drivers/hwmon/gpio-fan.c

   1 /*
   2  * gpio-fan.c - Hwmon driver for fans connected to GPIO lines.
   3  *
   4  * Copyright (C) 2010 LaCie
   5  *
   6  * Author: Simon Guinot <sguinot@lacie.com>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  21  */
  22
  23 #include <linux/module.h>
  24 #include <linux/init.h>
  25 #include <linux/slab.h>
  26 #include <linux/interrupt.h>
  27 #include <linux/irq.h>
  28 #include <linux/platform_device.h>
  29 #include <linux/err.h>
  30 #include <linux/mutex.h>
  31 #include <linux/hwmon.h>
  32 #include <linux/gpio.h>
  33 #include <linux/gpio-fan.h>
  34 #include <linux/of.h>
  35 #include <linux/of_platform.h>
  36 #include <linux/of_gpio.h>
  37 #include <linux/thermal.h>
  38
  39 struct gpio_fan_data {
  40         struct platform_device  *pdev;
  41         struct device           *hwmon_dev;
  42         /* Cooling device if any */
  43         struct thermal_cooling_device *cdev;
  44         struct mutex            lock; /* lock GPIOs operations. */
  45         int                     num_ctrl;
  46         unsigned                *ctrl;
  47         int                     num_speed;
  48         struct gpio_fan_speed   *speed;
  49         int                     speed_index;
  50 #ifdef CONFIG_PM_SLEEP
  51         int                     resume_speed;
  52 #endif
  53         bool                    pwm_enable;
  54         struct gpio_fan_alarm   *alarm;
  55         struct work_struct      alarm_work;
  56 };
  57
  58 /*
  59  * Alarm GPIO.
  60  */
  61
  62 static void fan_alarm_notify(struct work_struct *ws)
  63 {
  64         struct gpio_fan_data *fan_data =
  65                 container_of(ws, struct gpio_fan_data, alarm_work);
  66
  67         sysfs_notify(&fan_data->pdev->dev.kobj, NULL, "fan1_alarm");
  68         kobject_uevent(&fan_data->pdev->dev.kobj, KOBJ_CHANGE);
  69 }
  70
  71 static irqreturn_t fan_alarm_irq_handler(int irq, void *dev_id)
  72 {
  73         struct gpio_fan_data *fan_data = dev_id;
  74
  75         schedule_work(&fan_data->alarm_work);
  76
  77         return IRQ_NONE;
  78 }
  79
  80 static ssize_t fan1_alarm_show(struct device *dev,
  81                                struct device_attribute *attr, char *buf)
  82 {
  83         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
  84         struct gpio_fan_alarm *alarm = fan_data->alarm;
  85         int value = gpio_get_value_cansleep(alarm->gpio);
  86
  87         if (alarm->active_low)
  88                 value = !value;
  89
  90         return sprintf(buf, "%d\n", value);
  91 }
  92
  93 static DEVICE_ATTR_RO(fan1_alarm);
  94
  95 static int fan_alarm_init(struct gpio_fan_data *fan_data,
  96                           struct gpio_fan_alarm *alarm)
  97 {
  98         int err;
  99         int alarm_irq;
 100         struct platform_device *pdev = fan_data->pdev;
 101
 102         fan_data->alarm = alarm;
 103
 104         err = devm_gpio_request(&pdev->dev, alarm->gpio, "GPIO fan alarm");
 105         if (err)
 106                 return err;
 107
 108         err = gpio_direction_input(alarm->gpio);
 109         if (err)
 110                 return err;
 111
 112         /*
 113          * If the alarm GPIO don't support interrupts, just leave
 114          * without initializing the fail notification support.
 115          */
 116         alarm_irq = gpio_to_irq(alarm->gpio);
 117         if (alarm_irq < 0)
 118                 return 0;
 119
 120         INIT_WORK(&fan_data->alarm_work, fan_alarm_notify);
 121         irq_set_irq_type(alarm_irq, IRQ_TYPE_EDGE_BOTH);
 122         err = devm_request_irq(&pdev->dev, alarm_irq, fan_alarm_irq_handler,
 123                                IRQF_SHARED, "GPIO fan alarm", fan_data);
 124         return err;
 125 }
 126
 127 /*
 128  * Control GPIOs.
