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_platform.h>
  35 #include <linux/of_gpio.h>
  36
  37 struct gpio_fan_data {
  38         struct platform_device  *pdev;
  39         struct device           *hwmon_dev;
  40         struct mutex            lock; /* lock GPIOs operations. */
  41         int                     num_ctrl;
  42         unsigned                *ctrl;
  43         int                     num_speed;
  44         struct gpio_fan_speed   *speed;
  45         int                     speed_index;
  46 #ifdef CONFIG_PM_SLEEP
  47         int                     resume_speed;
  48 #endif
  49         bool                    pwm_enable;
  50         struct gpio_fan_alarm   *alarm;
  51         struct work_struct      alarm_work;
  52 };
  53
  54 /*
  55  * Alarm GPIO.
  56  */
  57
  58 static void fan_alarm_notify(struct work_struct *ws)
  59 {
  60         struct gpio_fan_data *fan_data =
  61                 container_of(ws, struct gpio_fan_data, alarm_work);
  62
  63         sysfs_notify(&fan_data->pdev->dev.kobj, NULL, "fan1_alarm");
  64         kobject_uevent(&fan_data->pdev->dev.kobj, KOBJ_CHANGE);
  65 }
  66
  67 static irqreturn_t fan_alarm_irq_handler(int irq, void *dev_id)
  68 {
  69         struct gpio_fan_data *fan_data = dev_id;
  70
  71         schedule_work(&fan_data->alarm_work);
  72
  73         return IRQ_NONE;
  74 }
  75
  76 static ssize_t show_fan_alarm(struct device *dev,
  77                               struct device_attribute *attr, char *buf)
  78 {
  79         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
  80         struct gpio_fan_alarm *alarm = fan_data->alarm;
  81         int value = gpio_get_value(alarm->gpio);
  82
  83         if (alarm->active_low)
  84                 value = !value;
  85
  86         return sprintf(buf, "%d\n", value);
  87 }
  88
  89 static DEVICE_ATTR(fan1_alarm, S_IRUGO, show_fan_alarm, NULL);
  90
  91 static int fan_alarm_init(struct gpio_fan_data *fan_data,
  92                           struct gpio_fan_alarm *alarm)
  93 {
  94         int err;
  95         int alarm_irq;
  96         struct platform_device *pdev = fan_data->pdev;
  97
  98         fan_data->alarm = alarm;
  99
 100         err = devm_gpio_request(&pdev->dev, alarm->gpio, "GPIO fan alarm");
 101         if (err)
 102                 return err;
 103
 104         err = gpio_direction_input(alarm->gpio);
 105         if (err)
 106                 return err;
 107
 108         err = device_create_file(&pdev->dev, &dev_attr_fan1_alarm);
 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         if (err)
 125                 goto err_free_sysfs;
 126
 127         return 0;
 128
 129 err_free_sysfs:
 130         device_remove_file(&pdev->dev, &dev_attr_fan1_alarm);
 131         return err;
 132 }
 133
 134 static void fan_alarm_free(struct gpio_fan_data *fan_data)
 135 {
 136         struct platform_device *pdev = fan_data->pdev;
 137
 138         device_remove_file(&pdev->dev, &dev_attr_fan1_alarm);
 139 }
 140
 141 /*
 142  * Control GPIOs.
