drivers/hwmon/gpio-fan.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * gpio-fan.c - Hwmon driver for fans connected to GPIO lines.
   4  *
   5  * Copyright (C) 2010 LaCie
   6  *
   7  * Author: Simon Guinot <sguinot@lacie.com>
   8  */
   9
  10 #include <linux/module.h>
  11 #include <linux/init.h>
  12 #include <linux/slab.h>
  13 #include <linux/interrupt.h>
  14 #include <linux/irq.h>
  15 #include <linux/platform_device.h>
  16 #include <linux/err.h>
  17 #include <linux/mutex.h>
  18 #include <linux/hwmon.h>
  19 #include <linux/gpio/consumer.h>
  20 #include <linux/of.h>
  21 #include <linux/of_platform.h>
  22 #include <linux/thermal.h>
  23
  24 struct gpio_fan_speed {
  25         int rpm;
  26         int ctrl_val;
  27 };
  28
  29 struct gpio_fan_data {
  30         struct device           *dev;
  31         struct device           *hwmon_dev;
  32         /* Cooling device if any */
  33         struct thermal_cooling_device *cdev;
  34         struct mutex            lock; /* lock GPIOs operations. */
  35         int                     num_gpios;
  36         struct gpio_desc        **gpios;
  37         int                     num_speed;
  38         struct gpio_fan_speed   *speed;
  39         int                     speed_index;
  40 #ifdef CONFIG_PM_SLEEP
  41         int                     resume_speed;
  42 #endif
  43         bool                    pwm_enable;
  44         struct gpio_desc        *alarm_gpio;
  45         struct work_struct      alarm_work;
  46 };
  47
  48 /*
  49  * Alarm GPIO.
  50  */
  51
  52 static void fan_alarm_notify(struct work_struct *ws)
  53 {
  54         struct gpio_fan_data *fan_data =
  55                 container_of(ws, struct gpio_fan_data, alarm_work);
  56
  57         sysfs_notify(&fan_data->hwmon_dev->kobj, NULL, "fan1_alarm");
  58         kobject_uevent(&fan_data->hwmon_dev->kobj, KOBJ_CHANGE);
  59 }
  60
  61 static irqreturn_t fan_alarm_irq_handler(int irq, void *dev_id)
  62 {
  63         struct gpio_fan_data *fan_data = dev_id;
  64
  65         schedule_work(&fan_data->alarm_work);
  66
  67         return IRQ_NONE;
  68 }
  69
  70 static ssize_t fan1_alarm_show(struct device *dev,
  71                                struct device_attribute *attr, char *buf)
  72 {
  73         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
  74
  75         return sprintf(buf, "%d\n",
  76                        gpiod_get_value_cansleep(fan_data->alarm_gpio));
  77 }
  78
  79 static DEVICE_ATTR_RO(fan1_alarm);
  80
  81 static int fan_alarm_init(struct gpio_fan_data *fan_data)
  82 {
  83         int alarm_irq;
  84         struct device *dev = fan_data->dev;
  85
  86         /*
  87          * If the alarm GPIO don't support interrupts, just leave
  88          * without initializing the fail notification support.
  89          */
  90         alarm_irq = gpiod_to_irq(fan_data->alarm_gpio);
  91         if (alarm_irq <= 0)
  92                 return 0;
  93
  94         INIT_WORK(&fan_data->alarm_work, fan_alarm_notify);
  95         irq_set_irq_type(alarm_irq, IRQ_TYPE_EDGE_BOTH);
  96         return devm_request_irq(dev, alarm_irq, fan_alarm_irq_handler,
  97                                 IRQF_SHARED, "GPIO fan alarm", fan_data);
  98 }
  99
 100 /*
 101  * Control GPIOs.
