drivers/hwmon/max6650.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * max6650.c - Part of lm_sensors, Linux kernel modules for hardware
   4  *             monitoring.
   5  *
   6  * (C) 2007 by Hans J. Koch <hjk@hansjkoch.de>
   7  *
   8  * based on code written by John Morris <john.morris@spirentcom.com>
   9  * Copyright (c) 2003 Spirent Communications
  10  * and Claus Gindhart <claus.gindhart@kontron.com>
  11  *
  12  * This module has only been tested with the MAX6650 chip. It should
  13  * also work with the MAX6651. It does not distinguish max6650 and max6651
  14  * chips.
  15  *
  16  * The datasheet was last seen at:
  17  *
  18  *        http://pdfserv.maxim-ic.com/en/ds/MAX6650-MAX6651.pdf
  19  */
  20
  21 #include <linux/module.h>
  22 #include <linux/init.h>
  23 #include <linux/slab.h>
  24 #include <linux/jiffies.h>
  25 #include <linux/i2c.h>
  26 #include <linux/hwmon.h>
  27 #include <linux/hwmon-sysfs.h>
  28 #include <linux/err.h>
  29 #include <linux/of_device.h>
  30 #include <linux/thermal.h>
  31
  32 /*
  33  * Insmod parameters
  34  */
  35
  36 /* fan_voltage: 5=5V fan, 12=12V fan, 0=don't change */
  37 static int fan_voltage;
  38 /* prescaler: Possible values are 1, 2, 4, 8, 16 or 0 for don't change */
  39 static int prescaler;
  40 /* clock: The clock frequency of the chip (max6651 can be clocked externally) */
  41 static int clock = 254000;
  42
  43 module_param(fan_voltage, int, 0444);
  44 module_param(prescaler, int, 0444);
  45 module_param(clock, int, 0444);
  46
  47 /*
  48  * MAX 6650/6651 registers
  49  */
  50
  51 #define MAX6650_REG_SPEED       0x00
  52 #define MAX6650_REG_CONFIG      0x02
  53 #define MAX6650_REG_GPIO_DEF    0x04
  54 #define MAX6650_REG_DAC         0x06
  55 #define MAX6650_REG_ALARM_EN    0x08
  56 #define MAX6650_REG_ALARM       0x0A
  57 #define MAX6650_REG_TACH0       0x0C
  58 #define MAX6650_REG_TACH1       0x0E
  59 #define MAX6650_REG_TACH2       0x10
  60 #define MAX6650_REG_TACH3       0x12
  61 #define MAX6650_REG_GPIO_STAT   0x14
  62 #define MAX6650_REG_COUNT       0x16
  63
  64 /*
  65  * Config register bits
  66  */
  67
  68 #define MAX6650_CFG_V12                 0x08
  69 #define MAX6650_CFG_PRESCALER_MASK      0x07
  70 #define MAX6650_CFG_PRESCALER_2         0x01
  71 #define MAX6650_CFG_PRESCALER_4         0x02
  72 #define MAX6650_CFG_PRESCALER_8         0x03
  73 #define MAX6650_CFG_PRESCALER_16        0x04
  74 #define MAX6650_CFG_MODE_MASK           0x30
  75 #define MAX6650_CFG_MODE_ON             0x00
  76 #define MAX6650_CFG_MODE_OFF            0x10
  77 #define MAX6650_CFG_MODE_CLOSED_LOOP    0x20
  78 #define MAX6650_CFG_MODE_OPEN_LOOP      0x30
  79 #define MAX6650_COUNT_MASK              0x03
  80
  81 /*
  82  * Alarm status register bits
  83  */
  84
  85 #define MAX6650_ALRM_MAX        0x01
  86 #define MAX6650_ALRM_MIN        0x02
  87 #define MAX6650_ALRM_TACH       0x04
  88 #define MAX6650_ALRM_GPIO1      0x08
  89 #define MAX6650_ALRM_GPIO2      0x10
  90
  91 /* Minimum and maximum values of the FAN-RPM */
  92 #define FAN_RPM_MIN 240
  93 #define FAN_RPM_MAX 30000
  94
  95 #define DIV_FROM_REG(reg) (1 << (reg & 7))
  96
  97 /*
  98  * Client data (each client gets its own)
  99  */
 100
 101 struct max6650_data {
 102         struct i2c_client *client;
 103         const struct attribute_group *groups[3];
 104         struct thermal_cooling_device *cooling_dev;
 105         struct mutex update_lock;
 106         int nr_fans;
 107         char valid; /* zero until following fields are valid */
 108         unsigned long last_updated; /* in jiffies */
 109
 110         /* register values */
 111         u8 speed;
 112         u8 config;
 113         u8 tach[4];
 114         u8 count;
 115         u8 dac;