 143  */
 144
 145 /* Must be called with fan_data->lock held, except during initialization. */
 146 static void __set_fan_ctrl(struct gpio_fan_data *fan_data, int ctrl_val)
 147 {
 148         int i;
 149
 150         for (i = 0; i < fan_data->num_ctrl; i++)
 151                 gpio_set_value(fan_data->ctrl[i], (ctrl_val >> i) & 1);
 152 }
 153
 154 static int __get_fan_ctrl(struct gpio_fan_data *fan_data)
 155 {
 156         int i;
 157         int ctrl_val = 0;
 158
 159         for (i = 0; i < fan_data->num_ctrl; i++) {
 160                 int value;
 161
 162                 value = gpio_get_value(fan_data->ctrl[i]);
 163                 ctrl_val |= (value << i);
 164         }
 165         return ctrl_val;
 166 }
 167
 168 /* Must be called with fan_data->lock held, except during initialization. */
 169 static void set_fan_speed(struct gpio_fan_data *fan_data, int speed_index)
 170 {
 171         if (fan_data->speed_index == speed_index)
 172                 return;
 173
 174         __set_fan_ctrl(fan_data, fan_data->speed[speed_index].ctrl_val);
 175         fan_data->speed_index = speed_index;
 176 }
 177
 178 static int get_fan_speed_index(struct gpio_fan_data *fan_data)
 179 {
 180         int ctrl_val = __get_fan_ctrl(fan_data);
 181         int i;
 182
 183         for (i = 0; i < fan_data->num_speed; i++)
 184                 if (fan_data->speed[i].ctrl_val == ctrl_val)
 185                         return i;
 186
 187         dev_warn(&fan_data->pdev->dev,
 188                  "missing speed array entry for GPIO value 0x%x\n", ctrl_val);
 189
 190         return -EINVAL;
 191 }
 192
 193 static int rpm_to_speed_index(struct gpio_fan_data *fan_data, int rpm)
 194 {
 195         struct gpio_fan_speed *speed = fan_data->speed;
 196         int i;
 197
 198         for (i = 0; i < fan_data->num_speed; i++)
 199                 if (speed[i].rpm >= rpm)
 200                         return i;
 201
 202         return fan_data->num_speed - 1;
 203 }
 204
 205 static ssize_t show_pwm(struct device *dev,
 206                         struct device_attribute *attr, char *buf)
 207 {
 208         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 209         u8 pwm = fan_data->speed_index * 255 / (fan_data->num_speed - 1);
 210
 211         return sprintf(buf, "%d\n", pwm);
 212 }
 213
 214 static ssize_t set_pwm(struct device *dev, struct device_attribute *attr,
 215                        const char *buf, size_t count)
 216 {
 217         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 218         unsigned long pwm;
 219         int speed_index;
 220         int ret = count;
 221
 222         if (kstrtoul(buf, 10, &pwm) || pwm > 255)
 223                 return -EINVAL;
 224
 225         mutex_lock(&fan_data->lock);
 226
 227         if (!fan_data->pwm_enable) {
 228                 ret = -EPERM;
 229                 goto exit_unlock;
 230         }
 231
 232         speed_index = DIV_ROUND_UP(pwm * (fan_data->num_speed - 1), 255);
 233         set_fan_speed(fan_data, speed_index);
 234
 235 exit_unlock:
 236         mutex_unlock(&fan_data->lock);
 237
 238         return ret;
 239 }
 240
 241 static ssize_t show_pwm_enable(struct device *dev,
 242                                struct device_attribute *attr, char *buf)
 243 {
 244         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 245
 246         return sprintf(buf, "%d\n", fan_data->pwm_enable);
 247 }
 248
 249 static ssize_t set_pwm_enable(struct device *dev, struct device_attribute *attr,
 250                               const char *buf, size_t count)
 251 {
 252         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 253         unsigned long val;
 254
 255         if (kstrtoul(buf, 10, &val) || val > 1)
 256                 return -EINVAL;
 257
 258         if (fan_data->pwm_enable == val)
 259                 return count;
 260
 261         mutex_lock(&fan_data->lock);
 262
 263         fan_data->pwm_enable = val;
 264
 265         /* Disable manual control mode: set fan at full speed. */
 266         if (val == 0)
 267                 set_fan_speed(fan_data, fan_data->num_speed - 1);
 268
 269         mutex_unlock(&fan_data->lock);
 270
 271         return count;
 272 }
 273
 274 static ssize_t show_pwm_mode(struct device *dev,
