drivers/hwmon/max6639.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * max6639.c - Support for Maxim MAX6639
   4  *
   5  * 2-Channel Temperature Monitor with Dual PWM Fan-Speed Controller
   6  *
   7  * Copyright (C) 2010, 2011 Roland Stigge <stigge@antcom.de>
   8  *
   9  * based on the initial MAX6639 support from semptian.net
  10  * by He Changqing <hechangqing@semptian.com>
  11  */
  12
  13 #include <linux/module.h>
  14 #include <linux/init.h>
  15 #include <linux/slab.h>
  16 #include <linux/jiffies.h>
  17 #include <linux/i2c.h>
  18 #include <linux/hwmon.h>
  19 #include <linux/hwmon-sysfs.h>
  20 #include <linux/err.h>
  21 #include <linux/mutex.h>
  22 #include <linux/platform_data/max6639.h>
  23
  24 /* Addresses to scan */
  25 static const unsigned short normal_i2c[] = { 0x2c, 0x2e, 0x2f, I2C_CLIENT_END };
  26
  27 /* The MAX6639 registers, valid channel numbers: 0, 1 */
  28 #define MAX6639_REG_TEMP(ch)                    (0x00 + (ch))
  29 #define MAX6639_REG_STATUS                      0x02
  30 #define MAX6639_REG_OUTPUT_MASK                 0x03
  31 #define MAX6639_REG_GCONFIG                     0x04
  32 #define MAX6639_REG_TEMP_EXT(ch)                (0x05 + (ch))
  33 #define MAX6639_REG_ALERT_LIMIT(ch)             (0x08 + (ch))
  34 #define MAX6639_REG_OT_LIMIT(ch)                (0x0A + (ch))
  35 #define MAX6639_REG_THERM_LIMIT(ch)             (0x0C + (ch))
  36 #define MAX6639_REG_FAN_CONFIG1(ch)             (0x10 + (ch) * 4)
  37 #define MAX6639_REG_FAN_CONFIG2a(ch)            (0x11 + (ch) * 4)
  38 #define MAX6639_REG_FAN_CONFIG2b(ch)            (0x12 + (ch) * 4)
  39 #define MAX6639_REG_FAN_CONFIG3(ch)             (0x13 + (ch) * 4)
  40 #define MAX6639_REG_FAN_CNT(ch)                 (0x20 + (ch))
  41 #define MAX6639_REG_TARGET_CNT(ch)              (0x22 + (ch))
  42 #define MAX6639_REG_FAN_PPR(ch)                 (0x24 + (ch))
  43 #define MAX6639_REG_TARGTDUTY(ch)               (0x26 + (ch))
  44 #define MAX6639_REG_FAN_START_TEMP(ch)          (0x28 + (ch))
  45 #define MAX6639_REG_DEVID                       0x3D
  46 #define MAX6639_REG_MANUID                      0x3E
  47 #define MAX6639_REG_DEVREV                      0x3F
  48
  49 /* Register bits */
  50 #define MAX6639_GCONFIG_STANDBY                 0x80
  51 #define MAX6639_GCONFIG_POR                     0x40
  52 #define MAX6639_GCONFIG_DISABLE_TIMEOUT         0x20
  53 #define MAX6639_GCONFIG_CH2_LOCAL               0x10
  54 #define MAX6639_GCONFIG_PWM_FREQ_HI             0x08
  55
  56 #define MAX6639_FAN_CONFIG1_PWM                 0x80
  57
  58 #define MAX6639_FAN_CONFIG3_THERM_FULL_SPEED    0x40
  59
  60 static const int rpm_ranges[] = { 2000, 4000, 8000, 16000 };
  61
  62 #define FAN_FROM_REG(val, rpm_range)    ((val) == 0 || (val) == 255 ? \
  63                                 0 : (rpm_ranges[rpm_range] * 30) / (val))
  64 #define TEMP_LIMIT_TO_REG(val)  clamp_val((val) / 1000, 0, 255)
  65
  66 /*
  67  * Client data (each client gets its own)
  68  */
  69 struct max6639_data {
  70         struct i2c_client *client;
  71         struct mutex update_lock;
  72         char valid;             /* !=0 if following fields are valid */
  73         unsigned long last_updated;     /* In jiffies */
  74
  75         /* Register values sampled regularly */
  76         u16 temp[2];            /* Temperature, in 1/8 C, 0..255 C */
  77         bool temp_fault[2];     /* Detected temperature diode failure */
  78         u8 fan[2];              /* Register value: TACH count for fans >=30 */
  79         u8 status;              /* Detected channel alarms and fan failures */
  80
  81         /* Register values only written to */
  82         u8 pwm[2];              /* Register value: Duty cycle 0..120 */
  83         u8 temp_therm[2];       /* THERM Temperature, 0..255 C (->_max) */
  84         u8 temp_alert[2];       /* ALERT Temperature, 0..255 C (->_crit) */
  85         u8 temp_ot[2];          /* OT Temperature, 0..255 C (->_emergency) */
  86
  87         /* Register values initialized only once */
  88         u8 ppr;                 /* Pulses per rotation 0..3 for 1..4 ppr */
