Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regmap

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regmap:
  regulator: Convert tps65023 to use regmap API
  regmap: Add SPI bus support
  regmap: Add I2C bus support
  regmap: Add generic non-memory mapped register access API

MAINTAINERS

@@ -5327,6 +5327,13 @@ L:	reiserfs-devel@vger.kernel.org
 S:	Supported
 F:	fs/reiserfs/
 
+REGISTER MAP ABSTRACTION
+M:	Mark Brown <broonie@opensource.wolfsonmicro.com>
+T:	git git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regmap.git
+S:	Supported
+F:	drivers/base/regmap/
+F:	include/linux/regmap.h
+
 RFKILL
 M:	Johannes Berg <johannes@sipsolutions.net>
 L:	linux-wireless@vger.kernel.org

drivers/base/Kconfig

@@ -168,4 +168,6 @@ config SYS_HYPERVISOR
 	bool
 	default n
 
+source "drivers/base/regmap/Kconfig"
+
 endmenu

drivers/base/Makefile

@@ -17,6 +17,7 @@ ifeq ($(CONFIG_SYSFS),y)
 obj-$(CONFIG_MODULES)	+= module.o
 endif
 obj-$(CONFIG_SYS_HYPERVISOR) += hypervisor.o
+obj-$(CONFIG_REGMAP)	+= regmap/
 
 ccflags-$(CONFIG_DEBUG_DRIVER) := -DDEBUG
 

drivers/base/regmap/Kconfig

+# Generic register map support.  There are no user servicable options here,
+# this is an API intended to be used by other kernel subsystems.  These
+# subsystems should select the appropriate symbols.
+
+config REGMAP
+	default y if (REGMAP_I2C || REGMAP_SPI)
+	bool
+
+config REGMAP_I2C
+	tristate
+
+config REGMAP_SPI
+	tristate

drivers/base/regmap/Makefile

+obj-$(CONFIG_REGMAP) += regmap.o
+obj-$(CONFIG_REGMAP_I2C) += regmap-i2c.o
+obj-$(CONFIG_REGMAP_SPI) += regmap-spi.o

drivers/base/regmap/regmap-i2c.c

+/*
+ * Register map access API - I2C support
+ *
+ * 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.
+ */
+
+#include <linux/regmap.h>
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/init.h>
+
+static int regmap_i2c_write(struct device *dev, const void *data, size_t count)
+{
+	struct i2c_client *i2c = to_i2c_client(dev);
+	int ret;
+
+	ret = i2c_master_send(i2c, data, count);
+	if (ret == count)
+		return 0;
+	else if (ret < 0)
+		return ret;
+	else
+		return -EIO;
+}
+
+static int regmap_i2c_gather_write(struct device *dev,
+				   const void *reg, size_t reg_size,
+				   const void *val, size_t val_size)
+{
+	struct i2c_client *i2c = to_i2c_client(dev);
+	struct i2c_msg xfer[2];
+	int ret;
+
+	/* If the I2C controller can't do a gather tell the core, it
+	 * will substitute in a linear write for us.
+	 */
+	if (!i2c_check_functionality(i2c->adapter, I2C_FUNC_PROTOCOL_MANGLING))
+		return -ENOTSUPP;
+
+	xfer[0].addr = i2c->addr;
+	xfer[0].flags = 0;
+	xfer[0].len = reg_size;
+	xfer[0].buf = (void *)reg;
+
+	xfer[1].addr = i2c->addr;
+	xfer[1].flags = I2C_M_NOSTART;
+	xfer[1].len = val_size;
+	xfer[1].buf = (void *)val;
+
+	ret = i2c_transfer(i2c->adapter, xfer, 2);
+	if (ret == 2)
+		return 0;
+	if (ret < 0)
+		return ret;
+	else
+		return -EIO;
+}
+
+static int regmap_i2c_read(struct device *dev,
+			   const void *reg, size_t reg_size,
+			   void *val, size_t val_size)
+{
+	struct i2c_client *i2c = to_i2c_client(dev);
+	struct i2c_msg xfer[2];
+	int ret;
+
+	xfer[0].addr = i2c->addr;
+	xfer[0].flags = 0;
+	xfer[0].len = reg_size;
+	xfer[0].buf = (void *)reg;
+
+	xfer[1].addr = i2c->addr;
+	xfer[1].flags = I2C_M_RD;
+	xfer[1].len = val_size;
+	xfer[1].buf = val;
+
+	ret = i2c_transfer(i2c->adapter, xfer, 2);
+	if (ret == 2)
+		return 0;
+	else if (ret < 0)
+		return ret;
+	else
+		return -EIO;
+}
+
+static struct regmap_bus regmap_i2c = {
+	.type = &i2c_bus_type,
+	.write = regmap_i2c_write,
+	.gather_write = regmap_i2c_gather_write,
+	.read = regmap_i2c_read,
+	.owner = THIS_MODULE,
+};
+
+/**
+ * regmap_init_i2c(): Initialise register map
+ *
+ * @i2c: Device that will be interacted with
+ * @config: Configuration for register map
+ *
+ * The return value will be an ERR_PTR() on error or a valid pointer to
+ * a struct regmap.
+ */
+struct regmap *regmap_init_i2c(struct i2c_client *i2c,
+			       const struct regmap_config *config)
+{
+	return regmap_init(&i2c->dev, &regmap_i2c, config);
+}
+EXPORT_SYMBOL_GPL(regmap_init_i2c);
+

