Merge branch 'for-linus' of git://opensource.wolfsonmicro.com/regmap

* 'for-linus' of git://opensource.wolfsonmicro.com/regmap: (62 commits)
  mfd: Enable rbtree cache for wm831x devices
  regmap: Support some block operations on cached devices
  regmap: Allow caches for devices with no defaults
  regmap: Ensure rbtree syncs registers set to zero properly
  regmap: Allow rbtree to cache zero default values
  regmap: Warn on raw I/O as well as bulk reads that bypass cache
  regmap: Return a sensible error code if we fail to read the cache
  regmap: Use bsearch() to search the register defaults
  regmap: Fix doc comment
  regmap: Optimize the lookup path to use binary search
  regmap: Ensure we scream if we enable cache bypass/only at the same time
  regmap: Implement regcache_cache_bypass helper function
  regmap: Save/restore the bypass state upon syncing
  regmap: Lock the sync path, ensure we use the lockless _regmap_write()
  regmap: Fix apostrophe usage
  regmap: Make _regmap_write() global
  regmap: Fix lock used for regcache_cache_only()
  regmap: Grab the lock in regcache_cache_only()
  regmap: Modify map->cache_bypass directly
  regmap: Fix regcache_sync generic implementation
  ...

23 files changed, 2421 insertions, 567 deletions

diff --git a/drivers/base/regmap/Kconfig b/drivers/base/regmap/Kconfig
index fabbf6cc5367..2fc6a66f39a4 100644
--- a/drivers/base/regmap/Kconfig
+++ b/drivers/base/regmap/Kconfig
@@ -4,6 +4,8 @@
 
 config REGMAP
 	default y if (REGMAP_I2C || REGMAP_SPI)
+	select LZO_COMPRESS
+	select LZO_DECOMPRESS
 	bool
 
 config REGMAP_I2C
diff --git a/drivers/base/regmap/Makefile b/drivers/base/regmap/Makefile
index f476f4571295..0573c8a9dacb 100644
--- a/drivers/base/regmap/Makefile
+++ b/drivers/base/regmap/Makefile
@@ -1,3 +1,4 @@
-obj-$(CONFIG_REGMAP) += regmap.o
+obj-$(CONFIG_REGMAP) += regmap.o regcache.o regcache-indexed.o regcache-rbtree.o regcache-lzo.o
+obj-$(CONFIG_DEBUG_FS) += regmap-debugfs.o
 obj-$(CONFIG_REGMAP_I2C) += regmap-i2c.o
 obj-$(CONFIG_REGMAP_SPI) += regmap-spi.o
diff --git a/drivers/base/regmap/internal.h b/drivers/base/regmap/internal.h
new file mode 100644
index 000000000000..348ff02eb93e
--- /dev/null
+++ b/drivers/base/regmap/internal.h
@@ -0,0 +1,128 @@
+/*
+ * Register map access API internal header
+ *
+ * Copyright 2011 Wolfson Microelectronics plc
+ *
+ * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef _REGMAP_INTERNAL_H
+#define _REGMAP_INTERNAL_H
+
+#include <linux/regmap.h>
+#include <linux/fs.h>
+
+struct regmap;
+struct regcache_ops;
+
+struct regmap_format {
+	size_t buf_size;
+	size_t reg_bytes;
+	size_t val_bytes;
+	void (*format_write)(struct regmap *map,
+			     unsigned int reg, unsigned int val);
+	void (*format_reg)(void *buf, unsigned int reg);
+	void (*format_val)(void *buf, unsigned int val);
+	unsigned int (*parse_val)(void *buf);
+};
+
+struct regmap {
+	struct mutex lock;
+
+	struct device *dev; /* Device we do I/O on */
+	void *work_buf;     /* Scratch buffer used to format I/O */
+	struct regmap_format format;  /* Buffer format */
+	const struct regmap_bus *bus;
+
+#ifdef CONFIG_DEBUG_FS
+	struct dentry *debugfs;
+#endif