 275                              struct device_attribute *attr, char *buf)
 276 {
 277         return sprintf(buf, "0\n");
 278 }
 279
 280 static ssize_t show_rpm_min(struct device *dev,
 281                             struct device_attribute *attr, char *buf)
 282 {
 283         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 284
 285         return sprintf(buf, "%d\n", fan_data->speed[0].rpm);
 286 }
 287
 288 static ssize_t show_rpm_max(struct device *dev,
 289                             struct device_attribute *attr, char *buf)
 290 {
 291         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 292
 293         return sprintf(buf, "%d\n",
 294                        fan_data->speed[fan_data->num_speed - 1].rpm);
 295 }
 296
 297 static ssize_t show_rpm(struct device *dev,
 298                         struct device_attribute *attr, char *buf)
 299 {
 300         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 301
 302         return sprintf(buf, "%d\n", fan_data->speed[fan_data->speed_index].rpm);
 303 }
 304
 305 static ssize_t set_rpm(struct device *dev, struct device_attribute *attr,
 306                        const char *buf, size_t count)
 307 {
 308         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 309         unsigned long rpm;
 310         int ret = count;
 311
 312         if (kstrtoul(buf, 10, &rpm))
 313                 return -EINVAL;
 314
 315         mutex_lock(&fan_data->lock);
 316
 317         if (!fan_data->pwm_enable) {
 318                 ret = -EPERM;
 319                 goto exit_unlock;
 320         }
 321
 322         set_fan_speed(fan_data, rpm_to_speed_index(fan_data, rpm));
 323
 324 exit_unlock:
 325         mutex_unlock(&fan_data->lock);
 326
 327         return ret;
 328 }
 329
 330 static DEVICE_ATTR(pwm1, S_IRUGO | S_IWUSR, show_pwm, set_pwm);
 331 static DEVICE_ATTR(pwm1_enable, S_IRUGO | S_IWUSR,
 332                    show_pwm_enable, set_pwm_enable);
 333 static DEVICE_ATTR(pwm1_mode, S_IRUGO, show_pwm_mode, NULL);
 334 static DEVICE_ATTR(fan1_min, S_IRUGO, show_rpm_min, NULL);
 335 static DEVICE_ATTR(fan1_max, S_IRUGO, show_rpm_max, NULL);
 336 static DEVICE_ATTR(fan1_input, S_IRUGO, show_rpm, NULL);
 337 static DEVICE_ATTR(fan1_target, S_IRUGO | S_IWUSR, show_rpm, set_rpm);
 338
 339 static struct attribute *gpio_fan_ctrl_attributes[] = {
 340         &dev_attr_pwm1.attr,
 341         &dev_attr_pwm1_enable.attr,
 342         &dev_attr_pwm1_mode.attr,
 343         &dev_attr_fan1_input.attr,
 344         &dev_attr_fan1_target.attr,
 345         &dev_attr_fan1_min.attr,
 346         &dev_attr_fan1_max.attr,
 347         NULL
 348 };
 349
 350 static const struct attribute_group gpio_fan_ctrl_group = {
 351         .attrs = gpio_fan_ctrl_attributes,
 352 };
 353
 354 static int fan_ctrl_init(struct gpio_fan_data *fan_data,
 355                          struct gpio_fan_platform_data *pdata)
 356 {
 357         struct platform_device *pdev = fan_data->pdev;
 358         int num_ctrl = pdata->num_ctrl;
 359         unsigned *ctrl = pdata->ctrl;
 360         int i, err;
 361
 362         for (i = 0; i < num_ctrl; i++) {
 363                 err = devm_gpio_request(&pdev->dev, ctrl[i],
 364                                         "GPIO fan control");
 365                 if (err)
 366                         return err;
 367
 368                 err = gpio_direction_output(ctrl[i], gpio_get_value(ctrl[i]));
 369                 if (err)
 370                         return err;
 371         }
 372
 373         fan_data->num_ctrl = num_ctrl;
 374         fan_data->ctrl = ctrl;
 375         fan_data->num_speed = pdata->num_speed;
 376         fan_data->speed = pdata->speed;
 377         fan_data->pwm_enable = true; /* Enable manual fan speed control. */
 378         fan_data->speed_index = get_fan_speed_index(fan_data);
 379         if (fan_data->speed_index < 0)
 380                 return -ENODEV;
 381
 382         err = sysfs_create_group(&pdev->dev.kobj, &gpio_fan_ctrl_group);
 383         return err;
 384 }
 385
 386 static void fan_ctrl_free(struct gpio_fan_data *fan_data)
 387 {
 388         struct platform_device *pdev = fan_data->pdev;
 389
 390         sysfs_remove_group(&pdev->dev.kobj, &gpio_fan_ctrl_group);
 391 }
 392
 393 /*
 394  * Platform driver.
