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1da177e4 LT |
1 | /* |
2 | * i2c-amd756-s4882.c - i2c-amd756 extras for the Tyan S4882 motherboard | |
3 | * | |
7c81c60f | 4 | * Copyright (C) 2004, 2008 Jean Delvare <jdelvare@suse.de> |
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. | |
1da177e4 LT |
15 | */ |
16 | ||
17 | /* | |
18 | * We select the channels by sending commands to the Philips | |
19 | * PCA9556 chip at I2C address 0x18. The main adapter is used for | |
20 | * the non-multiplexed part of the bus, and 4 virtual adapters | |
21 | * are defined for the multiplexed addresses: 0x50-0x53 (memory | |
22 | * module EEPROM) located on channels 1-4, and 0x4c (LM63) | |
23 | * located on multiplexed channels 0 and 5-7. We define one | |
24 | * virtual adapter per CPU, which corresponds to two multiplexed | |
25 | * channels: | |
26 | * CPU0: virtual adapter 1, channels 1 and 0 | |
27 | * CPU1: virtual adapter 2, channels 2 and 5 | |
28 | * CPU2: virtual adapter 3, channels 3 and 6 | |
29 | * CPU3: virtual adapter 4, channels 4 and 7 | |
30 | */ | |
31 | ||
32 | #include <linux/module.h> | |
33 | #include <linux/kernel.h> | |
34 | #include <linux/slab.h> | |
35 | #include <linux/init.h> | |
36 | #include <linux/i2c.h> | |
5c085d36 | 37 | #include <linux/mutex.h> |
1da177e4 LT |
38 | |
39 | extern struct i2c_adapter amd756_smbus; | |
40 | ||
41 | static struct i2c_adapter *s4882_adapter; | |
42 | static struct i2c_algorithm *s4882_algo; | |
43 | ||
44 | /* Wrapper access functions for multiplexed SMBus */ | |
d7d2fe38 | 45 | static DEFINE_MUTEX(amd756_lock); |
1da177e4 LT |
46 | |
47 | static s32 amd756_access_virt0(struct i2c_adapter * adap, u16 addr, | |
48 | unsigned short flags, char read_write, | |
49 | u8 command, int size, | |
50 | union i2c_smbus_data * data) | |
51 | { | |
52 | int error; | |
53 | ||
54 | /* We exclude the multiplexed addresses */ | |
55 | if (addr == 0x4c || (addr & 0xfc) == 0x50 || (addr & 0xfc) == 0x30 | |
56 | || addr == 0x18) | |
97140342 | 57 | return -ENXIO; |
1da177e4 | 58 | |
5c085d36 | 59 | mutex_lock(&amd756_lock); |
1da177e4 LT |
60 | |
61 | error = amd756_smbus.algo->smbus_xfer(adap, addr, flags, read_write, | |
62 | command, size, data); | |
63 | ||
5c085d36 | 64 | mutex_unlock(&amd756_lock); |
1da177e4 LT |
65 | |
66 | return error; | |
67 | } | |
68 | ||
69 | /* We remember the last used channels combination so as to only switch | |
70 | channels when it is really needed. This greatly reduces the SMBus | |
71 | overhead, but also assumes that nobody will be writing to the PCA9556 | |
72 | in our back. */ | |
73 | static u8 last_channels; | |
74 | ||
75 | static inline s32 amd756_access_channel(struct i2c_adapter * adap, u16 addr, | |
76 | unsigned short flags, char read_write, | |
77 | u8 command, int size, | |
78 | union i2c_smbus_data * data, | |
79 | u8 channels) | |
80 | { | |
81 | int error; | |
82 | ||
83 | /* We exclude the non-multiplexed addresses */ | |
84 | if (addr != 0x4c && (addr & 0xfc) != 0x50 && (addr & 0xfc) != 0x30) | |
97140342 | 85 | return -ENXIO; |
