regmap: fix NULL pointer dereference in _regmap_write/read

[deliverable/linux.git] / 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/device.h>
#include <linux/slab.h>
#include <linux/export.h>
#include <linux/mutex.h>
#include <linux/err.h>
#include <linux/rbtree.h>
#include <linux/sched.h>

#define CREATE_TRACE_POINTS
#include <trace/events/regmap.h>

#include "internal.h"

/*
 * Sometimes for failures during very early init the trace
 * infrastructure isn't available early enough to be used.  For this
 * sort of problem defining LOG_DEVICE will add printks for basic
 * register I/O on a specific device.
 */
#undef LOG_DEVICE

static int _regmap_update_bits(struct regmap *map, unsigned int reg,
                               unsigned int mask, unsigned int val,
                               bool *change);

static int _regmap_bus_reg_read(void *context, unsigned int reg,
                                unsigned int *val);
static int _regmap_bus_read(void *context, unsigned int reg,
                            unsigned int *val);
static int _regmap_bus_formatted_write(void *context, unsigned int reg,
                                       unsigned int val);
static int _regmap_bus_reg_write(void *context, unsigned int reg,
                                 unsigned int val);
static int _regmap_bus_raw_write(void *context, unsigned int reg,
                                 unsigned int val);

bool regmap_reg_in_ranges(unsigned int reg,
                          const struct regmap_range *ranges,
                          unsigned int nranges)
{
        const struct regmap_range *r;
        int i;

        for (i = 0, r = ranges; i < nranges; i++, r++)
                if (regmap_reg_in_range(reg, r))
                        return true;
        return false;
}
EXPORT_SYMBOL_GPL(regmap_reg_in_ranges);

bool regmap_check_range_table(struct regmap *map, unsigned int reg,
                              const struct regmap_access_table *table)
{
        /* Check "no ranges" first */
        if (regmap_reg_in_ranges(reg, table->no_ranges, table->n_no_ranges))
                return false;

        /* In case zero "yes ranges" are supplied, any reg is OK */
        if (!table->n_yes_ranges)
                return true;

        return regmap_reg_in_ranges(reg, table->yes_ranges,
                                    table->n_yes_ranges);
}
EXPORT_SYMBOL_GPL(regmap_check_range_table);

bool regmap_writeable(struct regmap *map, unsigned int reg)
{
        if (map->max_register && reg > map->max_register)
                return false;

        if (map->writeable_reg)
                return map->writeable_reg(map->dev, reg);

        if (map->wr_table)
                return regmap_check_range_table(map, reg, map->wr_table);

        return true;
}

bool regmap_readable(struct regmap *map, unsigned int reg)
{
        if (map->max_register && reg > map->max_register)
                return false;

        if (map->format.format_write)
                return false;

        if (map->readable_reg)
                return map->readable_reg(map->dev, reg);

        if (map->rd_table)
                return regmap_check_range_table(map, reg, map->rd_table);

        return true;
}

bool regmap_volatile(struct regmap *map, unsigned int reg)
{
        if (!regmap_readable(map, reg))
                return false;

        if (map->volatile_reg)
                return map->volatile_reg(map->dev, reg);

        if (map->volatile_table)
                return regmap_check_range_table(map, reg, map->volatile_table);

        if (map->cache_ops)
                return false;
        else
                return true;
}

bool regmap_precious(struct regmap *map, unsigned int reg)
{
        if (!regmap_readable(map, reg))
                return false;

        if (map->precious_reg)
                return map->precious_reg(map->dev, reg);

        if (map->precious_table)
                return regmap_check_range_table(map, reg, map->precious_table);

        return false;
}

static bool regmap_volatile_range(struct regmap *map, unsigned int reg,
        size_t num)
{
        unsigned int i;

        for (i = 0; i < num; i++)
                if (!regmap_volatile(map, reg + i))
                        return false;

        return true;
}

static void regmap_format_2_6_write(struct regmap *map,
                                     unsigned int reg, unsigned int val)
{
        u8 *out = map->work_buf;

        *out = (reg << 6) | val;
}

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_10_14_write(struct regmap *map,
                                    unsigned int reg, unsigned int val)
{
        u8 *out = map->work_buf;

        out[2] = val;
        out[1] = (val >> 8) | (reg << 6);
        out[0] = reg >> 2;
}

static void regmap_format_8(void *buf, unsigned int val, unsigned int shift)
{
        u8 *b = buf;

        b[0] = val << shift;
}

static void regmap_format_16_be(void *buf, unsigned int val, unsigned int shift)
{
        __be16 *b = buf;

        b[0] = cpu_to_be16(val << shift);
}

static void regmap_format_16_le(void *buf, unsigned int val, unsigned int shift)
{
        __le16 *b = buf;

        b[0] = cpu_to_le16(val << shift);
}

static void regmap_format_16_native(void *buf, unsigned int val,
                                    unsigned int shift)
{
        *(u16 *)buf = val << shift;
}

static void regmap_format_24(void *buf, unsigned int val, unsigned int shift)
{
        u8 *b = buf;

        val <<= shift;

        b[0] = val >> 16;
        b[1] = val >> 8;
        b[2] = val;
}

static void regmap_format_32_be(void *buf, unsigned int val, unsigned int shift)
{
        __be32 *b = buf;

        b[0] = cpu_to_be32(val << shift);
}

static void regmap_format_32_le(void *buf, unsigned int val, unsigned int shift)
{
        __le32 *b = buf;

        b[0] = cpu_to_le32(val << shift);
}

static void regmap_format_32_native(void *buf, unsigned int val,
                                    unsigned int shift)
{
        *(u32 *)buf = val << shift;
}

static void regmap_parse_inplace_noop(void *buf)
{
}

static unsigned int regmap_parse_8(const void *buf)
{
        const u8 *b = buf;

        return b[0];
}

static unsigned int regmap_parse_16_be(const void *buf)
{
        const __be16 *b = buf;

        return be16_to_cpu(b[0]);
}

static unsigned int regmap_parse_16_le(const void *buf)
{
        const __le16 *b = buf;

        return le16_to_cpu(b[0]);
}

static void regmap_parse_16_be_inplace(void *buf)
{
        __be16 *b = buf;

        b[0] = be16_to_cpu(b[0]);
}

static void regmap_parse_16_le_inplace(void *buf)
{
        __le16 *b = buf;

        b[0] = le16_to_cpu(b[0]);
}

static unsigned int regmap_parse_16_native(const void *buf)
{
        return *(u16 *)buf;
}

static unsigned int regmap_parse_24(const void *buf)
{
        const u8 *b = buf;
        unsigned int ret = b[2];
        ret |= ((unsigned int)b[1]) << 8;
        ret |= ((unsigned int)b[0]) << 16;

        return ret;
}

static unsigned int regmap_parse_32_be(const void *buf)
{
        const __be32 *b = buf;

        return be32_to_cpu(b[0]);
}

static unsigned int regmap_parse_32_le(const void *buf)
{
        const __le32 *b = buf;

        return le32_to_cpu(b[0]);
}

static void regmap_parse_32_be_inplace(void *buf)
{
        __be32 *b = buf;

        b[0] = be32_to_cpu(b[0]);
}

static void regmap_parse_32_le_inplace(void *buf)
{
        __le32 *b = buf;

        b[0] = le32_to_cpu(b[0]);
}

static unsigned int regmap_parse_32_native(const void *buf)
{
        return *(u32 *)buf;
}

static void regmap_lock_mutex(void *__map)
{
        struct regmap *map = __map;
        mutex_lock(&map->mutex);
}

static void regmap_unlock_mutex(void *__map)
{
        struct regmap *map = __map;
        mutex_unlock(&map->mutex);
}

static void regmap_lock_spinlock(void *__map)
__acquires(&map->spinlock)
{
        struct regmap *map = __map;
        unsigned long flags;

        spin_lock_irqsave(&map->spinlock, flags);
        map->spinlock_flags = flags;
}

static void regmap_unlock_spinlock(void *__map)
__releases(&map->spinlock)
{
        struct regmap *map = __map;
        spin_unlock_irqrestore(&map->spinlock, map->spinlock_flags);
}