 116         u8 alarm;
 117         unsigned long cooling_dev_state;
 118 };
 119
 120 static const u8 tach_reg[] = {
 121         MAX6650_REG_TACH0,
 122         MAX6650_REG_TACH1,
 123         MAX6650_REG_TACH2,
 124         MAX6650_REG_TACH3,
 125 };
 126
 127 static const struct of_device_id __maybe_unused max6650_dt_match[] = {
 128         {
 129                 .compatible = "maxim,max6650",
 130                 .data = (void *)1
 131         },
 132         {
 133                 .compatible = "maxim,max6651",
 134                 .data = (void *)4
 135         },
 136         { },
 137 };
 138 MODULE_DEVICE_TABLE(of, max6650_dt_match);
 139
 140 static struct max6650_data *max6650_update_device(struct device *dev)
 141 {
 142         struct max6650_data *data = dev_get_drvdata(dev);
 143         struct i2c_client *client = data->client;
 144         int i;
 145
 146         mutex_lock(&data->update_lock);
 147
 148         if (time_after(jiffies, data->last_updated + HZ) || !data->valid) {
 149                 data->speed = i2c_smbus_read_byte_data(client,
 150                                                        MAX6650_REG_SPEED);
 151                 data->config = i2c_smbus_read_byte_data(client,
 152                                                         MAX6650_REG_CONFIG);
 153                 for (i = 0; i < data->nr_fans; i++) {
 154                         data->tach[i] = i2c_smbus_read_byte_data(client,
 155                                                                  tach_reg[i]);
 156                 }
 157                 data->count = i2c_smbus_read_byte_data(client,
 158                                                         MAX6650_REG_COUNT);
 159                 data->dac = i2c_smbus_read_byte_data(client, MAX6650_REG_DAC);
 160
 161                 /*
 162                  * Alarms are cleared on read in case the condition that
 163                  * caused the alarm is removed. Keep the value latched here
 164                  * for providing the register through different alarm files.
 165                  */
 166                 data->alarm |= i2c_smbus_read_byte_data(client,
 167                                                         MAX6650_REG_ALARM);
 168
 169                 data->last_updated = jiffies;
 170                 data->valid = 1;
 171         }
 172
 173         mutex_unlock(&data->update_lock);
 174
 175         return data;
 176 }
 177
 178 /*
 179  * Change the operating mode of the chip (if needed).
 180  * mode is one of the MAX6650_CFG_MODE_* values.
 181  */
 182 static int max6650_set_operating_mode(struct max6650_data *data, u8 mode)
 183 {
 184         int result;
 185         u8 config = data->config;
 186
 187         if (mode == (config & MAX6650_CFG_MODE_MASK))
 188                 return 0;
 189
 190         config = (config & ~MAX6650_CFG_MODE_MASK) | mode;
 191
 192         result = i2c_smbus_write_byte_data(data->client, MAX6650_REG_CONFIG,
 193                                            config);
 194         if (result < 0)
 195                 return result;
 196
 197         data->config = config;
 198
 199         return 0;
 200 }
 201
 202 static ssize_t fan_show(struct device *dev, struct device_attribute *devattr,
 203                         char *buf)
 204 {
 205         struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
 206         struct max6650_data *data = max6650_update_device(dev);
 207         int rpm;
 208
 209         /*
 210          * Calculation details:
 211          *
 212          * Each tachometer counts over an interval given by the "count"
 213          * register (0.25, 0.5, 1 or 2 seconds). This module assumes
 214          * that the fans produce two pulses per revolution (this seems
 215          * to be the most common).
