1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 Copyright (c) 2003 Mark M. Hoffman <mhoffman@lightlink.com>
4
5 */
6
7 /*
8 This module must be considered BETA unless and until
9 the chipset manufacturer releases a datasheet.
10 The register definitions are based on the SiS630.
11
12 This module relies on quirk_sis_96x_smbus (drivers/pci/quirks.c)
13 for just about every machine for which users have reported.
14 If this module isn't detecting your 96x south bridge, have a
15 look there.
16
17 We assume there can only be one SiS96x with one SMBus interface.
18 */
19
20 #include <linux/module.h>
21 #include <linux/pci.h>
22 #include <linux/kernel.h>
23 #include <linux/delay.h>
24 #include <linux/stddef.h>
25 #include <linux/ioport.h>
26 #include <linux/i2c.h>
27 #include <linux/acpi.h>
28 #include <linux/io.h>
29
30 /* base address register in PCI config space */
31 #define SIS96x_BAR 0x04
32
33 /* SiS96x SMBus registers */
34 #define SMB_STS 0x00
35 #define SMB_EN 0x01
36 #define SMB_CNT 0x02
37 #define SMB_HOST_CNT 0x03
38 #define SMB_ADDR 0x04
39 #define SMB_CMD 0x05
40 #define SMB_PCOUNT 0x06
41 #define SMB_COUNT 0x07
42 #define SMB_BYTE 0x08
43 #define SMB_DEV_ADDR 0x10
44 #define SMB_DB0 0x11
45 #define SMB_DB1 0x12
46 #define SMB_SAA 0x13
47
48 /* register count for request_region */
49 #define SMB_IOSIZE 0x20
50
51 /* Other settings */
52 #define MAX_TIMEOUT 500
53
54 /* SiS96x SMBus constants */
55 #define SIS96x_QUICK 0x00
56 #define SIS96x_BYTE 0x01
57 #define SIS96x_BYTE_DATA 0x02
58 #define SIS96x_WORD_DATA 0x03
59 #define SIS96x_PROC_CALL 0x04
60 #define SIS96x_BLOCK_DATA 0x05
61
62 static struct pci_driver sis96x_driver;
63 static struct i2c_adapter sis96x_adapter;
64 static u16 sis96x_smbus_base;
65
sis96x_read(u8 reg)66 static inline u8 sis96x_read(u8 reg)
67 {
68 return inb(sis96x_smbus_base + reg) ;
69 }
70
sis96x_write(u8 reg,u8 data)71 static inline void sis96x_write(u8 reg, u8 data)
72 {
73 outb(data, sis96x_smbus_base + reg) ;
74 }
75
76 /* Execute a SMBus transaction.
77 int size is from SIS96x_QUICK to SIS96x_BLOCK_DATA
78 */
sis96x_transaction(int size)79 static int sis96x_transaction(int size)
80 {
81 int temp;
82 int result = 0;
83 int timeout = 0;
84
85 dev_dbg(&sis96x_adapter.dev, "SMBus transaction %d\n", size);
86
87 /* Make sure the SMBus host is ready to start transmitting */
88 if (((temp = sis96x_read(SMB_CNT)) & 0x03) != 0x00) {
89
90 dev_dbg(&sis96x_adapter.dev, "SMBus busy (0x%02x). "
91 "Resetting...\n", temp);
92
93 /* kill the transaction */
94 sis96x_write(SMB_HOST_CNT, 0x20);
95
96 /* check it again */
97 if (((temp = sis96x_read(SMB_CNT)) & 0x03) != 0x00) {
98 dev_dbg(&sis96x_adapter.dev, "Failed (0x%02x)\n", temp);