drivers/base/regmap/regmap-spi.c

+/*
+ * Register map access API - SPI support
+ *
+ * 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.
+ */
+
+#include <linux/regmap.h>
+#include <linux/spi/spi.h>
+#include <linux/init.h>
+
+static int regmap_spi_write(struct device *dev, const void *data, size_t count)
+{
+	struct spi_device *spi = to_spi_device(dev);
+
+	return spi_write(spi, data, count);
+}
+
+static int regmap_spi_gather_write(struct device *dev,
+				   const void *reg, size_t reg_len,
+				   const void *val, size_t val_len)
+{
+	struct spi_device *spi = to_spi_device(dev);
+	struct spi_message m;
+	struct spi_transfer t[2] = { { .tx_buf = reg, .len = reg_len, },
+				     { .tx_buf = val, .len = val_len, }, };
+
+	spi_message_init(&m);
+	spi_message_add_tail(&t[0], &m);
+	spi_message_add_tail(&t[1], &m);
+
+	return spi_sync(spi, &m);
+}
+
+static int regmap_spi_read(struct device *dev,
+			   const void *reg, size_t reg_size,
+			   void *val, size_t val_size)
+{
+	struct spi_device *spi = to_spi_device(dev);
+
+	return spi_write_then_read(spi, reg, reg_size, val, val_size);
+}
+
+static struct regmap_bus regmap_spi = {
+	.type = &spi_bus_type,
+	.write = regmap_spi_write,
+	.gather_write = regmap_spi_gather_write,
+	.read = regmap_spi_read,
+	.owner = THIS_MODULE,
+	.read_flag_mask = 0x80,
+};
+
+/**
+ * regmap_init_spi(): Initialise register map
+ *
+ * @spi: Device that will be interacted with
+ * @config: Configuration for register map
+ *
+ * The return value will be an ERR_PTR() on error or a valid pointer to
+ * a struct regmap.
+ */
+struct regmap *regmap_init_spi(struct spi_device *spi,
+			       const struct regmap_config *config)
+{
+	return regmap_init(&spi->dev, &regmap_spi, config);
+}
+EXPORT_SYMBOL_GPL(regmap_init_spi);

