drivers/hwmon/jc42.c

   1 /*
   2  * jc42.c - driver for Jedec JC42.4 compliant temperature sensors
   3  *
   4  * Copyright (c) 2010  Ericsson AB.
   5  *
   6  * Derived from lm77.c by Andras BALI <drewie@freemail.hu>.
   7  *
   8  * JC42.4 compliant temperature sensors are typically used on memory modules.
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License as published by
  12  * the Free Software Foundation; either version 2 of the License, or
  13  * (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  * GNU General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, write to the Free Software
  22  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  23  */
  24
  25 #include <linux/module.h>
  26 #include <linux/init.h>
  27 #include <linux/slab.h>
  28 #include <linux/jiffies.h>
  29 #include <linux/i2c.h>
  30 #include <linux/hwmon.h>
  31 #include <linux/hwmon-sysfs.h>
  32 #include <linux/err.h>
  33 #include <linux/mutex.h>
  34
  35 /* Addresses to scan */
  36 static const unsigned short normal_i2c[] = {
  37         0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, I2C_CLIENT_END };
  38
  39 /* JC42 registers. All registers are 16 bit. */
  40 #define JC42_REG_CAP            0x00
  41 #define JC42_REG_CONFIG         0x01
  42 #define JC42_REG_TEMP_UPPER     0x02
  43 #define JC42_REG_TEMP_LOWER     0x03
  44 #define JC42_REG_TEMP_CRITICAL  0x04
  45 #define JC42_REG_TEMP           0x05
  46 #define JC42_REG_MANID          0x06
  47 #define JC42_REG_DEVICEID       0x07
  48
  49 /* Status bits in temperature register */
  50 #define JC42_ALARM_CRIT_BIT     15
  51 #define JC42_ALARM_MAX_BIT      14
  52 #define JC42_ALARM_MIN_BIT      13
  53
  54 /* Configuration register defines */
  55 #define JC42_CFG_CRIT_ONLY      (1 << 2)
  56 #define JC42_CFG_TCRIT_LOCK     (1 << 6)
  57 #define JC42_CFG_EVENT_LOCK     (1 << 7)
  58 #define JC42_CFG_SHUTDOWN       (1 << 8)
  59 #define JC42_CFG_HYST_SHIFT     9
  60 #define JC42_CFG_HYST_MASK      (0x03 << 9)
  61
  62 /* Capabilities */
  63 #define JC42_CAP_RANGE          (1 << 2)
  64
  65 /* Manufacturer IDs */
  66 #define ADT_MANID               0x11d4  /* Analog Devices */
  67 #define ATMEL_MANID             0x001f  /* Atmel */
  68 #define MAX_MANID               0x004d  /* Maxim */
  69 #define IDT_MANID               0x00b3  /* IDT */
  70 #define MCP_MANID               0x0054  /* Microchip */
  71 #define NXP_MANID               0x1131  /* NXP Semiconductors */
  72 #define ONS_MANID               0x1b09  /* ON Semiconductor */
  73 #define STM_MANID               0x104a  /* ST Microelectronics */
  74
  75 /* Supported chips */
  76
  77 /* Analog Devices */
  78 #define ADT7408_DEVID           0x0801
  79 #define ADT7408_DEVID_MASK      0xffff
  80
  81 /* Atmel */
  82 #define AT30TS00_DEVID          0x8201
  83 #define AT30TS00_DEVID_MASK     0xffff
  84
  85 /* IDT */
  86 #define TS3000B3_DEVID          0x2903  /* Also matches TSE2002B3 */
  87 #define TS3000B3_DEVID_MASK     0xffff
  88
  89 #define TS3000GB2_DEVID         0x2912  /* Also matches TSE2002GB2 */
  90 #define TS3000GB2_DEVID_MASK    0xffff
  91
  92 /* Maxim */
  93 #define MAX6604_DEVID           0x3e00
  94 #define MAX6604_DEVID_MASK      0xffff
  95
  96 /* Microchip */
  97 #define MCP9804_DEVID           0x0200
  98 #define MCP9804_DEVID_MASK      0xfffc
  99
 100 #define MCP98242_DEVID          0x2000
 101 #define MCP98242_DEVID_MASK     0xfffc
 102
 103 #define MCP98243_DEVID          0x2100
 104 #define MCP98243_DEVID_MASK     0xfffc
 105
 106 #define MCP9843_DEVID           0x0000  /* Also matches mcp9805 */
 107 #define MCP9843_DEVID_MASK      0xfffe
 108
 109 /* NXP */
 110 #define SE97_DEVID              0xa200
 111 #define SE97_DEVID_MASK         0xfffc
 112
 113 #define SE98_DEVID              0xa100
 114 #define SE98_DEVID_MASK         0xfffc
