xref: /linux/drivers/hwmon/lm77.c (revision f3d9478b2ce468c3115b02ecae7e975990697f15)
1 /*
2     lm77.c - Part of lm_sensors, Linux kernel modules for hardware
3              monitoring
4 
5     Copyright (c) 2004  Andras BALI <drewie@freemail.hu>
6 
7     Heavily based on lm75.c by Frodo Looijaard <frodol@dds.nl>.  The LM77
8     is a temperature sensor and thermal window comparator with 0.5 deg
9     resolution made by National Semiconductor.  Complete datasheet can be
10     obtained at their site:
11        http://www.national.com/pf/LM/LM77.html
12 
13     This program is free software; you can redistribute it and/or modify
14     it under the terms of the GNU General Public License as published by
15     the Free Software Foundation; either version 2 of the License, or
16     (at your option) any later version.
17 
18     This program is distributed in the hope that it will be useful,
19     but WITHOUT ANY WARRANTY; without even the implied warranty of
20     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
21     GNU General Public License for more details.
22 
23     You should have received a copy of the GNU General Public License
24     along with this program; if not, write to the Free Software
25     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
26 */
27 
28 #include <linux/module.h>
29 #include <linux/init.h>
30 #include <linux/slab.h>
31 #include <linux/jiffies.h>
32 #include <linux/i2c.h>
33 #include <linux/hwmon.h>
34 #include <linux/err.h>
35 #include <linux/mutex.h>
36 
37 /* Addresses to scan */
38 static unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, I2C_CLIENT_END };
39 
40 /* Insmod parameters */
41 I2C_CLIENT_INSMOD_1(lm77);
42 
43 /* The LM77 registers */
44 #define LM77_REG_TEMP		0x00
45 #define LM77_REG_CONF		0x01
46 #define LM77_REG_TEMP_HYST	0x02
47 #define LM77_REG_TEMP_CRIT	0x03
48 #define LM77_REG_TEMP_MIN	0x04
49 #define LM77_REG_TEMP_MAX	0x05
50 
51 /* Each client has this additional data */
52 struct lm77_data {
53 	struct i2c_client	client;
54 	struct class_device *class_dev;
55 	struct mutex		update_lock;
56 	char			valid;
57 	unsigned long		last_updated;	/* In jiffies */
58 	int			temp_input;	/* Temperatures */
59 	int			temp_crit;
60 	int			temp_min;
61 	int			temp_max;
62 	int			temp_hyst;
63 	u8			alarms;
64 };
65 
66 static int lm77_attach_adapter(struct i2c_adapter *adapter);
67 static int lm77_detect(struct i2c_adapter *adapter, int address, int kind);
68 static void lm77_init_client(struct i2c_client *client);
69 static int lm77_detach_client(struct i2c_client *client);
70 static u16 lm77_read_value(struct i2c_client *client, u8 reg);
71 static int lm77_write_value(struct i2c_client *client, u8 reg, u16 value);
72 
73 static struct lm77_data *lm77_update_device(struct device *dev);
74 
75 
76 /* This is the driver that will be inserted */
77 static struct i2c_driver lm77_driver = {
78 	.driver = {
79 		.name	= "lm77",
80 	},
81 	.attach_adapter = lm77_attach_adapter,
82 	.detach_client	= lm77_detach_client,
83 };
84 
85 /* straight from the datasheet */
86 #define LM77_TEMP_MIN (-55000)
87 #define LM77_TEMP_MAX 125000
88 
89 /* In the temperature registers, the low 3 bits are not part of the
90    temperature values; they are the status bits. */
91 static inline s16 LM77_TEMP_TO_REG(int temp)
92 {
93 	int ntemp = SENSORS_LIMIT(temp, LM77_TEMP_MIN, LM77_TEMP_MAX);
94 	return (ntemp / 500) * 8;
95 }
96 
97 static inline int LM77_TEMP_FROM_REG(s16 reg)
98 {
99 	return (reg / 8) * 500;
100 }
101 
102 /* sysfs stuff */
103 
104 /* read routines for temperature limits */
105 #define show(value)	\
106 static ssize_t show_##value(struct device *dev, struct device_attribute *attr, char *buf)	\
107 {								\
108 	struct lm77_data *data = lm77_update_device(dev);	\
109 	return sprintf(buf, "%d\n", data->value);		\
110 }
111 
112 show(temp_input);
113 show(temp_crit);
114 show(temp_min);
115 show(temp_max);
116 show(alarms);
117 
118 /* read routines for hysteresis values */
119 static ssize_t show_temp_crit_hyst(struct device *dev, struct device_attribute *attr, char *buf)