static void dev_get_regmap_release(struct device *dev, void *res)
{
        /*
         * We don't actually have anything to do here; the goal here
         * is not to manage the regmap but to provide a simple way to
         * get the regmap back given a struct device.
         */
}

static bool _regmap_range_add(struct regmap *map,
                              struct regmap_range_node *data)
{
        struct rb_root *root = &map->range_tree;
        struct rb_node **new = &(root->rb_node), *parent = NULL;

        while (*new) {
                struct regmap_range_node *this =
                        container_of(*new, struct regmap_range_node, node);

                parent = *new;
                if (data->range_max < this->range_min)
                        new = &((*new)->rb_left);
                else if (data->range_min > this->range_max)
                        new = &((*new)->rb_right);
                else
                        return false;
        }

        rb_link_node(&data->node, parent, new);
        rb_insert_color(&data->node, root);

        return true;
}

static struct regmap_range_node *_regmap_range_lookup(struct regmap *map,
                                                      unsigned int reg)
{
        struct rb_node *node = map->range_tree.rb_node;

        while (node) {
                struct regmap_range_node *this =
                        container_of(node, struct regmap_range_node, node);

                if (reg < this->range_min)
                        node = node->rb_left;
                else if (reg > this->range_max)
                        node = node->rb_right;
                else
                        return this;
        }

        return NULL;
}

static void regmap_range_exit(struct regmap *map)
{
        struct rb_node *next;
        struct regmap_range_node *range_node;

        next = rb_first(&map->range_tree);
        while (next) {
                range_node = rb_entry(next, struct regmap_range_node, node);
                next = rb_next(&range_node->node);
                rb_erase(&range_node->node, &map->range_tree);
                kfree(range_node);
        }

        kfree(map->selector_work_buf);
}

int regmap_attach_dev(struct device *dev, struct regmap *map,
                      const struct regmap_config *config)
{
        struct regmap **m;

        map->dev = dev;

        regmap_debugfs_init(map, config->name);

        /* Add a devres resource for dev_get_regmap() */
        m = devres_alloc(dev_get_regmap_release, sizeof(*m), GFP_KERNEL);
        if (!m) {
                regmap_debugfs_exit(map);
                return -ENOMEM;
        }
        *m = map;
        devres_add(dev, m);

        return 0;
}
EXPORT_SYMBOL_GPL(regmap_attach_dev);

/**
 * regmap_init(): Initialise register map
 *
 * @dev: Device that will be interacted with
 * @bus: Bus-specific callbacks to use with device
 * @bus_context: Data passed to bus-specific callbacks
 * @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,
                           void *bus_context,
                           const struct regmap_config *config)
{
        struct regmap *map;
        int ret = -EINVAL;
        enum regmap_endian reg_endian, val_endian;
        int i, j;

        if (!config)
                goto err;

        map = kzalloc(sizeof(*map), GFP_KERNEL);
        if (map == NULL) {
                ret = -ENOMEM;
                goto err;
        }

        if (config->lock && config->unlock) {
                map->lock = config->lock;
                map->unlock = config->unlock;
                map->lock_arg = config->lock_arg;
        } else {
                if ((bus && bus->fast_io) ||
                    config->fast_io) {
                        spin_lock_init(&map->spinlock);
                        map->lock = regmap_lock_spinlock;
                        map->unlock = regmap_unlock_spinlock;
                } else {
                        mutex_init(&map->mutex);
                        map->lock = regmap_lock_mutex;
                        map->unlock = regmap_unlock_mutex;
                }
                map->lock_arg = map;
        }
        map->format.reg_bytes = DIV_ROUND_UP(config->reg_bits, 8);
        map->format.pad_bytes = config->pad_bits / 8;
        map->format.val_bytes = DIV_ROUND_UP(config->val_bits, 8);
        map->format.buf_size = DIV_ROUND_UP(config->reg_bits +
                        config->val_bits + config->pad_bits, 8);
        map->reg_shift = config->pad_bits % 8;
        if (config->reg_stride)
                map->reg_stride = config->reg_stride;
        else
                map->reg_stride = 1;
        map->use_single_rw = config->use_single_rw;
        map->can_multi_write = config->can_multi_write;
        map->dev = dev;
        map->bus = bus;
        map->bus_context = bus_context;
        map->max_register = config->max_register;
        map->wr_table = config->wr_table;
        map->rd_table = config->rd_table;
        map->volatile_table = config->volatile_table;
        map->precious_table = config->precious_table;
        map->writeable_reg = config->writeable_reg;
        map->readable_reg = config->readable_reg;
        map->volatile_reg = config->volatile_reg;
        map->precious_reg = config->precious_reg;
        map->cache_type = config->cache_type;
        map->name = config->name;

        spin_lock_init(&map->async_lock);
        INIT_LIST_HEAD(&map->async_list);
        INIT_LIST_HEAD(&map->async_free);
        init_waitqueue_head(&map->async_waitq);

        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 if (bus) {
                map->read_flag_mask = bus->read_flag_mask;
        }

        if (!bus) {
                map->reg_read  = config->reg_read;
                map->reg_write = config->reg_write;

                map->defer_caching = false;
                goto skip_format_initialization;
        } else if (!bus->read || !bus->write) {
                map->reg_read = _regmap_bus_reg_read;
                map->reg_write = _regmap_bus_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)
                reg_endian = bus->reg_format_endian_default;
        if (reg_endian == REGMAP_ENDIAN_DEFAULT)
                reg_endian = REGMAP_ENDIAN_BIG;

        val_endian = config->val_format_endian;
        if (val_endian == REGMAP_ENDIAN_DEFAULT)
                val_endian = bus->val_format_endian_default;
        if (val_endian == REGMAP_ENDIAN_DEFAULT)
                val_endian = REGMAP_ENDIAN_BIG;

        switch (config->reg_bits + map->reg_shift) {
        case 2:
                switch (config->val_bits) {
                case 6:
                        map->format.format_write = regmap_format_2_6_write;
                        break;
                default:
                        goto err_map;
                }
                break;

        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 10:
                switch (config->val_bits) {
                case 14:
                        map->format.format_write = regmap_format_10_14_write;
                        break;
                default:
                        goto err_map;
                }
                break;

        case 8:
                map->format.format_reg = regmap_format_8;
                break;

        case 16:
                switch (reg_endian) {
                case REGMAP_ENDIAN_BIG:
                        map->format.format_reg = regmap_format_16_be;
                        break;
                case REGMAP_ENDIAN_NATIVE:
                        map->format.format_reg = regmap_format_16_native;
                        break;
                default:
                        goto err_map;
                }
                break;

        case 24:
                if (reg_endian != REGMAP_ENDIAN_BIG)
                        goto err_map;
                map->format.format_reg = regmap_format_24;
                break;

        case 32:
                switch (reg_endian) {
                case REGMAP_ENDIAN_BIG:
                        map->format.format_reg = regmap_format_32_be;
                        break;
                case REGMAP_ENDIAN_NATIVE:
                        map->format.format_reg = regmap_format_32_native;
                        break;
                default:
                        goto err_map;
                }
                break;

        default:
                goto err_map;
        }

        if (val_endian == REGMAP_ENDIAN_NATIVE)
                map->format.parse_inplace = regmap_parse_inplace_noop;

