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1da177e4 LT |
1 | /* |
2 | * i2c-amd756-s4882.c - i2c-amd756 extras for the Tyan S4882 motherboard | |
3 | * | |
4 | * Copyright (C) 2004 Jean Delvare <khali@linux-fr.org> | |
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> | |
41 | ||
42 | extern struct i2c_adapter amd756_smbus; | |
43 | ||
44 | static struct i2c_adapter *s4882_adapter; | |
45 | static struct i2c_algorithm *s4882_algo; | |
46 | ||
47 | /* Wrapper access functions for multiplexed SMBus */ | |
48 | static struct semaphore amd756_lock; | |
49 | ||
50 | static s32 amd756_access_virt0(struct i2c_adapter * adap, u16 addr, | |
51 | unsigned short flags, char read_write, | |
52 | u8 command, int size, | |
53 | union i2c_smbus_data * data) | |
54 | { | |
55 | int error; | |
56 | ||
57 | /* We exclude the multiplexed addresses */ | |
58 | if (addr == 0x4c || (addr & 0xfc) == 0x50 || (addr & 0xfc) == 0x30 | |
59 | || addr == 0x18) | |
60 | return -1; | |
61 | ||
62 | down(&amd756_lock); | |
63 | ||
64 | error = amd756_smbus.algo->smbus_xfer(adap, addr, flags, read_write, | |
65 | command, size, data); | |
66 | ||
67 | up(&amd756_lock); | |
68 | ||
69 | return error; | |
70 | } | |
71 | ||
72 | /* We remember the last used channels combination so as to only switch | |
73 | channels when it is really needed. This greatly reduces the SMBus | |
74 | overhead, but also assumes that nobody will be writing to the PCA9556 | |
75 | in our back. */ | |
76 | static u8 last_channels; | |
77 | ||
78 | static inline s32 amd756_access_channel(struct i2c_adapter * adap, u16 addr, | |
79 | unsigned short flags, char read_write, | |
80 | u8 command, int size, | |
81 | union i2c_smbus_data * data, | |
82 | u8 channels) | |
83 | { | |
84 | int error; | |
85 | ||
86 | /* We exclude the non-multiplexed addresses */ | |
87 | if (addr != 0x4c && (addr & 0xfc) != 0x50 && (addr & 0xfc) != 0x30) | |
88 | return -1; | |
89 | ||
90 | down(&amd756_lock); | |
91 | ||
92 | if (last_channels != channels) { | |
93 | union i2c_smbus_data mplxdata; | |
94 | mplxdata.byte = channels; | |
95 | ||
96 | error = amd756_smbus.algo->smbus_xfer(adap, 0x18, 0, | |
97 | I2C_SMBUS_WRITE, 0x01, | |
98 | I2C_SMBUS_BYTE_DATA, | |
99 | &mplxdata); | |
100 | if (error) | |
101 | goto UNLOCK; | |
102 | last_channels = channels; | |
103 | } | |
104 | error = amd756_smbus.algo->smbus_xfer(adap, addr, flags, read_write, | |
105 | command, size, data); | |
106 | ||
107 | UNLOCK: | |
108 | up(&amd756_lock); | |
109 | return error; | |
110 | } | |
111 | ||
112 | static s32 amd756_access_virt1(struct i2c_adapter * adap, u16 addr, | |
113 | unsigned short flags, char read_write, | |
114 | u8 command, int size, | |
115 | union i2c_smbus_data * data) | |
116 | { | |
117 | /* CPU0: channels 1 and 0 enabled */ | |
118 | return amd756_access_channel(adap, addr, flags, read_write, command, | |
119 | size, data, 0x03); | |
120 | } | |
121 | ||
122 | static s32 amd756_access_virt2(struct i2c_adapter * adap, u16 addr, | |
123 | unsigned short flags, char read_write, | |
124 | u8 command, int size, | |
125 | union i2c_smbus_data * data) | |
126 | { | |
127 | /* CPU1: channels 2 and 5 enabled */ | |
128 | return amd756_access_channel(adap, addr, flags, read_write, command, | |
129 | size, data, 0x24); | |
130 | } | |
131 | ||
132 | static s32 amd756_access_virt3(struct i2c_adapter * adap, u16 addr, | |
133 | unsigned short flags, char read_write, | |
134 | u8 command, int size, | |
135 | union i2c_smbus_data * data) | |
136 | { | |
137 | /* CPU2: channels 3 and 6 enabled */ | |
