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279e9024 JD |
1 | /* |
2 | * i2c-nforce2-s4985.c - i2c-nforce2 extras for the Tyan S4985 motherboard | |
3 | * | |
7c81c60f | 4 | * Copyright (C) 2008 Jean Delvare <jdelvare@suse.de> |
279e9024 JD |
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. | |
279e9024 JD |
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. We define one virtual | |
23 | * adapter per CPU, which corresponds to one multiplexed channel: | |
24 | * CPU0: virtual adapter 1, channel 1 | |
25 | * CPU1: virtual adapter 2, channel 2 | |
26 | * CPU2: virtual adapter 3, channel 3 | |
27 | * CPU3: virtual adapter 4, channel 4 | |
28 | */ | |
29 | ||
30 | #include <linux/module.h> | |
31 | #include <linux/kernel.h> | |
32 | #include <linux/slab.h> | |
33 | #include <linux/init.h> | |
34 | #include <linux/i2c.h> | |
35 | #include <linux/mutex.h> | |
36 | ||
37 | extern struct i2c_adapter *nforce2_smbus; | |
38 | ||
39 | static struct i2c_adapter *s4985_adapter; | |
40 | static struct i2c_algorithm *s4985_algo; | |
41 | ||
42 | /* Wrapper access functions for multiplexed SMBus */ | |
43 | static DEFINE_MUTEX(nforce2_lock); | |
44 | ||
45 | static s32 nforce2_access_virt0(struct i2c_adapter *adap, u16 addr, | |
46 | unsigned short flags, char read_write, | |
47 | u8 command, int size, | |
48 | union i2c_smbus_data *data) | |
49 | { | |
50 | int error; | |
51 | ||
52 | /* We exclude the multiplexed addresses */ | |
53 | if ((addr & 0xfc) == 0x50 || (addr & 0xfc) == 0x30 | |
54 | || addr == 0x18) | |
55 | return -ENXIO; | |
56 | ||
57 | mutex_lock(&nforce2_lock); | |
58 | error = nforce2_smbus->algo->smbus_xfer(adap, addr, flags, read_write, | |
59 | command, size, data); | |
60 | mutex_unlock(&nforce2_lock); | |
61 | ||
62 | return error; | |
63 | } | |
64 | ||
65 | /* We remember the last used channels combination so as to only switch | |
66 | channels when it is really needed. This greatly reduces the SMBus | |
67 | overhead, but also assumes that nobody will be writing to the PCA9556 | |
68 | in our back. */ | |
69 | static u8 last_channels; | |
70 | ||
71 | static inline s32 nforce2_access_channel(struct i2c_adapter *adap, u16 addr, | |
72 | unsigned short flags, char read_write, | |
73 | u8 command, int size, | |
74 | union i2c_smbus_data *data, | |
75 | u8 channels) | |
76 | { | |
77 | int error; | |
78 | ||
79 | /* We exclude the non-multiplexed addresses */ | |
80 | if ((addr & 0xfc) != 0x50 && (addr & 0xfc) != 0x30) | |
81 | return -ENXIO; | |
82 | ||
83 | mutex_lock(&nforce2_lock); | |
84 | if (last_channels != channels) { | |
85 | union i2c_smbus_data mplxdata; | |
86 | mplxdata.byte = channels; | |
87 | ||
88 | error = nforce2_smbus->algo->smbus_xfer(adap, 0x18, 0, | |
89 | I2C_SMBUS_WRITE, 0x01, | |
90 | I2C_SMBUS_BYTE_DATA, | |
91 | &mplxdata); | |
92 | if (error) | |
93 | goto UNLOCK; | |
94 | last_channels = channels; | |
95 | } | |
96 | error = nforce2_smbus->algo->smbus_xfer(adap, addr, flags, read_write, | |
97 | command, size, data); | |
98 | ||
99 | UNLOCK: | |
100 | mutex_unlock(&nforce2_lock); | |
101 | return error; | |
102 | } | |
103 | ||
104 | static s32 nforce2_access_virt1(struct i2c_adapter *adap, u16 addr, | |
105 | unsigned short flags, char read_write, | |
106 | u8 command, int size, | |
107 | union i2c_smbus_data *data) | |
108 | { | |
109 | /* CPU0: channel 1 enabled */ | |
110 | return nforce2_access_channel(adap, addr, flags, read_write, command, | |
111 | size, data, 0x02); | |
112 | } | |
113 | ||
114 | static s32 nforce2_access_virt2(struct i2c_adapter *adap, u16 addr, | |
115 | unsigned short flags, char read_write, | |
116 | u8 command, int size, | |
117 | union i2c_smbus_data *data) | |
118 | { | |
119 | /* CPU1: channel 2 enabled */ | |
120 | return nforce2_access_channel(adap, addr, flags, read_write, command, | |
121 | size, data, 0x04); | |
122 | } | |
123 | ||
124 | static s32 nforce2_access_virt3(struct i2c_adapter *adap, u16 addr, | |
125 | unsigned short flags, char read_write, | |
126 | u8 command, int size, | |
127 | union i2c_smbus_data *data) | |
128 | { | |
129 | /* CPU2: channel 3 enabled */ | |
130 | return nforce2_access_channel(adap, addr, flags, read_write, command, | |
131 | size, data, 0x08); | |
