]>
git.proxmox.com Git - mirror_ubuntu-jammy-kernel.git/blob - drivers/i2c/busses/i2c-amd756-s4882.c
2 * i2c-amd756-s4882.c - i2c-amd756 extras for the Tyan S4882 motherboard
4 * Copyright (C) 2004, 2008 Jean Delvare <khali@linux-fr.org>
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.
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.
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.
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
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
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>
41 #include <linux/mutex.h>
43 extern struct i2c_adapter amd756_smbus
;
45 static struct i2c_adapter
*s4882_adapter
;
46 static struct i2c_algorithm
*s4882_algo
;
48 /* Wrapper access functions for multiplexed SMBus */
49 static DEFINE_MUTEX(amd756_lock
);
51 static s32
amd756_access_virt0(struct i2c_adapter
* adap
, u16 addr
,
52 unsigned short flags
, char read_write
,
54 union i2c_smbus_data
* data
)
58 /* We exclude the multiplexed addresses */
59 if (addr
== 0x4c || (addr
& 0xfc) == 0x50 || (addr
& 0xfc) == 0x30
63 mutex_lock(&amd756_lock
);
65 error
= amd756_smbus
.algo
->smbus_xfer(adap
, addr
, flags
, read_write
,
68 mutex_unlock(&amd756_lock
);
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
77 static u8 last_channels
;
79 static inline s32
amd756_access_channel(struct i2c_adapter
* adap
, u16 addr
,
80 unsigned short flags
, char read_write
,
82 union i2c_smbus_data
* data
,
87 /* We exclude the non-multiplexed addresses */
88 if (addr
!= 0x4c && (addr
& 0xfc) != 0x50 && (addr
& 0xfc) != 0x30)
91 mutex_lock(&amd756_lock
);
93 if (last_channels
!= channels
) {
94 union i2c_smbus_data mplxdata
;
95 mplxdata
.byte
= channels
;
97 error
= amd756_smbus
.algo
->smbus_xfer(adap
, 0x18, 0,
98 I2C_SMBUS_WRITE
, 0x01,
103 last_channels
= channels
;
105 error
= amd756_smbus
.algo
->smbus_xfer(adap
, addr
, flags
, read_write
,
106 command
, size
, data
);
109 mutex_unlock(&amd756_lock
);
113 static 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
)
118 /* CPU0: channels 1 and 0 enabled */
119 return amd756_access_channel(adap
, addr
, flags
, read_write
, command
,
123 static 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
)
128 /* CPU1: channels 2 and 5 enabled */
129 return amd756_access_channel(adap
, addr
, flags
, read_write
, command
,
133 static 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
)
138 /* CPU2: channels 3 and 6 enabled */
139 return amd756_access_channel(adap
, addr
, flags
, read_write
, command
,
143 static 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
)
148 /* CPU3: channels 4 and 7 enabled */
149 return amd756_access_channel(adap
, addr
, flags
, read_write
, command
,
153 static int __init
amd756_s4882_init(void)
156 union i2c_smbus_data ioconfig
;
158 if (!amd756_smbus
.dev
.parent
)
161 /* Configure the PCA9556 multiplexer */
162 ioconfig
.byte
= 0x00; /* All I/O to output mode */
163 error
= i2c_smbus_xfer(&amd756_smbus
, 0x18, 0, I2C_SMBUS_WRITE
, 0x03,
164 I2C_SMBUS_BYTE_DATA
, &ioconfig
);
166 dev_err(&amd756_smbus
.dev
, "PCA9556 configuration failed\n");
171 /* Unregister physical bus */
172 error
= i2c_del_adapter(&amd756_smbus
);
174 dev_err(&amd756_smbus
.dev
, "Physical bus removal failed\n");
178 printk(KERN_INFO
"Enabling SMBus multiplexing for Tyan S4882\n");
179 /* Define the 5 virtual adapters and algorithms structures */
180 if (!(s4882_adapter
= kzalloc(5 * sizeof(struct i2c_adapter
),
185 if (!(s4882_algo
= kzalloc(5 * sizeof(struct i2c_algorithm
),
191 /* Fill in the new structures */
192 s4882_algo
[0] = *(amd756_smbus
.algo
);
193 s4882_algo
[0].smbus_xfer
= amd756_access_virt0
;
194 s4882_adapter
[0] = amd756_smbus
;
195 s4882_adapter
[0].algo
= s4882_algo
;
196 s4882_adapter
[0].dev
.parent
= amd756_smbus
.dev
.parent
;
197 for (i
= 1; i
< 5; i
++) {
198 s4882_algo
[i
] = *(amd756_smbus
.algo
);
199 s4882_adapter
[i
] = amd756_smbus
;
200 snprintf(s4882_adapter
[i
].name
, sizeof(s4882_adapter
[i
].name
),
201 "SMBus 8111 adapter (CPU%d)", i
-1);
202 s4882_adapter
[i
].algo
= s4882_algo
+i
;
203 s4882_adapter
[i
].dev
.parent
= amd756_smbus
.dev
.parent
;
205 s4882_algo
[1].smbus_xfer
= amd756_access_virt1
;
206 s4882_algo
[2].smbus_xfer
= amd756_access_virt2
;
207 s4882_algo
[3].smbus_xfer
= amd756_access_virt3
;
208 s4882_algo
[4].smbus_xfer
= amd756_access_virt4
;
210 /* Register virtual adapters */
211 for (i
= 0; i
< 5; i
++) {
212 error
= i2c_add_adapter(s4882_adapter
+i
);
214 printk(KERN_ERR
"i2c-amd756-s4882: "
215 "Virtual adapter %d registration "
216 "failed, module not inserted\n", i
);
217 for (i
--; i
>= 0; i
--)
218 i2c_del_adapter(s4882_adapter
+i
);
229 kfree(s4882_adapter
);
230 s4882_adapter
= NULL
;
232 /* Restore physical bus */
233 i2c_add_adapter(&amd756_smbus
);
238 static void __exit
amd756_s4882_exit(void)
243 for (i
= 0; i
< 5; i
++)
244 i2c_del_adapter(s4882_adapter
+i
);
245 kfree(s4882_adapter
);
246 s4882_adapter
= NULL
;
251 /* Restore physical bus */
252 if (i2c_add_adapter(&amd756_smbus
))
253 printk(KERN_ERR
"i2c-amd756-s4882: "
254 "Physical bus restoration failed\n");
257 MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>");
258 MODULE_DESCRIPTION("S4882 SMBus multiplexing");
259 MODULE_LICENSE("GPL");
261 module_init(amd756_s4882_init
);
262 module_exit(amd756_s4882_exit
);