 129  */
 130
 131 /* Must be called with fan_data->lock held, except during initialization. */
 132 static void __set_fan_ctrl(struct gpio_fan_data *fan_data, int ctrl_val)
 133 {
 134         int i;
 135
 136         for (i = 0; i < fan_data->num_ctrl; i++)
 137                 gpio_set_value_cansleep(fan_data->ctrl[i], (ctrl_val >> i) & 1);
 138 }
 139
 140 static int __get_fan_ctrl(struct gpio_fan_data *fan_data)
 141 {
 142         int i;
 143         int ctrl_val = 0;
 144
 145         for (i = 0; i < fan_data->num_ctrl; i++) {
 146                 int value;
 147
 148                 value = gpio_get_value_cansleep(fan_data->ctrl[i]);
 149                 ctrl_val |= (value << i);
 150         }
 151         return ctrl_val;
 152 }
 153
 154 /* Must be called with fan_data->lock held, except during initialization. */
 155 static void set_fan_speed(struct gpio_fan_data *fan_data, int speed_index)
 156 {
 157         if (fan_data->speed_index == speed_index)
 158                 return;
 159
 160         __set_fan_ctrl(fan_data, fan_data->speed[speed_index].ctrl_val);
 161         fan_data->speed_index = speed_index;
 162 }
 163
 164 static int get_fan_speed_index(struct gpio_fan_data *fan_data)
 165 {
 166         int ctrl_val = __get_fan_ctrl(fan_data);
 167         int i;
 168
 169         for (i = 0; i < fan_data->num_speed; i++)
 170                 if (fan_data->speed[i].ctrl_val == ctrl_val)
 171                         return i;
 172
 173         dev_warn(&fan_data->pdev->dev,
 174                  "missing speed array entry for GPIO value 0x%x\n", ctrl_val);
 175
 176         return -ENODEV;
 177 }
 178
 179 static int rpm_to_speed_index(struct gpio_fan_data *fan_data, unsigned long rpm)
 180 {
 181         struct gpio_fan_speed *speed = fan_data->speed;
 182         int i;
 183
 184         for (i = 0; i < fan_data->num_speed; i++)
 185                 if (speed[i].rpm >= rpm)
 186                         return i;
 187
 188         return fan_data->num_speed - 1;
 189 }
 190
 191 static ssize_t pwm1_show(struct device *dev, struct device_attribute *attr,
 192                          char *buf)
 193 {
 194         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 195         u8 pwm = fan_data->speed_index * 255 / (fan_data->num_speed - 1);
 196
 197         return sprintf(buf, "%d\n", pwm);
 198 }
 199
 200 static ssize_t pwm1_store(struct device *dev, struct device_attribute *attr,
 201                           const char *buf, size_t count)
 202 {
 203         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 204         unsigned long pwm;
 205         int speed_index;
 206         int ret = count;
 207
 208         if (kstrtoul(buf, 10, &pwm) || pwm > 255)
 209                 return -EINVAL;
 210
 211         mutex_lock(&fan_data->lock);
 212
 213         if (!fan_data->pwm_enable) {
 214                 ret = -EPERM;
 215                 goto exit_unlock;
 216         }
 217
 218         speed_index = DIV_ROUND_UP(pwm * (fan_data->num_speed - 1), 255);
 219         set_fan_speed(fan_data, speed_index);
 220
 221 exit_unlock:
 222         mutex_unlock(&fan_data->lock);
 223
 224         return ret;
 225 }
 226
 227 static ssize_t pwm1_enable_show(struct device *dev,
 228                                 struct device_attribute *attr, char *buf)
 229 {
 230         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 231
 232         return sprintf(buf, "%d\n", fan_data->pwm_enable);
 233 }
 234
 235 static ssize_t pwm1_enable_store(struct device *dev,
 236                                  struct device_attribute *attr,
 237                                  const char *buf, size_t count)
 238 {
 239         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 240         unsigned long val;
 241
 242         if (kstrtoul(buf, 10, &val) || val > 1)
