linux/drivers/mfd/wm8400-core.c
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   1/*
   2 * Core driver for WM8400.
   3 *
   4 * Copyright 2008 Wolfson Microelectronics PLC.
   5 *
   6 * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
   7 *
   8 * This program is free software; you can redistribute it and/or
   9 * modify it under the terms of the GNU General Public License as
  10 * published by the Free Software Foundation; either version 2 of the
  11 * License, or (at your option) any later version.
  12 *
  13 */
  14
  15#include <linux/module.h>
  16#include <linux/bug.h>
  17#include <linux/err.h>
  18#include <linux/i2c.h>
  19#include <linux/kernel.h>
  20#include <linux/mfd/core.h>
  21#include <linux/mfd/wm8400-private.h>
  22#include <linux/mfd/wm8400-audio.h>
  23#include <linux/regmap.h>
  24#include <linux/slab.h>
  25
  26static bool wm8400_volatile(struct device *dev, unsigned int reg)
  27{
  28        switch (reg) {
  29        case WM8400_INTERRUPT_STATUS_1:
  30        case WM8400_INTERRUPT_LEVELS:
  31        case WM8400_SHUTDOWN_REASON:
  32                return true;
  33        default:
  34                return false;
  35        }
  36}
  37
  38/**
  39 * wm8400_reg_read - Single register read
  40 *
  41 * @wm8400: Pointer to wm8400 control structure
  42 * @reg:    Register to read
  43 *
  44 * @return  Read value
  45 */
  46u16 wm8400_reg_read(struct wm8400 *wm8400, u8 reg)
  47{
  48        unsigned int val;
  49        int ret;
  50
  51        ret = regmap_read(wm8400->regmap, reg, &val);
  52        if (ret < 0)
  53                return ret;
  54
  55        return val;
  56}
  57EXPORT_SYMBOL_GPL(wm8400_reg_read);
  58
  59int wm8400_block_read(struct wm8400 *wm8400, u8 reg, int count, u16 *data)
  60{
  61        return regmap_bulk_read(wm8400->regmap, reg, data, count);
  62}
  63EXPORT_SYMBOL_GPL(wm8400_block_read);
  64
  65static int wm8400_register_codec(struct wm8400 *wm8400)
  66{
  67        struct mfd_cell cell = {
  68                .name = "wm8400-codec",
  69                .platform_data = wm8400,
  70                .pdata_size = sizeof(*wm8400),
  71        };
  72
  73        return mfd_add_devices(wm8400->dev, -1, &cell, 1, NULL, 0, NULL);
  74}
  75
  76/*
  77 * wm8400_init - Generic initialisation
  78 *
  79 * The WM8400 can be configured as either an I2C or SPI device.  Probe
  80 * functions for each bus set up the accessors then call into this to
  81 * set up the device itself.
  82 */
  83static int wm8400_init(struct wm8400 *wm8400,
  84                       struct wm8400_platform_data *pdata)
  85{
  86        unsigned int reg;
  87        int ret;
  88
  89        dev_set_drvdata(wm8400->dev, wm8400);
  90
  91        /* Check that this is actually a WM8400 */
  92        ret = regmap_read(wm8400->regmap, WM8400_RESET_ID, &reg);
  93        if (ret != 0) {
  94                dev_err(wm8400->dev, "Chip ID register read failed\n");
  95                return -EIO;
  96        }
  97        if (reg != 0x6172) {
  98                dev_err(wm8400->dev, "Device is not a WM8400, ID is %x\n",
  99                        reg);
 100                return -ENODEV;
 101        }
 102
 103        ret = regmap_read(wm8400->regmap, WM8400_ID, &reg);
 104        if (ret != 0) {
 105                dev_err(wm8400->dev, "ID register read failed: %d\n", ret);
 106                return ret;
 107        }
 108        reg = (reg & WM8400_CHIP_REV_MASK) >> WM8400_CHIP_REV_SHIFT;
 109        dev_info(wm8400->dev, "WM8400 revision %x\n", reg);
 110
 111        ret = wm8400_register_codec(wm8400);
 112        if (ret != 0) {
 113                dev_err(wm8400->dev, "Failed to register codec\n");
 114                goto err_children;
 115        }
 116
 117        if (pdata && pdata->platform_init) {
 118                ret = pdata->platform_init(wm8400->dev);
 119                if (ret != 0) {
 120                        dev_err(wm8400->dev, "Platform init failed: %d\n",
 121                                ret);
 122                        goto err_children;
 123                }
 124        } else
 125                dev_warn(wm8400->dev, "No platform initialisation supplied\n");
 126
 127        return 0;
 128
 129err_children:
 130        mfd_remove_devices(wm8400->dev);
 131        return ret;
 132}
 133
 134static void wm8400_release(struct wm8400 *wm8400)
 135{
 136        mfd_remove_devices(wm8400->dev);
 137}
 138
 139static const struct regmap_config wm8400_regmap_config = {
 140        .reg_bits = 8,
 141        .val_bits = 16,
 142        .max_register = WM8400_REGISTER_COUNT - 1,
 143
 144        .volatile_reg = wm8400_volatile,
 145
 146        .cache_type = REGCACHE_RBTREE,
 147};
 148
 149/**
 150 * wm8400_reset_codec_reg_cache - Reset cached codec registers to
 151 * their default values.