120 {
121 	struct lm77_data *data = lm77_update_device(dev);
122 	return sprintf(buf, "%d\n", data->temp_crit - data->temp_hyst);
123 }
124 static ssize_t show_temp_min_hyst(struct device *dev, struct device_attribute *attr, char *buf)
125 {
126 	struct lm77_data *data = lm77_update_device(dev);
127 	return sprintf(buf, "%d\n", data->temp_min + data->temp_hyst);
128 }
129 static ssize_t show_temp_max_hyst(struct device *dev, struct device_attribute *attr, char *buf)
130 {
131 	struct lm77_data *data = lm77_update_device(dev);
132 	return sprintf(buf, "%d\n", data->temp_max - data->temp_hyst);
133 }
134 
135 /* write routines */
136 #define set(value, reg)	\
137 static ssize_t set_##value(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)	\
138 {										\
139 	struct i2c_client *client = to_i2c_client(dev);				\
140 	struct lm77_data *data = i2c_get_clientdata(client);			\
141 	long val = simple_strtoul(buf, NULL, 10);				\
142 										\
143 	mutex_lock(&data->update_lock);						\
144 	data->value = val;				\
145 	lm77_write_value(client, reg, LM77_TEMP_TO_REG(data->value));		\
146 	mutex_unlock(&data->update_lock);					\
147 	return count;								\
148 }
149 
150 set(temp_min, LM77_REG_TEMP_MIN);
151 set(temp_max, LM77_REG_TEMP_MAX);
152 
153 /* hysteresis is stored as a relative value on the chip, so it has to be
154    converted first */
155 static ssize_t set_temp_crit_hyst(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
156 {
157 	struct i2c_client *client = to_i2c_client(dev);
158 	struct lm77_data *data = i2c_get_clientdata(client);
159 	unsigned long val = simple_strtoul(buf, NULL, 10);
160 
161 	mutex_lock(&data->update_lock);
162 	data->temp_hyst = data->temp_crit - val;
163 	lm77_write_value(client, LM77_REG_TEMP_HYST,
164 			 LM77_TEMP_TO_REG(data->temp_hyst));
165 	mutex_unlock(&data->update_lock);
166 	return count;
167 }
168 
169 /* preserve hysteresis when setting T_crit */
170 static ssize_t set_temp_crit(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
171 {
172 	struct i2c_client *client = to_i2c_client(dev);
173 	struct lm77_data *data = i2c_get_clientdata(client);
174 	long val = simple_strtoul(buf, NULL, 10);
175 	int oldcrithyst;
176 
177 	mutex_lock(&data->update_lock);
178 	oldcrithyst = data->temp_crit - data->temp_hyst;
179 	data->temp_crit = val;
180 	data->temp_hyst = data->temp_crit - oldcrithyst;
181 	lm77_write_value(client, LM77_REG_TEMP_CRIT,
182 			 LM77_TEMP_TO_REG(data->temp_crit));
183 	lm77_write_value(client, LM77_REG_TEMP_HYST,
184 			 LM77_TEMP_TO_REG(data->temp_hyst));
185 	mutex_unlock(&data->update_lock);
186 	return count;
187 }
188 
189 static DEVICE_ATTR(temp1_input, S_IRUGO,
190 		   show_temp_input, NULL);
191 static DEVICE_ATTR(temp1_crit, S_IWUSR | S_IRUGO,
192 		   show_temp_crit, set_temp_crit);
193 static DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO,
194 		   show_temp_min, set_temp_min);
195 static DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO,
196 		   show_temp_max, set_temp_max);
197 
198 static DEVICE_ATTR(temp1_crit_hyst, S_IWUSR | S_IRUGO,
199 		   show_temp_crit_hyst, set_temp_crit_hyst);
200 static DEVICE_ATTR(temp1_min_hyst, S_IRUGO,
201 		   show_temp_min_hyst, NULL);
202 static DEVICE_ATTR(temp1_max_hyst, S_IRUGO,
203 		   show_temp_max_hyst, NULL);
204 
205 static DEVICE_ATTR(alarms, S_IRUGO,
206 		   show_alarms, NULL);
207 
208 static int lm77_attach_adapter(struct i2c_adapter *adapter)
209 {
210 	if (!(adapter->class & I2C_CLASS_HWMON))
211 		return 0;
212 	return i2c_probe(adapter, &addr_data, lm77_detect);
213 }
214 
215 /* This function is called by i2c_probe */
216 static int lm77_detect(struct i2c_adapter *adapter, int address, int kind)
217 {
218 	struct i2c_client *new_client;
219 	struct lm77_data *data;
220 	int err = 0;
221 	const char *name = "";
222 
223 	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
224 				     I2C_FUNC_SMBUS_WORD_DATA))
225 		goto exit;
226 
227 	/* OK. For now, we presume we have a valid client. We now create the
228 	   client structure, even though we cannot fill it completely yet.