+
+	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);
+
+	u8 read_flag_mask;
+	u8 write_flag_mask;
+
+	/* regcache specific members */
+	const struct regcache_ops *cache_ops;
+	enum regcache_type cache_type;
+
+	/* number of bytes in reg_defaults_raw */
+	unsigned int cache_size_raw;
+	/* number of bytes per word in reg_defaults_raw */
+	unsigned int cache_word_size;
+	/* number of entries in reg_defaults */
+	unsigned int num_reg_defaults;
+	/* number of entries in reg_defaults_raw */
+	unsigned int num_reg_defaults_raw;
+
+	/* if set, only the cache is modified not the HW */
+	unsigned int cache_only:1;
+	/* if set, only the HW is modified not the cache */
+	unsigned int cache_bypass:1;
+	/* if set, remember to free reg_defaults_raw */
+	unsigned int cache_free:1;
+
+	struct reg_default *reg_defaults;
+	const void *reg_defaults_raw;
+	void *cache;
+};
+
+struct regcache_ops {
+	const char *name;
+	enum regcache_type type;
+	int (*init)(struct regmap *map);
+	int (*exit)(struct regmap *map);
+	int (*read)(struct regmap *map, unsigned int reg, unsigned int *value);
+	int (*write)(struct regmap *map, unsigned int reg, unsigned int value);
+	int (*sync)(struct regmap *map);
+};
+
+bool regmap_writeable(struct regmap *map, unsigned int reg);
+bool regmap_readable(struct regmap *map, unsigned int reg);
+bool regmap_volatile(struct regmap *map, unsigned int reg);
+bool regmap_precious(struct regmap *map, unsigned int reg);
+
+int _regmap_write(struct regmap *map, unsigned int reg,
+		  unsigned int val);
+
+#ifdef CONFIG_DEBUG_FS
+extern void regmap_debugfs_initcall(void);
+extern void regmap_debugfs_init(struct regmap *map);
+extern void regmap_debugfs_exit(struct regmap *map);
+#else
+static inline void regmap_debugfs_initcall(void) { }
+static inline void regmap_debugfs_init(struct regmap *map) { }
+static inline void regmap_debugfs_exit(struct regmap *map) { }
+#endif
+
+/* regcache core declarations */
+int regcache_init(struct regmap *map);
+void regcache_exit(struct regmap *map);
+int regcache_read(struct regmap *map,
+		       unsigned int reg, unsigned int *value);
+int regcache_write(struct regmap *map,
+			unsigned int reg, unsigned int value);
+int regcache_sync(struct regmap *map);
+
+unsigned int regcache_get_val(const void *base, unsigned int idx,
+			      unsigned int word_size);
+bool regcache_set_val(void *base, unsigned int idx,
+		      unsigned int val, unsigned int word_size);
+int regcache_lookup_reg(struct regmap *map, unsigned int reg);
+int regcache_insert_reg(struct regmap *map, unsigned int reg,
+			unsigned int val);
+
+extern struct regcache_ops regcache_indexed_ops;
+extern struct regcache_ops regcache_rbtree_ops;
+extern struct regcache_ops regcache_lzo_ops;
+
+#endif
diff --git a/drivers/base/regmap/regcache-indexed.c b/drivers/base/regmap/regcache-indexed.c
new file mode 100644
index 000000000000..507731ad8ec1
--- /dev/null
+++ b/drivers/base/regmap/regcache-indexed.c
@@ -0,0 +1,64 @@
+/*
+ * Register cache access API - indexed caching support
+ *
+ * Copyright 2011 Wolfson Microelectronics plc
+ *
+ * Author: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/slab.h>
