i2c: Constify i2c_algorithm declarations, part 2
[linux-2.6.git] / drivers / i2c / busses / i2c-stub.c
1 /*
2     i2c-stub.c - Part of lm_sensors, Linux kernel modules for hardware
3               monitoring
4
5     Copyright (c) 2004 Mark M. Hoffman <mhoffman@lightlink.com>
6
7     This program is free software; you can redistribute it and/or modify
8     it under the terms of the GNU General Public License as published by
9     the Free Software Foundation; either version 2 of the License, or
10     (at your option) any later version.
11
12     This program is distributed in the hope that it will be useful,
13     but WITHOUT ANY WARRANTY; without even the implied warranty of
14     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15     GNU General Public License for more details.
16
17     You should have received a copy of the GNU General Public License
18     along with this program; if not, write to the Free Software
19     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
20 */
21
22 #define DEBUG 1
23
24 #include <linux/init.h>
25 #include <linux/module.h>
26 #include <linux/kernel.h>
27 #include <linux/errno.h>
28 #include <linux/i2c.h>
29
30 static unsigned short chip_addr;
31 module_param(chip_addr, ushort, S_IRUGO);
32 MODULE_PARM_DESC(chip_addr, "Chip address (between 0x03 and 0x77)\n");
33
34 static u8  stub_pointer;
35 static u8  stub_bytes[256];
36 static u16 stub_words[256];
37
38 /* Return -1 on error. */
39 static s32 stub_xfer(struct i2c_adapter * adap, u16 addr, unsigned short flags,
40         char read_write, u8 command, int size, union i2c_smbus_data * data)
41 {
42         s32 ret;
43
44         if (addr != chip_addr)
45                 return -ENODEV;
46
47         switch (size) {
48
49         case I2C_SMBUS_QUICK:
50                 dev_dbg(&adap->dev, "smbus quick - addr 0x%02x\n", addr);
51                 ret = 0;
52                 break;
53
54         case I2C_SMBUS_BYTE:
55                 if (read_write == I2C_SMBUS_WRITE) {
56                         stub_pointer = command;
57                         dev_dbg(&adap->dev, "smbus byte - addr 0x%02x, "
58                                         "wrote 0x%02x.\n",
59                                         addr, command);
60                 } else {
61                         data->byte = stub_bytes[stub_pointer++];
62                         dev_dbg(&adap->dev, "smbus byte - addr 0x%02x, "
63                                         "read  0x%02x.\n",
64                                         addr, data->byte);
65                 }
66
67                 ret = 0;
68                 break;
69
70         case I2C_SMBUS_BYTE_DATA:
71                 if (read_write == I2C_SMBUS_WRITE) {
72                         stub_bytes[command] = data->byte;
73                         dev_dbg(&adap->dev, "smbus byte data - addr 0x%02x, "
74                                         "wrote 0x%02x at 0x%02x.\n",
75                                         addr, data->byte, command);
76                 } else {
77                         data->byte = stub_bytes[command];
78                         dev_dbg(&adap->dev, "smbus byte data - addr 0x%02x, "
79                                         "read  0x%02x at 0x%02x.\n",
80                                         addr, data->byte, command);
81                 }
82                 stub_pointer = command + 1;
83
84                 ret = 0;
85                 break;
86
87         case I2C_SMBUS_WORD_DATA:
88                 if (read_write == I2C_SMBUS_WRITE) {
89                         stub_words[command] = data->word;
90                         dev_dbg(&adap->dev, "smbus word data - addr 0x%02x, "
91                                         "wrote 0x%04x at 0x%02x.\n",
92                                         addr, data->word, command);
93                 } else {
94                         data->word = stub_words[command];
95                         dev_dbg(&adap->dev, "smbus word data - addr 0x%02x, "
96                                         "read  0x%04x at 0x%02x.\n",
97                                         addr, data->word, command);
98                 }
99
100                 ret = 0;
101                 break;
102
103         default:
104                 dev_dbg(&adap->dev, "Unsupported I2C/SMBus command\n");
105                 ret = -1;
106                 break;
107         } /* switch (size) */
108
109         return ret;
110 }
111
112 static u32 stub_func(struct i2c_adapter *adapter)
113 {
114         return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
115                 I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA;
116 }
117
118 static const struct i2c_algorithm smbus_algorithm = {
119         .functionality  = stub_func,
120         .smbus_xfer     = stub_xfer,
121 };
122
123 static struct i2c_adapter stub_adapter = {
124         .owner          = THIS_MODULE,
125         .class          = I2C_CLASS_HWMON,
126         .algo           = &smbus_algorithm,
127         .name           = "SMBus stub driver",
128 };
129
130 static int __init i2c_stub_init(void)
131 {
132         if (!chip_addr) {
133                 printk(KERN_ERR "i2c-stub: Please specify a chip address\n");
134                 return -ENODEV;
135         }
136         if (chip_addr < 0x03 || chip_addr > 0x77) {
137                 printk(KERN_ERR "i2c-stub: Invalid chip address 0x%02x\n",
138                        chip_addr);
139                 return -EINVAL;
140         }
141
142         printk(KERN_INFO "i2c-stub: Virtual chip at 0x%02x\n", chip_addr);
143         return i2c_add_adapter(&stub_adapter);
144 }
145
146 static void __exit i2c_stub_exit(void)
147 {
148         i2c_del_adapter(&stub_adapter);
149 }
150
151 MODULE_AUTHOR("Mark M. Hoffman <mhoffman@lightlink.com>");
152 MODULE_DESCRIPTION("I2C stub driver");
153 MODULE_LICENSE("GPL");
154
155 module_init(i2c_stub_init);
156 module_exit(i2c_stub_exit);
157