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1da177e4 LT |
1 | /* |
2 | * i2c-amd756-s4882.c - i2c-amd756 extras for the Tyan S4882 motherboard | |
3 | * | |
ee56d977 | 4 | * Copyright (C) 2004, 2008 Jean Delvare <khali@linux-fr.org> |
1da177e4 LT |
5 | * |
6 | * This program is free software; you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License as published by | |
8 | * the Free Software Foundation; either version 2 of the License, or | |
9 | * (at your option) any later version. | |
10 | * | |
11 | * This program is distributed in the hope that it will be useful, | |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | * GNU General Public License for more details. | |
15 | * | |
16 | * You should have received a copy of the GNU General Public License | |
17 | * along with this program; if not, write to the Free Software | |
18 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. | |
19 | */ | |
20 | ||
21 | /* | |
22 | * We select the channels by sending commands to the Philips | |
23 | * PCA9556 chip at I2C address 0x18. The main adapter is used for | |
24 | * the non-multiplexed part of the bus, and 4 virtual adapters | |
25 | * are defined for the multiplexed addresses: 0x50-0x53 (memory | |
26 | * module EEPROM) located on channels 1-4, and 0x4c (LM63) | |
27 | * located on multiplexed channels 0 and 5-7. We define one | |
28 | * virtual adapter per CPU, which corresponds to two multiplexed | |
29 | * channels: | |
30 | * CPU0: virtual adapter 1, channels 1 and 0 | |
31 | * CPU1: virtual adapter 2, channels 2 and 5 | |
32 | * CPU2: virtual adapter 3, channels 3 and 6 | |
33 | * CPU3: virtual adapter 4, channels 4 and 7 | |
34 | */ | |
35 | ||
36 | #include <linux/module.h> | |
37 | #include <linux/kernel.h> | |
38 | #include <linux/slab.h> | |
39 | #include <linux/init.h> | |
40 | #include <linux/i2c.h> | |
5c085d36 | 41 | #include <linux/mutex.h> |
1da177e4 LT |
42 | |
43 | extern struct i2c_adapter amd756_smbus; | |
44 | ||
45 | static struct i2c_adapter *s4882_adapter; | |
46 | static struct i2c_algorithm *s4882_algo; | |
47 | ||
48 | /* Wrapper access functions for multiplexed SMBus */ | |
d7d2fe38 | 49 | static DEFINE_MUTEX(amd756_lock); |
1da177e4 LT |
50 | |
51 | static s32 amd756_access_virt0(struct i2c_adapter * adap, u16 addr, | |
52 | unsigned short flags, char read_write, | |
53 | u8 command, int size, | |
54 | union i2c_smbus_data * data) | |
55 | { | |
56 | int error; | |
57 | ||
58 | /* We exclude the multiplexed addresses */ | |
59 | if (addr == 0x4c || (addr & 0xfc) == 0x50 || (addr & 0xfc) == 0x30 | |
60 | || addr == 0x18) | |
97140342 | 61 | return -ENXIO; |
1da177e4 | 62 | |
5c085d36 | 63 | mutex_lock(&amd756_lock); |
1da177e4 LT |
64 | |
65 | error = amd756_smbus.algo->smbus_xfer(adap, addr, flags, read_write, | |
66 | command, size, data); | |
67 | ||
5c085d36 | 68 | mutex_unlock(&amd756_lock); |
1da177e4 LT |
69 | |
70 | return error; | |
71 | } | |
72 | ||
73 | /* We remember the last used channels combination so as to only switch | |
74 | channels when it is really needed. This greatly reduces the SMBus | |
75 | overhead, but also assumes that nobody will be writing to the PCA9556 | |
76 | in our back. */ | |
77 | static u8 last_channels; | |
78 | ||
79 | static inline s32 amd756_access_channel(struct i2c_adapter * adap, u16 addr, | |
