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/consumer.h>
  33 #include <linux/of.h>
  34 #include <linux/of_platform.h>
  35 #include <linux/thermal.h>
  36
  37 struct gpio_fan_speed {
  38         int rpm;
  39         int ctrl_val;
  40 };
  41
  42 struct gpio_fan_data {
  43         struct device           *dev;
  44         struct device           *hwmon_dev;
  45         /* Cooling device if any */
  46         struct thermal_cooling_device *cdev;
  47         struct mutex            lock; /* lock GPIOs operations. */
  48         int                     num_gpios;
  49         struct gpio_desc        **gpios;
  50         int                     num_speed;
  51         struct gpio_fan_speed   *speed;
  52         int                     speed_index;
  53 #ifdef CONFIG_PM_SLEEP
  54         int                     resume_speed;
  55 #endif
  56         bool                    pwm_enable;
  57         struct gpio_desc        *alarm_gpio;
  58         struct work_struct      alarm_work;
  59 };
  60
  61 /*
  62  * Alarm GPIO.
  63  */
  64
  65 static void fan_alarm_notify(struct work_struct *ws)
  66 {
  67         struct gpio_fan_data *fan_data =
  68                 container_of(ws, struct gpio_fan_data, alarm_work);
  69
  70         sysfs_notify(&fan_data->dev->kobj, NULL, "fan1_alarm");
  71         kobject_uevent(&fan_data->dev->kobj, KOBJ_CHANGE);
  72 }
  73
  74 static irqreturn_t fan_alarm_irq_handler(int irq, void *dev_id)
  75 {
  76         struct gpio_fan_data *fan_data = dev_id;
  77
  78         schedule_work(&fan_data->alarm_work);
  79
  80         return IRQ_NONE;
  81 }
  82
  83 static ssize_t fan1_alarm_show(struct device *dev,
  84                                struct device_attribute *attr, char *buf)
  85 {
  86         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
  87
  88         return sprintf(buf, "%d\n",
  89                        gpiod_get_value_cansleep(fan_data->alarm_gpio));
  90 }
  91
  92 static DEVICE_ATTR_RO(fan1_alarm);
  93
  94 static int fan_alarm_init(struct gpio_fan_data *fan_data)
  95 {
  96         int alarm_irq;
  97         struct device *dev = fan_data->dev;
  98
  99         /*
 100          * If the alarm GPIO don't support interrupts, just leave
 101          * without initializing the fail notification support.
 102          */
 103         alarm_irq = gpiod_to_irq(fan_data->alarm_gpio);
 104         if (alarm_irq <= 0)
 105                 return 0;
 106
 107         INIT_WORK(&fan_data->alarm_work, fan_alarm_notify);
 108         irq_set_irq_type(alarm_irq, IRQ_TYPE_EDGE_BOTH);
 109         return devm_request_irq(dev, alarm_irq, fan_alarm_irq_handler,
 110                                 IRQF_SHARED, "GPIO fan alarm", fan_data);
 111 }
 112
 113 /*
 114  * Control GPIOs.