 216          */
 217
 218         rpm = ((data->tach[attr->index] * 120) / DIV_FROM_REG(data->count));
 219         return sprintf(buf, "%d\n", rpm);
 220 }
 221
 222 /*
 223  * Set the fan speed to the specified RPM (or read back the RPM setting).
 224  * This works in closed loop mode only. Use pwm1 for open loop speed setting.
 225  *
 226  * The MAX6650/1 will automatically control fan speed when in closed loop
 227  * mode.
 228  *
 229  * Assumptions:
 230  *
 231  * 1) The MAX6650/1 internal 254kHz clock frequency is set correctly. Use
 232  *    the clock module parameter if you need to fine tune this.
 233  *
 234  * 2) The prescaler (low three bits of the config register) has already
 235  *    been set to an appropriate value. Use the prescaler module parameter
 236  *    if your BIOS doesn't initialize the chip properly.
 237  *
 238  * The relevant equations are given on pages 21 and 22 of the datasheet.
 239  *
 240  * From the datasheet, the relevant equation when in regulation is:
 241  *
 242  *    [fCLK / (128 x (KTACH + 1))] = 2 x FanSpeed / KSCALE
 243  *
 244  * where:
 245  *
 246  *    fCLK is the oscillator frequency (either the 254kHz internal
 247  *         oscillator or the externally applied clock)
 248  *
 249  *    KTACH is the value in the speed register
 250  *
 251  *    FanSpeed is the speed of the fan in rps
 252  *
 253  *    KSCALE is the prescaler value (1, 2, 4, 8, or 16)
 254  *
 255  * When reading, we need to solve for FanSpeed. When writing, we need to
 256  * solve for KTACH.
 257  *
 258  * Note: this tachometer is completely separate from the tachometers
 259  * used to measure the fan speeds. Only one fan's speed (fan1) is
 260  * controlled.
 261  */
 262
 263 static ssize_t fan1_target_show(struct device *dev,
 264                                 struct device_attribute *devattr, char *buf)
 265 {
 266         struct max6650_data *data = max6650_update_device(dev);
 267         int kscale, ktach, rpm;
 268
 269         /*
 270          * Use the datasheet equation:
 271          *
 272          *    FanSpeed = KSCALE x fCLK / [256 x (KTACH + 1)]
 273          *
 274          * then multiply by 60 to give rpm.
 275          */
 276
 277         kscale = DIV_FROM_REG(data->config);
 278         ktach = data->speed;
 279         rpm = 60 * kscale * clock / (256 * (ktach + 1));
 280         return sprintf(buf, "%d\n", rpm);
 281 }
 282
 283 static int max6650_set_target(struct max6650_data *data, unsigned long rpm)
 284 {
 285         int kscale, ktach;
 286
 287         if (rpm == 0)
 288                 return max6650_set_operating_mode(data, MAX6650_CFG_MODE_OFF);
 289
 290         rpm = clamp_val(rpm, FAN_RPM_MIN, FAN_RPM_MAX);
 291
 292         /*
 293          * Divide the required speed by 60 to get from rpm to rps, then
 294          * use the datasheet equation:
 295          *
 296          *     KTACH = [(fCLK x KSCALE) / (256 x FanSpeed)] - 1
 297          */
 298
 299         kscale = DIV_FROM_REG(data->config);
 300         ktach = ((clock * kscale) / (256 * rpm / 60)) - 1;
 301         if (ktach < 0)
 302                 ktach = 0;
 303         if (ktach > 255)
 304                 ktach = 255;
 305         data->speed = ktach;
 306
 307         return i2c_smbus_write_byte_data(data->client, MAX6650_REG_SPEED,
 308                                          data->speed);
 309 }
 310
 311 static ssize_t fan1_target_store(struct device *dev,
 312                                  struct device_attribute *devattr,
 313                                  const char *buf, size_t count)
 314 {
 315         struct max6650_data *data = dev_get_drvdata(dev);
 316         unsigned long rpm;
 317         int err;
 318
 319         err = kstrtoul(buf, 10, &rpm);
 320         if (err)
 321                 return err;
 322
 323         mutex_lock(&data->update_lock);
 324
 325         err = max6650_set_target(data, rpm);
 326
 327         mutex_unlock(&data->update_lock);
 328
 329         if (err < 0)
 330                 return err;
 331
 332         return count;
 333 }
 334
 335 /*
 336  * Get/set the fan speed in open loop mode using pwm1 sysfs file.
