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.
23 #include <linux/module.h>
24 #include <linux/init.h>
25 #include <linux/slab.h>
26 #include <linux/i2c.h>
27 #include <linux/i2c-sensor.h>
30 /* Addresses to scan */
31 static unsigned short normal_i2c[] = { I2C_CLIENT_END };
32 static unsigned short normal_i2c_range[] = { 0x48, 0x4f, I2C_CLIENT_END };
33 static unsigned int normal_isa[] = { I2C_CLIENT_ISA_END };
34 static unsigned int normal_isa_range[] = { I2C_CLIENT_ISA_END };
36 /* Insmod parameters */
37 SENSORS_INSMOD_1(lm75);
39 /* Many LM75 constants specified below */
41 /* The LM75 registers */
42 #define LM75_REG_TEMP 0x00
43 #define LM75_REG_CONF 0x01
44 #define LM75_REG_TEMP_HYST 0x02
45 #define LM75_REG_TEMP_OS 0x03
47 /* Conversions. Rounding and limit checking is only done on the TO_REG
48 variants. Note that you should be a bit careful with which arguments
49 these macros are called: arguments may be evaluated more than once.
50 Fixing this is just not worth it. */
51 #define TEMP_FROM_REG(val) ((((val & 0x7fff) >> 7) * 5) | ((val & 0x8000)?-256:0))
52 #define TEMP_TO_REG(val) (SENSORS_LIMIT((val<0?(0x200+((val)/5))<<7:(((val) + 2) / 5) << 7),0,0xffff))
55 #define LM75_INIT_TEMP_OS 600
56 #define LM75_INIT_TEMP_HYST 500
58 /* Each client has this additional data */
60 struct semaphore update_lock;
61 char valid; /* !=0 if following fields are valid */
62 unsigned long last_updated; /* In jiffies */
63 u16 temp_input; /* Register values */
68 static int lm75_attach_adapter(struct i2c_adapter *adapter);
69 static int lm75_detect(struct i2c_adapter *adapter, int address, int kind);
70 static void lm75_init_client(struct i2c_client *client);
71 static int lm75_detach_client(struct i2c_client *client);
72 static int lm75_read_value(struct i2c_client *client, u8 reg);
73 static int lm75_write_value(struct i2c_client *client, u8 reg, u16 value);
74 static void lm75_update_client(struct i2c_client *client);
77 /* This is the driver that will be inserted */
78 static struct i2c_driver lm75_driver = {
81 .id = I2C_DRIVERID_LM75,
82 .flags = I2C_DF_NOTIFY,
83 .attach_adapter = lm75_attach_adapter,
84 .detach_client = lm75_detach_client,
87 static int lm75_id = 0;
90 static ssize_t show_##value(struct device *dev, char *buf) \
92 struct i2c_client *client = to_i2c_client(dev); \
93 struct lm75_data *data = i2c_get_clientdata(client); \
96 lm75_update_client(client); \
97 temp = TEMP_FROM_REG(data->value); \
98 return sprintf(buf, "%d\n", temp * 100); \
104 #define set(value, reg) \
105 static ssize_t set_##value(struct device *dev, const char *buf, size_t count) \
107 struct i2c_client *client = to_i2c_client(dev); \
108 struct lm75_data *data = i2c_get_clientdata(client); \
109 int temp = simple_strtoul(buf, NULL, 10) / 100; \
111 data->value = TEMP_TO_REG(temp); \
112 lm75_write_value(client, reg, data->value); \
115 set(temp_max, LM75_REG_TEMP_OS);
116 set(temp_hyst, LM75_REG_TEMP_HYST);
118 static DEVICE_ATTR(temp_max, S_IWUSR | S_IRUGO, show_temp_max, set_temp_max);
119 static DEVICE_ATTR(temp_min, S_IWUSR | S_IRUGO, show_temp_hyst, set_temp_hyst);
120 static DEVICE_ATTR(temp_input, S_IRUGO, show_temp_input, NULL);
122 static int lm75_attach_adapter(struct i2c_adapter *adapter)
124 if (!(adapter->class & I2C_ADAP_CLASS_SMBUS))
126 return i2c_detect(adapter, &addr_data, lm75_detect);
129 /* This function is called by i2c_detect */
130 static int lm75_detect(struct i2c_adapter *adapter, int address, int kind)
132 int i, cur, conf, hyst, os;
133 struct i2c_client *new_client;
134 struct lm75_data *data;
138 /* Make sure we aren't probing the ISA bus!! This is just a safety check
139 at this moment; i2c_detect really won't call us. */
141 if (i2c_is_isa_adapter(adapter)) {
142 dev_dbg(&adapter->dev,
143 "lm75_detect called for an ISA bus adapter?!?\n");
148 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
149 I2C_FUNC_SMBUS_WORD_DATA))
152 /* OK. For now, we presume we have a valid client. We now create the
153 client structure, even though we cannot fill it completely yet.
