regmap.c

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/*
 * Register map access API
 *
 * Copyright 2011 Wolfson Microelectronics plc
 *
 * Author: Mark Brown <[email protected]>
 *
 * 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>

#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);

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);

    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);

    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);

    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);

    return false;
}

static bool regmap_volatile_range(struct regmap *map, unsigned int reg,
    unsigned int 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_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_native(void *buf, unsigned int val,
                    unsigned int shift)
{
    *(u32 *)buf = val << shift;
}

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

    return b[0];
}

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

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

    return b[0];
}

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

static unsigned int regmap_parse_24(void *buf)
{
    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(void *buf)
{
    __be32 *b = buf;

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

    return b[0];
}

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

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

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

static void regmap_lock_spinlock(struct regmap *map)
{
    spin_lock(&map->spinlock);
}

static void regmap_unlock_spinlock(struct regmap *map)
{
    spin_unlock(&map->spinlock);
}

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);
}

struct regmap *regmap_init(struct device *dev,
               const struct regmap_bus *bus,
               void *bus_context,
               const struct regmap_config *config)
{
    struct regmap *map, **m;
    int ret = -EINVAL;
    enum regmap_endian reg_endian, val_endian;
    int i, j;

    if (!bus || !config)
        goto err;

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

    if (bus->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->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->dev = dev;
    map->bus = bus;
    map->bus_context = bus_context;
    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;
    map->name = config->name;

    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 {
        map->read_flag_mask = bus->read_flag_mask;
    }

    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 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;
    }

    switch (config->val_bits) {
    case 8:
        map->format.format_val = regmap_format_8;
        map->format.parse_val = regmap_parse_8;
        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;
            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;
            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;
    }

    map->range_tree = RB_ROOT;
    for (i = 0; i < config->n_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 ||
            range_cfg->range_max > map->max_register ||
            range_cfg->selector_reg > map->max_register ||
            range_cfg->window_len == 0)
            goto err_range;

        /* Make sure, that this register range has no selector
           or data window within its boundary */
        for (j = 0; j < config->n_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;

            if (range_cfg->range_min <= sel_reg &&
                sel_reg <= range_cfg->range_max) {
                goto err_range;
            }

            if (!(win_max < range_cfg->range_min ||
                  win_min > range_cfg->range_max)) {
                goto err_range;
            }
        }

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

        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) == false) {
            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;

    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) {
        ret = -ENOMEM;
        goto err_debugfs;
    }
    *m = map;
    devres_add(dev, m);

    return map;

err_debugfs:
    regmap_debugfs_exit(map);
    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);
}

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);

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);

void regmap_exit(struct regmap *map)
{
    regcache_exit(map);
    regmap_debugfs_exit(map);
    regmap_range_exit(map);
    if (map->bus->free_context)
        map->bus->free_context(map->bus_context);
    kfree(map->work_buf);
    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;
}

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);

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

    range = _regmap_range_lookup(map, *reg);
    if (range) {
        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;
}

static int _regmap_raw_write(struct regmap *map, unsigned int reg,
                 const void *val, size_t val_len)
{
    u8 *u8 = map->work_buf;
    void *buf;
    int ret = -ENOTSUPP;
    size_t len;
    int i;

    /* 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++) {
            memcpy(map->work_buf, val + (i * val_bytes), val_bytes);
            ival = map->format.parse_val(map->work_buf);
            ret = regcache_write(map, reg + (i * map->reg_stride),
                         ival);
            if (ret) {
                dev_err(map->dev,
                   "Error in caching of register: %u ret: %d\n",
                    reg + i, ret);
                return ret;
            }
        }
        if (map->cache_only) {
            map->cache_dirty = true;
            return 0;
        }
    }

    ret = _regmap_select_page(map, &reg, val_len / map->format.val_bytes);
    if (ret < 0)
        return ret;

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

    u8[0] |= map->write_flag_mask;

    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 == (map->work_buf + map->format.pad_bytes +
            map->format.reg_bytes))
        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;
}

int _regmap_write(struct regmap *map, unsigned int reg,
          unsigned int val)
{
    int ret;
    BUG_ON(!map->format.format_write && !map->format.format_val);

    if (!map->cache_bypass && map->format.format_write) {
        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 (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);

    if (map->format.format_write) {
        ret = _regmap_select_page(map, &reg, 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;
    } else {
        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);
    }
}

int regmap_write(struct regmap *map, unsigned int reg, unsigned int val)
{
    int ret;

