hwmon: (w83l785ts) Simplify code and improve readability
[linux-2.6-block.git] / drivers / hwmon / w83l785ts.c
CommitLineData
1da177e4
LT
1/*
2 * w83l785ts.c - Part of lm_sensors, Linux kernel modules for hardware
3 * monitoring
a1fa4cdc 4 * Copyright (C) 2003-2009 Jean Delvare <khali@linux-fr.org>
1da177e4
LT
5 *
6 * Inspired from the lm83 driver. The W83L785TS-S is a sensor chip made
7 * by Winbond. It reports a single external temperature with a 1 deg
8 * resolution and a 3 deg accuracy. Datasheet can be obtained from
9 * Winbond's website at:
10 * http://www.winbond-usa.com/products/winbond_products/pdfs/PCIC/W83L785TS-S.pdf
11 *
12 * Ported to Linux 2.6 by Wolfgang Ziegler <nuppla@gmx.at> and Jean Delvare
13 * <khali@linux-fr.org>.
14 *
15 * Thanks to James Bolt <james@evilpenguin.com> for benchmarking the read
16 * error handling mechanism.
17 *
18 * This program is free software; you can redistribute it and/or modify
19 * it under the terms of the GNU General Public License as published by
20 * the Free Software Foundation; either version 2 of the License, or
21 * (at your option) any later version.
22 *
23 * This program is distributed in the hope that it will be useful,
24 * but WITHOUT ANY WARRANTY; without even the implied warranty of
25 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
26 * GNU General Public License for more details.
27 *
28 * You should have received a copy of the GNU General Public License
29 * along with this program; if not, write to the Free Software
30 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
31 */
32
1da177e4
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33#include <linux/module.h>
34#include <linux/delay.h>
35#include <linux/init.h>
36#include <linux/slab.h>
37#include <linux/jiffies.h>
38#include <linux/i2c.h>
943b0830 39#include <linux/hwmon.h>
709439a2 40#include <linux/hwmon-sysfs.h>
943b0830 41#include <linux/err.h>
9a61bf63 42#include <linux/mutex.h>
1da177e4
LT
43
44/* How many retries on register read error */
45#define MAX_RETRIES 5
46
47/*
48 * Address to scan
49 * Address is fully defined internally and cannot be changed.
50 */
51
25e9c86d 52static const unsigned short normal_i2c[] = { 0x2e, I2C_CLIENT_END };
1da177e4 53
1da177e4
LT
54/*
55 * The W83L785TS-S registers
56 * Manufacturer ID is 0x5CA3 for Winbond.
57 */
58
59#define W83L785TS_REG_MAN_ID1 0x4D
60#define W83L785TS_REG_MAN_ID2 0x4C
61#define W83L785TS_REG_CHIP_ID 0x4E
62#define W83L785TS_REG_CONFIG 0x40
63#define W83L785TS_REG_TYPE 0x52
64#define W83L785TS_REG_TEMP 0x27
65#define W83L785TS_REG_TEMP_OVER 0x53 /* not sure about this one */
66
67/*
68 * Conversions
69 * The W83L785TS-S uses signed 8-bit values.
