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
  38 struct gpio_fan_data {
  39         struct platform_device  *pdev;
  40         struct device           *hwmon_dev;
  41         struct mutex            lock; /* lock GPIOs operations. */
  42         int                     num_ctrl;
  43         unsigned                *ctrl;
  44         int                     num_speed;
  45         struct gpio_fan_speed   *speed;
  46         int                     speed_index;
  47 #ifdef CONFIG_PM_SLEEP
  48         int                     resume_speed;
  49 #endif
  50         bool                    pwm_enable;
  51         struct gpio_fan_alarm   *alarm;
  52         struct work_struct      alarm_work;
  53 };
  54
  55 /*
  56  * Alarm GPIO.
  57  */
  58
  59 static void fan_alarm_notify(struct work_struct *ws)
  60 {
  61         struct gpio_fan_data *fan_data =
  62                 container_of(ws, struct gpio_fan_data, alarm_work);
  63
  64         sysfs_notify(&fan_data->pdev->dev.kobj, NULL, "fan1_alarm");
  65         kobject_uevent(&fan_data->pdev->dev.kobj, KOBJ_CHANGE);
  66 }
  67
  68 static irqreturn_t fan_alarm_irq_handler(int irq, void *dev_id)
  69 {
  70         struct gpio_fan_data *fan_data = dev_id;
  71
  72         schedule_work(&fan_data->alarm_work);
  73
  74         return IRQ_NONE;
  75 }
  76
  77 static ssize_t show_fan_alarm(struct device *dev,
  78                               struct device_attribute *attr, char *buf)
  79 {
  80         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
  81         struct gpio_fan_alarm *alarm = fan_data->alarm;
  82         int value = gpio_get_value(alarm->gpio);
  83
  84         if (alarm->active_low)
  85                 value = !value;
  86
  87         return sprintf(buf, "%d\n", value);
  88 }
  89
  90 static DEVICE_ATTR(fan1_alarm, S_IRUGO, show_fan_alarm, NULL);
  91
  92 static int fan_alarm_init(struct gpio_fan_data *fan_data,
  93                           struct gpio_fan_alarm *alarm)
  94 {
  95         int err;
  96         int alarm_irq;
  97         struct platform_device *pdev = fan_data->pdev;
  98
  99         fan_data->alarm = alarm;
 100
 101         err = devm_gpio_request(&pdev->dev, alarm->gpio, "GPIO fan alarm");
 102         if (err)
 103                 return err;
 104
 105         err = gpio_direction_input(alarm->gpio);
 106         if (err)
 107                 return err;
 108
 109         /*
 110          * If the alarm GPIO don't support interrupts, just leave
 111          * without initializing the fail notification support.
 112          */
 113         alarm_irq = gpio_to_irq(alarm->gpio);
 114         if (alarm_irq < 0)
 115                 return 0;
 116
 117         INIT_WORK(&fan_data->alarm_work, fan_alarm_notify);
 118         irq_set_irq_type(alarm_irq, IRQ_TYPE_EDGE_BOTH);
 119         err = devm_request_irq(&pdev->dev, alarm_irq, fan_alarm_irq_handler,
 120                                IRQF_SHARED, "GPIO fan alarm", fan_data);
 121         return err;
 122 }
 123
 124 /*
 125  * Control GPIOs.
