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
  35 struct gpio_fan_data {
  36         struct platform_device  *pdev;
  37         struct device           *hwmon_dev;
  38         struct mutex            lock; /* lock GPIOs operations. */
  39         int                     num_ctrl;
  40         unsigned                *ctrl;
  41         int                     num_speed;
  42         struct gpio_fan_speed   *speed;
  43         int                     speed_index;
  44 #ifdef CONFIG_PM
  45         int                     resume_speed;
  46 #endif
  47         bool                    pwm_enable;
  48         struct gpio_fan_alarm   *alarm;
  49         struct work_struct      alarm_work;
  50 };
  51
  52 /*
  53  * Alarm GPIO.
  54  */
  55
  56 static void fan_alarm_notify(struct work_struct *ws)
  57 {
  58         struct gpio_fan_data *fan_data =
  59                 container_of(ws, struct gpio_fan_data, alarm_work);
  60
  61         sysfs_notify(&fan_data->pdev->dev.kobj, NULL, "fan1_alarm");
  62         kobject_uevent(&fan_data->pdev->dev.kobj, KOBJ_CHANGE);
  63 }
  64
  65 static irqreturn_t fan_alarm_irq_handler(int irq, void *dev_id)
  66 {
  67         struct gpio_fan_data *fan_data = dev_id;
  68
  69         schedule_work(&fan_data->alarm_work);
  70
  71         return IRQ_NONE;
  72 }
  73
  74 static ssize_t show_fan_alarm(struct device *dev,
  75                               struct device_attribute *attr, char *buf)
  76 {
  77         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
  78         struct gpio_fan_alarm *alarm = fan_data->alarm;
  79         int value = gpio_get_value(alarm->gpio);
  80
  81         if (alarm->active_low)
  82                 value = !value;
  83
  84         return sprintf(buf, "%d\n", value);
  85 }
  86
  87 static DEVICE_ATTR(fan1_alarm, S_IRUGO, show_fan_alarm, NULL);
  88
  89 static int fan_alarm_init(struct gpio_fan_data *fan_data,
  90                           struct gpio_fan_alarm *alarm)
  91 {
  92         int err;
  93         int alarm_irq;
  94         struct platform_device *pdev = fan_data->pdev;
  95
  96         fan_data->alarm = alarm;
  97
  98         err = gpio_request(alarm->gpio, "GPIO fan alarm");
  99         if (err)
 100                 return err;
 101
 102         err = gpio_direction_input(alarm->gpio);
 103         if (err)
 104                 goto err_free_gpio;
 105
 106         err = device_create_file(&pdev->dev, &dev_attr_fan1_alarm);
 107         if (err)
 108                 goto err_free_gpio;
 109
 110         /*
 111          * If the alarm GPIO don't support interrupts, just leave
 112          * without initializing the fail notification support.
 113          */
 114         alarm_irq = gpio_to_irq(alarm->gpio);
 115         if (alarm_irq < 0)
 116                 return 0;
 117
 118         INIT_WORK(&fan_data->alarm_work, fan_alarm_notify);
 119         irq_set_irq_type(alarm_irq, IRQ_TYPE_EDGE_BOTH);
 120         err = request_irq(alarm_irq, fan_alarm_irq_handler, IRQF_SHARED,
 121                           "GPIO fan alarm", fan_data);
 122         if (err)
 123                 goto err_free_sysfs;
 124
 125         return 0;
 126
 127 err_free_sysfs:
 128         device_remove_file(&pdev->dev, &dev_attr_fan1_alarm);
 129 err_free_gpio:
 130         gpio_free(alarm->gpio);
 131
 132         return err;
 133 }
 134
 135 static void fan_alarm_free(struct gpio_fan_data *fan_data)
 136 {
 137         struct platform_device *pdev = fan_data->pdev;
 138         int alarm_irq = gpio_to_irq(fan_data->alarm->gpio);
 139
 140         if (alarm_irq >= 0)
 141                 free_irq(alarm_irq, fan_data);
 142         device_remove_file(&pdev->dev, &dev_attr_fan1_alarm);
 143         gpio_free(fan_data->alarm->gpio);
 144 }
 145
 146 /*
 147  * Control GPIOs.