 337  * Speed is given as a relative value from 0 to 255, where 255 is maximum
 338  * speed. Note that this is done by writing directly to the chip's DAC,
 339  * it won't change the closed loop speed set by fan1_target.
 340  * Also note that due to rounding errors it is possible that you don't read
 341  * back exactly the value you have set.
 342  */
 343
 344 static ssize_t pwm1_show(struct device *dev, struct device_attribute *devattr,
 345                          char *buf)
 346 {
 347         int pwm;
 348         struct max6650_data *data = max6650_update_device(dev);
 349
 350         /*
 351          * Useful range for dac is 0-180 for 12V fans and 0-76 for 5V fans.
 352          * Lower DAC values mean higher speeds.
 353          */
 354         if (data->config & MAX6650_CFG_V12)
 355                 pwm = 255 - (255 * (int)data->dac)/180;
 356         else
 357                 pwm = 255 - (255 * (int)data->dac)/76;
 358
 359         if (pwm < 0)
 360                 pwm = 0;
 361
 362         return sprintf(buf, "%d\n", pwm);
 363 }
 364
 365 static ssize_t pwm1_store(struct device *dev,
 366                           struct device_attribute *devattr, const char *buf,
 367                           size_t count)
 368 {
 369         struct max6650_data *data = dev_get_drvdata(dev);
 370         struct i2c_client *client = data->client;
 371         unsigned long pwm;
 372         int err;
 373
 374         err = kstrtoul(buf, 10, &pwm);
 375         if (err)
 376                 return err;
 377
 378         pwm = clamp_val(pwm, 0, 255);
 379
 380         mutex_lock(&data->update_lock);
 381
 382         if (data->config & MAX6650_CFG_V12)
 383                 data->dac = 180 - (180 * pwm)/255;
 384         else
 385                 data->dac = 76 - (76 * pwm)/255;
 386         err = i2c_smbus_write_byte_data(client, MAX6650_REG_DAC, data->dac);
 387
 388         mutex_unlock(&data->update_lock);
 389
 390         return err < 0 ? err : count;
 391 }
 392
 393 /*
 394  * Get/Set controller mode:
 395  * Possible values:
 396  * 0 = Fan always on
 397  * 1 = Open loop, Voltage is set according to speed, not regulated.