 126  */
 127
 128 /* Must be called with fan_data->lock held, except during initialization. */
 129 static void __set_fan_ctrl(struct gpio_fan_data *fan_data, int ctrl_val)
 130 {
 131         int i;
 132
 133         for (i = 0; i < fan_data->num_ctrl; i++)
 134                 gpio_set_value(fan_data->ctrl[i], (ctrl_val >> i) & 1);
 135 }
 136
 137 static int __get_fan_ctrl(struct gpio_fan_data *fan_data)
 138 {
 139         int i;
 140         int ctrl_val = 0;
 141
 142         for (i = 0; i < fan_data->num_ctrl; i++) {
 143                 int value;
 144
 145                 value = gpio_get_value(fan_data->ctrl[i]);
 146                 ctrl_val |= (value << i);
 147         }
 148         return ctrl_val;
 149 }
 150
 151 /* Must be called with fan_data->lock held, except during initialization. */
 152 static void set_fan_speed(struct gpio_fan_data *fan_data, int speed_index)
 153 {
 154         if (fan_data->speed_index == speed_index)
 155                 return;
 156
 157         __set_fan_ctrl(fan_data, fan_data->speed[speed_index].ctrl_val);
 158         fan_data->speed_index = speed_index;
 159 }
 160
 161 static int get_fan_speed_index(struct gpio_fan_data *fan_data)
 162 {
 163         int ctrl_val = __get_fan_ctrl(fan_data);
 164         int i;
 165
 166         for (i = 0; i < fan_data->num_speed; i++)
 167                 if (fan_data->speed[i].ctrl_val == ctrl_val)
 168                         return i;
 169
 170         dev_warn(&fan_data->pdev->dev,
 171                  "missing speed array entry for GPIO value 0x%x\n", ctrl_val);
 172
 173         return -ENODEV;
 174 }
 175
 176 static int rpm_to_speed_index(struct gpio_fan_data *fan_data, int rpm)
 177 {
 178         struct gpio_fan_speed *speed = fan_data->speed;
 179         int i;
 180
 181         for (i = 0; i < fan_data->num_speed; i++)
 182                 if (speed[i].rpm >= rpm)
 183                         return i;
 184
 185         return fan_data->num_speed - 1;
 186 }
 187
 188 static ssize_t show_pwm(struct device *dev,
 189                         struct device_attribute *attr, char *buf)
 190 {
 191         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 192         u8 pwm = fan_data->speed_index * 255 / (fan_data->num_speed - 1);
 193
 194         return sprintf(buf, "%d\n", pwm);
 195 }
 196
 197 static ssize_t set_pwm(struct device *dev, struct device_attribute *attr,
 198                        const char *buf, size_t count)
 199 {
 200         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 201         unsigned long pwm;
 202         int speed_index;
 203         int ret = count;
 204
 205         if (kstrtoul(buf, 10, &pwm) || pwm > 255)
 206                 return -EINVAL;
 207
 208         mutex_lock(&fan_data->lock);
 209
 210         if (!fan_data->pwm_enable) {
 211                 ret = -EPERM;
 212                 goto exit_unlock;
 213         }
 214
 215         speed_index = DIV_ROUND_UP(pwm * (fan_data->num_speed - 1), 255);
 216         set_fan_speed(fan_data, speed_index);
 217
 218 exit_unlock:
 219         mutex_unlock(&fan_data->lock);
 220
 221         return ret;
 222 }
 223
 224 static ssize_t show_pwm_enable(struct device *dev,
 225                                struct device_attribute *attr, char *buf)
 226 {
 227         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 228
 229         return sprintf(buf, "%d\n", fan_data->pwm_enable);
 230 }
 231
 232 static ssize_t set_pwm_enable(struct device *dev, struct device_attribute *attr,
 233                               const char *buf, size_t count)
 234 {
 235         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 236         unsigned long val;
 237
 238         if (kstrtoul(buf, 10, &val) || val > 1)
 239                 return -EINVAL;
 240
 241         if (fan_data->pwm_enable == val)
 242                 return count;
 243
 244         mutex_lock(&fan_data->lock);
 245
 246         fan_data->pwm_enable = val;
 247
 248         /* Disable manual control mode: set fan at full speed. */
 249         if (val == 0)
 250                 set_fan_speed(fan_data, fan_data->num_speed - 1);