drivers/base/regmap/regmap.c

+/*
+ * Register map access API
+ *
+ * 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.
+ */
+
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/err.h>
+
+#include <linux/regmap.h>
+
+struct regmap;
+
+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;
+};
+
+static void regmap_format_4_12_write(struct regmap *map,
+				     unsigned int reg, unsigned int val)
+{
+	__be16 *out = map->work_buf;
+	*out = cpu_to_be16((reg << 12) | val);
+}
+
+static void regmap_format_7_9_write(struct regmap *map,
+				    unsigned int reg, unsigned int val)
+{
+	__be16 *out = map->work_buf;
+	*out = cpu_to_be16((reg << 9) | val);
+}
+
+static void regmap_format_8(void *buf, unsigned int val)
+{
+	u8 *b = buf;
+
+	b[0] = val;
+}
+
+static void regmap_format_16(void *buf, unsigned int val)
+{
+	__be16 *b = buf;
+
+	b[0] = cpu_to_be16(val);
+}
+
+static unsigned int regmap_parse_8(void *buf)
+{
+	u8 *b = buf;
+
+	return b[0];
+}
+
+static unsigned int regmap_parse_16(void *buf)
+{
+	__be16 *b = buf;
+
+	b[0] = be16_to_cpu(b[0]);
+
+	return b[0];
+}
+
+/**
+ * regmap_init(): Initialise register map
+ *
+ * @dev: Device that will be interacted with
+ * @bus: Bus-specific callbacks to use with device
+ * @config: Configuration for register map
+ *
+ * The return value will be an ERR_PTR() on error or a valid pointer to
+ * a struct regmap.  This function should generally not be called
+ * directly, it should be called by bus-specific init functions.
+ */
+struct regmap *regmap_init(struct device *dev,
+			   const struct regmap_bus *bus,
+			   const struct regmap_config *config)
+{
+	struct regmap *map;
+	int ret = -EINVAL;
+
+	if (!bus || !config)
+		return NULL;
+
+	map = kzalloc(sizeof(*map), GFP_KERNEL);
+	if (map == NULL) {
+		ret = -ENOMEM;
+		goto err;
+	}
+
+	mutex_init(&map->lock);
+	map->format.buf_size = (config->reg_bits + config->val_bits) / 8;
+	map->format.reg_bytes = config->reg_bits / 8;
+	map->format.val_bytes = config->val_bits / 8;
+	map->dev = dev;
+	map->bus = bus;
+
+	switch (config->reg_bits) {
+	case 4:
+		switch (config->val_bits) {
+		case 12:
+			map->format.format_write = regmap_format_4_12_write;
+			break;
+		default:
+			goto err_map;
+		}
+		break;
+
+	case 7:
+		switch (config->val_bits) {
+		case 9:
+			map->format.format_write = regmap_format_7_9_write;
+			break;
+		default:
+			goto err_map;
+		}
+		break;
+
+	case 8:
+		map->format.format_reg = regmap_format_8;
+		break;
+
+	case 16:
+		map->format.format_reg = regmap_format_16;
+		break;
+
+	default:
+		goto err_map;
+	}
+
+	switch (config->val_bits) {
+	case 8:
+		map->format.format_val = regmap_format_8;
+		map->format.parse_val = regmap_parse_8;
+		break;
+	case 16:
+		map->format.format_val = regmap_format_16;
+		map->format.parse_val = regmap_parse_16;
+		break;
+	}
+
+	if (!map->format.format_write &&
+	    !(map->format.format_reg && map->format.format_val))
+		goto err_map;
+
+	map->work_buf = kmalloc(map->format.buf_size, GFP_KERNEL);
+	if (map->work_buf == NULL) {
+		ret = -ENOMEM;
+		goto err_bus;
+	}
+
+	return map;
+
+err_bus:
+	module_put(map->bus->owner);
+err_map:
+	kfree(map);
+err:
+	return ERR_PTR(ret);
+}
+EXPORT_SYMBOL_GPL(regmap_init);
+
+/**
+ * regmap_exit(): Free a previously allocated register map
