map->reg_stride,
+					     value);
 		regcache_rbtree_insert(map, &rbtree_ctx->root, rbnode);
 		rbtree_ctx->cached_rbnode = rbnode;
 	}