 115
 116 /* ON Semiconductor */
 117 #define CAT6095_DEVID           0x0800  /* Also matches CAT34TS02 */
 118 #define CAT6095_DEVID_MASK      0xffe0
 119
 120 /* ST Microelectronics */
 121 #define STTS424_DEVID           0x0101
 122 #define STTS424_DEVID_MASK      0xffff
 123
 124 #define STTS424E_DEVID          0x0000
 125 #define STTS424E_DEVID_MASK     0xfffe
 126
 127 #define STTS2002_DEVID          0x0300
 128 #define STTS2002_DEVID_MASK     0xffff
 129
 130 #define STTS3000_DEVID          0x0200
 131 #define STTS3000_DEVID_MASK     0xffff
 132
 133 static u16 jc42_hysteresis[] = { 0, 1500, 3000, 6000 };
 134
 135 struct jc42_chips {
 136         u16 manid;
 137         u16 devid;
 138         u16 devid_mask;
 139 };
 140
 141 static struct jc42_chips jc42_chips[] = {
 142         { ADT_MANID, ADT7408_DEVID, ADT7408_DEVID_MASK },
 143         { ATMEL_MANID, AT30TS00_DEVID, AT30TS00_DEVID_MASK },
 144         { IDT_MANID, TS3000B3_DEVID, TS3000B3_DEVID_MASK },
 145         { IDT_MANID, TS3000GB2_DEVID, TS3000GB2_DEVID_MASK },
 146         { MAX_MANID, MAX6604_DEVID, MAX6604_DEVID_MASK },
 147         { MCP_MANID, MCP9804_DEVID, MCP9804_DEVID_MASK },
 148         { MCP_MANID, MCP98242_DEVID, MCP98242_DEVID_MASK },
 149         { MCP_MANID, MCP98243_DEVID, MCP98243_DEVID_MASK },
 150         { MCP_MANID, MCP9843_DEVID, MCP9843_DEVID_MASK },
 151         { NXP_MANID, SE97_DEVID, SE97_DEVID_MASK },
 152         { ONS_MANID, CAT6095_DEVID, CAT6095_DEVID_MASK },
 153         { NXP_MANID, SE98_DEVID, SE98_DEVID_MASK },
 154         { STM_MANID, STTS424_DEVID, STTS424_DEVID_MASK },
 155         { STM_MANID, STTS424E_DEVID, STTS424E_DEVID_MASK },
 156         { STM_MANID, STTS2002_DEVID, STTS2002_DEVID_MASK },
 157         { STM_MANID, STTS3000_DEVID, STTS3000_DEVID_MASK },
 158 };
 159
 160 /* Each client has this additional data */
 161 struct jc42_data {
 162         struct device   *hwmon_dev;
 163         struct mutex    update_lock;    /* protect register access */
 164         bool            extended;       /* true if extended range supported */
 165         bool            valid;
 166         unsigned long   last_updated;   /* In jiffies */
 167         u16             orig_config;    /* original configuration */
 168         u16             config;         /* current configuration */
 169         u16             temp_input;     /* Temperatures */
 170         u16             temp_crit;
 171         u16             temp_min;
 172         u16             temp_max;
 173 };
 174
 175 static int jc42_probe(struct i2c_client *client,
 176                       const struct i2c_device_id *id);
 177 static int jc42_detect(struct i2c_client *client, struct i2c_board_info *info);
 178 static int jc42_remove(struct i2c_client *client);
 179
 180 static struct jc42_data *jc42_update_device(struct device *dev);
 181
 182 static const struct i2c_device_id jc42_id[] = {
 183         { "jc42", 0 },
 184         { }
 185 };
 186 MODULE_DEVICE_TABLE(i2c, jc42_id);
 187
 188 #ifdef CONFIG_PM
 189
 190 static int jc42_suspend(struct device *dev)
 191 {
 192         struct i2c_client *client = to_i2c_client(dev);
 193         struct jc42_data *data = i2c_get_clientdata(client);
 194
 195         data->config |= JC42_CFG_SHUTDOWN;
 196         i2c_smbus_write_word_swapped(client, JC42_REG_CONFIG, data->config);
 197         return 0;
 198 }
 199
 200 static int jc42_resume(struct device *dev)
 201 {
 202         struct i2c_client *client = to_i2c_client(dev);
 203         struct jc42_data *data = i2c_get_clientdata(client);
 204
 205         data->config &= ~JC42_CFG_SHUTDOWN;
 206         i2c_smbus_write_word_swapped(client, JC42_REG_CONFIG, data->config);
 207         return 0;
 208 }
 209
 210 static const struct dev_pm_ops jc42_dev_pm_ops = {
 211         .suspend = jc42_suspend,
 212         .resume = jc42_resume,