80 | unsigned short flags, char read_write, | |
81 | u8 command, int size, | |
82 | union i2c_smbus_data * data, | |
83 | u8 channels) | |
84 | { | |
85 | int error; | |
86 | ||
87 | /* We exclude the non-multiplexed addresses */ | |
88 | if (addr != 0x4c && (addr & 0xfc) != 0x50 && (addr & 0xfc) != 0x30) | |
97140342 | 89 | return -ENXIO; |
1da177e4 | 90 | |
5c085d36 | 91 | mutex_lock(&amd756_lock); |
1da177e4 LT |
92 | |
93 | if (last_channels != channels) { | |
94 | union i2c_smbus_data mplxdata; | |
95 | mplxdata.byte = channels; | |
96 | ||
97 | error = amd756_smbus.algo->smbus_xfer(adap, 0x18, 0, | |
98 | I2C_SMBUS_WRITE, 0x01, | |
99 | I2C_SMBUS_BYTE_DATA, | |
100 | &mplxdata); | |
101 | if (error) | |
102 | goto UNLOCK; | |
103 | last_channels = channels; | |
104 | } | |
105 | error = amd756_smbus.algo->smbus_xfer(adap, addr, flags, read_write, | |
106 | command, size, data); | |
107 | ||
108 | UNLOCK: | |
5c085d36 | 109 | mutex_unlock(&amd756_lock); |
1da177e4 LT |
110 | return error; |
111 | } | |
112 | ||
113 | static s32 amd756_access_virt1(struct i2c_adapter * adap, u16 addr, | |
114 | unsigned short flags, char read_write, | |
115 | u8 command, int size, | |
116 | union i2c_smbus_data * data) | |
117 | { | |
118 | /* CPU0: channels 1 and 0 enabled */ | |
119 | return amd756_access_channel(adap, addr, flags, read_write, command, | |
120 | size, data, 0x03); | |
121 | } | |
122 | ||
123 | static s32 amd756_access_virt2(struct i2c_adapter * adap, u16 addr, | |
124 | unsigned short flags, char read_write, | |
125 | u8 command, int size, | |
126 | union i2c_smbus_data * data) | |
127 | { | |
128 | /* CPU1: channels 2 and 5 enabled */ | |
129 | return amd756_access_channel(adap, addr, flags, read_write, command, | |
130 | size, data, 0x24); | |
131 | } | |
132 | ||
133 | static s32 amd756_access_virt3(struct i2c_adapter * adap, u16 addr, | |
134 | unsigned short flags, char read_write, | |
135 | u8 command, int size, | |
136 | union i2c_smbus_data * data) | |
137 | { | |
138 | /* CPU2: channels 3 and 6 enabled */ | |
139 | return amd756_access_channel(adap, addr, flags, read_write, command, | |
140 | size, data, 0x48); | |
141 | } | |
142 | ||
143 | static s32 amd756_access_virt4(struct i2c_adapter * adap, u16 addr, | |
144 | unsigned short flags, char read_write, | |
145 | u8 command, int size, | |
146 | union i2c_smbus_data * data) | |
147 | { | |
148 | /* CPU3: channels 4 and 7 enabled */ | |
149 | return amd756_access_channel(adap, addr, flags, read_write, command, | |
150 | size, data, 0x90); | |
151 | } | |
152 | ||
153 | static int __init amd756_s4882_init(void) | |
154 | { | |
155 | int i, error; | |
156 | union i2c_smbus_data ioconfig; | |
157 | ||
bd4bc3db JD |
158 | /* Configure the PCA9556 multiplexer */ |
159 | ioconfig.byte = 0x00; /* All I/O to output mode */ | |
160 | error = i2c_smbus_xfer(&amd756_smbus, 0x18, 0, I2C_SMBUS_WRITE, 0x03, | |
161 | I2C_SMBUS_BYTE_DATA, &ioconfig); | |
162 | if (error) { | |
163 | dev_err(&amd756_smbus.dev, "PCA9556 configuration failed\n"); | |
164 | error = -EIO; | |
165 | goto ERROR0; | |
166 | } | |
167 | ||
1da177e4 LT |
168 | /* Unregister physical bus */ |
169 | error = i2c_del_adapter(&amd756_smbus); | |
170 | if (error) { | |
171 | if (error == -EINVAL) | |
