drivers/hwmon/emc2103.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * emc2103.c - Support for SMSC EMC2103
   4  * Copyright (c) 2010 SMSC
   5  */
   6
   7 #include <linux/module.h>
   8 #include <linux/init.h>
   9 #include <linux/slab.h>
  10 #include <linux/jiffies.h>
  11 #include <linux/i2c.h>
  12 #include <linux/hwmon.h>
  13 #include <linux/hwmon-sysfs.h>
  14 #include <linux/err.h>
  15 #include <linux/mutex.h>
  16
  17 /* Addresses scanned */
  18 static const unsigned short normal_i2c[] = { 0x2E, I2C_CLIENT_END };
  19
  20 static const u8 REG_TEMP[4] = { 0x00, 0x02, 0x04, 0x06 };
  21 static const u8 REG_TEMP_MIN[4] = { 0x3c, 0x38, 0x39, 0x3a };
  22 static const u8 REG_TEMP_MAX[4] = { 0x34, 0x30, 0x31, 0x32 };
  23
  24 #define REG_CONF1               0x20
  25 #define REG_TEMP_MAX_ALARM      0x24
  26 #define REG_TEMP_MIN_ALARM      0x25
  27 #define REG_FAN_CONF1           0x42
  28 #define REG_FAN_TARGET_LO       0x4c
  29 #define REG_FAN_TARGET_HI       0x4d
  30 #define REG_FAN_TACH_HI         0x4e
  31 #define REG_FAN_TACH_LO         0x4f
  32 #define REG_PRODUCT_ID          0xfd
  33 #define REG_MFG_ID              0xfe
  34
  35 /* equation 4 from datasheet: rpm = (3932160 * multipler) / count */
  36 #define FAN_RPM_FACTOR          3932160
  37
  38 /*
  39  * 2103-2 and 2103-4's 3rd temperature sensor can be connected to two diodes
  40  * in anti-parallel mode, and in this configuration both can be read
  41  * independently (so we have 4 temperature inputs).  The device can't
  42  * detect if it's connected in this mode, so we have to manually enable
  43  * it.  Default is to leave the device in the state it's already in (-1).
  44  * This parameter allows APD mode to be optionally forced on or off
  45  */
  46 static int apd = -1;
  47 module_param(apd, bint, 0);
  48 MODULE_PARM_DESC(apd, "Set to zero to disable anti-parallel diode mode");
  49
  50 struct temperature {
  51         s8      degrees;
  52         u8      fraction;       /* 0-7 multiples of 0.125 */
  53 };
  54
  55 struct emc2103_data {
  56         struct i2c_client       *client;
  57         const struct            attribute_group *groups[4];
  58         struct mutex            update_lock;
  59         bool                    valid;          /* registers are valid */
  60         bool                    fan_rpm_control;
  61         int                     temp_count;     /* num of temp sensors */
  62         unsigned long           last_updated;   /* in jiffies */
  63         struct temperature      temp[4];        /* internal + 3 external */
  64         s8                      temp_min[4];    /* no fractional part */
  65         s8                      temp_max[4];    /* no fractional part */
  66         u8                      temp_min_alarm;
  67         u8                      temp_max_alarm;
  68         u8                      fan_multiplier;
  69         u16                     fan_tach;
  70         u16                     fan_target;
  71 };
  72
  73 static int read_u8_from_i2c(struct i2c_client *client, u8 i2c_reg, u8 *output)
  74 {
  75         int status = i2c_smbus_read_byte_data(client, i2c_reg);
  76         if (status < 0) {
  77                 dev_warn(&client->dev, "reg 0x%02x, err %d\n",
  78                         i2c_reg, status);
  79         } else {
  80                 *output = status;
  81         }
  82         return status;
  83 }
  84
  85 static void read_temp_from_i2c(struct i2c_client *client, u8 i2c_reg,
  86                                struct temperature *temp)
  87 {
  88         u8 degrees, fractional;
  89
  90         if (read_u8_from_i2c(client, i2c_reg, &degrees) < 0)
  91                 return;
  92
  93         if (read_u8_from_i2c(client, i2c_reg + 1, &fractional) < 0)
  94                 return;
  95
  96         temp->degrees = degrees;
