1/*
2 * w83l785ts.c - Part of lm_sensors, Linux kernel modules for hardware
3 * monitoring
4 * Copyright (C) 2003-2009 Jean Delvare <jdelvare@suse.de>
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 * <jdelvare@suse.de>.
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
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>
39#include <linux/hwmon.h>
40#include <linux/hwmon-sysfs.h>
41#include <linux/err.h>
42#include <linux/mutex.h>
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
52static const unsigned short normal_i2c[] = { 0x2e, I2C_CLIENT_END };
53
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
72#define TEMP_FROM_REG(val) ((val) * 1000)
73
74/*
75 * Functions declaration
76 */
77
78static int w83l785ts_probe(struct i2c_client *client,
79 const struct i2c_device_id *id);
80static int w83l785ts_detect(struct i2c_client *client,
81 struct i2c_board_info *info);
82static int w83l785ts_remove(struct i2c_client *client);
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 */
89
90static const struct i2c_device_id w83l785ts_id[] = {
91 { "w83l785ts", 0 },
92 { }
93};
94MODULE_DEVICE_TABLE(i2c, w83l785ts_id);
95
96static struct i2c_driver w83l785ts_driver = {
97 .class = I2C_CLASS_HWMON,
98 .driver = {
99 .name = "w83l785ts",
100 },
101 .probe = w83l785ts_probe,
102 .remove = w83l785ts_remove,
103 .id_table = w83l785ts_id,
104 .detect = w83l785ts_detect,
105 .address_list = normal_i2c,
106};
107
108/*
109 * Client data (each client gets its own)
110 */
111
112struct w83l785ts_data {
113 struct device *hwmon_dev;
114 struct mutex update_lock;
115 char valid; /* zero until following fields are valid */
116 unsigned long last_updated; /* in jiffies */
117
118 /* registers values */
119 s8 temp[2]; /* 0: input, 1: critical limit */
120};
121
122/*
123 * Sysfs stuff
124 */
125
126static ssize_t show_temp(struct device *dev, struct device_attribute *devattr,
127 char *buf)
128{
129 struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
130 struct w83l785ts_data *data = w83l785ts_update_device(dev);
131 return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp[attr->index]));
132}
133
134static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0);
135static SENSOR_DEVICE_ATTR(temp1_max, S_IRUGO, show_temp, NULL, 1);
136
137/*
138 * Real code
139 */
140
141/* Return 0 if detection is successful, -ENODEV otherwise */
142static int w83l785ts_detect(struct i2c_client *client,
143 struct i2c_board_info *info)
144{
145 struct i2c_adapter *adapter = client->adapter;
146 u16 man_id;
147 u8 chip_id;
148
149 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
150 return -ENODEV;
151
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;
159 }
160
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;
172 }
173
174 strlcpy(info->type, "w83l785ts", I2C_NAME_SIZE);
175
176 return 0;
177}
178
179static int w83l785ts_probe(struct i2c_client *client,
180 const struct i2c_device_id *id)
181{
182 struct w83l785ts_data *data;
183 struct device *dev = &client->dev;
184 int err;
185
186 data = devm_kzalloc(dev, sizeof(struct w83l785ts_data), GFP_KERNEL);
187 if (!data)
188 return -ENOMEM;
189
190 i2c_set_clientdata(client, data);
191 mutex_init(&data->update_lock);
192
193 /*
194 * Initialize the W83L785TS chip
195 * Nothing yet, assume it is already started.
196 */
197
198 err = device_create_file(dev, &sensor_dev_attr_temp1_input.dev_attr);
199 if (err)
200 return err;
201
202 err = device_create_file(dev, &sensor_dev_attr_temp1_max.dev_attr);
203 if (err)
204 goto exit_remove;
205
206 /* Register sysfs hooks */
207 data->hwmon_dev = hwmon_device_register(dev);
208 if (IS_ERR(data->hwmon_dev)) {
209 err = PTR_ERR(data->hwmon_dev);
210 goto exit_remove;
211 }
212
213 return 0;
214
215exit_remove:
216 device_remove_file(dev, &sensor_dev_attr_temp1_input.dev_attr);
217 device_remove_file(dev, &sensor_dev_attr_temp1_max.dev_attr);
218 return err;
219}
220
221static int w83l785ts_remove(struct i2c_client *client)
222{
223 struct w83l785ts_data *data = i2c_get_clientdata(client);
224
225 hwmon_device_unregister(data->hwmon_dev);
226 device_remove_file(&client->dev,
227 &sensor_dev_attr_temp1_input.dev_attr);
228 device_remove_file(&client->dev,
229 &sensor_dev_attr_temp1_max.dev_attr);
230
231 return 0;
232}
233
234static u8 w83l785ts_read_value(struct i2c_client *client, u8 reg, u8 defval)
235{
236 int value, i;
237 struct device *dev;
238 const char *prefix;
239
240 /*
241 * We might be called during detection, at which point the client
242 * isn't yet fully initialized, so we can't use dev_dbg on it
243 */
244 if (i2c_get_clientdata(client)) {
245 dev = &client->dev;
246 prefix = "";
247 } else {
248 dev = &client->adapter->dev;
249 prefix = "w83l785ts: ";
250 }
251
252 /*
253 * Frequent read errors have been reported on Asus boards, so we
254 * retry on read errors. If it still fails (unlikely), return the
255 * default value requested by the caller.
256 */
257 for (i = 1; i <= MAX_RETRIES; i++) {
258 value = i2c_smbus_read_byte_data(client, reg);
259 if (value >= 0) {
260 dev_dbg(dev, "%sRead 0x%02x from register 0x%02x.\n",
261 prefix, value, reg);
262 return value;
263 }
264 dev_dbg(dev, "%sRead failed, will retry in %d.\n", prefix, i);
265 msleep(i);
266 }
267
268 dev_err(dev, "%sCouldn't read value from register 0x%02x.\n", prefix,
269 reg);
270 return defval;
271}
272
273static struct w83l785ts_data *w83l785ts_update_device(struct device *dev)
274{
275 struct i2c_client *client = to_i2c_client(dev);
276 struct w83l785ts_data *data = i2c_get_clientdata(client);
277
278 mutex_lock(&data->update_lock);
279
280 if (!data->valid || time_after(jiffies, data->last_updated + HZ * 2)) {
281 dev_dbg(&client->dev, "Updating w83l785ts data.\n");
282 data->temp[0] = w83l785ts_read_value(client,
283 W83L785TS_REG_TEMP, data->temp[0]);
284 data->temp[1] = w83l785ts_read_value(client,
285 W83L785TS_REG_TEMP_OVER, data->temp[1]);
286
287 data->last_updated = jiffies;
288 data->valid = 1;
289 }
290
291 mutex_unlock(&data->update_lock);
292
293 return data;
294}
295
296module_i2c_driver(w83l785ts_driver);
297
298MODULE_AUTHOR("Jean Delvare <jdelvare@suse.de>");
299MODULE_DESCRIPTION("W83L785TS-S driver");
300MODULE_LICENSE("GPL");
301