 115  */
 116
 117 /* Must be called with fan_data->lock held, except during initialization. */
 118 static void __set_fan_ctrl(struct gpio_fan_data *fan_data, int ctrl_val)
 119 {
 120         int i;
 121
 122         for (i = 0; i < fan_data->num_gpios; i++)
 123                 gpiod_set_value_cansleep(fan_data->gpios[i],
 124                                          (ctrl_val >> i) & 1);
 125 }
 126
 127 static int __get_fan_ctrl(struct gpio_fan_data *fan_data)
 128 {
 129         int i;
 130         int ctrl_val = 0;
 131
 132         for (i = 0; i < fan_data->num_gpios; i++) {
 133                 int value;
 134
 135                 value = gpiod_get_value_cansleep(fan_data->gpios[i]);
 136                 ctrl_val |= (value << i);
 137         }
 138         return ctrl_val;
 139 }
 140
 141 /* Must be called with fan_data->lock held, except during initialization. */
 142 static void set_fan_speed(struct gpio_fan_data *fan_data, int speed_index)
 143 {
 144         if (fan_data->speed_index == speed_index)
 145                 return;
 146
 147         __set_fan_ctrl(fan_data, fan_data->speed[speed_index].ctrl_val);
 148         fan_data->speed_index = speed_index;
 149 }
 150
 151 static int get_fan_speed_index(struct gpio_fan_data *fan_data)
 152 {
 153         int ctrl_val = __get_fan_ctrl(fan_data);
 154         int i;
 155
 156         for (i = 0; i < fan_data->num_speed; i++)
 157                 if (fan_data->speed[i].ctrl_val == ctrl_val)
 158                         return i;
 159
 160         dev_warn(fan_data->dev,
 161                  "missing speed array entry for GPIO value 0x%x\n", ctrl_val);
 162
 163         return -ENODEV;
 164 }
 165
 166 static int rpm_to_speed_index(struct gpio_fan_data *fan_data, unsigned long rpm)
 167 {
 168         struct gpio_fan_speed *speed = fan_data->speed;
 169         int i;
 170
 171         for (i = 0; i < fan_data->num_speed; i++)
 172                 if (speed[i].rpm >= rpm)
 173                         return i;
 174
 175         return fan_data->num_speed - 1;
 176 }
 177
 178 static ssize_t pwm1_show(struct device *dev, struct device_attribute *attr,
 179                          char *buf)
 180 {
 181         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 182         u8 pwm = fan_data->speed_index * 255 / (fan_data->num_speed - 1);
 183
 184         return sprintf(buf, "%d\n", pwm);
 185 }
 186
 187 static ssize_t pwm1_store(struct device *dev, struct device_attribute *attr,
 188                           const char *buf, size_t count)
 189 {
 190         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 191         unsigned long pwm;
 192         int speed_index;
 193         int ret = count;
 194
 195         if (kstrtoul(buf, 10, &pwm) || pwm > 255)
 196                 return -EINVAL;
 197
 198         mutex_lock(&fan_data->lock);
 199
 200         if (!fan_data->pwm_enable) {
 201                 ret = -EPERM;
 202                 goto exit_unlock;
 203         }
 204
 205         speed_index = DIV_ROUND_UP(pwm * (fan_data->num_speed - 1), 255);
 206         set_fan_speed(fan_data, speed_index);
 207
 208 exit_unlock:
 209         mutex_unlock(&fan_data->lock);
 210
 211         return ret;
 212 }
 213
 214 static ssize_t pwm1_enable_show(struct device *dev,
 215                                 struct device_attribute *attr, char *buf)
 216 {
 217         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 218
 219         return sprintf(buf, "%d\n", fan_data->pwm_enable);
 220 }
 221
 222 static ssize_t pwm1_enable_store(struct device *dev,
 223                                  struct device_attribute *attr,
 224                                  const char *buf, size_t count)
 225 {
 226         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 227         unsigned long val;
 228
 229         if (kstrtoul(buf, 10, &val) || val > 1)
 230                 return -EINVAL;
 231
 232         if (fan_data->pwm_enable == val)
 233                 return count;
 234
 235         mutex_lock(&fan_data->lock);
 236
 237         fan_data->pwm_enable = val;