99 return -EBUSY;
100 } else {
101 dev_dbg(&sis96x_adapter.dev, "Successful\n");
102 }
103 }
104
105 /* Turn off timeout interrupts, set fast host clock */
106 sis96x_write(SMB_CNT, 0x20);
107
108 /* clear all (sticky) status flags */
109 temp = sis96x_read(SMB_STS);
110 sis96x_write(SMB_STS, temp & 0x1e);
111
112 /* start the transaction by setting bit 4 and size bits */
113 sis96x_write(SMB_HOST_CNT, 0x10 | (size & 0x07));
114
115 /* We will always wait for a fraction of a second! */
116 do {
117 msleep(1);
118 temp = sis96x_read(SMB_STS);
119 } while (!(temp & 0x0e) && (timeout++ < MAX_TIMEOUT));
120
121 /* If the SMBus is still busy, we give up */
122 if (timeout > MAX_TIMEOUT) {
123 dev_dbg(&sis96x_adapter.dev, "SMBus Timeout! (0x%02x)\n", temp);
124 result = -ETIMEDOUT;
125 }
126
127 /* device error - probably missing ACK */
128 if (temp & 0x02) {
129 dev_dbg(&sis96x_adapter.dev, "Failed bus transaction!\n");
130 result = -ENXIO;
131 }
132
133 /* bus collision */
134 if (temp & 0x04) {
135 dev_dbg(&sis96x_adapter.dev, "Bus collision!\n");
136 result = -EIO;
137 }
138
139 /* Finish up by resetting the bus */
140 sis96x_write(SMB_STS, temp);
141 if ((temp = sis96x_read(SMB_STS))) {
142 dev_dbg(&sis96x_adapter.dev, "Failed reset at "
143 "end of transaction! (0x%02x)\n", temp);
144 }
145
146 return result;
147 }
148
149 /* Return negative errno on error. */
sis96x_access(struct i2c_adapter * adap,u16 addr,unsigned short flags,char read_write,u8 command,int size,union i2c_smbus_data * data)150 static s32 sis96x_access(struct i2c_adapter * adap, u16 addr,
151 unsigned short flags, char read_write,
152 u8 command, int size, union i2c_smbus_data * data)
153 {
154 int status;
155
156 switch (size) {
157 case I2C_SMBUS_QUICK:
158 sis96x_write(SMB_ADDR, ((addr & 0x7f) << 1) | (read_write & 0x01));
159 size = SIS96x_QUICK;
160 break;
161
162 case I2C_SMBUS_BYTE:
163 sis96x_write(SMB_ADDR, ((addr & 0x7f) << 1) | (read_write & 0x01));
164 if (read_write == I2C_SMBUS_WRITE)
165 sis96x_write(SMB_CMD, command);
166 size = SIS96x_BYTE;
167 break;
168
169 case I2C_SMBUS_BYTE_DATA:
170 sis96x_write(SMB_ADDR, ((addr & 0x7f) << 1) | (read_write & 0x01));
171 sis96x_write(SMB_CMD, command);
172 if (read_write == I2C_SMBUS_WRITE)
173 sis96x_write(SMB_BYTE, data->byte);
174 size = SIS96x_BYTE_DATA;
175 break;
176
177 case I2C_SMBUS_PROC_CALL:
178 case I2C_SMBUS_WORD_DATA:
179 sis96x_write(SMB_ADDR, ((addr & 0x7f) << 1) | (read_write & 0x01));
180 sis96x_write(SMB_CMD, command);
181 if (read_write == I2C_SMBUS_WRITE) {
182 sis96x_write(SMB_BYTE, data->word & 0xff);
183 sis96x_write(SMB_BYTE + 1, (data->word & 0xff00) >> 8);
184 }
185 size = (size == I2C_SMBUS_PROC_CALL ?
