1 | // SPDX-License-Identifier: GPL-2.0-or-later |
2 | /* |
3 | * i2c-amd756-s4882.c - i2c-amd756 extras for the Tyan S4882 motherboard |
4 | * |
5 | * Copyright (C) 2004, 2008 Jean Delvare <jdelvare@suse.de> |
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> |
28 | #include <linux/mutex.h> |
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 */ |
36 | static DEFINE_MUTEX(amd756_lock); |
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) |
48 | return -ENXIO; |
49 | |
50 | mutex_lock(&amd756_lock); |
51 | |
52 | error = amd756_smbus.algo->smbus_xfer(adap, addr, flags, read_write, |
53 | command, size, data); |
54 | |
55 | mutex_unlock(lock: &amd756_lock); |
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) |
76 | return -ENXIO; |
77 | |
78 | mutex_lock(&amd756_lock); |
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: |
96 | mutex_unlock(lock: &amd756_lock); |
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, channels: 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, channels: 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, channels: 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, channels: 0x90); |
138 | } |
139 | |
140 | static int __init amd756_s4882_init(void) |
141 | { |
142 | int i, error; |
143 | union i2c_smbus_data ioconfig; |
144 | |
145 | if (!amd756_smbus.dev.parent) |
146 | return -ENODEV; |
147 | |
148 | /* Configure the PCA9556 multiplexer */ |
149 | ioconfig.byte = 0x00; /* All I/O to output mode */ |
150 | error = i2c_smbus_xfer(adapter: &amd756_smbus, addr: 0x18, flags: 0, I2C_SMBUS_WRITE, command: 0x03, |
151 | I2C_SMBUS_BYTE_DATA, data: &ioconfig); |
152 | if (error) { |
153 | dev_err(&amd756_smbus.dev, "PCA9556 configuration failed\n" ); |
154 | error = -EIO; |
155 | goto ERROR0; |
156 | } |
157 | |
158 | /* Unregister physical bus */ |
159 | i2c_del_adapter(adap: &amd756_smbus); |
160 | |
161 | printk(KERN_INFO "Enabling SMBus multiplexing for Tyan S4882\n" ); |
162 | /* Define the 5 virtual adapters and algorithms structures */ |
163 | if (!(s4882_adapter = kcalloc(n: 5, size: sizeof(struct i2c_adapter), |
164 | GFP_KERNEL))) { |
165 | error = -ENOMEM; |
166 | goto ERROR1; |
167 | } |
168 | if (!(s4882_algo = kcalloc(n: 5, size: sizeof(struct i2c_algorithm), |
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; |
179 | s4882_adapter[0].dev.parent = amd756_smbus.dev.parent; |
180 | for (i = 1; i < 5; i++) { |
181 | s4882_algo[i] = *(amd756_smbus.algo); |
182 | s4882_adapter[i] = amd756_smbus; |
183 | snprintf(buf: s4882_adapter[i].name, size: sizeof(s4882_adapter[i].name), |
184 | fmt: "SMBus 8111 adapter (CPU%d)" , i-1); |
185 | s4882_adapter[i].algo = s4882_algo+i; |
186 | s4882_adapter[i].dev.parent = amd756_smbus.dev.parent; |
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 | |
193 | /* Register virtual adapters */ |
194 | for (i = 0; i < 5; i++) { |
195 | error = i2c_add_adapter(adap: s4882_adapter+i); |
196 | if (error) { |
197 | printk(KERN_ERR "i2c-amd756-s4882: " |
198 | "Virtual adapter %d registration " |
199 | "failed, module not inserted\n" , i); |
200 | for (i--; i >= 0; i--) |
201 | i2c_del_adapter(adap: s4882_adapter+i); |
202 | goto ERROR3; |
203 | } |
204 | } |
205 | |
206 | return 0; |
207 | |
208 | ERROR3: |
209 | kfree(objp: s4882_algo); |
210 | s4882_algo = NULL; |
211 | ERROR2: |
212 | kfree(objp: s4882_adapter); |
213 | s4882_adapter = NULL; |
214 | ERROR1: |
215 | /* Restore physical bus */ |
216 | i2c_add_adapter(adap: &amd756_smbus); |
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(adap: s4882_adapter+i); |
228 | kfree(objp: s4882_adapter); |
229 | s4882_adapter = NULL; |
230 | } |
231 | kfree(objp: s4882_algo); |
232 | s4882_algo = NULL; |
233 | |
234 | /* Restore physical bus */ |
235 | if (i2c_add_adapter(adap: &amd756_smbus)) |
236 | printk(KERN_ERR "i2c-amd756-s4882: " |
237 | "Physical bus restoration failed\n" ); |
238 | } |
239 | |
240 | MODULE_AUTHOR("Jean Delvare <jdelvare@suse.de>" ); |
241 | MODULE_DESCRIPTION("S4882 SMBus multiplexing" ); |
242 | MODULE_LICENSE("GPL" ); |
243 | |
244 | module_init(amd756_s4882_init); |
245 | module_exit(amd756_s4882_exit); |
246 | |