  89         u8 rpm_range;           /* Index in above rpm_ranges table */
  90 };
  91
  92 static struct max6639_data *max6639_update_device(struct device *dev)
  93 {
  94         struct max6639_data *data = dev_get_drvdata(dev);
  95         struct i2c_client *client = data->client;
  96         struct max6639_data *ret = data;
  97         int i;
  98         int status_reg;
  99
 100         mutex_lock(&data->update_lock);
 101
 102         if (time_after(jiffies, data->last_updated + 2 * HZ) || !data->valid) {
 103                 int res;
 104
 105                 dev_dbg(&client->dev, "Starting max6639 update\n");
 106
 107                 status_reg = i2c_smbus_read_byte_data(client,
 108                                                       MAX6639_REG_STATUS);
 109                 if (status_reg < 0) {
 110                         ret = ERR_PTR(status_reg);
 111                         goto abort;
 112                 }
 113
 114                 data->status = status_reg;
 115
 116                 for (i = 0; i < 2; i++) {
 117                         res = i2c_smbus_read_byte_data(client,
 118                                         MAX6639_REG_FAN_CNT(i));
 119                         if (res < 0) {
 120                                 ret = ERR_PTR(res);
 121                                 goto abort;
 122                         }
 123                         data->fan[i] = res;
 124
 125                         res = i2c_smbus_read_byte_data(client,
 126                                         MAX6639_REG_TEMP_EXT(i));
 127                         if (res < 0) {
 128                                 ret = ERR_PTR(res);
 129                                 goto abort;
 130                         }
 131                         data->temp[i] = res >> 5;
 132                         data->temp_fault[i] = res & 0x01;
 133
 134                         res = i2c_smbus_read_byte_data(client,
 135                                         MAX6639_REG_TEMP(i));
 136                         if (res < 0) {
 137                                 ret = ERR_PTR(res);
 138                                 goto abort;
 139                         }
 140                         data->temp[i] |= res << 3;
 141                 }
 142
 143                 data->last_updated = jiffies;
 144                 data->valid = 1;
 145         }
 146 abort:
 147         mutex_unlock(&data->update_lock);
 148
 149         return ret;
 150 }
 151
 152 static ssize_t temp_input_show(struct device *dev,
 153                                struct device_attribute *dev_attr, char *buf)
 154 {
 155         long temp;
 156         struct max6639_data *data = max6639_update_device(dev);
 157         struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr);
 158
 159         if (IS_ERR(data))
 160                 return PTR_ERR(data);
 161
 162         temp = data->temp[attr->index] * 125;
 163         return sprintf(buf, "%ld\n", temp);
 164 }
 165
 166 static ssize_t temp_fault_show(struct device *dev,
 167                                struct device_attribute *dev_attr, char *buf)
 168 {
 169         struct max6639_data *data = max6639_update_device(dev);
 170         struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr);
 171
 172         if (IS_ERR(data))
 173                 return PTR_ERR(data);
 174
 175         return sprintf(buf, "%d\n", data->temp_fault[attr->index]);
 176 }
 177
 178 static ssize_t temp_max_show(struct device *dev,
 179                              struct device_attribute *dev_attr, char *buf)
 180 {
 181         struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr);
 182         struct max6639_data *data = dev_get_drvdata(dev);
 183
 184         return sprintf(buf, "%d\n", (data->temp_therm[attr->index] * 1000));
 185 }
 186
 187 static ssize_t temp_max_store(struct device *dev,
 188                               struct device_attribute *dev_attr,
 189                               const char *buf, size_t count)
 190 {
 191         struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr);
