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         /*
 109          * If the alarm GPIO don't support interrupts, just leave
 110          * without initializing the fail notification support.
 111          */
 112         alarm_irq = gpio_to_irq(alarm->gpio);
 113         if (alarm_irq < 0)
 114                 return 0;
 115
 116         INIT_WORK(&fan_data->alarm_work, fan_alarm_notify);
 117         irq_set_irq_type(alarm_irq, IRQ_TYPE_EDGE_BOTH);
 118         err = devm_request_irq(&pdev->dev, alarm_irq, fan_alarm_irq_handler,
 119                                IRQF_SHARED, "GPIO fan alarm", fan_data);
 120         return err;
 121 }
 122
 123 /*
 124  * Control GPIOs.
 125  */
 126
 127 /* Must be called with fan_data->lock held, except during initialization. */
 128 static void __set_fan_ctrl(struct gpio_fan_data *fan_data, int ctrl_val)
 129 {
 130         int i;
 131
 132         for (i = 0; i < fan_data->num_ctrl; i++)
 133                 gpio_set_value(fan_data->ctrl[i], (ctrl_val >> i) & 1);
 134 }
 135
 136 static int __get_fan_ctrl(struct gpio_fan_data *fan_data)
 137 {
 138         int i;
 139         int ctrl_val = 0;
 140
 141         for (i = 0; i < fan_data->num_ctrl; i++) {
 142                 int value;
 143
 144                 value = gpio_get_value(fan_data->ctrl[i]);
 145                 ctrl_val |= (value << i);
 146         }
 147         return ctrl_val;
 148 }
 149
 150 /* Must be called with fan_data->lock held, except during initialization. */
 151 static void set_fan_speed(struct gpio_fan_data *fan_data, int speed_index)
 152 {
 153         if (fan_data->speed_index == speed_index)
 154                 return;
 155
 156         __set_fan_ctrl(fan_data, fan_data->speed[speed_index].ctrl_val);
 157         fan_data->speed_index = speed_index;
 158 }
 159
 160 static int get_fan_speed_index(struct gpio_fan_data *fan_data)
 161 {
 162         int ctrl_val = __get_fan_ctrl(fan_data);
 163         int i;
 164
 165         for (i = 0; i < fan_data->num_speed; i++)
 166                 if (fan_data->speed[i].ctrl_val == ctrl_val)
 167                         return i;
 168
 169         dev_warn(&fan_data->pdev->dev,
 170                  "missing speed array entry for GPIO value 0x%x\n", ctrl_val);
 171
 172         return -EINVAL;
 173 }
 174
 175 static int rpm_to_speed_index(struct gpio_fan_data *fan_data, int rpm)
 176 {
 177         struct gpio_fan_speed *speed = fan_data->speed;
 178         int i;
 179
 180         for (i = 0; i < fan_data->num_speed; i++)
 181                 if (speed[i].rpm >= rpm)
 182                         return i;
 183
 184         return fan_data->num_speed - 1;
 185 }
 186
 187 static ssize_t show_pwm(struct device *dev,
 188                         struct device_attribute *attr, char *buf)
 189 {
 190         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 191         u8 pwm = fan_data->speed_index * 255 / (fan_data->num_speed - 1);
 192
 193         return sprintf(buf, "%d\n", pwm);
 194 }
 195
 196 static ssize_t set_pwm(struct device *dev, struct device_attribute *attr,
 197                        const char *buf, size_t count)
 198 {
 199         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 200         unsigned long pwm;
 201         int speed_index;
 202         int ret = count;
 203
 204         if (kstrtoul(buf, 10, &pwm) || pwm > 255)
 205                 return -EINVAL;
 206
 207         mutex_lock(&fan_data->lock);
 208
 209         if (!fan_data->pwm_enable) {
 210                 ret = -EPERM;
 211                 goto exit_unlock;
 212         }
 213
 214         speed_index = DIV_ROUND_UP(pwm * (fan_data->num_speed - 1), 255);
 215         set_fan_speed(fan_data, speed_index);
 216
 217 exit_unlock:
 218         mutex_unlock(&fan_data->lock);
 219
 220         return ret;
 221 }
 222
 223 static ssize_t show_pwm_enable(struct device *dev,
 224                                struct device_attribute *attr, char *buf)
 225 {
 226         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 227
 228         return sprintf(buf, "%d\n", fan_data->pwm_enable);
 229 }
 230
 231 static ssize_t set_pwm_enable(struct device *dev, struct device_attribute *attr,
