xref: /openbmc/linux/drivers/hwmon/w83l785ts.c (revision 9ac8d3fb)
1 /*
2  * w83l785ts.c - Part of lm_sensors, Linux kernel modules for hardware
3  *               monitoring
4  * Copyright (C) 2003-2004  Jean Delvare <khali@linux-fr.org>
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 
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 
52 static const unsigned short normal_i2c[] = { 0x2e, I2C_CLIENT_END };
53 
54 /*
55  * Insmod parameters
56  */
57 
58 I2C_CLIENT_INSMOD_1(w83l785ts);
59 
60 /*
61  * The W83L785TS-S registers
62  * Manufacturer ID is 0x5CA3 for Winbond.
63  */
64 
65 #define W83L785TS_REG_MAN_ID1		0x4D
66 #define W83L785TS_REG_MAN_ID2		0x4C
67 #define W83L785TS_REG_CHIP_ID		0x4E
68 #define W83L785TS_REG_CONFIG		0x40
69 #define W83L785TS_REG_TYPE		0x52
70 #define W83L785TS_REG_TEMP		0x27
71 #define W83L785TS_REG_TEMP_OVER		0x53 /* not sure about this one */
72 
73 /*
74  * Conversions
75  * The W83L785TS-S uses signed 8-bit values.
76  */
77 
78 #define TEMP_FROM_REG(val)	((val) * 1000)
79 
80 /*
81  * Functions declaration
82  */
83 
84 static int w83l785ts_probe(struct i2c_client *client,
85 			   const struct i2c_device_id *id);
86 static int w83l785ts_detect(struct i2c_client *client, int kind,
87 			    struct i2c_board_info *info);
88 static int w83l785ts_remove(struct i2c_client *client);
89 static u8 w83l785ts_read_value(struct i2c_client *client, u8 reg, u8 defval);
90 static struct w83l785ts_data *w83l785ts_update_device(struct device *dev);
91 
92 /*
93  * Driver data (common to all clients)
94  */
95 
96 static const struct i2c_device_id w83l785ts_id[] = {
97 	{ "w83l785ts", w83l785ts },
98 	{ }
99 };
100 MODULE_DEVICE_TABLE(i2c, w83l785ts_id);
101 
102 static struct i2c_driver w83l785ts_driver = {
103 	.class		= I2C_CLASS_HWMON,
104 	.driver = {
105 		.name	= "w83l785ts",
106 	},
107 	.probe		= w83l785ts_probe,
108 	.remove		= w83l785ts_remove,
109 	.id_table	= w83l785ts_id,
110 	.detect		= w83l785ts_detect,
111 	.address_data	= &addr_data,
112 };
113 
114 /*
115  * Client data (each client gets its own)
116  */
117 
118 struct w83l785ts_data {
119 	struct device *hwmon_dev;
120 	struct mutex update_lock;
121 	char valid; /* zero until following fields are valid */
122 	unsigned long last_updated; /* in jiffies */
123 
124 	/* registers values */
125 	s8 temp[2]; /* 0: input
126 		       1: critical limit */
127 };
128 
129 /*
130  * Sysfs stuff
131  */
132 
133 static ssize_t show_temp(struct device *dev, struct device_attribute *devattr,
134 	char *buf)
135 {
136 	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
137 	struct w83l785ts_data *data = w83l785ts_update_device(dev);
138 	return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp[attr->index]));
139 }
140 
141 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0);
142 static SENSOR_DEVICE_ATTR(temp1_max, S_IRUGO, show_temp, NULL, 1);
143 
144 /*
145  * Real code
146  */
147 
148 /* Return 0 if detection is successful, -ENODEV otherwise */
149 static int w83l785ts_detect(struct i2c_client *new_client, int kind,
150 			    struct i2c_board_info *info)
151 {
152 	struct i2c_adapter *adapter = new_client->adapter;
153 
154 	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
155 		return -ENODEV;
156 
157 	/*
158 	 * Now we do the remaining detection. A negative kind means that
159 	 * the driver was loaded with no force parameter (default), so we
160 	 * must both detect and identify the chip (actually there is only
161 	 * one possible kind of chip for now, W83L785TS-S). A zero kind means
162 	 * that the driver was loaded with the force parameter, the detection
163 	 * step shall be skipped. A positive kind means that the driver
164 	 * was loaded with the force parameter and a given kind of chip is
165 	 * requested, so both the detection and the identification steps
166 	 * are skipped.
