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