+ */
+void regmap_exit(struct regmap *map)
+{
+	kfree(map->work_buf);
+	module_put(map->bus->owner);
+	kfree(map);
+}
+EXPORT_SYMBOL_GPL(regmap_exit);
+
+static int _regmap_raw_write(struct regmap *map, unsigned int reg,
+			     const void *val, size_t val_len)
+{
+	void *buf;
+	int ret = -ENOTSUPP;
+	size_t len;
+
+	map->format.format_reg(map->work_buf, reg);
+
+	/* Try to do a gather write if we can */
+	if (map->bus->gather_write)
+		ret = map->bus->gather_write(map->dev, map->work_buf,
+					     map->format.reg_bytes,
+					     val, val_len);
+
+	/* Otherwise fall back on linearising by hand. */
+	if (ret == -ENOTSUPP) {
+		len = map->format.reg_bytes + val_len;
+		buf = kmalloc(len, GFP_KERNEL);
+		if (!buf)
+			return -ENOMEM;
+
+		memcpy(buf, map->work_buf, map->format.reg_bytes);
+		memcpy(buf + map->format.reg_bytes, val, val_len);
+		ret = map->bus->write(map->dev, buf, len);
+
+		kfree(buf);
+	}
+
+	return ret;
+}
+
+static int _regmap_write(struct regmap *map, unsigned int reg,
+			 unsigned int val)
+{
+	BUG_ON(!map->format.format_write && !map->format.format_val);
+
+	if (map->format.format_write) {
+		map->format.format_write(map, reg, val);
+
+		return map->bus->write(map->dev, map->work_buf,
+				       map->format.buf_size);
+	} else {
+		map->format.format_val(map->work_buf + map->format.reg_bytes,
+				       val);
+		return _regmap_raw_write(map, reg,
+					 map->work_buf + map->format.reg_bytes,
+					 map->format.val_bytes);
+	}
+}
+
+/**
+ * regmap_write(): Write a value to a single register
+ *
+ * @map: Register map to write to
+ * @reg: Register to write to
+ * @val: Value to be written
+ *
+ * A value of zero will be returned on success, a negative errno will
+ * be returned in error cases.
+ */
+int regmap_write(struct regmap *map, unsigned int reg, unsigned int val)
+{
+	int ret;
+
+	mutex_lock(&map->lock);
+
+	ret = _regmap_write(map, reg, val);
+
+	mutex_unlock(&map->lock);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(regmap_write);
+
+/**
+ * regmap_raw_write(): Write raw values to one or more registers
+ *
+ * @map: Register map to write to
+ * @reg: Initial register to write to
+ * @val: Block of data to be written, laid out for direct transmission to the
+ *       device
+ * @val_len: Length of data pointed to by val.
+ *
+ * This function is intended to be used for things like firmware
+ * download where a large block of data needs to be transferred to the
+ * device.  No formatting will be done on the data provided.
+ *
+ * A value of zero will be returned on success, a negative errno will
+ * be returned in error cases.
+ */
+int regmap_raw_write(struct regmap *map, unsigned int reg,
+		     const void *val, size_t val_len)
+{
+	int ret;
+
+	mutex_lock(&map->lock);
+
+	ret = _regmap_raw_write(map, reg, val, val_len);
+
+	mutex_unlock(&map->lock);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(regmap_raw_write);
+
+static int _regmap_raw_read(struct regmap *map, unsigned int reg, void *val,
+			    unsigned int val_len)
+{
+	u8 *u8 = map->work_buf;
+	int ret;
+
+	map->format.format_reg(map->work_buf, reg);
+
+	/*
+	 * Some buses flag reads by setting the high bits in the
+	 * register addresss; since it's always the high bits for all