1da177e4 | 86 | |
5c085d36 | 87 | mutex_lock(&amd756_lock); |
1da177e4 LT |
88 | |
89 | if (last_channels != channels) { | |
90 | union i2c_smbus_data mplxdata; | |
91 | mplxdata.byte = channels; | |
92 | ||
93 | error = amd756_smbus.algo->smbus_xfer(adap, 0x18, 0, | |
94 | I2C_SMBUS_WRITE, 0x01, | |
95 | I2C_SMBUS_BYTE_DATA, | |
96 | &mplxdata); | |
97 | if (error) | |
98 | goto UNLOCK; | |
99 | last_channels = channels; | |
100 | } | |
101 | error = amd756_smbus.algo->smbus_xfer(adap, addr, flags, read_write, | |
102 | command, size, data); | |
103 | ||
104 | UNLOCK: | |
5c085d36 | 105 | mutex_unlock(&amd756_lock); |
1da177e4 LT |
106 | return error; |
107 | } | |
108 | ||
109 | static s32 amd756_access_virt1(struct i2c_adapter * adap, u16 addr, | |
110 | unsigned short flags, char read_write, | |
111 | u8 command, int size, | |
112 | union i2c_smbus_data * data) | |
113 | { | |
114 | /* CPU0: channels 1 and 0 enabled */ | |
115 | return amd756_access_channel(adap, addr, flags, read_write, command, | |
116 | size, data, 0x03); | |
117 | } | |
118 | ||
119 | static s32 amd756_access_virt2(struct i2c_adapter * adap, u16 addr, | |
120 | unsigned short flags, char read_write, | |
121 | u8 command, int size, | |
122 | union i2c_smbus_data * data) | |
123 | { | |
124 | /* CPU1: channels 2 and 5 enabled */ | |
125 | return amd756_access_channel(adap, addr, flags, read_write, command, | |
126 | size, data, 0x24); | |
127 | } | |
128 | ||
129 | static s32 amd756_access_virt3(struct i2c_adapter * adap, u16 addr, | |
130 | unsigned short flags, char read_write, | |
131 | u8 command, int size, | |
132 | union i2c_smbus_data * data) | |
133 | { | |
134 | /* CPU2: channels 3 and 6 enabled */ | |
135 | return amd756_access_channel(adap, addr, flags, read_write, command, | |
136 | size, data, 0x48); | |
137 | } | |
138 | ||
139 | static s32 amd756_access_virt4(struct i2c_adapter * adap, u16 addr, | |
140 | unsigned short flags, char read_write, | |
141 | u8 command, int size, | |
142 | union i2c_smbus_data * data) | |
143 | { | |
144 | /* CPU3: channels 4 and 7 enabled */ | |
145 | return amd756_access_channel(adap, addr, flags, read_write, command, | |
146 | size, data, 0x90); | |
147 | } | |
148 | ||
149 | static int __init amd756_s4882_init(void) | |
150 | { | |
151 | int i, error; | |
152 | union i2c_smbus_data ioconfig; | |
153 | ||
399d6b26 JD |
154 | if (!amd756_smbus.dev.parent) |
155 | return -ENODEV; | |
156 | ||
bd4bc3db JD |
157 | /* Configure the PCA9556 multiplexer */ |
158 | ioconfig.byte = 0x00; /* All I/O to output mode */ | |
159 | error = i2c_smbus_xfer(&amd756_smbus, 0x18, 0, I2C_SMBUS_WRITE, 0x03, | |
160 | I2C_SMBUS_BYTE_DATA, &ioconfig); | |
161 | if (error) { | |
162 | dev_err(&amd756_smbus.dev, "PCA9556 configuration failed\n"); | |
163 | error = -EIO; | |
164 | goto ERROR0; | |
165 | } | |
166 | ||
1da177e4 | 167 | /* Unregister physical bus */ |
bf51a8c5 | 168 | i2c_del_adapter(&amd756_smbus); |
1da177e4 LT |
169 | |
170 | printk(KERN_INFO "Enabling SMBus multiplexing for Tyan S4882\n"); | |
