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c942fddf | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
1da177e4 LT |
2 | /* |
3 | * i2c-amd756-s4882.c - i2c-amd756 extras for the Tyan S4882 motherboard | |
4 | * | |
7c81c60f | 5 | * Copyright (C) 2004, 2008 Jean Delvare <jdelvare@suse.de> |
1da177e4 LT |
6 | */ |
7 | ||
8 | /* | |
9 | * We select the channels by sending commands to the Philips | |
10 | * PCA9556 chip at I2C address 0x18. The main adapter is used for | |
11 | * the non-multiplexed part of the bus, and 4 virtual adapters | |
12 | * are defined for the multiplexed addresses: 0x50-0x53 (memory | |
13 | * module EEPROM) located on channels 1-4, and 0x4c (LM63) | |
14 | * located on multiplexed channels 0 and 5-7. We define one | |
15 | * virtual adapter per CPU, which corresponds to two multiplexed | |
16 | * channels: | |
17 | * CPU0: virtual adapter 1, channels 1 and 0 | |
18 | * CPU1: virtual adapter 2, channels 2 and 5 | |
19 | * CPU2: virtual adapter 3, channels 3 and 6 | |
20 | * CPU3: virtual adapter 4, channels 4 and 7 | |
21 | */ | |
22 | ||
23 | #include <linux/module.h> | |
24 | #include <linux/kernel.h> | |
25 | #include <linux/slab.h> | |
26 | #include <linux/init.h> | |
27 | #include <linux/i2c.h> | |
5c085d36 | 28 | #include <linux/mutex.h> |
1da177e4 LT |
29 | |
30 | extern struct i2c_adapter amd756_smbus; | |
31 | ||
32 | static struct i2c_adapter *s4882_adapter; | |
33 | static struct i2c_algorithm *s4882_algo; | |
34 | ||
35 | /* Wrapper access functions for multiplexed SMBus */ | |
d7d2fe38 | 36 | static DEFINE_MUTEX(amd756_lock); |
1da177e4 LT |
37 | |
38 | static s32 amd756_access_virt0(struct i2c_adapter * adap, u16 addr, | |
39 | unsigned short flags, char read_write, | |
40 | u8 command, int size, | |
41 | union i2c_smbus_data * data) | |
42 | { | |
43 | int error; | |
44 | ||
45 | /* We exclude the multiplexed addresses */ | |
46 | if (addr == 0x4c || (addr & 0xfc) == 0x50 || (addr & 0xfc) == 0x30 | |
47 | || addr == 0x18) | |
97140342 | 48 | return -ENXIO; |
1da177e4 | 49 | |
5c085d36 | 50 | mutex_lock(&amd756_lock); |
1da177e4 LT |
51 | |
52 | error = amd756_smbus.algo->smbus_xfer(adap, addr, flags, read_write, | |
53 | command, size, data); | |
54 | ||
5c085d36 | 55 | mutex_unlock(&amd756_lock); |
1da177e4 LT |
56 | |
57 | return error; | |
58 | } | |
59 | ||
60 | /* We remember the last used channels combination so as to only switch | |
61 | channels when it is really needed. This greatly reduces the SMBus | |
62 | overhead, but also assumes that nobody will be writing to the PCA9556 | |
63 | in our back. */ | |
64 | static u8 last_channels; | |
65 | ||
66 | static inline s32 amd756_access_channel(struct i2c_adapter * adap, u16 addr, | |
67 | unsigned short flags, char read_write, | |
68 | u8 command, int size, | |
69 | union i2c_smbus_data * data, | |
70 | u8 channels) | |
71 | { | |
72 | int error; | |
73 | ||
74 | /* We exclude the non-multiplexed addresses */ | |
75 | if (addr != 0x4c && (addr & 0xfc) != 0x50 && (addr & 0xfc) != 0x30) | |
97140342 | 76 | return -ENXIO; |
