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/hwmon-sysfs.h>
  31 #include <linux/err.h>
  32 #include <linux/mutex.h>
  33 #include <linux/sysfs.h>
  34 #include "lm75.h"
  35
  36 /* Addresses to scan */
  37 static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c,
  38                                         0x4d, 0x4e, 0x4f, I2C_CLIENT_END };
  39
  40 /* Insmod parameters */
  41 I2C_CLIENT_INSMOD_1(ds1621);
  42 static int polarity = -1;
  43 module_param(polarity, int, 0);
  44 MODULE_PARM_DESC(polarity, "Output's polarity: 0 = active high, 1 = active low");
  45
  46 /* Many DS1621 constants specified below */
  47 /* Config register used for detection         */
  48 /*  7    6    5    4    3    2    1    0      */
  49 /* |Done|THF |TLF |NVB | X  | X  |POL |1SHOT| */
  50 #define DS1621_REG_CONFIG_NVB           0x10
  51 #define DS1621_REG_CONFIG_POLARITY      0x02
  52 #define DS1621_REG_CONFIG_1SHOT         0x01
  53 #define DS1621_REG_CONFIG_DONE          0x80
  54
  55 /* The DS1621 registers */
  56 static const u8 DS1621_REG_TEMP[3] = {
  57         0xAA,           /* input, word, RO */
  58         0xA2,           /* min, word, RW */
  59         0xA1,           /* max, word, RW */
  60 };
  61 #define DS1621_REG_CONF                 0xAC /* byte, RW */
  62 #define DS1621_COM_START                0xEE /* no data */
  63 #define DS1621_COM_STOP                 0x22 /* no data */
  64
  65 /* The DS1621 configuration register */
  66 #define DS1621_ALARM_TEMP_HIGH          0x40
  67 #define DS1621_ALARM_TEMP_LOW           0x20
  68
  69 /* Conversions */
  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 device *hwmon_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[3];                    /* Register values, word */
  81         u8 conf;                        /* Register encoding, combined */
  82 };
  83
  84 static int ds1621_probe(struct i2c_client *client,
  85                         const struct i2c_device_id *id);
  86 static int ds1621_detect(struct i2c_client *client, int kind,
  87                          struct i2c_board_info *info);
  88 static void ds1621_init_client(struct i2c_client *client);
  89 static int ds1621_remove(struct i2c_client *client);
  90 static struct ds1621_data *ds1621_update_client(struct device *dev);
  91
  92 static const struct i2c_device_id ds1621_id[] = {
  93         { "ds1621", ds1621 },
  94         { "ds1625", ds1621 },
  95         { }
  96 };
  97 MODULE_DEVICE_TABLE(i2c, ds1621_id);
  98
  99 /* This is the driver that will be inserted */
 100 static struct i2c_driver ds1621_driver = {
 101         .class          = I2C_CLASS_HWMON,
 102         .driver = {
 103                 .name   = "ds1621",
 104         },
 105         .probe          = ds1621_probe,
 106         .remove         = ds1621_remove,
 107         .id_table       = ds1621_id,
 108         .detect         = ds1621_detect,
 109         .address_data   = &addr_data,
 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 SMBus standard. */
 115 static int ds1621_read_value(struct i2c_client *client, u8 reg)
 116 {
 117         if (reg == DS1621_REG_CONF)
 118                 return i2c_smbus_read_byte_data(client, reg);
 119         else
 120                 return swab16(i2c_smbus_read_word_data(client, reg));
 121 }
 122
 123 static int ds1621_write_value(struct i2c_client *client, u8 reg, u16 value)
 124 {
 125         if (reg == DS1621_REG_CONF)
 126                 return i2c_smbus_write_byte_data(client, reg, value);
 127         else
 128                 return i2c_smbus_write_word_data(client, reg, swab16(value));
 129 }
 130
 131 static void ds1621_init_client(struct i2c_client *client)
 132 {
 133         int reg = ds1621_read_value(client, DS1621_REG_CONF);
 134         /* switch to continuous conversion mode */
 135         reg &= ~ DS1621_REG_CONFIG_1SHOT;
 136
 137         /* setup output polarity */
 138         if (polarity == 0)
 139                 reg &= ~DS1621_REG_CONFIG_POLARITY;
 140         else if (polarity == 1)