+	 * current formats we can do this here rather than in
+	 * formatting.  This may break if we get interesting formats.
+	 */
+	if (map->bus->read_flag_mask)
+		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);
+	if (ret != 0)
+		return ret;
+
+	return 0;
+}
+
+static int _regmap_read(struct regmap *map, unsigned int reg,
+			unsigned int *val)
+{
+	int ret;
+
+	if (!map->format.parse_val)
+		return -EINVAL;
+
+	ret = _regmap_raw_read(map, reg, map->work_buf, map->format.val_bytes);
+	if (ret == 0)
+		*val = map->format.parse_val(map->work_buf);
+
+	return ret;
+}
+
+/**
+ * regmap_read(): Read a value from a single register
+ *
+ * @map: Register map to write to
+ * @reg: Register to be read from
+ * @val: Pointer to store read value
+ *
+ * A value of zero will be returned on success, a negative errno will
+ * be returned in error cases.
+ */
+int regmap_read(struct regmap *map, unsigned int reg, unsigned int *val)
+{
+	int ret;
+
+	mutex_lock(&map->lock);
+
+	ret = _regmap_read(map, reg, val);
+
+	mutex_unlock(&map->lock);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(regmap_read);
+
+/**
+ * regmap_raw_read(): Read raw data from the device
+ *
+ * @map: Register map to write to
+ * @reg: First register to be read from
+ * @val: Pointer to store read value
+ * @val_len: Size of data to read
+ *
+ * A value of zero will be returned on success, a negative errno will
+ * be returned in error cases.
+ */
+int regmap_raw_read(struct regmap *map, unsigned int reg, void *val,
+		    size_t val_len)
+{
+	int ret;
+
+	mutex_lock(&map->lock);
+
+	ret = _regmap_raw_read(map, reg, val, val_len);
+
+	mutex_unlock(&map->lock);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(regmap_raw_read);
+
+/**
+ * regmap_bulk_read(): Read multiple registers from the device
+ *
+ * @map: Register map to write to
+ * @reg: First register to be read from
+ * @val: Pointer to store read value, in native register size for device
+ * @val_count: Number of registers to read
+ *
+ * A value of zero will be returned on success, a negative errno will
+ * be returned in error cases.
+ */
+int regmap_bulk_read(struct regmap *map, unsigned int reg, void *val,
+		     size_t val_count)
+{
+	int ret, i;
+	size_t val_bytes = map->format.val_bytes;
+
+	if (!map->format.parse_val)
+		return -EINVAL;
+
+	ret = regmap_raw_read(map, reg, val, val_bytes * val_count);
+	if (ret != 0)
+		return ret;
+
+	for (i = 0; i < val_count * val_bytes; i += val_bytes)
+		map->format.parse_val(val + i);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(regmap_bulk_read);
+
+/**
+ * remap_update_bits: Perform a read/modify/write cycle on the register map
+ *
+ * @map: Register map to update
+ * @reg: Register to update
+ * @mask: Bitmask to change
+ * @val: New value for bitmask
+ *
+ * Returns zero for success, a negative number on error.
+ */
+int regmap_update_bits(struct regmap *map, unsigned int reg,
+		       unsigned int mask, unsigned int val)
+{
+	int ret;
+	unsigned int tmp;
+
+	mutex_lock(&map->lock);
+
+	ret = _regmap_read(map, reg, &tmp);
+	if (ret != 0)
+		goto out;
+
+	tmp &= ~mask;
+	tmp |= val & mask;
+
+	ret = _regmap_write(map, reg, tmp);
+
+out:
+	mutex_unlock(&map->lock);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(regmap_update_bits);