 232                               const char *buf, size_t count)
 233 {
 234         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 235         unsigned long val;
 236
 237         if (kstrtoul(buf, 10, &val) || val > 1)
 238                 return -EINVAL;
 239
 240         if (fan_data->pwm_enable == val)
 241                 return count;
 242
 243         mutex_lock(&fan_data->lock);
 244
 245         fan_data->pwm_enable = val;
 246
 247         /* Disable manual control mode: set fan at full speed. */
 248         if (val == 0)
 249                 set_fan_speed(fan_data, fan_data->num_speed - 1);
 250
 251         mutex_unlock(&fan_data->lock);
 252
 253         return count;
 254 }
 255
 256 static ssize_t show_pwm_mode(struct device *dev,
 257                              struct device_attribute *attr, char *buf)
 258 {
 259         return sprintf(buf, "0\n");
 260 }
 261
 262 static ssize_t show_rpm_min(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", fan_data->speed[0].rpm);
 268 }
 269
 270 static ssize_t show_rpm_max(struct device *dev,
 271                             struct device_attribute *attr, char *buf)
 272 {
 273         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 274
 275         return sprintf(buf, "%d\n",
 276                        fan_data->speed[fan_data->num_speed - 1].rpm);
 277 }
 278
 279 static ssize_t show_rpm(struct device *dev,
 280                         struct device_attribute *attr, char *buf)
 281 {
 282         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 283
 284         return sprintf(buf, "%d\n", fan_data->speed[fan_data->speed_index].rpm);
 285 }
 286
 287 static ssize_t set_rpm(struct device *dev, struct device_attribute *attr,
 288                        const char *buf, size_t count)
 289 {
 290         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 291         unsigned long rpm;
 292         int ret = count;
 293
 294         if (kstrtoul(buf, 10, &rpm))
 295                 return -EINVAL;
 296
 297         mutex_lock(&fan_data->lock);
 298
 299         if (!fan_data->pwm_enable) {
 300                 ret = -EPERM;
 301                 goto exit_unlock;
 302         }
 303
 304         set_fan_speed(fan_data, rpm_to_speed_index(fan_data, rpm));
 305
 306 exit_unlock:
 307         mutex_unlock(&fan_data->lock);
 308
 309         return ret;
 310 }
 311
 312 static ssize_t show_name(struct device *dev,
 313                          struct device_attribute *attr, char *buf)
 314 {
 315         return sprintf(buf, "gpio-fan\n");
 316 }
 317
 318 static DEVICE_ATTR(pwm1, S_IRUGO | S_IWUSR, show_pwm, set_pwm);
 319 static DEVICE_ATTR(pwm1_enable, S_IRUGO | S_IWUSR,
 320                    show_pwm_enable, set_pwm_enable);
 321 static DEVICE_ATTR(pwm1_mode, S_IRUGO, show_pwm_mode, NULL);
 322 static DEVICE_ATTR(fan1_min, S_IRUGO, show_rpm_min, NULL);
 323 static DEVICE_ATTR(fan1_max, S_IRUGO, show_rpm_max, NULL);
 324 static DEVICE_ATTR(fan1_input, S_IRUGO, show_rpm, NULL);
 325 static DEVICE_ATTR(fan1_target, S_IRUGO | S_IWUSR, show_rpm, set_rpm);
 326
 327 static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
 328
 329 static umode_t gpio_fan_is_visible(struct kobject *kobj,
 330                                    struct attribute *attr, int index)
 331 {
 332         struct device *dev = container_of(kobj, struct device, kobj);
 333         struct gpio_fan_data *data = dev_get_drvdata(dev);
 334
 335         if (index == 1 && !data->alarm)
 336                 return 0;
 337         if (index > 1 && !data->ctrl)
 338                 return 0;
 339
 340         return attr->mode;
 341 }
 342
 343 static struct attribute *gpio_fan_attributes[] = {
 344         &dev_attr_name.attr,
 345         &dev_attr_fan1_alarm.attr,              /* 1 */
 346         &dev_attr_pwm1.attr,                    /* 2 */
 347         &dev_attr_pwm1_enable.attr,
 348         &dev_attr_pwm1_mode.attr,
 349         &dev_attr_fan1_input.attr,
 350         &dev_attr_fan1_target.attr,
 351         &dev_attr_fan1_min.attr,
 352         &dev_attr_fan1_max.attr,
 353         NULL
 354 };
 355
 356 static const struct attribute_group gpio_fan_group = {
 357         .attrs = gpio_fan_attributes,
 358         .is_visible = gpio_fan_is_visible,
