2 * lm92 - Hardware monitoring driver
3 * Copyright (C) 2005-2008 Jean Delvare <jdelvare@suse.de>
5 * Based on the lm90 driver, with some ideas taken from the lm_sensors
8 * The LM92 is a sensor chip made by National Semiconductor. It reports
9 * its own temperature with a 0.0625 deg resolution and a 0.33 deg
10 * accuracy. Complete datasheet can be obtained from National's website
12 * http://www.national.com/pf/LM/LM92.html
14 * This driver also supports the MAX6635 sensor chip made by Maxim.
15 * This chip is compatible with the LM92, but has a lesser accuracy
16 * (1.0 deg). Complete datasheet can be obtained from Maxim's website
18 * http://www.maxim-ic.com/quick_view2.cfm/qv_pk/3074
20 * Since the LM92 was the first chipset supported by this driver, most
21 * comments will refer to this chipset, but are actually general and
22 * concern all supported chipsets, unless mentioned otherwise.
24 * Support could easily be added for the National Semiconductor LM76
25 * and Maxim MAX6633 and MAX6634 chips, which are mostly compatible
28 * This program is free software; you can redistribute it and/or modify
29 * it under the terms of the GNU General Public License as published by
30 * the Free Software Foundation; either version 2 of the License, or
31 * (at your option) any later version.
33 * This program is distributed in the hope that it will be useful,
34 * but WITHOUT ANY WARRANTY; without even the implied warranty of
35 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
36 * GNU General Public License for more details.
39 #include <linux/module.h>
40 #include <linux/init.h>
41 #include <linux/slab.h>
42 #include <linux/i2c.h>
43 #include <linux/hwmon.h>
44 #include <linux/hwmon-sysfs.h>
45 #include <linux/err.h>
46 #include <linux/mutex.h>
47 #include <linux/jiffies.h>
50 * The LM92 and MAX6635 have 2 two-state pins for address selection,
51 * resulting in 4 possible addresses.
53 static const unsigned short normal_i2c
[] = { 0x48, 0x49, 0x4a, 0x4b,
56 /* The LM92 registers */
57 #define LM92_REG_CONFIG 0x01 /* 8-bit, RW */
58 #define LM92_REG_TEMP 0x00 /* 16-bit, RO */
59 #define LM92_REG_TEMP_HYST 0x02 /* 16-bit, RW */
60 #define LM92_REG_TEMP_CRIT 0x03 /* 16-bit, RW */
61 #define LM92_REG_TEMP_LOW 0x04 /* 16-bit, RW */
62 #define LM92_REG_TEMP_HIGH 0x05 /* 16-bit, RW */
63 #define LM92_REG_MAN_ID 0x07 /* 16-bit, RO, LM92 only */
66 * The LM92 uses signed 13-bit values with LSB = 0.0625 degree Celsius,
67 * left-justified in 16-bit registers. No rounding is done, with such
68 * a resolution it's just not worth it. Note that the MAX6635 doesn't
69 * make use of the 4 lower bits for limits (i.e. effective resolution
70 * for limits is 1 degree Celsius).