132 | } | |
133 | ||
134 | static s32 nforce2_access_virt4(struct i2c_adapter *adap, u16 addr, | |
135 | unsigned short flags, char read_write, | |
136 | u8 command, int size, | |
137 | union i2c_smbus_data *data) | |
138 | { | |
139 | /* CPU3: channel 4 enabled */ | |
140 | return nforce2_access_channel(adap, addr, flags, read_write, command, | |
141 | size, data, 0x10); | |
142 | } | |
143 | ||
144 | static int __init nforce2_s4985_init(void) | |
145 | { | |
146 | int i, error; | |
147 | union i2c_smbus_data ioconfig; | |
148 | ||
399d6b26 JD |
149 | if (!nforce2_smbus) |
150 | return -ENODEV; | |
151 | ||
bd4bc3db JD |
152 | /* Configure the PCA9556 multiplexer */ |
153 | ioconfig.byte = 0x00; /* All I/O to output mode */ | |
154 | error = i2c_smbus_xfer(nforce2_smbus, 0x18, 0, I2C_SMBUS_WRITE, 0x03, | |
155 | I2C_SMBUS_BYTE_DATA, &ioconfig); | |
156 | if (error) { | |
157 | dev_err(&nforce2_smbus->dev, "PCA9556 configuration failed\n"); | |
158 | error = -EIO; | |
159 | goto ERROR0; | |
160 | } | |
161 | ||
279e9024 | 162 | /* Unregister physical bus */ |
bf51a8c5 | 163 | i2c_del_adapter(nforce2_smbus); |
279e9024 JD |
164 | |
165 | printk(KERN_INFO "Enabling SMBus multiplexing for Tyan S4985\n"); | |
166 | /* Define the 5 virtual adapters and algorithms structures */ | |
167 | s4985_adapter = kzalloc(5 * sizeof(struct i2c_adapter), GFP_KERNEL); | |
168 | if (!s4985_adapter) { | |
169 | error = -ENOMEM; | |
170 | goto ERROR1; | |
171 | } | |
172 | s4985_algo = kzalloc(5 * sizeof(struct i2c_algorithm), GFP_KERNEL); | |
173 | if (!s4985_algo) { | |
174 | error = -ENOMEM; | |
175 | goto ERROR2; | |
176 | } | |
177 | ||
178 | /* Fill in the new structures */ | |
179 | s4985_algo[0] = *(nforce2_smbus->algo); | |
180 | s4985_algo[0].smbus_xfer = nforce2_access_virt0; | |
181 | s4985_adapter[0] = *nforce2_smbus; | |
182 | s4985_adapter[0].algo = s4985_algo; | |
183 | s4985_adapter[0].dev.parent = nforce2_smbus->dev.parent; | |
184 | for (i = 1; i < 5; i++) { | |
185 | s4985_algo[i] = *(nforce2_smbus->algo); | |
186 | s4985_adapter[i] = *nforce2_smbus; | |
187 | snprintf(s4985_adapter[i].name, sizeof(s4985_adapter[i].name), | |
188 | "SMBus nForce2 adapter (CPU%d)", i - 1); | |
189 | s4985_adapter[i].algo = s4985_algo + i; | |
190 | s4985_adapter[i].dev.parent = nforce2_smbus->dev.parent; | |
191 | } | |
192 | s4985_algo[1].smbus_xfer = nforce2_access_virt1; | |
193 | s4985_algo[2].smbus_xfer = nforce2_access_virt2; | |
194 | s4985_algo[3].smbus_xfer = nforce2_access_virt3; | |
195 | s4985_algo[4].smbus_xfer = nforce2_access_virt4; | |
196 | ||
279e9024 JD |
197 | /* Register virtual adapters */ |
198 | for (i = 0; i < 5; i++) { | |
199 | error = i2c_add_adapter(s4985_adapter + i); | |
200 | if (error) { | |
bd4bc3db JD |
201 | printk(KERN_ERR "i2c-nforce2-s4985: " |
202 | "Virtual adapter %d registration " | |
203 | "failed, module not inserted\n", i); | |
279e9024 JD |
204 | for (i--; i >= 0; i--) |
205 | i2c_del_adapter(s4985_adapter + i); | |
206 | goto ERROR3; | |
207 | } | |
208 | } | |
209 | ||
210 | return 0; | |
211 | ||
212 | ERROR3: | |
213 | kfree(s4985_algo); | |
214 | s4985_algo = NULL; | |
215 | ERROR2: | |
216 | kfree(s4985_adapter); | |
217 | s4985_adapter = NULL; | |
218 | ERROR1: | |
219 | /* Restore physical bus */ | |
220 | i2c_add_adapter(nforce2_smbus); | |
221 | ERROR0: | |
222 | return error; | |
223 | } | |
224 | ||
225 | static void __exit nforce2_s4985_exit(void) | |
226 | { | |
227 | if (s4985_adapter) { | |
228 | int i; | |
229 | ||
230 | for (i = 0; i < 5; i++) | |
231 | i2c_del_adapter(s4985_adapter+i); | |
232 | kfree(s4985_adapter); | |
233 | s4985_adapter = NULL; | |
234 | } | |
235 | kfree(s4985_algo); | |
236 | s4985_algo = NULL; | |
237 | ||
238 | /* Restore physical bus */ | |
239 | if (i2c_add_adapter(nforce2_smbus)) | |
bd4bc3db JD |
240 | printk(KERN_ERR "i2c-nforce2-s4985: " |
241 | "Physical bus restoration failed\n"); | |
279e9024 JD |
242 | } |
243 | ||
7c81c60f | 244 | MODULE_AUTHOR("Jean Delvare <jdelvare@suse.de>"); |
279e9024 JD |
245 | MODULE_DESCRIPTION("S4985 SMBus multiplexing"); |
246 | MODULE_LICENSE("GPL"); | |
247 | ||
248 | module_init(nforce2_s4985_init); | |
249 | module_exit(nforce2_s4985_exit); |