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>
34 * This driver handles the LM75 and compatible digital temperature sensors.
37 enum lm75_type
{ /* keep sorted in alphabetical order */
55 /* Addresses scanned */
56 static const unsigned short normal_i2c
[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c,
57 0x4d, 0x4e, 0x4f, I2C_CLIENT_END
};
60 /* The LM75 registers */
61 #define LM75_REG_CONF 0x01
62 static const u8 LM75_REG_TEMP
[3] = {
68 /* Each client has this additional data */
70 struct device
*hwmon_dev
;
71 struct mutex update_lock
;
73 char valid
; /* !=0 if registers are valid */
74 unsigned long last_updated
; /* In jiffies */
75 u16 temp
[3]; /* Register values,
81 static int lm75_read_value(struct i2c_client
*client
, u8 reg
);
82 static int lm75_write_value(struct i2c_client
*client
, u8 reg
, u16 value
);
83 static struct lm75_data
*lm75_update_device(struct device
*dev
);
86 /*-----------------------------------------------------------------------*/
88 /* sysfs attributes for hwmon */
90 static ssize_t
show_temp(struct device
*dev
, struct device_attribute
*da
,
93 struct sensor_device_attribute
*attr
= to_sensor_dev_attr(da
);
94 struct lm75_data
*data
= lm75_update_device(dev
);
95 return sprintf(buf
, "%d\n",
96 LM75_TEMP_FROM_REG(data
->temp
[attr
->index
]));
99 static ssize_t
set_temp(struct device
*dev
, struct device_attribute
*da
,
100 const char *buf
, size_t count
)
102 struct sensor_device_attribute
*attr
= to_sensor_dev_attr(da
);
103 struct i2c_client
*client
= to_i2c_client(dev
);
104 struct lm75_data
*data
= i2c_get_clientdata(client
);
105 int nr
= attr
->index
;
106 long temp
= simple_strtol(buf
, NULL
, 10);
108 mutex_lock(&data
->update_lock
);
109 data
->temp
[nr
] = LM75_TEMP_TO_REG(temp
);
110 lm75_write_value(client
, LM75_REG_TEMP
[nr
], data
->temp
[nr
]);
111 mutex_unlock(&data
->update_lock
);
115 static SENSOR_DEVICE_ATTR(temp1_max
, S_IWUSR
| S_IRUGO
,
116 show_temp
, set_temp
, 1);
117 static SENSOR_DEVICE_ATTR(temp1_max_hyst
, S_IWUSR
| S_IRUGO
,
118 show_temp
, set_temp
, 2);
119 static SENSOR_DEVICE_ATTR(temp1_input
, S_IRUGO
, show_temp
, NULL
, 0);
121 static struct attribute
*lm75_attributes
[] = {
122 &sensor_dev_attr_temp1_input
.dev_attr
.attr
,
123 &sensor_dev_attr_temp1_max
.dev_attr
.attr
,
124 &sensor_dev_attr_temp1_max_hyst
.dev_attr
.attr
,
129 static const struct attribute_group lm75_group
= {
130 .attrs
= lm75_attributes
,
133 /*-----------------------------------------------------------------------*/
135 /* device probe and removal */
138 lm75_probe(struct i2c_client
*client
, const struct i2c_device_id
*id
)
140 struct lm75_data
*data
;
142 u8 set_mask
, clr_mask
;
145 if (!i2c_check_functionality(client
->adapter
,
146 I2C_FUNC_SMBUS_BYTE_DATA
| I2C_FUNC_SMBUS_WORD_DATA
))
149 data
= kzalloc(sizeof(struct lm75_data
), GFP_KERNEL
);
153 i2c_set_clientdata(client
, data
);
154 mutex_init(&data
->update_lock
);
156 /* Set to LM75 resolution (9 bits, 1/2 degree C) and range.
157 * Then tweak to be more precise when appropriate.
160 clr_mask
= (1 << 0) /* continuous conversions */
161 | (1 << 6) | (1 << 5); /* 9-bit mode */
163 /* configure as specified */
164 status
= lm75_read_value(client
, LM75_REG_CONF
);
166 dev_dbg(&client
->dev
, "Can't read config? %d\n", status
);
169 data
->orig_conf
= status
;
170 new = status
& ~clr_mask
;
173 lm75_write_value(client
, LM75_REG_CONF
, new);
174 dev_dbg(&client
->dev
, "Config %02x\n", new);
176 /* Register sysfs hooks */
177 status
= sysfs_create_group(&client
->dev
.kobj
, &lm75_group
);
181 data
->hwmon_dev
= hwmon_device_register(&client
->dev
);
182 if (IS_ERR(data
->hwmon_dev
)) {
183 status
= PTR_ERR(data
->hwmon_dev
);
187 dev_info(&client
->dev
, "%s: sensor '%s'\n",
188 dev_name(data
->hwmon_dev
), client
->name
);
193 sysfs_remove_group(&client
->dev
.kobj
, &lm75_group
);
195 i2c_set_clientdata(client
, NULL
);
200 static int lm75_remove(struct i2c_client
*client
)
202 struct lm75_data
*data
= i2c_get_clientdata(client
);
204 hwmon_device_unregister(data
->hwmon_dev
);
205 sysfs_remove_group(&client
->dev
.kobj
, &lm75_group
);
206 lm75_write_value(client
, LM75_REG_CONF
, data
->orig_conf
);
207 i2c_set_clientdata(client
, NULL
);
212 static const struct i2c_device_id lm75_ids
[] = {
213 { "ds1775", ds1775
, },
217 { "max6625", max6625
, },
218 { "max6626", max6626
, },
219 { "mcp980x", mcp980x
, },
220 { "stds75", stds75
, },
222 { "tmp100", tmp100
, },
223 { "tmp101", tmp101
, },
224 { "tmp105", tmp105
, },
225 { "tmp175", tmp175
, },
226 { "tmp275", tmp275
, },
230 MODULE_DEVICE_TABLE(i2c
, lm75_ids
);
232 /* Return 0 if detection is successful, -ENODEV otherwise */
233 static int lm75_detect(struct i2c_client
*new_client
,
234 struct i2c_board_info
*info
)
236 struct i2c_adapter
*adapter
= new_client
->adapter
;
238 int cur
, conf
, hyst
, os
;
240 if (!i2c_check_functionality(adapter
, I2C_FUNC_SMBUS_BYTE_DATA
|
241 I2C_FUNC_SMBUS_WORD_DATA
))
244 /* Now, we do the remaining detection. There is no identification-
245 dedicated register so we have to rely on several tricks:
246 unused bits, registers cycling over 8-address boundaries,
247 addresses 0x04-0x07 returning the last read value.