1da177e4 | 77 | |
5c085d36 | 78 | mutex_lock(&amd756_lock); |
1da177e4 LT |
79 | |
80 | if (last_channels != channels) { | |
81 | union i2c_smbus_data mplxdata; | |
82 | mplxdata.byte = channels; | |
83 | ||
84 | error = amd756_smbus.algo->smbus_xfer(adap, 0x18, 0, | |
85 | I2C_SMBUS_WRITE, 0x01, | |
86 | I2C_SMBUS_BYTE_DATA, | |
87 | &mplxdata); | |
88 | if (error) | |
89 | goto UNLOCK; | |
90 | last_channels = channels; | |
91 | } | |
92 | error = amd756_smbus.algo->smbus_xfer(adap, addr, flags, read_write, | |
93 | command, size, data); | |
94 | ||
95 | UNLOCK: | |
5c085d36 | 96 | mutex_unlock(&amd756_lock); |
1da177e4 LT |
97 | return error; |
98 | } | |
99 | ||
100 | static s32 amd756_access_virt1(struct i2c_adapter * adap, u16 addr, | |
101 | unsigned short flags, char read_write, | |
102 | u8 command, int size, | |
103 | union i2c_smbus_data * data) | |
104 | { | |
105 | /* CPU0: channels 1 and 0 enabled */ | |
106 | return amd756_access_channel(adap, addr, flags, read_write, command, | |
107 | size, data, 0x03); | |
108 | } | |
109 | ||
110 | static s32 amd756_access_virt2(struct i2c_adapter * adap, u16 addr, | |
111 | unsigned short flags, char read_write, | |
112 | u8 command, int size, | |
113 | union i2c_smbus_data * data) | |
114 | { | |
115 | /* CPU1: channels 2 and 5 enabled */ | |
116 | return amd756_access_channel(adap, addr, flags, read_write, command, | |
117 | size, data, 0x24); | |
118 | } | |
119 | ||
120 | static s32 amd756_access_virt3(struct i2c_adapter * adap, u16 addr, | |
121 | unsigned short flags, char read_write, | |
122 | u8 command, int size, | |
123 | union i2c_smbus_data * data) | |
124 | { | |
125 | /* CPU2: channels 3 and 6 enabled */ | |
126 | return amd756_access_channel(adap, addr, flags, read_write, command, | |
127 | size, data, 0x48); | |
128 | } | |
129 | ||
130 | static s32 amd756_access_virt4(struct i2c_adapter * adap, u16 addr, | |
131 | unsigned short flags, char read_write, | |
132 | u8 command, int size, | |
133 | union i2c_smbus_data * data) | |
134 | { | |
135 | /* CPU3: channels 4 and 7 enabled */ | |
136 | return amd756_access_channel(adap, addr, flags, read_write, command, | |
137 | size, data, 0x90); | |
138 | } | |
139 | ||
140 | static int __init amd756_s4882_init(void) | |
141 | { | |
142 | int i, error; | |
143 | union i2c_smbus_data ioconfig; | |
144 | ||
399d6b26 JD |
145 | if (!amd756_smbus.dev.parent) |
146 | return -ENODEV; | |
147 | ||
bd4bc3db JD |
148 | /* Configure the PCA9556 multiplexer */ |
149 | ioconfig.byte = 0x00; /* All I/O to output mode */ | |
150 | error = i2c_smbus_xfer(&amd756_smbus, 0x18, 0, I2C_SMBUS_WRITE, 0x03, | |
151 | I2C_SMBUS_BYTE_DATA, &ioconfig); | |
152 | if (error) { | |
153 | dev_err(&amd756_smbus.dev, "PCA9556 configuration failed\n"); | |
154 | error = -EIO; | |
155 | goto ERROR0; | |
156 | } | |
157 | ||
1da177e4 | 158 | /* Unregister physical bus */ |
bf51a8c5 | 159 | i2c_del_adapter(&amd756_smbus); |
1da177e4 LT |
160 | |
161 | printk(KERN_INFO "Enabling SMBus multiplexing for Tyan S4882\n"); | |