+
+#include "internal.h"
+
+static int regcache_indexed_read(struct regmap *map, unsigned int reg,
+				 unsigned int *value)
+{
+	int ret;
+
+	ret = regcache_lookup_reg(map, reg);
+	if (ret >= 0)
+		*value = map->reg_defaults[ret].def;
+
+	return ret;
+}
+
+static int regcache_indexed_write(struct regmap *map, unsigned int reg,
+				  unsigned int value)
+{
+	int ret;
+
+	ret = regcache_lookup_reg(map, reg);
+	if (ret < 0)
+		return regcache_insert_reg(map, reg, value);
+	map->reg_defaults[ret].def = value;
+	return 0;
+}
+
+static int regcache_indexed_sync(struct regmap *map)
+{
+	unsigned int i;
+	int ret;
+
+	for (i = 0; i < map->num_reg_defaults; i++) {
+		ret = _regmap_write(map, map->reg_defaults[i].reg,
+				    map->reg_defaults[i].def);
+		if (ret < 0)
+			return ret;
+		dev_dbg(map->dev, "Synced register %#x, value %#x\n",
+			map->reg_defaults[i].reg,
+			map->reg_defaults[i].def);
+	}
+	return 0;
+}
+
+struct regcache_ops regcache_indexed_ops = {
+	.type = REGCACHE_INDEXED,
+	.name = "indexed",
+	.read = regcache_indexed_read,
+	.write = regcache_indexed_write,
+	.sync = regcache_indexed_sync
+};
diff --git a/drivers/base/regmap/regcache-lzo.c b/drivers/base/regmap/regcache-lzo.c
new file mode 100644
index 000000000000..066aeece3626
--- /dev/null
+++ b/drivers/base/regmap/regcache-lzo.c
@@ -0,0 +1,361 @@
+/*
+ * Register cache access API - LZO caching support
+ *
+ * Copyright 2011 Wolfson Microelectronics plc
+ *
+ * Author: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/slab.h>
+#include <linux/lzo.h>
+
+#include "internal.h"
+
+struct regcache_lzo_ctx {
+	void *wmem;
+	void *dst;
+	const void *src;
+	size_t src_len;
+	size_t dst_len;
+	size_t decompressed_size;
+	unsigned long *sync_bmp;
+	int sync_bmp_nbits;
+};
+
+#define LZO_BLOCK_NUM 8
+static int regcache_lzo_block_count(void)
+{
+	return LZO_BLOCK_NUM;
+}
+
+static int regcache_lzo_prepare(struct regcache_lzo_ctx *lzo_ctx)
+{
+	lzo_ctx->wmem = kmalloc(LZO1X_MEM_COMPRESS, GFP_KERNEL);
+	if (!lzo_ctx->wmem)
+		return -ENOMEM;
+	return 0;
+}
+
+static int regcache_lzo_compress(struct regcache_lzo_ctx *lzo_ctx)
+{
+	size_t compress_size;
+	int ret;
+
+	ret = lzo1x_1_compress(lzo_ctx->src, lzo_ctx->src_len,
+			       lzo_ctx->dst, &compress_size, lzo_ctx->wmem);
+	if (ret != LZO_E_OK || compress_size > lzo_ctx->dst_len)
+		return -EINVAL;
+	lzo_ctx->dst_len = compress_size;
+	return 0;
+}
+
+static int regcache_lzo_decompress(struct regcache_lzo_ctx *lzo_ctx)
+{
+	size_t dst_len;
+	int ret;
+
+	dst_len = lzo_ctx->dst_len;
+	ret = lzo1x_decompress_safe(lzo_ctx->src, lzo_ctx->src_len,
+				    lzo_ctx->dst, &dst_len);
+	if (ret != LZO_E_OK || dst_len != lzo_ctx->dst_len)
+		return -EINVAL;
+	return 0;
+}
+
+static int regcache_lzo_compress_cache_block(struct regmap *map,
+		struct regcache_lzo_ctx *lzo_ctx)
+{
+	int ret;
+
+	lzo_ctx->dst_len = lzo1x_worst_compress(PAGE_SIZE);
+	lzo_ctx->dst = kmalloc(lzo_ctx->dst_len, GFP_KERNEL);
+	if (!lzo_ctx->dst) {
+		lzo_ctx->dst_len = 0;
+		return -ENOMEM;
+	}
+
+	ret = regcache_lzo_compress(lzo_ctx);
+	if (ret < 0)
+		return ret;
+	return 0;
+}
+
+static int regcache_lzo_decompress_cache_block(struct regmap *map,