 251
 252         mutex_unlock(&fan_data->lock);
 253
 254         return count;
 255 }
 256
 257 static ssize_t show_pwm_mode(struct device *dev,
 258                              struct device_attribute *attr, char *buf)
 259 {
 260         return sprintf(buf, "0\n");
 261 }
 262
 263 static ssize_t show_rpm_min(struct device *dev,
 264                             struct device_attribute *attr, char *buf)
 265 {
 266         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 267
 268         return sprintf(buf, "%d\n", fan_data->speed[0].rpm);
 269 }
 270
 271 static ssize_t show_rpm_max(struct device *dev,
 272                             struct device_attribute *attr, char *buf)
 273 {
 274         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 275
 276         return sprintf(buf, "%d\n",
 277                        fan_data->speed[fan_data->num_speed - 1].rpm);
 278 }
 279
 280 static ssize_t show_rpm(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[fan_data->speed_index].rpm);
 286 }
 287
 288 static ssize_t set_rpm(struct device *dev, struct device_attribute *attr,
 289                        const char *buf, size_t count)
 290 {
 291         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 292         unsigned long rpm;
 293         int ret = count;
 294
 295         if (kstrtoul(buf, 10, &rpm))
 296                 return -EINVAL;
 297
 298         mutex_lock(&fan_data->lock);
 299
 300         if (!fan_data->pwm_enable) {
 301                 ret = -EPERM;
 302                 goto exit_unlock;
 303         }
 304
 305         set_fan_speed(fan_data, rpm_to_speed_index(fan_data, rpm));
 306
 307 exit_unlock:
 308         mutex_unlock(&fan_data->lock);
 309
 310         return ret;
 311 }
 312
 313 static DEVICE_ATTR(pwm1, S_IRUGO | S_IWUSR, show_pwm, set_pwm);
 314 static DEVICE_ATTR(pwm1_enable, S_IRUGO | S_IWUSR,
 315                    show_pwm_enable, set_pwm_enable);
 316 static DEVICE_ATTR(pwm1_mode, S_IRUGO, show_pwm_mode, NULL);
 317 static DEVICE_ATTR(fan1_min, S_IRUGO, show_rpm_min, NULL);
 318 static DEVICE_ATTR(fan1_max, S_IRUGO, show_rpm_max, NULL);
 319 static DEVICE_ATTR(fan1_input, S_IRUGO, show_rpm, NULL);
 320 static DEVICE_ATTR(fan1_target, S_IRUGO | S_IWUSR, show_rpm, set_rpm);
 321
 322 static umode_t gpio_fan_is_visible(struct kobject *kobj,
 323                                    struct attribute *attr, int index)
 324 {
 325         struct device *dev = container_of(kobj, struct device, kobj);
 326         struct gpio_fan_data *data = dev_get_drvdata(dev);
 327
 328         if (index == 0 && !data->alarm)
 329                 return 0;
 330         if (index > 0 && !data->ctrl)
 331                 return 0;
 332
 333         return attr->mode;
 334 }
 335
 336 static struct attribute *gpio_fan_attributes[] = {
 337         &dev_attr_fan1_alarm.attr,              /* 0 */
 338         &dev_attr_pwm1.attr,                    /* 1 */
 339         &dev_attr_pwm1_enable.attr,
 340         &dev_attr_pwm1_mode.attr,
 341         &dev_attr_fan1_input.attr,
 342         &dev_attr_fan1_target.attr,
 343         &dev_attr_fan1_min.attr,
 344         &dev_attr_fan1_max.attr,
 345         NULL
 346 };
 347
 348 static const struct attribute_group gpio_fan_group = {
 349         .attrs = gpio_fan_attributes,
 350         .is_visible = gpio_fan_is_visible,
 351 };
 352
 353 static const struct attribute_group *gpio_fan_groups[] = {
 354         &gpio_fan_group,
 355         NULL
 356 };
 357
 358 static int fan_ctrl_init(struct gpio_fan_data *fan_data,
 359                          struct gpio_fan_platform_data *pdata)
 360 {
 361         struct platform_device *pdev = fan_data->pdev;
 362         int num_ctrl = pdata->num_ctrl;
 363         unsigned *ctrl = pdata->ctrl;
 364         int i, err;
 365
 366         for (i = 0; i < num_ctrl; i++) {
 367                 err = devm_gpio_request(&pdev->dev, ctrl[i],
 368                                         "GPIO fan control");
 369                 if (err)
 370                         return err;
 371
 372                 err = gpio_direction_output(ctrl[i], gpio_get_value(ctrl[i]));