 213 };
 214
 215 #define JC42_DEV_PM_OPS (&jc42_dev_pm_ops)
 216 #else
 217 #define JC42_DEV_PM_OPS NULL
 218 #endif /* CONFIG_PM */
 219
 220 /* This is the driver that will be inserted */
 221 static struct i2c_driver jc42_driver = {
 222         .class          = I2C_CLASS_SPD,
 223         .driver = {
 224                 .name   = "jc42",
 225                 .pm = JC42_DEV_PM_OPS,
 226         },
 227         .probe          = jc42_probe,
 228         .remove         = jc42_remove,
 229         .id_table       = jc42_id,
 230         .detect         = jc42_detect,
 231         .address_list   = normal_i2c,
 232 };
 233
 234 #define JC42_TEMP_MIN_EXTENDED  (-40000)
 235 #define JC42_TEMP_MIN           0
 236 #define JC42_TEMP_MAX           125000
 237
 238 static u16 jc42_temp_to_reg(int temp, bool extended)
 239 {
 240         int ntemp = SENSORS_LIMIT(temp,
 241                                   extended ? JC42_TEMP_MIN_EXTENDED :
 242                                   JC42_TEMP_MIN, JC42_TEMP_MAX);
 243
 244         /* convert from 0.001 to 0.0625 resolution */
 245         return (ntemp * 2 / 125) & 0x1fff;
 246 }
 247
 248 static int jc42_temp_from_reg(s16 reg)
 249 {
 250         reg &= 0x1fff;
 251
 252         /* sign extend register */
 253         if (reg & 0x1000)
 254                 reg |= 0xf000;
 255
 256         /* convert from 0.0625 to 0.001 resolution */
 257         return reg * 125 / 2;
 258 }
 259
 260 /* sysfs stuff */
 261
 262 /* read routines for temperature limits */
 263 #define show(value)     \
 264 static ssize_t show_##value(struct device *dev,                         \
 265                             struct device_attribute *attr,              \
 266                             char *buf)                                  \
 267 {                                                                       \
 268         struct jc42_data *data = jc42_update_device(dev);               \
 269         if (IS_ERR(data))                                               \
 270                 return PTR_ERR(data);                                   \
 271         return sprintf(buf, "%d\n", jc42_temp_from_reg(data->value));   \
 272 }
 273
 274 show(temp_input);
 275 show(temp_crit);
 276 show(temp_min);
 277 show(temp_max);
 278
 279 /* read routines for hysteresis values */
 280 static ssize_t show_temp_crit_hyst(struct device *dev,
 281                                    struct device_attribute *attr, char *buf)
 282 {
 283         struct jc42_data *data = jc42_update_device(dev);
 284         int temp, hyst;
 285
 286         if (IS_ERR(data))
 287                 return PTR_ERR(data);
 288
 289         temp = jc42_temp_from_reg(data->temp_crit);
 290         hyst = jc42_hysteresis[(data->config & JC42_CFG_HYST_MASK)
 291                                >> JC42_CFG_HYST_SHIFT];
 292         return sprintf(buf, "%d\n", temp - hyst);
 293 }
 294
 295 static ssize_t show_temp_max_hyst(struct device *dev,
 296                                   struct device_attribute *attr, char *buf)
 297 {
 298         struct jc42_data *data = jc42_update_device(dev);
 299         int temp, hyst;
 300
 301         if (IS_ERR(data))
 302                 return PTR_ERR(data);
 303
 304         temp = jc42_temp_from_reg(data->temp_max);
 305         hyst = jc42_hysteresis[(data->config & JC42_CFG_HYST_MASK)
 306                                >> JC42_CFG_HYST_SHIFT];
 307         return sprintf(buf, "%d\n", temp - hyst);
 308 }
 309
 310 /* write routines */
 311 #define set(value, reg) \
 312 static ssize_t set_##value(struct device *dev,                          \
 313                            struct device_attribute *attr,               \
 314                            const char *buf, size_t count)               \
 315 {                                                                       \
