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279e9024 JD |
1 | /* |
2 | * i2c-nforce2-s4985.c - i2c-nforce2 extras for the Tyan S4985 motherboard | |
3 | * | |
4 | * Copyright (C) 2008 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. We define one virtual | |
27 | * adapter per CPU, which corresponds to one multiplexed channel: | |
28 | * CPU0: virtual adapter 1, channel 1 | |
29 | * CPU1: virtual adapter 2, channel 2 | |
30 | * CPU2: virtual adapter 3, channel 3 | |
31 | * CPU3: virtual adapter 4, channel 4 | |
32 | */ | |
33 | ||
34 | #include <linux/module.h> | |
35 | #include <linux/kernel.h> | |
36 | #include <linux/slab.h> | |
37 | #include <linux/init.h> | |
38 | #include <linux/i2c.h> | |
39 | #include <linux/mutex.h> | |
40 | ||
41 | extern struct i2c_adapter *nforce2_smbus; | |
42 | ||
43 | static struct i2c_adapter *s4985_adapter; | |
44 | static struct i2c_algorithm *s4985_algo; | |
45 | ||
46 | /* Wrapper access functions for multiplexed SMBus */ | |
47 | static DEFINE_MUTEX(nforce2_lock); | |
48 | ||
49 | static s32 nforce2_access_virt0(struct i2c_adapter *adap, u16 addr, | |
50 | unsigned short flags, char read_write, | |
51 | u8 command, int size, | |
52 | union i2c_smbus_data *data) | |
53 | { | |
54 | int error; | |
55 | ||
56 | /* We exclude the multiplexed addresses */ | |
57 | if ((addr & 0xfc) == 0x50 || (addr & 0xfc) == 0x30 | |
58 | || addr == 0x18) | |
59 | return -ENXIO; | |
60 | ||
61 | mutex_lock(&nforce2_lock); | |
62 | error = nforce2_smbus->algo->smbus_xfer(adap, addr, flags, read_write, | |
63 | command, size, data); | |
64 | mutex_unlock(&nforce2_lock); | |
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 nforce2_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 & 0xfc) != 0x50 && (addr & 0xfc) != 0x30) | |
85 | return -ENXIO; | |
86 | ||
87 | mutex_lock(&nforce2_lock); | |
88 | if (last_channels != channels) { | |
89 | union i2c_smbus_data mplxdata; | |
90 | mplxdata.byte = channels; | |
91 | ||
92 | error = nforce2_smbus->algo->smbus_xfer(adap, 0x18, 0, | |
93 | I2C_SMBUS_WRITE, 0x01, | |
94 | I2C_SMBUS_BYTE_DATA, | |
95 | &mplxdata); | |
96 | if (error) | |
97 | goto UNLOCK; | |
98 | last_channels = channels; | |
99 | } | |
100 | error = nforce2_smbus->algo->smbus_xfer(adap, addr, flags, read_write, | |
101 | command, size, data); | |
102 | ||
103 | UNLOCK: | |
104 | mutex_unlock(&nforce2_lock); | |
105 | return error; | |
106 | } | |
107 | ||
108 | static s32 nforce2_access_virt1(struct i2c_adapter *adap, u16 addr, | |
109 | unsigned short flags, char read_write, | |
110 | u8 command, int size, | |
111 | union i2c_smbus_data *data) | |
112 | { | |
113 | /* CPU0: channel 1 enabled */ | |
114 | return nforce2_access_channel(adap, addr, flags, read_write, command, | |
115 | size, data, 0x02); | |
116 | } | |
117 | ||
118 | static s32 nforce2_access_virt2(struct i2c_adapter *adap, u16 addr, | |
119 | unsigned short flags, char read_write, | |
120 | u8 command, int size, | |
121 | union i2c_smbus_data *data) | |
122 | { | |
123 | /* CPU1: channel 2 enabled */ | |
124 | return nforce2_access_channel(adap, addr, flags, read_write, command, | |
125 | size, data, 0x04); | |
126 | } | |
127 | ||
128 | static s32 nforce2_access_virt3(struct i2c_adapter *adap, u16 addr, | |
129 | unsigned short flags, char read_write, | |
130 | u8 command, int size, | |
131 | union i2c_smbus_data *data) | |
132 | { | |
133 | /* CPU2: channel 3 enabled */ | |
134 | return nforce2_access_channel(adap, addr, flags, read_write, command, | |
135 | size, data, 0x08); | |
136 | } | |
137 | ||
138 | static s32 nforce2_access_virt4(struct i2c_adapter *adap, u16 addr, | |
139 | unsigned short flags, char read_write, | |
140 | u8 command, int size, | |
141 | union i2c_smbus_data *data) | |
142 | { | |
143 | /* CPU3: channel 4 enabled */ | |
144 | return nforce2_access_channel(adap, addr, flags, read_write, command, | |
145 | size, data, 0x10); | |
146 | } | |