  97         temp->fraction = (fractional & 0xe0) >> 5;
  98 }
  99
 100 static void read_fan_from_i2c(struct i2c_client *client, u16 *output,
 101                               u8 hi_addr, u8 lo_addr)
 102 {
 103         u8 high_byte, lo_byte;
 104
 105         if (read_u8_from_i2c(client, hi_addr, &high_byte) < 0)
 106                 return;
 107
 108         if (read_u8_from_i2c(client, lo_addr, &lo_byte) < 0)
 109                 return;
 110
 111         *output = ((u16)high_byte << 5) | (lo_byte >> 3);
 112 }
 113
 114 static void write_fan_target_to_i2c(struct i2c_client *client, u16 new_target)
 115 {
 116         u8 high_byte = (new_target & 0x1fe0) >> 5;
 117         u8 low_byte = (new_target & 0x001f) << 3;
 118         i2c_smbus_write_byte_data(client, REG_FAN_TARGET_LO, low_byte);
 119         i2c_smbus_write_byte_data(client, REG_FAN_TARGET_HI, high_byte);
 120 }
 121
 122 static void read_fan_config_from_i2c(struct i2c_client *client)
 123
 124 {
 125         struct emc2103_data *data = i2c_get_clientdata(client);
 126         u8 conf1;
 127
 128         if (read_u8_from_i2c(client, REG_FAN_CONF1, &conf1) < 0)
 129                 return;
 130
 131         data->fan_multiplier = 1 << ((conf1 & 0x60) >> 5);
 132         data->fan_rpm_control = (conf1 & 0x80) != 0;
 133 }
 134
 135 static struct emc2103_data *emc2103_update_device(struct device *dev)
 136 {
 137         struct emc2103_data *data = dev_get_drvdata(dev);
 138         struct i2c_client *client = data->client;
 139
 140         mutex_lock(&data->update_lock);
 141
 142         if (time_after(jiffies, data->last_updated + HZ + HZ / 2)
 143             || !data->valid) {
 144                 int i;
 145
 146                 for (i = 0; i < data->temp_count; i++) {
 147                         read_temp_from_i2c(client, REG_TEMP[i], &data->temp[i]);
 148                         read_u8_from_i2c(client, REG_TEMP_MIN[i],
 149                                 &data->temp_min[i]);
 150                         read_u8_from_i2c(client, REG_TEMP_MAX[i],
 151                                 &data->temp_max[i]);
 152                 }
 153
 154                 read_u8_from_i2c(client, REG_TEMP_MIN_ALARM,
 155                         &data->temp_min_alarm);
 156                 read_u8_from_i2c(client, REG_TEMP_MAX_ALARM,
 157                         &data->temp_max_alarm);
 158
 159                 read_fan_from_i2c(client, &data->fan_tach,
 160                         REG_FAN_TACH_HI, REG_FAN_TACH_LO);
 161                 read_fan_from_i2c(client, &data->fan_target,
 162                         REG_FAN_TARGET_HI, REG_FAN_TARGET_LO);
 163                 read_fan_config_from_i2c(client);
 164
 165                 data->last_updated = jiffies;
 166                 data->valid = true;
 167         }
 168
 169         mutex_unlock(&data->update_lock);
 170
 171         return data;
 172 }
 173
 174 static ssize_t
 175 temp_show(struct device *dev, struct device_attribute *da, char *buf)
 176 {
 177         int nr = to_sensor_dev_attr(da)->index;
 178         struct emc2103_data *data = emc2103_update_device(dev);
 179         int millidegrees = data->temp[nr].degrees * 1000
 180                 + data->temp[nr].fraction * 125;
 181         return sprintf(buf, "%d\n", millidegrees);
 182 }
 183
 184 static ssize_t
 185 temp_min_show(struct device *dev, struct device_attribute *da, char *buf)
 186 {
 187         int nr = to_sensor_dev_attr(da)->index;
 188         struct emc2103_data *data = emc2103_update_device(dev);
 189         int millidegrees = data->temp_min[nr] * 1000;
 190         return sprintf(buf, "%d\n", millidegrees);
 191 }
 192
 193 static ssize_t
 194 temp_max_show(struct device *dev, struct device_attribute *da, char *buf)
 195 {
 196         int nr = to_sensor_dev_attr(da)->index;