 398  * 2 = Closed loop, RPM for all fans regulated by fan1 tachometer
 399  * 3 = Fan off
 400  */
 401 static ssize_t pwm1_enable_show(struct device *dev,
 402                                 struct device_attribute *devattr, char *buf)
 403 {
 404         struct max6650_data *data = max6650_update_device(dev);
 405         int mode = (data->config & MAX6650_CFG_MODE_MASK) >> 4;
 406         int sysfs_modes[4] = {0, 3, 2, 1};
 407
 408         return sprintf(buf, "%d\n", sysfs_modes[mode]);
 409 }
 410
 411 static ssize_t pwm1_enable_store(struct device *dev,
 412                                  struct device_attribute *devattr,
 413                                  const char *buf, size_t count)
 414 {
 415         struct max6650_data *data = dev_get_drvdata(dev);
 416         unsigned long mode;
 417         int err;
 418         const u8 max6650_modes[] = {
 419                 MAX6650_CFG_MODE_ON,
 420                 MAX6650_CFG_MODE_OPEN_LOOP,
 421                 MAX6650_CFG_MODE_CLOSED_LOOP,
 422                 MAX6650_CFG_MODE_OFF,
 423                 };
 424
 425         err = kstrtoul(buf, 10, &mode);
 426         if (err)
 427                 return err;
 428
 429         if (mode >= ARRAY_SIZE(max6650_modes))
 430                 return -EINVAL;
 431
 432         mutex_lock(&data->update_lock);
 433
 434         max6650_set_operating_mode(data, max6650_modes[mode]);
 435
 436         mutex_unlock(&data->update_lock);
 437
 438         return count;
 439 }
 440
 441 /*
 442  * Read/write functions for fan1_div sysfs file. The MAX6650 has no such
 443  * divider. We handle this by converting between divider and counttime:
 444  *
 445  * (counttime == k) <==> (divider == 2^k), k = 0, 1, 2, or 3
 446  *
 447  * Lower values of k allow to connect a faster fan without the risk of
 448  * counter overflow. The price is lower resolution. You can also set counttime
 449  * using the module parameter. Note that the module parameter "prescaler" also
 450  * influences the behaviour. Unfortunately, there's no sysfs attribute
 451  * defined for that. See the data sheet for details.
 452  */
 453
 454 static ssize_t fan1_div_show(struct device *dev,
 455                              struct device_attribute *devattr, char *buf)
 456 {
 457         struct max6650_data *data = max6650_update_device(dev);
 458
 459         return sprintf(buf, "%d\n", DIV_FROM_REG(data->count));
 460 }
 461
 462 static ssize_t fan1_div_store(struct device *dev,
 463                               struct device_attribute *devattr,
 464                               const char *buf, size_t count)
 465 {
 466         struct max6650_data *data = dev_get_drvdata(dev);
 467         struct i2c_client *client = data->client;
 468         unsigned long div;
 469         int err;
 470
 471         err = kstrtoul(buf, 10, &div);
 472         if (err)
 473                 return err;
 474
 475         mutex_lock(&data->update_lock);
 476         switch (div) {
 477         case 1:
 478                 data->count = 0;
 479                 break;
 480         case 2:
 481                 data->count = 1;
 482                 break;
 483         case 4:
 484                 data->count = 2;
 485                 break;
 486         case 8:
 487                 data->count = 3;
 488                 break;
 489         default:
 490                 mutex_unlock(&data->update_lock);
 491                 return -EINVAL;
 492         }
 493
 494         i2c_smbus_write_byte_data(client, MAX6650_REG_COUNT, data->count);
 495         mutex_unlock(&data->update_lock);
 496
 497         return count;
 498 }
 499
 500 /*
 501  * Get alarm stati:
 502  * Possible values:
 503  * 0 = no alarm
 504  * 1 = alarm
 505  */
 506
 507 static ssize_t alarm_show(struct device *dev,
 508                           struct device_attribute *devattr, char *buf)
 509 {
 510         struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
 511         struct max6650_data *data = max6650_update_device(dev);
 512         struct i2c_client *client = data->client;
