2 * lm77.c - Part of lm_sensors, Linux kernel modules for hardware
5 * Copyright (c) 2004 Andras BALI <drewie@freemail.hu>
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
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.
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.
24 #include <linux/module.h>
25 #include <linux/init.h>
26 #include <linux/slab.h>
27 #include <linux/jiffies.h>
28 #include <linux/i2c.h>
29 #include <linux/hwmon.h>
30 #include <linux/hwmon-sysfs.h>
31 #include <linux/err.h>
32 #include <linux/mutex.h>
34 /* Addresses to scan */
35 static const unsigned short normal_i2c
[] = { 0x48, 0x49, 0x4a, 0x4b,
38 /* The LM77 registers */
39 #define LM77_REG_TEMP 0x00
40 #define LM77_REG_CONF 0x01
41 #define LM77_REG_TEMP_HYST 0x02
42 #define LM77_REG_TEMP_CRIT 0x03
43 #define LM77_REG_TEMP_MIN 0x04
44 #define LM77_REG_TEMP_MAX 0x05
55 static const u8 temp_regs
[t_num_temp
] = {
56 [t_input
] = LM77_REG_TEMP
,
57 [t_min
] = LM77_REG_TEMP_MIN
,
58 [t_max
] = LM77_REG_TEMP_MAX
,
59 [t_crit
] = LM77_REG_TEMP_CRIT
,
60 [t_hyst
] = LM77_REG_TEMP_HYST
,
63 /* Each client has this additional data */
65 struct i2c_client
*client
;
66 struct mutex update_lock
;
68 unsigned long last_updated
; /* In jiffies */
69 int temp
[t_num_temp
]; /* index using temp_index */
73 /* straight from the datasheet */
74 #define LM77_TEMP_MIN (-55000)
75 #define LM77_TEMP_MAX 125000
78 * In the temperature registers, the low 3 bits are not part of the
79 * temperature values; they are the status bits.
81 static inline s16
LM77_TEMP_TO_REG(int temp
)
83 int ntemp
= clamp_val(temp
, LM77_TEMP_MIN
, LM77_TEMP_MAX
);
84 return (ntemp
/ 500) * 8;
87 static inline int LM77_TEMP_FROM_REG(s16 reg
)
89 return (reg
/ 8) * 500;
93 * All registers are word-sized, except for the configuration register.
94 * The LM77 uses the high-byte first convention.
96 static u16
lm77_read_value(struct i2c_client
*client
, u8 reg
)
98 if (reg
== LM77_REG_CONF
)
99 return i2c_smbus_read_byte_data(client
, reg
);
101 return i2c_smbus_read_word_swapped(client
, reg
);
104 static int lm77_write_value(struct i2c_client
*client
, u8 reg
, u16 value
)
106 if (reg
== LM77_REG_CONF
)
107 return i2c_smbus_write_byte_data(client
, reg
, value
);
109 return i2c_smbus_write_word_swapped(client
, reg
, value
);
112 static struct lm77_data
*lm77_update_device(struct device
*dev
)
114 struct lm77_data
*data
= dev_get_drvdata(dev
);
115 struct i2c_client
*client
= data
->client
;
118 mutex_lock(&data
->update_lock
);
120 if (time_after(jiffies
, data
->last_updated
+ HZ
+ HZ
/ 2)
122 dev_dbg(&client
->dev
, "Starting lm77 update\n");
123 for (i
= 0; i
< t_num_temp
; i
++) {
125 LM77_TEMP_FROM_REG(lm77_read_value(client
,
129 lm77_read_value(client
, LM77_REG_TEMP
) & 0x0007;
130 data
->last_updated
= jiffies
;
134 mutex_unlock(&data
->update_lock
);
141 static ssize_t
show_temp(struct device
*dev
, struct device_attribute
*devattr
,
144 struct sensor_device_attribute
*attr
= to_sensor_dev_attr(devattr
);
145 struct lm77_data
*data
= lm77_update_device(dev
);
147 return sprintf(buf
, "%d\n", data
->temp
[attr
->index
]);
150 static ssize_t
show_temp_hyst(struct device
*dev
,
151 struct device_attribute
*devattr
, char *buf
)
153 struct sensor_device_attribute
*attr
= to_sensor_dev_attr(devattr
);
154 struct lm77_data
*data
= lm77_update_device(dev
);
155 int nr
= attr
->index
;
158 temp
= nr
== t_min
? data
->temp
[nr
] + data
->temp
[t_hyst
] :
159 data
->temp
[nr
] - data
->temp
[t_hyst
];
161 return sprintf(buf
, "%d\n", temp
);
164 static ssize_t
set_temp(struct device