 238
 239         /* Disable manual control mode: set fan at full speed. */
 240         if (val == 0)
 241                 set_fan_speed(fan_data, fan_data->num_speed - 1);
 242
 243         mutex_unlock(&fan_data->lock);
 244
 245         return count;
 246 }
 247
 248 static ssize_t pwm1_mode_show(struct device *dev,
 249                               struct device_attribute *attr, char *buf)
 250 {
 251         return sprintf(buf, "0\n");
 252 }
 253
 254 static ssize_t fan1_min_show(struct device *dev,
 255                              struct device_attribute *attr, char *buf)
 256 {
 257         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 258
 259         return sprintf(buf, "%d\n", fan_data->speed[0].rpm);
 260 }
 261
 262 static ssize_t fan1_max_show(struct device *dev,
 263                              struct device_attribute *attr, char *buf)
 264 {
 265         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 266
 267         return sprintf(buf, "%d\n",
 268                        fan_data->speed[fan_data->num_speed - 1].rpm);
 269 }
 270
 271 static ssize_t fan1_input_show(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", fan_data->speed[fan_data->speed_index].rpm);
 277 }
 278
 279 static ssize_t set_rpm(struct device *dev, struct device_attribute *attr,
 280                        const char *buf, size_t count)
 281 {
 282         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 283         unsigned long rpm;
 284         int ret = count;
 285
 286         if (kstrtoul(buf, 10, &rpm))
 287                 return -EINVAL;
 288
 289         mutex_lock(&fan_data->lock);
 290
 291         if (!fan_data->pwm_enable) {
 292                 ret = -EPERM;
 293                 goto exit_unlock;
 294         }
 295
 296         set_fan_speed(fan_data, rpm_to_speed_index(fan_data, rpm));
 297
 298 exit_unlock:
 299         mutex_unlock(&fan_data->lock);
 300
 301         return ret;
 302 }
 303
 304 static DEVICE_ATTR_RW(pwm1);
 305 static DEVICE_ATTR_RW(pwm1_enable);
 306 static DEVICE_ATTR_RO(pwm1_mode);
 307 static DEVICE_ATTR_RO(fan1_min);
 308 static DEVICE_ATTR_RO(fan1_max);
 309 static DEVICE_ATTR_RO(fan1_input);
 310 static DEVICE_ATTR(fan1_target, S_IRUGO | S_IWUSR, fan1_input_show, set_rpm);
 311
 312 static umode_t gpio_fan_is_visible(struct kobject *kobj,
 313                                    struct attribute *attr, int index)
 314 {
 315         struct device *dev = container_of(kobj, struct device, kobj);
 316         struct gpio_fan_data *data = dev_get_drvdata(dev);
 317
 318         if (index == 0 && !data->alarm_gpio)
 319                 return 0;
 320         if (index > 0 && !data->gpios)
 321                 return 0;
 322
 323         return attr->mode;
 324 }
 325
 326 static struct attribute *gpio_fan_attributes[] = {
 327         &dev_attr_fan1_alarm.attr,              /* 0 */
 328         &dev_attr_pwm1.attr,                    /* 1 */
 329         &dev_attr_pwm1_enable.attr,
 330         &dev_attr_pwm1_mode.attr,
 331         &dev_attr_fan1_input.attr,
 332         &dev_attr_fan1_target.attr,
 333         &dev_attr_fan1_min.attr,
 334         &dev_attr_fan1_max.attr,
 335         NULL
 336 };
 337
 338 static const struct attribute_group gpio_fan_group = {
 339         .attrs = gpio_fan_attributes,
 340         .is_visible = gpio_fan_is_visible,
 341 };
 342
 343 static const struct attribute_group *gpio_fan_groups[] = {
 344         &gpio_fan_group,
 345         NULL
 346 };
 347
 348 static int fan_ctrl_init(struct gpio_fan_data *fan_data)
 349 {
 350         int num_gpios = fan_data->num_gpios;
 351         struct gpio_desc **gpios = fan_data->gpios;
 352         int i, err;
 353
 354         for (i = 0; i < num_gpios; i++) {
 355                 /*
 356                  * The GPIO descriptors were retrieved with GPIOD_ASIS so here
 357                  * we set the GPIO into output mode, carefully preserving the
 358                  * current value by setting it to whatever it is already set
 359                  * (no surprise changes in default fan speed).
