1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
|
/*
i2c-isch.c - Linux kernel driver for Intel SCH chipset SMBus
- Based on i2c-piix4.c
Copyright (c) 1998 - 2002 Frodo Looijaard <frodol@dds.nl> and
Philip Edelbrock <phil@netroedge.com>
- Intel SCH support
Copyright (c) 2007 - 2008 Jacob Jun Pan <jacob.jun.pan@intel.com>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License version 2 as
published by the Free Software Foundation.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
*/
/*
Supports:
Intel SCH chipsets (AF82US15W, AF82US15L, AF82UL11L)
Note: we assume there can only be one device, with one SMBus interface.
*/
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/stddef.h>
#include <linux/ioport.h>
#include <linux/i2c.h>
#include <linux/io.h>
/* SCH SMBus address offsets */
#define SMBHSTCNT (0 + sch_smba)
#define SMBHSTSTS (1 + sch_smba)
#define SMBHSTCLK (2 + sch_smba)
#define SMBHSTADD (4 + sch_smba) /* TSA */
#define SMBHSTCMD (5 + sch_smba)
#define SMBHSTDAT0 (6 + sch_smba)
#define SMBHSTDAT1 (7 + sch_smba)
#define SMBBLKDAT (0x20 + sch_smba)
/* Other settings */
#define MAX_RETRIES 5000
/* I2C constants */
#define SCH_QUICK 0x00
#define SCH_BYTE 0x01
#define SCH_BYTE_DATA 0x02
#define SCH_WORD_DATA 0x03
#define SCH_BLOCK_DATA 0x05
static unsigned short sch_smba;
static struct i2c_adapter sch_adapter;
static int backbone_speed = 33000; /* backbone speed in kHz */
module_param(backbone_speed, int, S_IRUSR | S_IWUSR);
MODULE_PARM_DESC(backbone_speed, "Backbone speed in kHz, (default = 33000)");
/*
* Start the i2c transaction -- the i2c_access will prepare the transaction
* and this function will execute it.
* return 0 for success and others for failure.
*/
static int sch_transaction(void)
{
int temp;
int result = 0;
int retries = 0;
dev_dbg(&sch_adapter.dev, "Transaction (pre): CNT=%02x, CMD=%02x, "
"ADD=%02x, DAT0=%02x, DAT1=%02x\n", inb(SMBHSTCNT),
inb(SMBHSTCMD), inb(SMBHSTADD), inb(SMBHSTDAT0),
inb(SMBHSTDAT1));
/* Make sure the SMBus host is ready to start transmitting */
temp = inb(SMBHSTSTS) & 0x0f;
if (temp) {
/* Can not be busy since we checked it in sch_access */
if (temp & 0x01) {
dev_dbg(&sch_adapter.dev, "Completion (%02x). "
"Clear...\n", temp);
}
if (temp & 0x06) {
dev_dbg(&sch_adapter.dev, "SMBus error (%02x). "
"Resetting...\n", temp);
}
outb(temp, SMBHSTSTS);
temp = inb(SMBHSTSTS) & 0x0f;
if (temp) {
dev_err(&sch_adapter.dev,
"SMBus is not ready: (%02x)\n", temp);
return -EAGAIN;
}
}
/* start the transaction by setting bit 4 */
outb(inb(SMBHSTCNT) | 0x10, SMBHSTCNT);
do {
usleep_range(100, 200);
temp = inb(SMBHSTSTS) & 0x0f;
} while ((temp & 0x08) && (retries++ < MAX_RETRIES));
/* If the SMBus is still busy, we give up */
if (retries > MAX_RETRIES) {
dev_err(&sch_adapter.dev, "SMBus Timeout!\n");
result = -ETIMEDOUT;
}
if (temp & 0x04) {
result = -EIO;
dev_dbg(&sch_adapter.dev, "Bus collision! SMBus may be "
"locked until next hard reset. (sorry!)\n");
/* Clock stops and slave is stuck in mid-transmission */
} else if (temp & 0x02) {
result = -EIO;
dev_err(&sch_adapter.dev, "Error: no response!\n");
} else if (temp & 0x01) {
dev_dbg(&sch_adapter.dev, "Post complete!\n");
outb(temp, SMBHSTSTS);
temp = inb(SMBHSTSTS) & 0x07;
if (temp & 0x06) {
/* Completion clear failed */
dev_dbg(&sch_adapter.dev, "Failed reset at end of "
"transaction (%02x), Bus error!\n", temp);
}
} else {
result = -ENXIO;
dev_dbg(&sch_adapter.dev, "No such address.\n");
}
dev_dbg(&sch_adapter.dev, "Transaction (post): CNT=%02x, CMD=%02x, "
"ADD=%02x, DAT0=%02x, DAT1=%02x\n", inb(SMBHSTCNT),
inb(SMBHSTCMD), inb(SMBHSTADD), inb(SMBHSTDAT0),
inb(SMBHSTDAT1));
return result;
}
/*
* This is the main access entry for i2c-sch access
* adap is i2c_adapter pointer, addr is the i2c device bus address, read_write
* (0 for read and 1 for write), size is i2c transaction type and data is the
* union of transaction for data to be transferred or data read from bus.
* return 0 for success and others for failure.
