2 * lm75.c - Part of lm_sensors, Linux kernel modules for hardware
4 * Copyright (c) 1998, 1999 Frodo Looijaard <frodol@dds.nl>
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
21 #include <linux/module.h>
22 #include <linux/init.h>
23 #include <linux/slab.h>
24 #include <linux/jiffies.h>
25 #include <linux/i2c.h>
26 #include <linux/hwmon.h>
27 #include <linux/hwmon-sysfs.h>
28 #include <linux/err.h>
29 #include <linux/mutex.h>
31 #include <linux/thermal.h>
36 * This driver handles the LM75 and compatible digital temperature sensors.
39 enum lm75_type { /* keep sorted in alphabetical order */
60 /* Addresses scanned */
61 static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c,
62 0x4d, 0x4e, 0x4f, I2C_CLIENT_END };
65 /* The LM75 registers */
66 #define LM75_REG_CONF 0x01
67 static const u8 LM75_REG_TEMP[3] = {
73 /* Each client has this additional data */
75 struct i2c_client *client;
76 struct device *hwmon_dev;
77 struct thermal_zone_device *tz;
78 struct mutex update_lock;
80 u8 resolution; /* In bits, between 9 and 12 */
82 char valid; /* !=0 if registers are valid */
83 unsigned long last_updated; /* In jiffies */
84 unsigned long sample_time; /* In jiffies */
85 s16 temp[3]; /* Register values,
91 static int lm75_read_value(struct i2c_client *client, u8 reg);
92 static int lm75_write_value(struct i2c_client *client, u8 reg, u16 value);
93 static struct lm75_data *lm75_update_device(struct device *dev);
96 /*-----------------------------------------------------------------------*/
98 static inline long lm75_reg_to_mc(s16 temp, u8 resolution)
100 return ((temp >> (16 - resolution)) * 1000) >> (resolution - 8);
103 /* sysfs attributes for hwmon */
105 static int lm75_read_temp(void *dev, long *temp)
107 struct lm75_data *data = lm75_update_device(dev);
110 return PTR_ERR(data);
112 *temp = lm75_reg_to_mc(data->temp[0], data->resolution);
117 static ssize_t show_temp(struct device *dev, struct device_attribute *da,
120 struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
121 struct lm75_data *data = lm75_update_device(dev);
124 return PTR_ERR(data);
126 return sprintf(buf, "%ld\n", lm75_reg_to_mc(data->temp[attr->index],
130 static ssize_t set_temp(struct device *dev, struct device_attribute *da,
131 const char *buf, size_t count)
133 struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
134 struct lm75_data *data = dev_get_drvdata(dev);
135 struct i2c_client *client = data->client;
136 int nr = attr->index;
141 error = kstrtol(buf, 10, &temp);
146 * Resolution of limit registers is assumed to be the same as the
147 * temperature input register resolution unless given explicitly.
149 if (attr->index && data->resolution_limits)
150 resolution = data->resolution_limits;
152 resolution = data->resolution;
154 mutex_lock(&data->update_lock);
155 temp = clamp_val(temp, LM75_TEMP_MIN, LM75_TEMP_MAX);
156 data->temp[nr] = DIV_ROUND_CLOSEST(temp << (resolution - 8),
157 1000) << (16 - resolution);
158 lm75_write_value(client, LM75_REG_TEMP[nr], data->temp[nr]);
159 mutex_unlock(&data->update_lock);
163 static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO,
164 show_temp, set_temp, 1);
165 static SENSOR_DEVICE_ATTR(temp1_max_hyst, S_IWUSR | S_IRUGO,
166 show_temp, set_temp, 2);
167 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0);
169 static struct attribute *lm75_attrs[] = {
170 &sensor_dev_attr_temp1_input.dev_attr.attr,
171 &sensor_dev_attr_temp1_max.dev_attr.attr,
172 &sensor_dev_attr_temp1_max_hyst.dev_attr.attr,
176 ATTRIBUTE_GROUPS(lm75);
178 /*-----------------------------------------------------------------------*/
180 /* device probe and removal */
183 lm75_probe(struct i2c_client *client, const struct i2c_device_id *id)
185 struct device *dev = &client->dev;
186 struct lm75_data *data;
188 u8 set_mask, clr_mask;
190 enum lm75_type kind = id->driver_data;
192 if (!i2c_check_functionality(client->adapter,
193 I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA))
196 data = devm_kzalloc(dev, sizeof(struct lm75_data), GFP_KERNEL);
200 data->client = client;
201 i2c_set_clientdata(client, data);
202 mutex_init(&data->update_lock);
204 /* Set to LM75 resolution (9 bits, 1/2 degree C) and range.
205 * Then tweak to be more precise when appropriate.
