drivers/hwmon/lm75.c

   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 #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/err.h>
  28 #include <linux/mutex.h>
  29 #include "lm75.h"
  30
  31
  32 /* Addresses to scan */
  33 static unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c,
  34                                         0x4d, 0x4e, 0x4f, I2C_CLIENT_END };
  35
  36 /* Insmod parameters */
  37 I2C_CLIENT_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 /* Each client has this additional data */
  48 struct lm75_data {
  49         struct i2c_client       client;
  50         struct class_device *class_dev;
  51         struct mutex            update_lock;
  52         char                    valid;          /* !=0 if following fields are valid */
  53         unsigned long           last_updated;   /* In jiffies */
  54         u16                     temp_input;     /* Register values */
  55         u16                     temp_max;
  56         u16                     temp_hyst;
  57 };
  58
  59 static int lm75_attach_adapter(struct i2c_adapter *adapter);
  60 static int lm75_detect(struct i2c_adapter *adapter, int address, int kind);
  61 static void lm75_init_client(struct i2c_client *client);
  62 static int lm75_detach_client(struct i2c_client *client);
  63 static int lm75_read_value(struct i2c_client *client, u8 reg);
  64 static int lm75_write_value(struct i2c_client *client, u8 reg, u16 value);
  65 static struct lm75_data *lm75_update_device(struct device *dev);
  66
  67
  68 /* This is the driver that will be inserted */
  69 static struct i2c_driver lm75_driver = {
  70         .driver = {
  71                 .name   = "lm75",
  72         },
  73         .id             = I2C_DRIVERID_LM75,
  74         .attach_adapter = lm75_attach_adapter,
  75         .detach_client  = lm75_detach_client,
  76 };
  77
  78 #define show(value)     \
  79 static ssize_t show_##value(struct device *dev, struct device_attribute *attr, char *buf)               \
  80 {                                                                       \
  81         struct lm75_data *data = lm75_update_device(dev);               \
  82         return sprintf(buf, "%d\n", LM75_TEMP_FROM_REG(data->value));   \
  83 }
  84 show(temp_max);
  85 show(temp_hyst);
  86 show(temp_input);
  87
  88 #define set(value, reg) \
  89 static ssize_t set_##value(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)    \
  90 {                                                               \
  91         struct i2c_client *client = to_i2c_client(dev);         \
  92         struct lm75_data *data = i2c_get_clientdata(client);    \
  93         int temp = simple_strtoul(buf, NULL, 10);               \
  94                                                                 \
  95         mutex_lock(&data->update_lock);                         \
  96         data->value = LM75_TEMP_TO_REG(temp);                   \
  97         lm75_write_value(client, reg, data->value);             \
  98         mutex_unlock(&data->update_lock);                                       \
  99         return count;                                           \
 100 }
 101 set(temp_max, LM75_REG_TEMP_OS);
 102 set(temp_hyst, LM75_REG_TEMP_HYST);
 103
 104 static DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp_max, set_temp_max);
 105 static DEVICE_ATTR(temp1_max_hyst, S_IWUSR | S_IRUGO, show_temp_hyst, set_temp_hyst);
 106 static DEVICE_ATTR(temp1_input, S_IRUGO, show_temp_input, NULL);
 107
 108 static int lm75_attach_adapter(struct i2c_adapter *adapter)
 109 {
 110         if (!(adapter->class & I2C_CLASS_HWMON))
 111                 return 0;
 112         return i2c_probe(adapter, &addr_data, lm75_detect);
 113 }
 114
 115 /* This function is called by i2c_probe */
 116 static int lm75_detect(struct i2c_adapter *adapter, int address, int kind)
 117 {
 118         int i;
 119         struct i2c_client *new_client;
 120         struct lm75_data *data;
 121         int err = 0;
 122         const char *name = "";
 123
 124         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
 125                                      I2C_FUNC_SMBUS_WORD_DATA))
 126                 goto exit;
 127
 128         /* OK. For now, we presume we have a valid client. We now create the
 129            client structure, even though we cannot fill it completely yet.
 130            But it allows us to access lm75_{read,write}_value. */
 131         if (!(data = kzalloc(sizeof(struct lm75_data), GFP_KERNEL))) {
 132                 err = -ENOMEM;
 133                 goto exit;
 134         }
 135
 136         new_client = &data->client;
 137         i2c_set_clientdata(new_client, data);
 138         new_client->addr = address;
 139         new_client->adapter = adapter;
 140         new_client->driver = &lm75_driver;
 141         new_client->flags = 0;
 142
 143         /* Now, we do the remaining detection. There is no identification-
 144            dedicated register so we have to rely on several tricks:
 145            unused bits, registers cycling over 8-address boundaries,
 146            addresses 0x04-0x07 returning the last read value.