1da177e4 | 171 | /* Define the 5 virtual adapters and algorithms structures */ |
deb875c7 | 172 | if (!(s4882_adapter = kzalloc(5 * sizeof(struct i2c_adapter), |
1da177e4 LT |
173 | GFP_KERNEL))) { |
174 | error = -ENOMEM; | |
175 | goto ERROR1; | |
176 | } | |
deb875c7 | 177 | if (!(s4882_algo = kzalloc(5 * sizeof(struct i2c_algorithm), |
1da177e4 LT |
178 | GFP_KERNEL))) { |
179 | error = -ENOMEM; | |
180 | goto ERROR2; | |
181 | } | |
182 | ||
183 | /* Fill in the new structures */ | |
184 | s4882_algo[0] = *(amd756_smbus.algo); | |
185 | s4882_algo[0].smbus_xfer = amd756_access_virt0; | |
186 | s4882_adapter[0] = amd756_smbus; | |
187 | s4882_adapter[0].algo = s4882_algo; | |
12a917f6 | 188 | s4882_adapter[0].dev.parent = amd756_smbus.dev.parent; |
1da177e4 LT |
189 | for (i = 1; i < 5; i++) { |
190 | s4882_algo[i] = *(amd756_smbus.algo); | |
191 | s4882_adapter[i] = amd756_smbus; | |
66c7acf6 JD |
192 | snprintf(s4882_adapter[i].name, sizeof(s4882_adapter[i].name), |
193 | "SMBus 8111 adapter (CPU%d)", i-1); | |
1da177e4 | 194 | s4882_adapter[i].algo = s4882_algo+i; |
12a917f6 | 195 | s4882_adapter[i].dev.parent = amd756_smbus.dev.parent; |
1da177e4 LT |
196 | } |
197 | s4882_algo[1].smbus_xfer = amd756_access_virt1; | |
198 | s4882_algo[2].smbus_xfer = amd756_access_virt2; | |
199 | s4882_algo[3].smbus_xfer = amd756_access_virt3; | |
200 | s4882_algo[4].smbus_xfer = amd756_access_virt4; | |
201 | ||
1da177e4 LT |
202 | /* Register virtual adapters */ |
203 | for (i = 0; i < 5; i++) { | |
204 | error = i2c_add_adapter(s4882_adapter+i); | |
205 | if (error) { | |
bd4bc3db | 206 | printk(KERN_ERR "i2c-amd756-s4882: " |
1da177e4 LT |
207 | "Virtual adapter %d registration " |
208 | "failed, module not inserted\n", i); | |
209 | for (i--; i >= 0; i--) | |
210 | i2c_del_adapter(s4882_adapter+i); | |
211 | goto ERROR3; | |
212 | } | |
213 | } | |
214 | ||
215 | return 0; | |
216 | ||
217 | ERROR3: | |
218 | kfree(s4882_algo); | |
219 | s4882_algo = NULL; | |
220 | ERROR2: | |
221 | kfree(s4882_adapter); | |
222 | s4882_adapter = NULL; | |
223 | ERROR1: | |
ee56d977 JD |
224 | /* Restore physical bus */ |
225 | i2c_add_adapter(&amd756_smbus); | |
1da177e4 LT |
226 | ERROR0: |
227 | return error; | |
228 | } | |
229 | ||
230 | static void __exit amd756_s4882_exit(void) | |
231 | { | |
232 | if (s4882_adapter) { | |
233 | int i; | |
234 | ||
235 | for (i = 0; i < 5; i++) | |
236 | i2c_del_adapter(s4882_adapter+i); | |
237 | kfree(s4882_adapter); | |
238 | s4882_adapter = NULL; | |
239 | } | |
6044ec88 JJ |
240 | kfree(s4882_algo); |
241 | s4882_algo = NULL; | |
1da177e4 LT |
242 | |
243 | /* Restore physical bus */ | |
244 | if (i2c_add_adapter(&amd756_smbus)) | |
bd4bc3db JD |
245 | printk(KERN_ERR "i2c-amd756-s4882: " |
246 | "Physical bus restoration failed\n"); | |
1da177e4 LT |
247 | } |
248 | ||
7c81c60f | 249 | MODULE_AUTHOR("Jean Delvare <jdelvare@suse.de>"); |
1da177e4 LT |
250 | MODULE_DESCRIPTION("S4882 SMBus multiplexing"); |
251 | MODULE_LICENSE("GPL"); | |
252 | ||
253 | module_init(amd756_s4882_init); | |
254 | module_exit(amd756_s4882_exit); |