Commit | Line | Data |
---|---|---|
1da177e4 | 1 | /* |
569be443 | 2 | i2c-stub.c - I2C/SMBus chip emulator |
1da177e4 LT |
3 | |
4 | Copyright (c) 2004 Mark M. Hoffman <mhoffman@lightlink.com> | |
569be443 | 5 | Copyright (C) 2007 Jean Delvare <khali@linux-fr.org> |
1da177e4 LT |
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 | ||
1da177e4 LT |
24 | #include <linux/init.h> |
25 | #include <linux/module.h> | |
26 | #include <linux/kernel.h> | |
9d90c1fd | 27 | #include <linux/slab.h> |
1da177e4 LT |
28 | #include <linux/errno.h> |
29 | #include <linux/i2c.h> | |
30 | ||
9d90c1fd | 31 | #define MAX_CHIPS 10 |
7a8d29ce | 32 | |
9d90c1fd JD |
33 | static unsigned short chip_addr[MAX_CHIPS]; |
34 | module_param_array(chip_addr, ushort, NULL, S_IRUGO); | |
35 | MODULE_PARM_DESC(chip_addr, | |
85d6931c | 36 | "Chip addresses (up to 10, between 0x03 and 0x77)"); |
9d90c1fd JD |
37 | |
38 | struct stub_chip { | |
39 | u8 pointer; | |
569be443 JD |
40 | u16 words[256]; /* Byte operations use the LSB as per SMBus |
41 | specification */ | |
9d90c1fd JD |
42 | }; |
43 | ||
44 | static struct stub_chip *stub_chips; | |
1da177e4 | 45 | |
97140342 | 46 | /* Return negative errno on error. */ |
1da177e4 LT |
47 | static s32 stub_xfer(struct i2c_adapter * adap, u16 addr, unsigned short flags, |
48 | char read_write, u8 command, int size, union i2c_smbus_data * data) | |
49 | { | |
50 | s32 ret; | |
9d90c1fd JD |
51 | int i; |
52 | struct stub_chip *chip = NULL; | |
53 | ||
54 | /* Search for the right chip */ | |
55 | for (i = 0; i < MAX_CHIPS && chip_addr[i]; i++) { | |
56 | if (addr == chip_addr[i]) { | |
57 | chip = stub_chips + i; | |
58 | break; | |
59 | } | |
60 | } | |
61 | if (!chip) | |
7a8d29ce JD |
62 | return -ENODEV; |
63 | ||
1da177e4 LT |
64 | switch (size) { |
65 | ||
66 | case I2C_SMBUS_QUICK: | |
67 | dev_dbg(&adap->dev, "smbus quick - addr 0x%02x\n", addr); | |
68 | ret = 0; | |
69 | break; | |
70 | ||
71 | case I2C_SMBUS_BYTE: | |
72 | if (read_write == I2C_SMBUS_WRITE) { | |
9d90c1fd | 73 | chip->pointer = command; |
1da177e4 LT |
74 | dev_dbg(&adap->dev, "smbus byte - addr 0x%02x, " |
75 | "wrote 0x%02x.\n", | |
76 | addr, command); | |
77 | } else { | |
569be443 | 78 | data->byte = chip->words[chip->pointer++] & 0xff; |
1da177e4 LT |
79 | dev_dbg(&adap->dev, "smbus byte - addr 0x%02x, " |
80 | "read 0x%02x.\n", | |
81 | addr, data->byte); | |
82 | } | |
83 | ||
84 | ret = 0; | |
85 | break; | |
86 | ||
87 | case I2C_SMBUS_BYTE_DATA: | |
88 | if (read_write == I2C_SMBUS_WRITE) { | |
569be443 JD |
89 | chip->words[command] &= 0xff00; |
90 | chip->words[command] |= data->byte; | |
1da177e4 LT |
91 | dev_dbg(&adap->dev, "smbus byte data - addr 0x%02x, " |
92 | "wrote 0x%02x at 0x%02x.\n", | |
93 | addr, data->byte, command); | |
94 | } else { | |
569be443 | 95 | data->byte = chip->words[command] & 0xff; |
1da177e4 LT |
96 | dev_dbg(&adap->dev, "smbus byte data - addr 0x%02x, " |
97 | "read 0x%02x at 0x%02x.\n", | |
98 | addr, data->byte, command); | |
99 | } | |