 243                 return -EINVAL;
 244
 245         if (fan_data->pwm_enable == val)
 246                 return count;
 247
 248         mutex_lock(&fan_data->lock);
 249
 250         fan_data->pwm_enable = val;
 251
 252         /* Disable manual control mode: set fan at full speed. */
 253         if (val == 0)
 254                 set_fan_speed(fan_data, fan_data->num_speed - 1);
 255
 256         mutex_unlock(&fan_data->lock);
 257
 258         return count;
 259 }
 260
 261 static ssize_t pwm1_mode_show(struct device *dev,
 262                               struct device_attribute *attr, char *buf)
 263 {
 264         return sprintf(buf, "0\n");
 265 }
 266
 267 static ssize_t fan1_min_show(struct device *dev,
 268                              struct device_attribute *attr, char *buf)
 269 {
 270         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 271
 272         return sprintf(buf, "%d\n", fan_data->speed[0].rpm);
 273 }
 274
 275 static ssize_t fan1_max_show(struct device *dev,
 276                              struct device_attribute *attr, char *buf)
 277 {
 278         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 279
 280         return sprintf(buf, "%d\n",
 281                        fan_data->speed[fan_data->num_speed - 1].rpm);
 282 }
 283
 284 static ssize_t fan1_input_show(struct device *dev,
 285                                struct device_attribute *attr, char *buf)
 286 {
 287         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 288
 289         return sprintf(buf, "%d\n", fan_data->speed[fan_data->speed_index].rpm);
 290 }
 291
 292 static ssize_t set_rpm(struct device *dev, struct device_attribute *attr,
 293                        const char *buf, size_t count)
 294 {
 295         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 296         unsigned long rpm;
 297         int ret = count;
 298
 299         if (kstrtoul(buf, 10, &rpm))
 300                 return -EINVAL;
 301
 302         mutex_lock(&fan_data->lock);
 303
 304         if (!fan_data->pwm_enable) {
 305                 ret = -EPERM;
 306                 goto exit_unlock;
 307         }
 308
 309         set_fan_speed(fan_data, rpm_to_speed_index(fan_data, rpm));
 310
 311 exit_unlock:
 312         mutex_unlock(&fan_data->lock);
 313
 314         return ret;
 315 }
 316
 317 static DEVICE_ATTR_RW(pwm1);
 318 static DEVICE_ATTR_RW(pwm1_enable);
 319 static DEVICE_ATTR_RO(pwm1_mode);
 320 static DEVICE_ATTR_RO(fan1_min);
 321 static DEVICE_ATTR_RO(fan1_max);
 322 static DEVICE_ATTR_RO(fan1_input);
 323 static DEVICE_ATTR(fan1_target, S_IRUGO | S_IWUSR, fan1_input_show, set_rpm);
 324
 325 static umode_t gpio_fan_is_visible(struct kobject *kobj,
 326                                    struct attribute *attr, int index)
 327 {
 328         struct device *dev = container_of(kobj, struct device, kobj);
 329         struct gpio_fan_data *data = dev_get_drvdata(dev);
 330
 331         if (index == 0 && !data->alarm)
 332                 return 0;
 333         if (index > 0 && !data->ctrl)
 334                 return 0;
 335
 336         return attr->mode;
 337 }
 338
 339 static struct attribute *gpio_fan_attributes[] = {
 340         &dev_attr_fan1_alarm.attr,              /* 0 */
 341         &dev_attr_pwm1.attr,                    /* 1 */
 342         &dev_attr_pwm1_enable.attr,
 343         &dev_attr_pwm1_mode.attr,
 344         &dev_attr_fan1_input.attr,
 345         &dev_attr_fan1_target.attr,
 346         &dev_attr_fan1_min.attr,
 347         &dev_attr_fan1_max.attr,
 348         NULL
 349 };
 350
 351 static const struct attribute_group gpio_fan_group = {
 352         .attrs = gpio_fan_attributes,
 353         .is_visible = gpio_fan_is_visible,
 354 };
 355
 356 static const struct attribute_group *gpio_fan_groups[] = {
 357         &gpio_fan_group,