138 | return amd756_access_channel(adap, addr, flags, read_write, command, | |
139 | size, data, 0x48); | |
140 | } | |
141 | ||
142 | static s32 amd756_access_virt4(struct i2c_adapter * adap, u16 addr, | |
143 | unsigned short flags, char read_write, | |
144 | u8 command, int size, | |
145 | union i2c_smbus_data * data) | |
146 | { | |
147 | /* CPU3: channels 4 and 7 enabled */ | |
148 | return amd756_access_channel(adap, addr, flags, read_write, command, | |
149 | size, data, 0x90); | |
150 | } | |
151 | ||
152 | static int __init amd756_s4882_init(void) | |
153 | { | |
154 | int i, error; | |
155 | union i2c_smbus_data ioconfig; | |
156 | ||
157 | /* Unregister physical bus */ | |
158 | error = i2c_del_adapter(&amd756_smbus); | |
159 | if (error) { | |
160 | if (error == -EINVAL) | |
161 | error = -ENODEV; | |
162 | else | |
163 | dev_err(&amd756_smbus.dev, "Physical bus removal " | |
164 | "failed\n"); | |
165 | goto ERROR0; | |
166 | } | |
167 | ||
168 | printk(KERN_INFO "Enabling SMBus multiplexing for Tyan S4882\n"); | |
169 | init_MUTEX(&amd756_lock); | |
170 | ||
171 | /* Define the 5 virtual adapters and algorithms structures */ | |
172 | if (!(s4882_adapter = kmalloc(5 * sizeof(struct i2c_adapter), | |
173 | GFP_KERNEL))) { | |
174 | error = -ENOMEM; | |
175 | goto ERROR1; | |
176 | } | |
177 | if (!(s4882_algo = kmalloc(5 * sizeof(struct i2c_algorithm), | |
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; | |
188 | for (i = 1; i < 5; i++) { | |
189 | s4882_algo[i] = *(amd756_smbus.algo); | |
190 | s4882_adapter[i] = amd756_smbus; | |
191 | sprintf(s4882_adapter[i].name, | |
192 | "SMBus 8111 adapter (CPU%d)", i-1); | |
193 | s4882_adapter[i].algo = s4882_algo+i; | |
194 | } | |
195 | s4882_algo[1].smbus_xfer = amd756_access_virt1; | |
196 | s4882_algo[2].smbus_xfer = amd756_access_virt2; | |
197 | s4882_algo[3].smbus_xfer = amd756_access_virt3; | |
198 | s4882_algo[4].smbus_xfer = amd756_access_virt4; | |
199 | ||
200 | /* Configure the PCA9556 multiplexer */ | |
201 | ioconfig.byte = 0x00; /* All I/O to output mode */ | |
202 | error = amd756_smbus.algo->smbus_xfer(&amd756_smbus, 0x18, 0, | |
203 | I2C_SMBUS_WRITE, 0x03, | |
204 | I2C_SMBUS_BYTE_DATA, &ioconfig); | |
205 | if (error) { | |
206 | dev_err(&amd756_smbus.dev, "PCA9556 configuration failed\n"); | |
207 | error = -EIO; | |
208 | goto ERROR3; | |
209 | } | |
210 | ||
211 | /* Register virtual adapters */ | |
212 | for (i = 0; i < 5; i++) { | |
213 | error = i2c_add_adapter(s4882_adapter+i); | |
214 | if (error) { | |
215 | dev_err(&amd756_smbus.dev, | |
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: | |
233 | i2c_del_adapter(&amd756_smbus); | |
234 | ERROR0: | |
235 | return error; | |
236 | } | |
237 | ||
238 | static void __exit amd756_s4882_exit(void) | |
239 | { | |
240 | if (s4882_adapter) { | |
241 | int i; | |
242 | ||
243 | for (i = 0; i < 5; i++) | |
244 | i2c_del_adapter(s4882_adapter+i); | |
245 | kfree(s4882_adapter); | |
246 | s4882_adapter = NULL; | |
247 | } | |
248 | if (s4882_algo) { | |
249 | kfree(s4882_algo); | |
250 | s4882_algo = NULL; | |
251 | } | |
252 | ||
253 | /* Restore physical bus */ | |
254 | if (i2c_add_adapter(&amd756_smbus)) | |
255 | dev_err(&amd756_smbus.dev, "Physical bus restoration " | |
256 | "failed\n"); | |
257 | } | |
258 | ||
259 | MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>"); | |
260 | MODULE_DESCRIPTION("S4882 SMBus multiplexing"); | |
261 | MODULE_LICENSE("GPL"); | |
262 | ||
263 | module_init(amd756_s4882_init); | |
264 | module_exit(amd756_s4882_exit); |