drivers/regulator/Kconfig

@@ -235,6 +235,7 @@ config REGULATOR_TPS6105X
 config REGULATOR_TPS65023
 	tristate "TI TPS65023 Power regulators"
 	depends on I2C
+	select REGMAP_I2C
 	help
 	  This driver supports TPS65023 voltage regulator chips. TPS65023 provides
 	  three step-down converters and two general-purpose LDO voltage regulators.

drivers/regulator/tps65023-regulator.c

@@ -25,6 +25,7 @@
 #include <linux/i2c.h>
 #include <linux/delay.h>
 #include <linux/slab.h>
+#include <linux/regmap.h>
 
 /* Register definitions */
 #define	TPS65023_REG_VERSION		0
@@ -125,93 +126,35 @@ struct tps_pmic {
 	struct i2c_client *client;
 	struct regulator_dev *rdev[TPS65023_NUM_REGULATOR];
 	const struct tps_info *info[TPS65023_NUM_REGULATOR];
-	struct mutex io_lock;
+	struct regmap *regmap;
 };
 
-static inline int tps_65023_read(struct tps_pmic *tps, u8 reg)
-{
-	return i2c_smbus_read_byte_data(tps->client, reg);
-}
-
-static inline int tps_65023_write(struct tps_pmic *tps, u8 reg, u8 val)
-{
-	return i2c_smbus_write_byte_data(tps->client, reg, val);
-}
-
 static int tps_65023_set_bits(struct tps_pmic *tps, u8 reg, u8 mask)
 {
-	int err, data;
-
-	mutex_lock(&tps->io_lock);
-
-	data = tps_65023_read(tps, reg);
-	if (data < 0) {
-		dev_err(&tps->client->dev, "Read from reg 0x%x failed\n", reg);
-		err = data;
-		goto out;
-	}
-
-	data |= mask;
-	err = tps_65023_write(tps, reg, data);
-	if (err)
-		dev_err(&tps->client->dev, "Write for reg 0x%x failed\n", reg);
-
-out:
-	mutex_unlock(&tps->io_lock);
-	return err;
+	return regmap_update_bits(tps->regmap, reg, mask, mask);
 }
 
 static int tps_65023_clear_bits(struct tps_pmic *tps, u8 reg, u8 mask)
 {
-	int err, data;
-
-	mutex_lock(&tps->io_lock);
-
-	data = tps_65023_read(tps, reg);
-	if (data < 0) {
-		dev_err(&tps->client->dev, "Read from reg 0x%x failed\n", reg);
-		err = data;
-		goto out;
-	}
-
-	data &= ~mask;
-
-	err = tps_65023_write(tps, reg, data);
-	if (err)
-		dev_err(&tps->client->dev, "Write for reg 0x%x failed\n", reg);
-
-out:
-	mutex_unlock(&tps->io_lock);
-	return err;
-
+	return regmap_update_bits(tps->regmap, reg, mask, 0);
 }
 
 static int tps_65023_reg_read(struct tps_pmic *tps, u8 reg)
 {
-	int data;
+	unsigned int val;
+	int ret;
 
-	mutex_lock(&tps->io_lock);
+	ret = regmap_read(tps->regmap, reg, &val);
 
-	data = tps_65023_read(tps, reg);
-	if (data < 0)
-		dev_err(&tps->client->dev, "Read from reg 0x%x failed\n", reg);
-
-	mutex_unlock(&tps->io_lock);
-	return data;
+	if (ret != 0)
+		return ret;
+	else
+		return val;
 }
 
 static int tps_65023_reg_write(struct tps_pmic *tps, u8 reg, u8 val)
 {
-	int err;
-
-	mutex_lock(&tps->io_lock);
-
-	err = tps_65023_write(tps, reg, val);
-	if (err < 0)
-		dev_err(&tps->client->dev, "Write for reg 0x%x failed\n", reg);
-
-	mutex_unlock(&tps->io_lock);
-	return err;
+	return regmap_write(tps->regmap, reg, val);
 }
 
 static int tps65023_dcdc_is_enabled(struct regulator_dev *dev)
@@ -463,6 +406,11 @@ static struct regulator_ops tps65023_ldo_ops = {
 	.list_voltage = tps65023_ldo_list_voltage,
 };
 
+static struct regmap_config tps65023_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+};
+
 static int __devinit tps_65023_probe(struct i2c_client *client,
 				     const struct i2c_device_id *id)
 {
@@ -488,7 +436,13 @@ static int __devinit tps_65023_probe(struct i2c_client *client,
 	if (!tps)
 		return -ENOMEM;
 