 316         struct i2c_client *client = to_i2c_client(dev);                 \
 317         struct jc42_data *data = i2c_get_clientdata(client);            \
 318         int err, ret = count;                                           \
 319         long val;                                                       \
 320         if (kstrtol(buf, 10, &val) < 0)                         \
 321                 return -EINVAL;                                         \
 322         mutex_lock(&data->update_lock);                                 \
 323         data->value = jc42_temp_to_reg(val, data->extended);            \
 324         err = i2c_smbus_write_word_swapped(client, reg, data->value);   \
 325         if (err < 0)                                                    \
 326                 ret = err;                                              \
 327         mutex_unlock(&data->update_lock);                               \
 328         return ret;                                                     \
 329 }
 330
 331 set(temp_min, JC42_REG_TEMP_LOWER);
 332 set(temp_max, JC42_REG_TEMP_UPPER);
 333 set(temp_crit, JC42_REG_TEMP_CRITICAL);
 334
 335 /*
 336  * JC42.4 compliant chips only support four hysteresis values.
 337  * Pick best choice and go from there.
 338  */
 339 static ssize_t set_temp_crit_hyst(struct device *dev,
 340                                   struct device_attribute *attr,
 341                                   const char *buf, size_t count)
 342 {
 343         struct i2c_client *client = to_i2c_client(dev);
 344         struct jc42_data *data = i2c_get_clientdata(client);
 345         unsigned long val;
 346         int diff, hyst;
 347         int err;
 348         int ret = count;
 349
 350         if (kstrtoul(buf, 10, &val) < 0)
 351                 return -EINVAL;
 352
 353         diff = jc42_temp_from_reg(data->temp_crit) - val;
 354         hyst = 0;
 355         if (diff > 0) {
 356                 if (diff < 2250)
 357                         hyst = 1;       /* 1.5 degrees C */
 358                 else if (diff < 4500)
 359                         hyst = 2;       /* 3.0 degrees C */
 360                 else
 361                         hyst = 3;       /* 6.0 degrees C */
 362         }
 363
 364         mutex_lock(&data->update_lock);
 365         data->config = (data->config & ~JC42_CFG_HYST_MASK)
 366           | (hyst << JC42_CFG_HYST_SHIFT);
 367         err = i2c_smbus_write_word_swapped(client, JC42_REG_CONFIG,
 368                                            data->config);
 369         if (err < 0)
 370                 ret = err;
 371         mutex_unlock(&data->update_lock);
 372         return ret;
 373 }
 374
 375 static ssize_t show_alarm(struct device *dev,
 376                           struct device_attribute *attr, char *buf)
 377 {
 378         u16 bit = to_sensor_dev_attr(attr)->index;
 379         struct jc42_data *data = jc42_update_device(dev);
 380         u16 val;
 381
 382         if (IS_ERR(data))
 383                 return PTR_ERR(data);
 384
 385         val = data->temp_input;
 386         if (bit != JC42_ALARM_CRIT_BIT && (data->config & JC42_CFG_CRIT_ONLY))
 387                 val = 0;
 388         return sprintf(buf, "%u\n", (val >> bit) & 1);
 389 }
 390
 391 static DEVICE_ATTR(temp1_input, S_IRUGO,
 392                    show_temp_input, NULL);
 393 static DEVICE_ATTR(temp1_crit, S_IRUGO,
 394                    show_temp_crit, set_temp_crit);
 395 static DEVICE_ATTR(temp1_min, S_IRUGO,
 396                    show_temp_min, set_temp_min);
 397 static DEVICE_ATTR(temp1_max, S_IRUGO,
 398                    show_temp_max, set_temp_max);
 399
 400 static DEVICE_ATTR(temp1_crit_hyst, S_IRUGO,
 401                    show_temp_crit_hyst, set_temp_crit_hyst);
 402 static DEVICE_ATTR(temp1_max_hyst, S_IRUGO,
 403                    show_temp_max_hyst, NULL);