229 	   But it allows us to access lm77_{read,write}_value. */
230 	if (!(data = kzalloc(sizeof(struct lm77_data), GFP_KERNEL))) {
231 		err = -ENOMEM;
232 		goto exit;
233 	}
234 
235 	new_client = &data->client;
236 	i2c_set_clientdata(new_client, data);
237 	new_client->addr = address;
238 	new_client->adapter = adapter;
239 	new_client->driver = &lm77_driver;
240 	new_client->flags = 0;
241 
242 	/* Here comes the remaining detection.  Since the LM77 has no
243 	   register dedicated to identification, we have to rely on the
244 	   following tricks:
245 
246 	   1. the high 4 bits represent the sign and thus they should
247 	      always be the same
248 	   2. the high 3 bits are unused in the configuration register
249 	   3. addresses 0x06 and 0x07 return the last read value
250 	   4. registers cycling over 8-address boundaries
251 
252 	   Word-sized registers are high-byte first. */
253 	if (kind < 0) {
254 		int i, cur, conf, hyst, crit, min, max;
255 
256 		/* addresses cycling */
257 		cur = i2c_smbus_read_word_data(new_client, 0);
258 		conf = i2c_smbus_read_byte_data(new_client, 1);
259 		hyst = i2c_smbus_read_word_data(new_client, 2);
260 		crit = i2c_smbus_read_word_data(new_client, 3);
261 		min = i2c_smbus_read_word_data(new_client, 4);
262 		max = i2c_smbus_read_word_data(new_client, 5);
263 		for (i = 8; i <= 0xff; i += 8)
264 			if (i2c_smbus_read_byte_data(new_client, i + 1) != conf
265 			    || i2c_smbus_read_word_data(new_client, i + 2) != hyst
266 			    || i2c_smbus_read_word_data(new_client, i + 3) != crit
267 			    || i2c_smbus_read_word_data(new_client, i + 4) != min
268 			    || i2c_smbus_read_word_data(new_client, i + 5) != max)
269 				goto exit_free;
270 
271 		/* sign bits */
272 		if (((cur & 0x00f0) != 0xf0 && (cur & 0x00f0) != 0x0)
273 		    || ((hyst & 0x00f0) != 0xf0 && (hyst & 0x00f0) != 0x0)
274 		    || ((crit & 0x00f0) != 0xf0 && (crit & 0x00f0) != 0x0)
275 		    || ((min & 0x00f0) != 0xf0 && (min & 0x00f0) != 0x0)
276 		    || ((max & 0x00f0) != 0xf0 && (max & 0x00f0) != 0x0))
277 			goto exit_free;
278 
279 		/* unused bits */
280 		if (conf & 0xe0)
281 			goto exit_free;
282 
283 		/* 0x06 and 0x07 return the last read value */
284 		cur = i2c_smbus_read_word_data(new_client, 0);
285 		if (i2c_smbus_read_word_data(new_client, 6) != cur
286 		    || i2c_smbus_read_word_data(new_client, 7) != cur)
287 			goto exit_free;
288 		hyst = i2c_smbus_read_word_data(new_client, 2);
289 		if (i2c_smbus_read_word_data(new_client, 6) != hyst
290 		    || i2c_smbus_read_word_data(new_client, 7) != hyst)
291 			goto exit_free;
292 		min = i2c_smbus_read_word_data(new_client, 4);
293 		if (i2c_smbus_read_word_data(new_client, 6) != min
294 		    || i2c_smbus_read_word_data(new_client, 7) != min)
295 			goto exit_free;
296 
297 	}
298 
299 	/* Determine the chip type - only one kind supported! */
300 	if (kind <= 0)
301 		kind = lm77;
302 
303 	if (kind == lm77) {
304 		name = "lm77";
305 	}
306 
307 	/* Fill in the remaining client fields and put it into the global list */
308 	strlcpy(new_client->name, name, I2C_NAME_SIZE);
309 	data->valid = 0;
310 	mutex_init(&data->update_lock);
311 
312 	/* Tell the I2C layer a new client has arrived */
313 	if ((err = i2c_attach_client(new_client)))
314 		goto exit_free;
315 
316 	/* Initialize the LM77 chip */
317 	lm77_init_client(new_client);
318 
319 	/* Register sysfs hooks */
320 	data->class_dev = hwmon_device_register(&new_client->dev);
