drivers/hwmon/ds1621.c

   1 /*
   2     ds1621.c - Part of lm_sensors, Linux kernel modules for hardware
   3              monitoring
   4     Christian W. Zuckschwerdt  <zany@triq.net>  2000-11-23
   5     based on lm75.c by Frodo Looijaard <frodol@dds.nl>
   6     Ported to Linux 2.6 by Aurelien Jarno <aurelien@aurel32.net> with
   7     the help of Jean Delvare <khali@linux-fr.org>
   8
   9     This program is free software; you can redistribute it and/or modify
  10     it under the terms of the GNU General Public License as published by
  11     the Free Software Foundation; either version 2 of the License, or
  12     (at your option) any later version.
  13
  14     This program is distributed in the hope that it will be useful,
  15     but WITHOUT ANY WARRANTY; without even the implied warranty of
  16     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17     GNU General Public License for more details.
  18
  19     You should have received a copy of the GNU General Public License
  20     along with this program; if not, write to the Free Software
  21     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  22 */
  23
  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/err.h>
  31 #include <linux/mutex.h>
  32 #include <linux/sysfs.h>
  33 #include "lm75.h"
  34
  35 /* Addresses to scan */
  36 static unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c,
  37                                         0x4d, 0x4e, 0x4f, I2C_CLIENT_END };
  38
  39 /* Insmod parameters */
  40 I2C_CLIENT_INSMOD_1(ds1621);
  41 static int polarity = -1;
  42 module_param(polarity, int, 0);
  43 MODULE_PARM_DESC(polarity, "Output's polarity: 0 = active high, 1 = active low");
  44
  45 /* Many DS1621 constants specified below */
  46 /* Config register used for detection         */
  47 /*  7    6    5    4    3    2    1    0      */
  48 /* |Done|THF |TLF |NVB | X  | X  |POL |1SHOT| */
  49 #define DS1621_REG_CONFIG_NVB           0x10
  50 #define DS1621_REG_CONFIG_POLARITY      0x02
  51 #define DS1621_REG_CONFIG_1SHOT         0x01
  52 #define DS1621_REG_CONFIG_DONE          0x80
  53
  54 /* The DS1621 registers */
  55 #define DS1621_REG_TEMP                 0xAA /* word, RO */
  56 #define DS1621_REG_TEMP_MIN             0xA1 /* word, RW */
  57 #define DS1621_REG_TEMP_MAX             0xA2 /* word, RW */
  58 #define DS1621_REG_CONF                 0xAC /* byte, RW */
  59 #define DS1621_COM_START                0xEE /* no data */
  60 #define DS1621_COM_STOP                 0x22 /* no data */
  61
  62 /* The DS1621 configuration register */
  63 #define DS1621_ALARM_TEMP_HIGH          0x40
  64 #define DS1621_ALARM_TEMP_LOW           0x20
  65
  66 /* Conversions. Rounding and limit checking is only done on the TO_REG
  67    variants. Note that you should be a bit careful with which arguments
  68    these macros are called: arguments may be evaluated more than once.
  69    Fixing this is just not worth it. */
  70 #define ALARMS_FROM_REG(val) ((val) & \
  71                               (DS1621_ALARM_TEMP_HIGH | DS1621_ALARM_TEMP_LOW))
  72
  73 /* Each client has this additional data */
  74 struct ds1621_data {
  75         struct i2c_client client;
  76         struct class_device *class_dev;
  77         struct mutex update_lock;
  78         char valid;                     /* !=0 if following fields are valid */
  79         unsigned long last_updated;     /* In jiffies */
  80
  81         u16 temp, temp_min, temp_max;   /* Register values, word */
  82         u8 conf;                        /* Register encoding, combined */
  83 };
  84
  85 static int ds1621_attach_adapter(struct i2c_adapter *adapter);
  86 static int ds1621_detect(struct i2c_adapter *adapter, int address,
  87                          int kind);
  88 static void ds1621_init_client(struct i2c_client *client);
  89 static int ds1621_detach_client(struct i2c_client *client);
  90 static struct ds1621_data *ds1621_update_client(struct device *dev);
  91
  92 /* This is the driver that will be inserted */
  93 static struct i2c_driver ds1621_driver = {
  94         .driver = {
  95                 .name   = "ds1621",
  96         },
  97         .id             = I2C_DRIVERID_DS1621,
  98         .attach_adapter = ds1621_attach_adapter,
  99         .detach_client  = ds1621_detach_client,
 100 };
 101
 102 /* All registers are word-sized, except for the configuration register.
 103    DS1621 uses a high-byte first convention, which is exactly opposite to
 104    the usual practice. */
 105 static int ds1621_read_value(struct i2c_client *client, u8 reg)
 106 {
 107         if (reg == DS1621_REG_CONF)
 108                 return i2c_smbus_read_byte_data(client, reg);
 109         else
 110                 return swab16(i2c_smbus_read_word_data(client, reg));
 111 }
 112
 113 /* All registers are word-sized, except for the configuration register.