 197         struct emc2103_data *data = emc2103_update_device(dev);
 198         int millidegrees = data->temp_max[nr] * 1000;
 199         return sprintf(buf, "%d\n", millidegrees);
 200 }
 201
 202 static ssize_t
 203 temp_fault_show(struct device *dev, struct device_attribute *da, char *buf)
 204 {
 205         int nr = to_sensor_dev_attr(da)->index;
 206         struct emc2103_data *data = emc2103_update_device(dev);
 207         bool fault = (data->temp[nr].degrees == -128);
 208         return sprintf(buf, "%d\n", fault ? 1 : 0);
 209 }
 210
 211 static ssize_t
 212 temp_min_alarm_show(struct device *dev, struct device_attribute *da,
 213                     char *buf)
 214 {
 215         int nr = to_sensor_dev_attr(da)->index;
 216         struct emc2103_data *data = emc2103_update_device(dev);
 217         bool alarm = data->temp_min_alarm & (1 << nr);
 218         return sprintf(buf, "%d\n", alarm ? 1 : 0);
 219 }
 220
 221 static ssize_t
 222 temp_max_alarm_show(struct device *dev, struct device_attribute *da,
 223                     char *buf)
 224 {
 225         int nr = to_sensor_dev_attr(da)->index;
 226         struct emc2103_data *data = emc2103_update_device(dev);
 227         bool alarm = data->temp_max_alarm & (1 << nr);
 228         return sprintf(buf, "%d\n", alarm ? 1 : 0);
 229 }
 230
 231 static ssize_t temp_min_store(struct device *dev, struct device_attribute *da,
 232                               const char *buf, size_t count)
 233 {
 234         int nr = to_sensor_dev_attr(da)->index;
 235         struct emc2103_data *data = dev_get_drvdata(dev);
 236         struct i2c_client *client = data->client;
 237         long val;
 238
 239         int result = kstrtol(buf, 10, &val);
 240         if (result < 0)
 241                 return result;
 242
 243         val = DIV_ROUND_CLOSEST(clamp_val(val, -63000, 127000), 1000);
 244
 245         mutex_lock(&data->update_lock);
 246         data->temp_min[nr] = val;
 247         i2c_smbus_write_byte_data(client, REG_TEMP_MIN[nr], val);
 248         mutex_unlock(&data->update_lock);
 249
 250         return count;
 251 }
 252
 253 static ssize_t temp_max_store(struct device *dev, struct device_attribute *da,
 254                               const char *buf, size_t count)
 255 {
 256         int nr = to_sensor_dev_attr(da)->index;
 257         struct emc2103_data *data = dev_get_drvdata(dev);
 258         struct i2c_client *client = data->client;
 259         long val;
 260
 261         int result = kstrtol(buf, 10, &val);
 262         if (result < 0)
 263                 return result;
 264
 265         val = DIV_ROUND_CLOSEST(clamp_val(val, -63000, 127000), 1000);
 266
 267         mutex_lock(&data->update_lock);
 268         data->temp_max[nr] = val;
 269         i2c_smbus_write_byte_data(client, REG_TEMP_MAX[nr], val);
 270         mutex_unlock(&data->update_lock);
 271
 272         return count;
 273 }
 274
 275 static ssize_t
 276 fan1_input_show(struct device *dev, struct device_attribute *da, char *buf)
 277 {
 278         struct emc2103_data *data = emc2103_update_device(dev);
 279         int rpm = 0;
 280         if (data->fan_tach != 0)
 281                 rpm = (FAN_RPM_FACTOR * data->fan_multiplier) / data->fan_tach;
 282         return sprintf(buf, "%d\n", rpm);
 283 }
 284
 285 static ssize_t
 286 fan1_div_show(struct device *dev, struct device_attribute *da, char *buf)
 287 {
 288         struct emc2103_data *data = emc2103_update_device(dev);
 289         int fan_div = 8 / data->fan_multiplier;
 290         return sprintf(buf, "%d\n", fan_div);
 291 }
 292
 293 /*
 294  * Note: we also update the fan target here, because its value is
 295  * determined in part by the fan clock divider.  This follows the principle
 296  * of least surprise; the user doesn't expect the fan target to change just
 297  * because the divider changed.
