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 int wm8400_block_read(struct wm8400 *wm8400, u8 reg, int count, u16 *data)
  39 {
  40         return regmap_bulk_read(wm8400->regmap, reg, data, count);
  41 }
  42 EXPORT_SYMBOL_GPL(wm8400_block_read);
  43
  44 static int wm8400_register_codec(struct wm8400 *wm8400)
  45 {
  46         const struct mfd_cell cell = {
  47                 .name = "wm8400-codec",
  48                 .platform_data = wm8400,
  49                 .pdata_size = sizeof(*wm8400),
  50         };
  51
  52         return devm_mfd_add_devices(wm8400->dev, -1, &cell, 1, NULL, 0, NULL);
  53 }
  54
  55 /*
  56  * wm8400_init - Generic initialisation
  57  *
  58  * The WM8400 can be configured as either an I2C or SPI device.  Probe
  59  * functions for each bus set up the accessors then call into this to
  60  * set up the device itself.
  61  */
  62 static int wm8400_init(struct wm8400 *wm8400,
  63                        struct wm8400_platform_data *pdata)
  64 {
  65         unsigned int reg;
  66         int ret;
  67
  68         dev_set_drvdata(wm8400->dev, wm8400);
  69
  70         /* Check that this is actually a WM8400 */
  71         ret = regmap_read(wm8400->regmap, WM8400_RESET_ID, &reg);
  72         if (ret != 0) {
  73                 dev_err(wm8400->dev, "Chip ID register read failed\n");
  74                 return -EIO;
  75         }
  76         if (reg != 0x6172) {
  77                 dev_err(wm8400->dev, "Device is not a WM8400, ID is %x\n",
  78                         reg);
  79                 return -ENODEV;
  80         }
  81
  82         ret = regmap_read(wm8400->regmap, WM8400_ID, &reg);
  83         if (ret != 0) {
  84                 dev_err(wm8400->dev, "ID register read failed: %d\n", ret);
  85                 return ret;
  86         }
  87         reg = (reg & WM8400_CHIP_REV_MASK) >> WM8400_CHIP_REV_SHIFT;
  88         dev_info(wm8400->dev, "WM8400 revision %x\n", reg);
  89
  90         ret = wm8400_register_codec(wm8400);
  91         if (ret != 0) {
  92                 dev_err(wm8400->dev, "Failed to register codec\n");
  93                 return ret;
  94         }
  95
  96         if (pdata && pdata->platform_init) {
  97                 ret = pdata->platform_init(wm8400->dev);
  98                 if (ret != 0) {
  99                         dev_err(wm8400->dev, "Platform init failed: %d\n",
 100                                 ret);
 101                         return ret;
 102                 }
 103         } else
 104                 dev_warn(wm8400->dev, "No platform initialisation supplied\n");
 105
 106         return 0;
 107 }
 108
 109 static const struct regmap_config wm8400_regmap_config = {
 110         .reg_bits = 8,
 111         .val_bits = 16,
 112         .max_register = WM8400_REGISTER_COUNT - 1,
 113
 114         .volatile_reg = wm8400_volatile,
 115
 116         .cache_type = REGCACHE_RBTREE,
 117 };
 118
 119 /**
 120  * wm8400_reset_codec_reg_cache - Reset cached codec registers to
 121  * their default values.
 122  */
 123 void wm8400_reset_codec_reg_cache(struct wm8400 *wm8400)
 124 {
 125         regmap_reinit_cache(wm8400->regmap, &wm8400_regmap_config);
 126 }
 127 EXPORT_SYMBOL_GPL(wm8400_reset_codec_reg_cache);
 128
 129 #if IS_ENABLED(CONFIG_I2C)
 130 static int wm8400_i2c_probe(struct i2c_client *i2c,
 131                             const struct i2c_device_id *id)
 132 {
 133         struct wm8400 *wm8400;
 134
 135         wm8400 = devm_kzalloc(&i2c->dev, sizeof(struct wm8400), GFP_KERNEL);
 136         if (!wm8400)
 137                 return -ENOMEM;
 138
 139         wm8400->regmap = devm_regmap_init_i2c(i2c, &wm8400_regmap_config);
 140         if (IS_ERR(wm8400->regmap))
 141                 return PTR_ERR(wm8400->regmap);
 142
 143         wm8400->dev = &i2c->dev;
 144         i2c_set_clientdata(i2c, wm8400);
 145
 146         return wm8400_init(wm8400, dev_get_platdata(&i2c->dev));
 147 }
 148
 149 static const struct i2c_device_id wm8400_i2c_id[] = {
 150        { "wm8400", 0 },
 151        { }
 152 };
 153
 154 static struct i2c_driver wm8400_i2c_driver = {
 155         .driver = {
 156                 .name = "WM8400",
 157         },
 158         .probe    = wm8400_i2c_probe,
 159         .id_table = wm8400_i2c_id,
 160 };
 161 #endif
 162
 163 static int __init wm8400_driver_init(void)
 164 {
 165         int ret = -ENODEV;
 166
 167 #if IS_ENABLED(CONFIG_I2C)
 168         ret = i2c_add_driver(&wm8400_i2c_driver);
 169         if (ret != 0)
 170                 pr_err("Failed to register I2C driver: %d\n", ret);
 171 #endif
 172
 173         return ret;
 174 }
 175 subsys_initcall(wm8400_driver_init);