 513         int alarm = 0;
 514
 515         if (data->alarm & attr->index) {
 516                 mutex_lock(&data->update_lock);
 517                 alarm = 1;
 518                 data->alarm &= ~attr->index;
 519                 data->alarm |= i2c_smbus_read_byte_data(client,
 520                                                         MAX6650_REG_ALARM);
 521                 mutex_unlock(&data->update_lock);
 522         }
 523
 524         return sprintf(buf, "%d\n", alarm);
 525 }
 526
 527 static SENSOR_DEVICE_ATTR_RO(fan1_input, fan, 0);
 528 static SENSOR_DEVICE_ATTR_RO(fan2_input, fan, 1);
 529 static SENSOR_DEVICE_ATTR_RO(fan3_input, fan, 2);
 530 static SENSOR_DEVICE_ATTR_RO(fan4_input, fan, 3);
 531 static DEVICE_ATTR_RW(fan1_target);
 532 static DEVICE_ATTR_RW(fan1_div);
 533 static DEVICE_ATTR_RW(pwm1_enable);
 534 static DEVICE_ATTR_RW(pwm1);
 535 static SENSOR_DEVICE_ATTR_RO(fan1_max_alarm, alarm, MAX6650_ALRM_MAX);
 536 static SENSOR_DEVICE_ATTR_RO(fan1_min_alarm, alarm, MAX6650_ALRM_MIN);
 537 static SENSOR_DEVICE_ATTR_RO(fan1_fault, alarm, MAX6650_ALRM_TACH);
 538 static SENSOR_DEVICE_ATTR_RO(gpio1_alarm, alarm, MAX6650_ALRM_GPIO1);
 539 static SENSOR_DEVICE_ATTR_RO(gpio2_alarm, alarm, MAX6650_ALRM_GPIO2);
 540
 541 static umode_t max6650_attrs_visible(struct kobject *kobj, struct attribute *a,
 542                                     int n)
 543 {
 544         struct device *dev = container_of(kobj, struct device, kobj);
 545         struct max6650_data *data = dev_get_drvdata(dev);
 546         struct i2c_client *client = data->client;
 547         u8 alarm_en = i2c_smbus_read_byte_data(client, MAX6650_REG_ALARM_EN);
 548         struct device_attribute *devattr;
 549
 550         /*
 551          * Hide the alarms that have not been enabled by the firmware
 552          */
 553
 554         devattr = container_of(a, struct device_attribute, attr);
 555         if (devattr == &sensor_dev_attr_fan1_max_alarm.dev_attr
 556          || devattr == &sensor_dev_attr_fan1_min_alarm.dev_attr
 557          || devattr == &sensor_dev_attr_fan1_fault.dev_attr
 558          || devattr == &sensor_dev_attr_gpio1_alarm.dev_attr
 559          || devattr == &sensor_dev_attr_gpio2_alarm.dev_attr) {
 560                 if (!(alarm_en & to_sensor_dev_attr(devattr)->index))
 561                         return 0;
 562         }
 563
 564         return a->mode;
 565 }
 566
 567 static struct attribute *max6650_attrs[] = {
 568         &sensor_dev_attr_fan1_input.dev_attr.attr,
 569         &dev_attr_fan1_target.attr,
 570         &dev_attr_fan1_div.attr,
 571         &dev_attr_pwm1_enable.attr,
 572         &dev_attr_pwm1.attr,
 573         &sensor_dev_attr_fan1_max_alarm.dev_attr.attr,
 574         &sensor_dev_attr_fan1_min_alarm.dev_attr.attr,
 575         &sensor_dev_attr_fan1_fault.dev_attr.attr,
 576         &sensor_dev_attr_gpio1_alarm.dev_attr.attr,
 577         &sensor_dev_attr_gpio2_alarm.dev_attr.attr,
 578         NULL
 579 };
 580
 581 static const struct attribute_group max6650_group = {
 582         .attrs = max6650_attrs,
 583         .is_visible = max6650_attrs_visible,
 584 };
 585
 586 static struct attribute *max6651_attrs[] = {
 587         &sensor_dev_attr_fan2_input.dev_attr.attr,
 588         &sensor_dev_attr_fan3_input.dev_attr.attr,
 589         &sensor_dev_attr_fan4_input.dev_attr.attr,
 590         NULL
 591 };
 592
 593 static const struct attribute_group max6651_group = {
 594         .attrs = max6651_attrs,
 595 };
 596
 597 /*
 598  * Real code
 599  */
 600
 601 static int max6650_init_client(struct max6650_data *data,
 602                                struct i2c_client *client)
 603 {
 604         struct device *dev = &client->dev;
 605         int config;
 606         int err = -EIO;
 607         u32 voltage;
 608         u32 prescale;
 609         u32 target_rpm;
 610
 611         if (of_property_read_u32(dev->of_node, "maxim,fan-microvolt",
 612                                  &voltage))
 613                 voltage = fan_voltage;