 298  */
 299 static ssize_t fan1_div_store(struct device *dev, struct device_attribute *da,
 300                               const char *buf, size_t count)
 301 {
 302         struct emc2103_data *data = emc2103_update_device(dev);
 303         struct i2c_client *client = data->client;
 304         int new_range_bits, old_div = 8 / data->fan_multiplier;
 305         long new_div;
 306
 307         int status = kstrtol(buf, 10, &new_div);
 308         if (status < 0)
 309                 return status;
 310
 311         if (new_div == old_div) /* No change */
 312                 return count;
 313
 314         switch (new_div) {
 315         case 1:
 316                 new_range_bits = 3;
 317                 break;
 318         case 2:
 319                 new_range_bits = 2;
 320                 break;
 321         case 4:
 322                 new_range_bits = 1;
 323                 break;
 324         case 8:
 325                 new_range_bits = 0;
 326                 break;
 327         default:
 328                 return -EINVAL;
 329         }
 330
 331         mutex_lock(&data->update_lock);
 332
 333         status = i2c_smbus_read_byte_data(client, REG_FAN_CONF1);
 334         if (status < 0) {
 335                 dev_dbg(&client->dev, "reg 0x%02x, err %d\n",
 336                         REG_FAN_CONF1, status);
 337                 mutex_unlock(&data->update_lock);
 338                 return status;
 339         }
 340         status &= 0x9F;
 341         status |= (new_range_bits << 5);
 342         i2c_smbus_write_byte_data(client, REG_FAN_CONF1, status);
 343
 344         data->fan_multiplier = 8 / new_div;
 345
 346         /* update fan target if high byte is not disabled */
 347         if ((data->fan_target & 0x1fe0) != 0x1fe0) {
 348                 u16 new_target = (data->fan_target * old_div) / new_div;
 349                 data->fan_target = min(new_target, (u16)0x1fff);
 350                 write_fan_target_to_i2c(client, data->fan_target);
 351         }
 352
 353         /* invalidate data to force re-read from hardware */
 354         data->valid = false;
 355
 356         mutex_unlock(&data->update_lock);
 357         return count;
 358 }
 359
 360 static ssize_t
 361 fan1_target_show(struct device *dev, struct device_attribute *da, char *buf)
 362 {
 363         struct emc2103_data *data = emc2103_update_device(dev);
 364         int rpm = 0;
 365
 366         /* high byte of 0xff indicates disabled so return 0 */
 367         if ((data->fan_target != 0) && ((data->fan_target & 0x1fe0) != 0x1fe0))
 368                 rpm = (FAN_RPM_FACTOR * data->fan_multiplier)
 369                         / data->fan_target;
 370
 371         return sprintf(buf, "%d\n", rpm);
 372 }
 373
 374 static ssize_t fan1_target_store(struct device *dev,
 375                                  struct device_attribute *da, const char *buf,
 376                                  size_t count)
 377 {
 378         struct emc2103_data *data = emc2103_update_device(dev);
 379         struct i2c_client *client = data->client;
 380         unsigned long rpm_target;
 381
 382         int result = kstrtoul(buf, 10, &rpm_target);
 383         if (result < 0)
 384                 return result;
 385
 386         /* Datasheet states 16384 as maximum RPM target (table 3.2) */
 387         rpm_target = clamp_val(rpm_target, 0, 16384);
 388
 389         mutex_lock(&data->update_lock);
 390
 391         if (rpm_target == 0)
 392                 data->fan_target = 0x1fff;
 393         else
 394                 data->fan_target = clamp_val(