 192         struct max6639_data *data = dev_get_drvdata(dev);
 193         struct i2c_client *client = data->client;
 194         unsigned long val;
 195         int res;
 196
 197         res = kstrtoul(buf, 10, &val);
 198         if (res)
 199                 return res;
 200
 201         mutex_lock(&data->update_lock);
 202         data->temp_therm[attr->index] = TEMP_LIMIT_TO_REG(val);
 203         i2c_smbus_write_byte_data(client,
 204                                   MAX6639_REG_THERM_LIMIT(attr->index),
 205                                   data->temp_therm[attr->index]);
 206         mutex_unlock(&data->update_lock);
 207         return count;
 208 }
 209
 210 static ssize_t temp_crit_show(struct device *dev,
 211                               struct device_attribute *dev_attr, char *buf)
 212 {
 213         struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr);
 214         struct max6639_data *data = dev_get_drvdata(dev);
 215
 216         return sprintf(buf, "%d\n", (data->temp_alert[attr->index] * 1000));
 217 }
 218
 219 static ssize_t temp_crit_store(struct device *dev,
 220                                struct device_attribute *dev_attr,
 221                                const char *buf, size_t count)
 222 {
 223         struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr);
 224         struct max6639_data *data = dev_get_drvdata(dev);
 225         struct i2c_client *client = data->client;
 226         unsigned long val;
 227         int res;
 228
 229         res = kstrtoul(buf, 10, &val);
 230         if (res)
 231                 return res;
 232
 233         mutex_lock(&data->update_lock);
 234         data->temp_alert[attr->index] = TEMP_LIMIT_TO_REG(val);
 235         i2c_smbus_write_byte_data(client,
 236                                   MAX6639_REG_ALERT_LIMIT(attr->index),
 237                                   data->temp_alert[attr->index]);
 238         mutex_unlock(&data->update_lock);
 239         return count;
 240 }
 241
 242 static ssize_t temp_emergency_show(struct device *dev,
 243                                    struct device_attribute *dev_attr,
 244                                    char *buf)
 245 {
 246         struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr);
 247         struct max6639_data *data = dev_get_drvdata(dev);
 248
 249         return sprintf(buf, "%d\n", (data->temp_ot[attr->index] * 1000));
 250 }
 251
 252 static ssize_t temp_emergency_store(struct device *dev,
 253                                     struct device_attribute *dev_attr,
 254                                     const char *buf, size_t count)
 255 {
 256         struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr);
 257         struct max6639_data *data = dev_get_drvdata(dev);
 258         struct i2c_client *client = data->client;
 259         unsigned long val;
 260         int res;
 261
 262         res = kstrtoul(buf, 10, &val);
 263         if (res)
 264                 return res;
 265
 266         mutex_lock(&data->update_lock);
 267         data->temp_ot[attr->index] = TEMP_LIMIT_TO_REG(val);
 268         i2c_smbus_write_byte_data(client,
 269                                   MAX6639_REG_OT_LIMIT(attr->index),
 270                                   data->temp_ot[attr->index]);
 271         mutex_unlock(&data->update_lock);
 272         return count;
 273 }
 274
 275 static ssize_t pwm_show(struct device *dev, struct device_attribute *dev_attr,
 276                         char *buf)
 277 {
 278         struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr);
 279         struct max6639_data *data = dev_get_drvdata(dev);
 280
 281         return sprintf(buf, "%d\n", data->pwm[attr->index] * 255 / 120);
 282 }
 283
 284 static ssize_t pwm_store(struct device *dev,
 285                          struct device_attribute *dev_attr, const char *buf,
 286                          size_t count)
 287 {
 288         struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr);
 289         struct max6639_data *data = dev_get_drvdata(dev);
 290         struct i2c_client *client = data->client;
 291         unsigned long val;