 102  */
 103
 104 /* Must be called with fan_data->lock held, except during initialization. */
 105 static void __set_fan_ctrl(struct gpio_fan_data *fan_data, int ctrl_val)
 106 {
 107         int i;
 108
 109         for (i = 0; i < fan_data->num_gpios; i++)
 110                 gpiod_set_value_cansleep(fan_data->gpios[i],
 111                                          (ctrl_val >> i) & 1);
 112 }
 113
 114 static int __get_fan_ctrl(struct gpio_fan_data *fan_data)
 115 {
 116         int i;
 117         int ctrl_val = 0;
 118
 119         for (i = 0; i < fan_data->num_gpios; i++) {
 120                 int value;
 121
 122                 value = gpiod_get_value_cansleep(fan_data->gpios[i]);
 123                 ctrl_val |= (value << i);
 124         }
 125         return ctrl_val;
 126 }
 127
 128 /* Must be called with fan_data->lock held, except during initialization. */
 129 static void set_fan_speed(struct gpio_fan_data *fan_data, int speed_index)
 130 {
 131         if (fan_data->speed_index == speed_index)
 132                 return;
 133
 134         __set_fan_ctrl(fan_data, fan_data->speed[speed_index].ctrl_val);
 135         fan_data->speed_index = speed_index;
 136 }
 137
 138 static int get_fan_speed_index(struct gpio_fan_data *fan_data)
 139 {
 140         int ctrl_val = __get_fan_ctrl(fan_data);
 141         int i;
 142
 143         for (i = 0; i < fan_data->num_speed; i++)
 144                 if (fan_data->speed[i].ctrl_val == ctrl_val)
 145                         return i;
 146
 147         dev_warn(fan_data->dev,
 148                  "missing speed array entry for GPIO value 0x%x\n", ctrl_val);
 149
 150         return -ENODEV;
 151 }
 152
 153 static int rpm_to_speed_index(struct gpio_fan_data *fan_data, unsigned long rpm)
 154 {
 155         struct gpio_fan_speed *speed = fan_data->speed;
 156         int i;
 157
 158         for (i = 0; i < fan_data->num_speed; i++)
 159                 if (speed[i].rpm >= rpm)
 160                         return i;
 161
 162         return fan_data->num_speed - 1;
 163 }
 164
 165 static ssize_t pwm1_show(struct device *dev, struct device_attribute *attr,
 166                          char *buf)
 167 {
 168         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 169         u8 pwm = fan_data->speed_index * 255 / (fan_data->num_speed - 1);
 170
 171         return sprintf(buf, "%d\n", pwm);
 172 }
 173
 174 static ssize_t pwm1_store(struct device *dev, struct device_attribute *attr,
 175                           const char *buf, size_t count)
 176 {
 177         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 178         unsigned long pwm;
 179         int speed_index;
 180         int ret = count;
 181
 182         if (kstrtoul(buf, 10, &pwm) || pwm > 255)
 183                 return -EINVAL;
 184
 185         mutex_lock(&fan_data->lock);
 186
 187         if (!fan_data->pwm_enable) {
 188                 ret = -EPERM;
 189                 goto exit_unlock;
 190         }
 191
 192         speed_index = DIV_ROUND_UP(pwm * (fan_data->num_speed - 1), 255);
 193         set_fan_speed(fan_data, speed_index);
 194
 195 exit_unlock:
 196         mutex_unlock(&fan_data->lock);
 197
 198         return ret;
 199 }
 200
 201 static ssize_t pwm1_enable_show(struct device *dev,
 202                                 struct device_attribute *attr, char *buf)
 203 {
 204         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 205
 206         return sprintf(buf, "%d\n", fan_data->pwm_enable);
 207 }
 208
 209 static ssize_t pwm1_enable_store(struct device *dev,
 210                                  struct device_attribute *attr,
 211                                  const char *buf, size_t count)
 212 {
 213         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 214         unsigned long val;
 215
 216         if (kstrtoul(buf, 10, &val) || val > 1)
 217                 return -EINVAL;
 218
 219         if (fan_data->pwm_enable == val)
 220                 return count;
 221
 222         mutex_lock(&fan_data->lock);
 223
 224         fan_data->pwm_enable = val;