 373                 if (err)
 374                         return err;
 375         }
 376
 377         fan_data->num_ctrl = num_ctrl;
 378         fan_data->ctrl = ctrl;
 379         fan_data->num_speed = pdata->num_speed;
 380         fan_data->speed = pdata->speed;
 381         fan_data->pwm_enable = true; /* Enable manual fan speed control. */
 382         fan_data->speed_index = get_fan_speed_index(fan_data);
 383         if (fan_data->speed_index < 0)
 384                 return fan_data->speed_index;
 385
 386         return 0;
 387 }
 388
 389 #ifdef CONFIG_OF_GPIO
 390 /*
 391  * Translate OpenFirmware node properties into platform_data
 392  */
 393 static int gpio_fan_get_of_pdata(struct device *dev,
 394                             struct gpio_fan_platform_data *pdata)
 395 {
 396         struct device_node *node;
 397         struct gpio_fan_speed *speed;
 398         unsigned *ctrl;
 399         unsigned i;
 400         u32 u;
 401         struct property *prop;
 402         const __be32 *p;
 403
 404         node = dev->of_node;
 405
 406         /* Fill GPIO pin array */
 407         pdata->num_ctrl = of_gpio_count(node);
 408         if (pdata->num_ctrl <= 0) {
 409                 dev_err(dev, "gpios DT property empty / missing");
 410                 return -ENODEV;
 411         }
 412         ctrl = devm_kzalloc(dev, pdata->num_ctrl * sizeof(unsigned),
 413                                 GFP_KERNEL);
 414         if (!ctrl)
 415                 return -ENOMEM;
 416         for (i = 0; i < pdata->num_ctrl; i++) {
 417                 int val;
 418
 419                 val = of_get_gpio(node, i);
 420                 if (val < 0)
 421                         return val;
 422                 ctrl[i] = val;
 423         }
 424         pdata->ctrl = ctrl;
 425
 426         /* Get number of RPM/ctrl_val pairs in speed map */
 427         prop = of_find_property(node, "gpio-fan,speed-map", &i);
 428         if (!prop) {
 429                 dev_err(dev, "gpio-fan,speed-map DT property missing");
 430                 return -ENODEV;
 431         }
 432         i = i / sizeof(u32);
 433         if (i == 0 || i & 1) {
 434                 dev_err(dev, "gpio-fan,speed-map contains zero/odd number of entries");
 435                 return -ENODEV;
 436         }
 437         pdata->num_speed = i / 2;
 438
 439         /*
 440          * Populate speed map
 441          * Speed map is in the form <RPM ctrl_val RPM ctrl_val ...>
 442          * this needs splitting into pairs to create gpio_fan_speed structs
 443          */
 444         speed = devm_kzalloc(dev,
 445                         pdata->num_speed * sizeof(struct gpio_fan_speed),
 446                         GFP_KERNEL);
 447         if (!speed)
 448                 return -ENOMEM;
 449         p = NULL;
 450         for (i = 0; i < pdata->num_speed; i++) {
 451                 p = of_prop_next_u32(prop, p, &u);
 452                 if (!p)
 453                         return -ENODEV;
 454                 speed[i].rpm = u;
 455                 p = of_prop_next_u32(prop, p, &u);
 456                 if (!p)
 457                         return -ENODEV;
 458                 speed[i].ctrl_val = u;
 459         }
 460         pdata->speed = speed;
 461
 462         /* Alarm GPIO if one exists */
 463         if (of_gpio_named_count(node, "alarm-gpios") > 0) {
 464                 struct gpio_fan_alarm *alarm;
 465                 int val;
 466                 enum of_gpio_flags flags;
 467
 468                 alarm = devm_kzalloc(dev, sizeof(struct gpio_fan_alarm),
 469                                         GFP_KERNEL);
 470                 if (!alarm)
 471                         return -ENOMEM;
 472
 473                 val = of_get_named_gpio_flags(node, "alarm-gpios", 0, &flags);
 474                 if (val < 0)
 475                         return val;
 476                 alarm->gpio = val;
 477                 alarm->active_low = flags & OF_GPIO_ACTIVE_LOW;
 478
 479                 pdata->alarm = alarm;
 480         }
 481
 482         return 0;
 483 }
 484
