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 
wm8400_volatile(struct device * dev,unsigned int reg)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 
wm8400_register_codec(struct wm8400 * wm8400)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  */
wm8400_init(struct wm8400 * wm8400,struct wm8400_platform_data * pdata)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  */
wm8400_reset_codec_reg_cache(struct wm8400 * wm8400)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)
wm8400_i2c_probe(struct i2c_client * i2c,const struct i2c_device_id * id)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 
wm8400_driver_init(void)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);
167