72 static inline int TEMP_FROM_REG(s16 reg
)
74 return reg
/ 8 * 625 / 10;
77 static inline s16
TEMP_TO_REG(int val
)
80 return -60000 * 10 / 625 * 8;
82 return 160000 * 10 / 625 * 8;
83 return val
* 10 / 625 * 8;
86 /* Alarm flags are stored in the 3 LSB of the temperature register */
87 static inline u8
ALARMS_FROM_REG(s16 reg
)
101 static const u8 regs
[t_num_regs
] = {
102 [t_input
] = LM92_REG_TEMP
,
103 [t_crit
] = LM92_REG_TEMP_CRIT
,
104 [t_min
] = LM92_REG_TEMP_LOW
,
105 [t_max
] = LM92_REG_TEMP_HIGH
,
106 [t_hyst
] = LM92_REG_TEMP_HYST
,
109 /* Client data (each client gets its own) */
111 struct i2c_client
*client
;
112 struct mutex update_lock
;
113 char valid
; /* zero until following fields are valid */
114 unsigned long last_updated
; /* in jiffies */
116 /* registers values */
117 s16 temp
[t_num_regs
]; /* index with enum temp_index */
121 * Sysfs attributes and callback functions
124 static struct lm92_data
*lm92_update_device(struct device
*dev
)
126 struct lm92_data
*data
= dev_get_drvdata(dev
);
127 struct i2c_client
*client
= data
->client
;
130 mutex_lock(&data
->update_lock
);
132 if (time_after(jiffies
, data
->last_updated
+ HZ
)
134 dev_dbg(&client
->dev
, "Updating lm92 data\n");
135 for (i
= 0; i
< t_num_regs
; i
++) {
137 i2c_smbus_read_word_swapped(client
, regs
[i
]);
139 data
->last_updated
= jiffies
;
143 mutex_unlock(&data
->update_lock
);
148 static ssize_t
show_temp(struct device
*dev
, struct device_attribute
*devattr
,
151 struct sensor_device_attribute
*attr
= to_sensor_dev_attr(devattr
);
152 struct lm92_data
*data
= lm92_update_device(dev
);
154 return sprintf(buf
, "%d\n", TEMP_FROM_REG(data
->temp
[attr
->index
]));
157 static ssize_t
set_temp(struct device
*dev
, struct device_attribute
*devattr
,
158 const char *buf
, size_t count
)
160 struct sensor_device_attribute
*attr
= to_sensor_dev_attr(devattr
);
161 struct lm92_data
*data
= dev_get_drvdata(dev
);
162 struct i2c_client
*client
= data
->client
;
163 int nr
= attr
->index
;
167 err
= kstrtol(buf
, 10, &val
);
171 mutex_lock(&data
->update_lock
);
172 data
->temp
[nr
] = TEMP_TO_REG(val
);
173 i2c_smbus_write_word_swapped(client
, regs
[nr
], data
->temp
[nr
]);
174 mutex_unlock(&data
->update_lock
);
178 static ssize_t
show_temp_hyst(struct device
*dev
,
179 struct device_attribute
*devattr
, char *buf
)
181 struct sensor_device_attribute
*attr
= to_sensor_dev_attr(devattr
);
182 struct lm92_data
*data
= lm92_update_device(dev
);
183 return sprintf(buf
, "%d\n", TEMP_FROM_REG(data
->temp
[attr
->index
])
184 - TEMP_FROM_REG(data
->temp
[t_hyst
]));
187 static ssize_t
show_temp_min_hyst(struct device
*dev
,
188 struct device_attribute
*attr
, char *buf
)
190 struct lm92_data
*data
= lm92_update_device(dev
);
191 return sprintf(buf
, "%d\n", TEMP_FROM_REG(data
->temp
[t_min
])
192 + TEMP_FROM_REG(data
->temp
[t_hyst
]));
195 static ssize_t
set_temp_hyst(struct device
*dev
,
196 struct device_attribute
*devattr
,
197 const char *buf
, size_t count
)
199 struct sensor_device_attribute
*attr
= to_sensor_dev_attr(devattr
);
200 struct lm92_data
*data
= dev_get_drvdata(dev
);
201 struct i2c_client
*client
= data
->client
;
