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420 giacomo 1
/*
2
    lm75.c - Part of lm_sensors, Linux kernel modules for hardware
3
             monitoring
4
    Copyright (c) 1998, 1999  Frodo Looijaard <frodol@dds.nl>
5
 
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.
10
 
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.
15
 
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.
19
*/
20
 
21
/* #define DEBUG 1 */
22
 
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>
28
 
29
 
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 };
35
 
36
/* Insmod parameters */
37
SENSORS_INSMOD_1(lm75);
38
 
39
/* Many LM75 constants specified below */
40
 
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
46
 
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))
53
 
54
/* Initial values */
55
#define LM75_INIT_TEMP_OS       600
56
#define LM75_INIT_TEMP_HYST     500
57
 
58
/* Each client has this additional data */
59
struct lm75_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 */
64
        u16                     temp_max;
65
        u16                     temp_hyst;
66
};
67
 
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);
75
 
76
 
77
/* This is the driver that will be inserted */
78
static struct i2c_driver lm75_driver = {
79
        .owner          = THIS_MODULE,
80
        .name           = "lm75",
81
        .id             = I2C_DRIVERID_LM75,
82
        .flags          = I2C_DF_NOTIFY,
83
        .attach_adapter = lm75_attach_adapter,
84
        .detach_client  = lm75_detach_client,
85
};
86
 
87
static int lm75_id = 0;
88
 
89
#define show(value)     \
90
static ssize_t show_##value(struct device *dev, char *buf)      \
91
{                                                               \
92
        struct i2c_client *client = to_i2c_client(dev);         \
93
        struct lm75_data *data = i2c_get_clientdata(client);    \
94
        int temp;                                               \
95
                                                                \
96
        lm75_update_client(client);                             \
97
        temp = TEMP_FROM_REG(data->value);                      \
98
        return sprintf(buf, "%d\n", temp * 100);                \
99
}
100
show(temp_max);
101
show(temp_hyst);
102
show(temp_input);
103
 
104
#define set(value, reg) \
105
static ssize_t set_##value(struct device *dev, const char *buf, size_t count)   \
106
{                                                               \
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;         \
110
                                                                \
111
        data->value = TEMP_TO_REG(temp);                        \
112
        lm75_write_value(client, reg, data->value);             \
113
        return count;                                           \
114
}
115
set(temp_max, LM75_REG_TEMP_OS);
116
set(temp_hyst, LM75_REG_TEMP_HYST);
117
 
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);
121
 
122
static int lm75_attach_adapter(struct i2c_adapter *adapter)
123
{
124
        if (!(adapter->class & I2C_ADAP_CLASS_SMBUS))
125
                return 0;
126
        return i2c_detect(adapter, &addr_data, lm75_detect);
127
}
128
 
129
/* This function is called by i2c_detect */
130
static int lm75_detect(struct i2c_adapter *adapter, int address, int kind)
131
{
132
        int i, cur, conf, hyst, os;
133
        struct i2c_client *new_client;
134
        struct lm75_data *data;
135
        int err = 0;
136
        const char *name;
137
 
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. */
140
#ifdef DEBUG
141
        if (i2c_is_isa_adapter(adapter)) {
142
                dev_dbg(&adapter->dev,
143
                        "lm75_detect called for an ISA bus adapter?!?\n");
144
                goto exit;
145
        }
146
#endif
147
 
148
        if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
149
                                     I2C_FUNC_SMBUS_WORD_DATA))
150
                goto exit;
151
 
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),
157
                                   GFP_KERNEL))) {
158
                err = -ENOMEM;
159
                goto exit;
160
        }
161
        memset(new_client, 0x00, sizeof(struct i2c_client) +
162
                                 sizeof(struct lm75_data));
163
 
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;
170
 
171
        /* Now, we do the remaining detection. It is lousy. */
172
        if (kind < 0) {
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))
181
                                goto exit_free;
182
        }
183
 
184
        /* Determine the chip type - only one kind supported! */
185
        if (kind <= 0)
186
                kind = lm75;
187
 
188
        if (kind == lm75) {
189
                name = "lm75";
190
        } else {
191
                dev_dbg(&adapter->dev, "Internal error: unknown kind (%d)?!?",
192
                        kind);
193
                goto exit_free;
194
        }
195
 