 404
 405 static SENSOR_DEVICE_ATTR(temp1_crit_alarm, S_IRUGO, show_alarm, NULL,
 406                           JC42_ALARM_CRIT_BIT);
 407 static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL,
 408                           JC42_ALARM_MIN_BIT);
 409 static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL,
 410                           JC42_ALARM_MAX_BIT);
 411
 412 static struct attribute *jc42_attributes[] = {
 413         &dev_attr_temp1_input.attr,
 414         &dev_attr_temp1_crit.attr,
 415         &dev_attr_temp1_min.attr,
 416         &dev_attr_temp1_max.attr,
 417         &dev_attr_temp1_crit_hyst.attr,
 418         &dev_attr_temp1_max_hyst.attr,
 419         &sensor_dev_attr_temp1_crit_alarm.dev_attr.attr,
 420         &sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
 421         &sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
 422         NULL
 423 };
 424
 425 static umode_t jc42_attribute_mode(struct kobject *kobj,
 426                                   struct attribute *attr, int index)
 427 {
 428         struct device *dev = container_of(kobj, struct device, kobj);
 429         struct i2c_client *client = to_i2c_client(dev);
 430         struct jc42_data *data = i2c_get_clientdata(client);
 431         unsigned int config = data->config;
 432         bool readonly;
 433
 434         if (attr == &dev_attr_temp1_crit.attr)
 435                 readonly = config & JC42_CFG_TCRIT_LOCK;
 436         else if (attr == &dev_attr_temp1_min.attr ||
 437                  attr == &dev_attr_temp1_max.attr)
 438                 readonly = config & JC42_CFG_EVENT_LOCK;
 439         else if (attr == &dev_attr_temp1_crit_hyst.attr)
 440                 readonly = config & (JC42_CFG_EVENT_LOCK | JC42_CFG_TCRIT_LOCK);
 441         else
 442                 readonly = true;
 443
 444         return S_IRUGO | (readonly ? 0 : S_IWUSR);
 445 }
 446
 447 static const struct attribute_group jc42_group = {
 448         .attrs = jc42_attributes,
 449         .is_visible = jc42_attribute_mode,
 450 };
 451
 452 /* Return 0 if detection is successful, -ENODEV otherwise */
 453 static int jc42_detect(struct i2c_client *client, struct i2c_board_info *info)
 454 {
 455         struct i2c_adapter *adapter = client->adapter;
 456         int i, config, cap, manid, devid;
 457
 458         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
 459                                      I2C_FUNC_SMBUS_WORD_DATA))
 460                 return -ENODEV;
 461
 462         cap = i2c_smbus_read_word_swapped(client, JC42_REG_CAP);
 463         config = i2c_smbus_read_word_swapped(client, JC42_REG_CONFIG);
 464         manid = i2c_smbus_read_word_swapped(client, JC42_REG_MANID);
 465         devid = i2c_smbus_read_word_swapped(client, JC42_REG_DEVICEID);
 466
 467         if (cap < 0 || config < 0 || manid < 0 || devid < 0)
 468                 return -ENODEV;
 469
 470         if ((cap & 0xff00) || (config & 0xf800))
 471                 return -ENODEV;
 472
 473         for (i = 0; i < ARRAY_SIZE(jc42_chips); i++) {
 474                 struct jc42_chips *chip = &jc42_chips[i];
 475                 if (manid == chip->manid &&
 476                     (devid & chip->devid_mask) == chip->devid) {
 477                         strlcpy(info->type, "jc42", I2C_NAME_SIZE);
 478                         return 0;
 479                 }
 480         }
 481         return -ENODEV;
 482 }
 483
 484 static int jc42_probe(struct i2c_client *client, const struct i2c_device_id *id)
 485 {
 486         struct jc42_data *data;
 487         int config, cap, err;
 488         struct device *dev = &client->dev;
 489
 490         data = devm_kzalloc(dev, sizeof(struct jc42_data), GFP_KERNEL);
 491         if (!data)
 492                 return -ENOMEM;
 493
 494         i2c_set_clientdata(client, data);