        switch (config->val_bits) {
        case 8:
                map->format.format_val = regmap_format_8;
                map->format.parse_val = regmap_parse_8;
                map->format.parse_inplace = regmap_parse_inplace_noop;
                break;
        case 16:
                switch (val_endian) {
                case REGMAP_ENDIAN_BIG:
                        map->format.format_val = regmap_format_16_be;
                        map->format.parse_val = regmap_parse_16_be;
                        map->format.parse_inplace = regmap_parse_16_be_inplace;
                        break;
                case REGMAP_ENDIAN_LITTLE:
                        map->format.format_val = regmap_format_16_le;
                        map->format.parse_val = regmap_parse_16_le;
                        map->format.parse_inplace = regmap_parse_16_le_inplace;
                        break;
                case REGMAP_ENDIAN_NATIVE:
                        map->format.format_val = regmap_format_16_native;
                        map->format.parse_val = regmap_parse_16_native;
                        break;
                default:
                        goto err_map;
                }
                break;
        case 24:
                if (val_endian != REGMAP_ENDIAN_BIG)
                        goto err_map;
                map->format.format_val = regmap_format_24;
                map->format.parse_val = regmap_parse_24;
                break;
        case 32:
                switch (val_endian) {
                case REGMAP_ENDIAN_BIG:
                        map->format.format_val = regmap_format_32_be;
                        map->format.parse_val = regmap_parse_32_be;
                        map->format.parse_inplace = regmap_parse_32_be_inplace;
                        break;
                case REGMAP_ENDIAN_LITTLE:
                        map->format.format_val = regmap_format_32_le;
                        map->format.parse_val = regmap_parse_32_le;
                        map->format.parse_inplace = regmap_parse_32_le_inplace;
                        break;
                case REGMAP_ENDIAN_NATIVE:
                        map->format.format_val = regmap_format_32_native;
                        map->format.parse_val = regmap_parse_32_native;
                        break;
                default:
                        goto err_map;
                }
                break;
        }

        if (map->format.format_write) {
                if ((reg_endian != REGMAP_ENDIAN_BIG) ||
                    (val_endian != REGMAP_ENDIAN_BIG))
                        goto err_map;
                map->use_single_rw = true;
        }

        if (!map->format.format_write &&
            !(map->format.format_reg && map->format.format_val))
                goto err_map;

        map->work_buf = kzalloc(map->format.buf_size, GFP_KERNEL);
        if (map->work_buf == NULL) {
                ret = -ENOMEM;
                goto err_map;
        }

        if (map->format.format_write) {
                map->defer_caching = false;
                map->reg_write = _regmap_bus_formatted_write;
        } 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++) {
                const struct regmap_range_cfg *range_cfg = &config->ranges[i];
                struct regmap_range_node *new;

                /* Sanity check */
                if (range_cfg->range_max < range_cfg->range_min) {
                        dev_err(map->dev, "Invalid range %d: %d < %d\n", i,
                                range_cfg->range_max, range_cfg->range_min);
                        goto err_range;
                }

                if (range_cfg->range_max > map->max_register) {
                        dev_err(map->dev, "Invalid range %d: %d > %d\n", i,
                                range_cfg->range_max, map->max_register);
                        goto err_range;
                }

                if (range_cfg->selector_reg > map->max_register) {
                        dev_err(map->dev,
                                "Invalid range %d: selector out of map\n", i);
                        goto err_range;
                }

                if (range_cfg->window_len == 0) {
                        dev_err(map->dev, "Invalid range %d: window_len 0\n",
                                i);
                        goto err_range;
                }

                /* Make sure, that this register range has no selector
                   or data window within its boundary */
                for (j = 0; j < config->num_ranges; j++) {
                        unsigned sel_reg = config->ranges[j].selector_reg;
                        unsigned win_min = config->ranges[j].window_start;
                        unsigned win_max = win_min +
                                           config->ranges[j].window_len - 1;

                        /* Allow data window inside its own virtual range */
                        if (j == i)
                                continue;

                        if (range_cfg->range_min <= sel_reg &&
                            sel_reg <= range_cfg->range_max) {
                                dev_err(map->dev,
                                        "Range %d: selector for %d in window\n",
                                        i, j);
                                goto err_range;
                        }

                        if (!(win_max < range_cfg->range_min ||
                              win_min > range_cfg->range_max)) {
                                dev_err(map->dev,
                                        "Range %d: window for %d in window\n",
                                        i, j);
                                goto err_range;
                        }
                }

                new = kzalloc(sizeof(*new), GFP_KERNEL);
                if (new == NULL) {
                        ret = -ENOMEM;
                        goto err_range;
                }

                new->map = map;
                new->name = range_cfg->name;
                new->range_min = range_cfg->range_min;
                new->range_max = range_cfg->range_max;
                new->selector_reg = range_cfg->selector_reg;
                new->selector_mask = range_cfg->selector_mask;
                new->selector_shift = range_cfg->selector_shift;
                new->window_start = range_cfg->window_start;
                new->window_len = range_cfg->window_len;

                if (!_regmap_range_add(map, new)) {
                        dev_err(map->dev, "Failed to add range %d\n", i);
                        kfree(new);
                        goto err_range;
                }

                if (map->selector_work_buf == NULL) {
                        map->selector_work_buf =
                                kzalloc(map->format.buf_size, GFP_KERNEL);
                        if (map->selector_work_buf == NULL) {
                                ret = -ENOMEM;
                                goto err_range;
                        }
                }
        }

        ret = regcache_init(map, config);
        if (ret != 0)
                goto err_range;

        if (dev) {
                ret = regmap_attach_dev(dev, map, config);
                if (ret != 0)
                        goto err_regcache;
        }

        return map;

err_regcache:
        regcache_exit(map);
err_range:
        regmap_range_exit(map);
        kfree(map->work_buf);
err_map:
        kfree(map);
err:
        return ERR_PTR(ret);
}
EXPORT_SYMBOL_GPL(regmap_init);

static void devm_regmap_release(struct device *dev, void *res)
{
        regmap_exit(*(struct regmap **)res);
}

/**
 * devm_regmap_init(): Initialise managed register map
 *
 * @dev: Device that will be interacted with
 * @bus: Bus-specific callbacks to use with device
 * @bus_context: Data passed to bus-specific callbacks
 * @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.  The
 * map will be automatically freed by the device management code.
 */
struct regmap *devm_regmap_init(struct device *dev,
                                const struct regmap_bus *bus,
                                void *bus_context,
                                const struct regmap_config *config)
{
        struct regmap **ptr, *regmap;

        ptr = devres_alloc(devm_regmap_release, sizeof(*ptr), GFP_KERNEL);
        if (!ptr)
                return ERR_PTR(-ENOMEM);

        regmap = regmap_init(dev, bus, bus_context, config);
        if (!IS_ERR(regmap)) {
                *ptr = regmap;
                devres_add(dev, ptr);
        } else {
                devres_free(ptr);
        }

        return regmap;
}
EXPORT_SYMBOL_GPL(devm_regmap_init);

static void regmap_field_init(struct regmap_field *rm_field,
        struct regmap *regmap, struct reg_field reg_field)
{
        int field_bits = reg_field.msb - reg_field.lsb + 1;
        rm_field->regmap = regmap;
        rm_field->reg = reg_field.reg;
        rm_field->shift = reg_field.lsb;
        rm_field->mask = ((BIT(field_bits) - 1) << reg_field.lsb);
        rm_field->id_size = reg_field.id_size;
        rm_field->id_offset = reg_field.id_offset;
}

/**
 * devm_regmap_field_alloc(): Allocate and initialise a register field
 * in a register map.
 *
 * @dev: Device that will be interacted with
 * @regmap: regmap bank in which this register field is located.
 * @reg_field: Register field with in the bank.
 *
 * The return value will be an ERR_PTR() on error or a valid pointer
 * to a struct regmap_field. The regmap_field will be automatically freed
 * by the device management code.
 */
struct regmap_field *devm_regmap_field_alloc(struct device *dev,
                struct regmap *regmap, struct reg_field reg_field)
{
        struct regmap_field *rm_field = devm_kzalloc(dev,
                                        sizeof(*rm_field), GFP_KERNEL);
        if (!rm_field)
                return ERR_PTR(-ENOMEM);

        regmap_field_init(rm_field, regmap, reg_field);

        return rm_field;

}
EXPORT_SYMBOL_GPL(devm_regmap_field_alloc);

/**
 * devm_regmap_field_free(): Free register field allocated using
 * devm_regmap_field_alloc. Usally drivers need not call this function,
 * as the memory allocated via devm will be freed as per device-driver
 * life-cyle.
 *
 * @dev: Device that will be interacted with
 * @field: regmap field which should be freed.
 */
void devm_regmap_field_free(struct device *dev,
        struct regmap_field *field)
{
        devm_kfree(dev, field);
}
EXPORT_SYMBOL_GPL(devm_regmap_field_free);