 395                         (FAN_RPM_FACTOR * data->fan_multiplier) / rpm_target,
 396                         0, 0x1fff);
 397
 398         write_fan_target_to_i2c(client, data->fan_target);
 399
 400         mutex_unlock(&data->update_lock);
 401         return count;
 402 }
 403
 404 static ssize_t
 405 fan1_fault_show(struct device *dev, struct device_attribute *da, char *buf)
 406 {
 407         struct emc2103_data *data = emc2103_update_device(dev);
 408         bool fault = ((data->fan_tach & 0x1fe0) == 0x1fe0);
 409         return sprintf(buf, "%d\n", fault ? 1 : 0);
 410 }
 411
 412 static ssize_t
 413 pwm1_enable_show(struct device *dev, struct device_attribute *da, char *buf)
 414 {
 415         struct emc2103_data *data = emc2103_update_device(dev);
 416         return sprintf(buf, "%d\n", data->fan_rpm_control ? 3 : 0);
 417 }
 418
 419 static ssize_t pwm1_enable_store(struct device *dev,
 420                                  struct device_attribute *da, const char *buf,
 421                                  size_t count)
 422 {
 423         struct emc2103_data *data = dev_get_drvdata(dev);
 424         struct i2c_client *client = data->client;
 425         long new_value;
 426         u8 conf_reg;
 427
 428         int result = kstrtol(buf, 10, &new_value);
 429         if (result < 0)
 430                 return result;
 431
 432         mutex_lock(&data->update_lock);
 433         switch (new_value) {
 434         case 0:
 435                 data->fan_rpm_control = false;
 436                 break;
 437         case 3:
 438                 data->fan_rpm_control = true;
 439                 break;
 440         default:
 441                 count = -EINVAL;
 442                 goto err;
 443         }
 444
 445         result = read_u8_from_i2c(client, REG_FAN_CONF1, &conf_reg);
 446         if (result) {
 447                 count = result;
 448                 goto err;
 449         }
 450
 451         if (data->fan_rpm_control)
 452                 conf_reg |= 0x80;
 453         else
 454                 conf_reg &= ~0x80;
 455
 456         i2c_smbus_write_byte_data(client, REG_FAN_CONF1, conf_reg);
 457 err:
 458         mutex_unlock(&data->update_lock);
 459         return count;
 460 }
 461
 462 static SENSOR_DEVICE_ATTR_RO(temp1_input, temp, 0);
 463 static SENSOR_DEVICE_ATTR_RW(temp1_min, temp_min, 0);
 464 static SENSOR_DEVICE_ATTR_RW(temp1_max, temp_max, 0);
 465 static SENSOR_DEVICE_ATTR_RO(temp1_fault, temp_fault, 0);
 466 static SENSOR_DEVICE_ATTR_RO(temp1_min_alarm, temp_min_alarm, 0);
 467 static SENSOR_DEVICE_ATTR_RO(temp1_max_alarm, temp_max_alarm, 0);
 468
 469 static SENSOR_DEVICE_ATTR_RO(temp2_input, temp, 1);
 470 static SENSOR_DEVICE_ATTR_RW(temp2_min, temp_min, 1);
 471 static SENSOR_DEVICE_ATTR_RW(temp2_max, temp_max, 1);
 472 static SENSOR_DEVICE_ATTR_RO(temp2_fault, temp_fault, 1);
 473 static SENSOR_DEVICE_ATTR_RO(temp2_min_alarm, temp_min_alarm, 1);
 474 static SENSOR_DEVICE_ATTR_RO(temp2_max_alarm, temp_max_alarm, 1);
 475
 476 static SENSOR_DEVICE_ATTR_RO(temp3_input, temp, 2);
 477 static SENSOR_DEVICE_ATTR_RW(temp3_min, temp_min, 2);
 478 static SENSOR_DEVICE_ATTR_RW(temp3_max, temp_max, 2);
 479 static SENSOR_DEVICE_ATTR_RO(temp3_fault, temp_fault, 2);
 480 static SENSOR_DEVICE_ATTR_RO(temp3_min_alarm, temp_min_alarm, 2);
 481 static SENSOR_DEVICE_ATTR_RO(temp3_max_alarm, temp_max_alarm, 2);
 482
 483 static SENSOR_DEVICE_ATTR_RO(temp4_input, temp, 3);
 484 static SENSOR_DEVICE_ATTR_RW(temp4_min, temp_min, 3);
 485 static SENSOR_DEVICE_ATTR_RW(temp4_max, temp_max, 3);
 486 static SENSOR_DEVICE_ATTR_RO(temp4_fault, temp_fault, 3);
