5113f6f70
 김현기
kernel add
|
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
|
/*
* i2c-amd756-s4882.c - i2c-amd756 extras for the Tyan S4882 motherboard
*
* Copyright (C) 2004, 2008 Jean Delvare <jdelvare@suse.de>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
/*
* We select the channels by sending commands to the Philips
* PCA9556 chip at I2C address 0x18. The main adapter is used for
* the non-multiplexed part of the bus, and 4 virtual adapters
* are defined for the multiplexed addresses: 0x50-0x53 (memory
* module EEPROM) located on channels 1-4, and 0x4c (LM63)
* located on multiplexed channels 0 and 5-7. We define one
* virtual adapter per CPU, which corresponds to two multiplexed
* channels:
* CPU0: virtual adapter 1, channels 1 and 0
* CPU1: virtual adapter 2, channels 2 and 5
* CPU2: virtual adapter 3, channels 3 and 6
* CPU3: virtual adapter 4, channels 4 and 7
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/i2c.h>
#include <linux/mutex.h>
extern struct i2c_adapter amd756_smbus;
static struct i2c_adapter *s4882_adapter;
static struct i2c_algorithm *s4882_algo;
/* Wrapper access functions for multiplexed SMBus */
static DEFINE_MUTEX(amd756_lock);
static s32 amd756_access_virt0(struct i2c_adapter * adap, u16 addr,
unsigned short flags, char read_write,
u8 command, int size,
union i2c_smbus_data * data)
{
int error;
/* We exclude the multiplexed addresses */
if (addr == 0x4c || (addr & 0xfc) == 0x50 || (addr & 0xfc) == 0x30
|| addr == 0x18)
return -ENXIO;
mutex_lock(&amd756_lock);
error = amd756_smbus.algo->smbus_xfer(adap, addr, flags, read_write,
command, size, data);
mutex_unlock(&amd756_lock);
return error;
}
/* We remember the last used channels combination so as to only switch
channels when it is really needed. This greatly reduces the SMBus
overhead, but also assumes that nobody will be writing to the PCA9556
in our back. */
static u8 last_channels;
static inline s32 amd756_access_channel(struct i2c_adapter * adap, u16 addr,
unsigned short flags, char read_write,
u8 command, int size,
union i2c_smbus_data * data,
u8 channels)
{
int error;
/* We exclude the non-multiplexed addresses */
if (addr != 0x4c && (addr & 0xfc) != 0x50 && (addr & 0xfc) != 0x30)
return -ENXIO;
mutex_lock(&amd756_lock);
if (last_channels != channels) {
union i2c_smbus_data mplxdata;
mplxdata.byte = channels;
error = amd756_smbus.algo->smbus_xfer(adap, 0x18, 0,
I2C_SMBUS_WRITE, 0x01,
I2C_SMBUS_BYTE_DATA,
&mplxdata);
if (error)
goto UNLOCK;
last_channels = channels;
}
error = amd756_smbus.algo->smbus_xfer(adap, addr, flags, read_write,
command, size, data);
UNLOCK:
mutex_unlock(&amd756_lock);
return error;
}
static s32 amd756_access_virt1(struct i2c_adapter * adap, u16 addr,
unsigned short flags, char read_write,
u8 command, int size,
union i2c_smbus_data * data)
{
/* CPU0: channels 1 and 0 enabled */
return amd756_access_channel(adap, addr, flags, read_write, command,
size, data, 0x03);
}
static s32 amd756_access_virt2(struct i2c_adapter * adap, u16 addr,
unsigned short flags, char read_write,
u8 command, int size,
union i2c_smbus_data * data)
{
/* CPU1: channels 2 and 5 enabled */
return amd756_access_channel(adap, addr, flags, read_write, command,
