1 /*
2 i2c-isch.c - Linux kernel driver for Intel SCH chipset SMBus
3 - Based on i2c-piix4.c
4 Copyright (c) 1998 - 2002 Frodo Looijaard <frodol@dds.nl> and
5 Philip Edelbrock <phil@netroedge.com>
6 - Intel SCH support
7 Copyright (c) 2007 - 2008 Jacob Jun Pan <jacob.jun.pan@intel.com>
8
9 This program is free software; you can redistribute it and/or modify
10 it under the terms of the GNU General Public License version 2 as
11 published by the Free Software Foundation.
12
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
17 */
18
19 /*
20 Supports:
21 Intel SCH chipsets (AF82US15W, AF82US15L, AF82UL11L)
22 Note: we assume there can only be one device, with one SMBus interface.
23 */
24
25 #include <linux/module.h>
26 #include <linux/platform_device.h>
27 #include <linux/kernel.h>
28 #include <linux/delay.h>
29 #include <linux/stddef.h>
30 #include <linux/ioport.h>
31 #include <linux/i2c.h>
32 #include <linux/io.h>
33 #include <linux/acpi.h>
34
35 /* SCH SMBus address offsets */
36 #define SMBHSTCNT (0 + sch_smba)
37 #define SMBHSTSTS (1 + sch_smba)
38 #define SMBHSTCLK (2 + sch_smba)
39 #define SMBHSTADD (4 + sch_smba) /* TSA */
40 #define SMBHSTCMD (5 + sch_smba)
41 #define SMBHSTDAT0 (6 + sch_smba)
42 #define SMBHSTDAT1 (7 + sch_smba)
43 #define SMBBLKDAT (0x20 + sch_smba)
44
45 /* Other settings */
46 #define MAX_RETRIES 5000
47
48 /* I2C constants */
49 #define SCH_QUICK 0x00
50 #define SCH_BYTE 0x01
51 #define SCH_BYTE_DATA 0x02
52 #define SCH_WORD_DATA 0x03
53 #define SCH_BLOCK_DATA 0x05
54
55 static unsigned short sch_smba;
56 static struct i2c_adapter sch_adapter;
57 static int backbone_speed = 33000; /* backbone speed in kHz */
58 module_param(backbone_speed, int, S_IRUSR | S_IWUSR);
59 MODULE_PARM_DESC(backbone_speed, "Backbone speed in kHz, (default = 33000)");
60
61 /*
62 * Start the i2c transaction -- the i2c_access will prepare the transaction
63 * and this function will execute it.
64 * return 0 for success and others for failure.
65 */
sch_transaction(void)66 static int sch_transaction(void)
67 {
68 int temp;
69 int result = 0;
70 int retries = 0;
71
72 dev_dbg(&sch_adapter.dev, "Transaction (pre): CNT=%02x, CMD=%02x, "
73 "ADD=%02x, DAT0=%02x, DAT1=%02x\n", inb(SMBHSTCNT),
74 inb(SMBHSTCMD), inb(SMBHSTADD), inb(SMBHSTDAT0),
75 inb(SMBHSTDAT1));
76
77 /* Make sure the SMBus host is ready to start transmitting */
78 temp = inb(SMBHSTSTS) & 0x0f;
79 if (temp) {
80 /* Can not be busy since we checked it in sch_access */
81 if (temp & 0x01) {
82 dev_dbg(&sch_adapter.dev, "Completion (%02x). "
83 "Clear...\n", temp);
84 }
85 if (temp & 0x06) {
86 dev_dbg(&sch_adapter.dev, "SMBus error (%02x). "
87 "Resetting...\n", temp);
88 }
89 outb(temp, SMBHSTSTS);
90 temp = inb(SMBHSTSTS) & 0x0f;
91 if (temp) {
92 dev_err(&sch_adapter.dev,
93 "SMBus is not ready: (%02x)\n", temp);
94 return -EAGAIN;
95 }
96 }
97
98 /* start the transaction by setting bit 4 */
99 outb(inb(SMBHSTCNT) | 0x10, SMBHSTCNT);
100
101 do {
102 usleep_range(100, 200);
103 temp = inb(SMBHSTSTS) & 0x0f;
104 } while ((temp & 0x08) && (retries++ < MAX_RETRIES));
105
106 /* If the SMBus is still busy, we give up */
107 if (retries > MAX_RETRIES) {
108 dev_err(&sch_adapter.dev, "SMBus Timeout!\n");
