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             0xA2 /* word, RW */
  57 #define DS1621_REG_TEMP_MAX             0xA1 /* 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 */
  67 #define ALARMS_FROM_REG(val) ((val) & \
  68                               (DS1621_ALARM_TEMP_HIGH | DS1621_ALARM_TEMP_LOW))
  69
  70 /* Each client has this additional data */
  71 struct ds1621_data {
  72         struct i2c_client client;
  73         struct class_device *class_dev;
  74         struct mutex update_lock;
  75         char valid;                     /* !=0 if following fields are valid */
  76         unsigned long last_updated;     /* In jiffies */
  77
  78         u16 temp, temp_min, temp_max;   /* Register values, word */
  79         u8 conf;                        /* Register encoding, combined */
  80 };
  81
  82 static int ds1621_attach_adapter(struct i2c_adapter *adapter);
  83 static int ds1621_detect(struct i2c_adapter *adapter, int address,
  84                          int kind);
  85 static void ds1621_init_client(struct i2c_client *client);
  86 static int ds1621_detach_client(struct i2c_client *client);
  87 static struct ds1621_data *ds1621_update_client(struct device *dev);
  88
  89 /* This is the driver that will be inserted */
  90 static struct i2c_driver ds1621_driver = {
  91         .driver = {
  92                 .name   = "ds1621",
  93         },
  94         .id             = I2C_DRIVERID_DS1621,
  95         .attach_adapter = ds1621_attach_adapter,
  96         .detach_client  = ds1621_detach_client,
  97 };
  98
  99 /* All registers are word-sized, except for the configuration register.
 100    DS1621 uses a high-byte first convention, which is exactly opposite to
 101    the SMBus standard. */
 102 static int ds1621_read_value(struct i2c_client *client, u8 reg)
 103 {
 104         if (reg == DS1621_REG_CONF)
 105                 return i2c_smbus_read_byte_data(client, reg);
 106         else
 107                 return swab16(i2c_smbus_read_word_data(client, reg));
 108 }
 109
 110 static int ds1621_write_value(struct i2c_client *client, u8 reg, u16 value)
 111 {
 112         if (reg == DS1621_REG_CONF)
 113                 return i2c_smbus_write_byte_data(client, reg, value);
 114         else
 115                 return i2c_smbus_write_word_data(client, reg, swab16(value));
 116 }
 117
 118 static void ds1621_init_client(struct i2c_client *client)
 119 {
 120         int reg = ds1621_read_value(client, DS1621_REG_CONF);
 121         /* switch to continuous conversion mode */
 122         reg &= ~ DS1621_REG_CONFIG_1SHOT;
 123
 124         /* setup output polarity */
 125         if (polarity == 0)
 126                 reg &= ~DS1621_REG_CONFIG_POLARITY;
 127         else if (polarity == 1)
 128                 reg |= DS1621_REG_CONFIG_POLARITY;
 129
 130         ds1621_write_value(client, DS1621_REG_CONF, reg);
 131
 132         /* start conversion */
 133         i2c_smbus_write_byte(client, DS1621_COM_START);
 134 }
 135
 136 #define show(value)                                                     \
 137 static ssize_t show_##value(struct device *dev, struct device_attribute *attr, char *buf)               \
 138 {                                                                       \
 139         struct ds1621_data *data = ds1621_update_client(dev);           \
 140         return sprintf(buf, "%d\n", LM75_TEMP_FROM_REG(data->value));   \
 141 }
 142
 143 show(temp);
 144 show(temp_min);
 145 show(temp_max);
 146
 147 #define set_temp(suffix, value, reg)                                    \
 148 static ssize_t set_temp_##suffix(struct device *dev, struct device_attribute *attr, const char *buf,    \
 149                                  size_t count)                          \
 150 {                                                                       \