/**
 * regmap_field_alloc(): Allocate and initialise a register field
 * in a register map.
 *
 * @regmap: regmap bank in which this register field is located.
 * @reg_field: Register field with in the bank.
 *
 * The return value will be an ERR_PTR() on error or a valid pointer
 * to a struct regmap_field. The regmap_field should be freed by the
 * user once its finished working with it using regmap_field_free().
 */
struct regmap_field *regmap_field_alloc(struct regmap *regmap,
                struct reg_field reg_field)
{
        struct regmap_field *rm_field = kzalloc(sizeof(*rm_field), GFP_KERNEL);

        if (!rm_field)
                return ERR_PTR(-ENOMEM);

        regmap_field_init(rm_field, regmap, reg_field);

        return rm_field;
}
EXPORT_SYMBOL_GPL(regmap_field_alloc);

/**
 * regmap_field_free(): Free register field allocated using regmap_field_alloc
 *
 * @field: regmap field which should be freed.
 */
void regmap_field_free(struct regmap_field *field)
{
        kfree(field);
}
EXPORT_SYMBOL_GPL(regmap_field_free);

/**
 * regmap_reinit_cache(): Reinitialise the current register cache
 *
 * @map: Register map to operate on.
 * @config: New configuration.  Only the cache data will be used.
 *
 * Discard any existing register cache for the map and initialize a
 * new cache.  This can be used to restore the cache to defaults or to
 * update the cache configuration to reflect runtime discovery of the
 * hardware.
 *
 * No explicit locking is done here, the user needs to ensure that
 * this function will not race with other calls to regmap.
 */
int regmap_reinit_cache(struct regmap *map, const struct regmap_config *config)
{
        regcache_exit(map);
        regmap_debugfs_exit(map);

        map->max_register = config->max_register;
        map->writeable_reg = config->writeable_reg;
        map->readable_reg = config->readable_reg;
        map->volatile_reg = config->volatile_reg;
        map->precious_reg = config->precious_reg;
        map->cache_type = config->cache_type;

        regmap_debugfs_init(map, config->name);

        map->cache_bypass = false;
        map->cache_only = false;

        return regcache_init(map, config);
}
EXPORT_SYMBOL_GPL(regmap_reinit_cache);

/**
 * regmap_exit(): Free a previously allocated register map
 */
void regmap_exit(struct regmap *map)
{
        struct regmap_async *async;

        regcache_exit(map);
        regmap_debugfs_exit(map);
        regmap_range_exit(map);
        if (map->bus && map->bus->free_context)
                map->bus->free_context(map->bus_context);
        kfree(map->work_buf);
        while (!list_empty(&map->async_free)) {
                async = list_first_entry_or_null(&map->async_free,
                                                 struct regmap_async,
                                                 list);
                list_del(&async->list);
                kfree(async->work_buf);
                kfree(async);
        }
        kfree(map);
}
EXPORT_SYMBOL_GPL(regmap_exit);

static int dev_get_regmap_match(struct device *dev, void *res, void *data)
{
        struct regmap **r = res;
        if (!r || !*r) {
                WARN_ON(!r || !*r);
                return 0;
        }

        /* If the user didn't specify a name match any */
        if (data)
                return (*r)->name == data;
        else
                return 1;
}

/**
 * dev_get_regmap(): Obtain the regmap (if any) for a device
 *
 * @dev: Device to retrieve the map for
 * @name: Optional name for the register map, usually NULL.
 *
 * Returns the regmap for the device if one is present, or NULL.  If
 * name is specified then it must match the name specified when
 * registering the device, if it is NULL then the first regmap found
 * will be used.  Devices with multiple register maps are very rare,
 * generic code should normally not need to specify a name.
 */
struct regmap *dev_get_regmap(struct device *dev, const char *name)
{
        struct regmap **r = devres_find(dev, dev_get_regmap_release,
                                        dev_get_regmap_match, (void *)name);

        if (!r)
                return NULL;
        return *r;
}
EXPORT_SYMBOL_GPL(dev_get_regmap);

/**
 * regmap_get_device(): Obtain the device from a regmap
 *
 * @map: Register map to operate on.
 *
 * Returns the underlying device that the regmap has been created for.
 */
struct device *regmap_get_device(struct regmap *map)
{
        return map->dev;
}
EXPORT_SYMBOL_GPL(regmap_get_device);

static int _regmap_select_page(struct regmap *map, unsigned int *reg,
                               struct regmap_range_node *range,
                               unsigned int val_num)
{
        void *orig_work_buf;
        unsigned int win_offset;
        unsigned int win_page;
        bool page_chg;
        int ret;

        win_offset = (*reg - range->range_min) % range->window_len;
        win_page = (*reg - range->range_min) / range->window_len;

        if (val_num > 1) {
                /* Bulk write shouldn't cross range boundary */
                if (*reg + val_num - 1 > range->range_max)
                        return -EINVAL;

                /* ... or single page boundary */
                if (val_num > range->window_len - win_offset)
                        return -EINVAL;
        }

        /* It is possible to have selector register inside data window.
           In that case, selector register is located on every page and
           it needs no page switching, when accessed alone. */
        if (val_num > 1 ||
            range->window_start + win_offset != range->selector_reg) {
                /* Use separate work_buf during page switching */
                orig_work_buf = map->work_buf;
                map->work_buf = map->selector_work_buf;

                ret = _regmap_update_bits(map, range->selector_reg,
                                          range->selector_mask,
                                          win_page << range->selector_shift,
                                          &page_chg);

                map->work_buf = orig_work_buf;

                if (ret != 0)
                        return ret;
        }

        *reg = range->window_start + win_offset;

        return 0;
}

int _regmap_raw_write(struct regmap *map, unsigned int reg,
                      const void *val, size_t val_len)
{
        struct regmap_range_node *range;
        unsigned long flags;
        u8 *u8 = map->work_buf;
        void *work_val = map->work_buf + map->format.reg_bytes +
                map->format.pad_bytes;
        void *buf;
        int ret = -ENOTSUPP;
        size_t len;
        int i;

        WARN_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++)
                        if (!map->writeable_reg(map->dev,
                                                reg + (i * map->reg_stride)))
                                return -EINVAL;

        if (!map->cache_bypass && map->format.parse_val) {
                unsigned int ival;
                int val_bytes = map->format.val_bytes;
                for (i = 0; i < val_len / val_bytes; i++) {
                        ival = map->format.parse_val(val + (i * val_bytes));
                        ret = regcache_write(map, reg + (i * map->reg_stride),
                                             ival);
                        if (ret) {
                                dev_err(map->dev,
                                        "Error in caching of register: %x ret: %d\n",
                                        reg + i, ret);
                                return ret;
                        }
                }
                if (map->cache_only) {
                        map->cache_dirty = true;
                        return 0;
                }
        }

        range = _regmap_range_lookup(map, reg);
        if (range) {
                int val_num = val_len / map->format.val_bytes;
                int win_offset = (reg - range->range_min) % range->window_len;
                int win_residue = range->window_len - win_offset;

                /* If the write goes beyond the end of the window split it */
                while (val_num > win_residue) {
                        dev_dbg(map->dev, "Writing window %d/%zu\n",
                                win_residue, val_len / map->format.val_bytes);
                        ret = _regmap_raw_write(map, reg, val, win_residue *
                                                map->format.val_bytes);
                        if (ret != 0)
                                return ret;

                        reg += win_residue;
                        val_num -= win_residue;
                        val += win_residue * map->format.val_bytes;
                        val_len -= win_residue * map->format.val_bytes;

                        win_offset = (reg - range->range_min) %
                                range->window_len;
                        win_residue = range->window_len - win_offset;
                }

                ret = _regmap_select_page(map, &reg, range, val_num);
                if (ret != 0)
                        return ret;
        }

        map->format.format_reg(map->work_buf, reg, map->reg_shift);

        u8[0] |= map->write_flag_mask;