 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], gpio_get_value(ctrl[i]));
 376                 if (err)
 377                         return err;
 378         }
 379
 380         fan_data->num_ctrl = num_ctrl;
 381         fan_data->ctrl = ctrl;
 382         fan_data->num_speed = pdata->num_speed;
 383         fan_data->speed = pdata->speed;
 384         fan_data->pwm_enable = true; /* Enable manual fan speed control. */
 385         fan_data->speed_index = get_fan_speed_index(fan_data);
 386         if (fan_data->speed_index < 0)
 387                 return -ENODEV;
 388
 389         return 0;
 390 }
 391
 392 #ifdef CONFIG_OF_GPIO
 393 /*
 394  * Translate OpenFirmware node properties into platform_data
 395  */
 396 static int gpio_fan_get_of_pdata(struct device *dev,
 397                             struct gpio_fan_platform_data *pdata)
 398 {
 399         struct device_node *node;
 400         struct gpio_fan_speed *speed;
 401         unsigned *ctrl;
 402         unsigned i;
 403         u32 u;
 404         struct property *prop;
 405         const __be32 *p;
 406
 407         node = dev->of_node;
 408
 409         /* Fill GPIO pin array */
 410         pdata->num_ctrl = of_gpio_count(node);
 411         if (pdata->num_ctrl <= 0) {
 412                 dev_err(dev, "gpios DT property empty / missing");
 413                 return -ENODEV;
 414         }
 415         ctrl = devm_kzalloc(dev, pdata->num_ctrl * sizeof(unsigned),
 416                                 GFP_KERNEL);
 417         if (!ctrl)
 418                 return -ENOMEM;
 419         for (i = 0; i < pdata->num_ctrl; i++) {
 420                 int val;
 421
 422                 val = of_get_gpio(node, i);
 423                 if (val < 0)
 424                         return val;
 425                 ctrl[i] = val;
 426         }
 427         pdata->ctrl = ctrl;
 428
 429         /* Get number of RPM/ctrl_val pairs in speed map */
 430         prop = of_find_property(node, "gpio-fan,speed-map", &i);
 431         if (!prop) {
 432                 dev_err(dev, "gpio-fan,speed-map DT property missing");
 433                 return -ENODEV;
 434         }
 435         i = i / sizeof(u32);
 436         if (i == 0 || i & 1) {
 437                 dev_err(dev, "gpio-fan,speed-map contains zero/odd number of entries");
 438                 return -ENODEV;
 439         }
 440         pdata->num_speed = i / 2;
 441
 442         /*
 443          * Populate speed map
 444          * Speed map is in the form <RPM ctrl_val RPM ctrl_val ...>
 445          * this needs splitting into pairs to create gpio_fan_speed structs
 446          */
 447         speed = devm_kzalloc(dev,
 448                         pdata->num_speed * sizeof(struct gpio_fan_speed),
 449                         GFP_KERNEL);
 450         if (!speed)
 451                 return -ENOMEM;
 452         p = NULL;
 453         for (i = 0; i < pdata->num_speed; i++) {
 454                 p = of_prop_next_u32(prop, p, &u);
 455                 if (!p)
 456                         return -ENODEV;
 457                 speed[i].rpm = u;
 458                 p = of_prop_next_u32(prop, p, &u);
 459                 if (!p)
 460                         return -ENODEV;
 461                 speed[i].ctrl_val = u;
 462         }
 463         pdata->speed = speed;
 464
 465         /* Alarm GPIO if one exists */
 466         if (of_gpio_named_count(node, "alarm-gpios") > 0) {
 467                 struct gpio_fan_alarm *alarm;
 468                 int val;
 469                 enum of_gpio_flags flags;
 470
 471                 alarm = devm_kzalloc(dev, sizeof(struct gpio_fan_alarm),
 472                                         GFP_KERNEL);
 473                 if (!alarm)
 474                         return -ENOMEM;
 475
 476                 val = of_get_named_gpio_flags(node, "alarm-gpios", 0, &flags);
 477                 if (val < 0)
 478                         return val;
 479                 alarm->gpio = val;
 480                 alarm->active_low = flags & OF_GPIO_ACTIVE_LOW;
 481
 482                 pdata->alarm = alarm;
 483         }
 484
 485         return 0;
 486 }
 487
 488 static struct of_device_id of_gpio_fan_match[] = {
 489         { .compatible = "gpio-fan", },