 358         NULL
 359 };
 360
 361 static int fan_ctrl_init(struct gpio_fan_data *fan_data,
 362                          struct gpio_fan_platform_data *pdata)
 363 {
 364         struct platform_device *pdev = fan_data->pdev;
 365         int num_ctrl = pdata->num_ctrl;
 366         unsigned *ctrl = pdata->ctrl;
 367         int i, err;
 368
 369         for (i = 0; i < num_ctrl; i++) {
 370                 err = devm_gpio_request(&pdev->dev, ctrl[i],
 371                                         "GPIO fan control");
 372                 if (err)
 373                         return err;
 374
 375                 err = gpio_direction_output(ctrl[i],
 376                                             gpio_get_value_cansleep(ctrl[i]));
 377                 if (err)
 378                         return err;
 379         }
 380
 381         fan_data->num_ctrl = num_ctrl;
 382         fan_data->ctrl = ctrl;
 383         fan_data->num_speed = pdata->num_speed;
 384         fan_data->speed = pdata->speed;
 385         fan_data->pwm_enable = true; /* Enable manual fan speed control. */
 386         fan_data->speed_index = get_fan_speed_index(fan_data);
 387         if (fan_data->speed_index < 0)
 388                 return fan_data->speed_index;
 389
 390         return 0;
 391 }
 392
 393 static int gpio_fan_get_max_state(struct thermal_cooling_device *cdev,
 394                                   unsigned long *state)
 395 {
 396         struct gpio_fan_data *fan_data = cdev->devdata;
 397
 398         if (!fan_data)
 399                 return -EINVAL;
 400
 401         *state = fan_data->num_speed - 1;
 402         return 0;
 403 }
 404
 405 static int gpio_fan_get_cur_state(struct thermal_cooling_device *cdev,
 406                                   unsigned long *state)
 407 {
 408         struct gpio_fan_data *fan_data = cdev->devdata;
 409
 410         if (!fan_data)
 411                 return -EINVAL;
 412
 413         *state = fan_data->speed_index;
 414         return 0;
 415 }
 416
 417 static int gpio_fan_set_cur_state(struct thermal_cooling_device *cdev,
 418                                   unsigned long state)
 419 {
 420         struct gpio_fan_data *fan_data = cdev->devdata;
 421
 422         if (!fan_data)
 423                 return -EINVAL;
 424
 425         set_fan_speed(fan_data, state);
 426         return 0;
 427 }
 428
 429 static const struct thermal_cooling_device_ops gpio_fan_cool_ops = {
 430         .get_max_state = gpio_fan_get_max_state,
 431         .get_cur_state = gpio_fan_get_cur_state,
 432         .set_cur_state = gpio_fan_set_cur_state,
 433 };
 434
 435 #ifdef CONFIG_OF_GPIO
 436 /*
 437  * Translate OpenFirmware node properties into platform_data
 438  */
 439 static int gpio_fan_get_of_pdata(struct device *dev,
 440                             struct gpio_fan_platform_data *pdata)
 441 {
 442         struct device_node *node;
 443         struct gpio_fan_speed *speed;
 444         unsigned *ctrl;
 445         unsigned i;
 446         u32 u;
 447         struct property *prop;
 448         const __be32 *p;
 449
 450         node = dev->of_node;
 451
 452         /* Alarm GPIO if one exists */
 453         if (of_gpio_named_count(node, "alarm-gpios") > 0) {
 454                 struct gpio_fan_alarm *alarm;
 455                 int val;
 456                 enum of_gpio_flags flags;
 457
 458                 alarm = devm_kzalloc(dev, sizeof(struct gpio_fan_alarm),
 459                                         GFP_KERNEL);
 460                 if (!alarm)
 461                         return -ENOMEM;
 462
 463                 val = of_get_named_gpio_flags(node, "alarm-gpios", 0, &flags);
 464                 if (val < 0)
 465                         return val;
 466                 alarm->gpio = val;
 467                 alarm->active_low = flags & OF_GPIO_ACTIVE_LOW;
