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/hwmon-sysfs.h>
  28 #include <linux/err.h>
  29 #include <linux/mutex.h>
  30 #include "lm75.h"
  31
  32
  33 /* Addresses to scan */
  34 <<<<<<< HEAD:drivers/hwmon/lm75.c
  35 static unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c,
  36 =======
  37 static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c,
  38 >>>>>>> 264e3e889d86e552b4191d69bb60f4f3b383135a:drivers/hwmon/lm75.c
  39                                         0x4d, 0x4e, 0x4f, I2C_CLIENT_END };
  40
  41 /* Insmod parameters */
  42 I2C_CLIENT_INSMOD_1(lm75);
  43
  44 /* Many LM75 constants specified below */
  45
  46 /* The LM75 registers */
  47 #define LM75_REG_CONF           0x01
  48 static const u8 LM75_REG_TEMP[3] = {
  49         0x00,           /* input */
  50         0x03,           /* max */
  51         0x02,           /* hyst */
  52 };
  53
  54 /* Each client has this additional data */
  55 struct lm75_data {
  56         struct i2c_client       client;
  57         struct device *hwmon_dev;
  58         struct mutex            update_lock;
  59         char                    valid;          /* !=0 if following fields are valid */
  60         unsigned long           last_updated;   /* In jiffies */
  61         u16                     temp[3];        /* Register values,
  62                                                    0 = input
  63                                                    1 = max
  64                                                    2 = hyst */
  65 };
  66
  67 static int lm75_attach_adapter(struct i2c_adapter *adapter);
  68 static int lm75_detect(struct i2c_adapter *adapter, int address, int kind);
  69 static void lm75_init_client(struct i2c_client *client);
  70 static int lm75_detach_client(struct i2c_client *client);
  71 static int lm75_read_value(struct i2c_client *client, u8 reg);
  72 static int lm75_write_value(struct i2c_client *client, u8 reg, u16 value);
  73 static struct lm75_data *lm75_update_device(struct device *dev);
  74
  75
  76 /* This is the driver that will be inserted */
  77 static struct i2c_driver lm75_driver = {
  78         .driver = {
  79                 .name   = "lm75",
  80         },
  81         .attach_adapter = lm75_attach_adapter,
  82         .detach_client  = lm75_detach_client,
  83 };
  84
  85 static ssize_t show_temp(struct device *dev, struct device_attribute *da,
  86                          char *buf)
  87 {
  88         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
  89         struct lm75_data *data = lm75_update_device(dev);
  90         return sprintf(buf, "%d\n",
  91                        LM75_TEMP_FROM_REG(data->temp[attr->index]));
  92 }
  93
  94 static ssize_t set_temp(struct device *dev, struct device_attribute *da,
  95                         const char *buf, size_t count)
  96 {
  97         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
  98         struct i2c_client *client = to_i2c_client(dev);
  99         struct lm75_data *data = i2c_get_clientdata(client);
 100         int nr = attr->index;
 101         long temp = simple_strtol(buf, NULL, 10);
 102
 103         mutex_lock(&data->update_lock);
 104         data->temp[nr] = LM75_TEMP_TO_REG(temp);
 105         lm75_write_value(client, LM75_REG_TEMP[nr], data->temp[nr]);
 106         mutex_unlock(&data->update_lock);
 107         return count;
 108 }
 109
 110 static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO,
 111                         show_temp, set_temp, 1);
 112 static SENSOR_DEVICE_ATTR(temp1_max_hyst, S_IWUSR | S_IRUGO,
 113                         show_temp, set_temp, 2);
 114 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0);
 115
 116 static int lm75_attach_adapter(struct i2c_adapter *adapter)
 117 {
 118         if (!(adapter->class & I2C_CLASS_HWMON))
 119                 return 0;
 120         return i2c_probe(adapter, &addr_data, lm75_detect);
 121 }
 122
 123 static struct attribute *lm75_attributes[] = {
 124         &sensor_dev_attr_temp1_input.dev_attr.attr,
 125         &sensor_dev_attr_temp1_max.dev_attr.attr,
 126         &sensor_dev_attr_temp1_max_hyst.dev_attr.attr,
 127
 128         NULL
 129 };
 130
 131 static const struct attribute_group lm75_group = {
 132         .attrs = lm75_attributes,
 133 };
 134
 135 /* This function is called by i2c_probe */
 136 static int lm75_detect(struct i2c_adapter *adapter, int address, int kind)
 137 {
 138         int i;
 139         struct i2c_client *new_client;
 140         struct lm75_data *data;
 141         int err = 0;
 142         const char *name = "";
 143
 144         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
 145                                      I2C_FUNC_SMBUS_WORD_DATA))
 146                 goto exit;
 147
 148         /* OK. For now, we presume we have a valid client. We now create the
 149            client structure, even though we cannot fill it completely yet.
