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