 292         int res;
 293
 294         res = kstrtoul(buf, 10, &val);
 295         if (res)
 296                 return res;
 297
 298         val = clamp_val(val, 0, 255);
 299
 300         mutex_lock(&data->update_lock);
 301         data->pwm[attr->index] = (u8)(val * 120 / 255);
 302         i2c_smbus_write_byte_data(client,
 303                                   MAX6639_REG_TARGTDUTY(attr->index),
 304                                   data->pwm[attr->index]);
 305         mutex_unlock(&data->update_lock);
 306         return count;
 307 }
 308
 309 static ssize_t fan_input_show(struct device *dev,
 310                               struct device_attribute *dev_attr, char *buf)
 311 {
 312         struct max6639_data *data = max6639_update_device(dev);
 313         struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr);
 314
 315         if (IS_ERR(data))
 316                 return PTR_ERR(data);
 317
 318         return sprintf(buf, "%d\n", FAN_FROM_REG(data->fan[attr->index],
 319                        data->rpm_range));
 320 }
 321
 322 static ssize_t alarm_show(struct device *dev,
 323                           struct device_attribute *dev_attr, char *buf)
 324 {
 325         struct max6639_data *data = max6639_update_device(dev);
 326         struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr);
 327
 328         if (IS_ERR(data))
 329                 return PTR_ERR(data);
 330
 331         return sprintf(buf, "%d\n", !!(data->status & (1 << attr->index)));
 332 }
 333
 334 static SENSOR_DEVICE_ATTR_RO(temp1_input, temp_input, 0);
 335 static SENSOR_DEVICE_ATTR_RO(temp2_input, temp_input, 1);
 336 static SENSOR_DEVICE_ATTR_RO(temp1_fault, temp_fault, 0);
 337 static SENSOR_DEVICE_ATTR_RO(temp2_fault, temp_fault, 1);
 338 static SENSOR_DEVICE_ATTR_RW(temp1_max, temp_max, 0);
 339 static SENSOR_DEVICE_ATTR_RW(temp2_max, temp_max, 1);
 340 static SENSOR_DEVICE_ATTR_RW(temp1_crit, temp_crit, 0);
 341 static SENSOR_DEVICE_ATTR_RW(temp2_crit, temp_crit, 1);
 342 static SENSOR_DEVICE_ATTR_RW(temp1_emergency, temp_emergency, 0);
 343 static SENSOR_DEVICE_ATTR_RW(temp2_emergency, temp_emergency, 1);
 344 static SENSOR_DEVICE_ATTR_RW(pwm1, pwm, 0);
 345 static SENSOR_DEVICE_ATTR_RW(pwm2, pwm, 1);
 346 static SENSOR_DEVICE_ATTR_RO(fan1_input, fan_input, 0);
 347 static SENSOR_DEVICE_ATTR_RO(fan2_input, fan_input, 1);
 348 static SENSOR_DEVICE_ATTR_RO(fan1_fault, alarm, 1);
 349 static SENSOR_DEVICE_ATTR_RO(fan2_fault, alarm, 0);
 350 static SENSOR_DEVICE_ATTR_RO(temp1_max_alarm, alarm, 3);
 351 static SENSOR_DEVICE_ATTR_RO(temp2_max_alarm, alarm, 2);
 352 static SENSOR_DEVICE_ATTR_RO(temp1_crit_alarm, alarm, 7);
 353 static SENSOR_DEVICE_ATTR_RO(temp2_crit_alarm, alarm, 6);
 354 static SENSOR_DEVICE_ATTR_RO(temp1_emergency_alarm, alarm, 5);
 355 static SENSOR_DEVICE_ATTR_RO(temp2_emergency_alarm, alarm, 4);
 356
 357
 358 static struct attribute *max6639_attrs[] = {
 359         &sensor_dev_attr_temp1_input.dev_attr.attr,
 360         &sensor_dev_attr_temp2_input.dev_attr.attr,
 361         &sensor_dev_attr_temp1_fault.dev_attr.attr,
 362         &sensor_dev_attr_temp2_fault.dev_attr.attr,
 363         &sensor_dev_attr_temp1_max.dev_attr.attr,
 364         &sensor_dev_attr_temp2_max.dev_attr.attr,
 365         &sensor_dev_attr_temp1_crit.dev_attr.attr,
 366         &sensor_dev_attr_temp2_crit.dev_attr.attr,
 367         &sensor_dev_attr_temp1_emergency.dev_attr.attr,
 368         &sensor_dev_attr_temp2_emergency.dev_attr.attr,
 369         &sensor_dev_attr_pwm1.dev_attr.attr,
 370         &sensor_dev_attr_pwm2.dev_attr.attr,
 371         &sensor_dev_attr_fan1_input.dev_attr.attr,
 372         &sensor_dev_attr_fan2_input.dev_attr.attr,
 373         &sensor_dev_attr_fan1_fault.dev_attr.attr,
 374         &sensor_dev_attr_fan2_fault.dev_attr.attr,
 375         &sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
 376         &sensor_dev_attr_temp2_max_alarm.dev_attr.attr,
 377         &sensor_dev_attr_temp1_crit_alarm.dev_attr.attr,
 378         &sensor_dev_attr_temp2_crit_alarm.dev_attr.attr,
 379         &sensor_dev_attr_temp1_emergency_alarm.dev_attr.attr,