        /*
         * Essentially all I/O mechanisms will be faster with a single
         * buffer to write.  Since register syncs often generate raw
         * writes of single registers optimise that case.
         */
        if (val != work_val && val_len == map->format.val_bytes) {
                memcpy(work_val, val, map->format.val_bytes);
                val = work_val;
        }

        if (map->async && map->bus->async_write) {
                struct regmap_async *async;

                trace_regmap_async_write_start(map->dev, reg, val_len);

                spin_lock_irqsave(&map->async_lock, flags);
                async = list_first_entry_or_null(&map->async_free,
                                                 struct regmap_async,
                                                 list);
                if (async)
                        list_del(&async->list);
                spin_unlock_irqrestore(&map->async_lock, flags);

                if (!async) {
                        async = map->bus->async_alloc();
                        if (!async)
                                return -ENOMEM;

                        async->work_buf = kzalloc(map->format.buf_size,
                                                  GFP_KERNEL | GFP_DMA);
                        if (!async->work_buf) {
                                kfree(async);
                                return -ENOMEM;
                        }
                }

                async->map = map;

                /* If the caller supplied the value we can use it safely. */
                memcpy(async->work_buf, map->work_buf, map->format.pad_bytes +
                       map->format.reg_bytes + map->format.val_bytes);

                spin_lock_irqsave(&map->async_lock, flags);
                list_add_tail(&async->list, &map->async_list);
                spin_unlock_irqrestore(&map->async_lock, flags);

                if (val != work_val)
                        ret = map->bus->async_write(map->bus_context,
                                                    async->work_buf,
                                                    map->format.reg_bytes +
                                                    map->format.pad_bytes,
                                                    val, val_len, async);
                else
                        ret = map->bus->async_write(map->bus_context,
                                                    async->work_buf,
                                                    map->format.reg_bytes +
                                                    map->format.pad_bytes +
                                                    val_len, NULL, 0, async);

                if (ret != 0) {
                        dev_err(map->dev, "Failed to schedule write: %d\n",
                                ret);

                        spin_lock_irqsave(&map->async_lock, flags);
                        list_move(&async->list, &map->async_free);
                        spin_unlock_irqrestore(&map->async_lock, flags);
                }

                return ret;
        }

        trace_regmap_hw_write_start(map->dev, reg,
                                    val_len / map->format.val_bytes);

        /* If we're doing a single register write we can probably just
         * send the work_buf directly, otherwise try to do a gather
         * write.
         */
        if (val == work_val)
                ret = map->bus->write(map->bus_context, map->work_buf,
                                      map->format.reg_bytes +
                                      map->format.pad_bytes +
                                      val_len);
        else if (map->bus->gather_write)
                ret = map->bus->gather_write(map->bus_context, map->work_buf,
                                             map->format.reg_bytes +
                                             map->format.pad_bytes,
                                             val, val_len);

        /* If that didn't work fall back on linearising by hand. */
        if (ret == -ENOTSUPP) {
                len = map->format.reg_bytes + map->format.pad_bytes + val_len;
                buf = kzalloc(len, GFP_KERNEL);
                if (!buf)
                        return -ENOMEM;

                memcpy(buf, map->work_buf, map->format.reg_bytes);
                memcpy(buf + map->format.reg_bytes + map->format.pad_bytes,
                       val, val_len);
                ret = map->bus->write(map->bus_context, buf, len);

                kfree(buf);
        }

        trace_regmap_hw_write_done(map->dev, reg,
                                   val_len / map->format.val_bytes);

        return ret;
}

/**
 * regmap_can_raw_write - Test if regmap_raw_write() is supported
 *
 * @map: Map to check.
 */
bool regmap_can_raw_write(struct regmap *map)
{
        return map->bus && map->format.format_val && map->format.format_reg;
}
EXPORT_SYMBOL_GPL(regmap_can_raw_write);

static int _regmap_bus_formatted_write(void *context, unsigned int reg,
                                       unsigned int val)
{
        int ret;
        struct regmap_range_node *range;
        struct regmap *map = context;

        WARN_ON(!map->bus || !map->format.format_write);

        range = _regmap_range_lookup(map, reg);
        if (range) {
                ret = _regmap_select_page(map, &reg, range, 1);
                if (ret != 0)
                        return ret;
        }

        map->format.format_write(map, reg, val);

        trace_regmap_hw_write_start(map->dev, reg, 1);

        ret = map->bus->write(map->bus_context, map->work_buf,
                              map->format.buf_size);

        trace_regmap_hw_write_done(map->dev, reg, 1);

        return ret;
}

static int _regmap_bus_reg_write(void *context, unsigned int reg,
                                 unsigned int val)
{
        struct regmap *map = context;

        return map->bus->reg_write(map->bus_context, reg, val);
}

static int _regmap_bus_raw_write(void *context, unsigned int reg,
                                 unsigned int val)
{
        struct regmap *map = context;

        WARN_ON(!map->bus || !map->format.format_val);

        map->format.format_val(map->work_buf + map->format.reg_bytes
                               + map->format.pad_bytes, val, 0);
        return _regmap_raw_write(map, reg,
                                 map->work_buf +
                                 map->format.reg_bytes +
                                 map->format.pad_bytes,
                                 map->format.val_bytes);
}

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 (!regmap_writeable(map, reg))
                return -EIO;

        if (!map->cache_bypass && !map->defer_caching) {
                ret = regcache_write(map, reg, val);
                if (ret != 0)
                        return ret;
                if (map->cache_only) {
                        map->cache_dirty = true;
                        return 0;
                }
        }

#ifdef LOG_DEVICE
        if (map->dev && strcmp(dev_name(map->dev), LOG_DEVICE) == 0)
                dev_info(map->dev, "%x <= %x\n", reg, val);
#endif

        trace_regmap_reg_write(map->dev, reg, val);

        return map->reg_write(context, reg, val);
}

/**
 * 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;

        if (reg % map->reg_stride)
                return -EINVAL;

        map->lock(map->lock_arg);

        ret = _regmap_write(map, reg, val);

        map->unlock(map->lock_arg);

        return ret;
}
EXPORT_SYMBOL_GPL(regmap_write);

/**
 * regmap_write_async(): Write a value to a single register asynchronously
 *
 * @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_async(struct regmap *map, unsigned int reg, unsigned int val)
{
        int ret;

        if (reg % map->reg_stride)
                return -EINVAL;

        map->lock(map->lock_arg);

        map->async = true;

        ret = _regmap_write(map, reg, val);

        map->async = false;

        map->unlock(map->lock_arg);

        return ret;
}
EXPORT_SYMBOL_GPL(regmap_write_async);

/**
 * 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;

        if (!regmap_can_raw_write(map))
                return -EINVAL;
        if (val_len % map->format.val_bytes)
                return -EINVAL;

        map->lock(map->lock_arg);

        ret = _regmap_raw_write(map, reg, val, val_len);

        map->unlock(map->lock_arg);

        return ret;
}
EXPORT_SYMBOL_GPL(regmap_raw_write);

/**
 * regmap_field_write(): Write a value to a single register field
 *
 * @field: Register field 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_field_write(struct regmap_field *field, unsigned int val)
{
        return regmap_update_bits(field->regmap, field->reg,
                                field->mask, val << field->shift);
}
EXPORT_SYMBOL_GPL(regmap_field_write);

/**
 * regmap_field_update_bits():  Perform a read/modify/write cycle
 *                              on the register field
 *
 * @field: Register field to write to
 * @mask: Bitmask to change
 * @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_field_update_bits(struct regmap_field *field, unsigned int mask, unsigned int val)
{
        mask = (mask << field->shift) & field->mask;

        return regmap_update_bits(field->regmap, field->reg,
                                  mask, val << field->shift);
}
EXPORT_SYMBOL_GPL(regmap_field_update_bits);

/**
 * regmap_fields_write(): Write a value to a single register field with port ID
 *
 * @field: Register field to write to
 * @id: port ID
 * @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_fields_write(struct regmap_field *field, unsigned int id,
                        unsigned int val)
{
        if (id >= field->id_size)
                return -EINVAL;

        return regmap_update_bits(field->regmap,
                                  field->reg + (field->id_offset * id),
                                  field->mask, val << field->shift);
}
EXPORT_SYMBOL_GPL(regmap_fields_write);