186 SIS96x_PROC_CALL : SIS96x_WORD_DATA);
187 break;
188
189 default:
190 dev_warn(&adap->dev, "Unsupported transaction %d\n", size);
191 return -EOPNOTSUPP;
192 }
193
194 status = sis96x_transaction(size);
195 if (status)
196 return status;
197
198 if ((size != SIS96x_PROC_CALL) &&
199 ((read_write == I2C_SMBUS_WRITE) || (size == SIS96x_QUICK)))
200 return 0;
201
202 switch (size) {
203 case SIS96x_BYTE:
204 case SIS96x_BYTE_DATA:
205 data->byte = sis96x_read(SMB_BYTE);
206 break;
207
208 case SIS96x_WORD_DATA:
209 case SIS96x_PROC_CALL:
210 data->word = sis96x_read(SMB_BYTE) +
211 (sis96x_read(SMB_BYTE + 1) << 8);
212 break;
213 }
214 return 0;
215 }
216
sis96x_func(struct i2c_adapter * adapter)217 static u32 sis96x_func(struct i2c_adapter *adapter)
218 {
219 return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
220 I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
221 I2C_FUNC_SMBUS_PROC_CALL;
222 }
223
224 static const struct i2c_algorithm smbus_algorithm = {
225 .smbus_xfer = sis96x_access,
226 .functionality = sis96x_func,
227 };
228
229 static struct i2c_adapter sis96x_adapter = {
230 .owner = THIS_MODULE,
231 .class = I2C_CLASS_HWMON | I2C_CLASS_SPD,
232 .algo = &smbus_algorithm,
233 };
234
235 static const struct pci_device_id sis96x_ids[] = {
236 { PCI_DEVICE(PCI_VENDOR_ID_SI, PCI_DEVICE_ID_SI_SMBUS) },
237 { 0, }
238 };
239
240 MODULE_DEVICE_TABLE (pci, sis96x_ids);
241
sis96x_probe(struct pci_dev * dev,const struct pci_device_id * id)242 static int sis96x_probe(struct pci_dev *dev,
243 const struct pci_device_id *id)
244 {
245 u16 ww = 0;
246 int retval;
247
248 if (sis96x_smbus_base) {
249 dev_err(&dev->dev, "Only one device supported.\n");
250 return -EBUSY;
251 }
252
253 pci_read_config_word(dev, PCI_CLASS_DEVICE, &ww);
254 if (PCI_CLASS_SERIAL_SMBUS != ww) {
255 dev_err(&dev->dev, "Unsupported device class 0x%04x!\n", ww);
256 return -ENODEV;
257 }
258
259 sis96x_smbus_base = pci_resource_start(dev, SIS96x_BAR);
260 if (!sis96x_smbus_base) {
261 dev_err(&dev->dev, "SiS96x SMBus base address "
262 "not initialized!\n");
263 return -EINVAL;
264 }
265 dev_info(&dev->dev, "SiS96x SMBus base address: 0x%04x\n",
266 sis96x_smbus_base);
267
268 retval = acpi_check_resource_conflict(&dev->resource[SIS96x_BAR]);
269 if (retval)
270 return -ENODEV;
271
272 /* Everything is happy, let's grab the memory and set things up. */
273 if (!request_region(sis96x_smbus_base, SMB_IOSIZE,
274 sis96x_driver.name)) {
275 dev_err(&dev->dev, "SMBus registers 0x%04x-0x%04x "
276 "already in use!\n", sis96x_smbus_base,
277 sis96x_smbus_base + SMB_IOSIZE - 1);
278
279 sis96x_smbus_base = 0;
280 return -EINVAL;
281 }
282
283 /* set up the sysfs linkage to our parent device */
284 sis96x_adapter.dev.parent = &dev->dev;
285
286 snprintf(sis96x_adapter.name, sizeof(sis96x_adapter.name),
287 "SiS96x SMBus adapter at 0x%04x", sis96x_smbus_base);
288
289 if ((retval = i2c_add_adapter(&sis96x_adapter))) {
290 dev_err(&dev->dev, "Couldn't register adapter!\n");
291 release_region(sis96x_smbus_base, SMB_IOSIZE);
292 sis96x_smbus_base = 0;
293 }
294
295 return retval;
296 }
297
sis96x_remove(struct pci_dev * dev)298 static void sis96x_remove(struct pci_dev *dev)
299 {
300 if (sis96x_smbus_base) {
301 i2c_del_adapter(&sis96x_adapter);
302 release_region(sis96x_smbus_base, SMB_IOSIZE);
303 sis96x_smbus_base = 0;
304 }
305 }
306
307 static struct pci_driver sis96x_driver = {
308 .name = "sis96x_smbus",
309 .id_table = sis96x_ids,
310 .probe = sis96x_probe,
311 .remove = sis96x_remove,
312 };
313
314 module_pci_driver(sis96x_driver);
315
316 MODULE_AUTHOR("Mark M. Hoffman <mhoffman@lightlink.com>");
317 MODULE_DESCRIPTION("SiS96x SMBus driver");
318 MODULE_LICENSE("GPL");
319