 148  */
 149
 150 /* Must be called with fan_data->lock held, except during initialization. */
 151 static void __set_fan_ctrl(struct gpio_fan_data *fan_data, int ctrl_val)
 152 {
 153         int i;
 154
 155         for (i = 0; i < fan_data->num_ctrl; i++)
 156                 gpio_set_value(fan_data->ctrl[i], (ctrl_val >> i) & 1);
 157 }
 158
 159 static int __get_fan_ctrl(struct gpio_fan_data *fan_data)
 160 {
 161         int i;
 162         int ctrl_val = 0;
 163
 164         for (i = 0; i < fan_data->num_ctrl; i++) {
 165                 int value;
 166
 167                 value = gpio_get_value(fan_data->ctrl[i]);
 168                 ctrl_val |= (value << i);
 169         }
 170         return ctrl_val;
 171 }
 172
 173 /* Must be called with fan_data->lock held, except during initialization. */
 174 static void set_fan_speed(struct gpio_fan_data *fan_data, int speed_index)
 175 {
 176         if (fan_data->speed_index == speed_index)
 177                 return;
 178
 179         __set_fan_ctrl(fan_data, fan_data->speed[speed_index].ctrl_val);
 180         fan_data->speed_index = speed_index;
 181 }
 182
 183 static int get_fan_speed_index(struct gpio_fan_data *fan_data)
 184 {
 185         int ctrl_val = __get_fan_ctrl(fan_data);
 186         int i;
 187
 188         for (i = 0; i < fan_data->num_speed; i++)
 189                 if (fan_data->speed[i].ctrl_val == ctrl_val)
 190                         return i;
 191
 192         dev_warn(&fan_data->pdev->dev,
 193                  "missing speed array entry for GPIO value 0x%x\n", ctrl_val);
 194
 195         return -EINVAL;
 196 }
 197
 198 static int rpm_to_speed_index(struct gpio_fan_data *fan_data, int rpm)
 199 {
 200         struct gpio_fan_speed *speed = fan_data->speed;
 201         int i;
 202
 203         for (i = 0; i < fan_data->num_speed; i++)
 204                 if (speed[i].rpm >= rpm)
 205                         return i;
 206
 207         return fan_data->num_speed - 1;
 208 }
 209
 210 static ssize_t show_pwm(struct device *dev,
 211                         struct device_attribute *attr, char *buf)
 212 {
 213         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 214         u8 pwm = fan_data->speed_index * 255 / (fan_data->num_speed - 1);
 215
 216         return sprintf(buf, "%d\n", pwm);
 217 }
 218
 219 static ssize_t set_pwm(struct device *dev, struct device_attribute *attr,
 220                        const char *buf, size_t count)
 221 {
 222         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 223         unsigned long pwm;
 224         int speed_index;
 225         int ret = count;
 226
 227         if (strict_strtoul(buf, 10, &pwm) || pwm > 255)
 228                 return -EINVAL;
 229
 230         mutex_lock(&fan_data->lock);
 231
 232         if (!fan_data->pwm_enable) {
 233                 ret = -EPERM;
 234                 goto exit_unlock;
 235         }
 236
 237         speed_index = DIV_ROUND_UP(pwm * (fan_data->num_speed - 1), 255);
 238         set_fan_speed(fan_data, speed_index);
 239
 240 exit_unlock:
 241         mutex_unlock(&fan_data->lock);
 242
 243         return ret;
 244 }
 245
 246 static ssize_t show_pwm_enable(struct device *dev,
 247                                struct device_attribute *attr, char *buf)
 248 {
 249         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 250
 251         return sprintf(buf, "%d\n", fan_data->pwm_enable);
 252 }
 253
 254 static ssize_t set_pwm_enable(struct device *dev, struct device_attribute *attr,
 255                               const char *buf, size_t count)
