1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18#include <linux/module.h>
19#include <linux/platform_device.h>
20#include <linux/kernel.h>
21#include <linux/delay.h>
22#include <linux/stddef.h>
23#include <linux/ioport.h>
24#include <linux/i2c.h>
25#include <linux/io.h>
26
27
28#define SMBHSTCNT (0 + sch_smba)
29#define SMBHSTSTS (1 + sch_smba)
30#define SMBHSTCLK (2 + sch_smba)
31#define SMBHSTADD (4 + sch_smba)
32#define SMBHSTCMD (5 + sch_smba)
33#define SMBHSTDAT0 (6 + sch_smba)
34#define SMBHSTDAT1 (7 + sch_smba)
35#define SMBBLKDAT (0x20 + sch_smba)
36
37
38#define MAX_RETRIES 5000
39
40
41#define SCH_QUICK 0x00
42#define SCH_BYTE 0x01
43#define SCH_BYTE_DATA 0x02
44#define SCH_WORD_DATA 0x03
45#define SCH_BLOCK_DATA 0x05
46
47static unsigned short sch_smba;
48static struct i2c_adapter sch_adapter;
49static int backbone_speed = 33000;
50module_param(backbone_speed, int, S_IRUSR | S_IWUSR);
51MODULE_PARM_DESC(backbone_speed, "Backbone speed in kHz, (default = 33000)");
52
53
54
55
56
57
58static int sch_transaction(void)
59{
60 int temp;
61 int result = 0;
62 int retries = 0;
63
64 dev_dbg(&sch_adapter.dev, "Transaction (pre): CNT=%02x, CMD=%02x, "
65 "ADD=%02x, DAT0=%02x, DAT1=%02x\n", inb(SMBHSTCNT),
66 inb(SMBHSTCMD), inb(SMBHSTADD), inb(SMBHSTDAT0),
67 inb(SMBHSTDAT1));
68
69
70 temp = inb(SMBHSTSTS) & 0x0f;
71 if (temp) {
72
73 if (temp & 0x01) {
74 dev_dbg(&sch_adapter.dev, "Completion (%02x). "
75 "Clear...\n", temp);
76 }
77 if (temp & 0x06) {
78 dev_dbg(&sch_adapter.dev, "SMBus error (%02x). "
79 "Resetting...\n", temp);
80 }
81 outb(temp, SMBHSTSTS);
82 temp = inb(SMBHSTSTS) & 0x0f;
83 if (temp) {
84 dev_err(&sch_adapter.dev,
85 "SMBus is not ready: (%02x)\n", temp);
86 return -EAGAIN;
87 }
88 }
89
90
91 outb(inb(SMBHSTCNT) | 0x10, SMBHSTCNT);
92
93 do {
94 usleep_range(100, 200);
95 temp = inb(SMBHSTSTS) & 0x0f;
96 } while ((temp & 0x08) && (retries++ < MAX_RETRIES));
97
98
99 if (retries > MAX_RETRIES) {
100 dev_err(&sch_adapter.dev, "SMBus Timeout!\n");
101 result = -ETIMEDOUT;
102 }
103 if (temp & 0x04) {
104 result = -EIO;
105 dev_dbg(&sch_adapter.dev, "Bus collision! SMBus may be "
106 "locked until next hard reset. (sorry!)\n");
107
108 } else if (temp & 0x02) {
109 result = -EIO;
110 dev_err(&sch_adapter.dev, "Error: no response!\n");
111 } else if (temp & 0x01) {
112 dev_dbg(&sch_adapter.dev, "Post complete!\n");
113 outb(temp, SMBHSTSTS);
114 temp = inb(SMBHSTSTS) & 0x07;
115 if (temp & 0x06) {
116
117 dev_dbg(&sch_adapter.dev, "Failed reset at end of "
118 "transaction (%02x), Bus error!\n", temp);
119 }
120 } else {
121 result = -ENXIO;
122 dev_dbg(&sch_adapter.dev, "No such address.\n");
123 }
124 dev_dbg(&sch_adapter.dev, "Transaction (post): CNT=%02x, CMD=%02x, "
125 "ADD=%02x, DAT0=%02x, DAT1=%02x\n", inb(SMBHSTCNT),
126 inb(SMBHSTCMD), inb(SMBHSTADD), inb(SMBHSTDAT0),
127 inb(SMBHSTDAT1));
128 return result;
129}
130
131
132
133
134
135
136
137
138static s32 sch_access(struct i2c_adapter *adap, u16 addr,
139 unsigned short flags, char read_write,
140 u8 command, int size, union i2c_smbus_data *data)
141{
142 int i, len, temp, rc;
143
144
145 temp = inb(SMBHSTSTS) & 0x0f;
146 if (temp & 0x08) {
147 dev_dbg(&sch_adapter.dev, "SMBus busy (%02x)\n", temp);
148 return -EAGAIN;
149 }
150 temp = inw(SMBHSTCLK);
151 if (!temp) {
152
153
154
155
156
157
158 dev_notice(&sch_adapter.dev,
159 "Clock divider uninitialized. Setting defaults\n");
160 outw(backbone_speed / (4 * 100), SMBHSTCLK);
161 }
162
163 dev_dbg(&sch_adapter.dev, "access size: %d %s\n", size,
164 (read_write)?"READ":"WRITE");
165 switch (size) {
166 case I2C_SMBUS_QUICK:
167 outb((addr << 1) | read_write, SMBHSTADD);
168 size = SCH_QUICK;
169 break;
170 case I2C_SMBUS_BYTE:
171 outb((addr << 1) | read_write, SMBHSTADD);
172 if (read_write == I2C_SMBUS_WRITE)
173 outb(command, SMBHSTCMD);
174 size = SCH_BYTE;
175 break;
176 case I2C_SMBUS_BYTE_DATA:
177 outb((addr << 1) | read_write, SMBHSTADD);
178 outb(command, SMBHSTCMD);
179 if (read_write == I2C_SMBUS_WRITE)
180 outb(data->byte, SMBHSTDAT0);
181 size = SCH_BYTE_DATA;
182 break;
183 case I2C_SMBUS_WORD_DATA:
184 outb((addr << 1) | read_write, SMBHSTADD);
185 outb(command, SMBHSTCMD);
186 if (read_write == I2C_SMBUS_WRITE) {
187 outb(data->word & 0xff, SMBHSTDAT0);
188 outb((data->word & 0xff00) >> 8, SMBHSTDAT1);
189 }
190 size = SCH_WORD_DATA;
191 break;
192 case I2C_SMBUS_BLOCK_DATA:
193 outb((addr << 1) | read_write, SMBHSTADD);
194 outb(command, SMBHSTCMD);
195 if (read_write == I2C_SMBUS_WRITE) {
196 len = data->block[0];
197 if (len == 0 || len > I2C_SMBUS_BLOCK_MAX)
198 return -EINVAL;
199 outb(len, SMBHSTDAT0);
200 for (i = 1; i <= len; i++)
201 outb(data->block[i], SMBBLKDAT+i-1);
202 }
203 size = SCH_BLOCK_DATA;
204 break;
205 default:
206 dev_warn(&adap->dev, "Unsupported transaction %d\n", size);
207 return -EOPNOTSUPP;
208 }
209 dev_dbg(&sch_adapter.dev, "write size %d to 0x%04x\n", size, SMBHSTCNT);
210 outb((inb(SMBHSTCNT) & 0xb0) | (size & 0x7), SMBHSTCNT);
211
212 rc = sch_transaction();
213 if (rc)
214 return rc;
215
216 if ((read_write == I2C_SMBUS_WRITE) || (size == SCH_QUICK))
217 return 0;
218
219 switch (size) {
220 case SCH_BYTE:
221 case SCH_BYTE_DATA:
222 data->byte = inb(SMBHSTDAT0);
223 break;
224 case SCH_WORD_DATA:
225 data->word = inb(SMBHSTDAT0) + (inb(SMBHSTDAT1) << 8);
226 break;
227 case SCH_BLOCK_DATA:
228 data->block[0] = inb(SMBHSTDAT0);
229 if (data->block[0] == 0 || data->block[0] > I2C_SMBUS_BLOCK_MAX)
230 return -EPROTO;
231 for (i = 1; i <= data->block[0]; i++)
232 data->block[i] = inb(SMBBLKDAT+i-1);
233 break;
234 }
235 return 0;
236}
237
238static u32 sch_func(struct i2c_adapter *adapter)
239{
240 return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
241 I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
242 I2C_FUNC_SMBUS_BLOCK_DATA;
243}
244
245static const struct i2c_algorithm smbus_algorithm = {
246 .smbus_xfer = sch_access,
247 .functionality = sch_func,
248};
249
250static struct i2c_adapter sch_adapter = {
251 .owner = THIS_MODULE,
252 .class = I2C_CLASS_HWMON | I2C_CLASS_SPD,
253 .algo = &smbus_algorithm,
254};
255
256static int smbus_sch_probe(struct platform_device *dev)
257{
258 struct resource *res;
259 int retval;
260
261 res = platform_get_resource(dev, IORESOURCE_IO, 0);
262 if (!res)
263 return -EBUSY;
264
265 if (!devm_request_region(&dev->dev, res->start, resource_size(res),
266 dev->name)) {
267 dev_err(&dev->dev, "SMBus region 0x%x already in use!\n",
268 sch_smba);
269 return -EBUSY;
270 }
271
272 sch_smba = res->start;
273
274 dev_dbg(&dev->dev, "SMBA = 0x%X\n", sch_smba);
275
276
277 sch_adapter.dev.parent = &dev->dev;
278
279 snprintf(sch_adapter.name, sizeof(sch_adapter.name),
280 "SMBus SCH adapter at %04x", sch_smba);
281
282 retval = i2c_add_adapter(&sch_adapter);
283 if (retval)
284 sch_smba = 0;
285
286 return retval;
287}
288
289static int smbus_sch_remove(struct platform_device *pdev)
290{
291 if (sch_smba) {
292 i2c_del_adapter(&sch_adapter);
293 sch_smba = 0;
294 }
295
296 return 0;
297}
298
299static struct platform_driver smbus_sch_driver = {
300 .driver = {
301 .name = "isch_smbus",
302 },
303 .probe = smbus_sch_probe,
304 .remove = smbus_sch_remove,
305};
306
307module_platform_driver(smbus_sch_driver);
308
309MODULE_AUTHOR("Jacob Pan <jacob.jun.pan@intel.com>");
310MODULE_DESCRIPTION("Intel SCH SMBus driver");
311MODULE_LICENSE("GPL");
312MODULE_ALIAS("platform:isch_smbus");
313