 360                  */
 361                 err = gpiod_direction_output(gpios[i],
 362                                         gpiod_get_value_cansleep(gpios[i]));
 363                 if (err)
 364                         return err;
 365         }
 366
 367         fan_data->pwm_enable = true; /* Enable manual fan speed control. */
 368         fan_data->speed_index = get_fan_speed_index(fan_data);
 369         if (fan_data->speed_index < 0)
 370                 return fan_data->speed_index;
 371
 372         return 0;
 373 }
 374
 375 static int gpio_fan_get_max_state(struct thermal_cooling_device *cdev,
 376                                   unsigned long *state)
 377 {
 378         struct gpio_fan_data *fan_data = cdev->devdata;
 379
 380         if (!fan_data)
 381                 return -EINVAL;
 382
 383         *state = fan_data->num_speed - 1;
 384         return 0;
 385 }
 386
 387 static int gpio_fan_get_cur_state(struct thermal_cooling_device *cdev,
 388                                   unsigned long *state)
 389 {
 390         struct gpio_fan_data *fan_data = cdev->devdata;
 391
 392         if (!fan_data)
 393                 return -EINVAL;
 394
 395         *state = fan_data->speed_index;
 396         return 0;
 397 }
 398
 399 static int gpio_fan_set_cur_state(struct thermal_cooling_device *cdev,
 400                                   unsigned long state)
 401 {
 402         struct gpio_fan_data *fan_data = cdev->devdata;
 403
 404         if (!fan_data)
 405                 return -EINVAL;
 406
 407         set_fan_speed(fan_data, state);
 408         return 0;
 409 }
 410
 411 static const struct thermal_cooling_device_ops gpio_fan_cool_ops = {
 412         .get_max_state = gpio_fan_get_max_state,
 413         .get_cur_state = gpio_fan_get_cur_state,
 414         .set_cur_state = gpio_fan_set_cur_state,
 415 };
 416
 417 /*
 418  * Translate OpenFirmware node properties into platform_data
 419  */
 420 static int gpio_fan_get_of_data(struct gpio_fan_data *fan_data)
 421 {
 422         struct gpio_fan_speed *speed;
 423         struct device *dev = fan_data->dev;
 424         struct device_node *np = dev->of_node;
 425         struct gpio_desc **gpios;
 426         unsigned i;
 427         u32 u;
 428         struct property *prop;
 429         const __be32 *p;
 430
 431         /* Alarm GPIO if one exists */
 432         fan_data->alarm_gpio = devm_gpiod_get_optional(dev, "alarm", GPIOD_IN);
 433         if (IS_ERR(fan_data->alarm_gpio))
 434                 return PTR_ERR(fan_data->alarm_gpio);
 435
 436         /* Fill GPIO pin array */
 437         fan_data->num_gpios = gpiod_count(dev, NULL);
 438         if (fan_data->num_gpios <= 0) {
 439                 if (fan_data->alarm_gpio)
 440                         return 0;
 441                 dev_err(dev, "DT properties empty / missing");
 442                 return -ENODEV;
 443         }
 444         gpios = devm_kcalloc(dev,
 445                              fan_data->num_gpios, sizeof(struct gpio_desc *),
 446                              GFP_KERNEL);
 447         if (!gpios)
 448                 return -ENOMEM;
 449         for (i = 0; i < fan_data->num_gpios; i++) {
 450                 gpios[i] = devm_gpiod_get_index(dev, NULL, i, GPIOD_ASIS);
 451                 if (IS_ERR(gpios[i]))
 452                         return PTR_ERR(gpios[i]);
 453         }
 454         fan_data->gpios = gpios;
 455
 456         /* Get number of RPM/ctrl_val pairs in speed map */
 457         prop = of_find_property(np, "gpio-fan,speed-map", &i);
 458         if (!prop) {
 459                 dev_err(dev, "gpio-fan,speed-map DT property missing");
 460                 return -ENODEV;
 461         }
 462         i = i / sizeof(u32);
 463         if (i == 0 || i & 1) {
 464                 dev_err(dev, "gpio-fan,speed-map contains zero/odd number of entries");
 465                 return -ENODEV;
 466         }
 467         fan_data->num_speed = i / 2;
 468
 469         /*
 470          * Populate speed map
 471          * Speed map is in the form <RPM ctrl_val RPM ctrl_val ...>
 472          * this needs splitting into pairs to create gpio_fan_speed structs
 473          */
 474         speed = devm_kcalloc(dev,
 475                         fan_data->num_speed, sizeof(struct gpio_fan_speed),
 476                         GFP_KERNEL);
 477         if (!speed)
 478                 return -ENOMEM;
 479         p = NULL;
 480         for (i = 0; i < fan_data->num_speed; i++) {
 481                 p = of_prop_next_u32(prop, p, &u);
 482                 if (!p)
 483                         return -ENODEV;