+		struct regcache_lzo_ctx *lzo_ctx)
+{
+	int ret;
+
+	lzo_ctx->dst_len = lzo_ctx->decompressed_size;
+	lzo_ctx->dst = kmalloc(lzo_ctx->dst_len, GFP_KERNEL);
+	if (!lzo_ctx->dst) {
+		lzo_ctx->dst_len = 0;
+		return -ENOMEM;
+	}
+
+	ret = regcache_lzo_decompress(lzo_ctx);
+	if (ret < 0)
+		return ret;
+	return 0;
+}
+
+static inline int regcache_lzo_get_blkindex(struct regmap *map,
+					    unsigned int reg)
+{
+	return (reg * map->cache_word_size) /
+		DIV_ROUND_UP(map->cache_size_raw, regcache_lzo_block_count());
+}
+
+static inline int regcache_lzo_get_blkpos(struct regmap *map,
+					  unsigned int reg)
+{
+	return reg % (DIV_ROUND_UP(map->cache_size_raw, regcache_lzo_block_count()) /
+		      map->cache_word_size);
+}
+
+static inline int regcache_lzo_get_blksize(struct regmap *map)
+{
+	return DIV_ROUND_UP(map->cache_size_raw, regcache_lzo_block_count());
+}
+
+static int regcache_lzo_init(struct regmap *map)
+{
+	struct regcache_lzo_ctx **lzo_blocks;
+	size_t bmp_size;
+	int ret, i, blksize, blkcount;
+	const char *p, *end;
+	unsigned long *sync_bmp;
+
+	ret = 0;
+
+	blkcount = regcache_lzo_block_count();
+	map->cache = kzalloc(blkcount * sizeof *lzo_blocks,
+			     GFP_KERNEL);
+	if (!map->cache)
+		return -ENOMEM;
+	lzo_blocks = map->cache;
+
+	/*
+	 * allocate a bitmap to be used when syncing the cache with
+	 * the hardware.  Each time a register is modified, the corresponding
+	 * bit is set in the bitmap, so we know that we have to sync
+	 * that register.
+	 */
+	bmp_size = map->num_reg_defaults_raw;
+	sync_bmp = kmalloc(BITS_TO_LONGS(bmp_size) * sizeof(long),
+			   GFP_KERNEL);
+	if (!sync_bmp) {
+		ret = -ENOMEM;
+		goto err;
+	}
+	bitmap_zero(sync_bmp, bmp_size);
+
+	/* allocate the lzo blocks and initialize them */
+	for (i = 0; i < blkcount; i++) {
+		lzo_blocks[i] = kzalloc(sizeof **lzo_blocks,
+					GFP_KERNEL);
+		if (!lzo_blocks[i]) {
+			kfree(sync_bmp);
+			ret = -ENOMEM;
+			goto err;
+		}
+		lzo_blocks[i]->sync_bmp = sync_bmp;
+		lzo_blocks[i]->sync_bmp_nbits = bmp_size;
+		/* alloc the working space for the compressed block */
+		ret = regcache_lzo_prepare(lzo_blocks[i]);
+		if (ret < 0)
+			goto err;
+	}
+
+	blksize = regcache_lzo_get_blksize(map);
+	p = map->reg_defaults_raw;
+	end = map->reg_defaults_raw + map->cache_size_raw;
+	/* compress the register map and fill the lzo blocks */
+	for (i = 0; i < blkcount; i++, p += blksize) {
+		lzo_blocks[i]->src = p;
+		if (p + blksize > end)
+			lzo_blocks[i]->src_len = end - p;
+		else
+			lzo_blocks[i]->src_len = blksize;
+		ret = regcache_lzo_compress_cache_block(map,
+						       lzo_blocks[i]);
+		if (ret < 0)
+			goto err;
+		lzo_blocks[i]->decompressed_size =
+			lzo_blocks[i]->src_len;
+	}
+
+	return 0;
+err:
+	regcache_exit(map);
+	return ret;
+}
+
+static int regcache_lzo_exit(struct regmap *map)
+{
+	struct regcache_lzo_ctx **lzo_blocks;
+	int i, blkcount;
+
+	lzo_blocks = map->cache;
+	if (!lzo_blocks)
+		return 0;
+
+	blkcount = regcache_lzo_block_count();
+	/*
+	 * the pointer to the bitmap used for syncing the cache
+	 * is shared amongst all lzo_blocks.  Ensure it is freed
+	 * only once.