 151         struct i2c_client *client = to_i2c_client(dev);                 \
 152         struct ds1621_data *data = ds1621_update_client(dev);           \
 153         u16 val = LM75_TEMP_TO_REG(simple_strtoul(buf, NULL, 10));      \
 154                                                                         \
 155         mutex_lock(&data->update_lock);                                 \
 156         data->value = val;                                              \
 157         ds1621_write_value(client, reg, data->value);                   \
 158         mutex_unlock(&data->update_lock);                               \
 159         return count;                                                   \
 160 }
 161
 162 set_temp(min, temp_min, DS1621_REG_TEMP_MIN);
 163 set_temp(max, temp_max, DS1621_REG_TEMP_MAX);
 164
 165 static ssize_t show_alarms(struct device *dev, struct device_attribute *attr, char *buf)
 166 {
 167         struct ds1621_data *data = ds1621_update_client(dev);
 168         return sprintf(buf, "%d\n", ALARMS_FROM_REG(data->conf));
 169 }
 170
 171 static DEVICE_ATTR(alarms, S_IRUGO, show_alarms, NULL);
 172 static DEVICE_ATTR(temp1_input, S_IRUGO , show_temp, NULL);
 173 static DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO , show_temp_min, set_temp_min);
 174 static DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp_max, set_temp_max);
 175
 176 static struct attribute *ds1621_attributes[] = {
 177         &dev_attr_temp1_input.attr,
 178         &dev_attr_temp1_min.attr,
 179         &dev_attr_temp1_max.attr,
 180         &dev_attr_alarms.attr,
 181         NULL
 182 };
 183
 184 static const struct attribute_group ds1621_group = {
 185         .attrs = ds1621_attributes,
 186 };
 187
 188
 189 static int ds1621_attach_adapter(struct i2c_adapter *adapter)
 190 {
 191         if (!(adapter->class & I2C_CLASS_HWMON))
 192                 return 0;
 193         return i2c_probe(adapter, &addr_data, ds1621_detect);
 194 }
 195
 196 /* This function is called by i2c_probe */
 197 static int ds1621_detect(struct i2c_adapter *adapter, int address,
 198                          int kind)
 199 {
 200         int conf, temp;
 201         struct i2c_client *client;
 202         struct ds1621_data *data;
 203         int err = 0;
 204
 205         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA
 206                                      | I2C_FUNC_SMBUS_WORD_DATA
 207                                      | I2C_FUNC_SMBUS_WRITE_BYTE))
 208                 goto exit;
 209
 210         /* OK. For now, we presume we have a valid client. We now create the
 211            client structure, even though we cannot fill it completely yet.
 212            But it allows us to access ds1621_{read,write}_value. */
 213         if (!(data = kzalloc(sizeof(struct ds1621_data), GFP_KERNEL))) {
 214                 err = -ENOMEM;
 215                 goto exit;
 216         }
 217
 218         client = &data->client;
 219         i2c_set_clientdata(client, data);
 220         client->addr = address;
 221         client->adapter = adapter;
 222         client->driver = &ds1621_driver;
 223
 224         /* Now, we do the remaining detection. It is lousy. */
 225         if (kind < 0) {
 226                 /* The NVB bit should be low if no EEPROM write has been
 227                    requested during the latest 10ms, which is highly
 228                    improbable in our case. */
 229                 conf = ds1621_read_value(client, DS1621_REG_CONF);
 230                 if (conf & DS1621_REG_CONFIG_NVB)
 231                         goto exit_free;
 232                 /* The 7 lowest bits of a temperature should always be 0. */
 233                 temp = ds1621_read_value(client, DS1621_REG_TEMP);
 234                 if (temp & 0x007f)
 235                         goto exit_free;
 236                 temp = ds1621_read_value(client, DS1621_REG_TEMP_MIN);