 487 static SENSOR_DEVICE_ATTR_RO(temp4_min_alarm, temp_min_alarm, 3);
 488 static SENSOR_DEVICE_ATTR_RO(temp4_max_alarm, temp_max_alarm, 3);
 489
 490 static DEVICE_ATTR_RO(fan1_input);
 491 static DEVICE_ATTR_RW(fan1_div);
 492 static DEVICE_ATTR_RW(fan1_target);
 493 static DEVICE_ATTR_RO(fan1_fault);
 494
 495 static DEVICE_ATTR_RW(pwm1_enable);
 496
 497 /* sensors present on all models */
 498 static struct attribute *emc2103_attributes[] = {
 499         &sensor_dev_attr_temp1_input.dev_attr.attr,
 500         &sensor_dev_attr_temp1_min.dev_attr.attr,
 501         &sensor_dev_attr_temp1_max.dev_attr.attr,
 502         &sensor_dev_attr_temp1_fault.dev_attr.attr,
 503         &sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
 504         &sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
 505         &sensor_dev_attr_temp2_input.dev_attr.attr,
 506         &sensor_dev_attr_temp2_min.dev_attr.attr,
 507         &sensor_dev_attr_temp2_max.dev_attr.attr,
 508         &sensor_dev_attr_temp2_fault.dev_attr.attr,
 509         &sensor_dev_attr_temp2_min_alarm.dev_attr.attr,
 510         &sensor_dev_attr_temp2_max_alarm.dev_attr.attr,
 511         &dev_attr_fan1_input.attr,
 512         &dev_attr_fan1_div.attr,
 513         &dev_attr_fan1_target.attr,
 514         &dev_attr_fan1_fault.attr,
 515         &dev_attr_pwm1_enable.attr,
 516         NULL
 517 };
 518
 519 /* extra temperature sensors only present on 2103-2 and 2103-4 */
 520 static struct attribute *emc2103_attributes_temp3[] = {
 521         &sensor_dev_attr_temp3_input.dev_attr.attr,
 522         &sensor_dev_attr_temp3_min.dev_attr.attr,
 523         &sensor_dev_attr_temp3_max.dev_attr.attr,
 524         &sensor_dev_attr_temp3_fault.dev_attr.attr,
 525         &sensor_dev_attr_temp3_min_alarm.dev_attr.attr,
 526         &sensor_dev_attr_temp3_max_alarm.dev_attr.attr,
 527         NULL
 528 };
 529
 530 /* extra temperature sensors only present on 2103-2 and 2103-4 in APD mode */
 531 static struct attribute *emc2103_attributes_temp4[] = {
 532         &sensor_dev_attr_temp4_input.dev_attr.attr,
 533         &sensor_dev_attr_temp4_min.dev_attr.attr,
 534         &sensor_dev_attr_temp4_max.dev_attr.attr,
 535         &sensor_dev_attr_temp4_fault.dev_attr.attr,
 536         &sensor_dev_attr_temp4_min_alarm.dev_attr.attr,
 537         &sensor_dev_attr_temp4_max_alarm.dev_attr.attr,
 538         NULL
 539 };
 540
 541 static const struct attribute_group emc2103_group = {
 542         .attrs = emc2103_attributes,
 543 };
 544
 545 static const struct attribute_group emc2103_temp3_group = {
 546         .attrs = emc2103_attributes_temp3,
 547 };
 548
 549 static const struct attribute_group emc2103_temp4_group = {
 550         .attrs = emc2103_attributes_temp4,
 551 };
 552
 553 static int
 554 emc2103_probe(struct i2c_client *client, const struct i2c_device_id *id)
 555 {
 556         struct emc2103_data *data;
 557         struct device *hwmon_dev;
 558         int status, idx = 0;
 559
 560         if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA))
 561                 return -EIO;
 562
 563         data = devm_kzalloc(&client->dev, sizeof(struct emc2103_data),
 564                             GFP_KERNEL);
 565         if (!data)
 566                 return -ENOMEM;
 567
 568         i2c_set_clientdata(client, data);
 569         data->client = client;
 570         mutex_init(&data->update_lock);
 571
 572         /* 2103-2 and 2103-4 have 3 external diodes, 2103-1 has 1 */
 573         status = i2c_smbus_read_byte_data(client, REG_PRODUCT_ID);
 574         if (status == 0x24) {
 575                 /* 2103-1 only has 1 external diode */