 395  */
 396
 397 static ssize_t show_name(struct device *dev,
 398                          struct device_attribute *attr, char *buf)
 399 {
 400         return sprintf(buf, "gpio-fan\n");
 401 }
 402
 403 static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
 404
 405
 406 #ifdef CONFIG_OF_GPIO
 407 /*
 408  * Translate OpenFirmware node properties into platform_data
 409  */
 410 static int gpio_fan_get_of_pdata(struct device *dev,
 411                             struct gpio_fan_platform_data *pdata)
 412 {
 413         struct device_node *node;
 414         struct gpio_fan_speed *speed;
 415         unsigned *ctrl;
 416         unsigned i;
 417         u32 u;
 418         struct property *prop;
 419         const __be32 *p;
 420
 421         node = dev->of_node;
 422
 423         /* Fill GPIO pin array */
 424         pdata->num_ctrl = of_gpio_count(node);
 425         if (!pdata->num_ctrl) {
 426                 dev_err(dev, "gpios DT property empty / missing");
 427                 return -ENODEV;
 428         }
 429         ctrl = devm_kzalloc(dev, pdata->num_ctrl * sizeof(unsigned),
 430                                 GFP_KERNEL);
 431         if (!ctrl)
 432                 return -ENOMEM;
 433         for (i = 0; i < pdata->num_ctrl; i++) {
 434                 int val;
 435
 436                 val = of_get_gpio(node, i);
 437                 if (val < 0)
 438                         return val;
 439                 ctrl[i] = val;
 440         }
 441         pdata->ctrl = ctrl;
 442
 443         /* Get number of RPM/ctrl_val pairs in speed map */
 444         prop = of_find_property(node, "gpio-fan,speed-map", &i);
 445         if (!prop) {
 446                 dev_err(dev, "gpio-fan,speed-map DT property missing");
 447                 return -ENODEV;
 448         }
 449         i = i / sizeof(u32);
 450         if (i == 0 || i & 1) {
 451                 dev_err(dev, "gpio-fan,speed-map contains zero/odd number of entries");
 452                 return -ENODEV;
 453         }
 454         pdata->num_speed = i / 2;
 455
 456         /*
 457          * Populate speed map
 458          * Speed map is in the form <RPM ctrl_val RPM ctrl_val ...>
 459          * this needs splitting into pairs to create gpio_fan_speed structs
 460          */
 461         speed = devm_kzalloc(dev,
 462                         pdata->num_speed * sizeof(struct gpio_fan_speed),
 463                         GFP_KERNEL);
 464         if (!speed)
 465                 return -ENOMEM;
 466         p = NULL;
 467         for (i = 0; i < pdata->num_speed; i++) {
 468                 p = of_prop_next_u32(prop, p, &u);
 469                 if (!p)
 470                         return -ENODEV;
 471                 speed[i].rpm = u;
 472                 p = of_prop_next_u32(prop, p, &u);
 473                 if (!p)
 474                         return -ENODEV;
 475                 speed[i].ctrl_val = u;
 476         }
 477         pdata->speed = speed;
 478
 479         /* Alarm GPIO if one exists */
 480         if (of_gpio_named_count(node, "alarm-gpios")) {
 481                 struct gpio_fan_alarm *alarm;
 482                 int val;
 483                 enum of_gpio_flags flags;
 484
 485                 alarm = devm_kzalloc(dev, sizeof(struct gpio_fan_alarm),
 486                                         GFP_KERNEL);
 487                 if (!alarm)
 488                         return -ENOMEM;
 489
 490                 val = of_get_named_gpio_flags(node, "alarm-gpios", 0, &flags);
 491                 if (val < 0)
 492                         return val;
 493                 alarm->gpio = val;
 494                 alarm->active_low = flags & OF_GPIO_ACTIVE_LOW;
 495
 496                 pdata->alarm = alarm;
 497         }
 498
 499         return 0;
 500 }
 501
 502 static struct of_device_id of_gpio_fan_match[] = {
 503         { .compatible = "gpio-fan", },
 504         {},
 505 };
 506 #endif /* CONFIG_OF_GPIO */
 507
 508 static int gpio_fan_probe(struct platform_device *pdev)
 509 {
 510         int err;
 511         struct gpio_fan_data *fan_data;
 512         struct gpio_fan_platform_data *pdata = pdev->dev.platform_data;
 513
 514 #ifdef CONFIG_OF_GPIO
 515         if (!pdata) {
 516                 pdata = devm_kzalloc(&pdev->dev,