 495         mutex_init(&data->update_lock);
 496
 497         cap = i2c_smbus_read_word_swapped(client, JC42_REG_CAP);
 498         if (cap < 0)
 499                 return cap;
 500
 501         data->extended = !!(cap & JC42_CAP_RANGE);
 502
 503         config = i2c_smbus_read_word_swapped(client, JC42_REG_CONFIG);
 504         if (config < 0)
 505                 return config;
 506
 507         data->orig_config = config;
 508         if (config & JC42_CFG_SHUTDOWN) {
 509                 config &= ~JC42_CFG_SHUTDOWN;
 510                 i2c_smbus_write_word_swapped(client, JC42_REG_CONFIG, config);
 511         }
 512         data->config = config;
 513
 514         /* Register sysfs hooks */
 515         err = sysfs_create_group(&dev->kobj, &jc42_group);
 516         if (err)
 517                 return err;
 518
 519         data->hwmon_dev = hwmon_device_register(dev);
 520         if (IS_ERR(data->hwmon_dev)) {
 521                 err = PTR_ERR(data->hwmon_dev);
 522                 goto exit_remove;
 523         }
 524
 525         return 0;
 526
 527 exit_remove:
 528         sysfs_remove_group(&dev->kobj, &jc42_group);
 529         return err;
 530 }
 531
 532 static int jc42_remove(struct i2c_client *client)
 533 {
 534         struct jc42_data *data = i2c_get_clientdata(client);
 535         hwmon_device_unregister(data->hwmon_dev);
 536         sysfs_remove_group(&client->dev.kobj, &jc42_group);
 537
 538         /* Restore original configuration except hysteresis */
 539         if ((data->config & ~JC42_CFG_HYST_MASK) !=
 540             (data->orig_config & ~JC42_CFG_HYST_MASK)) {
 541                 int config;
 542
 543                 config = (data->orig_config & ~JC42_CFG_HYST_MASK)
 544                   | (data->config & JC42_CFG_HYST_MASK);
 545                 i2c_smbus_write_word_swapped(client, JC42_REG_CONFIG, config);
 546         }
 547         return 0;
 548 }
 549
 550 static struct jc42_data *jc42_update_device(struct device *dev)
 551 {
 552         struct i2c_client *client = to_i2c_client(dev);
 553         struct jc42_data *data = i2c_get_clientdata(client);
 554         struct jc42_data *ret = data;
 555         int val;
 556
 557         mutex_lock(&data->update_lock);
 558
 559         if (time_after(jiffies, data->last_updated + HZ) || !data->valid) {
 560                 val = i2c_smbus_read_word_swapped(client, JC42_REG_TEMP);
 561                 if (val < 0) {
 562                         ret = ERR_PTR(val);
 563                         goto abort;
 564                 }
 565                 data->temp_input = val;
 566
 567                 val = i2c_smbus_read_word_swapped(client,
 568                                                   JC42_REG_TEMP_CRITICAL);
 569                 if (val < 0) {
 570                         ret = ERR_PTR(val);
 571                         goto abort;
 572                 }
 573                 data->temp_crit = val;
 574
 575                 val = i2c_smbus_read_word_swapped(client, JC42_REG_TEMP_LOWER);
 576                 if (val < 0) {
 577                         ret = ERR_PTR(val);
 578                         goto abort;
 579                 }
 580                 data->temp_min = val;
 581
 582                 val = i2c_smbus_read_word_swapped(client, JC42_REG_TEMP_UPPER);
 583                 if (val < 0) {
 584                         ret = ERR_PTR(val);
 585                         goto abort;
 586                 }
 587                 data->temp_max = val;
 588
 589                 data->last_updated = jiffies;
 590                 data->valid = true;
 591         }
 592 abort:
 593         mutex_unlock(&data->update_lock);
 594         return ret;
 595 }
 596
 597 module_i2c_driver(jc42_driver);
 598
 599 MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>");
 600 MODULE_DESCRIPTION("JC42 driver");
 601 MODULE_LICENSE("GPL");