-	mutex_init(&tps->io_lock);
+	tps->regmap = regmap_init_i2c(client, &tps65023_regmap_config);
+	if (IS_ERR(tps->regmap)) {
+		error = PTR_ERR(tps->regmap);
+		dev_err(&client->dev, "Failed to allocate register map: %d\n",
+			error);
+		goto fail_alloc;
+	}
 
 	/* common for all regulators */
 	tps->client = client;
@@ -527,6 +481,8 @@ static int __devinit tps_65023_probe(struct i2c_client *client,
 	while (--i >= 0)
 		regulator_unregister(tps->rdev[i]);
 
+	regmap_exit(tps->regmap);
+ fail_alloc:
 	kfree(tps);
 	return error;
 }
@@ -545,6 +501,7 @@ static int __devexit tps_65023_remove(struct i2c_client *client)
 	for (i = 0; i < TPS65023_NUM_REGULATOR; i++)
 		regulator_unregister(tps->rdev[i]);
 
+	regmap_exit(tps->regmap);
 	kfree(tps);
 
 	return 0;

include/linux/regmap.h

+#ifndef __LINUX_REGMAP_H
+#define __LINUX_REGMAP_H
+
+/*
+ * Register map access API
+ *
+ * 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.
+ */
+
+#include <linux/device.h>
+#include <linux/list.h>
+#include <linux/module.h>
+
+struct i2c_client;
+struct spi_device;
+
+struct regmap_config {
+	int reg_bits;
+	int val_bits;
+};
+
+typedef int (*regmap_hw_write)(struct device *dev, const void *data,
+			       size_t count);
+typedef int (*regmap_hw_gather_write)(struct device *dev,
+				      const void *reg, size_t reg_len,
+				      const void *val, size_t val_len);
+typedef int (*regmap_hw_read)(struct device *dev,
+			      const void *reg_buf, size_t reg_size,
+			      void *val_buf, size_t val_size);
+
+/**
+ * Description of a hardware bus for the register map infrastructure.
+ *
+ * @list: Internal use.
+ * @type: Bus type, used to identify bus to be used for a device.
+ * @write: Write operation.
+ * @gather_write: Write operation with split register/value, return -ENOTSUPP
+ *                if not implemented  on a given device.
+ * @read: Read operation.  Data is returned in the buffer used to transmit
+ *         data.
+ * @owner: Module with the bus implementation, used to pin the implementation
+ *         in memory.
+ * @read_flag_mask: Mask to be set in the top byte of the register when doing
+ *                  a read.
+ */
+struct regmap_bus {
+	struct list_head list;
+	struct bus_type *type;
+	regmap_hw_write write;
+	regmap_hw_gather_write gather_write;
+	regmap_hw_read read;
+	struct module *owner;
+	u8 read_flag_mask;
+};
+
+struct regmap *regmap_init(struct device *dev,
+			   const struct regmap_bus *bus,
+			   const struct regmap_config *config);
+struct regmap *regmap_init_i2c(struct i2c_client *i2c,
+			       const struct regmap_config *config);
+struct regmap *regmap_init_spi(struct spi_device *dev,
+			       const struct regmap_config *config);
+
+void regmap_exit(struct regmap *map);
+int regmap_write(struct regmap *map, unsigned int reg, unsigned int val);
+int regmap_raw_write(struct regmap *map, unsigned int reg,
+		     const void *val, size_t val_len);
+int regmap_read(struct regmap *map, unsigned int reg, unsigned int *val);
+int regmap_raw_read(struct regmap *map, unsigned int reg,
+		    void *val, size_t val_len);
+int regmap_bulk_read(struct regmap *map, unsigned int reg, void *val,
+		     size_t val_count);
+int regmap_update_bits(struct regmap *map, unsigned int reg,
+		       unsigned int mask, unsigned int val);
+
+#endif