208 clr_mask = LM75_SHUTDOWN; /* continuous conversions */
212 clr_mask |= 1 << 5; /* not one-shot mode */
213 data->resolution = 12;
214 data->sample_time = HZ / 8;
220 set_mask |= 2 << 5; /* 11-bit mode */
221 data->resolution = 11;
222 data->sample_time = HZ;
225 set_mask |= 3 << 5; /* 12-bit mode */
226 data->resolution = 12;
227 data->sample_time = HZ / 4;
232 data->resolution = 9;
233 data->sample_time = HZ / 2;
236 data->resolution = 9;
237 data->sample_time = HZ / 4;
240 data->resolution = 12;
241 data->resolution_limits = 9;
242 data->sample_time = HZ / 4;
245 data->resolution = 9;
246 data->sample_time = HZ / 8;
249 data->resolution_limits = 9;
253 set_mask |= 3 << 5; /* 12-bit mode */
254 data->resolution = 12;
255 data->sample_time = HZ;
256 clr_mask |= 1 << 7; /* not one-shot mode */
262 set_mask |= 3 << 5; /* 12-bit mode */
263 clr_mask |= 1 << 7; /* not one-shot mode */
264 data->resolution = 12;
265 data->sample_time = HZ / 2;
269 /* configure as specified */
270 status = lm75_read_value(client, LM75_REG_CONF);
272 dev_dbg(dev, "Can't read config? %d\n", status);
275 data->orig_conf = status;
276 new = status & ~clr_mask;
279 lm75_write_value(client, LM75_REG_CONF, new);
280 dev_dbg(dev, "Config %02x\n", new);
282 data->hwmon_dev = hwmon_device_register_with_groups(dev, client->name,
284 if (IS_ERR(data->hwmon_dev))
285 return PTR_ERR(data->hwmon_dev);
287 data->tz = thermal_zone_of_sensor_register(data->hwmon_dev,
290 lm75_read_temp, NULL);
291 if (IS_ERR(data->tz))
294 dev_info(dev, "%s: sensor '%s'\n",
295 dev_name(data->hwmon_dev), client->name);
300 static int lm75_remove(struct i2c_client *client)
302 struct lm75_data *data = i2c_get_clientdata(client);
304 thermal_zone_of_sensor_unregister(data->hwmon_dev, data->tz);
305 hwmon_device_unregister(data->hwmon_dev);
306 lm75_write_value(client, LM75_REG_CONF, data->orig_conf);
310 static const struct i2c_device_id lm75_ids[] = {
312 { "ds1775", ds1775, },
314 { "ds7505", ds7505, },
318 { "max6625", max6625, },
319 { "max6626", max6626, },
320 { "mcp980x", mcp980x, },
321 { "stds75", stds75, },
323 { "tmp100", tmp100, },
324 { "tmp101", tmp101, },
325 { "tmp105", tmp105, },
326 { "tmp175", tmp175, },
327 { "tmp275", tmp275, },
331 MODULE_DEVICE_TABLE(i2c, lm75_ids);
333 #define LM75A_ID 0xA1
335 /* Return 0 if detection is successful, -ENODEV otherwise */
336 static int lm75_detect(struct i2c_client *new_client,
337 struct i2c_board_info *info)
339 struct i2c_adapter *adapter = new_client->adapter;
344 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
345 I2C_FUNC_SMBUS_WORD_DATA))
349 * Now, we do the remaining detection. There is no identification-
350 * dedicated register so we have to rely on several tricks:
351 * unused bits, registers cycling over 8-address boundaries,
352 * addresses 0x04-0x07 returning the last read value.
353 * The cycling+unused addresses combination is not tested,
354 * since it would significantly slow the detection down and would
355 * hardly add any value.
357 * The National Semiconductor LM75A is different than earlier
358 * LM75s. It has an ID byte of 0xaX (where X is the chip
359 * revision, with 1 being the only revision in existence) in
360 * register 7, and unused registers return 0xff rather than the
363 * Note that this function only detects the original National
364 * Semiconductor LM75 and the LM75A. Clones from other vendors
365 * aren't detected, on purpose, because they are typically never
366 * found on PC hardware. They are found on embedded designs where
367 * they can be instantiated explicitly so detection is not needed.
368 * The absence of identification registers on all these clones
369 * would make their exhaustive detection very difficult and weak,
370 * and odds are that the driver would bind to unsupported devices.