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

    map->lock(map);

    ret = _regmap_write(map, reg, val);

    map->unlock(map);

    return ret;
}
EXPORT_SYMBOL_GPL(regmap_write);

int regmap_raw_write(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);

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

    map->unlock(map);

    return ret;
}
EXPORT_SYMBOL_GPL(regmap_raw_write);

/*
 * 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 be 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;
    void *wval;

    if (!map->format.parse_val)
        return -EINVAL;
    if (reg % map->reg_stride)
        return -EINVAL;

    map->lock(map);

    /* No formatting is require if val_byte is 1 */
    if (val_bytes == 1) {
        wval = (void *)val;
    } else {
        wval = kmemdup(val, val_count * val_bytes, GFP_KERNEL);
        if (!wval) {
            ret = -ENOMEM;
            dev_err(map->dev, "Error in memory allocation\n");
            goto out;
        }
        for (i = 0; i < val_count * val_bytes; i += val_bytes)
            map->format.parse_val(wval + i);
    }
    /*
     * Some devices does not support bulk write, for
     * them we have a series of single write operations.
     */
    if (map->use_single_rw) {
        for (i = 0; i < val_count; i++) {
            ret = regmap_raw_write(map,
                        reg + (i * map->reg_stride),
                        val + (i * val_bytes),
                        val_bytes);
            if (ret != 0)
                return ret;
        }
    } else {
        ret = _regmap_raw_write(map, reg, wval, val_bytes * val_count);
    }

    if (val_bytes != 1)
        kfree(wval);

out:
    map->unlock(map);
    return ret;
}
EXPORT_SYMBOL_GPL(regmap_bulk_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;

    ret = _regmap_select_page(map, &reg, 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_read(struct regmap *map, unsigned int reg,
            unsigned int *val)
{
    int ret;

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

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

    if (map->cache_only)
        return -EBUSY;

    ret = _regmap_raw_read(map, reg, map->work_buf, map->format.val_bytes);
    if (ret == 0) {
        *val = map->format.parse_val(map->work_buf);

#ifdef LOG_DEVICE
        if (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 (ret == 0 && !map->cache_bypass)
        regcache_write(map, reg, *val);

    return ret;
}

int regmap_read(struct regmap *map, unsigned int reg, unsigned int *val)
{
    int ret;

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

    map->lock(map);

    ret = _regmap_read(map, reg, val);

    map->unlock(map);

    return ret;
}
EXPORT_SYMBOL_GPL(regmap_read);

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

    map->lock(map);

    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);

    return ret;
}
EXPORT_SYMBOL_GPL(regmap_raw_read);

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 (!map->format.parse_val)
        return -EINVAL;
    if (reg % map->reg_stride)
        return -EINVAL;

    if (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_val(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);
        *change = true;
    } else {
        *change = false;
    }

    return ret;
}

int regmap_update_bits(struct regmap *map, unsigned int reg,
               unsigned int mask, unsigned int val)
{
    bool change;
    int ret;

    map->lock(map);
    ret = _regmap_update_bits(map, reg, mask, val, &change);
    map->unlock(map);

    return ret;
}
EXPORT_SYMBOL_GPL(regmap_update_bits);

int regmap_update_bits_check(struct regmap *map, unsigned int reg,
                 unsigned int mask, unsigned int val,
                 bool *change)
{
    int ret;

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

int regmap_register_patch(struct regmap *map, const struct reg_default *regs,
              int num_regs)
{
    int i, ret;
    bool bypass;

    /* If needed the implementation can be extended to support this */
    if (map->patch)
        return -EBUSY;

    map->lock(map);

    bypass = map->cache_bypass;

    map->cache_bypass = true;

    /* Write out first; it's useful to apply even if we fail later. */
    for (i = 0; i < num_regs; i++) {
        ret = _regmap_write(map, regs[i].reg, regs[i].def);
        if (ret != 0) {
            dev_err(map->dev, "Failed to write %x = %x: %d\n",
                regs[i].reg, regs[i].def, ret);
            goto out;
        }
    }

    map->patch = kcalloc(num_regs, sizeof(struct reg_default), GFP_KERNEL);
    if (map->patch != NULL) {
        memcpy(map->patch, regs,
               num_regs * sizeof(struct reg_default));
        map->patch_regs = num_regs;
    } else {
        ret = -ENOMEM;
    }

out:
    map->cache_bypass = bypass;

    map->unlock(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);

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

    return 0;
}
postcore_initcall(regmap_initcall);