147 | ||
148 | static int __init nforce2_s4985_init(void) | |
149 | { | |
150 | int i, error; | |
151 | union i2c_smbus_data ioconfig; | |
152 | ||
399d6b26 JD |
153 | if (!nforce2_smbus) |
154 | return -ENODEV; | |
155 | ||
bd4bc3db JD |
156 | /* Configure the PCA9556 multiplexer */ |
157 | ioconfig.byte = 0x00; /* All I/O to output mode */ | |
158 | error = i2c_smbus_xfer(nforce2_smbus, 0x18, 0, I2C_SMBUS_WRITE, 0x03, | |
159 | I2C_SMBUS_BYTE_DATA, &ioconfig); | |
160 | if (error) { | |
161 | dev_err(&nforce2_smbus->dev, "PCA9556 configuration failed\n"); | |
162 | error = -EIO; | |
163 | goto ERROR0; | |
164 | } | |
165 | ||
279e9024 | 166 | /* Unregister physical bus */ |
279e9024 JD |
167 | error = i2c_del_adapter(nforce2_smbus); |
168 | if (error) { | |
169 | dev_err(&nforce2_smbus->dev, "Physical bus removal failed\n"); | |
170 | goto ERROR0; | |
171 | } | |
172 | ||
173 | printk(KERN_INFO "Enabling SMBus multiplexing for Tyan S4985\n"); | |
174 | /* Define the 5 virtual adapters and algorithms structures */ | |
175 | s4985_adapter = kzalloc(5 * sizeof(struct i2c_adapter), GFP_KERNEL); | |
176 | if (!s4985_adapter) { | |
177 | error = -ENOMEM; | |
178 | goto ERROR1; | |
179 | } | |
180 | s4985_algo = kzalloc(5 * sizeof(struct i2c_algorithm), GFP_KERNEL); | |
181 | if (!s4985_algo) { | |
182 | error = -ENOMEM; | |
183 | goto ERROR2; | |
184 | } | |
185 | ||
186 | /* Fill in the new structures */ | |
187 | s4985_algo[0] = *(nforce2_smbus->algo); | |
188 | s4985_algo[0].smbus_xfer = nforce2_access_virt0; | |
189 | s4985_adapter[0] = *nforce2_smbus; | |
190 | s4985_adapter[0].algo = s4985_algo; | |
191 | s4985_adapter[0].dev.parent = nforce2_smbus->dev.parent; | |
192 | for (i = 1; i < 5; i++) { | |
193 | s4985_algo[i] = *(nforce2_smbus->algo); | |
194 | s4985_adapter[i] = *nforce2_smbus; | |
195 | snprintf(s4985_adapter[i].name, sizeof(s4985_adapter[i].name), | |
196 | "SMBus nForce2 adapter (CPU%d)", i - 1); | |
197 | s4985_adapter[i].algo = s4985_algo + i; | |
198 | s4985_adapter[i].dev.parent = nforce2_smbus->dev.parent; | |
199 | } | |
200 | s4985_algo[1].smbus_xfer = nforce2_access_virt1; | |
201 | s4985_algo[2].smbus_xfer = nforce2_access_virt2; | |
202 | s4985_algo[3].smbus_xfer = nforce2_access_virt3; | |
203 | s4985_algo[4].smbus_xfer = nforce2_access_virt4; | |
204 | ||
279e9024 JD |
205 | /* Register virtual adapters */ |
206 | for (i = 0; i < 5; i++) { | |
207 | error = i2c_add_adapter(s4985_adapter + i); | |
208 | if (error) { | |
bd4bc3db JD |
209 | printk(KERN_ERR "i2c-nforce2-s4985: " |
210 | "Virtual adapter %d registration " | |
211 | "failed, module not inserted\n", i); | |
279e9024 JD |
212 | for (i--; i >= 0; i--) |
213 | i2c_del_adapter(s4985_adapter + i); | |
214 | goto ERROR3; | |
215 | } | |
216 | } | |
217 | ||
218 | return 0; | |
219 | ||
220 | ERROR3: | |
221 | kfree(s4985_algo); | |
222 | s4985_algo = NULL; | |
223 | ERROR2: | |
224 | kfree(s4985_adapter); | |
225 | s4985_adapter = NULL; | |
226 | ERROR1: | |
227 | /* Restore physical bus */ | |
228 | i2c_add_adapter(nforce2_smbus); | |
229 | ERROR0: | |
230 | return error; | |
231 | } | |
232 | ||
233 | static void __exit nforce2_s4985_exit(void) | |
234 | { | |
235 | if (s4985_adapter) { | |
236 | int i; | |
237 | ||
238 | for (i = 0; i < 5; i++) | |
239 | i2c_del_adapter(s4985_adapter+i); | |
240 | kfree(s4985_adapter); | |
241 | s4985_adapter = NULL; | |
242 | } | |
243 | kfree(s4985_algo); | |
244 | s4985_algo = NULL; | |
245 | ||
246 | /* Restore physical bus */ | |
247 | if (i2c_add_adapter(nforce2_smbus)) | |
bd4bc3db JD |
248 | printk(KERN_ERR "i2c-nforce2-s4985: " |
249 | "Physical bus restoration failed\n"); | |
279e9024 JD |
250 | } |
251 | ||
252 | MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>"); | |
253 | MODULE_DESCRIPTION("S4985 SMBus multiplexing"); | |
254 | MODULE_LICENSE("GPL"); | |
255 | ||
256 | module_init(nforce2_s4985_init); | |
257 | module_exit(nforce2_s4985_exit); |