9d90c1fd | 100 | chip->pointer = command + 1; |
1da177e4 LT |
101 | |
102 | ret = 0; | |
103 | break; | |
104 | ||
105 | case I2C_SMBUS_WORD_DATA: | |
106 | if (read_write == I2C_SMBUS_WRITE) { | |
9d90c1fd | 107 | chip->words[command] = data->word; |
1da177e4 LT |
108 | dev_dbg(&adap->dev, "smbus word data - addr 0x%02x, " |
109 | "wrote 0x%04x at 0x%02x.\n", | |
110 | addr, data->word, command); | |
111 | } else { | |
9d90c1fd | 112 | data->word = chip->words[command]; |
1da177e4 LT |
113 | dev_dbg(&adap->dev, "smbus word data - addr 0x%02x, " |
114 | "read 0x%04x at 0x%02x.\n", | |
115 | addr, data->word, command); | |
116 | } | |
117 | ||
118 | ret = 0; | |
119 | break; | |
120 | ||
121 | default: | |
122 | dev_dbg(&adap->dev, "Unsupported I2C/SMBus command\n"); | |
97140342 | 123 | ret = -EOPNOTSUPP; |
1da177e4 LT |
124 | break; |
125 | } /* switch (size) */ | |
126 | ||
127 | return ret; | |
128 | } | |
129 | ||
130 | static u32 stub_func(struct i2c_adapter *adapter) | |
131 | { | |
132 | return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE | | |
133 | I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA; | |
134 | } | |
135 | ||
8f9082c5 | 136 | static const struct i2c_algorithm smbus_algorithm = { |
1da177e4 LT |
137 | .functionality = stub_func, |
138 | .smbus_xfer = stub_xfer, | |
139 | }; | |
140 | ||
141 | static struct i2c_adapter stub_adapter = { | |
142 | .owner = THIS_MODULE, | |
143 | .class = I2C_CLASS_HWMON, | |
144 | .algo = &smbus_algorithm, | |
145 | .name = "SMBus stub driver", | |
146 | }; | |
147 | ||
148 | static int __init i2c_stub_init(void) | |
149 | { | |
9d90c1fd JD |
150 | int i, ret; |
151 | ||
152 | if (!chip_addr[0]) { | |
7a8d29ce JD |
153 | printk(KERN_ERR "i2c-stub: Please specify a chip address\n"); |
154 | return -ENODEV; | |
155 | } | |
9d90c1fd JD |
156 | |
157 | for (i = 0; i < MAX_CHIPS && chip_addr[i]; i++) { | |
158 | if (chip_addr[i] < 0x03 || chip_addr[i] > 0x77) { | |
159 | printk(KERN_ERR "i2c-stub: Invalid chip address " | |
160 | "0x%02x\n", chip_addr[i]); | |
161 | return -EINVAL; | |
162 | } | |
163 | ||
164 | printk(KERN_INFO "i2c-stub: Virtual chip at 0x%02x\n", | |
165 | chip_addr[i]); | |
7a8d29ce JD |
166 | } |
167 | ||
9d90c1fd JD |
168 | /* Allocate memory for all chips at once */ |
169 | stub_chips = kzalloc(i * sizeof(struct stub_chip), GFP_KERNEL); | |
170 | if (!stub_chips) { | |
171 | printk(KERN_ERR "i2c-stub: Out of memory\n"); | |
172 | return -ENOMEM; | |
173 | } | |
174 | ||
175 | ret = i2c_add_adapter(&stub_adapter); | |
176 | if (ret) | |
177 | kfree(stub_chips); | |
178 | return ret; | |
1da177e4 LT |
179 | } |
180 | ||
181 | static void __exit i2c_stub_exit(void) | |
182 | { | |
183 | i2c_del_adapter(&stub_adapter); | |
9d90c1fd | 184 | kfree(stub_chips); |
1da177e4 LT |
185 | } |
186 | ||
187 | MODULE_AUTHOR("Mark M. Hoffman <mhoffman@lightlink.com>"); | |
188 | MODULE_DESCRIPTION("I2C stub driver"); | |
189 | MODULE_LICENSE("GPL"); | |
190 | ||
191 | module_init(i2c_stub_init); | |
192 | module_exit(i2c_stub_exit); | |
193 |