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         /* Check that this is actually a WM8400 */
  58         ret = regmap_read(wm8400->regmap, WM8400_RESET_ID, &reg);
  59         if (ret != 0) {
  60                 dev_err(wm8400->dev, "Chip ID register read failed\n");
  61                 return -EIO;
  62         }
  63         if (reg != 0x6172) {
  64                 dev_err(wm8400->dev, "Device is not a WM8400, ID is %x\n",
  65                         reg);
  66                 return -ENODEV;
  67         }
  68
  69         ret = regmap_read(wm8400->regmap, WM8400_ID, &reg);
  70         if (ret != 0) {
  71                 dev_err(wm8400->dev, "ID register read failed: %d\n", ret);
  72                 return ret;
  73         }
  74         reg = (reg & WM8400_CHIP_REV_MASK) >> WM8400_CHIP_REV_SHIFT;
  75         dev_info(wm8400->dev, "WM8400 revision %x\n", reg);
  76
  77         ret = wm8400_register_codec(wm8400);
  78         if (ret != 0) {
  79                 dev_err(wm8400->dev, "Failed to register codec\n");
  80                 return ret;
  81         }
  82
  83         if (pdata && pdata->platform_init) {
  84                 ret = pdata->platform_init(wm8400->dev);
  85                 if (ret != 0) {
  86                         dev_err(wm8400->dev, "Platform init failed: %d\n",
  87                                 ret);
  88                         return ret;
  89                 }
  90         } else
  91                 dev_warn(wm8400->dev, "No platform initialisation supplied\n");
  92
  93         return 0;
  94 }
  95
  96 static const struct regmap_config wm8400_regmap_config = {
  97         .reg_bits = 8,
  98         .val_bits = 16,
  99         .max_register = WM8400_REGISTER_COUNT - 1,
 100
 101         .volatile_reg = wm8400_volatile,
 102
 103         .cache_type = REGCACHE_MAPLE,
 104 };
 105
 106 /**
 107  * wm8400_reset_codec_reg_cache - Reset cached codec registers to
 108  * their default values.
 109  *
 110  * @wm8400: pointer to local driver data structure
 111  */
 112 void wm8400_reset_codec_reg_cache(struct wm8400 *wm8400)
 113 {
 114         regmap_reinit_cache(wm8400->regmap, &wm8400_regmap_config);
 115 }
 116 EXPORT_SYMBOL_GPL(wm8400_reset_codec_reg_cache);
 117
 118 #if IS_ENABLED(CONFIG_I2C)
 119 static int wm8400_i2c_probe(struct i2c_client *i2c)
 120 {
 121         struct wm8400 *wm8400;
 122
 123         wm8400 = devm_kzalloc(&i2c->dev, sizeof(struct wm8400), GFP_KERNEL);
 124         if (!wm8400)
 125                 return -ENOMEM;
 126
 127         wm8400->regmap = devm_regmap_init_i2c(i2c, &wm8400_regmap_config);
 128         if (IS_ERR(wm8400->regmap))
 129                 return PTR_ERR(wm8400->regmap);
 130
 131         wm8400->dev = &i2c->dev;
 132         i2c_set_clientdata(i2c, wm8400);
 133
 134         return wm8400_init(wm8400, dev_get_platdata(&i2c->dev));
 135 }
 136
 137 static const struct i2c_device_id wm8400_i2c_id[] = {
 138        { "wm8400", 0 },
 139        { }
 140 };
 141
 142 static struct i2c_driver wm8400_i2c_driver = {
 143         .driver = {
 144                 .name = "WM8400",
 145         },
 146         .probe = wm8400_i2c_probe,
 147         .id_table = wm8400_i2c_id,
 148 };
 149 #endif
 150
 151 static int __init wm8400_driver_init(void)
 152 {
 153         int ret = -ENODEV;
 154
 155 #if IS_ENABLED(CONFIG_I2C)
 156         ret = i2c_add_driver(&wm8400_i2c_driver);
 157         if (ret != 0)
 158                 pr_err("Failed to register I2C driver: %d\n", ret);
 159 #endif
 160
 161         return ret;
 162 }
 163 subsys_initcall(wm8400_driver_init);