 468
 469                 pdata->alarm = alarm;
 470         }
 471
 472         /* Fill GPIO pin array */
 473         pdata->num_ctrl = of_gpio_count(node);
 474         if (pdata->num_ctrl <= 0) {
 475                 if (pdata->alarm)
 476                         return 0;
 477                 dev_err(dev, "DT properties empty / missing");
 478                 return -ENODEV;
 479         }
 480         ctrl = devm_kzalloc(dev, pdata->num_ctrl * sizeof(unsigned),
 481                                 GFP_KERNEL);
 482         if (!ctrl)
 483                 return -ENOMEM;
 484         for (i = 0; i < pdata->num_ctrl; i++) {
 485                 int val;
 486
 487                 val = of_get_gpio(node, i);
 488                 if (val < 0)
 489                         return val;
 490                 ctrl[i] = val;
 491         }
 492         pdata->ctrl = ctrl;
 493
 494         /* Get number of RPM/ctrl_val pairs in speed map */
 495         prop = of_find_property(node, "gpio-fan,speed-map", &i);
 496         if (!prop) {
 497                 dev_err(dev, "gpio-fan,speed-map DT property missing");
 498                 return -ENODEV;
 499         }
 500         i = i / sizeof(u32);
 501         if (i == 0 || i & 1) {
 502                 dev_err(dev, "gpio-fan,speed-map contains zero/odd number of entries");
 503                 return -ENODEV;
 504         }
 505         pdata->num_speed = i / 2;
 506
 507         /*
 508          * Populate speed map
 509          * Speed map is in the form <RPM ctrl_val RPM ctrl_val ...>
 510          * this needs splitting into pairs to create gpio_fan_speed structs
 511          */
 512         speed = devm_kzalloc(dev,
 513                         pdata->num_speed * sizeof(struct gpio_fan_speed),
 514                         GFP_KERNEL);
 515         if (!speed)
 516                 return -ENOMEM;
 517         p = NULL;
 518         for (i = 0; i < pdata->num_speed; i++) {
 519                 p = of_prop_next_u32(prop, p, &u);
 520                 if (!p)
 521                         return -ENODEV;
 522                 speed[i].rpm = u;
 523                 p = of_prop_next_u32(prop, p, &u);
 524                 if (!p)
 525                         return -ENODEV;
 526                 speed[i].ctrl_val = u;
 527         }
 528         pdata->speed = speed;
 529
 530         return 0;
 531 }
 532
 533 static const struct of_device_id of_gpio_fan_match[] = {
 534         { .compatible = "gpio-fan", },
 535         {},
 536 };
 537 MODULE_DEVICE_TABLE(of, of_gpio_fan_match);
 538 #endif /* CONFIG_OF_GPIO */
 539
 540 static int gpio_fan_probe(struct platform_device *pdev)
 541 {
 542         int err;
 543         struct gpio_fan_data *fan_data;
 544         struct gpio_fan_platform_data *pdata = dev_get_platdata(&pdev->dev);
 545
 546         fan_data = devm_kzalloc(&pdev->dev, sizeof(struct gpio_fan_data),
 547                                 GFP_KERNEL);
 548         if (!fan_data)
 549                 return -ENOMEM;
 550
 551 #ifdef CONFIG_OF_GPIO
 552         if (!pdata) {
 553                 pdata = devm_kzalloc(&pdev->dev,
 554                                         sizeof(struct gpio_fan_platform_data),
 555                                         GFP_KERNEL);
 556                 if (!pdata)
 557                         return -ENOMEM;
 558
 559                 err = gpio_fan_get_of_pdata(&pdev->dev, pdata);
 560                 if (err)
 561                         return err;
 562         }
 563 #else /* CONFIG_OF_GPIO */
 564         if (!pdata)
 565                 return -EINVAL;
 566 #endif /* CONFIG_OF_GPIO */
 567
 568         fan_data->pdev = pdev;
 569         platform_set_drvdata(pdev, fan_data);
 570         mutex_init(&fan_data->lock);
 571
 572         /* Configure alarm GPIO if available. */