154 But it allows us to access lm75_{read,write}_value. */
155 if (!(new_client = kmalloc(sizeof(struct i2c_client) +
156 sizeof(struct lm75_data),
161 memset(new_client, 0x00, sizeof(struct i2c_client) +
162 sizeof(struct lm75_data));
164 data = (struct lm75_data *) (new_client + 1);
165 i2c_set_clientdata(new_client, data);
166 new_client->addr = address;
167 new_client->adapter = adapter;
168 new_client->driver = &lm75_driver;
169 new_client->flags = 0;
171 /* Now, we do the remaining detection. It is lousy. */
173 cur = i2c_smbus_read_word_data(new_client, 0);
174 conf = i2c_smbus_read_byte_data(new_client, 1);
175 hyst = i2c_smbus_read_word_data(new_client, 2);
176 os = i2c_smbus_read_word_data(new_client, 3);
177 for (i = 0; i <= 0x1f; i++)
178 if ((i2c_smbus_read_byte_data(new_client, i * 8 + 1) != conf) ||
179 (i2c_smbus_read_word_data(new_client, i * 8 + 2) != hyst) ||
180 (i2c_smbus_read_word_data(new_client, i * 8 + 3) != os))
184 /* Determine the chip type - only one kind supported! */
191 dev_dbg(&adapter->dev, "Internal error: unknown kind (%d)?!?",
196 /* Fill in the remaining client fields and put it into the global list */
197 strlcpy(new_client->dev.name, name, DEVICE_NAME_SIZE);
199 new_client->id = lm75_id++;
201 init_MUTEX(&data->update_lock);
203 /* Tell the I2C layer a new client has arrived */
204 if ((err = i2c_attach_client(new_client)))
207 device_create_file(&new_client->dev, &dev_attr_temp_max);
208 device_create_file(&new_client->dev, &dev_attr_temp_min);
209 device_create_file(&new_client->dev, &dev_attr_temp_input);
211 lm75_init_client(new_client);
220 static int lm75_detach_client(struct i2c_client *client)
222 i2c_detach_client(client);
227 static u16 swap_bytes(u16 val)
229 return (val >> 8) | (val << 8);
232 /* All registers are word-sized, except for the configuration register.
233 LM75 uses a high-byte first convention, which is exactly opposite to
234 the usual practice. */
235 static int lm75_read_value(struct i2c_client *client, u8 reg)
237 if (reg == LM75_REG_CONF)
238 return i2c_smbus_read_byte_data(client, reg);
240 return swap_bytes(i2c_smbus_read_word_data(client, reg));
243 /* All registers are word-sized, except for the configuration register.
244 LM75 uses a high-byte first convention, which is exactly opposite to
245 the usual practice. */
246 static int lm75_write_value(struct i2c_client *client, u8 reg, u16 value)
248 if (reg == LM75_REG_CONF)
249 return i2c_smbus_write_byte_data(client, reg, value);
251 return i2c_smbus_write_word_data(client, reg,
255 static void lm75_init_client(struct i2c_client *client)
257 /* Initialize the LM75 chip */
258 lm75_write_value(client, LM75_REG_TEMP_OS,
259 TEMP_TO_REG(LM75_INIT_TEMP_OS));
260 lm75_write_value(client, LM75_REG_TEMP_HYST,
261 TEMP_TO_REG(LM75_INIT_TEMP_HYST));
262 lm75_write_value(client, LM75_REG_CONF, 0);
265 static void lm75_update_client(struct i2c_client *client)
267 struct lm75_data *data = i2c_get_clientdata(client);
269 down(&data->update_lock);
271 if ((jiffies - data->last_updated > HZ + HZ / 2) ||
272 (jiffies < data->last_updated) || !data->valid) {
273 dev_dbg(&client->dev, "Starting lm75 update\n");
275 data->temp_input = lm75_read_value(client, LM75_REG_TEMP);
276 data->temp_max = lm75_read_value(client, LM75_REG_TEMP_OS);
277 data->temp_hyst = lm75_read_value(client, LM75_REG_TEMP_HYST);
278 data->last_updated = jiffies;
282 up(&data->update_lock);
285 static int __init sensors_lm75_init(void)
287 return i2c_add_driver(&lm75_driver);
290 static void __exit sensors_lm75_exit(void)
292 i2c_del_driver(&lm75_driver);
295 MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>");
296 MODULE_DESCRIPTION("LM75 driver");
297 MODULE_LICENSE("GPL");
299 module_init(sensors_lm75_init);
300 module_exit(sensors_lm75_exit);