70 */
71
cb929eae 72#define TEMP_FROM_REG(val) ((val) * 1000)
1da177e4
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73
74/*
75 * Functions declaration
76 */
77
dc18a418
JD
78static int w83l785ts_probe(struct i2c_client *client,
79 const struct i2c_device_id *id);
310ec792 80static int w83l785ts_detect(struct i2c_client *client,
dc18a418
JD
81 struct i2c_board_info *info);
82static int w83l785ts_remove(struct i2c_client *client);
1da177e4
LT
83static u8 w83l785ts_read_value(struct i2c_client *client, u8 reg, u8 defval);
84static struct w83l785ts_data *w83l785ts_update_device(struct device *dev);
85
86/*
87 * Driver data (common to all clients)
88 */
59965425 89
dc18a418 90static const struct i2c_device_id w83l785ts_id[] = {
1f86df49 91 { "w83l785ts", 0 },
dc18a418
JD
92 { }
93};
94MODULE_DEVICE_TABLE(i2c, w83l785ts_id);
95
1da177e4 96static struct i2c_driver w83l785ts_driver = {
dc18a418 97 .class = I2C_CLASS_HWMON,
cdaf7934 98 .driver = {
cdaf7934
LR
99 .name = "w83l785ts",
100 },
dc18a418
JD
101 .probe = w83l785ts_probe,
102 .remove = w83l785ts_remove,
103 .id_table = w83l785ts_id,
104 .detect = w83l785ts_detect,
c3813d6a 105 .address_list = normal_i2c,
1da177e4
LT
106};
107
108/*
109 * Client data (each client gets its own)
110 */
111
112struct w83l785ts_data {
1beeffe4 113 struct device *hwmon_dev;
9a61bf63 114 struct mutex update_lock;
1da177e4
LT
115 char valid; /* zero until following fields are valid */
116 unsigned long last_updated; /* in jiffies */
117
118 /* registers values */
130067d7 119 s8 temp[2]; /* 0: input, 1: critical limit */
1da177e4
LT
120};
121
122/*
123 * Sysfs stuff
124 */
125
709439a2
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126static ssize_t show_temp(struct device *dev, struct device_attribute *devattr,
127 char *buf)
1da177e4 128{
709439a2 129 struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
1da177e4 130 struct w83l785ts_data *data = w83l785ts_update_device(dev);
709439a2 131 return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp[attr->index]));
1da177e4
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132}
133
709439a2
JD
134static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0);
135static SENSOR_DEVICE_ATTR(temp1_max, S_IRUGO, show_temp, NULL, 1);
1da177e4
LT
136
137/*
138 * Real code
139 */
140
dc18a418 141/* Return 0 if detection is successful, -ENODEV otherwise */
310ec792 142static int w83l785ts_detect(struct i2c_client *client,
dc18a418 143 struct i2c_board_info *info)
1da177e4 144{
a1fa4cdc
JD
145 struct i2c_adapter *adapter = client->adapter;
146 u16 man_id;
147 u8 chip_id;
1da177e4
LT
148
149 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
dc18a418 150 return -ENODEV;
1da177e4 151
a1fa4cdc
JD
152 /* detection */
153 if ((w83l785ts_read_value(client, W83L785TS_REG_CONFIG, 0) & 0x80)
154 || (w83l785ts_read_value(client, W83L785TS_REG_TYPE, 0) & 0xFC)) {
155 dev_dbg(&adapter->dev,
156 "W83L785TS-S detection failed at 0x%02x\n",
157 client->addr);
158 return -ENODEV;
1da177e4
LT
159 }
160
a1fa4cdc
JD
161 /* Identification */
162 man_id = (w83l785ts_read_value(client, W83L785TS_REG_MAN_ID1, 0) << 8)
163 + w83l785ts_read_value(client, W83L785TS_REG_MAN_ID2, 0);
164 chip_id = w83l785ts_read_value(client, W83L785TS_REG_CHIP_ID, 0);
165
166 if (man_id != 0x5CA3 /* Winbond */
167 || chip_id != 0x70) { /* W83L785TS-S */
168 dev_dbg(&adapter->dev,
169 "Unsupported chip (man_id=0x%04X, chip_id=0x%02X)\n",
170 man_id, chip_id);
171 return -ENODEV;
1da177e4
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172 }
173
dc18a418
JD
174 strlcpy(info->type, "w83l785ts", I2C_NAME_SIZE);
175
176 return 0;
177}
178
f187fc04 179static int w83l785ts_probe(struct i2c_client *client,
dc18a418
JD
180 const struct i2c_device_id *id)
181{
182 struct w83l785ts_data *data;
f187fc04 183 struct device *dev = &client->dev;
dc18a418
JD
184 int err = 0;
185
186 data = kzalloc(sizeof(struct w83l785ts_data), GFP_KERNEL);
187 if (!data) {
188 err = -ENOMEM;
189 goto exit;
190 }
191
f187fc04 192 i2c_set_clientdata(client, data);
1da177e4 193 data->valid = 0;
9a61bf63 194 mutex_init(&data->update_lock);
1da177e4
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195
196 /* Default values in case the first read fails (unlikely). */
709439a2 197 data->temp[1] = data->temp[0] = 0;
1da177e4 198
1da177e4
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199 /*
200 * Initialize the W83L785TS chip
201 * Nothing yet, assume it is already started.