*/
static s32 sch_access(struct i2c_adapter *adap, u16 addr,
unsigned short flags, char read_write,
u8 command, int size, union i2c_smbus_data *data)
{
int i, len, temp, rc;
/* Make sure the SMBus host is not busy */
temp = inb(SMBHSTSTS) & 0x0f;
if (temp & 0x08) {
dev_dbg(&sch_adapter.dev, "SMBus busy (%02x)\n", temp);
return -EAGAIN;
}
temp = inw(SMBHSTCLK);
if (!temp) {
/*
* We can't determine if we have 33 or 25 MHz clock for
* SMBus, so expect 33 MHz and calculate a bus clock of
* 100 kHz. If we actually run at 25 MHz the bus will be
* run ~75 kHz instead which should do no harm.
*/
dev_notice(&sch_adapter.dev,
"Clock divider uninitialized. Setting defaults\n");
outw(backbone_speed / (4 * 100), SMBHSTCLK);
}
dev_dbg(&sch_adapter.dev, "access size: %d %s\n", size,
(read_write)?"READ":"WRITE");
switch (size) {
case I2C_SMBUS_QUICK:
outb((addr << 1) | read_write, SMBHSTADD);
size = SCH_QUICK;
break;
case I2C_SMBUS_BYTE:
outb((addr << 1) | read_write, SMBHSTADD);
if (read_write == I2C_SMBUS_WRITE)
outb(command, SMBHSTCMD);
size = SCH_BYTE;
break;
case I2C_SMBUS_BYTE_DATA:
outb((addr << 1) | read_write, SMBHSTADD);
outb(command, SMBHSTCMD);
if (read_write == I2C_SMBUS_WRITE)
outb(data->byte, SMBHSTDAT0);
size = SCH_BYTE_DATA;
break;
case I2C_SMBUS_WORD_DATA:
outb((addr << 1) | read_write, SMBHSTADD);
outb(command, SMBHSTCMD);
if (read_write == I2C_SMBUS_WRITE) {
outb(data->word & 0xff, SMBHSTDAT0);
outb((data->word & 0xff00) >> 8, SMBHSTDAT1);
}
size = SCH_WORD_DATA;
break;
case I2C_SMBUS_BLOCK_DATA:
outb((addr << 1) | read_write, SMBHSTADD);
outb(command, SMBHSTCMD);
if (read_write == I2C_SMBUS_WRITE) {
len = data->block[0];
if (len == 0 || len > I2C_SMBUS_BLOCK_MAX)
return -EINVAL;
outb(len, SMBHSTDAT0);
for (i = 1; i <= len; i++)
outb(data->block[i], SMBBLKDAT+i-1);
}
size = SCH_BLOCK_DATA;
break;
default:
dev_warn(&adap->dev, "Unsupported transaction %d\n", size);
return -EOPNOTSUPP;
}
dev_dbg(&sch_adapter.dev, "write size %d to 0x%04x\n", size, SMBHSTCNT);
outb((inb(SMBHSTCNT) & 0xb0) | (size & 0x7), SMBHSTCNT);
rc = sch_transaction();
if (rc) /* Error in transaction */
return rc;
if ((read_write == I2C_SMBUS_WRITE) || (size == SCH_QUICK))
return 0;
switch (size) {
case SCH_BYTE:
case SCH_BYTE_DATA:
data->byte = inb(SMBHSTDAT0);
break;
case SCH_WORD_DATA:
data->word = inb(SMBHSTDAT0) + (inb(SMBHSTDAT1) << 8);
break;
case SCH_BLOCK_DATA:
data->block[0] = inb(SMBHSTDAT0);
if (data->block[0] == 0 || data->block[0] > I2C_SMBUS_BLOCK_MAX)
return -EPROTO;
for (i = 1; i <= data->block[0]; i++)
data->block[i] = inb(SMBBLKDAT+i-1);
break;
}
return 0;
}
static u32 sch_func(struct i2c_adapter *adapter)
{
return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
I2C_FUNC_SMBUS_BLOCK_DATA;
}
static const struct i2c_algorithm smbus_algorithm = {
.smbus_xfer = sch_access,
.functionality = sch_func,
};
static struct i2c_adapter sch_adapter = {
.owner = THIS_MODULE,
.class = I2C_CLASS_HWMON | I2C_CLASS_SPD,
.algo = &smbus_algorithm,
};
static int smbus_sch_probe(struct platform_device *dev)
{
struct resource *res;
int retval;
res = platform_get_resource(dev, IORESOURCE_IO, 0);
if (!res)
return -EBUSY;
if (!devm_request_region(&dev->dev, res->start, resource_size(res),
dev->name)) {
dev_err(&dev->dev, "SMBus region 0x%x already in use!\n",
sch_smba);
return -EBUSY;
}
sch_smba = res->start;
dev_dbg(&dev->dev, "SMBA = 0x%X\n", sch_smba);
/* set up the sysfs linkage to our parent device */
sch_adapter.dev.parent = &dev->dev;
snprintf(sch_adapter.name, sizeof(sch_adapter.name),
"SMBus SCH adapter at %04x", sch_smba);
retval = i2c_add_adapter(&sch_adapter);
if (retval)
sch_smba = 0;
return retval;
}
static int smbus_sch_remove(struct platform_device *pdev)
{
if (sch_smba) {
i2c_del_adapter(&sch_adapter);
sch_smba = 0;
}
return 0;
}
static struct platform_driver smbus_sch_driver = {
.driver = {
.name = "isch_smbus",
},
.probe = smbus_sch_probe,
.remove = smbus_sch_remove,
};
module_platform_driver(smbus_sch_driver);
MODULE_AUTHOR("Jacob Pan <jacob.jun.pan@intel.com>");
MODULE_DESCRIPTION("Intel SCH SMBus driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:isch_smbus");
|