 141                 reg |= DS1621_REG_CONFIG_POLARITY;
 142
 143         ds1621_write_value(client, DS1621_REG_CONF, reg);
 144
 145         /* start conversion */
 146         i2c_smbus_write_byte(client, DS1621_COM_START);
 147 }
 148
 149 static ssize_t show_temp(struct device *dev, struct device_attribute *da,
 150                          char *buf)
 151 {
 152         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 153         struct ds1621_data *data = ds1621_update_client(dev);
 154         return sprintf(buf, "%d\n",
 155                        LM75_TEMP_FROM_REG(data->temp[attr->index]));
 156 }
 157
 158 static ssize_t set_temp(struct device *dev, struct device_attribute *da,
 159                         const char *buf, size_t count)
 160 {
 161         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 162         struct i2c_client *client = to_i2c_client(dev);
 163         struct ds1621_data *data = ds1621_update_client(dev);
 164         u16 val = LM75_TEMP_TO_REG(simple_strtol(buf, NULL, 10));
 165
 166         mutex_lock(&data->update_lock);
 167         data->temp[attr->index] = val;
 168         ds1621_write_value(client, DS1621_REG_TEMP[attr->index],
 169                            data->temp[attr->index]);
 170         mutex_unlock(&data->update_lock);
 171         return count;
 172 }
 173
 174 static ssize_t show_alarms(struct device *dev, struct device_attribute *da,
 175                            char *buf)
 176 {
 177         struct ds1621_data *data = ds1621_update_client(dev);
 178         return sprintf(buf, "%d\n", ALARMS_FROM_REG(data->conf));
 179 }
 180
 181 static ssize_t show_alarm(struct device *dev, struct device_attribute *da,
 182                           char *buf)
 183 {
 184         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 185         struct ds1621_data *data = ds1621_update_client(dev);
 186         return sprintf(buf, "%d\n", !!(data->conf & attr->index));
 187 }
 188
 189 static DEVICE_ATTR(alarms, S_IRUGO, show_alarms, NULL);
 190 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0);
 191 static SENSOR_DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO, show_temp, set_temp, 1);
 192 static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp, set_temp, 2);
 193 static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL,
 194                 DS1621_ALARM_TEMP_LOW);
 195 static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL,
 196                 DS1621_ALARM_TEMP_HIGH);
 197
 198 static struct attribute *ds1621_attributes[] = {
 199         &sensor_dev_attr_temp1_input.dev_attr.attr,
 200         &sensor_dev_attr_temp1_min.dev_attr.attr,
 201         &sensor_dev_attr_temp1_max.dev_attr.attr,
 202         &sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
 203         &sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
 204         &dev_attr_alarms.attr,
 205         NULL
 206 };
 207
 208 static const struct attribute_group ds1621_group = {
 209         .attrs = ds1621_attributes,
 210 };
 211
 212
 213 /* Return 0 if detection is successful, -ENODEV otherwise */
 214 static int ds1621_detect(struct i2c_client *client, int kind,
 215                          struct i2c_board_info *info)
 216 {
 217         struct i2c_adapter *adapter = client->adapter;
 218         int conf, temp;
 219         int i;
 220
 221         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA
 222                                      | I2C_FUNC_SMBUS_WORD_DATA
 223                                      | I2C_FUNC_SMBUS_WRITE_BYTE))
 224                 return -ENODEV;
 225
 226         /* Now, we do the remaining detection. It is lousy. */
 227         if (kind < 0) {
 228                 /* The NVB bit should be low if no EEPROM write has been
 229                    requested during the latest 10ms, which is highly
 230                    improbable in our case. */
 231                 conf = ds1621_read_value(client, DS1621_REG_CONF);
 232                 if (conf & DS1621_REG_CONFIG_NVB)