 484                 speed[i].rpm = u;
 485                 p = of_prop_next_u32(prop, p, &u);
 486                 if (!p)
 487                         return -ENODEV;
 488                 speed[i].ctrl_val = u;
 489         }
 490         fan_data->speed = speed;
 491
 492         return 0;
 493 }
 494
 495 static const struct of_device_id of_gpio_fan_match[] = {
 496         { .compatible = "gpio-fan", },
 497         {},
 498 };
 499 MODULE_DEVICE_TABLE(of, of_gpio_fan_match);
 500
 501 static int gpio_fan_probe(struct platform_device *pdev)
 502 {
 503         int err;
 504         struct gpio_fan_data *fan_data;
 505         struct device *dev = &pdev->dev;
 506         struct device_node *np = dev->of_node;
 507
 508         fan_data = devm_kzalloc(dev, sizeof(struct gpio_fan_data),
 509                                 GFP_KERNEL);
 510         if (!fan_data)
 511                 return -ENOMEM;
 512
 513         fan_data->dev = dev;
 514         err = gpio_fan_get_of_data(fan_data);
 515         if (err)
 516                 return err;
 517
 518         platform_set_drvdata(pdev, fan_data);
 519         mutex_init(&fan_data->lock);
 520
 521         /* Configure alarm GPIO if available. */
 522         if (fan_data->alarm_gpio) {
 523                 err = fan_alarm_init(fan_data);
 524                 if (err)
 525                         return err;
 526         }
 527
 528         /* Configure control GPIOs if available. */
 529         if (fan_data->gpios && fan_data->num_gpios > 0) {
 530                 if (!fan_data->speed || fan_data->num_speed <= 1)
 531                         return -EINVAL;
 532                 err = fan_ctrl_init(fan_data);
 533                 if (err)
 534                         return err;
 535         }
 536
 537         /* Make this driver part of hwmon class. */
 538         fan_data->hwmon_dev =
 539                 devm_hwmon_device_register_with_groups(dev,
 540                                                        "gpio_fan", fan_data,
 541                                                        gpio_fan_groups);
 542         if (IS_ERR(fan_data->hwmon_dev))
 543                 return PTR_ERR(fan_data->hwmon_dev);
 544
 545         /* Optional cooling device register for Device tree platforms */
 546         fan_data->cdev = thermal_of_cooling_device_register(np,
 547                                                             "gpio-fan",
 548                                                             fan_data,
 549                                                             &gpio_fan_cool_ops);
 550
 551         dev_info(dev, "GPIO fan initialized\n");
 552
 553         return 0;
 554 }
 555
 556 static int gpio_fan_remove(struct platform_device *pdev)
 557 {
 558         struct gpio_fan_data *fan_data = platform_get_drvdata(pdev);
 559
 560         if (!IS_ERR(fan_data->cdev))
 561                 thermal_cooling_device_unregister(fan_data->cdev);
 562
 563         if (fan_data->gpios)
 564                 set_fan_speed(fan_data, 0);
 565
 566         return 0;
 567 }
 568
 569 static void gpio_fan_shutdown(struct platform_device *pdev)
 570 {
 571         gpio_fan_remove(pdev);
 572 }
 573
 574 #ifdef CONFIG_PM_SLEEP
 575 static int gpio_fan_suspend(struct device *dev)
 576 {
 577         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 578
 579         if (fan_data->gpios) {
 580                 fan_data->resume_speed = fan_data->speed_index;
 581                 set_fan_speed(fan_data, 0);
 582         }
 583
 584         return 0;
 585 }
 586
 587 static int gpio_fan_resume(struct device *dev)
 588 {
 589         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 590
 591         if (fan_data->gpios)
 592                 set_fan_speed(fan_data, fan_data->resume_speed);
 593
 594         return 0;
 595 }
 596
 597 static SIMPLE_DEV_PM_OPS(gpio_fan_pm, gpio_fan_suspend, gpio_fan_resume);
 598 #define GPIO_FAN_PM     (&gpio_fan_pm)
 599 #else
 600 #define GPIO_FAN_PM     NULL
 601 #endif
 602
 603 static struct platform_driver gpio_fan_driver = {
 604         .probe          = gpio_fan_probe,
 605         .remove         = gpio_fan_remove,
 606         .shutdown       = gpio_fan_shutdown,
 607         .driver = {
 608                 .name   = "gpio-fan",
 609                 .pm     = GPIO_FAN_PM,
 610                 .of_match_table = of_match_ptr(of_gpio_fan_match),
 611         },
 612 };
 613
 614 module_platform_driver(gpio_fan_driver);
 615
 616 MODULE_AUTHOR("Simon Guinot <sguinot@lacie.com>");
 617 MODULE_DESCRIPTION("GPIO FAN driver");
 618 MODULE_LICENSE("GPL");
 619 MODULE_ALIAS("platform:gpio-fan");