 485 static struct of_device_id of_gpio_fan_match[] = {
 486         { .compatible = "gpio-fan", },
 487         {},
 488 };
 489 #endif /* CONFIG_OF_GPIO */
 490
 491 static int gpio_fan_probe(struct platform_device *pdev)
 492 {
 493         int err;
 494         struct gpio_fan_data *fan_data;
 495         struct gpio_fan_platform_data *pdata = dev_get_platdata(&pdev->dev);
 496
 497 #ifdef CONFIG_OF_GPIO
 498         if (!pdata) {
 499                 pdata = devm_kzalloc(&pdev->dev,
 500                                         sizeof(struct gpio_fan_platform_data),
 501                                         GFP_KERNEL);
 502                 if (!pdata)
 503                         return -ENOMEM;
 504
 505                 err = gpio_fan_get_of_pdata(&pdev->dev, pdata);
 506                 if (err)
 507                         return err;
 508         }
 509 #else /* CONFIG_OF_GPIO */
 510         if (!pdata)
 511                 return -EINVAL;
 512 #endif /* CONFIG_OF_GPIO */
 513
 514         fan_data = devm_kzalloc(&pdev->dev, sizeof(struct gpio_fan_data),
 515                                 GFP_KERNEL);
 516         if (!fan_data)
 517                 return -ENOMEM;
 518
 519         fan_data->pdev = pdev;
 520         platform_set_drvdata(pdev, fan_data);
 521         mutex_init(&fan_data->lock);
 522
 523         /* Configure alarm GPIO if available. */
 524         if (pdata->alarm) {
 525                 err = fan_alarm_init(fan_data, pdata->alarm);
 526                 if (err)
 527                         return err;
 528         }
 529
 530         /* Configure control GPIOs if available. */
 531         if (pdata->ctrl && pdata->num_ctrl > 0) {
 532                 if (!pdata->speed || pdata->num_speed <= 1)
 533                         return -EINVAL;
 534                 err = fan_ctrl_init(fan_data, pdata);
 535                 if (err)
 536                         return err;
 537         }
 538
 539         /* Make this driver part of hwmon class. */
 540         fan_data->hwmon_dev = hwmon_device_register_with_groups(&pdev->dev,
 541                                                 "gpio-fan", fan_data,
 542                                                 gpio_fan_groups);
 543         if (IS_ERR(fan_data->hwmon_dev))
 544                 return PTR_ERR(fan_data->hwmon_dev);
 545
 546         dev_info(&pdev->dev, "GPIO fan initialized\n");
 547
 548         return 0;
 549 }
 550
 551 static int gpio_fan_remove(struct platform_device *pdev)
 552 {
 553         struct gpio_fan_data *fan_data = platform_get_drvdata(pdev);
 554
 555         hwmon_device_unregister(fan_data->hwmon_dev);
 556
 557         return 0;
 558 }
 559
 560 #ifdef CONFIG_PM_SLEEP
 561 static int gpio_fan_suspend(struct device *dev)
 562 {
 563         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 564
 565         if (fan_data->ctrl) {
 566                 fan_data->resume_speed = fan_data->speed_index;
 567                 set_fan_speed(fan_data, 0);
 568         }
 569
 570         return 0;
 571 }
 572
 573 static int gpio_fan_resume(struct device *dev)
 574 {
 575         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 576
 577         if (fan_data->ctrl)
 578                 set_fan_speed(fan_data, fan_data->resume_speed);
 579
 580         return 0;
 581 }
 582
 583 static SIMPLE_DEV_PM_OPS(gpio_fan_pm, gpio_fan_suspend, gpio_fan_resume);
 584 #define GPIO_FAN_PM     (&gpio_fan_pm)
 585 #else
 586 #define GPIO_FAN_PM     NULL
 587 #endif
 588
 589 static struct platform_driver gpio_fan_driver = {
 590         .probe          = gpio_fan_probe,
 591         .remove         = gpio_fan_remove,
 592         .driver = {
 593                 .name   = "gpio-fan",
 594                 .pm     = GPIO_FAN_PM,
 595 #ifdef CONFIG_OF_GPIO
 596                 .of_match_table = of_match_ptr(of_gpio_fan_match),
 597 #endif
 598         },
 599 };
 600
 601 module_platform_driver(gpio_fan_driver);
 602
 603 MODULE_AUTHOR("Simon Guinot <sguinot@lacie.com>");
 604 MODULE_DESCRIPTION("GPIO FAN driver");
 605 MODULE_LICENSE("GPL");
 606 MODULE_ALIAS("platform:gpio-fan");