 147            The cycling+unused addresses combination is not tested,
 148            since it would significantly slow the detection down and would
 149            hardly add any value. */
 150         if (kind < 0) {
 151                 int cur, conf, hyst, os;
 152
 153                 /* Unused addresses */
 154                 cur = i2c_smbus_read_word_data(new_client, 0);
 155                 conf = i2c_smbus_read_byte_data(new_client, 1);
 156                 hyst = i2c_smbus_read_word_data(new_client, 2);
 157                 if (i2c_smbus_read_word_data(new_client, 4) != hyst
 158                  || i2c_smbus_read_word_data(new_client, 5) != hyst
 159                  || i2c_smbus_read_word_data(new_client, 6) != hyst
 160                  || i2c_smbus_read_word_data(new_client, 7) != hyst)
 161                         goto exit_free;
 162                 os = i2c_smbus_read_word_data(new_client, 3);
 163                 if (i2c_smbus_read_word_data(new_client, 4) != os
 164                  || i2c_smbus_read_word_data(new_client, 5) != os
 165                  || i2c_smbus_read_word_data(new_client, 6) != os
 166                  || i2c_smbus_read_word_data(new_client, 7) != os)
 167                         goto exit_free;
 168
 169                 /* Unused bits */
 170                 if (conf & 0xe0)
 171                         goto exit_free;
 172
 173                 /* Addresses cycling */
 174                 for (i = 8; i < 0xff; i += 8)
 175                         if (i2c_smbus_read_byte_data(new_client, i + 1) != conf
 176                          || i2c_smbus_read_word_data(new_client, i + 2) != hyst
 177                          || i2c_smbus_read_word_data(new_client, i + 3) != os)
 178                                 goto exit_free;
 179         }
 180
 181         /* Determine the chip type - only one kind supported! */
 182         if (kind <= 0)
 183                 kind = lm75;
 184
 185         if (kind == lm75) {
 186                 name = "lm75";
 187         }
 188
 189         /* Fill in the remaining client fields and put it into the global list */
 190         strlcpy(new_client->name, name, I2C_NAME_SIZE);
 191         data->valid = 0;
 192         mutex_init(&data->update_lock);
 193
 194         /* Tell the I2C layer a new client has arrived */
 195         if ((err = i2c_attach_client(new_client)))
 196                 goto exit_free;
 197
 198         /* Initialize the LM75 chip */
 199         lm75_init_client(new_client);
 200
 201         /* Register sysfs hooks */
 202         data->class_dev = hwmon_device_register(&new_client->dev);
 203         if (IS_ERR(data->class_dev)) {
 204                 err = PTR_ERR(data->class_dev);
 205                 goto exit_detach;
 206         }
 207
 208         device_create_file(&new_client->dev, &dev_attr_temp1_max);
 209         device_create_file(&new_client->dev, &dev_attr_temp1_max_hyst);
 210         device_create_file(&new_client->dev, &dev_attr_temp1_input);
 211
 212         return 0;
 213
 214 exit_detach:
 215         i2c_detach_client(new_client);
 216 exit_free:
 217         kfree(data);
 218 exit:
 219         return err;
 220 }
 221
 222 static int lm75_detach_client(struct i2c_client *client)
 223 {
 224         struct lm75_data *data = i2c_get_clientdata(client);
 225         hwmon_device_unregister(data->class_dev);
 226         i2c_detach_client(client);
 227         kfree(data);
 228         return 0;
 229 }
 230
 231 /* All registers are word-sized, except for the configuration register.
 232    LM75 uses a high-byte first convention, which is exactly opposite to
 233    the usual practice. */
 234 static int lm75_read_value(struct i2c_client *client, u8 reg)
 235 {
 236         if (reg == LM75_REG_CONF)
 237                 return i2c_smbus_read_byte_data(client, reg);
 238         else
 239                 return swab16(i2c_smbus_read_word_data(client, reg));
 240 }
 241
 242 /* All registers are word-sized, except for the configuration register.
 243    LM75 uses a high-byte first convention, which is exactly opposite to
 244    the usual practice. */
 245 static int lm75_write_value(struct i2c_client *client, u8 reg, u16 value)
 246 {
 247         if (reg == LM75_REG_CONF)
 248                 return i2c_smbus_write_byte_data(client, reg, value);
 249         else
 250                 return i2c_smbus_write_word_data(client, reg, swab16(value));
 251 }
 252
 253 static void lm75_init_client(struct i2c_client *client)
 254 {
 255         int reg;
 256
 257         /* Enable if in shutdown mode */
 258         reg = lm75_read_value(client, LM75_REG_CONF);
 259         if (reg >= 0 && (reg & 0x01))
 260                 lm75_write_value(client, LM75_REG_CONF, reg & 0xfe);
 261 }
 262
 263 static struct lm75_data *lm75_update_device(struct device *dev)
 264 {
 265         struct i2c_client *client = to_i2c_client(dev);
 266         struct lm75_data *data = i2c_get_clientdata(client);
 267
 268         mutex_lock(&data->update_lock);
 269
 270         if (time_after(jiffies, data->last_updated + HZ + HZ / 2)
 271             || !data->valid) {
 272                 dev_dbg(&client->dev, "Starting lm75 update\n");
 273
 274                 data->temp_input = lm75_read_value(client, LM75_REG_TEMP);
 275                 data->temp_max = lm75_read_value(client, LM75_REG_TEMP_OS);
 276                 data->temp_hyst = lm75_read_value(client, LM75_REG_TEMP_HYST);
 277                 data->last_updated = jiffies;
 278                 data->valid = 1;
 279         }
 280
 281         mutex_unlock(&data->update_lock);
 282
 283         return data;
 284 }
 285
 286 static int __init sensors_lm75_init(void)
 287 {
 288         return i2c_add_driver(&lm75_driver);
 289 }
 290
 291 static void __exit sensors_lm75_exit(void)
 292 {
 293         i2c_del_driver(&lm75_driver);
 294 }
 295
 296 MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>");
 297 MODULE_DESCRIPTION("LM75 driver");
 298 MODULE_LICENSE("GPL");
 299
 300 module_init(sensors_lm75_init);
 301 module_exit(sensors_lm75_exit);