+	 */
+	if (lzo_blocks[0])
+		kfree(lzo_blocks[0]->sync_bmp);
+	for (i = 0; i < blkcount; i++) {
+		if (lzo_blocks[i]) {
+			kfree(lzo_blocks[i]->wmem);
+			kfree(lzo_blocks[i]->dst);
+		}
+		/* each lzo_block is a pointer returned by kmalloc or NULL */
+		kfree(lzo_blocks[i]);
+	}
+	kfree(lzo_blocks);
+	map->cache = NULL;
+	return 0;
+}
+
+static int regcache_lzo_read(struct regmap *map,
+			     unsigned int reg, unsigned int *value)
+{
+	struct regcache_lzo_ctx *lzo_block, **lzo_blocks;
+	int ret, blkindex, blkpos;
+	size_t blksize, tmp_dst_len;
+	void *tmp_dst;
+
+	/* index of the compressed lzo block */
+	blkindex = regcache_lzo_get_blkindex(map, reg);
+	/* register index within the decompressed block */
+	blkpos = regcache_lzo_get_blkpos(map, reg);
+	/* size of the compressed block */
+	blksize = regcache_lzo_get_blksize(map);
+	lzo_blocks = map->cache;
+	lzo_block = lzo_blocks[blkindex];
+
+	/* save the pointer and length of the compressed block */
+	tmp_dst = lzo_block->dst;
+	tmp_dst_len = lzo_block->dst_len;
+
+	/* prepare the source to be the compressed block */
+	lzo_block->src = lzo_block->dst;
+	lzo_block->src_len = lzo_block->dst_len;
+
+	/* decompress the block */
+	ret = regcache_lzo_decompress_cache_block(map, lzo_block);
+	if (ret >= 0)
+		/* fetch the value from the cache */
+		*value = regcache_get_val(lzo_block->dst, blkpos,
+					  map->cache_word_size);
+
+	kfree(lzo_block->dst);
+	/* restore the pointer and length of the compressed block */
+	lzo_block->dst = tmp_dst;
+	lzo_block->dst_len = tmp_dst_len;
+
+	return ret;
+}
+
+static int regcache_lzo_write(struct regmap *map,
+			      unsigned int reg, unsigned int value)
+{
+	struct regcache_lzo_ctx *lzo_block, **lzo_blocks;
+	int ret, blkindex, blkpos;
+	size_t blksize, tmp_dst_len;
+	void *tmp_dst;
+
+	/* index of the compressed lzo block */
+	blkindex = regcache_lzo_get_blkindex(map, reg);
+	/* register index within the decompressed block */
+	blkpos = regcache_lzo_get_blkpos(map, reg);
+	/* size of the compressed block */
+	blksize = regcache_lzo_get_blksize(map);
+	lzo_blocks = map->cache;
+	lzo_block = lzo_blocks[blkindex];
+
+	/* save the pointer and length of the compressed block */
+	tmp_dst = lzo_block->dst;
+	tmp_dst_len = lzo_block->dst_len;
+
+	/* prepare the source to be the compressed block */
+	lzo_block->src = lzo_block->dst;
+	lzo_block->src_len = lzo_block->dst_len;
+
+	/* decompress the block */
+	ret = regcache_lzo_decompress_cache_block(map, lzo_block);
+	if (ret < 0) {
+		kfree(lzo_block->dst);
+		goto out;
+	}
+
+	/* write the new value to the cache */
+	if (regcache_set_val(lzo_block->dst, blkpos, value,
+			     map->cache_word_size)) {
+		kfree(lzo_block->dst);
+		goto out;
+	}
+
+	/* prepare the source to be the decompressed block */
+	lzo_block->src = lzo_block->dst;
+	lzo_block->src_len = lzo_block->dst_len;
+
+	/* compress the block */
+	ret = regcache_lzo_compress_cache_block(map, lzo_block);
+	if (ret < 0) {
+		kfree(lzo_block->dst);
+		kfree(lzo_block->src);
+		goto out;
+	}
+
+	/* set the bit so we know we have to sync this register */
+	set_bit(reg, lzo_block->sync_bmp);
+	kfree(tmp_dst);
+	kfree(lzo_block->src);
+	return 0;
+out:
+	lzo_block->dst = tmp_dst;
+	lzo_block->dst_len = tmp_dst_len;
+	return ret;
+}
+
+static int regcache_lzo_sync(struct regmap *map)
+{
+	struct regcache_lzo_ctx **lzo_blocks;
+	unsigned int val;
+	int i;
+	int ret;
+
