source: GPL/trunk/lib32/regcache-flat.c@ 709

// SPDX-License-Identifier: GPL-2.0
//
// Register cache access API - flat caching support
//
// Copyright 2012 Wolfson Microelectronics plc
//
// Author: Mark Brown <broonie@opensource.wolfsonmicro.com>

/* from 5.10.10 */

#include <linux/device.h>
#include <linux/seq_file.h>
#include <linux/slab.h>

#include "internal.h"

static inline unsigned int regcache_flat_get_index(const struct regmap *map,
                                                   unsigned int reg)
{
        return regcache_get_index_by_order(map, reg);
}

static int regcache_flat_init(struct regmap *map)
{
        int i;
        unsigned int *cache;

        if (!map || map->reg_stride_order < 0 || !map->max_register)
                return -EINVAL;

        map->cache = kcalloc(regcache_flat_get_index(map, map->max_register)
                             + 1, sizeof(unsigned int), GFP_KERNEL);
        if (!map->cache)
                return -ENOMEM;

        cache = map->cache;

        for (i = 0; i < map->num_reg_defaults; i++) {
                unsigned int reg = map->reg_defaults[i].reg;
                unsigned int index = regcache_flat_get_index(map, reg);

                cache[index] = map->reg_defaults[i].def;
        }

        return 0;
}

static int regcache_flat_exit(struct regmap *map)
{
        kfree(map->cache);
        map->cache = NULL;

        return 0;
}

static int regcache_flat_read(struct regmap *map,
                              unsigned int reg, unsigned int *value)
{
        unsigned int *cache = map->cache;
        unsigned int index = regcache_flat_get_index(map, reg);

        *value = cache[index];

        return 0;
}

static int regcache_flat_write(struct regmap *map, unsigned int reg,
                               unsigned int value)
{
        unsigned int *cache = map->cache;
        unsigned int index = regcache_flat_get_index(map, reg);

        cache[index] = value;

        return 0;
}

struct regcache_ops regcache_flat_ops = {
        .type = REGCACHE_FLAT,
        .name = "flat",
        .init = regcache_flat_init,
        .exit = regcache_flat_exit,
        .read = regcache_flat_read,
        .write = regcache_flat_write,
};