mfd: Fix twl-core oops while calling twl_i2c_* for unbound driver
[linux-2.6.git] / drivers / mfd / tps6507x.c
1 /*
2  * tps6507x.c  --  TPS6507x chip family multi-function driver
3  *
4  *  Copyright (c) 2010 RidgeRun (todd.fischer@ridgerun.com)
5  *
6  * Author: Todd Fischer
7  *         todd.fischer@ridgerun.com
8  *
9  * Credits:
10  *
11  *    Using code from wm831x-*.c, wm8400-core, Wolfson Microelectronics PLC.
12  *
13  * For licencing details see kernel-base/COPYING
14  *
15  */
16
17 #include <linux/module.h>
18 #include <linux/moduleparam.h>
19 #include <linux/init.h>
20 #include <linux/slab.h>
21 #include <linux/i2c.h>
22 #include <linux/mfd/core.h>
23 #include <linux/mfd/tps6507x.h>
24
25 static struct mfd_cell tps6507x_devs[] = {
26         {
27                 .name = "tps6507x-pmic",
28         },
29         {
30                 .name = "tps6507x-ts",
31         },
32 };
33
34
35 static int tps6507x_i2c_read_device(struct tps6507x_dev *tps6507x, char reg,
36                                   int bytes, void *dest)
37 {
38         struct i2c_client *i2c = tps6507x->i2c_client;
39         struct i2c_msg xfer[2];
40         int ret;
41
42         /* Write register */
43         xfer[0].addr = i2c->addr;
44         xfer[0].flags = 0;
45         xfer[0].len = 1;
46         xfer[0].buf = &reg;
47
48         /* Read data */
49         xfer[1].addr = i2c->addr;
50         xfer[1].flags = I2C_M_RD;
51         xfer[1].len = bytes;
52         xfer[1].buf = dest;
53
54         ret = i2c_transfer(i2c->adapter, xfer, 2);
55         if (ret == 2)
56                 ret = 0;
57         else if (ret >= 0)
58                 ret = -EIO;
59
60         return ret;
61 }
62
63 static int tps6507x_i2c_write_device(struct tps6507x_dev *tps6507x, char reg,
64                                    int bytes, void *src)
65 {
66         struct i2c_client *i2c = tps6507x->i2c_client;
67         /* we add 1 byte for device register */
68         u8 msg[TPS6507X_MAX_REGISTER + 1];
69         int ret;
70
71         if (bytes > TPS6507X_MAX_REGISTER)
72                 return -EINVAL;
73
74         msg[0] = reg;
75         memcpy(&msg[1], src, bytes);
76
77         ret = i2c_master_send(i2c, msg, bytes + 1);
78         if (ret < 0)
79                 return ret;
80         if (ret != bytes + 1)
81                 return -EIO;
82         return 0;
83 }
84
85 static int tps6507x_i2c_probe(struct i2c_client *i2c,
86                             const struct i2c_device_id *id)
87 {
88         struct tps6507x_dev *tps6507x;
89         int ret = 0;
90
91         tps6507x = kzalloc(sizeof(struct tps6507x_dev), GFP_KERNEL);
92         if (tps6507x == NULL)
93                 return -ENOMEM;
94
95         i2c_set_clientdata(i2c, tps6507x);
96         tps6507x->dev = &i2c->dev;
97         tps6507x->i2c_client = i2c;
98         tps6507x->read_dev = tps6507x_i2c_read_device;
99         tps6507x->write_dev = tps6507x_i2c_write_device;
100
101         ret = mfd_add_devices(tps6507x->dev, -1,
102                               tps6507x_devs, ARRAY_SIZE(tps6507x_devs),
103                               NULL, 0);
104
105         if (ret < 0)
106                 goto err;
107
108         return ret;
109
110 err:
111         mfd_remove_devices(tps6507x->dev);
112         kfree(tps6507x);
113         return ret;
114 }
115
116 static int tps6507x_i2c_remove(struct i2c_client *i2c)
117 {
118         struct tps6507x_dev *tps6507x = i2c_get_clientdata(i2c);
119
120         mfd_remove_devices(tps6507x->dev);
121         kfree(tps6507x);
122
123         return 0;
124 }
125
126 static const struct i2c_device_id tps6507x_i2c_id[] = {
127        { "tps6507x", 0 },
128        { }
129 };
130 MODULE_DEVICE_TABLE(i2c, tps6507x_i2c_id);
131
132
133 static struct i2c_driver tps6507x_i2c_driver = {
134         .driver = {
135                    .name = "tps6507x",
136                    .owner = THIS_MODULE,
137         },
138         .probe = tps6507x_i2c_probe,
139         .remove = tps6507x_i2c_remove,
140         .id_table = tps6507x_i2c_id,
141 };
142
143 static int __init tps6507x_i2c_init(void)
144 {
145         return i2c_add_driver(&tps6507x_i2c_driver);
146 }
147 /* init early so consumer devices can complete system boot */
148 subsys_initcall(tps6507x_i2c_init);
149
150 static void __exit tps6507x_i2c_exit(void)
151 {
152         i2c_del_driver(&tps6507x_i2c_driver);
153 }
154 module_exit(tps6507x_i2c_exit);
155
156 MODULE_DESCRIPTION("TPS6507x chip family multi-function driver");
157 MODULE_LICENSE("GPL");