+	lzo_blocks = map->cache;
+	for_each_set_bit(i, lzo_blocks[0]->sync_bmp, lzo_blocks[0]->sync_bmp_nbits) {
+		ret = regcache_read(map, i, &val);
+		if (ret)
+			return ret;
+		map->cache_bypass = 1;
+		ret = _regmap_write(map, i, val);
+		map->cache_bypass = 0;
+		if (ret)
+			return ret;
+		dev_dbg(map->dev, "Synced register %#x, value %#x\n",
+			i, val);
+	}
+
+	return 0;
+}
+
+struct regcache_ops regcache_lzo_ops = {
+	.type = REGCACHE_LZO,
+	.name = "lzo",
+	.init = regcache_lzo_init,
+	.exit = regcache_lzo_exit,
+	.read = regcache_lzo_read,
+	.write = regcache_lzo_write,
+	.sync = regcache_lzo_sync
+};
diff --git a/drivers/base/regmap/regcache-rbtree.c b/drivers/base/regmap/regcache-rbtree.c
new file mode 100644
index 000000000000..e31498499b0f
--- /dev/null
+++ b/drivers/base/regmap/regcache-rbtree.c
@@ -0,0 +1,345 @@
+/*
+ * Register cache access API - rbtree caching support
+ *
+ * Copyright 2011 Wolfson Microelectronics plc
+ *
+ * Author: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/slab.h>
+#include <linux/rbtree.h>
+
+#include "internal.h"
+
+static int regcache_rbtree_write(struct regmap *map, unsigned int reg,
+				 unsigned int value);
+
+struct regcache_rbtree_node {
+	/* the actual rbtree node holding this block */
+	struct rb_node node;
+	/* base register handled by this block */
+	unsigned int base_reg;
+	/* block of adjacent registers */
+	void *block;
+	/* number of registers available in the block */
+	unsigned int blklen;
+} __attribute__ ((packed));
+
+struct regcache_rbtree_ctx {
+	struct rb_root root;
+	struct regcache_rbtree_node *cached_rbnode;
+};
+
+static inline void regcache_rbtree_get_base_top_reg(
+	struct regcache_rbtree_node *rbnode,
+	unsigned int *base, unsigned int *top)
+{
+	*base = rbnode->base_reg;
+	*top = rbnode->base_reg + rbnode->blklen - 1;
+}
+
+static unsigned int regcache_rbtree_get_register(
+	struct regcache_rbtree_node *rbnode, unsigned int idx,
+	unsigned int word_size)
+{
+	return regcache_get_val(rbnode->block, idx, word_size);
+}
+
+static void regcache_rbtree_set_register(struct regcache_rbtree_node *rbnode,
+					 unsigned int idx, unsigned int val,
+					 unsigned int word_size)
+{
+	regcache_set_val(rbnode->block, idx, val, word_size);
+}
+
+static struct regcache_rbtree_node *regcache_rbtree_lookup(struct regmap *map,
+	unsigned int reg)
+{
+	struct regcache_rbtree_ctx *rbtree_ctx = map->cache;
+	struct rb_node *node;
+	struct regcache_rbtree_node *rbnode;
+	unsigned int base_reg, top_reg;
+
+	rbnode = rbtree_ctx->cached_rbnode;
+	if (rbnode) {
+		regcache_rbtree_get_base_top_reg(rbnode, &base_reg, &top_reg);
+		if (reg >= base_reg && reg <= top_reg)
+			return rbnode;
+	}
+
+	node = rbtree_ctx->root.rb_node;
+	while (node) {
+		rbnode = container_of(node, struct regcache_rbtree_node, node);
+		regcache_rbtree_get_base_top_reg(rbnode, &base_reg, &top_reg);
+		if (reg >= base_reg && reg <= top_reg) {
+			rbtree_ctx->cached_rbnode = rbnode;
+			return rbnode;
+		} else if (reg > top_reg) {
+			node = node->rb_right;
+		} else if (reg < base_reg) {
+			node = node->rb_left;
+		}
+	}
+
+	return NULL;
+}
+
+static int regcache_rbtree_insert(struct rb_root *root,
+				  struct regcache_rbtree_node *rbnode)
+{
+	struct rb_node **new, *parent;
+	struct regcache_rbtree_node *rbnode_tmp;
+	unsigned int base_reg_tmp, top_reg_tmp;
+	unsigned int base_reg;
+
+	parent = NULL;
+	new = &root->rb_node;
+	while (*new) {
