kernel/drivers/mfd/wm8400-core.c

   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
  26 static 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  */
  46 u16 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 }
  57 EXPORT_SYMBOL_GPL(wm8400_reg_read);
  58
  59 int wm8400_block_read(struct wm8400 *wm8400, u8 reg, int count, u16 *data)
  60 {
  61         return regmap_bulk_read(wm8400->regmap, reg, data, count);
  62 }
  63 EXPORT_SYMBOL_GPL(wm8400_block_read);
  64
  65 static int wm8400_register_codec(struct wm8400 *wm8400)
  66 {
  67         const 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  */
  83 static 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
 129 err_children:
 130         mfd_remove_devices(wm8400->dev);
 131         return ret;
 132 }
 133
 134 static void wm8400_release(struct wm8400 *wm8400)
 135 {
 136         mfd_remove_devices(wm8400->dev);
 137 }
 138
 139 static 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  */
 153 void wm8400_reset_codec_reg_cache(struct wm8400 *wm8400)
 154 {
 155         regmap_reinit_cache(wm8400->regmap, &wm8400_regmap_config);
 156 }
 157 EXPORT_SYMBOL_GPL(wm8400_reset_codec_reg_cache);
 158
 159 #if defined(CONFIG_I2C) || defined(CONFIG_I2C_MODULE)
 160 static int wm8400_i2c_probe(struct i2c_client *i2c,
 161                             const struct i2c_device_id *id)
 162 {
 163         struct wm8400 *wm8400;
 164
 165         wm8400 = devm_kzalloc(&i2c->dev, sizeof(struct wm8400), GFP_KERNEL);
 166         if (!wm8400)
 167                 return -ENOMEM;
 168
 169         wm8400->regmap = devm_regmap_init_i2c(i2c, &wm8400_regmap_config);
 170         if (IS_ERR(wm8400->regmap))
 171                 return PTR_ERR(wm8400->regmap);
 172
 173         wm8400->dev = &i2c->dev;
 174         i2c_set_clientdata(i2c, wm8400);
 175
 176         return wm8400_init(wm8400, dev_get_platdata(&i2c->dev));
 177 }
 178
 179 static int wm8400_i2c_remove(struct i2c_client *i2c)
 180 {
 181         struct wm8400 *wm8400 = i2c_get_clientdata(i2c);
 182
 183         wm8400_release(wm8400);
 184
 185         return 0;
 186 }
 187
 188 static const struct i2c_device_id wm8400_i2c_id[] = {
 189        { "wm8400", 0 },
 190        { }
 191 };
 192 MODULE_DEVICE_TABLE(i2c, wm8400_i2c_id);
 193
 194 static struct i2c_driver wm8400_i2c_driver = {
 195         .driver = {
 196                 .name = "WM8400",
 197                 .owner = THIS_MODULE,
 198         },
 199         .probe    = wm8400_i2c_probe,
 200         .remove   = wm8400_i2c_remove,
 201         .id_table = wm8400_i2c_id,
 202 };
 203 #endif
 204
 205 static int __init wm8400_module_init(void)
 206 {
 207         int ret = -ENODEV;
 208
 209 #if defined(CONFIG_I2C) || defined(CONFIG_I2C_MODULE)
 210         ret = i2c_add_driver(&wm8400_i2c_driver);
 211         if (ret != 0)
 212                 pr_err("Failed to register I2C driver: %d\n", ret);
 213 #endif
 214
 215         return ret;
 216 }
 217 subsys_initcall(wm8400_module_init);
 218
 219 static void __exit wm8400_module_exit(void)
 220 {
 221 #if defined(CONFIG_I2C) || defined(CONFIG_I2C_MODULE)
 222         i2c_del_driver(&wm8400_i2c_driver);
 223 #endif
 224 }
 225 module_exit(wm8400_module_exit);
 226
 227 MODULE_LICENSE("GPL");
 228 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");