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/init.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 static int wm8400_register_codec(struct wm8400 *wm8400)
  39 {
  40         const struct mfd_cell cell = {
  41                 .name = "wm8400-codec",
  42                 .platform_data = wm8400,
  43                 .pdata_size = sizeof(*wm8400),
  44         };
  45
  46         return devm_mfd_add_devices(wm8400->dev, -1, &cell, 1, NULL, 0, NULL);
  47 }
  48
  49 /*
  50  * wm8400_init - Generic initialisation
  51  *
  52  * The WM8400 can be configured as either an I2C or SPI device.  Probe
  53  * functions for each bus set up the accessors then call into this to
  54  * set up the device itself.
  55  */
  56 static int wm8400_init(struct wm8400 *wm8400,
  57                        struct wm8400_platform_data *pdata)
  58 {
  59         unsigned int reg;
  60         int ret;
  61
  62         dev_set_drvdata(wm8400->dev, wm8400);
  63
  64         /* Check that this is actually a WM8400 */
  65         ret = regmap_read(wm8400->regmap, WM8400_RESET_ID, &reg);
  66         if (ret != 0) {
  67                 dev_err(wm8400->dev, "Chip ID register read failed\n");
  68                 return -EIO;
  69         }
  70         if (reg != 0x6172) {
  71                 dev_err(wm8400->dev, "Device is not a WM8400, ID is %x\n",
  72                         reg);
  73                 return -ENODEV;
  74         }
  75
  76         ret = regmap_read(wm8400->regmap, WM8400_ID, &reg);
  77         if (ret != 0) {
  78                 dev_err(wm8400->dev, "ID register read failed: %d\n", ret);
  79                 return ret;
  80         }
  81         reg = (reg & WM8400_CHIP_REV_MASK) >> WM8400_CHIP_REV_SHIFT;
  82         dev_info(wm8400->dev, "WM8400 revision %x\n", reg);
  83
  84         ret = wm8400_register_codec(wm8400);
  85         if (ret != 0) {
  86                 dev_err(wm8400->dev, "Failed to register codec\n");
  87                 return ret;
  88         }
  89
  90         if (pdata && pdata->platform_init) {
  91                 ret = pdata->platform_init(wm8400->dev);
  92                 if (ret != 0) {
  93                         dev_err(wm8400->dev, "Platform init failed: %d\n",
  94                                 ret);
  95                         return ret;
  96                 }
  97         } else
  98                 dev_warn(wm8400->dev, "No platform initialisation supplied\n");
  99
 100         return 0;
 101 }
 102
 103 static const struct regmap_config wm8400_regmap_config = {
 104         .reg_bits = 8,
 105         .val_bits = 16,
 106         .max_register = WM8400_REGISTER_COUNT - 1,
 107
 108         .volatile_reg = wm8400_volatile,
 109
 110         .cache_type = REGCACHE_RBTREE,
 111 };
 112
 113 /**
 114  * wm8400_reset_codec_reg_cache - Reset cached codec registers to
 115  * their default values.
 116  */
 117 void wm8400_reset_codec_reg_cache(struct wm8400 *wm8400)
 118 {
 119         regmap_reinit_cache(wm8400->regmap, &wm8400_regmap_config);
 120 }
 121 EXPORT_SYMBOL_GPL(wm8400_reset_codec_reg_cache);
 122
 123 #if IS_ENABLED(CONFIG_I2C)
 124 static int wm8400_i2c_probe(struct i2c_client *i2c,
 125                             const struct i2c_device_id *id)
 126 {
 127         struct wm8400 *wm8400;
 128
 129         wm8400 = devm_kzalloc(&i2c->dev, sizeof(struct wm8400), GFP_KERNEL);
 130         if (!wm8400)
 131                 return -ENOMEM;
 132
 133         wm8400->regmap = devm_regmap_init_i2c(i2c, &wm8400_regmap_config);
 134         if (IS_ERR(wm8400->regmap))
 135                 return PTR_ERR(wm8400->regmap);
 136
 137         wm8400->dev = &i2c->dev;
 138         i2c_set_clientdata(i2c, wm8400);
 139
 140         return wm8400_init(wm8400, dev_get_platdata(&i2c->dev));
 141 }
 142
 143 static const struct i2c_device_id wm8400_i2c_id[] = {
 144        { "wm8400", 0 },
 145        { }
 146 };
 147
 148 static struct i2c_driver wm8400_i2c_driver = {
 149         .driver = {
 150                 .name = "WM8400",
 151         },
 152         .probe    = wm8400_i2c_probe,
 153         .id_table = wm8400_i2c_id,
 154 };
 155 #endif
 156
 157 static int __init wm8400_driver_init(void)
 158 {
 159         int ret = -ENODEV;
 160
 161 #if IS_ENABLED(CONFIG_I2C)
 162         ret = i2c_add_driver(&wm8400_i2c_driver);
 163         if (ret != 0)
 164                 pr_err("Failed to register I2C driver: %d\n", ret);
 165 #endif
 166
 167         return ret;
 168 }
 169 subsys_initcall(wm8400_driver_init);