+		rbnode_tmp = container_of(*new, struct regcache_rbtree_node,
+					  node);
+		/* base and top registers of the current rbnode */
+		regcache_rbtree_get_base_top_reg(rbnode_tmp, &base_reg_tmp,
+						 &top_reg_tmp);
+		/* base register of the rbnode to be added */
+		base_reg = rbnode->base_reg;
+		parent = *new;
+		/* if this register has already been inserted, just return */
+		if (base_reg >= base_reg_tmp &&
+		    base_reg <= top_reg_tmp)
+			return 0;
+		else if (base_reg > top_reg_tmp)
+			new = &((*new)->rb_right);
+		else if (base_reg < base_reg_tmp)
+			new = &((*new)->rb_left);
+	}
+
+	/* insert the node into the rbtree */
+	rb_link_node(&rbnode->node, parent, new);
+	rb_insert_color(&rbnode->node, root);
+
+	return 1;
+}
+
+static int regcache_rbtree_init(struct regmap *map)
+{
+	struct regcache_rbtree_ctx *rbtree_ctx;
+	int i;
+	int ret;
+
+	map->cache = kmalloc(sizeof *rbtree_ctx, GFP_KERNEL);
+	if (!map->cache)
+		return -ENOMEM;
+
+	rbtree_ctx = map->cache;
+	rbtree_ctx->root = RB_ROOT;
+	rbtree_ctx->cached_rbnode = NULL;
+
+	for (i = 0; i < map->num_reg_defaults; i++) {
+		ret = regcache_rbtree_write(map,
+					    map->reg_defaults[i].reg,
+					    map->reg_defaults[i].def);
+		if (ret)
+			goto err;
+	}
+
+	return 0;
+
+err:
+	regcache_exit(map);
+	return ret;
+}
+
+static int regcache_rbtree_exit(struct regmap *map)
+{
+	struct rb_node *next;
+	struct regcache_rbtree_ctx *rbtree_ctx;
+	struct regcache_rbtree_node *rbtree_node;
+
+	/* if we've already been called then just return */
+	rbtree_ctx = map->cache;
+	if (!rbtree_ctx)
+		return 0;
+
+	/* free up the rbtree */
+	next = rb_first(&rbtree_ctx->root);
+	while (next) {
+		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->block);
+		kfree(rbtree_node);
+	}
+
+	/* release the resources */
+	kfree(map->cache);
+	map->cache = NULL;
+
+	return 0;
+}
+
+static int regcache_rbtree_read(struct regmap *map,
+				unsigned int reg, unsigned int *value)
+{
+	struct regcache_rbtree_node *rbnode;
+	unsigned int reg_tmp;
+
+	rbnode = regcache_rbtree_lookup(map, reg);
+	if (rbnode) {
+		reg_tmp = reg - rbnode->base_reg;
+		*value = regcache_rbtree_get_register(rbnode, reg_tmp,
+						      map->cache_word_size);
+	} else {
+		return -ENOENT;
+	}
+
+	return 0;
+}
+
+
+static int regcache_rbtree_insert_to_block(struct regcache_rbtree_node *rbnode,
+					   unsigned int pos, unsigned int reg,
+					   unsigned int value, unsigned int word_size)
+{
+	u8 *blk;
+
+	blk = krealloc(rbnode->block,
+		       (rbnode->blklen + 1) * word_size, GFP_KERNEL);
+	if (!blk)
+		return -ENOMEM;
+
+	/* insert the register value in the correct place in the rbnode block */
+	memmove(blk + (pos + 1) * word_size,
+		blk + pos * word_size,
+		(rbnode->blklen - pos) * word_size);
+
+	/* update the rbnode block, its size and the base register */
+	rbnode->block = blk;
+	rbnode->blklen++;
+	if (!pos)
+		rbnode->base_reg = reg;
+
+	regcache_rbtree_set_register(rbnode, pos, value, word_size);
+	return 0;
+}
+
+static int regcache_rbtree_write(struct regmap *map, unsigned int reg,
+				 unsigned int value)
+{
+	struct regcache_rbtree_ctx *rbtree_ctx;
+	struct regcache_rbtree_node *rbnode, *rbnode_tmp;
+	struct rb_node *node;
+	unsigned int val;
+	unsigned int reg_tmp;
+	unsigned int pos;
+	int i;
+	int ret;
+
+	rbtree_ctx = map->cache;
+	/* if we can't locate it in the cached rbnode we'll have
+	 * to traverse the rbtree looking for it.