196
        /* Fill in the remaining client fields and put it into the global list */
197
        strlcpy(new_client->name, name, I2C_NAME_SIZE);
198
 
199
        new_client->id = lm75_id++;
200
        data->valid = 0;
201
        init_MUTEX(&data->update_lock);
202
 
203
        /* Tell the I2C layer a new client has arrived */
204
        if ((err = i2c_attach_client(new_client)))
205
                goto exit_free;
206
 
207
        /* Initialize the LM75 chip */
208
        lm75_init_client(new_client);
209
 
210
        /* Register sysfs hooks */
211
        device_create_file(&new_client->dev, &dev_attr_temp_max);
212
        device_create_file(&new_client->dev, &dev_attr_temp_min);
213
        device_create_file(&new_client->dev, &dev_attr_temp_input);
214
 
215
        return 0;
216
 
217
exit_free:
218
        kfree(new_client);
219
exit:
220
        return err;
221
}
222
 
223
static int lm75_detach_client(struct i2c_client *client)
224
{
225
        i2c_detach_client(client);
226
        kfree(client);
227
        return 0;
228
}
229
 
230
static u16 swap_bytes(u16 val)
231
{
232
        return (val >> 8) | (val << 8);
233
}
234
 
235
/* All registers are word-sized, except for the configuration register.
236
   LM75 uses a high-byte first convention, which is exactly opposite to
237
   the usual practice. */
238
static int lm75_read_value(struct i2c_client *client, u8 reg)
239
{
240
        if (reg == LM75_REG_CONF)
241
                return i2c_smbus_read_byte_data(client, reg);
242
        else
243
                return swap_bytes(i2c_smbus_read_word_data(client, reg));
244
}
245
 
246
/* All registers are word-sized, except for the configuration register.
247
   LM75 uses a high-byte first convention, which is exactly opposite to
248
   the usual practice. */
249
static int lm75_write_value(struct i2c_client *client, u8 reg, u16 value)
250
{
251
        if (reg == LM75_REG_CONF)
252
                return i2c_smbus_write_byte_data(client, reg, value);
253
        else
254
                return i2c_smbus_write_word_data(client, reg,
255
                                                 swap_bytes(value));
256
}
257
 
258
static void lm75_init_client(struct i2c_client *client)
259
{
260
        /* Initialize the LM75 chip */
261
        lm75_write_value(client, LM75_REG_TEMP_OS,
262
                         TEMP_TO_REG(LM75_INIT_TEMP_OS));
263
        lm75_write_value(client, LM75_REG_TEMP_HYST,
264
                         TEMP_TO_REG(LM75_INIT_TEMP_HYST));
265
        lm75_write_value(client, LM75_REG_CONF, 0);
266
}
267
 
268
static void lm75_update_client(struct i2c_client *client)
269
{
270
        struct lm75_data *data = i2c_get_clientdata(client);
271
 
272
        down(&data->update_lock);
273
 
274
        if ((jiffies - data->last_updated > HZ + HZ / 2) ||
275
            (jiffies < data->last_updated) || !data->valid) {
276
                dev_dbg(&client->dev, "Starting lm75 update\n");
277
 
278
                data->temp_input = lm75_read_value(client, LM75_REG_TEMP);
279
                data->temp_max = lm75_read_value(client, LM75_REG_TEMP_OS);
280
                data->temp_hyst = lm75_read_value(client, LM75_REG_TEMP_HYST);
281
                data->last_updated = jiffies;
282
                data->valid = 1;
283
        }
284
 
285
        up(&data->update_lock);
286
}
287
 
288
static int __init sensors_lm75_init(void)
289
{
290
        return i2c_add_driver(&lm75_driver);
291
}
292
 
293
static void __exit sensors_lm75_exit(void)
294
{
295
        i2c_del_driver(&lm75_driver);
296
}
297
 
298
MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>");
299
MODULE_DESCRIPTION("LM75 driver");
300
MODULE_LICENSE("GPL");
301
 
302
module_init(sensors_lm75_init);
303
module_exit(sensors_lm75_exit);