 225
 226         /* Disable manual control mode: set fan at full speed. */
 227         if (val == 0)
 228                 set_fan_speed(fan_data, fan_data->num_speed - 1);
 229
 230         mutex_unlock(&fan_data->lock);
 231
 232         return count;
 233 }
 234
 235 static ssize_t pwm1_mode_show(struct device *dev,
 236                               struct device_attribute *attr, char *buf)
 237 {
 238         return sprintf(buf, "0\n");
 239 }
 240
 241 static ssize_t fan1_min_show(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->speed[0].rpm);
 247 }
 248
 249 static ssize_t fan1_max_show(struct device *dev,
 250                              struct device_attribute *attr, char *buf)
 251 {
 252         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 253
 254         return sprintf(buf, "%d\n",
 255                        fan_data->speed[fan_data->num_speed - 1].rpm);
 256 }
 257
 258 static ssize_t fan1_input_show(struct device *dev,
 259                                struct device_attribute *attr, char *buf)
 260 {
 261         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 262
 263         return sprintf(buf, "%d\n", fan_data->speed[fan_data->speed_index].rpm);
 264 }
 265
 266 static ssize_t set_rpm(struct device *dev, struct device_attribute *attr,
 267                        const char *buf, size_t count)
 268 {
 269         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 270         unsigned long rpm;
 271         int ret = count;
 272
 273         if (kstrtoul(buf, 10, &rpm))
 274                 return -EINVAL;
 275
 276         mutex_lock(&fan_data->lock);
 277
 278         if (!fan_data->pwm_enable) {
 279                 ret = -EPERM;
 280                 goto exit_unlock;
 281         }
 282
 283         set_fan_speed(fan_data, rpm_to_speed_index(fan_data, rpm));
 284
 285 exit_unlock:
 286         mutex_unlock(&fan_data->lock);
 287
 288         return ret;
 289 }
 290
 291 static DEVICE_ATTR_RW(pwm1);
 292 static DEVICE_ATTR_RW(pwm1_enable);
 293 static DEVICE_ATTR_RO(pwm1_mode);
 294 static DEVICE_ATTR_RO(fan1_min);
 295 static DEVICE_ATTR_RO(fan1_max);
 296 static DEVICE_ATTR_RO(fan1_input);
 297 static DEVICE_ATTR(fan1_target, 0644, fan1_input_show, set_rpm);
 298
 299 static umode_t gpio_fan_is_visible(struct kobject *kobj,
 300                                    struct attribute *attr, int index)
 301 {
 302         struct device *dev = container_of(kobj, struct device, kobj);
 303         struct gpio_fan_data *data = dev_get_drvdata(dev);
 304
 305         if (index == 0 && !data->alarm_gpio)
 306                 return 0;
 307         if (index > 0 && !data->gpios)
 308                 return 0;
 309
 310         return attr->mode;
 311 }
 312
 313 static struct attribute *gpio_fan_attributes[] = {
 314         &dev_attr_fan1_alarm.attr,              /* 0 */
 315         &dev_attr_pwm1.attr,                    /* 1 */
 316         &dev_attr_pwm1_enable.attr,
 317         &dev_attr_pwm1_mode.attr,
 318         &dev_attr_fan1_input.attr,
 319         &dev_attr_fan1_target.attr,
 320         &dev_attr_fan1_min.attr,
 321         &dev_attr_fan1_max.attr,
 322         NULL
 323 };
 324
 325 static const struct attribute_group gpio_fan_group = {
 326         .attrs = gpio_fan_attributes,
 327         .is_visible = gpio_fan_is_visible,
 328 };
 329
 330 static const struct attribute_group *gpio_fan_groups[] = {
 331         &gpio_fan_group,
 332         NULL
 333 };
 334
 335 static int fan_ctrl_init(struct gpio_fan_data *fan_data)
 336 {
 337         int num_gpios = fan_data->num_gpios;
 338         struct gpio_desc **gpios = fan_data->gpios;
 339         int i, err;
 340
 341         for (i = 0; i < num_gpios; i++) {
 342                 /*
 343                  * The GPIO descriptors were retrieved with GPIOD_ASIS so here
 344                  * we set the GPIO into output mode, carefully preserving the
 345                  * current value by setting it to whatever it is already set
 346                  * (no surprise changes in default fan speed).