 576                 data->temp_count = 2;
 577         } else {
 578                 /* 2103-2 and 2103-4 have 3 or 4 external diodes */
 579                 status = i2c_smbus_read_byte_data(client, REG_CONF1);
 580                 if (status < 0) {
 581                         dev_dbg(&client->dev, "reg 0x%02x, err %d\n", REG_CONF1,
 582                                 status);
 583                         return status;
 584                 }
 585
 586                 /* detect current state of hardware */
 587                 data->temp_count = (status & 0x01) ? 4 : 3;
 588
 589                 /* force APD state if module parameter is set */
 590                 if (apd == 0) {
 591                         /* force APD mode off */
 592                         data->temp_count = 3;
 593                         status &= ~(0x01);
 594                         i2c_smbus_write_byte_data(client, REG_CONF1, status);
 595                 } else if (apd == 1) {
 596                         /* force APD mode on */
 597                         data->temp_count = 4;
 598                         status |= 0x01;
 599                         i2c_smbus_write_byte_data(client, REG_CONF1, status);
 600                 }
 601         }
 602
 603         /* sysfs hooks */
 604         data->groups[idx++] = &emc2103_group;
 605         if (data->temp_count >= 3)
 606                 data->groups[idx++] = &emc2103_temp3_group;
 607         if (data->temp_count == 4)
 608                 data->groups[idx++] = &emc2103_temp4_group;
 609
 610         hwmon_dev = devm_hwmon_device_register_with_groups(&client->dev,
 611                                                            client->name, data,
 612                                                            data->groups);
 613         if (IS_ERR(hwmon_dev))
 614                 return PTR_ERR(hwmon_dev);
 615
 616         dev_info(&client->dev, "%s: sensor '%s'\n",
 617                  dev_name(hwmon_dev), client->name);
 618
 619         return 0;
 620 }
 621
 622 static const struct i2c_device_id emc2103_ids[] = {
 623         { "emc2103", 0, },
 624         { /* LIST END */ }
 625 };
 626 MODULE_DEVICE_TABLE(i2c, emc2103_ids);
 627
 628 /* Return 0 if detection is successful, -ENODEV otherwise */
 629 static int
 630 emc2103_detect(struct i2c_client *new_client, struct i2c_board_info *info)
 631 {
 632         struct i2c_adapter *adapter = new_client->adapter;
 633         int manufacturer, product;
 634
 635         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
 636                 return -ENODEV;
 637
 638         manufacturer = i2c_smbus_read_byte_data(new_client, REG_MFG_ID);
 639         if (manufacturer != 0x5D)
 640                 return -ENODEV;
 641
 642         product = i2c_smbus_read_byte_data(new_client, REG_PRODUCT_ID);
 643         if ((product != 0x24) && (product != 0x26))
 644                 return -ENODEV;
 645
 646         strlcpy(info->type, "emc2103", I2C_NAME_SIZE);
 647
 648         return 0;
 649 }
 650
 651 static struct i2c_driver emc2103_driver = {
 652         .class          = I2C_CLASS_HWMON,
 653         .driver = {
 654                 .name   = "emc2103",
 655         },
 656         .probe          = emc2103_probe,
 657         .id_table       = emc2103_ids,
 658         .detect         = emc2103_detect,
 659         .address_list   = normal_i2c,
 660 };
 661
 662 module_i2c_driver(emc2103_driver);
 663
 664 MODULE_AUTHOR("Steve Glendinning <steve.glendinning@shawell.net>");
 665 MODULE_DESCRIPTION("SMSC EMC2103 hwmon driver");
 666 MODULE_LICENSE("GPL");