 517                                         sizeof(struct gpio_fan_platform_data),
 518                                         GFP_KERNEL);
 519                 if (!pdata)
 520                         return -ENOMEM;
 521
 522                 err = gpio_fan_get_of_pdata(&pdev->dev, pdata);
 523                 if (err)
 524                         return err;
 525         }
 526 #else /* CONFIG_OF_GPIO */
 527         if (!pdata)
 528                 return -EINVAL;
 529 #endif /* CONFIG_OF_GPIO */
 530
 531         fan_data = devm_kzalloc(&pdev->dev, sizeof(struct gpio_fan_data),
 532                                 GFP_KERNEL);
 533         if (!fan_data)
 534                 return -ENOMEM;
 535
 536         fan_data->pdev = pdev;
 537         platform_set_drvdata(pdev, fan_data);
 538         mutex_init(&fan_data->lock);
 539
 540         /* Configure alarm GPIO if available. */
 541         if (pdata->alarm) {
 542                 err = fan_alarm_init(fan_data, pdata->alarm);
 543                 if (err)
 544                         return err;
 545         }
 546
 547         /* Configure control GPIOs if available. */
 548         if (pdata->ctrl && pdata->num_ctrl > 0) {
 549                 if (!pdata->speed || pdata->num_speed <= 1) {
 550                         err = -EINVAL;
 551                         goto err_free_alarm;
 552                 }
 553                 err = fan_ctrl_init(fan_data, pdata);
 554                 if (err)
 555                         goto err_free_alarm;
 556         }
 557
 558         err = device_create_file(&pdev->dev, &dev_attr_name);
 559         if (err)
 560                 goto err_free_ctrl;
 561
 562         /* Make this driver part of hwmon class. */
 563         fan_data->hwmon_dev = hwmon_device_register(&pdev->dev);
 564         if (IS_ERR(fan_data->hwmon_dev)) {
 565                 err = PTR_ERR(fan_data->hwmon_dev);
 566                 goto err_remove_name;
 567         }
 568
 569         dev_info(&pdev->dev, "GPIO fan initialized\n");
 570
 571         return 0;
 572
 573 err_remove_name:
 574         device_remove_file(&pdev->dev, &dev_attr_name);
 575 err_free_ctrl:
 576         if (fan_data->ctrl)
 577                 fan_ctrl_free(fan_data);
 578 err_free_alarm:
 579         if (fan_data->alarm)
 580                 fan_alarm_free(fan_data);
 581         return err;
 582 }
 583
 584 static int gpio_fan_remove(struct platform_device *pdev)
 585 {
 586         struct gpio_fan_data *fan_data = platform_get_drvdata(pdev);
 587
 588         hwmon_device_unregister(fan_data->hwmon_dev);
 589         device_remove_file(&pdev->dev, &dev_attr_name);
 590         if (fan_data->alarm)
 591                 fan_alarm_free(fan_data);
 592         if (fan_data->ctrl)
 593                 fan_ctrl_free(fan_data);
 594
 595         return 0;
 596 }
 597
 598 #ifdef CONFIG_PM_SLEEP
 599 static int gpio_fan_suspend(struct device *dev)
 600 {
 601         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 602
 603         if (fan_data->ctrl) {
 604                 fan_data->resume_speed = fan_data->speed_index;
 605                 set_fan_speed(fan_data, 0);
 606         }
 607
 608         return 0;
 609 }
 610
 611 static int gpio_fan_resume(struct device *dev)
 612 {
 613         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 614
 615         if (fan_data->ctrl)
 616                 set_fan_speed(fan_data, fan_data->resume_speed);
 617
 618         return 0;
 619 }
 620
 621 static SIMPLE_DEV_PM_OPS(gpio_fan_pm, gpio_fan_suspend, gpio_fan_resume);
 622 #define GPIO_FAN_PM     &gpio_fan_pm
 623 #else
 624 #define GPIO_FAN_PM     NULL
 625 #endif
 626
 627 static struct platform_driver gpio_fan_driver = {
 628         .probe          = gpio_fan_probe,
 629         .remove         = gpio_fan_remove,
 630         .driver = {
 631                 .name   = "gpio-fan",
 632                 .pm     = GPIO_FAN_PM,
 633 #ifdef CONFIG_OF_GPIO
 634                 .of_match_table = of_match_ptr(of_gpio_fan_match),
 635 #endif
 636         },
 637 };
 638
 639 module_platform_driver(gpio_fan_driver);
 640
 641 MODULE_AUTHOR("Simon Guinot <sguinot@lacie.com>");
 642 MODULE_DESCRIPTION("GPIO FAN driver");
 643 MODULE_LICENSE("GPL");
 644 MODULE_ALIAS("platform:gpio-fan");