 380         &sensor_dev_attr_temp2_emergency_alarm.dev_attr.attr,
 381         NULL
 382 };
 383 ATTRIBUTE_GROUPS(max6639);
 384
 385 /*
 386  *  returns respective index in rpm_ranges table
 387  *  1 by default on invalid range
 388  */
 389 static int rpm_range_to_reg(int range)
 390 {
 391         int i;
 392
 393         for (i = 0; i < ARRAY_SIZE(rpm_ranges); i++) {
 394                 if (rpm_ranges[i] == range)
 395                         return i;
 396         }
 397
 398         return 1; /* default: 4000 RPM */
 399 }
 400
 401 static int max6639_init_client(struct i2c_client *client,
 402                                struct max6639_data *data)
 403 {
 404         struct max6639_platform_data *max6639_info =
 405                 dev_get_platdata(&client->dev);
 406         int i;
 407         int rpm_range = 1; /* default: 4000 RPM */
 408         int err;
 409
 410         /* Reset chip to default values, see below for GCONFIG setup */
 411         err = i2c_smbus_write_byte_data(client, MAX6639_REG_GCONFIG,
 412                                   MAX6639_GCONFIG_POR);
 413         if (err)
 414                 goto exit;
 415
 416         /* Fans pulse per revolution is 2 by default */
 417         if (max6639_info && max6639_info->ppr > 0 &&
 418                         max6639_info->ppr < 5)
 419                 data->ppr = max6639_info->ppr;
 420         else
 421                 data->ppr = 2;
 422         data->ppr -= 1;
 423
 424         if (max6639_info)
 425                 rpm_range = rpm_range_to_reg(max6639_info->rpm_range);
 426         data->rpm_range = rpm_range;
 427
 428         for (i = 0; i < 2; i++) {
 429
 430                 /* Set Fan pulse per revolution */
 431                 err = i2c_smbus_write_byte_data(client,
 432                                 MAX6639_REG_FAN_PPR(i),
 433                                 data->ppr << 6);
 434                 if (err)
 435                         goto exit;
 436
 437                 /* Fans config PWM, RPM */
 438                 err = i2c_smbus_write_byte_data(client,
 439                         MAX6639_REG_FAN_CONFIG1(i),
 440                         MAX6639_FAN_CONFIG1_PWM | rpm_range);
 441                 if (err)
 442                         goto exit;
 443
 444                 /* Fans PWM polarity high by default */
 445                 if (max6639_info && max6639_info->pwm_polarity == 0)
 446                         err = i2c_smbus_write_byte_data(client,
 447                                 MAX6639_REG_FAN_CONFIG2a(i), 0x00);
 448                 else
 449                         err = i2c_smbus_write_byte_data(client,
 450                                 MAX6639_REG_FAN_CONFIG2a(i), 0x02);
 451                 if (err)
 452                         goto exit;
 453
 454                 /*
 455                  * /THERM full speed enable,
 456                  * PWM frequency 25kHz, see also GCONFIG below
 457                  */
 458                 err = i2c_smbus_write_byte_data(client,
 459                         MAX6639_REG_FAN_CONFIG3(i),
 460                         MAX6639_FAN_CONFIG3_THERM_FULL_SPEED | 0x03);
 461                 if (err)
 462                         goto exit;
 463
 464                 /* Max. temp. 80C/90C/100C */
 465                 data->temp_therm[i] = 80;
 466                 data->temp_alert[i] = 90;
 467                 data->temp_ot[i] = 100;
 468                 err = i2c_smbus_write_byte_data(client,
 469                                 MAX6639_REG_THERM_LIMIT(i),
 470                                 data->temp_therm[i]);
 471                 if (err)
 472                         goto exit;
 473                 err = i2c_smbus_write_byte_data(client,
 474                                 MAX6639_REG_ALERT_LIMIT(i),
 475                                 data->temp_alert[i]);
 476                 if (err)
 477                         goto exit;
 478                 err = i2c_smbus_write_byte_data(client,
 479                                 MAX6639_REG_OT_LIMIT(i), data->temp_ot[i]);
 480                 if (err)