+	 */
+	rbnode = regcache_rbtree_lookup(map, reg);
+	if (rbnode) {
+		reg_tmp = reg - rbnode->base_reg;
+		val = regcache_rbtree_get_register(rbnode, reg_tmp,
+						   map->cache_word_size);
+		if (val == value)
+			return 0;
+		regcache_rbtree_set_register(rbnode, reg_tmp, value,
+					     map->cache_word_size);
+	} else {
+		/* 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;
+				if (abs(reg_tmp - reg) != 1)
+					continue;
+				/* decide where in the block to place our register */
+				if (reg_tmp + 1 == reg)
+					pos = i + 1;
+				else
+					pos = i;
+				ret = regcache_rbtree_insert_to_block(rbnode_tmp, pos,
+								      reg, value,
+								      map->cache_word_size);
+				if (ret)
+					return ret;
+				rbtree_ctx->cached_rbnode = rbnode_tmp;
+				return 0;
+			}
+		}
+		/* we did not manage to find a place to insert it in an existing
+		 * block so create a new rbnode with a single register in its block.
+		 * This block will get populated further if any other adjacent
+		 * registers get modified in the future.
+		 */
+		rbnode = kzalloc(sizeof *rbnode, GFP_KERNEL);
+		if (!rbnode)
+			return -ENOMEM;
+		rbnode->blklen = 1;
+		rbnode->base_reg = reg;
+		rbnode->block = kmalloc(rbnode->blklen * map->cache_word_size,
+					GFP_KERNEL);
+		if (!rbnode->block) {
+			kfree(rbnode);
+			return -ENOMEM;
+		}
+		regcache_rbtree_set_register(rbnode, 0, value, map->cache_word_size);
+		regcache_rbtree_insert(&rbtree_ctx->root, rbnode);
+		rbtree_ctx->cached_rbnode = rbnode;
+	}
+
+	return 0;
+}
+
+static int regcache_rbtree_sync(struct regmap *map)
+{
+	struct regcache_rbtree_ctx *rbtree_ctx;
+	struct rb_node *node;
+	struct regcache_rbtree_node *rbnode;
+	unsigned int regtmp;
+	unsigned int val;
+	int ret;
+	int i;
+
+	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);
+		for (i = 0; i < rbnode->blklen; i++) {
+			regtmp = rbnode->base_reg + i;
+			val = regcache_rbtree_get_register(rbnode, i,
+							   map->cache_word_size);
+
+			/* Is this the hardware default?  If so skip. */
+			ret = regcache_lookup_reg(map, i);
+			if (ret > 0 && val == map->reg_defaults[ret].def)
+				continue;
+
+			map->cache_bypass = 1;
+			ret = _regmap_write(map, regtmp, val);
+			map->cache_bypass = 0;
+			if (ret)
+				return ret;
+			dev_dbg(map->dev, "Synced register %#x, value %#x\n",
+				regtmp, val);
+		}
+	}
+
+	return 0;
+}
+
+struct regcache_ops regcache_rbtree_ops = {
+	.type = REGCACHE_RBTREE,
+	.name = "rbtree",
+	.init = regcache_rbtree_init,
+	.exit = regcache_rbtree_exit,
+	.read = regcache_rbtree_read,
+	.write = regcache_rbtree_write,
+	.sync = regcache_rbtree_sync
+};
diff --git a/drivers/base/regmap/regcache.c b/drivers/base/regmap/regcache.c
new file mode 100644
index 000000000000..afcfef838263
--- /dev/null
+++ b/drivers/base/regmap/regcache.c
@@ -0,0 +1,401 @@
+/*
+ * Register cache access API
+ *
+ * Copyright 2011 Wolfson Microelectronics plc
+ *
+ * Author: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/slab.h>
+#include <trace/events/regmap.h>
+#include <linux/bsearch.h>
+#include <linux/sort.h>
+