 347                  */
 348                 err = gpiod_direction_output(gpios[i],
 349                                         gpiod_get_value_cansleep(gpios[i]));
 350                 if (err)
 351                         return err;
 352         }
 353
 354         fan_data->pwm_enable = true; /* Enable manual fan speed control. */
 355         fan_data->speed_index = get_fan_speed_index(fan_data);
 356         if (fan_data->speed_index < 0)
 357                 return fan_data->speed_index;
 358
 359         return 0;
 360 }
 361
 362 static int gpio_fan_get_max_state(struct thermal_cooling_device *cdev,
 363                                   unsigned long *state)
 364 {
 365         struct gpio_fan_data *fan_data = cdev->devdata;
 366
 367         if (!fan_data)
 368                 return -EINVAL;
 369
 370         *state = fan_data->num_speed - 1;
 371         return 0;
 372 }
 373
 374 static int gpio_fan_get_cur_state(struct thermal_cooling_device *cdev,
 375                                   unsigned long *state)
 376 {
 377         struct gpio_fan_data *fan_data = cdev->devdata;
 378
 379         if (!fan_data)
 380                 return -EINVAL;
 381
 382         *state = fan_data->speed_index;
 383         return 0;
 384 }
 385
 386 static int gpio_fan_set_cur_state(struct thermal_cooling_device *cdev,
 387                                   unsigned long state)
 388 {
 389         struct gpio_fan_data *fan_data = cdev->devdata;
 390
 391         if (!fan_data)
 392                 return -EINVAL;
 393
 394         set_fan_speed(fan_data, state);
 395         return 0;
 396 }
 397
 398 static const struct thermal_cooling_device_ops gpio_fan_cool_ops = {
 399         .get_max_state = gpio_fan_get_max_state,
 400         .get_cur_state = gpio_fan_get_cur_state,
 401         .set_cur_state = gpio_fan_set_cur_state,
 402 };
 403
 404 /*
 405  * Translate OpenFirmware node properties into platform_data
 406  */
 407 static int gpio_fan_get_of_data(struct gpio_fan_data *fan_data)
 408 {
 409         struct gpio_fan_speed *speed;
 410         struct device *dev = fan_data->dev;
 411         struct device_node *np = dev->of_node;
 412         struct gpio_desc **gpios;
 413         unsigned i;
 414         u32 u;
 415         struct property *prop;
 416         const __be32 *p;
 417
 418         /* Alarm GPIO if one exists */
 419         fan_data->alarm_gpio = devm_gpiod_get_optional(dev, "alarm", GPIOD_IN);
 420         if (IS_ERR(fan_data->alarm_gpio))
 421                 return PTR_ERR(fan_data->alarm_gpio);
 422
 423         /* Fill GPIO pin array */
 424         fan_data->num_gpios = gpiod_count(dev, NULL);
 425         if (fan_data->num_gpios <= 0) {
 426                 if (fan_data->alarm_gpio)
 427                         return 0;
 428                 dev_err(dev, "DT properties empty / missing");
 429                 return -ENODEV;
 430         }
 431         gpios = devm_kcalloc(dev,
 432                              fan_data->num_gpios, sizeof(struct gpio_desc *),
 433                              GFP_KERNEL);
 434         if (!gpios)
 435                 return -ENOMEM;
 436         for (i = 0; i < fan_data->num_gpios; i++) {
 437                 gpios[i] = devm_gpiod_get_index(dev, NULL, i, GPIOD_ASIS);
 438                 if (IS_ERR(gpios[i]))
 439                         return PTR_ERR(gpios[i]);
 440         }
 441         fan_data->gpios = gpios;
 442
 443         /* Get number of RPM/ctrl_val pairs in speed map */
 444         prop = of_find_property(np, "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         fan_data->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_kcalloc(dev,
 462                         fan_data->num_speed, sizeof(struct gpio_fan_speed),
 463                         GFP_KERNEL);
 464         if (!speed)
 465                 return -ENOMEM;
 466         p = NULL;
 467         for (i = 0; i < fan_data->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         fan_data->speed = speed;
 478
 479         return 0;
 480 }
 481
 482 static const struct of_device_id of_gpio_fan_match[] = {