size, data, 0x24);
}
static s32 amd756_access_virt3(struct i2c_adapter * adap, u16 addr,
unsigned short flags, char read_write,
u8 command, int size,
union i2c_smbus_data * data)
{
/* CPU2: channels 3 and 6 enabled */
return amd756_access_channel(adap, addr, flags, read_write, command,
size, data, 0x48);
}
static s32 amd756_access_virt4(struct i2c_adapter * adap, u16 addr,
unsigned short flags, char read_write,
u8 command, int size,
union i2c_smbus_data * data)
{
/* CPU3: channels 4 and 7 enabled */
return amd756_access_channel(adap, addr, flags, read_write, command,
size, data, 0x90);
}
static int __init amd756_s4882_init(void)
{
int i, error;
union i2c_smbus_data ioconfig;
if (!amd756_smbus.dev.parent)
return -ENODEV;
/* Configure the PCA9556 multiplexer */
ioconfig.byte = 0x00; /* All I/O to output mode */
error = i2c_smbus_xfer(&amd756_smbus, 0x18, 0, I2C_SMBUS_WRITE, 0x03,
I2C_SMBUS_BYTE_DATA, &ioconfig);
if (error) {
dev_err(&amd756_smbus.dev, "PCA9556 configuration failed
");
error = -EIO;
goto ERROR0;
}
/* Unregister physical bus */
i2c_del_adapter(&amd756_smbus);
printk(KERN_INFO "Enabling SMBus multiplexing for Tyan S4882
");
/* Define the 5 virtual adapters and algorithms structures */
if (!(s4882_adapter = kzalloc(5 * sizeof(struct i2c_adapter),
GFP_KERNEL))) {
error = -ENOMEM;
goto ERROR1;
}
if (!(s4882_algo = kzalloc(5 * sizeof(struct i2c_algorithm),
GFP_KERNEL))) {
error = -ENOMEM;
goto ERROR2;
}
/* Fill in the new structures */
s4882_algo[0] = *(amd756_smbus.algo);
s4882_algo[0].smbus_xfer = amd756_access_virt0;
s4882_adapter[0] = amd756_smbus;
s4882_adapter[0].algo = s4882_algo;
s4882_adapter[0].dev.parent = amd756_smbus.dev.parent;
for (i = 1; i < 5; i++) {
s4882_algo[i] = *(amd756_smbus.algo);
s4882_adapter[i] = amd756_smbus;
snprintf(s4882_adapter[i].name, sizeof(s4882_adapter[i].name),
"SMBus 8111 adapter (CPU%d)", i-1);
s4882_adapter[i].algo = s4882_algo+i;
s4882_adapter[i].dev.parent = amd756_smbus.dev.parent;
}
s4882_algo[1].smbus_xfer = amd756_access_virt1;
s4882_algo[2].smbus_xfer = amd756_access_virt2;
s4882_algo[3].smbus_xfer = amd756_access_virt3;
s4882_algo[4].smbus_xfer = amd756_access_virt4;
/* Register virtual adapters */
for (i = 0; i < 5; i++) {
error = i2c_add_adapter(s4882_adapter+i);
if (error) {
printk(KERN_ERR "i2c-amd756-s4882: "
"Virtual adapter %d registration "
"failed, module not inserted
", i);
for (i--; i >= 0; i--)
i2c_del_adapter(s4882_adapter+i);
goto ERROR3;
}
}
return 0;
ERROR3:
kfree(s4882_algo);
s4882_algo = NULL;
ERROR2:
kfree(s4882_adapter);
s4882_adapter = NULL;
ERROR1:
/* Restore physical bus */
i2c_add_adapter(&amd756_smbus);
ERROR0:
return error;
}
static void __exit amd756_s4882_exit(void)
{
if (s4882_adapter) {
int i;
for (i = 0; i < 5; i++)
i2c_del_adapter(s4882_adapter+i);
kfree(s4882_adapter);
s4882_adapter = NULL;
}
kfree(s4882_algo);
s4882_algo = NULL;
/* Restore physical bus */
if (i2c_add_adapter(&amd756_smbus))
printk(KERN_ERR "i2c-amd756-s4882: "
"Physical bus restoration failed
");
}
MODULE_AUTHOR("Jean Delvare <jdelvare@suse.de>");
MODULE_DESCRIPTION("S4882 SMBus multiplexing");
MODULE_LICENSE("GPL");
module_init(amd756_s4882_init);
module_exit(amd756_s4882_exit);
|