/**
 * regmap_fields_update_bits(): Perform a read/modify/write cycle
 *                              on the register field
 *
 * @field: Register field to write to
 * @id: port ID
 * @mask: Bitmask to change
 * @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_fields_update_bits(struct regmap_field *field,  unsigned int id,
                              unsigned int mask, unsigned int val)
{
        if (id >= field->id_size)
                return -EINVAL;

        mask = (mask << field->shift) & field->mask;

        return regmap_update_bits(field->regmap,
                                  field->reg + (field->id_offset * id),
                                  mask, val << field->shift);
}
EXPORT_SYMBOL_GPL(regmap_fields_update_bits);

/*
 * regmap_bulk_write(): Write multiple registers to the device
 *
 * @map: Register map to write to
 * @reg: First register to be write from
 * @val: Block of data to be written, in native register size for device
 * @val_count: Number of registers to write
 *
 * This function is intended to be used for writing a large block of
 * data to the device either in single transfer or multiple transfer.
 *
 * A value of zero will be returned on success, a negative errno will
 * be returned in error cases.
 */
int regmap_bulk_write(struct regmap *map, unsigned int reg, const void *val,
                     size_t val_count)
{
        int ret = 0, i;
        size_t val_bytes = map->format.val_bytes;

        if (map->bus && !map->format.parse_inplace)
                return -EINVAL;
        if (reg % map->reg_stride)
                return -EINVAL;

        /*
         * Some devices don't support bulk write, for
         * them we have a series of single write operations.
         */
        if (!map->bus || map->use_single_rw) {
                map->lock(map->lock_arg);
                for (i = 0; i < val_count; i++) {
                        unsigned int ival;

                        switch (val_bytes) {
                        case 1:
                                ival = *(u8 *)(val + (i * val_bytes));
                                break;
                        case 2:
                                ival = *(u16 *)(val + (i * val_bytes));
                                break;
                        case 4:
                                ival = *(u32 *)(val + (i * val_bytes));
                                break;
#ifdef CONFIG_64BIT
                        case 8:
                                ival = *(u64 *)(val + (i * val_bytes));
                                break;
#endif
                        default:
                                ret = -EINVAL;
                                goto out;
                        }

                        ret = _regmap_write(map, reg + (i * map->reg_stride),
                                        ival);
                        if (ret != 0)
                                goto out;
                }
out:
                map->unlock(map->lock_arg);
        } else {
                void *wval;

                wval = kmemdup(val, val_count * val_bytes, GFP_KERNEL);
                if (!wval) {
                        dev_err(map->dev, "Error in memory allocation\n");
                        return -ENOMEM;
                }
                for (i = 0; i < val_count * val_bytes; i += val_bytes)
                        map->format.parse_inplace(wval + i);

                map->lock(map->lock_arg);
                ret = _regmap_raw_write(map, reg, wval, val_bytes * val_count);
                map->unlock(map->lock_arg);

                kfree(wval);
        }
        return ret;
}
EXPORT_SYMBOL_GPL(regmap_bulk_write);

/*
 * _regmap_raw_multi_reg_write()
 *
 * the (register,newvalue) pairs in regs have not been formatted, but
 * they are all in the same page and have been changed to being page
 * relative. The page register has been written if that was neccessary.
 */
static int _regmap_raw_multi_reg_write(struct regmap *map,
                                       const struct reg_default *regs,
                                       size_t num_regs)
{
        int ret;
        void *buf;
        int i;
        u8 *u8;
        size_t val_bytes = map->format.val_bytes;
        size_t reg_bytes = map->format.reg_bytes;
        size_t pad_bytes = map->format.pad_bytes;
        size_t pair_size = reg_bytes + pad_bytes + val_bytes;
        size_t len = pair_size * num_regs;

        if (!len)
                return -EINVAL;

        buf = kzalloc(len, GFP_KERNEL);
        if (!buf)
                return -ENOMEM;

        /* We have to linearise by hand. */

        u8 = buf;

        for (i = 0; i < num_regs; i++) {
                int reg = regs[i].reg;
                int val = regs[i].def;
                trace_regmap_hw_write_start(map->dev, reg, 1);
                map->format.format_reg(u8, reg, map->reg_shift);
                u8 += reg_bytes + pad_bytes;
                map->format.format_val(u8, val, 0);
                u8 += val_bytes;
        }
        u8 = buf;
        *u8 |= map->write_flag_mask;

        ret = map->bus->write(map->bus_context, buf, len);

        kfree(buf);

        for (i = 0; i < num_regs; i++) {
                int reg = regs[i].reg;
                trace_regmap_hw_write_done(map->dev, reg, 1);
        }
        return ret;
}

static unsigned int _regmap_register_page(struct regmap *map,
                                          unsigned int reg,
                                          struct regmap_range_node *range)
{
        unsigned int win_page = (reg - range->range_min) / range->window_len;

        return win_page;
}

static int _regmap_range_multi_paged_reg_write(struct regmap *map,
                                               struct reg_default *regs,
                                               size_t num_regs)
{
        int ret;
        int i, n;
        struct reg_default *base;
        unsigned int this_page = 0;
        /*
         * the set of registers are not neccessarily in order, but
         * since the order of write must be preserved this algorithm
         * chops the set each time the page changes
         */
        base = regs;
        for (i = 0, n = 0; i < num_regs; i++, n++) {
                unsigned int reg = regs[i].reg;
                struct regmap_range_node *range;

                range = _regmap_range_lookup(map, reg);
                if (range) {
                        unsigned int win_page = _regmap_register_page(map, reg,
                                                                      range);

                        if (i == 0)
                                this_page = win_page;
                        if (win_page != this_page) {
                                this_page = win_page;
                                ret = _regmap_raw_multi_reg_write(map, base, n);
                                if (ret != 0)
                                        return ret;
                                base += n;
                                n = 0;
                        }
                        ret = _regmap_select_page(map, &base[n].reg, range, 1);
                        if (ret != 0)
                                return ret;
                }
        }
        if (n > 0)
                return _regmap_raw_multi_reg_write(map, base, n);
        return 0;
}

static int _regmap_multi_reg_write(struct regmap *map,
                                   const struct reg_default *regs,
                                   size_t num_regs)
{
        int i;
        int ret;

        if (!map->can_multi_write) {
                for (i = 0; i < num_regs; i++) {
                        ret = _regmap_write(map, regs[i].reg, regs[i].def);
                        if (ret != 0)
                                return ret;
                }
                return 0;
        }

        if (!map->format.parse_inplace)
                return -EINVAL;

        if (map->writeable_reg)
                for (i = 0; i < num_regs; i++) {
                        int reg = regs[i].reg;
                        if (!map->writeable_reg(map->dev, reg))
                                return -EINVAL;
                        if (reg % map->reg_stride)
                                return -EINVAL;
                }

        if (!map->cache_bypass) {
                for (i = 0; i < num_regs; i++) {
                        unsigned int val = regs[i].def;
                        unsigned int reg = regs[i].reg;
                        ret = regcache_write(map, reg, val);
                        if (ret) {
                                dev_err(map->dev,
                                "Error in caching of register: %x ret: %d\n",
                                                                reg, ret);
                                return ret;
                        }
                }
                if (map->cache_only) {
                        map->cache_dirty = true;
                        return 0;
                }
        }

        WARN_ON(!map->bus);

        for (i = 0; i < num_regs; i++) {
                unsigned int reg = regs[i].reg;
                struct regmap_range_node *range;
                range = _regmap_range_lookup(map, reg);
                if (range) {
                        size_t len = sizeof(struct reg_default)*num_regs;
                        struct reg_default *base = kmemdup(regs, len,
                                                           GFP_KERNEL);
                        if (!base)
                                return -ENOMEM;
                        ret = _regmap_range_multi_paged_reg_write(map, base,
                                                                  num_regs);
                        kfree(base);

                        return ret;
                }
        }
        return _regmap_raw_multi_reg_write(map, regs, num_regs);
}