 152 */
 153void wm8400_reset_codec_reg_cache(struct wm8400 *wm8400)
 154{
 155        regmap_reinit_cache(wm8400->regmap, &wm8400_regmap_config);
 156}
 157EXPORT_SYMBOL_GPL(wm8400_reset_codec_reg_cache);
 158
 159#if defined(CONFIG_I2C) || defined(CONFIG_I2C_MODULE)
 160static int wm8400_i2c_probe(struct i2c_client *i2c,
 161                            const struct i2c_device_id *id)
 162{
 163        struct wm8400 *wm8400;
 164        int ret;
 165
 166        wm8400 = devm_kzalloc(&i2c->dev, sizeof(struct wm8400), GFP_KERNEL);
 167        if (wm8400 == NULL) {
 168                ret = -ENOMEM;
 169                goto err;
 170        }
 171
 172        wm8400->regmap = devm_regmap_init_i2c(i2c, &wm8400_regmap_config);
 173        if (IS_ERR(wm8400->regmap)) {
 174                ret = PTR_ERR(wm8400->regmap);
 175                goto err;
 176        }
 177
 178        wm8400->dev = &i2c->dev;
 179        i2c_set_clientdata(i2c, wm8400);
 180
 181        ret = wm8400_init(wm8400, dev_get_platdata(&i2c->dev));
 182        if (ret != 0)
 183                goto err;
 184
 185        return 0;
 186
 187err:
 188        return ret;
 189}
 190
 191static int wm8400_i2c_remove(struct i2c_client *i2c)
 192{
 193        struct wm8400 *wm8400 = i2c_get_clientdata(i2c);
 194
 195        wm8400_release(wm8400);
 196
 197        return 0;
 198}
 199
 200static const struct i2c_device_id wm8400_i2c_id[] = {
 201       { "wm8400", 0 },
 202       { }
 203};
 204MODULE_DEVICE_TABLE(i2c, wm8400_i2c_id);
 205
 206static struct i2c_driver wm8400_i2c_driver = {
 207        .driver = {
 208                .name = "WM8400",
 209                .owner = THIS_MODULE,
 210        },
 211        .probe    = wm8400_i2c_probe,
 212        .remove   = wm8400_i2c_remove,
 213        .id_table = wm8400_i2c_id,
 214};
 215#endif
 216
 217static int __init wm8400_module_init(void)
 218{
 219        int ret = -ENODEV;
 220
 221#if defined(CONFIG_I2C) || defined(CONFIG_I2C_MODULE)
 222        ret = i2c_add_driver(&wm8400_i2c_driver);
 223        if (ret != 0)
 224                pr_err("Failed to register I2C driver: %d\n", ret);
 225#endif
 226
 227        return ret;
 228}
 229subsys_initcall(wm8400_module_init);
 230
 231static void __exit wm8400_module_exit(void)
 232{
 233#if defined(CONFIG_I2C) || defined(CONFIG_I2C_MODULE)
 234        i2c_del_driver(&wm8400_i2c_driver);
 235#endif
 236}
 237module_exit(wm8400_module_exit);
 238
 239MODULE_LICENSE("GPL");
 240MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
 241
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