*dev
, struct device_attribute
*devattr
,
165 const char *buf
, size_t count
)
167 struct sensor_device_attribute
*attr
= to_sensor_dev_attr(devattr
);
168 struct lm77_data
*data
= dev_get_drvdata(dev
);
169 struct i2c_client
*client
= data
->client
;
170 int nr
= attr
->index
;
174 err
= kstrtol(buf
, 10, &val
);
178 mutex_lock(&data
->update_lock
);
179 data
->temp
[nr
] = val
;
180 lm77_write_value(client
, temp_regs
[nr
], LM77_TEMP_TO_REG(val
));
181 mutex_unlock(&data
->update_lock
);
186 * hysteresis is stored as a relative value on the chip, so it has to be
189 static ssize_t
set_temp_hyst(struct device
*dev
,
190 struct device_attribute
*devattr
,
191 const char *buf
, size_t count
)
193 struct lm77_data
*data
= dev_get_drvdata(dev
);
194 struct i2c_client
*client
= data
->client
;
198 err
= kstrtoul(buf
, 10, &val
);
202 mutex_lock(&data
->update_lock
);
203 data
->temp
[t_hyst
] = data
->temp
[t_crit
] - val
;
204 lm77_write_value(client
, LM77_REG_TEMP_HYST
,
205 LM77_TEMP_TO_REG(data
->temp
[t_hyst
]));
206 mutex_unlock(&data
->update_lock
);
210 static ssize_t
show_alarm(struct device
*dev
, struct device_attribute
*attr
,
213 int bitnr
= to_sensor_dev_attr(attr
)->index
;
214 struct lm77_data
*data
= lm77_update_device(dev
);
215 return sprintf(buf
, "%u\n", (data
->alarms
>> bitnr
) & 1);
218 static SENSOR_DEVICE_ATTR(temp1_input
, S_IRUGO
, show_temp
, NULL
, t_input
);
219 static SENSOR_DEVICE_ATTR(temp1_crit
, S_IWUSR
| S_IRUGO
, show_temp
, set_temp
,
221 static SENSOR_DEVICE_ATTR(temp1_min
, S_IWUSR
| S_IRUGO
, show_temp
, set_temp
,
223 static SENSOR_DEVICE_ATTR(temp1_max
, S_IWUSR
| S_IRUGO
, show_temp
, set_temp
,
226 static SENSOR_DEVICE_ATTR(temp1_crit_hyst
, S_IWUSR
| S_IRUGO
, show_temp_hyst
,
227 set_temp_hyst
, t_crit
);
228 static SENSOR_DEVICE_ATTR(temp1_min_hyst
, S_IRUGO
, show_temp_hyst
, NULL
, t_min
);
229 static SENSOR_DEVICE_ATTR(temp1_max_hyst
, S_IRUGO
, show_temp_hyst
, NULL
, t_max
);
231 static SENSOR_DEVICE_ATTR(temp1_crit_alarm
, S_IRUGO
, show_alarm
, NULL
, 2);
232 static SENSOR_DEVICE_ATTR(temp1_min_alarm
, S_IRUGO
, show_alarm
, NULL
, 0);
233 static SENSOR_DEVICE_ATTR(temp1_max_alarm
, S_IRUGO
, show_alarm
, NULL
, 1);
235 static struct attribute
*lm77_attrs
[] = {
236 &sensor_dev_attr_temp1_input
.dev_attr
.attr
,
237 &sensor_dev_attr_temp1_crit
.dev_attr
.attr
,
238 &sensor_dev_attr_temp1_min
.dev_attr
.attr
,
239 &sensor_dev_attr_temp1_max
.dev_attr
.attr
,
240 &sensor_dev_attr_temp1_crit_hyst
.dev_attr
.attr
,
241 &sensor_dev_attr_temp1_min_hyst
.dev_attr
.attr
,
242 &sensor_dev_attr_temp1_max_hyst
.dev_attr
.attr
,
243 &sensor_dev_attr_temp1_crit_alarm
.dev_attr
.attr
,
244 &sensor_dev_attr_temp1_min_alarm
.dev_attr
.attr
,
245 &sensor_dev_attr_temp1_max_alarm
.dev_attr
.attr
,
248 ATTRIBUTE_GROUPS(lm77
);
250 /* Return 0 if detection is successful, -ENODEV otherwise */
251 static int lm77_detect(struct i2c_client
*client
, struct i2c_board_info
*info
)
253 struct i2c_adapter
*adapter
= client
->adapter
;
254 int i
, cur
, conf
, hyst
, crit
, min
, max
;
256 if (!i2c_check_functionality(adapter
, I2C_FUNC_SMBUS_BYTE_DATA
|
257 I2C_FUNC_SMBUS_WORD_DATA
))
261 * Here comes the remaining detection. Since the LM77 has no
262 * register dedicated to identification, we have to rely on the
265 * 1. the high 4 bits represent the sign and thus they should
267 * 2. the high 3 bits are unused in the configuration register
268 * 3. addresses 0x06 and 0x07 return the last read value
269 * 4. registers cycling over 8-address boundaries
271 * Word-sized registers are high-byte first.