 114    DS1621 uses a high-byte first convention, which is exactly opposite to
 115    the usual practice. */
 116 static int ds1621_write_value(struct i2c_client *client, u8 reg, u16 value)
 117 {
 118         if (reg == DS1621_REG_CONF)
 119                 return i2c_smbus_write_byte_data(client, reg, value);
 120         else
 121                 return i2c_smbus_write_word_data(client, reg, swab16(value));
 122 }
 123
 124 static void ds1621_init_client(struct i2c_client *client)
 125 {
 126         int reg = ds1621_read_value(client, DS1621_REG_CONF);
 127         /* switch to continuous conversion mode */
 128         reg &= ~ DS1621_REG_CONFIG_1SHOT;
 129
 130         /* setup output polarity */
 131         if (polarity == 0)
 132                 reg &= ~DS1621_REG_CONFIG_POLARITY;
 133         else if (polarity == 1)
 134                 reg |= DS1621_REG_CONFIG_POLARITY;
 135
 136         ds1621_write_value(client, DS1621_REG_CONF, reg);
 137
 138         /* start conversion */
 139         i2c_smbus_write_byte(client, DS1621_COM_START);
 140 }
 141
 142 #define show(value)                                                     \
 143 static ssize_t show_##value(struct device *dev, struct device_attribute *attr, char *buf)               \
 144 {                                                                       \
 145         struct ds1621_data *data = ds1621_update_client(dev);           \
 146         return sprintf(buf, "%d\n", LM75_TEMP_FROM_REG(data->value));   \
 147 }
 148
 149 show(temp);
 150 show(temp_min);
 151 show(temp_max);
 152
 153 #define set_temp(suffix, value, reg)                                    \
 154 static ssize_t set_temp_##suffix(struct device *dev, struct device_attribute *attr, const char *buf,    \
 155                                  size_t count)                          \
 156 {                                                                       \
 157         struct i2c_client *client = to_i2c_client(dev);                 \
 158         struct ds1621_data *data = ds1621_update_client(dev);           \
 159         u16 val = LM75_TEMP_TO_REG(simple_strtoul(buf, NULL, 10));      \
 160                                                                         \
 161         mutex_lock(&data->update_lock);                                 \
 162         data->value = val;                                              \
 163         ds1621_write_value(client, reg, data->value);                   \
 164         mutex_unlock(&data->update_lock);                               \
 165         return count;                                                   \
 166 }
 167
 168 set_temp(min, temp_min, DS1621_REG_TEMP_MIN);
 169 set_temp(max, temp_max, DS1621_REG_TEMP_MAX);
 170
 171 static ssize_t show_alarms(struct device *dev, struct device_attribute *attr, char *buf)
 172 {
 173         struct ds1621_data *data = ds1621_update_client(dev);
 174         return sprintf(buf, "%d\n", ALARMS_FROM_REG(data->conf));
 175 }
 176
 177 static DEVICE_ATTR(alarms, S_IRUGO, show_alarms, NULL);
 178 static DEVICE_ATTR(temp1_input, S_IRUGO , show_temp, NULL);
 179 static DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO , show_temp_min, set_temp_min);
 180 static DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp_max, set_temp_max);
 181
 182 static struct attribute *ds1621_attributes[] = {
 183         &dev_attr_temp1_input.attr,
 184         &dev_attr_temp1_min.attr,
 185         &dev_attr_temp1_max.attr,
 186         &dev_attr_alarms.attr,
 187         NULL
 188 };
 189
 190 static const struct attribute_group ds1621_group = {
 191         .attrs = ds1621_attributes,
 192 };
 193
 194
 195 static int ds1621_attach_adapter(struct i2c_adapter *adapter)
 196 {
 197         if (!(adapter->class & I2C_CLASS_HWMON))
 198                 return 0;
 199         return i2c_probe(adapter, &addr_data, ds1621_detect);
 200 }
 201
 202 /* This function is called by i2c_probe */
 203 static int ds1621_detect(struct i2c_adapter *adapter, int address,
 204                          int kind)
 205 {
 206         int conf, temp;
 207         struct i2c_client *new_client;
 208         struct ds1621_data *data;
 209         int err = 0;
 210
 211         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA
 212                                      | I2C_FUNC_SMBUS_WORD_DATA
 213                                      | I2C_FUNC_SMBUS_WRITE_BYTE))
 214                 goto exit;
 215
 216         /* OK. For now, we presume we have a valid client. We now create the
 217            client structure, even though we cannot fill it completely yet.