205 err
= kstrtol(buf
, 10, &val
);
209 mutex_lock(&data
->update_lock
);
210 data
->temp
[t_hyst
] = TEMP_FROM_REG(data
->temp
[attr
->index
]) - val
;
211 i2c_smbus_write_word_swapped(client
, LM92_REG_TEMP_HYST
,
212 TEMP_TO_REG(data
->temp
[t_hyst
]));
213 mutex_unlock(&data
->update_lock
);
217 static ssize_t
show_alarms(struct device
*dev
, struct device_attribute
*attr
,
220 struct lm92_data
*data
= lm92_update_device(dev
);
221 return sprintf(buf
, "%d\n", ALARMS_FROM_REG(data
->temp
[t_input
]));
224 static ssize_t
show_alarm(struct device
*dev
, struct device_attribute
*attr
,
227 int bitnr
= to_sensor_dev_attr(attr
)->index
;
228 struct lm92_data
*data
= lm92_update_device(dev
);
229 return sprintf(buf
, "%d\n", (data
->temp
[t_input
] >> bitnr
) & 1);
232 static SENSOR_DEVICE_ATTR(temp1_input
, S_IRUGO
, show_temp
, NULL
, t_input
);
233 static SENSOR_DEVICE_ATTR(temp1_crit
, S_IWUSR
| S_IRUGO
, show_temp
, set_temp
,
235 static SENSOR_DEVICE_ATTR(temp1_crit_hyst
, S_IWUSR
| S_IRUGO
, show_temp_hyst
,
236 set_temp_hyst
, t_crit
);
237 static SENSOR_DEVICE_ATTR(temp1_min
, S_IWUSR
| S_IRUGO
, show_temp
, set_temp
,
239 static DEVICE_ATTR(temp1_min_hyst
, S_IRUGO
, show_temp_min_hyst
, NULL
);
240 static SENSOR_DEVICE_ATTR(temp1_max
, S_IWUSR
| S_IRUGO
, show_temp
, set_temp
,
242 static SENSOR_DEVICE_ATTR(temp1_max_hyst
, S_IRUGO
, show_temp_hyst
, NULL
, t_max
);
243 static DEVICE_ATTR(alarms
, S_IRUGO
, show_alarms
, NULL
);
244 static SENSOR_DEVICE_ATTR(temp1_crit_alarm
, S_IRUGO
, show_alarm
, NULL
, 2);
245 static SENSOR_DEVICE_ATTR(temp1_min_alarm
, S_IRUGO
, show_alarm
, NULL
, 0);
246 static SENSOR_DEVICE_ATTR(temp1_max_alarm
, S_IRUGO
, show_alarm
, NULL
, 1);
249 * Detection and registration
252 static void lm92_init_client(struct i2c_client
*client
)
256 /* Start the conversions if needed */
257 config
= i2c_smbus_read_byte_data(client
, LM92_REG_CONFIG
);
259 i2c_smbus_write_byte_data(client
, LM92_REG_CONFIG
,
264 * The MAX6635 has no identification register, so we have to use tricks
265 * to identify it reliably. This is somewhat slow.
266 * Note that we do NOT rely on the 2 MSB of the configuration register
267 * always reading 0, as suggested by the datasheet, because it was once
268 * reported not to be true.
270 static int max6635_check(struct i2c_client
*client
)
272 u16 temp_low
, temp_high
, temp_hyst
, temp_crit
;
277 * No manufacturer ID register, so a read from this address will
278 * always return the last read value.
280 temp_low
= i2c_smbus_read_word_data(client
, LM92_REG_TEMP_LOW
);
281 if (i2c_smbus_read_word_data(client
, LM92_REG_MAN_ID
) != temp_low
)
283 temp_high
= i2c_smbus_read_word_data(client
, LM92_REG_TEMP_HIGH
);
284 if (i2c_smbus_read_word_data(client
, LM92_REG_MAN_ID
) != temp_high
)
287 /* Limits are stored as integer values (signed, 9-bit). */
288 if ((temp_low
& 0x7f00) || (temp_high
& 0x7f00))
290 temp_hyst
= i2c_smbus_read_word_data(client
, LM92_REG_TEMP_HYST
);
291 temp_crit
= i2c_smbus_read_word_data(client
, LM92_REG_TEMP_CRIT
);
292 if ((temp_hyst
& 0x7f00) || (temp_crit
& 0x7f00))
296 * Registers addresses were found to cycle over 16-byte boundaries.