 614         else
 615                 voltage /= 1000000; /* Microvolts to volts */
 616         if (of_property_read_u32(dev->of_node, "maxim,fan-prescale",
 617                                  &prescale))
 618                 prescale = prescaler;
 619
 620         config = i2c_smbus_read_byte_data(client, MAX6650_REG_CONFIG);
 621
 622         if (config < 0) {
 623                 dev_err(dev, "Error reading config, aborting.\n");
 624                 return err;
 625         }
 626
 627         switch (voltage) {
 628         case 0:
 629                 break;
 630         case 5:
 631                 config &= ~MAX6650_CFG_V12;
 632                 break;
 633         case 12:
 634                 config |= MAX6650_CFG_V12;
 635                 break;
 636         default:
 637                 dev_err(dev, "illegal value for fan_voltage (%d)\n", voltage);
 638         }
 639
 640         switch (prescale) {
 641         case 0:
 642                 break;
 643         case 1:
 644                 config &= ~MAX6650_CFG_PRESCALER_MASK;
 645                 break;
 646         case 2:
 647                 config = (config & ~MAX6650_CFG_PRESCALER_MASK)
 648                          | MAX6650_CFG_PRESCALER_2;
 649                 break;
 650         case  4:
 651                 config = (config & ~MAX6650_CFG_PRESCALER_MASK)
 652                          | MAX6650_CFG_PRESCALER_4;
 653                 break;
 654         case  8:
 655                 config = (config & ~MAX6650_CFG_PRESCALER_MASK)
 656                          | MAX6650_CFG_PRESCALER_8;
 657                 break;
 658         case 16:
 659                 config = (config & ~MAX6650_CFG_PRESCALER_MASK)
 660                          | MAX6650_CFG_PRESCALER_16;
 661                 break;
 662         default:
 663                 dev_err(dev, "illegal value for prescaler (%d)\n", prescale);
 664         }
 665
 666         dev_info(dev, "Fan voltage: %dV, prescaler: %d.\n",
 667                  (config & MAX6650_CFG_V12) ? 12 : 5,
 668                  1 << (config & MAX6650_CFG_PRESCALER_MASK));
 669
 670         if (i2c_smbus_write_byte_data(client, MAX6650_REG_CONFIG, config)) {
 671                 dev_err(dev, "Config write error, aborting.\n");
 672                 return err;
 673         }
 674
 675         data->config = config;
 676         data->count = i2c_smbus_read_byte_data(client, MAX6650_REG_COUNT);
 677
 678         if (!of_property_read_u32(client->dev.of_node, "maxim,fan-target-rpm",
 679                                   &target_rpm)) {
 680                 max6650_set_target(data, target_rpm);
 681                 max6650_set_operating_mode(data, MAX6650_CFG_MODE_CLOSED_LOOP);
 682         }
 683
 684         return 0;
 685 }
 686
 687 #if IS_ENABLED(CONFIG_THERMAL)
 688
 689 static int max6650_get_max_state(struct thermal_cooling_device *cdev,
 690                                  unsigned long *state)
 691 {
 692         *state = 255;
 693
 694         return 0;
 695 }
 696
 697 static int max6650_get_cur_state(struct thermal_cooling_device *cdev,
 698                                  unsigned long *state)
 699 {
 700         struct max6650_data *data = cdev->devdata;
 701
 702         *state = data->cooling_dev_state;
 703
 704         return 0;
 705 }
 706
 707 static int max6650_set_cur_state(struct thermal_cooling_device *cdev,
 708                                  unsigned long state)
 709 {
 710         struct max6650_data *data = cdev->devdata;
 711         struct i2c_client *client = data->client;
 712         int err;
 713
 714         state = clamp_val(state, 0, 255);
 715
 716         mutex_lock(&data->update_lock);
 717
 718         if (data->config & MAX6650_CFG_V12)
 719                 data->dac = 180 - (180 * state)/255;
 720         else
 721                 data->dac = 76 - (76 * state)/255;
 722
 723         err = i2c_smbus_write_byte_data(client, MAX6650_REG_DAC, data->dac);
 724
 725         if (!err) {
 726                 max6650_set_operating_mode(data, state ?