 150            But it allows us to access lm75_{read,write}_value. */
 151         if (!(data = kzalloc(sizeof(struct lm75_data), GFP_KERNEL))) {
 152                 err = -ENOMEM;
 153                 goto exit;
 154         }
 155
 156         new_client = &data->client;
 157         i2c_set_clientdata(new_client, data);
 158         new_client->addr = address;
 159         new_client->adapter = adapter;
 160         new_client->driver = &lm75_driver;
 161         new_client->flags = 0;
 162
 163         /* Now, we do the remaining detection. There is no identification-
 164            dedicated register so we have to rely on several tricks:
 165            unused bits, registers cycling over 8-address boundaries,
 166            addresses 0x04-0x07 returning the last read value.
 167            The cycling+unused addresses combination is not tested,
 168            since it would significantly slow the detection down and would
 169            hardly add any value. */
 170         if (kind < 0) {
 171                 int cur, conf, hyst, os;
 172
 173                 /* Unused addresses */
 174                 cur = i2c_smbus_read_word_data(new_client, 0);
 175                 conf = i2c_smbus_read_byte_data(new_client, 1);
 176                 hyst = i2c_smbus_read_word_data(new_client, 2);
 177                 if (i2c_smbus_read_word_data(new_client, 4) != hyst
 178                  || i2c_smbus_read_word_data(new_client, 5) != hyst
 179                  || i2c_smbus_read_word_data(new_client, 6) != hyst
 180                  || i2c_smbus_read_word_data(new_client, 7) != hyst)
 181                         goto exit_free;
 182                 os = i2c_smbus_read_word_data(new_client, 3);
 183                 if (i2c_smbus_read_word_data(new_client, 4) != os
 184                  || i2c_smbus_read_word_data(new_client, 5) != os
 185                  || i2c_smbus_read_word_data(new_client, 6) != os
 186                  || i2c_smbus_read_word_data(new_client, 7) != os)
 187                         goto exit_free;
 188
 189                 /* Unused bits */
 190                 if (conf & 0xe0)
 191                         goto exit_free;
 192
 193                 /* Addresses cycling */
 194                 for (i = 8; i < 0xff; i += 8)
 195                         if (i2c_smbus_read_byte_data(new_client, i + 1) != conf
 196                          || i2c_smbus_read_word_data(new_client, i + 2) != hyst
 197                          || i2c_smbus_read_word_data(new_client, i + 3) != os)
 198                                 goto exit_free;
 199         }
 200
 201         /* Determine the chip type - only one kind supported! */
 202         if (kind <= 0)
 203                 kind = lm75;
 204
 205         if (kind == lm75) {
 206                 name = "lm75";
 207         }
 208
 209         /* Fill in the remaining client fields and put it into the global list */
 210         strlcpy(new_client->name, name, I2C_NAME_SIZE);
 211         data->valid = 0;
 212         mutex_init(&data->update_lock);
 213
 214         /* Tell the I2C layer a new client has arrived */
 215         if ((err = i2c_attach_client(new_client)))
 216                 goto exit_free;
 217
 218         /* Initialize the LM75 chip */
 219         lm75_init_client(new_client);
 220
 221         /* Register sysfs hooks */
 222         if ((err = sysfs_create_group(&new_client->dev.kobj, &lm75_group)))
 223                 goto exit_detach;