 490         {},
 491 };
 492 #endif /* CONFIG_OF_GPIO */
 493
 494 static int gpio_fan_probe(struct platform_device *pdev)
 495 {
 496         int err;
 497         struct gpio_fan_data *fan_data;
 498         struct gpio_fan_platform_data *pdata = pdev->dev.platform_data;
 499
 500 #ifdef CONFIG_OF_GPIO
 501         if (!pdata) {
 502                 pdata = devm_kzalloc(&pdev->dev,
 503                                         sizeof(struct gpio_fan_platform_data),
 504                                         GFP_KERNEL);
 505                 if (!pdata)
 506                         return -ENOMEM;
 507
 508                 err = gpio_fan_get_of_pdata(&pdev->dev, pdata);
 509                 if (err)
 510                         return err;
 511         }
 512 #else /* CONFIG_OF_GPIO */
 513         if (!pdata)
 514                 return -EINVAL;
 515 #endif /* CONFIG_OF_GPIO */
 516
 517         fan_data = devm_kzalloc(&pdev->dev, sizeof(struct gpio_fan_data),
 518                                 GFP_KERNEL);
 519         if (!fan_data)
 520                 return -ENOMEM;
 521
 522         fan_data->pdev = pdev;
 523         platform_set_drvdata(pdev, fan_data);
 524         mutex_init(&fan_data->lock);
 525
 526         /* Configure alarm GPIO if available. */
 527         if (pdata->alarm) {
 528                 err = fan_alarm_init(fan_data, pdata->alarm);
 529                 if (err)
 530                         return err;
 531         }
 532
 533         /* Configure control GPIOs if available. */
 534         if (pdata->ctrl && pdata->num_ctrl > 0) {
 535                 if (!pdata->speed || pdata->num_speed <= 1)
 536                         return -EINVAL;
 537                 err = fan_ctrl_init(fan_data, pdata);
 538                 if (err)
 539                         return err;
 540         }
 541
 542         err = sysfs_create_group(&pdev->dev.kobj, &gpio_fan_group);
 543         if (err)
 544                 return err;
 545
 546         /* Make this driver part of hwmon class. */
 547         fan_data->hwmon_dev = hwmon_device_register(&pdev->dev);
 548         if (IS_ERR(fan_data->hwmon_dev)) {
 549                 err = PTR_ERR(fan_data->hwmon_dev);
 550                 goto err_remove;
 551         }
 552
 553         dev_info(&pdev->dev, "GPIO fan initialized\n");
 554
 555         return 0;
 556
 557 err_remove:
 558         sysfs_remove_group(&pdev->dev.kobj, &gpio_fan_group);
 559         return err;
 560 }
 561
 562 static int gpio_fan_remove(struct platform_device *pdev)
 563 {
 564         struct gpio_fan_data *fan_data = platform_get_drvdata(pdev);
 565
 566         hwmon_device_unregister(fan_data->hwmon_dev);
 567         sysfs_remove_group(&pdev->dev.kobj, &gpio_fan_group);
 568
 569         return 0;
 570 }
 571
 572 #ifdef CONFIG_PM_SLEEP
 573 static int gpio_fan_suspend(struct device *dev)
 574 {
 575         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 576
 577         if (fan_data->ctrl) {
 578                 fan_data->resume_speed = fan_data->speed_index;
 579                 set_fan_speed(fan_data, 0);
 580         }
 581
 582         return 0;
 583 }
 584
 585 static int gpio_fan_resume(struct device *dev)
 586 {
 587         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 588
 589         if (fan_data->ctrl)
 590                 set_fan_speed(fan_data, fan_data->resume_speed);
 591
 592         return 0;
 593 }
 594
 595 static SIMPLE_DEV_PM_OPS(gpio_fan_pm, gpio_fan_suspend, gpio_fan_resume);
 596 #define GPIO_FAN_PM     (&gpio_fan_pm)
 597 #else
 598 #define GPIO_FAN_PM     NULL
 599 #endif
 600
 601 static struct platform_driver gpio_fan_driver = {
 602         .probe          = gpio_fan_probe,
 603         .remove         = gpio_fan_remove,
 604         .driver = {
 605                 .name   = "gpio-fan",
 606                 .pm     = GPIO_FAN_PM,
 607 #ifdef CONFIG_OF_GPIO
 608                 .of_match_table = of_match_ptr(of_gpio_fan_match),
 609 #endif
 610         },
 611 };
 612
 613 module_platform_driver(gpio_fan_driver);
 614
 615 MODULE_AUTHOR("Simon Guinot <sguinot@lacie.com>");
 616 MODULE_DESCRIPTION("GPIO FAN driver");
 617 MODULE_LICENSE("GPL");
 618 MODULE_ALIAS("platform:gpio-fan");