 573         if (pdata->alarm) {
 574                 err = fan_alarm_init(fan_data, pdata->alarm);
 575                 if (err)
 576                         return err;
 577         }
 578
 579         /* Configure control GPIOs if available. */
 580         if (pdata->ctrl && pdata->num_ctrl > 0) {
 581                 if (!pdata->speed || pdata->num_speed <= 1)
 582                         return -EINVAL;
 583                 err = fan_ctrl_init(fan_data, pdata);
 584                 if (err)
 585                         return err;
 586         }
 587
 588         /* Make this driver part of hwmon class. */
 589         fan_data->hwmon_dev =
 590                 devm_hwmon_device_register_with_groups(&pdev->dev,
 591                                                        "gpio_fan", fan_data,
 592                                                        gpio_fan_groups);
 593         if (IS_ERR(fan_data->hwmon_dev))
 594                 return PTR_ERR(fan_data->hwmon_dev);
 595 #ifdef CONFIG_OF_GPIO
 596         /* Optional cooling device register for Device tree platforms */
 597         fan_data->cdev = thermal_of_cooling_device_register(pdev->dev.of_node,
 598                                                             "gpio-fan",
 599                                                             fan_data,
 600                                                             &gpio_fan_cool_ops);
 601 #else /* CONFIG_OF_GPIO */
 602         /* Optional cooling device register for non Device tree platforms */
 603         fan_data->cdev = thermal_cooling_device_register("gpio-fan", fan_data,
 604                                                          &gpio_fan_cool_ops);
 605 #endif /* CONFIG_OF_GPIO */
 606
 607         dev_info(&pdev->dev, "GPIO fan initialized\n");
 608
 609         return 0;
 610 }
 611
 612 static int gpio_fan_remove(struct platform_device *pdev)
 613 {
 614         struct gpio_fan_data *fan_data = platform_get_drvdata(pdev);
 615
 616         if (!IS_ERR(fan_data->cdev))
 617                 thermal_cooling_device_unregister(fan_data->cdev);
 618
 619         if (fan_data->ctrl)
 620                 set_fan_speed(fan_data, 0);
 621
 622         return 0;
 623 }
 624
 625 static void gpio_fan_shutdown(struct platform_device *pdev)
 626 {
 627         gpio_fan_remove(pdev);
 628 }
 629
 630 #ifdef CONFIG_PM_SLEEP
 631 static int gpio_fan_suspend(struct device *dev)
 632 {
 633         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 634
 635         if (fan_data->ctrl) {
 636                 fan_data->resume_speed = fan_data->speed_index;
 637                 set_fan_speed(fan_data, 0);
 638         }
 639
 640         return 0;
 641 }
 642
 643 static int gpio_fan_resume(struct device *dev)
 644 {
 645         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 646
 647         if (fan_data->ctrl)
 648                 set_fan_speed(fan_data, fan_data->resume_speed);
 649
 650         return 0;
 651 }
 652
 653 static SIMPLE_DEV_PM_OPS(gpio_fan_pm, gpio_fan_suspend, gpio_fan_resume);
 654 #define GPIO_FAN_PM     (&gpio_fan_pm)
 655 #else
 656 #define GPIO_FAN_PM     NULL
 657 #endif
 658
 659 static struct platform_driver gpio_fan_driver = {
 660         .probe          = gpio_fan_probe,
 661         .remove         = gpio_fan_remove,
 662         .shutdown       = gpio_fan_shutdown,
 663         .driver = {
 664                 .name   = "gpio-fan",
 665                 .pm     = GPIO_FAN_PM,
 666 #ifdef CONFIG_OF_GPIO
 667                 .of_match_table = of_match_ptr(of_gpio_fan_match),
 668 #endif
 669         },
 670 };
 671
 672 module_platform_driver(gpio_fan_driver);
 673
 674 MODULE_AUTHOR("Simon Guinot <sguinot@lacie.com>");
 675 MODULE_DESCRIPTION("GPIO FAN driver");
 676 MODULE_LICENSE("GPL");
 677 MODULE_ALIAS("platform:gpio-fan");