/*
 * regmap_multi_reg_write(): Write multiple registers to the device
 *
 * where the set of register,value pairs are supplied in any order,
 * possibly not all in a single range.
 *
 * @map: Register map to write to
 * @regs: Array of structures containing register,value to be written
 * @num_regs: Number of registers to write
 *
 * The 'normal' block write mode will send ultimately send data on the
 * target bus as R,V1,V2,V3,..,Vn where successively higer registers are
 * addressed. However, this alternative block multi write mode will send
 * the data as R1,V1,R2,V2,..,Rn,Vn on the target bus. The target device
 * must of course support the mode.
 *
 * A value of zero will be returned on success, a negative errno will be
 * returned in error cases.
 */
int regmap_multi_reg_write(struct regmap *map, const struct reg_default *regs,
                           int num_regs)
{
        int ret;

        map->lock(map->lock_arg);

        ret = _regmap_multi_reg_write(map, regs, num_regs);

        map->unlock(map->lock_arg);

        return ret;
}
EXPORT_SYMBOL_GPL(regmap_multi_reg_write);

/*
 * regmap_multi_reg_write_bypassed(): Write multiple registers to the
 *                                    device but not the cache
 *
 * where the set of register are supplied in any order
 *
 * @map: Register map to write to
 * @regs: Array of structures containing register,value to be written
 * @num_regs: Number of registers to write
 *
 * This function is intended to be used for writing a large block of data
 * atomically to the device in single transfer for those I2C client devices
 * that implement this alternative block write mode.
 *
 * A value of zero will be returned on success, a negative errno will
 * be returned in error cases.
 */
int regmap_multi_reg_write_bypassed(struct regmap *map,
                                    const struct reg_default *regs,
                                    int num_regs)
{
        int ret;
        bool bypass;

        map->lock(map->lock_arg);

        bypass = map->cache_bypass;
        map->cache_bypass = true;

        ret = _regmap_multi_reg_write(map, regs, num_regs);

        map->cache_bypass = bypass;

        map->unlock(map->lock_arg);

        return ret;
}
EXPORT_SYMBOL_GPL(regmap_multi_reg_write_bypassed);

/**
 * regmap_raw_write_async(): Write raw values to one or more registers
 *                           asynchronously
 *
 * @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.  Must be valid until regmap_async_complete() is called.
 * @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.
 *
 * If supported by the underlying bus the write will be scheduled
 * asynchronously, helping maximise I/O speed on higher speed buses
 * like SPI.  regmap_async_complete() can be called to ensure that all
 * asynchrnous writes have been completed.
 *
 * A value of zero will be returned on success, a negative errno will
 * be returned in error cases.
 */
int regmap_raw_write_async(struct regmap *map, unsigned int reg,
                           const void *val, size_t val_len)
{
        int ret;

        if (val_len % map->format.val_bytes)
                return -EINVAL;
        if (reg % map->reg_stride)
                return -EINVAL;

        map->lock(map->lock_arg);

        map->async = true;

        ret = _regmap_raw_write(map, reg, val, val_len);

        map->async = false;

        map->unlock(map->lock_arg);

        return ret;
}
EXPORT_SYMBOL_GPL(regmap_raw_write_async);

static int _regmap_raw_read(struct regmap *map, unsigned int reg, void *val,
                            unsigned int val_len)
{
        struct regmap_range_node *range;
        u8 *u8 = map->work_buf;
        int ret;

        WARN_ON(!map->bus);

        range = _regmap_range_lookup(map, reg);
        if (range) {
                ret = _regmap_select_page(map, &reg, range,
                                          val_len / map->format.val_bytes);
                if (ret != 0)
                        return ret;
        }

        map->format.format_reg(map->work_buf, reg, map->reg_shift);

        /*
         * Some buses or devices 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.
         */
        u8[0] |= map->read_flag_mask;

        trace_regmap_hw_read_start(map->dev, reg,
                                   val_len / map->format.val_bytes);

        ret = map->bus->read(map->bus_context, map->work_buf,
                             map->format.reg_bytes + map->format.pad_bytes,
                             val, val_len);

        trace_regmap_hw_read_done(map->dev, reg,
                                  val_len / map->format.val_bytes);

        return ret;
}

static int _regmap_bus_reg_read(void *context, unsigned int reg,
                                unsigned int *val)
{
        struct regmap *map = context;

        return map->bus->reg_read(map->bus_context, reg, val);
}

static int _regmap_bus_read(void *context, unsigned int reg,
                            unsigned int *val)
{
        int ret;
        struct regmap *map = context;

        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;
}

static int _regmap_read(struct regmap *map, unsigned int reg,
                        unsigned int *val)
{
        int ret;
        void *context = _regmap_map_get_context(map);

        WARN_ON(!map->reg_read);

        if (!map->cache_bypass) {
                ret = regcache_read(map, reg, val);
                if (ret == 0)
                        return 0;
        }

        if (map->cache_only)
                return -EBUSY;

        if (!regmap_readable(map, reg))
                return -EIO;

        ret = map->reg_read(context, reg, val);
        if (ret == 0) {
#ifdef LOG_DEVICE
                if (map->dev && strcmp(dev_name(map->dev), LOG_DEVICE) == 0)
                        dev_info(map->dev, "%x => %x\n", reg, *val);
#endif

                trace_regmap_reg_read(map->dev, reg, *val);

                if (!map->cache_bypass)
                        regcache_write(map, reg, *val);
        }

        return ret;
}

/**
 * regmap_read(): Read a value from a single register
 *
 * @map: Register map to read from
 * @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;

        if (reg % map->reg_stride)
                return -EINVAL;

        map->lock(map->lock_arg);

        ret = _regmap_read(map, reg, val);

        map->unlock(map->lock_arg);

        return ret;
}
EXPORT_SYMBOL_GPL(regmap_read);

/**
 * regmap_raw_read(): Read raw data from the device
 *
 * @map: Register map to read from
 * @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)
{
        size_t val_bytes = map->format.val_bytes;
        size_t val_count = val_len / val_bytes;
        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)
                return -EINVAL;

        map->lock(map->lock_arg);

        if (regmap_volatile_range(map, reg, val_count) || map->cache_bypass ||
            map->cache_type == REGCACHE_NONE) {
                /* Physical block read if there's no cache involved */
                ret = _regmap_raw_read(map, reg, val, val_len);

        } else {
                /* Otherwise go word by word for the cache; should be low
                 * cost as we expect to hit the cache.
                 */
                for (i = 0; i < val_count; i++) {
                        ret = _regmap_read(map, reg + (i * map->reg_stride),
                                           &v);
                        if (ret != 0)
                                goto out;

                        map->format.format_val(val + (i * val_bytes), v, 0);
                }
        }

 out:
        map->unlock(map->lock_arg);

        return ret;
}
EXPORT_SYMBOL_GPL(regmap_raw_read);

/**
 * regmap_field_read(): Read a value to a single register field
 *
 * @field: Register field to 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_field_read(struct regmap_field *field, unsigned int *val)
{
        int ret;
        unsigned int reg_val;
        ret = regmap_read(field->regmap, field->reg, &reg_val);
        if (ret != 0)
                return ret;

        reg_val &= field->mask;
        reg_val >>= field->shift;
        *val = reg_val;

        return ret;
}
EXPORT_SYMBOL_GPL(regmap_field_read);

/**
 * regmap_fields_read(): Read a value to a single register field with port ID
 *
 * @field: Register field to read from
 * @id: port ID
 * @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_fields_read(struct regmap_field *field, unsigned int id,
                       unsigned int *val)
{
        int ret;
        unsigned int reg_val;

        if (id >= field->id_size)
                return -EINVAL;

        ret = regmap_read(field->regmap,
                          field->reg + (field->id_offset * id),
                          &reg_val);
        if (ret != 0)
                return ret;

        reg_val &= field->mask;
        reg_val >>= field->shift;
        *val = reg_val;

        return ret;
}
EXPORT_SYMBOL_GPL(regmap_fields_read);