167 	 */
168 	if (kind < 0) { /* detection */
169 		if (((w83l785ts_read_value(new_client,
170 		      W83L785TS_REG_CONFIG, 0) & 0x80) != 0x00)
171 		 || ((w83l785ts_read_value(new_client,
172 		      W83L785TS_REG_TYPE, 0) & 0xFC) != 0x00)) {
173 			dev_dbg(&adapter->dev,
174 				"W83L785TS-S detection failed at 0x%02x.\n",
175 				new_client->addr);
176 			return -ENODEV;
177 		}
178 	}
179 
180 	if (kind <= 0) { /* identification */
181 		u16 man_id;
182 		u8 chip_id;
183 
184 		man_id = (w83l785ts_read_value(new_client,
185 			 W83L785TS_REG_MAN_ID1, 0) << 8) +
186 			 w83l785ts_read_value(new_client,
187 			 W83L785TS_REG_MAN_ID2, 0);
188 		chip_id = w83l785ts_read_value(new_client,
189 			  W83L785TS_REG_CHIP_ID, 0);
190 
191 		if (man_id == 0x5CA3) { /* Winbond */
192 			if (chip_id == 0x70) { /* W83L785TS-S */
193 				kind = w83l785ts;
194 			}
195 		}
196 
197 		if (kind <= 0) { /* identification failed */
198 			dev_info(&adapter->dev,
199 				 "Unsupported chip (man_id=0x%04X, "
200 				 "chip_id=0x%02X).\n", man_id, chip_id);
201 			return -ENODEV;
202 		}
203 	}
204 
205 	strlcpy(info->type, "w83l785ts", I2C_NAME_SIZE);
206 
207 	return 0;
208 }
209 
210 static int w83l785ts_probe(struct i2c_client *new_client,
211 			   const struct i2c_device_id *id)
212 {
213 	struct w83l785ts_data *data;
214 	int err = 0;
215 
216 	data = kzalloc(sizeof(struct w83l785ts_data), GFP_KERNEL);
217 	if (!data) {
218 		err = -ENOMEM;
219 		goto exit;
220 	}
221 
222 	i2c_set_clientdata(new_client, data);
223 	data->valid = 0;
224 	mutex_init(&data->update_lock);
225 
226 	/* Default values in case the first read fails (unlikely). */
227 	data->temp[1] = data->temp[0] = 0;
228 
229 	/*
230 	 * Initialize the W83L785TS chip
231 	 * Nothing yet, assume it is already started.
232 	 */
233 
234 	err = device_create_file(&new_client->dev,
235 				 &sensor_dev_attr_temp1_input.dev_attr);
236 	if (err)
237 		goto exit_remove;
238 
239 	err = device_create_file(&new_client->dev,
240 				 &sensor_dev_attr_temp1_max.dev_attr);
241 	if (err)
242 		goto exit_remove;
243 
244 	/* Register sysfs hooks */
245 	data->hwmon_dev = hwmon_device_register(&new_client->dev);
246 	if (IS_ERR(data->hwmon_dev)) {
247 		err = PTR_ERR(data->hwmon_dev);
248 		goto exit_remove;
249 	}
250 
251 	return 0;
252 
253 exit_remove:
254 	device_remove_file(&new_client->dev,
255 			   &sensor_dev_attr_temp1_input.dev_attr);
256 	device_remove_file(&new_client->dev,
257 			   &sensor_dev_attr_temp1_max.dev_attr);
258 	kfree(data);
259 exit:
260 	return err;
261 }
262 
263 static int w83l785ts_remove(struct i2c_client *client)
264 {
265 	struct w83l785ts_data *data = i2c_get_clientdata(client);
266 
267 	hwmon_device_unregister(data->hwmon_dev);
268 	device_remove_file(&client->dev,
269 			   &sensor_dev_attr_temp1_input.dev_attr);
270 	device_remove_file(&client->dev,
271 			   &sensor_dev_attr_temp1_max.dev_attr);
272 
273 	kfree(data);
274 	return 0;
275 }
276 
277 static u8 w83l785ts_read_value(struct i2c_client *client, u8 reg, u8 defval)
278 {
279 	int value, i;
280 	struct device *dev;
281 	const char *prefix;
282 
283 	/* We might be called during detection, at which point the client
284 	   isn't yet fully initialized, so we can't use dev_dbg on it */
285 	if (i2c_get_clientdata(client)) {
286 		dev = &client->dev;
287 		prefix = "";
288 	} else {
289 		dev = &client->adapter->dev;
290 		prefix = "w83l785ts: ";
291 	}
292 
293 	/* Frequent read errors have been reported on Asus boards, so we
294 	 * retry on read errors. If it still fails (unlikely), return the
295 	 * default value requested by the caller. */
296 	for (i = 1; i <= MAX_RETRIES; i++) {
297 		value = i2c_smbus_read_byte_data(client, reg);
298 		if (value >= 0) {
299 			dev_dbg(dev, "%sRead 0x%02x from register 0x%02x.\n",
300 				prefix, value, reg);
301 			return value;
302 		}
303 		dev_dbg(dev, "%sRead failed, will retry in %d.\n", prefix, i);
304 		msleep(i);
305 	}
306 
307 	dev_err(dev, "%sCouldn't read value from register 0x%02x.\n", prefix,
308 		reg);
309 	return defval;
310 }
311 
312 static struct w83l785ts_data *w83l785ts_update_device(struct device *dev)
313 {
314 	struct i2c_client *client = to_i2c_client(dev);
315 	struct w83l785ts_data *data = i2c_get_clientdata(client);
316 
317 	mutex_lock(&data->update_lock);
318 
319 	if (!data->valid || time_after(jiffies, data->last_updated + HZ * 2)) {
320 		dev_dbg(&client->dev, "Updating w83l785ts data.\n");
321 		data->temp[0] = w83l785ts_read_value(client,
322 				W83L785TS_REG_TEMP, data->temp[0]);
323 		data->temp[1] = w83l785ts_read_value(client,
324 				W83L785TS_REG_TEMP_OVER, data->temp[1]);
325 
326 		data->last_updated = jiffies;
327 		data->valid = 1;
328 	}
329 
330 	mutex_unlock(&data->update_lock);
331 
332 	return data;
333 }
334 
335 static int __init sensors_w83l785ts_init(void)
336 {
337 	return i2c_add_driver(&w83l785ts_driver);
338 }
339 
340 static void __exit sensors_w83l785ts_exit(void)
341 {
342 	i2c_del_driver(&w83l785ts_driver);
343 }
344 
345 MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>");
346 MODULE_DESCRIPTION("W83L785TS-S driver");
347 MODULE_LICENSE("GPL");
348 
349 module_init(sensors_w83l785ts_init);
350 module_exit(sensors_w83l785ts_exit);
351