 727                                                    MAX6650_CFG_MODE_OPEN_LOOP :
 728                                                    MAX6650_CFG_MODE_OFF);
 729                 data->cooling_dev_state = state;
 730         }
 731
 732         mutex_unlock(&data->update_lock);
 733
 734         return err < 0 ? err : 0;
 735 }
 736
 737 static const struct thermal_cooling_device_ops max6650_cooling_ops = {
 738         .get_max_state = max6650_get_max_state,
 739         .get_cur_state = max6650_get_cur_state,
 740         .set_cur_state = max6650_set_cur_state,
 741 };
 742 #endif
 743
 744 static int max6650_probe(struct i2c_client *client,
 745                          const struct i2c_device_id *id)
 746 {
 747         struct device *dev = &client->dev;
 748         const struct of_device_id *of_id =
 749                 of_match_device(of_match_ptr(max6650_dt_match), dev);
 750         struct max6650_data *data;
 751         struct device *hwmon_dev;
 752         int err;
 753
 754         data = devm_kzalloc(dev, sizeof(struct max6650_data), GFP_KERNEL);
 755         if (!data)
 756                 return -ENOMEM;
 757
 758         data->client = client;
 759         i2c_set_clientdata(client, data);
 760         mutex_init(&data->update_lock);
 761         data->nr_fans = of_id ? (int)(uintptr_t)of_id->data : id->driver_data;
 762
 763         /*
 764          * Initialize the max6650 chip
 765          */
 766         err = max6650_init_client(data, client);
 767         if (err)
 768                 return err;
 769
 770         data->groups[0] = &max6650_group;
 771         /* 3 additional fan inputs for the MAX6651 */
 772         if (data->nr_fans == 4)
 773                 data->groups[1] = &max6651_group;
 774
 775         hwmon_dev = devm_hwmon_device_register_with_groups(dev,
 776                                                            client->name, data,
 777                                                            data->groups);
 778         err = PTR_ERR_OR_ZERO(hwmon_dev);
 779         if (err)
 780                 return err;
 781
 782 #if IS_ENABLED(CONFIG_THERMAL)
 783         data->cooling_dev =
 784                 thermal_of_cooling_device_register(client->dev.of_node,
 785                                                    client->name, data,
 786                                                    &max6650_cooling_ops);
 787         if (IS_ERR(data->cooling_dev))
 788                 dev_warn(&client->dev,
 789                          "thermal cooling device register failed: %ld\n",
 790                          PTR_ERR(data->cooling_dev));
 791 #endif
 792         return 0;
 793 }
 794
 795 static int max6650_remove(struct i2c_client *client)
 796 {
 797         struct max6650_data *data = i2c_get_clientdata(client);
 798
 799         if (!IS_ERR(data->cooling_dev))
 800                 thermal_cooling_device_unregister(data->cooling_dev);
 801
 802         return 0;
 803 }
 804
 805 static const struct i2c_device_id max6650_id[] = {
 806         { "max6650", 1 },
 807         { "max6651", 4 },
 808         { }
 809 };
 810 MODULE_DEVICE_TABLE(i2c, max6650_id);
 811
 812 static struct i2c_driver max6650_driver = {
 813         .driver = {
 814                 .name   = "max6650",
 815                 .of_match_table = of_match_ptr(max6650_dt_match),
 816         },
 817         .probe          = max6650_probe,
 818         .remove         = max6650_remove,
 819         .id_table       = max6650_id,
 820 };
 821
 822 module_i2c_driver(max6650_driver);
 823
 824 MODULE_AUTHOR("Hans J. Koch");
 825 MODULE_DESCRIPTION("MAX6650 sensor driver");
 826 MODULE_LICENSE("GPL");