297 * We don't test all registers with all offsets so as to save some
298 * reads and time, but this should still be sufficient to dismiss
301 conf
= i2c_smbus_read_byte_data(client
, LM92_REG_CONFIG
);
302 for (i
= 16; i
< 96; i
*= 2) {
303 if (temp_hyst
!= i2c_smbus_read_word_data(client
,
304 LM92_REG_TEMP_HYST
+ i
- 16)
305 || temp_crit
!= i2c_smbus_read_word_data(client
,
306 LM92_REG_TEMP_CRIT
+ i
)
307 || temp_low
!= i2c_smbus_read_word_data(client
,
308 LM92_REG_TEMP_LOW
+ i
+ 16)
309 || temp_high
!= i2c_smbus_read_word_data(client
,
310 LM92_REG_TEMP_HIGH
+ i
+ 32)
311 || conf
!= i2c_smbus_read_byte_data(client
,
312 LM92_REG_CONFIG
+ i
))
319 static struct attribute
*lm92_attrs
[] = {
320 &sensor_dev_attr_temp1_input
.dev_attr
.attr
,
321 &sensor_dev_attr_temp1_crit
.dev_attr
.attr
,
322 &sensor_dev_attr_temp1_crit_hyst
.dev_attr
.attr
,
323 &sensor_dev_attr_temp1_min
.dev_attr
.attr
,
324 &dev_attr_temp1_min_hyst
.attr
,
325 &sensor_dev_attr_temp1_max
.dev_attr
.attr
,
326 &sensor_dev_attr_temp1_max_hyst
.dev_attr
.attr
,
327 &dev_attr_alarms
.attr
,
328 &sensor_dev_attr_temp1_crit_alarm
.dev_attr
.attr
,
329 &sensor_dev_attr_temp1_min_alarm
.dev_attr
.attr
,
330 &sensor_dev_attr_temp1_max_alarm
.dev_attr
.attr
,
333 ATTRIBUTE_GROUPS(lm92
);
335 /* Return 0 if detection is successful, -ENODEV otherwise */
336 static int lm92_detect(struct i2c_client
*new_client
,
337 struct i2c_board_info
*info
)
339 struct i2c_adapter
*adapter
= new_client
->adapter
;
343 if (!i2c_check_functionality(adapter
, I2C_FUNC_SMBUS_BYTE_DATA
344 | I2C_FUNC_SMBUS_WORD_DATA
))
347 config
= i2c_smbus_read_byte_data(new_client
, LM92_REG_CONFIG
);
348 man_id
= i2c_smbus_read_word_data(new_client
, LM92_REG_MAN_ID
);
350 if ((config
& 0xe0) == 0x00 && man_id
== 0x0180)
351 pr_info("lm92: Found National Semiconductor LM92 chip\n");
352 else if (max6635_check(new_client
))
353 pr_info("lm92: Found Maxim MAX6635 chip\n");
357 strlcpy(info
->type
, "lm92", I2C_NAME_SIZE
);
362 static int lm92_probe(struct i2c_client
*new_client
,
363 const struct i2c_device_id
*id
)
365 struct device
*hwmon_dev
;
366 struct lm92_data
*data
;
368 data
= devm_kzalloc(&new_client
->dev
, sizeof(struct lm92_data
),
373 data
->client
= new_client
;
374 mutex_init(&data
->update_lock
);
376 /* Initialize the chipset */
377 lm92_init_client(new_client
);
379 hwmon_dev
= devm_hwmon_device_register_with_groups(&new_client
->dev
,
382 return PTR_ERR_OR_ZERO(hwmon_dev
);
387 * Module and driver stuff
390 static const struct i2c_device_id lm92_id
[] = {
392 /* max6635 could be added here */
395 MODULE_DEVICE_TABLE(i2c
, lm92_id
);
397 static struct i2c_driver lm92_driver
= {
398 .class = I2C_CLASS_HWMON
,
404 .detect
= lm92_detect
,
405 .address_list
= normal_i2c
,
408 module_i2c_driver(lm92_driver
);
410 MODULE_AUTHOR("Jean Delvare <jdelvare@suse.de>");
411 MODULE_DESCRIPTION("LM92/MAX6635 driver");
412 MODULE_LICENSE("GPL");