 233                         return -ENODEV;
 234                 /* The 7 lowest bits of a temperature should always be 0. */
 235                 for (i = 0; i < ARRAY_SIZE(DS1621_REG_TEMP); i++) {
 236                         temp = ds1621_read_value(client, DS1621_REG_TEMP[i]);
 237                         if (temp & 0x007f)
 238                                 return -ENODEV;
 239                 }
 240         }
 241
 242         strlcpy(info->type, "ds1621", I2C_NAME_SIZE);
 243
 244         return 0;
 245 }
 246
 247 static int ds1621_probe(struct i2c_client *client,
 248                         const struct i2c_device_id *id)
 249 {
 250         struct ds1621_data *data;
 251         int err;
 252
 253         data = kzalloc(sizeof(struct ds1621_data), GFP_KERNEL);
 254         if (!data) {
 255                 err = -ENOMEM;
 256                 goto exit;
 257         }
 258
 259         i2c_set_clientdata(client, data);
 260         mutex_init(&data->update_lock);
 261
 262         /* Initialize the DS1621 chip */
 263         ds1621_init_client(client);
 264
 265         /* Register sysfs hooks */
 266         if ((err = sysfs_create_group(&client->dev.kobj, &ds1621_group)))
 267                 goto exit_free;
 268
 269         data->hwmon_dev = hwmon_device_register(&client->dev);
 270         if (IS_ERR(data->hwmon_dev)) {
 271                 err = PTR_ERR(data->hwmon_dev);
 272                 goto exit_remove_files;
 273         }
 274
 275         return 0;
 276
 277       exit_remove_files:
 278         sysfs_remove_group(&client->dev.kobj, &ds1621_group);
 279       exit_free:
 280         kfree(data);
 281       exit:
 282         return err;
 283 }
 284
 285 static int ds1621_remove(struct i2c_client *client)
 286 {
 287         struct ds1621_data *data = i2c_get_clientdata(client);
 288
 289         hwmon_device_unregister(data->hwmon_dev);
 290         sysfs_remove_group(&client->dev.kobj, &ds1621_group);
 291
 292         kfree(data);
 293
 294         return 0;
 295 }
 296
 297
 298 static struct ds1621_data *ds1621_update_client(struct device *dev)
 299 {
 300         struct i2c_client *client = to_i2c_client(dev);
 301         struct ds1621_data *data = i2c_get_clientdata(client);
 302         u8 new_conf;
 303
 304         mutex_lock(&data->update_lock);
 305
 306         if (time_after(jiffies, data->last_updated + HZ + HZ / 2)
 307             || !data->valid) {
 308                 int i;
 309
 310                 dev_dbg(&client->dev, "Starting ds1621 update\n");
 311
 312                 data->conf = ds1621_read_value(client, DS1621_REG_CONF);
 313
 314                 for (i = 0; i < ARRAY_SIZE(data->temp); i++)
 315                         data->temp[i] = ds1621_read_value(client,
 316                                                           DS1621_REG_TEMP[i]);
 317
 318                 /* reset alarms if necessary */
 319                 new_conf = data->conf;
 320                 if (data->temp[0] > data->temp[1])      /* input > min */
 321                         new_conf &= ~DS1621_ALARM_TEMP_LOW;
 322                 if (data->temp[0] < data->temp[2])      /* input < max */
 323                         new_conf &= ~DS1621_ALARM_TEMP_HIGH;
 324                 if (data->conf != new_conf)
 325                         ds1621_write_value(client, DS1621_REG_CONF,
 326                                            new_conf);
 327
 328                 data->last_updated = jiffies;
 329                 data->valid = 1;
 330         }
 331
 332         mutex_unlock(&data->update_lock);
 333
 334         return data;
 335 }
 336
 337 static int __init ds1621_init(void)
 338 {
 339         return i2c_add_driver(&ds1621_driver);
 340 }
 341
 342 static void __exit ds1621_exit(void)
 343 {
 344         i2c_del_driver(&ds1621_driver);
 345 }
 346
 347
 348 MODULE_AUTHOR("Christian W. Zuckschwerdt <zany@triq.net>");
 349 MODULE_DESCRIPTION("DS1621 driver");
 350 MODULE_LICENSE("GPL");
 351
 352 module_init(ds1621_init);
 353 module_exit(ds1621_exit);