202 */
203
f187fc04 204 err = device_create_file(dev, &sensor_dev_attr_temp1_input.dev_attr);
ccc5c306
RM
205 if (err)
206 goto exit_remove;
207
f187fc04 208 err = device_create_file(dev, &sensor_dev_attr_temp1_max.dev_attr);
ccc5c306
RM
209 if (err)
210 goto exit_remove;
211
1da177e4 212 /* Register sysfs hooks */
f187fc04 213 data->hwmon_dev = hwmon_device_register(dev);
1beeffe4
TJ
214 if (IS_ERR(data->hwmon_dev)) {
215 err = PTR_ERR(data->hwmon_dev);
ccc5c306 216 goto exit_remove;
943b0830
MH
217 }
218
1da177e4
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219 return 0;
220
ccc5c306 221exit_remove:
f187fc04
GR
222 device_remove_file(dev, &sensor_dev_attr_temp1_input.dev_attr);
223 device_remove_file(dev, &sensor_dev_attr_temp1_max.dev_attr);
1da177e4
LT
224 kfree(data);
225exit:
226 return err;
227}
228
dc18a418 229static int w83l785ts_remove(struct i2c_client *client)
1da177e4 230{
943b0830 231 struct w83l785ts_data *data = i2c_get_clientdata(client);
1da177e4 232
1beeffe4 233 hwmon_device_unregister(data->hwmon_dev);
ccc5c306
RM
234 device_remove_file(&client->dev,
235 &sensor_dev_attr_temp1_input.dev_attr);
236 device_remove_file(&client->dev,
237 &sensor_dev_attr_temp1_max.dev_attr);
1da177e4 238
943b0830 239 kfree(data);
1da177e4
LT
240 return 0;
241}
242
243static u8 w83l785ts_read_value(struct i2c_client *client, u8 reg, u8 defval)
244{
245 int value, i;
dc18a418
JD
246 struct device *dev;
247 const char *prefix;
248
130067d7
GR
249 /*
250 * We might be called during detection, at which point the client
251 * isn't yet fully initialized, so we can't use dev_dbg on it
252 */
dc18a418
JD
253 if (i2c_get_clientdata(client)) {
254 dev = &client->dev;
255 prefix = "";
256 } else {
257 dev = &client->adapter->dev;
258 prefix = "w83l785ts: ";
259 }
1da177e4 260
130067d7
GR
261 /*
262 * Frequent read errors have been reported on Asus boards, so we
1da177e4 263 * retry on read errors. If it still fails (unlikely), return the
130067d7
GR
264 * default value requested by the caller.
265 */
1da177e4
LT
266 for (i = 1; i <= MAX_RETRIES; i++) {
267 value = i2c_smbus_read_byte_data(client, reg);
268 if (value >= 0) {
dc18a418
JD
269 dev_dbg(dev, "%sRead 0x%02x from register 0x%02x.\n",
270 prefix, value, reg);
1da177e4
LT
271 return value;
272 }
dc18a418 273 dev_dbg(dev, "%sRead failed, will retry in %d.\n", prefix, i);
1da177e4
LT
274 msleep(i);
275 }
276
dc18a418 277 dev_err(dev, "%sCouldn't read value from register 0x%02x.\n", prefix,
4040c415 278 reg);
1da177e4
LT
279 return defval;
280}
281
282static struct w83l785ts_data *w83l785ts_update_device(struct device *dev)
283{
284 struct i2c_client *client = to_i2c_client(dev);
285 struct w83l785ts_data *data = i2c_get_clientdata(client);
286
9a61bf63 287 mutex_lock(&data->update_lock);
1da177e4
LT
288
289 if (!data->valid || time_after(jiffies, data->last_updated + HZ * 2)) {
290 dev_dbg(&client->dev, "Updating w83l785ts data.\n");
709439a2
JD
291 data->temp[0] = w83l785ts_read_value(client,
292 W83L785TS_REG_TEMP, data->temp[0]);
293 data->temp[1] = w83l785ts_read_value(client,
294 W83L785TS_REG_TEMP_OVER, data->temp[1]);
1da177e4
LT
295
296 data->last_updated = jiffies;
297 data->valid = 1;
298 }
299
9a61bf63 300 mutex_unlock(&data->update_lock);
1da177e4
LT
301
302 return data;
303}
304
f0967eea 305module_i2c_driver(w83l785ts_driver);
1da177e4
LT
306
307MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>");
308MODULE_DESCRIPTION("W83L785TS-S driver");
309MODULE_LICENSE("GPL");