 218            But it allows us to access ds1621_{read,write}_value. */
 219         if (!(data = kzalloc(sizeof(struct ds1621_data), GFP_KERNEL))) {
 220                 err = -ENOMEM;
 221                 goto exit;
 222         }
 223
 224         new_client = &data->client;
 225         i2c_set_clientdata(new_client, data);
 226         new_client->addr = address;
 227         new_client->adapter = adapter;
 228         new_client->driver = &ds1621_driver;
 229         new_client->flags = 0;
 230
 231
 232         /* Now, we do the remaining detection. It is lousy. */
 233         if (kind < 0) {
 234                 /* The NVB bit should be low if no EEPROM write has been
 235                    requested during the latest 10ms, which is highly
 236                    improbable in our case. */
 237                 conf = ds1621_read_value(new_client, DS1621_REG_CONF);
 238                 if (conf & DS1621_REG_CONFIG_NVB)
 239                         goto exit_free;
 240                 /* The 7 lowest bits of a temperature should always be 0. */
 241                 temp = ds1621_read_value(new_client, DS1621_REG_TEMP);
 242                 if (temp & 0x007f)
 243                         goto exit_free;
 244                 temp = ds1621_read_value(new_client, DS1621_REG_TEMP_MIN);
 245                 if (temp & 0x007f)
 246                         goto exit_free;
 247                 temp = ds1621_read_value(new_client, DS1621_REG_TEMP_MAX);
 248                 if (temp & 0x007f)
 249                         goto exit_free;
 250         }
 251
 252         /* Determine the chip type - only one kind supported! */
 253         if (kind <= 0)
 254                 kind = ds1621;
 255
 256         /* Fill in remaining client fields and put it into the global list */
 257         strlcpy(new_client->name, "ds1621", I2C_NAME_SIZE);
 258         data->valid = 0;
 259         mutex_init(&data->update_lock);
 260
 261         /* Tell the I2C layer a new client has arrived */
 262         if ((err = i2c_attach_client(new_client)))
 263                 goto exit_free;
 264
 265         /* Initialize the DS1621 chip */
 266         ds1621_init_client(new_client);
 267
 268         /* Register sysfs hooks */
 269         if ((err = sysfs_create_group(&new_client->dev.kobj, &ds1621_group)))
 270                 goto exit_detach;
 271
 272         data->class_dev = hwmon_device_register(&new_client->dev);
 273         if (IS_ERR(data->class_dev)) {
 274                 err = PTR_ERR(data->class_dev);
 275                 goto exit_remove_files;
 276         }
 277
 278         return 0;
 279
 280       exit_remove_files:
 281         sysfs_remove_group(&new_client->dev.kobj, &ds1621_group);
 282       exit_detach:
 283         i2c_detach_client(new_client);
 284       exit_free:
 285         kfree(data);
 286       exit:
 287         return err;
 288 }
 289
 290 static int ds1621_detach_client(struct i2c_client *client)
 291 {
 292         struct ds1621_data *data = i2c_get_clientdata(client);
 293         int err;
 294
 295         hwmon_device_unregister(data->class_dev);
 296         sysfs_remove_group(&client->dev.kobj, &ds1621_group);
 297
 298         if ((err = i2c_detach_client(client)))
 299                 return err;
 300
 301         kfree(data);
 302
 303         return 0;
 304 }
 305
 306
 307 static struct ds1621_data *ds1621_update_client(struct device *dev)
 308 {
 309         struct i2c_client *client = to_i2c_client(dev);
 310         struct ds1621_data *data = i2c_get_clientdata(client);
 311         u8 new_conf;
 312
 313         mutex_lock(&data->update_lock);
 314
 315         if (time_after(jiffies, data->last_updated + HZ + HZ / 2)
 316             || !data->valid) {
 317
 318                 dev_dbg(&client->dev, "Starting ds1621 update\n");
 319
 320                 data->conf = ds1621_read_value(client, DS1621_REG_CONF);
 321
 322                 data->temp = ds1621_read_value(client, DS1621_REG_TEMP);
 323
 324                 data->temp_min = ds1621_read_value(client,
 325                                                     DS1621_REG_TEMP_MIN);
 326                 data->temp_max = ds1621_read_value(client,
 327                                                     DS1621_REG_TEMP_MAX);
 328
 329                 /* reset alarms if necessary */
 330                 new_conf = data->conf;
 331                 if (data->temp < data->temp_min)
 332                         new_conf &= ~DS1621_ALARM_TEMP_LOW;
 333                 if (data->temp > data->temp_max)
 334                         new_conf &= ~DS1621_ALARM_TEMP_HIGH;
 335                 if (data->conf != new_conf)
 336                         ds1621_write_value(client, DS1621_REG_CONF,
 337                                            new_conf);
 338
 339                 data->last_updated = jiffies;
 340                 data->valid = 1;
 341         }
 342
 343         mutex_unlock(&data->update_lock);
 344
 345         return data;
 346 }
 347
 348 static int __init ds1621_init(void)
 349 {
 350         return i2c_add_driver(&ds1621_driver);
 351 }
 352
 353 static void __exit ds1621_exit(void)
 354 {
 355         i2c_del_driver(&ds1621_driver);
 356 }
 357
 358
 359 MODULE_AUTHOR("Christian W. Zuckschwerdt <zany@triq.net>");
 360 MODULE_DESCRIPTION("DS1621 driver");
 361 MODULE_LICENSE("GPL");
 362
 363 module_init(ds1621_init);
 364 module_exit(ds1621_exit);