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Diffstat (limited to 'drivers/i2c/busses/i2c-stub.c')
-rw-r--r--drivers/i2c/busses/i2c-stub.c143
1 files changed, 143 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-stub.c b/drivers/i2c/busses/i2c-stub.c
new file mode 100644
index 000000000000..19c805ead4d8
--- /dev/null
+++ b/drivers/i2c/busses/i2c-stub.c
@@ -0,0 +1,143 @@
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/config.h>
25#include <linux/init.h>
26#include <linux/module.h>
27#include <linux/kernel.h>
28#include <linux/errno.h>
29#include <linux/i2c.h>
30
31static u8 stub_pointer;
32static u8 stub_bytes[256];
33static u16 stub_words[256];
34
35/* Return -1 on error. */
36static s32 stub_xfer(struct i2c_adapter * adap, u16 addr, unsigned short flags,
37 char read_write, u8 command, int size, union i2c_smbus_data * data)
38{
39 s32 ret;
40
41 switch (size) {
42
43 case I2C_SMBUS_QUICK:
44 dev_dbg(&adap->dev, "smbus quick - addr 0x%02x\n", addr);
45 ret = 0;
46 break;
47
48 case I2C_SMBUS_BYTE:
49 if (read_write == I2C_SMBUS_WRITE) {
50 stub_pointer = command;
51 dev_dbg(&adap->dev, "smbus byte - addr 0x%02x, "
52 "wrote 0x%02x.\n",
53 addr, command);
54 } else {
55 data->byte = stub_bytes[stub_pointer++];
56 dev_dbg(&adap->dev, "smbus byte - addr 0x%02x, "
57 "read 0x%02x.\n",
58 addr, data->byte);
59 }
60
61 ret = 0;
62 break;
63
64 case I2C_SMBUS_BYTE_DATA:
65 if (read_write == I2C_SMBUS_WRITE) {
66 stub_bytes[command] = data->byte;
67 dev_dbg(&adap->dev, "smbus byte data - addr 0x%02x, "
68 "wrote 0x%02x at 0x%02x.\n",
69 addr, data->byte, command);
70 } else {
71 data->byte = stub_bytes[command];
72 dev_dbg(&adap->dev, "smbus byte data - addr 0x%02x, "
73 "read 0x%02x at 0x%02x.\n",
74 addr, data->byte, command);
75 }
76 stub_pointer = command + 1;
77
78 ret = 0;
79 break;
80
81 case I2C_SMBUS_WORD_DATA:
82 if (read_write == I2C_SMBUS_WRITE) {
83 stub_words[command] = data->word;
84 dev_dbg(&adap->dev, "smbus word data - addr 0x%02x, "
85 "wrote 0x%04x at 0x%02x.\n",
86 addr, data->word, command);
87 } else {
88 data->word = stub_words[command];
89 dev_dbg(&adap->dev, "smbus word data - addr 0x%02x, "
90 "read 0x%04x at 0x%02x.\n",
91 addr, data->word, command);
92 }
93
94 ret = 0;
95 break;
96
97 default:
98 dev_dbg(&adap->dev, "Unsupported I2C/SMBus command\n");
99 ret = -1;
100 break;
101 } /* switch (size) */
102
103 return ret;
104}
105
106static u32 stub_func(struct i2c_adapter *adapter)
107{
108 return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
109 I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA;
110}
111
112static struct i2c_algorithm smbus_algorithm = {
113 .name = "Non-I2C SMBus adapter",
114 .id = I2C_ALGO_SMBUS,
115 .functionality = stub_func,
116 .smbus_xfer = stub_xfer,
117};
118
119static struct i2c_adapter stub_adapter = {
120 .owner = THIS_MODULE,
121 .class = I2C_CLASS_HWMON,
122 .algo = &smbus_algorithm,
123 .name = "SMBus stub driver",
124};
125
126static int __init i2c_stub_init(void)
127{
128 printk(KERN_INFO "i2c-stub loaded\n");
129 return i2c_add_adapter(&stub_adapter);
130}
131
132static void __exit i2c_stub_exit(void)
133{
134 i2c_del_adapter(&stub_adapter);
135}
136
137MODULE_AUTHOR("Mark M. Hoffman <mhoffman@lightlink.com>");
138MODULE_DESCRIPTION("I2C stub driver");
139MODULE_LICENSE("GPL");
140
141module_init(i2c_stub_init);
142module_exit(i2c_stub_exit);
143