 224
 225         data->hwmon_dev = hwmon_device_register(&new_client->dev);
 226         if (IS_ERR(data->hwmon_dev)) {
 227                 err = PTR_ERR(data->hwmon_dev);
 228                 goto exit_remove;
 229         }
 230
 231         return 0;
 232
 233 exit_remove:
 234         sysfs_remove_group(&new_client->dev.kobj, &lm75_group);
 235 exit_detach:
 236         i2c_detach_client(new_client);
 237 exit_free:
 238         kfree(data);
 239 exit:
 240         return err;
 241 }
 242
 243 static int lm75_detach_client(struct i2c_client *client)
 244 {
 245         struct lm75_data *data = i2c_get_clientdata(client);
 246         hwmon_device_unregister(data->hwmon_dev);
 247         sysfs_remove_group(&client->dev.kobj, &lm75_group);
 248         i2c_detach_client(client);
 249         kfree(data);
 250         return 0;
 251 }
 252
 253 /* All registers are word-sized, except for the configuration register.
 254    LM75 uses a high-byte first convention, which is exactly opposite to
 255    the usual practice. */
 256 static int lm75_read_value(struct i2c_client *client, u8 reg)
 257 {
 258         if (reg == LM75_REG_CONF)
 259                 return i2c_smbus_read_byte_data(client, reg);
 260         else
 261                 return swab16(i2c_smbus_read_word_data(client, reg));
 262 }
 263
 264 /* All registers are word-sized, except for the configuration register.
 265    LM75 uses a high-byte first convention, which is exactly opposite to
 266    the usual practice. */
 267 static int lm75_write_value(struct i2c_client *client, u8 reg, u16 value)
 268 {
 269         if (reg == LM75_REG_CONF)
 270                 return i2c_smbus_write_byte_data(client, reg, value);
 271         else
 272                 return i2c_smbus_write_word_data(client, reg, swab16(value));
 273 }
 274
 275 static void lm75_init_client(struct i2c_client *client)
 276 {
 277         int reg;
 278
 279         /* Enable if in shutdown mode */
 280         reg = lm75_read_value(client, LM75_REG_CONF);
 281         if (reg >= 0 && (reg & 0x01))
 282                 lm75_write_value(client, LM75_REG_CONF, reg & 0xfe);
 283 }
 284
 285 static struct lm75_data *lm75_update_device(struct device *dev)
 286 {
 287         struct i2c_client *client = to_i2c_client(dev);
 288         struct lm75_data *data = i2c_get_clientdata(client);
 289
 290         mutex_lock(&data->update_lock);
 291
 292         if (time_after(jiffies, data->last_updated + HZ + HZ / 2)
 293             || !data->valid) {
 294                 int i;
 295                 dev_dbg(&client->dev, "Starting lm75 update\n");
 296
 297                 for (i = 0; i < ARRAY_SIZE(data->temp); i++)
 298                         data->temp[i] = lm75_read_value(client,
 299                                                         LM75_REG_TEMP[i]);
 300                 data->last_updated = jiffies;
 301                 data->valid = 1;
 302         }
 303
 304         mutex_unlock(&data->update_lock);
 305
 306         return data;
 307 }
 308
 309 static int __init sensors_lm75_init(void)
 310 {
 311         return i2c_add_driver(&lm75_driver);
 312 }
 313
 314 static void __exit sensors_lm75_exit(void)
 315 {
 316         i2c_del_driver(&lm75_driver);
 317 }
 318
 319 MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>");
 320 MODULE_DESCRIPTION("LM75 driver");
 321 MODULE_LICENSE("GPL");
 322
 323 module_init(sensors_lm75_init);
 324 module_exit(sensors_lm75_exit);