/**
 * regmap_bulk_read(): Read multiple registers from the device
 *
 * @map: Register map to read from
 * @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;
        bool vol = regmap_volatile_range(map, reg, val_count);

        if (reg % map->reg_stride)
                return -EINVAL;

        if (map->bus && map->format.parse_inplace && (vol || map->cache_type == REGCACHE_NONE)) {
                /*
                 * Some devices does not support bulk read, for
                 * them we have a series of single read operations.
                 */
                if (map->use_single_rw) {
                        for (i = 0; i < val_count; i++) {
                                ret = regmap_raw_read(map,
                                                reg + (i * map->reg_stride),
                                                val + (i * val_bytes),
                                                val_bytes);
                                if (ret != 0)
                                        return ret;
                        }
                } else {
                        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_inplace(val + i);
        } else {
                for (i = 0; i < val_count; i++) {
                        unsigned int ival;
                        ret = regmap_read(map, reg + (i * map->reg_stride),
                                          &ival);
                        if (ret != 0)
                                return ret;
                        memcpy(val + (i * val_bytes), &ival, val_bytes);
                }
        }

        return 0;
}
EXPORT_SYMBOL_GPL(regmap_bulk_read);

static int _regmap_update_bits(struct regmap *map, unsigned int reg,
                               unsigned int mask, unsigned int val,
                               bool *change)
{
        int ret;
        unsigned int tmp, orig;

        ret = _regmap_read(map, reg, &orig);
        if (ret != 0)
                return ret;

        tmp = orig & ~mask;
        tmp |= val & mask;

        if (tmp != orig) {
                ret = _regmap_write(map, reg, tmp);
                if (change)
                        *change = true;
        } else {
                if (change)
                        *change = false;
        }

        return ret;
}

/**
 * regmap_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;

        map->lock(map->lock_arg);
        ret = _regmap_update_bits(map, reg, mask, val, NULL);
        map->unlock(map->lock_arg);

        return ret;
}
EXPORT_SYMBOL_GPL(regmap_update_bits);

/**
 * regmap_update_bits_async: Perform a read/modify/write cycle on the register
 *                           map asynchronously
 *
 * @map: Register map to update
 * @reg: Register to update
 * @mask: Bitmask to change
 * @val: New value for bitmask
 *
 * With most buses the read must be done synchronously so this is most
 * useful for devices with a cache which do not need to interact with
 * the hardware to determine the current register value.
 *
 * Returns zero for success, a negative number on error.
 */
int regmap_update_bits_async(struct regmap *map, unsigned int reg,
                             unsigned int mask, unsigned int val)
{
        int ret;

        map->lock(map->lock_arg);

        map->async = true;

        ret = _regmap_update_bits(map, reg, mask, val, NULL);

        map->async = false;

        map->unlock(map->lock_arg);

        return ret;
}
EXPORT_SYMBOL_GPL(regmap_update_bits_async);

/**
 * regmap_update_bits_check: Perform a read/modify/write cycle on the
 *                           register map and report if updated
 *
 * @map: Register map to update
 * @reg: Register to update
 * @mask: Bitmask to change
 * @val: New value for bitmask
 * @change: Boolean indicating if a write was done
 *
 * Returns zero for success, a negative number on error.
 */
int regmap_update_bits_check(struct regmap *map, unsigned int reg,
                             unsigned int mask, unsigned int val,
                             bool *change)
{
        int ret;

        map->lock(map->lock_arg);
        ret = _regmap_update_bits(map, reg, mask, val, change);
        map->unlock(map->lock_arg);
        return ret;
}
EXPORT_SYMBOL_GPL(regmap_update_bits_check);

/**
 * regmap_update_bits_check_async: Perform a read/modify/write cycle on the
 *                                 register map asynchronously and report if
 *                                 updated
 *
 * @map: Register map to update
 * @reg: Register to update
 * @mask: Bitmask to change
 * @val: New value for bitmask
 * @change: Boolean indicating if a write was done
 *
 * With most buses the read must be done synchronously so this is most
 * useful for devices with a cache which do not need to interact with
 * the hardware to determine the current register value.
 *
 * Returns zero for success, a negative number on error.
 */
int regmap_update_bits_check_async(struct regmap *map, unsigned int reg,
                                   unsigned int mask, unsigned int val,
                                   bool *change)
{
        int ret;

        map->lock(map->lock_arg);

        map->async = true;

        ret = _regmap_update_bits(map, reg, mask, val, change);

        map->async = false;

        map->unlock(map->lock_arg);

        return ret;
}
EXPORT_SYMBOL_GPL(regmap_update_bits_check_async);

void regmap_async_complete_cb(struct regmap_async *async, int ret)
{
        struct regmap *map = async->map;
        bool wake;

        trace_regmap_async_io_complete(map->dev);

        spin_lock(&map->async_lock);
        list_move(&async->list, &map->async_free);
        wake = list_empty(&map->async_list);

        if (ret != 0)
                map->async_ret = ret;

        spin_unlock(&map->async_lock);

        if (wake)
                wake_up(&map->async_waitq);
}
EXPORT_SYMBOL_GPL(regmap_async_complete_cb);

static int regmap_async_is_done(struct regmap *map)
{
        unsigned long flags;
        int ret;

        spin_lock_irqsave(&map->async_lock, flags);
        ret = list_empty(&map->async_list);
        spin_unlock_irqrestore(&map->async_lock, flags);

        return ret;
}

/**
 * regmap_async_complete: Ensure all asynchronous I/O has completed.
 *
 * @map: Map to operate on.
 *
 * Blocks until any pending asynchronous I/O has completed.  Returns
 * an error code for any failed I/O operations.
 */
int regmap_async_complete(struct regmap *map)
{
        unsigned long flags;
        int ret;

        /* Nothing to do with no async support */
        if (!map->bus || !map->bus->async_write)
                return 0;

        trace_regmap_async_complete_start(map->dev);

        wait_event(map->async_waitq, regmap_async_is_done(map));

        spin_lock_irqsave(&map->async_lock, flags);
        ret = map->async_ret;
        map->async_ret = 0;
        spin_unlock_irqrestore(&map->async_lock, flags);

        trace_regmap_async_complete_done(map->dev);

        return ret;
}
EXPORT_SYMBOL_GPL(regmap_async_complete);

/**
 * regmap_register_patch: Register and apply register updates to be applied
 *                        on device initialistion
 *
 * @map: Register map to apply updates to.
 * @regs: Values to update.
 * @num_regs: Number of entries in regs.
 *
 * Register a set of register updates to be applied to the device
 * whenever the device registers are synchronised with the cache and
 * apply them immediately.  Typically this is used to apply
 * corrections to be applied to the device defaults on startup, such
 * as the updates some vendors provide to undocumented registers.
 *
 * The caller must ensure that this function cannot be called
 * concurrently with either itself or regcache_sync().
 */
int regmap_register_patch(struct regmap *map, const struct reg_default *regs,
                          int num_regs)
{
        struct reg_default *p;
        int ret;
        bool bypass;

        if (WARN_ONCE(num_regs <= 0, "invalid registers number (%d)\n",
            num_regs))
                return 0;

        p = krealloc(map->patch,
                     sizeof(struct reg_default) * (map->patch_regs + num_regs),
                     GFP_KERNEL);
        if (p) {
                memcpy(p + map->patch_regs, regs, num_regs * sizeof(*regs));
                map->patch = p;
                map->patch_regs += num_regs;
        } else {
                return -ENOMEM;
        }

        map->lock(map->lock_arg);

        bypass = map->cache_bypass;

        map->cache_bypass = true;
        map->async = true;

        ret = _regmap_multi_reg_write(map, regs, num_regs);
        if (ret != 0)
                goto out;

out:
        map->async = false;
        map->cache_bypass = bypass;

        map->unlock(map->lock_arg);

        regmap_async_complete(map);

        return ret;
}
EXPORT_SYMBOL_GPL(regmap_register_patch);

/*
 * regmap_get_val_bytes(): Report the size of a register value
 *
 * Report the size of a register value, mainly intended to for use by
 * generic infrastructure built on top of regmap.
 */
int regmap_get_val_bytes(struct regmap *map)
{
        if (map->format.format_write)
                return -EINVAL;

        return map->format.val_bytes;
}
EXPORT_SYMBOL_GPL(regmap_get_val_bytes);

int regmap_parse_val(struct regmap *map, const void *buf,
                        unsigned int *val)
{
        if (!map->format.parse_val)
                return -EINVAL;

        *val = map->format.parse_val(buf);

        return 0;
}
EXPORT_SYMBOL_GPL(regmap_parse_val);

static int __init regmap_initcall(void)
{
        regmap_debugfs_initcall();

        return 0;
}
postcore_initcall(regmap_initcall);