374 conf = i2c_smbus_read_byte_data(new_client, 1);
378 /* First check for LM75A */
379 if (i2c_smbus_read_byte_data(new_client, 7) == LM75A_ID) {
380 /* LM75A returns 0xff on unused registers so
381 just to be sure we check for that too. */
382 if (i2c_smbus_read_byte_data(new_client, 4) != 0xff
383 || i2c_smbus_read_byte_data(new_client, 5) != 0xff
384 || i2c_smbus_read_byte_data(new_client, 6) != 0xff)
387 hyst = i2c_smbus_read_byte_data(new_client, 2);
388 os = i2c_smbus_read_byte_data(new_client, 3);
389 } else { /* Traditional style LM75 detection */
390 /* Unused addresses */
391 hyst = i2c_smbus_read_byte_data(new_client, 2);
392 if (i2c_smbus_read_byte_data(new_client, 4) != hyst
393 || i2c_smbus_read_byte_data(new_client, 5) != hyst
394 || i2c_smbus_read_byte_data(new_client, 6) != hyst
395 || i2c_smbus_read_byte_data(new_client, 7) != hyst)
397 os = i2c_smbus_read_byte_data(new_client, 3);
398 if (i2c_smbus_read_byte_data(new_client, 4) != os
399 || i2c_smbus_read_byte_data(new_client, 5) != os
400 || i2c_smbus_read_byte_data(new_client, 6) != os
401 || i2c_smbus_read_byte_data(new_client, 7) != os)
405 /* Addresses cycling */
406 for (i = 8; i <= 248; i += 40) {
407 if (i2c_smbus_read_byte_data(new_client, i + 1) != conf
408 || i2c_smbus_read_byte_data(new_client, i + 2) != hyst
409 || i2c_smbus_read_byte_data(new_client, i + 3) != os)
411 if (is_lm75a && i2c_smbus_read_byte_data(new_client, i + 7)
416 strlcpy(info->type, is_lm75a ? "lm75a" : "lm75", I2C_NAME_SIZE);
422 static int lm75_suspend(struct device *dev)
425 struct i2c_client *client = to_i2c_client(dev);
426 status = lm75_read_value(client, LM75_REG_CONF);
428 dev_dbg(&client->dev, "Can't read config? %d\n", status);
431 status = status | LM75_SHUTDOWN;
432 lm75_write_value(client, LM75_REG_CONF, status);
436 static int lm75_resume(struct device *dev)
439 struct i2c_client *client = to_i2c_client(dev);
440 status = lm75_read_value(client, LM75_REG_CONF);
442 dev_dbg(&client->dev, "Can't read config? %d\n", status);
445 status = status & ~LM75_SHUTDOWN;
446 lm75_write_value(client, LM75_REG_CONF, status);
450 static const struct dev_pm_ops lm75_dev_pm_ops = {
451 .suspend = lm75_suspend,
452 .resume = lm75_resume,
454 #define LM75_DEV_PM_OPS (&lm75_dev_pm_ops)
456 #define LM75_DEV_PM_OPS NULL
457 #endif /* CONFIG_PM */
459 static struct i2c_driver lm75_driver = {
460 .class = I2C_CLASS_HWMON,
463 .pm = LM75_DEV_PM_OPS,
466 .remove = lm75_remove,
467 .id_table = lm75_ids,
468 .detect = lm75_detect,
469 .address_list = normal_i2c,
472 /*-----------------------------------------------------------------------*/
474 /* register access */
477 * All registers are word-sized, except for the configuration register.
478 * LM75 uses a high-byte first convention, which is exactly opposite to
479 * the SMBus standard.
481 static int lm75_read_value(struct i2c_client *client, u8 reg)
483 if (reg == LM75_REG_CONF)
484 return i2c_smbus_read_byte_data(client, reg);
486 return i2c_smbus_read_word_swapped(client, reg);
489 static int lm75_write_value(struct i2c_client *client, u8 reg, u16 value)
491 if (reg == LM75_REG_CONF)
492 return i2c_smbus_write_byte_data(client, reg, value);
494 return i2c_smbus_write_word_swapped(client, reg, value);
497 static struct lm75_data *lm75_update_device(struct device *dev)
499 struct lm75_data *data = dev_get_drvdata(dev);
500 struct i2c_client *client = data->client;
501 struct lm75_data *ret = data;
503 mutex_lock(&data->update_lock);
505 if (time_after(jiffies, data->last_updated + data->sample_time)
508 dev_dbg(&client->dev, "Starting lm75 update\n");
510 for (i = 0; i < ARRAY_SIZE(data->temp); i++) {
513 status = lm75_read_value(client, LM75_REG_TEMP[i]);
514 if (unlikely(status < 0)) {
516 "LM75: Failed to read value: reg %d, error %d\n",
517 LM75_REG_TEMP[i], status);
518 ret = ERR_PTR(status);
522 data->temp[i] = status;
524 data->last_updated = jiffies;
529 mutex_unlock(&data->update_lock);
533 module_i2c_driver(lm75_driver);
535 MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>");
536 MODULE_DESCRIPTION("LM75 driver");
537 MODULE_LICENSE("GPL");