drivers/mfd/wm8400-core.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Core driver for WM8400.
   4  *
   5  * Copyright 2008 Wolfson Microelectronics PLC.
   6  *
   7  * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
   8  */
   9
  10 #include <linux/init.h>
  11 #include <linux/bug.h>
  12 #include <linux/err.h>
  13 #include <linux/i2c.h>
  14 #include <linux/kernel.h>
  15 #include <linux/mfd/core.h>
  16 #include <linux/mfd/wm8400-private.h>
  17 #include <linux/mfd/wm8400-audio.h>
  18 #include <linux/regmap.h>
  19 #include <linux/slab.h>
  20
  21 static bool wm8400_volatile(struct device *dev, unsigned int reg)
  22 {
  23         switch (reg) {
  24         case WM8400_INTERRUPT_STATUS_1:
  25         case WM8400_INTERRUPT_LEVELS:
  26         case WM8400_SHUTDOWN_REASON:
  27                 return true;
  28         default:
  29                 return false;
  30         }
  31 }
  32
  33 static int wm8400_register_codec(struct wm8400 *wm8400)
  34 {
  35         const struct mfd_cell cell = {
  36                 .name = "wm8400-codec",
  37                 .platform_data = wm8400,
  38                 .pdata_size = sizeof(*wm8400),
  39         };
  40
  41         return devm_mfd_add_devices(wm8400->dev, -1, &cell, 1, NULL, 0, NULL);
  42 }
  43
  44 /*
  45  * wm8400_init - Generic initialisation
  46  *
  47  * The WM8400 can be configured as either an I2C or SPI device.  Probe
  48  * functions for each bus set up the accessors then call into this to
  49  * set up the device itself.
  50  */
  51 static int wm8400_init(struct wm8400 *wm8400,
  52                        struct wm8400_platform_data *pdata)
  53 {
  54         unsigned int reg;
  55         int ret;
  56
  57         dev_set_drvdata(wm8400->dev, wm8400);
  58
  59         /* Check that this is actually a WM8400 */
  60         ret = regmap_read(wm8400->regmap, WM8400_RESET_ID, &reg);
  61         if (ret != 0) {
  62                 dev_err(wm8400->dev, "Chip ID register read failed\n");
  63                 return -EIO;
  64         }
  65         if (reg != 0x6172) {
  66                 dev_err(wm8400->dev, "Device is not a WM8400, ID is %x\n",
  67                         reg);
  68                 return -ENODEV;
  69         }
  70
  71         ret = regmap_read(wm8400->regmap, WM8400_ID, &reg);
  72         if (ret != 0) {
  73                 dev_err(wm8400->dev, "ID register read failed: %d\n", ret);
  74                 return ret;
  75         }
  76         reg = (reg & WM8400_CHIP_REV_MASK) >> WM8400_CHIP_REV_SHIFT;
  77         dev_info(wm8400->dev, "WM8400 revision %x\n", reg);
  78
  79         ret = wm8400_register_codec(wm8400);
  80         if (ret != 0) {
  81                 dev_err(wm8400->dev, "Failed to register codec\n");
  82                 return ret;
  83         }
  84
  85         if (pdata && pdata->platform_init) {
  86                 ret = pdata->platform_init(wm8400->dev);
  87                 if (ret != 0) {
  88                         dev_err(wm8400->dev, "Platform init failed: %d\n",
  89                                 ret);
  90                         return ret;
  91                 }
  92         } else
  93                 dev_warn(wm8400->dev, "No platform initialisation supplied\n");
  94
  95         return 0;
  96 }
  97
  98 static const struct regmap_config wm8400_regmap_config = {
  99         .reg_bits = 8,
 100         .val_bits = 16,
 101         .max_register = WM8400_REGISTER_COUNT - 1,
 102
 103         .volatile_reg = wm8400_volatile,
 104
 105         .cache_type = REGCACHE_RBTREE,
 106 };
 107
 108 /**
 109  * wm8400_reset_codec_reg_cache - Reset cached codec registers to
 110  * their default values.
 111  *
 112  * @wm8400: pointer to local driver data structure
 113  */
 114 void wm8400_reset_codec_reg_cache(struct wm8400 *wm8400)
 115 {
 116         regmap_reinit_cache(wm8400->regmap, &wm8400_regmap_config);
 117 }
 118 EXPORT_SYMBOL_GPL(wm8400_reset_codec_reg_cache);
 119
 120 #if IS_ENABLED(CONFIG_I2C)
 121 static int wm8400_i2c_probe(struct i2c_client *i2c,
 122                             const struct i2c_device_id *id)
 123 {
 124         struct wm8400 *wm8400;
 125
 126         wm8400 = devm_kzalloc(&i2c->dev, sizeof(struct wm8400), GFP_KERNEL);
 127         if (!wm8400)
 128                 return -ENOMEM;
 129
 130         wm8400->regmap = devm_regmap_init_i2c(i2c, &wm8400_regmap_config);
 131         if (IS_ERR(wm8400->regmap))
 132                 return PTR_ERR(wm8400->regmap);
 133
 134         wm8400->dev = &i2c->dev;
 135         i2c_set_clientdata(i2c, wm8400);
 136
 137         return wm8400_init(wm8400, dev_get_platdata(&i2c->dev));
 138 }
 139
 140 static const struct i2c_device_id wm8400_i2c_id[] = {
 141        { "wm8400", 0 },
 142        { }
 143 };
 144
 145 static struct i2c_driver wm8400_i2c_driver = {
 146         .driver = {
 147                 .name = "WM8400",
 148         },
 149         .probe    = wm8400_i2c_probe,
 150         .id_table = wm8400_i2c_id,
 151 };
 152 #endif
 153
 154 static int __init wm8400_driver_init(void)
 155 {
 156         int ret = -ENODEV;
 157
 158 #if IS_ENABLED(CONFIG_I2C)
 159         ret = i2c_add_driver(&wm8400_i2c_driver);
 160         if (ret != 0)
 161                 pr_err("Failed to register I2C driver: %d\n", ret);
 162 #endif
 163
 164         return ret;
 165 }
 166 subsys_initcall(wm8400_driver_init);