109 result = -ETIMEDOUT;
110 }
111 if (temp & 0x04) {
112 result = -EIO;
113 dev_dbg(&sch_adapter.dev, "Bus collision! SMBus may be "
114 "locked until next hard reset. (sorry!)\n");
115 /* Clock stops and slave is stuck in mid-transmission */
116 } else if (temp & 0x02) {
117 result = -EIO;
118 dev_err(&sch_adapter.dev, "Error: no response!\n");
119 } else if (temp & 0x01) {
120 dev_dbg(&sch_adapter.dev, "Post complete!\n");
121 outb(temp, SMBHSTSTS);
122 temp = inb(SMBHSTSTS) & 0x07;
123 if (temp & 0x06) {
124 /* Completion clear failed */
125 dev_dbg(&sch_adapter.dev, "Failed reset at end of "
126 "transaction (%02x), Bus error!\n", temp);
127 }
128 } else {
129 result = -ENXIO;
130 dev_dbg(&sch_adapter.dev, "No such address.\n");
131 }
132 dev_dbg(&sch_adapter.dev, "Transaction (post): CNT=%02x, CMD=%02x, "
133 "ADD=%02x, DAT0=%02x, DAT1=%02x\n", inb(SMBHSTCNT),
134 inb(SMBHSTCMD), inb(SMBHSTADD), inb(SMBHSTDAT0),
135 inb(SMBHSTDAT1));
136 return result;
137 }
138
139 /*
140 * This is the main access entry for i2c-sch access
141 * adap is i2c_adapter pointer, addr is the i2c device bus address, read_write
142 * (0 for read and 1 for write), size is i2c transaction type and data is the
143 * union of transaction for data to be transferred or data read from bus.
144 * return 0 for success and others for failure.
145 */
sch_access(struct i2c_adapter * adap,u16 addr,unsigned short flags,char read_write,u8 command,int size,union i2c_smbus_data * data)146 static s32 sch_access(struct i2c_adapter *adap, u16 addr,
147 unsigned short flags, char read_write,
148 u8 command, int size, union i2c_smbus_data *data)
149 {
150 int i, len, temp, rc;
151
152 /* Make sure the SMBus host is not busy */
153 temp = inb(SMBHSTSTS) & 0x0f;
154 if (temp & 0x08) {
155 dev_dbg(&sch_adapter.dev, "SMBus busy (%02x)\n", temp);
156 return -EAGAIN;
157 }
158 temp = inw(SMBHSTCLK);
159 if (!temp) {
160 /*
161 * We can't determine if we have 33 or 25 MHz clock for
162 * SMBus, so expect 33 MHz and calculate a bus clock of
163 * 100 kHz. If we actually run at 25 MHz the bus will be
164 * run ~75 kHz instead which should do no harm.
165 */
166 dev_notice(&sch_adapter.dev,
167 "Clock divider uninitialized. Setting defaults\n");
168 outw(backbone_speed / (4 * 100), SMBHSTCLK);
169 }
170
171 dev_dbg(&sch_adapter.dev, "access size: %d %s\n", size,
172 (read_write)?"READ":"WRITE");
173 switch (size) {
174 case I2C_SMBUS_QUICK:
175 outb((addr << 1) | read_write, SMBHSTADD);
176 size = SCH_QUICK;
177 break;
178 case I2C_SMBUS_BYTE:
179 outb((addr << 1) | read_write, SMBHSTADD);
180 if (read_write == I2C_SMBUS_WRITE)
181 outb(command, SMBHSTCMD);
182 size = SCH_BYTE;
183 break;
184 case I2C_SMBUS_BYTE_DATA:
185 outb((addr << 1) | read_write, SMBHSTADD);
186 outb(command, SMBHSTCMD);
187 if (read_write == I2C_SMBUS_WRITE)
188 outb(data->byte, SMBHSTDAT0);
189 size = SCH_BYTE_DATA;
190 break;
191 case I2C_SMBUS_WORD_DATA:
192 outb((addr << 1) | read_write, SMBHSTADD);
193 outb(command, SMBHSTCMD);
194 if (read_write == I2C_SMBUS_WRITE) {
195 outb(data->word & 0xff, SMBHSTDAT0);
196 outb((data->word & 0xff00) >> 8, SMBHSTDAT1);
197 }
198 size = SCH_WORD_DATA;
199 break;
200 case I2C_SMBUS_BLOCK_DATA:
201 outb((addr << 1) | read_write, SMBHSTADD);