 481                         goto exit;
 482
 483                 /* PWM 120/120 (i.e. 100%) */
 484                 data->pwm[i] = 120;
 485                 err = i2c_smbus_write_byte_data(client,
 486                                 MAX6639_REG_TARGTDUTY(i), data->pwm[i]);
 487                 if (err)
 488                         goto exit;
 489         }
 490         /* Start monitoring */
 491         err = i2c_smbus_write_byte_data(client, MAX6639_REG_GCONFIG,
 492                 MAX6639_GCONFIG_DISABLE_TIMEOUT | MAX6639_GCONFIG_CH2_LOCAL |
 493                 MAX6639_GCONFIG_PWM_FREQ_HI);
 494 exit:
 495         return err;
 496 }
 497
 498 /* Return 0 if detection is successful, -ENODEV otherwise */
 499 static int max6639_detect(struct i2c_client *client,
 500                           struct i2c_board_info *info)
 501 {
 502         struct i2c_adapter *adapter = client->adapter;
 503         int dev_id, manu_id;
 504
 505         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
 506                 return -ENODEV;
 507
 508         /* Actual detection via device and manufacturer ID */
 509         dev_id = i2c_smbus_read_byte_data(client, MAX6639_REG_DEVID);
 510         manu_id = i2c_smbus_read_byte_data(client, MAX6639_REG_MANUID);
 511         if (dev_id != 0x58 || manu_id != 0x4D)
 512                 return -ENODEV;
 513
 514         strlcpy(info->type, "max6639", I2C_NAME_SIZE);
 515
 516         return 0;
 517 }
 518
 519 static int max6639_probe(struct i2c_client *client,
 520                          const struct i2c_device_id *id)
 521 {
 522         struct device *dev = &client->dev;
 523         struct max6639_data *data;
 524         struct device *hwmon_dev;
 525         int err;
 526
 527         data = devm_kzalloc(dev, sizeof(struct max6639_data), GFP_KERNEL);
 528         if (!data)
 529                 return -ENOMEM;
 530
 531         data->client = client;
 532         mutex_init(&data->update_lock);
 533
 534         /* Initialize the max6639 chip */
 535         err = max6639_init_client(client, data);
 536         if (err < 0)
 537                 return err;
 538
 539         hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
 540                                                            data,
 541                                                            max6639_groups);
 542         return PTR_ERR_OR_ZERO(hwmon_dev);
 543 }
 544
 545 #ifdef CONFIG_PM_SLEEP
 546 static int max6639_suspend(struct device *dev)
 547 {
 548         struct i2c_client *client = to_i2c_client(dev);
 549         int data = i2c_smbus_read_byte_data(client, MAX6639_REG_GCONFIG);
 550         if (data < 0)
 551                 return data;
 552
 553         return i2c_smbus_write_byte_data(client,
 554                         MAX6639_REG_GCONFIG, data | MAX6639_GCONFIG_STANDBY);
 555 }
 556
 557 static int max6639_resume(struct device *dev)
 558 {
 559         struct i2c_client *client = to_i2c_client(dev);
 560         int data = i2c_smbus_read_byte_data(client, MAX6639_REG_GCONFIG);
 561         if (data < 0)
 562                 return data;
 563
 564         return i2c_smbus_write_byte_data(client,
 565                         MAX6639_REG_GCONFIG, data & ~MAX6639_GCONFIG_STANDBY);
 566 }
 567 #endif /* CONFIG_PM_SLEEP */
 568
 569 static const struct i2c_device_id max6639_id[] = {
 570         {"max6639", 0},
 571         { }
 572 };
 573
 574 MODULE_DEVICE_TABLE(i2c, max6639_id);
 575
 576 static SIMPLE_DEV_PM_OPS(max6639_pm_ops, max6639_suspend, max6639_resume);
 577
 578 static struct i2c_driver max6639_driver = {
 579         .class = I2C_CLASS_HWMON,
 580         .driver = {
 581                    .name = "max6639",
 582                    .pm = &max6639_pm_ops,
 583                    },
 584         .probe = max6639_probe,
 585         .id_table = max6639_id,
 586         .detect = max6639_detect,
 587         .address_list = normal_i2c,
 588 };
 589
 590 module_i2c_driver(max6639_driver);
 591
 592 MODULE_AUTHOR("Roland Stigge <stigge@antcom.de>");
 593 MODULE_DESCRIPTION("max6639 driver");
 594 MODULE_LICENSE("GPL");