1da177e4 | 162 | /* Define the 5 virtual adapters and algorithms structures */ |
6396bb22 | 163 | if (!(s4882_adapter = kcalloc(5, sizeof(struct i2c_adapter), |
1da177e4 LT |
164 | GFP_KERNEL))) { |
165 | error = -ENOMEM; | |
166 | goto ERROR1; | |
167 | } | |
6396bb22 | 168 | if (!(s4882_algo = kcalloc(5, sizeof(struct i2c_algorithm), |
1da177e4 LT |
169 | GFP_KERNEL))) { |
170 | error = -ENOMEM; | |
171 | goto ERROR2; | |
172 | } | |
173 | ||
174 | /* Fill in the new structures */ | |
175 | s4882_algo[0] = *(amd756_smbus.algo); | |
176 | s4882_algo[0].smbus_xfer = amd756_access_virt0; | |
177 | s4882_adapter[0] = amd756_smbus; | |
178 | s4882_adapter[0].algo = s4882_algo; | |
12a917f6 | 179 | s4882_adapter[0].dev.parent = amd756_smbus.dev.parent; |
1da177e4 LT |
180 | for (i = 1; i < 5; i++) { |
181 | s4882_algo[i] = *(amd756_smbus.algo); | |
182 | s4882_adapter[i] = amd756_smbus; | |
66c7acf6 JD |
183 | snprintf(s4882_adapter[i].name, sizeof(s4882_adapter[i].name), |
184 | "SMBus 8111 adapter (CPU%d)", i-1); | |
1da177e4 | 185 | s4882_adapter[i].algo = s4882_algo+i; |
12a917f6 | 186 | s4882_adapter[i].dev.parent = amd756_smbus.dev.parent; |
1da177e4 LT |
187 | } |
188 | s4882_algo[1].smbus_xfer = amd756_access_virt1; | |
189 | s4882_algo[2].smbus_xfer = amd756_access_virt2; | |
190 | s4882_algo[3].smbus_xfer = amd756_access_virt3; | |
191 | s4882_algo[4].smbus_xfer = amd756_access_virt4; | |
192 | ||
1da177e4 LT |
193 | /* Register virtual adapters */ |
194 | for (i = 0; i < 5; i++) { | |
195 | error = i2c_add_adapter(s4882_adapter+i); | |
196 | if (error) { | |
bd4bc3db | 197 | printk(KERN_ERR "i2c-amd756-s4882: " |
1da177e4 LT |
198 | "Virtual adapter %d registration " |
199 | "failed, module not inserted\n", i); | |
200 | for (i--; i >= 0; i--) | |
201 | i2c_del_adapter(s4882_adapter+i); | |
202 | goto ERROR3; | |
203 | } | |
204 | } | |
205 | ||
206 | return 0; | |
207 | ||
208 | ERROR3: | |
209 | kfree(s4882_algo); | |
210 | s4882_algo = NULL; | |
211 | ERROR2: | |
212 | kfree(s4882_adapter); | |
213 | s4882_adapter = NULL; | |
214 | ERROR1: | |
ee56d977 JD |
215 | /* Restore physical bus */ |
216 | i2c_add_adapter(&amd756_smbus); | |
1da177e4 LT |
217 | ERROR0: |
218 | return error; | |
219 | } | |
220 | ||
221 | static void __exit amd756_s4882_exit(void) | |
222 | { | |
223 | if (s4882_adapter) { | |
224 | int i; | |
225 | ||
226 | for (i = 0; i < 5; i++) | |
227 | i2c_del_adapter(s4882_adapter+i); | |
228 | kfree(s4882_adapter); | |
229 | s4882_adapter = NULL; | |
230 | } | |
6044ec88 JJ |
231 | kfree(s4882_algo); |
232 | s4882_algo = NULL; | |
1da177e4 LT |
233 | |
234 | /* Restore physical bus */ | |
235 | if (i2c_add_adapter(&amd756_smbus)) | |
bd4bc3db JD |
236 | printk(KERN_ERR "i2c-amd756-s4882: " |
237 | "Physical bus restoration failed\n"); | |
1da177e4 LT |
238 | } |
239 | ||
7c81c60f | 240 | MODULE_AUTHOR("Jean Delvare <jdelvare@suse.de>"); |
1da177e4 LT |
241 | MODULE_DESCRIPTION("S4882 SMBus multiplexing"); |
242 | MODULE_LICENSE("GPL"); | |
243 | ||
244 | module_init(amd756_s4882_init); | |
245 | module_exit(amd756_s4882_exit); |