202 outb(command, SMBHSTCMD);
203 if (read_write == I2C_SMBUS_WRITE) {
204 len = data->block[0];
205 if (len == 0 || len > I2C_SMBUS_BLOCK_MAX)
206 return -EINVAL;
207 outb(len, SMBHSTDAT0);
208 for (i = 1; i <= len; i++)
209 outb(data->block[i], SMBBLKDAT+i-1);
210 }
211 size = SCH_BLOCK_DATA;
212 break;
213 default:
214 dev_warn(&adap->dev, "Unsupported transaction %d\n", size);
215 return -EOPNOTSUPP;
216 }
217 dev_dbg(&sch_adapter.dev, "write size %d to 0x%04x\n", size, SMBHSTCNT);
218 outb((inb(SMBHSTCNT) & 0xb0) | (size & 0x7), SMBHSTCNT);
219
220 rc = sch_transaction();
221 if (rc) /* Error in transaction */
222 return rc;
223
224 if ((read_write == I2C_SMBUS_WRITE) || (size == SCH_QUICK))
225 return 0;
226
227 switch (size) {
228 case SCH_BYTE:
229 case SCH_BYTE_DATA:
230 data->byte = inb(SMBHSTDAT0);
231 break;
232 case SCH_WORD_DATA:
233 data->word = inb(SMBHSTDAT0) + (inb(SMBHSTDAT1) << 8);
234 break;
235 case SCH_BLOCK_DATA:
236 data->block[0] = inb(SMBHSTDAT0);
237 if (data->block[0] == 0 || data->block[0] > I2C_SMBUS_BLOCK_MAX)
238 return -EPROTO;
239 for (i = 1; i <= data->block[0]; i++)
240 data->block[i] = inb(SMBBLKDAT+i-1);
241 break;
242 }
243 return 0;
244 }
245
sch_func(struct i2c_adapter * adapter)246 static u32 sch_func(struct i2c_adapter *adapter)
247 {
248 return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
249 I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
250 I2C_FUNC_SMBUS_BLOCK_DATA;
251 }
252
253 static const struct i2c_algorithm smbus_algorithm = {
254 .smbus_xfer = sch_access,
255 .functionality = sch_func,
256 };
257
258 static struct i2c_adapter sch_adapter = {
259 .owner = THIS_MODULE,
260 .class = I2C_CLASS_HWMON | I2C_CLASS_SPD,
261 .algo = &smbus_algorithm,
262 };
263
smbus_sch_probe(struct platform_device * dev)264 static int smbus_sch_probe(struct platform_device *dev)
265 {
266 struct resource *res;
267 int retval;
268
269 res = platform_get_resource(dev, IORESOURCE_IO, 0);
270 if (!res)
271 return -EBUSY;
272
273 if (!devm_request_region(&dev->dev, res->start, resource_size(res),
274 dev->name)) {
275 dev_err(&dev->dev, "SMBus region 0x%x already in use!\n",
276 sch_smba);
277 return -EBUSY;
278 }
279
280 sch_smba = res->start;
281
282 dev_dbg(&dev->dev, "SMBA = 0x%X\n", sch_smba);
283
284 /* set up the sysfs linkage to our parent device */
285 sch_adapter.dev.parent = &dev->dev;
286
287 snprintf(sch_adapter.name, sizeof(sch_adapter.name),
288 "SMBus SCH adapter at %04x", sch_smba);
289
290 retval = i2c_add_adapter(&sch_adapter);
291 if (retval)
292 sch_smba = 0;
293
294 return retval;
295 }
296
smbus_sch_remove(struct platform_device * pdev)297 static int smbus_sch_remove(struct platform_device *pdev)
298 {
299 if (sch_smba) {
300 i2c_del_adapter(&sch_adapter);
301 sch_smba = 0;
302 }
303
304 return 0;
305 }
306
307 static struct platform_driver smbus_sch_driver = {
308 .driver = {
309 .name = "isch_smbus",
310 },
311 .probe = smbus_sch_probe,
312 .remove = smbus_sch_remove,
313 };
314
315 module_platform_driver(smbus_sch_driver);
316
317 MODULE_AUTHOR("Jacob Pan <jacob.jun.pan@intel.com>");
318 MODULE_DESCRIPTION("Intel SCH SMBus driver");
319 MODULE_LICENSE("GPL");
320 MODULE_ALIAS("platform:isch_smbus");
321