LXR linux/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
  21static 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
  33static 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 */
  51static 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
  98static 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 */
 112void wm8400_reset_codec_reg_cache(struct wm8400 *wm8400)
 113{
 114        regmap_reinit_cache(wm8400->regmap, &wm8400_regmap_config);
 115}
 116EXPORT_SYMBOL_GPL(wm8400_reset_codec_reg_cache);
 117
 118#if IS_ENABLED(CONFIG_I2C)
 119static int wm8400_i2c_probe(struct i2c_client *i2c,
 120                            const struct i2c_device_id *id)
 121{
 122        struct wm8400 *wm8400;
 123
 124        wm8400 = devm_kzalloc(&i2c->dev, sizeof(struct wm8400), GFP_KERNEL);
 125        if (!wm8400)
 126                return -ENOMEM;
 127
 128        wm8400->regmap = devm_regmap_init_i2c(i2c, &wm8400_regmap_config);
 129        if (IS_ERR(wm8400->regmap))
 130                return PTR_ERR(wm8400->regmap);
 131
 132        wm8400->dev = &i2c->dev;
 133        i2c_set_clientdata(i2c, wm8400);
 134
 135        return wm8400_init(wm8400, dev_get_platdata(&i2c->dev));
 136}
 137
 138static const struct i2c_device_id wm8400_i2c_id[] = {
 139       { "wm8400", 0 },
 140       { }
 141};
 142
 143static struct i2c_driver wm8400_i2c_driver = {
 144        .driver = {
 145                .name = "WM8400",
 146        },
 147        .probe    = wm8400_i2c_probe,
 148        .id_table = wm8400_i2c_id,
 149};
 150#endif
 151
 152static int __init wm8400_driver_init(void)
 153{
 154        int ret = -ENODEV;
 155
 156#if IS_ENABLED(CONFIG_I2C)
 157        ret = i2c_add_driver(&wm8400_i2c_driver);
 158        if (ret != 0)
 159                pr_err("Failed to register I2C driver: %d\n", ret);
 160#endif
 161
 162        return ret;
 163}
 164subsys_initcall(wm8400_driver_init);
 165