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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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>
Ingo Molnar5c085d32006-01-18 23:16:04 +010041#include <linux/mutex.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070042
43extern struct i2c_adapter amd756_smbus;
44
45static struct i2c_adapter *s4882_adapter;
46static struct i2c_algorithm *s4882_algo;
47
48/* Wrapper access functions for multiplexed SMBus */
Jean Delvared7d2fe32006-02-27 23:09:22 +010049static DEFINE_MUTEX(amd756_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -070050
51static 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)
61 return -1;
62
Ingo Molnar5c085d32006-01-18 23:16:04 +010063 mutex_lock(&amd756_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -070064
65 error = amd756_smbus.algo->smbus_xfer(adap, addr, flags, read_write,
66 command, size, data);
67
Ingo Molnar5c085d32006-01-18 23:16:04 +010068 mutex_unlock(&amd756_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -070069
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. */
77static u8 last_channels;
78
79static 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)
89 return -1;
90
Ingo Molnar5c085d32006-01-18 23:16:04 +010091 mutex_lock(&amd756_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -070092
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
108UNLOCK:
Ingo Molnar5c085d32006-01-18 23:16:04 +0100109 mutex_unlock(&amd756_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700110 return error;
111}
112
113static 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
123static 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
133static 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
143static 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
153static int __init amd756_s4882_init(void)
154{
155 int i, error;
156 union i2c_smbus_data ioconfig;
157
158 /* Unregister physical bus */
159 error = i2c_del_adapter(&amd756_smbus);
160 if (error) {
161 if (error == -EINVAL)
162 error = -ENODEV;
163 else
164 dev_err(&amd756_smbus.dev, "Physical bus removal "
165 "failed\n");
166 goto ERROR0;
167 }
168
169 printk(KERN_INFO "Enabling SMBus multiplexing for Tyan S4882\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700170 /* Define the 5 virtual adapters and algorithms structures */
Jean Delvaredeb875c72005-10-17 23:14:31 +0200171 if (!(s4882_adapter = kzalloc(5 * sizeof(struct i2c_adapter),
Linus Torvalds1da177e2005-04-16 15:20:36 -0700172 GFP_KERNEL))) {
173 error = -ENOMEM;
174 goto ERROR1;
175 }
Jean Delvaredeb875c72005-10-17 23:14:31 +0200176 if (!(s4882_algo = kzalloc(5 * sizeof(struct i2c_algorithm),
Linus Torvalds1da177e2005-04-16 15:20:36 -0700177 GFP_KERNEL))) {
178 error = -ENOMEM;
179 goto ERROR2;
180 }
181
182 /* Fill in the new structures */
183 s4882_algo[0] = *(amd756_smbus.algo);
184 s4882_algo[0].smbus_xfer = amd756_access_virt0;
185 s4882_adapter[0] = amd756_smbus;
186 s4882_adapter[0].algo = s4882_algo;
Jean Delvare12a917f2007-02-13 22:09:03 +0100187 s4882_adapter[0].dev.parent = amd756_smbus.dev.parent;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700188 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;
Jean Delvare12a917f2007-02-13 22:09:03 +0100194 s4882_adapter[i].dev.parent = amd756_smbus.dev.parent;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700195 }
196 s4882_algo[1].smbus_xfer = amd756_access_virt1;
197 s4882_algo[2].smbus_xfer = amd756_access_virt2;
198 s4882_algo[3].smbus_xfer = amd756_access_virt3;
199 s4882_algo[4].smbus_xfer = amd756_access_virt4;
200
201 /* Configure the PCA9556 multiplexer */
202 ioconfig.byte = 0x00; /* All I/O to output mode */
203 error = amd756_smbus.algo->smbus_xfer(&amd756_smbus, 0x18, 0,
204 I2C_SMBUS_WRITE, 0x03,
205 I2C_SMBUS_BYTE_DATA, &ioconfig);
206 if (error) {
207 dev_err(&amd756_smbus.dev, "PCA9556 configuration failed\n");
208 error = -EIO;
209 goto ERROR3;
210 }
211
212 /* Register virtual adapters */
213 for (i = 0; i < 5; i++) {
214 error = i2c_add_adapter(s4882_adapter+i);
215 if (error) {
216 dev_err(&amd756_smbus.dev,
217 "Virtual adapter %d registration "
218 "failed, module not inserted\n", i);
219 for (i--; i >= 0; i--)
220 i2c_del_adapter(s4882_adapter+i);
221 goto ERROR3;
222 }
223 }
224
225 return 0;
226
227ERROR3:
228 kfree(s4882_algo);
229 s4882_algo = NULL;
230ERROR2:
231 kfree(s4882_adapter);
232 s4882_adapter = NULL;
233ERROR1:
234 i2c_del_adapter(&amd756_smbus);
235ERROR0:
236 return error;
237}
238
239static 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 }
Jesper Juhl6044ec82005-11-07 01:01:32 -0800249 kfree(s4882_algo);
250 s4882_algo = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700251
252 /* Restore physical bus */
253 if (i2c_add_adapter(&amd756_smbus))
254 dev_err(&amd756_smbus.dev, "Physical bus restoration "
255 "failed\n");
256}
257
258MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>");
259MODULE_DESCRIPTION("S4882 SMBus multiplexing");
260MODULE_LICENSE("GPL");
261
262module_init(amd756_s4882_init);
263module_exit(amd756_s4882_exit);