 483         { .compatible = "gpio-fan", },
 484         {},
 485 };
 486 MODULE_DEVICE_TABLE(of, of_gpio_fan_match);
 487
 488 static void gpio_fan_stop(void *data)
 489 {
 490         set_fan_speed(data, 0);
 491 }
 492
 493 static int gpio_fan_probe(struct platform_device *pdev)
 494 {
 495         int err;
 496         struct gpio_fan_data *fan_data;
 497         struct device *dev = &pdev->dev;
 498         struct device_node *np = dev->of_node;
 499
 500         fan_data = devm_kzalloc(dev, sizeof(struct gpio_fan_data),
 501                                 GFP_KERNEL);
 502         if (!fan_data)
 503                 return -ENOMEM;
 504
 505         fan_data->dev = dev;
 506         err = gpio_fan_get_of_data(fan_data);
 507         if (err)
 508                 return err;
 509
 510         platform_set_drvdata(pdev, fan_data);
 511         mutex_init(&fan_data->lock);
 512
 513         /* Configure control GPIOs if available. */
 514         if (fan_data->gpios && fan_data->num_gpios > 0) {
 515                 if (!fan_data->speed || fan_data->num_speed <= 1)
 516                         return -EINVAL;
 517                 err = fan_ctrl_init(fan_data);
 518                 if (err)
 519                         return err;
 520                 err = devm_add_action_or_reset(dev, gpio_fan_stop, fan_data);
 521                 if (err)
 522                         return err;
 523         }
 524
 525         /* Make this driver part of hwmon class. */
 526         fan_data->hwmon_dev =
 527                 devm_hwmon_device_register_with_groups(dev,
 528                                                        "gpio_fan", fan_data,
 529                                                        gpio_fan_groups);
 530         if (IS_ERR(fan_data->hwmon_dev))
 531                 return PTR_ERR(fan_data->hwmon_dev);
 532
 533         /* Configure alarm GPIO if available. */
 534         if (fan_data->alarm_gpio) {
 535                 err = fan_alarm_init(fan_data);
 536                 if (err)
 537                         return err;
 538         }
 539
 540         /* Optional cooling device register for Device tree platforms */
 541         fan_data->cdev = devm_thermal_of_cooling_device_register(dev, np,
 542                                 "gpio-fan", fan_data, &gpio_fan_cool_ops);
 543
 544         dev_info(dev, "GPIO fan initialized\n");
 545
 546         return 0;
 547 }
 548
 549 static void gpio_fan_shutdown(struct platform_device *pdev)
 550 {
 551         struct gpio_fan_data *fan_data = platform_get_drvdata(pdev);
 552
 553         if (fan_data->gpios)
 554                 set_fan_speed(fan_data, 0);
 555 }
 556
 557 #ifdef CONFIG_PM_SLEEP
 558 static int gpio_fan_suspend(struct device *dev)
 559 {
 560         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 561
 562         if (fan_data->gpios) {
 563                 fan_data->resume_speed = fan_data->speed_index;
 564                 set_fan_speed(fan_data, 0);
 565         }
 566
 567         return 0;
 568 }
 569
 570 static int gpio_fan_resume(struct device *dev)
 571 {
 572         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 573
 574         if (fan_data->gpios)
 575                 set_fan_speed(fan_data, fan_data->resume_speed);
 576
 577         return 0;
 578 }
 579
 580 static SIMPLE_DEV_PM_OPS(gpio_fan_pm, gpio_fan_suspend, gpio_fan_resume);
 581 #define GPIO_FAN_PM     (&gpio_fan_pm)
 582 #else
 583 #define GPIO_FAN_PM     NULL
 584 #endif
 585
 586 static struct platform_driver gpio_fan_driver = {
 587         .probe          = gpio_fan_probe,
 588         .shutdown       = gpio_fan_shutdown,
 589         .driver = {
 590                 .name   = "gpio-fan",
 591                 .pm     = GPIO_FAN_PM,
 592                 .of_match_table = of_match_ptr(of_gpio_fan_match),
 593         },
 594 };
 595
 596 module_platform_driver(gpio_fan_driver);
 597
 598 MODULE_AUTHOR("Simon Guinot <sguinot@lacie.com>");
 599 MODULE_DESCRIPTION("GPIO FAN driver");
 600 MODULE_LICENSE("GPL");
 601 MODULE_ALIAS("platform:gpio-fan");