274 /* addresses cycling */
275 cur
= i2c_smbus_read_word_data(client
, 0);
276 conf
= i2c_smbus_read_byte_data(client
, 1);
277 hyst
= i2c_smbus_read_word_data(client
, 2);
278 crit
= i2c_smbus_read_word_data(client
, 3);
279 min
= i2c_smbus_read_word_data(client
, 4);
280 max
= i2c_smbus_read_word_data(client
, 5);
281 for (i
= 8; i
<= 0xff; i
+= 8) {
282 if (i2c_smbus_read_byte_data(client
, i
+ 1) != conf
283 || i2c_smbus_read_word_data(client
, i
+ 2) != hyst
284 || i2c_smbus_read_word_data(client
, i
+ 3) != crit
285 || i2c_smbus_read_word_data(client
, i
+ 4) != min
286 || i2c_smbus_read_word_data(client
, i
+ 5) != max
)
291 if (((cur
& 0x00f0) != 0xf0 && (cur
& 0x00f0) != 0x0)
292 || ((hyst
& 0x00f0) != 0xf0 && (hyst
& 0x00f0) != 0x0)
293 || ((crit
& 0x00f0) != 0xf0 && (crit
& 0x00f0) != 0x0)
294 || ((min
& 0x00f0) != 0xf0 && (min
& 0x00f0) != 0x0)
295 || ((max
& 0x00f0) != 0xf0 && (max
& 0x00f0) != 0x0))
302 /* 0x06 and 0x07 return the last read value */
303 cur
= i2c_smbus_read_word_data(client
, 0);
304 if (i2c_smbus_read_word_data(client
, 6) != cur
305 || i2c_smbus_read_word_data(client
, 7) != cur
)
307 hyst
= i2c_smbus_read_word_data(client
, 2);
308 if (i2c_smbus_read_word_data(client
, 6) != hyst
309 || i2c_smbus_read_word_data(client
, 7) != hyst
)
311 min
= i2c_smbus_read_word_data(client
, 4);
312 if (i2c_smbus_read_word_data(client
, 6) != min
313 || i2c_smbus_read_word_data(client
, 7) != min
)
316 strlcpy(info
->type
, "lm77", I2C_NAME_SIZE
);
321 static void lm77_init_client(struct i2c_client
*client
)
323 /* Initialize the LM77 chip - turn off shutdown mode */
324 int conf
= lm77_read_value(client
, LM77_REG_CONF
);
326 lm77_write_value(client
, LM77_REG_CONF
, conf
& 0xfe);
329 static int lm77_probe(struct i2c_client
*client
, const struct i2c_device_id
*id
)
331 struct device
*dev
= &client
->dev
;
332 struct device
*hwmon_dev
;
333 struct lm77_data
*data
;
335 data
= devm_kzalloc(dev
, sizeof(struct lm77_data
), GFP_KERNEL
);
339 data
->client
= client
;
340 mutex_init(&data
->update_lock
);
342 /* Initialize the LM77 chip */
343 lm77_init_client(client
);
345 hwmon_dev
= devm_hwmon_device_register_with_groups(dev
, client
->name
,
347 return PTR_ERR_OR_ZERO(hwmon_dev
);
350 static const struct i2c_device_id lm77_id
[] = {
354 MODULE_DEVICE_TABLE(i2c
, lm77_id
);
356 /* This is the driver that will be inserted */
357 static struct i2c_driver lm77_driver
= {
358 .class = I2C_CLASS_HWMON
,
364 .detect
= lm77_detect
,
365 .address_list
= normal_i2c
,
368 module_i2c_driver(lm77_driver
);
370 MODULE_AUTHOR("Andras BALI <drewie@freemail.hu>");
371 MODULE_DESCRIPTION("LM77 driver");
372 MODULE_LICENSE("GPL");