172 | error = -ENODEV; | |
173 | else | |
174 | dev_err(&amd756_smbus.dev, "Physical bus removal " | |
175 | "failed\n"); | |
176 | goto ERROR0; | |
177 | } | |
178 | ||
179 | printk(KERN_INFO "Enabling SMBus multiplexing for Tyan S4882\n"); | |
1da177e4 | 180 | /* Define the 5 virtual adapters and algorithms structures */ |
deb875c7 | 181 | if (!(s4882_adapter = kzalloc(5 * sizeof(struct i2c_adapter), |
1da177e4 LT |
182 | GFP_KERNEL))) { |
183 | error = -ENOMEM; | |
184 | goto ERROR1; | |
185 | } | |
deb875c7 | 186 | if (!(s4882_algo = kzalloc(5 * sizeof(struct i2c_algorithm), |
1da177e4 LT |
187 | GFP_KERNEL))) { |
188 | error = -ENOMEM; | |
189 | goto ERROR2; | |
190 | } | |
191 | ||
192 | /* Fill in the new structures */ | |
193 | s4882_algo[0] = *(amd756_smbus.algo); | |
194 | s4882_algo[0].smbus_xfer = amd756_access_virt0; | |
195 | s4882_adapter[0] = amd756_smbus; | |
196 | s4882_adapter[0].algo = s4882_algo; | |
12a917f6 | 197 | s4882_adapter[0].dev.parent = amd756_smbus.dev.parent; |
1da177e4 LT |
198 | for (i = 1; i < 5; i++) { |
199 | s4882_algo[i] = *(amd756_smbus.algo); | |
200 | s4882_adapter[i] = amd756_smbus; | |
201 | sprintf(s4882_adapter[i].name, | |
202 | "SMBus 8111 adapter (CPU%d)", i-1); | |
203 | s4882_adapter[i].algo = s4882_algo+i; | |
12a917f6 | 204 | s4882_adapter[i].dev.parent = amd756_smbus.dev.parent; |
1da177e4 LT |
205 | } |
206 | s4882_algo[1].smbus_xfer = amd756_access_virt1; | |
207 | s4882_algo[2].smbus_xfer = amd756_access_virt2; | |
208 | s4882_algo[3].smbus_xfer = amd756_access_virt3; | |
209 | s4882_algo[4].smbus_xfer = amd756_access_virt4; | |
210 | ||
1da177e4 LT |
211 | /* Register virtual adapters */ |
212 | for (i = 0; i < 5; i++) { | |
213 | error = i2c_add_adapter(s4882_adapter+i); | |
214 | if (error) { | |
bd4bc3db | 215 | printk(KERN_ERR "i2c-amd756-s4882: " |
1da177e4 LT |
216 | "Virtual adapter %d registration " |
217 | "failed, module not inserted\n", i); | |
218 | for (i--; i >= 0; i--) | |
219 | i2c_del_adapter(s4882_adapter+i); | |
220 | goto ERROR3; | |
221 | } | |
222 | } | |
223 | ||
224 | return 0; | |
225 | ||
226 | ERROR3: | |
227 | kfree(s4882_algo); | |
228 | s4882_algo = NULL; | |
229 | ERROR2: | |
230 | kfree(s4882_adapter); | |
231 | s4882_adapter = NULL; | |
232 | ERROR1: | |
ee56d977 JD |
233 | /* Restore physical bus */ |
234 | i2c_add_adapter(&amd756_smbus); | |
1da177e4 LT |
235 | ERROR0: |
236 | return error; | |
237 | } | |
238 | ||
239 | static void __exit amd756_s4882_exit(void) | |
240 | { | |
241 | if (s4882_adapter) { | |
242 | int i; | |
243 | ||
244 | for (i = 0; i < 5; i++) | |
245 | i2c_del_adapter(s4882_adapter+i); | |
246 | kfree(s4882_adapter); | |
247 | s4882_adapter = NULL; | |
248 | } | |
6044ec88 JJ |
249 | kfree(s4882_algo); |
250 | s4882_algo = NULL; | |
1da177e4 LT |
251 | |
252 | /* Restore physical bus */ | |
253 | if (i2c_add_adapter(&amd756_smbus)) | |
bd4bc3db JD |
254 | printk(KERN_ERR "i2c-amd756-s4882: " |
255 | "Physical bus restoration failed\n"); | |
1da177e4 LT |
256 | } |
257 | ||
258 | MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>"); | |
259 | MODULE_DESCRIPTION("S4882 SMBus multiplexing"); | |
260 | MODULE_LICENSE("GPL"); | |
261 | ||
262 | module_init(amd756_s4882_init); | |
263 | module_exit(amd756_s4882_exit); |