321 	if (IS_ERR(data->class_dev)) {
322 		err = PTR_ERR(data->class_dev);
323 		goto exit_detach;
324 	}
325 
326 	device_create_file(&new_client->dev, &dev_attr_temp1_input);
327 	device_create_file(&new_client->dev, &dev_attr_temp1_crit);
328 	device_create_file(&new_client->dev, &dev_attr_temp1_min);
329 	device_create_file(&new_client->dev, &dev_attr_temp1_max);
330 	device_create_file(&new_client->dev, &dev_attr_temp1_crit_hyst);
331 	device_create_file(&new_client->dev, &dev_attr_temp1_min_hyst);
332 	device_create_file(&new_client->dev, &dev_attr_temp1_max_hyst);
333 	device_create_file(&new_client->dev, &dev_attr_alarms);
334 	return 0;
335 
336 exit_detach:
337 	i2c_detach_client(new_client);
338 exit_free:
339 	kfree(data);
340 exit:
341 	return err;
342 }
343 
344 static int lm77_detach_client(struct i2c_client *client)
345 {
346 	struct lm77_data *data = i2c_get_clientdata(client);
347 	hwmon_device_unregister(data->class_dev);
348 	i2c_detach_client(client);
349 	kfree(data);
350 	return 0;
351 }
352 
353 /* All registers are word-sized, except for the configuration register.
354    The LM77 uses the high-byte first convention. */
355 static u16 lm77_read_value(struct i2c_client *client, u8 reg)
356 {
357 	if (reg == LM77_REG_CONF)
358 		return i2c_smbus_read_byte_data(client, reg);
359 	else
360 		return swab16(i2c_smbus_read_word_data(client, reg));
361 }
362 
363 static int lm77_write_value(struct i2c_client *client, u8 reg, u16 value)
364 {
365 	if (reg == LM77_REG_CONF)
366 		return i2c_smbus_write_byte_data(client, reg, value);
367 	else
368 		return i2c_smbus_write_word_data(client, reg, swab16(value));
369 }
370 
371 static void lm77_init_client(struct i2c_client *client)
372 {
373 	/* Initialize the LM77 chip - turn off shutdown mode */
374 	int conf = lm77_read_value(client, LM77_REG_CONF);
375 	if (conf & 1)
376 		lm77_write_value(client, LM77_REG_CONF, conf & 0xfe);
377 }
378 
379 static struct lm77_data *lm77_update_device(struct device *dev)
380 {
381 	struct i2c_client *client = to_i2c_client(dev);
382 	struct lm77_data *data = i2c_get_clientdata(client);
383 
384 	mutex_lock(&data->update_lock);
385 
386 	if (time_after(jiffies, data->last_updated + HZ + HZ / 2)
387 	    || !data->valid) {
388 		dev_dbg(&client->dev, "Starting lm77 update\n");
389 		data->temp_input =
390 			LM77_TEMP_FROM_REG(lm77_read_value(client,
391 							   LM77_REG_TEMP));
392 		data->temp_hyst =
393 			LM77_TEMP_FROM_REG(lm77_read_value(client,
394 							   LM77_REG_TEMP_HYST));
395 		data->temp_crit =
396 			LM77_TEMP_FROM_REG(lm77_read_value(client,
397 							   LM77_REG_TEMP_CRIT));
398 		data->temp_min =
399 			LM77_TEMP_FROM_REG(lm77_read_value(client,
400 							   LM77_REG_TEMP_MIN));
401 		data->temp_max =
402 			LM77_TEMP_FROM_REG(lm77_read_value(client,
403 							   LM77_REG_TEMP_MAX));
404 		data->alarms =
405 			lm77_read_value(client, LM77_REG_TEMP) & 0x0007;
406 		data->last_updated = jiffies;
407 		data->valid = 1;
408 	}
409 
410 	mutex_unlock(&data->update_lock);
411 
412 	return data;
413 }
414 
415 static int __init sensors_lm77_init(void)
416 {
417 	return i2c_add_driver(&lm77_driver);
418 }
419 
420 static void __exit sensors_lm77_exit(void)
421 {
422 	i2c_del_driver(&lm77_driver);
423 }
424 
425 MODULE_AUTHOR("Andras BALI <drewie@freemail.hu>");
426 MODULE_DESCRIPTION("LM77 driver");
427 MODULE_LICENSE("GPL");
428 
429 module_init(sensors_lm77_init);
430 module_exit(sensors_lm77_exit);
431