 237                 if (temp & 0x007f)
 238                         goto exit_free;
 239                 temp = ds1621_read_value(client, DS1621_REG_TEMP_MAX);
 240                 if (temp & 0x007f)
 241                         goto exit_free;
 242         }
 243
 244         /* Fill in remaining client fields and put it into the global list */
 245         strlcpy(client->name, "ds1621", I2C_NAME_SIZE);
 246         mutex_init(&data->update_lock);
 247
 248         /* Tell the I2C layer a new client has arrived */
 249         if ((err = i2c_attach_client(client)))
 250                 goto exit_free;
 251
 252         /* Initialize the DS1621 chip */
 253         ds1621_init_client(client);
 254
 255         /* Register sysfs hooks */
 256         if ((err = sysfs_create_group(&client->dev.kobj, &ds1621_group)))
 257                 goto exit_detach;
 258
 259         data->class_dev = hwmon_device_register(&client->dev);
 260         if (IS_ERR(data->class_dev)) {
 261                 err = PTR_ERR(data->class_dev);
 262                 goto exit_remove_files;
 263         }
 264
 265         return 0;
 266
 267       exit_remove_files:
 268         sysfs_remove_group(&client->dev.kobj, &ds1621_group);
 269       exit_detach:
 270         i2c_detach_client(client);
 271       exit_free:
 272         kfree(data);
 273       exit:
 274         return err;
 275 }
 276
 277 static int ds1621_detach_client(struct i2c_client *client)
 278 {
 279         struct ds1621_data *data = i2c_get_clientdata(client);
 280         int err;
 281
 282         hwmon_device_unregister(data->class_dev);
 283         sysfs_remove_group(&client->dev.kobj, &ds1621_group);
 284
 285         if ((err = i2c_detach_client(client)))
 286                 return err;
 287
 288         kfree(data);
 289
 290         return 0;
 291 }
 292
 293
 294 static struct ds1621_data *ds1621_update_client(struct device *dev)
 295 {
 296         struct i2c_client *client = to_i2c_client(dev);
 297         struct ds1621_data *data = i2c_get_clientdata(client);
 298         u8 new_conf;
 299
 300         mutex_lock(&data->update_lock);
 301
 302         if (time_after(jiffies, data->last_updated + HZ + HZ / 2)
 303             || !data->valid) {
 304
 305                 dev_dbg(&client->dev, "Starting ds1621 update\n");
 306
 307                 data->conf = ds1621_read_value(client, DS1621_REG_CONF);
 308
 309                 data->temp = ds1621_read_value(client, DS1621_REG_TEMP);
 310
 311                 data->temp_min = ds1621_read_value(client,
 312                                                     DS1621_REG_TEMP_MIN);
 313                 data->temp_max = ds1621_read_value(client,
 314                                                     DS1621_REG_TEMP_MAX);
 315
 316                 /* reset alarms if necessary */
 317                 new_conf = data->conf;
 318                 if (data->temp > data->temp_min)
 319                         new_conf &= ~DS1621_ALARM_TEMP_LOW;
 320                 if (data->temp < data->temp_max)
 321                         new_conf &= ~DS1621_ALARM_TEMP_HIGH;
 322                 if (data->conf != new_conf)
 323                         ds1621_write_value(client, DS1621_REG_CONF,
 324                                            new_conf);
 325
 326                 data->last_updated = jiffies;
 327                 data->valid = 1;
 328         }
 329
 330         mutex_unlock(&data->update_lock);
 331
 332         return data;
 333 }
 334
 335 static int __init ds1621_init(void)
 336 {
 337         return i2c_add_driver(&ds1621_driver);
 338 }
 339
 340 static void __exit ds1621_exit(void)
 341 {
 342         i2c_del_driver(&ds1621_driver);
 343 }
 344
 345
 346 MODULE_AUTHOR("Christian W. Zuckschwerdt <zany@triq.net>");
 347 MODULE_DESCRIPTION("DS1621 driver");
 348 MODULE_LICENSE("GPL");
 349
 350 module_init(ds1621_init);
 351 module_exit(ds1621_exit);