248 The cycling+unused addresses combination is not tested,
249 since it would significantly slow the detection down and would
250 hardly add any value. */
252 /* Unused addresses */
253 cur
= i2c_smbus_read_word_data(new_client
, 0);
254 conf
= i2c_smbus_read_byte_data(new_client
, 1);
255 hyst
= i2c_smbus_read_word_data(new_client
, 2);
256 if (i2c_smbus_read_word_data(new_client
, 4) != hyst
257 || i2c_smbus_read_word_data(new_client
, 5) != hyst
258 || i2c_smbus_read_word_data(new_client
, 6) != hyst
259 || i2c_smbus_read_word_data(new_client
, 7) != hyst
)
261 os
= i2c_smbus_read_word_data(new_client
, 3);
262 if (i2c_smbus_read_word_data(new_client
, 4) != os
263 || i2c_smbus_read_word_data(new_client
, 5) != os
264 || i2c_smbus_read_word_data(new_client
, 6) != os
265 || i2c_smbus_read_word_data(new_client
, 7) != os
)
272 /* Addresses cycling */
273 for (i
= 8; i
< 0xff; i
+= 8) {
274 if (i2c_smbus_read_byte_data(new_client
, i
+ 1) != conf
275 || i2c_smbus_read_word_data(new_client
, i
+ 2) != hyst
276 || i2c_smbus_read_word_data(new_client
, i
+ 3) != os
)
280 strlcpy(info
->type
, "lm75", I2C_NAME_SIZE
);
285 static struct i2c_driver lm75_driver
= {
286 .class = I2C_CLASS_HWMON
,
291 .remove
= lm75_remove
,
292 .id_table
= lm75_ids
,
293 .detect
= lm75_detect
,
294 .address_list
= normal_i2c
,
297 /*-----------------------------------------------------------------------*/
299 /* register access */
301 /* All registers are word-sized, except for the configuration register.
302 LM75 uses a high-byte first convention, which is exactly opposite to
303 the SMBus standard. */
304 static int lm75_read_value(struct i2c_client
*client
, u8 reg
)
308 if (reg
== LM75_REG_CONF
)
309 return i2c_smbus_read_byte_data(client
, reg
);
311 value
= i2c_smbus_read_word_data(client
, reg
);
312 return (value
< 0) ? value
: swab16(value
);
315 static int lm75_write_value(struct i2c_client
*client
, u8 reg
, u16 value
)
317 if (reg
== LM75_REG_CONF
)
318 return i2c_smbus_write_byte_data(client
, reg
, value
);
320 return i2c_smbus_write_word_data(client
, reg
, swab16(value
));
323 static struct lm75_data
*lm75_update_device(struct device
*dev
)
325 struct i2c_client
*client
= to_i2c_client(dev
);
326 struct lm75_data
*data
= i2c_get_clientdata(client
);
328 mutex_lock(&data
->update_lock
);
330 if (time_after(jiffies
, data
->last_updated
+ HZ
+ HZ
/ 2)
333 dev_dbg(&client
->dev
, "Starting lm75 update\n");
335 for (i
= 0; i
< ARRAY_SIZE(data
->temp
); i
++) {
338 status
= lm75_read_value(client
, LM75_REG_TEMP
[i
]);
340 dev_dbg(&client
->dev
, "reg %d, err %d\n",
341 LM75_REG_TEMP
[i
], status
);
343 data
->temp
[i
] = status
;
345 data
->last_updated
= jiffies
;
349 mutex_unlock(&data
->update_lock
);
354 /*-----------------------------------------------------------------------*/
358 static int __init
sensors_lm75_init(void)
360 return i2c_add_driver(&lm75_driver
);
363 static void __exit
sensors_lm75_exit(void)
365 i2c_del_driver(&lm75_driver
);
368 MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>");
369 MODULE_DESCRIPTION("LM75 driver");
370 MODULE_LICENSE("GPL");
372 module_init(sensors_lm75_init
);
373 module_exit(sensors_lm75_exit
);