 256 {
 257         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 258         unsigned long val;
 259
 260         if (strict_strtoul(buf, 10, &val) || val > 1)
 261                 return -EINVAL;
 262
 263         if (fan_data->pwm_enable == val)
 264                 return count;
 265
 266         mutex_lock(&fan_data->lock);
 267
 268         fan_data->pwm_enable = val;
 269
 270         /* Disable manual control mode: set fan at full speed. */
 271         if (val == 0)
 272                 set_fan_speed(fan_data, fan_data->num_speed - 1);
 273
 274         mutex_unlock(&fan_data->lock);
 275
 276         return count;
 277 }
 278
 279 static ssize_t show_pwm_mode(struct device *dev,
 280                              struct device_attribute *attr, char *buf)
 281 {
 282         return sprintf(buf, "0\n");
 283 }
 284
 285 static ssize_t show_rpm_min(struct device *dev,
 286                             struct device_attribute *attr, char *buf)
 287 {
 288         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 289
 290         return sprintf(buf, "%d\n", fan_data->speed[0].rpm);
 291 }
 292
 293 static ssize_t show_rpm_max(struct device *dev,
 294                             struct device_attribute *attr, char *buf)
 295 {
 296         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 297
 298         return sprintf(buf, "%d\n",
 299                        fan_data->speed[fan_data->num_speed - 1].rpm);
 300 }
 301
 302 static ssize_t show_rpm(struct device *dev,
 303                         struct device_attribute *attr, char *buf)
 304 {
 305         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 306
 307         return sprintf(buf, "%d\n", fan_data->speed[fan_data->speed_index].rpm);
 308 }
 309
 310 static ssize_t set_rpm(struct device *dev, struct device_attribute *attr,
 311                        const char *buf, size_t count)
 312 {
 313         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 314         unsigned long rpm;
 315         int ret = count;
 316
 317         if (strict_strtoul(buf, 10, &rpm))
 318                 return -EINVAL;
 319
 320         mutex_lock(&fan_data->lock);
 321
 322         if (!fan_data->pwm_enable) {
 323                 ret = -EPERM;
 324                 goto exit_unlock;
 325         }
 326
 327         set_fan_speed(fan_data, rpm_to_speed_index(fan_data, rpm));
 328
 329 exit_unlock:
 330         mutex_unlock(&fan_data->lock);
 331
 332         return ret;
 333 }
 334
 335 static DEVICE_ATTR(pwm1, S_IRUGO | S_IWUSR, show_pwm, set_pwm);
 336 static DEVICE_ATTR(pwm1_enable, S_IRUGO | S_IWUSR,
 337                    show_pwm_enable, set_pwm_enable);
 338 static DEVICE_ATTR(pwm1_mode, S_IRUGO, show_pwm_mode, NULL);
 339 static DEVICE_ATTR(fan1_min, S_IRUGO, show_rpm_min, NULL);
 340 static DEVICE_ATTR(fan1_max, S_IRUGO, show_rpm_max, NULL);
 341 static DEVICE_ATTR(fan1_input, S_IRUGO, show_rpm, NULL);
 342 static DEVICE_ATTR(fan1_target, S_IRUGO | S_IWUSR, show_rpm, set_rpm);
 343
 344 static struct attribute *gpio_fan_ctrl_attributes[] = {
 345         &dev_attr_pwm1.attr,
 346         &dev_attr_pwm1_enable.attr,
 347         &dev_attr_pwm1_mode.attr,
 348         &dev_attr_fan1_input.attr,
 349         &dev_attr_fan1_target.attr,
 350         &dev_attr_fan1_min.attr,
 351         &dev_attr_fan1_max.attr,
 352         NULL
 353 };
 354
 355 static const struct attribute_group gpio_fan_ctrl_group = {
 356         .attrs = gpio_fan_ctrl_attributes,
 357 };
 358
 359 static int fan_ctrl_init(struct gpio_fan_data *fan_data,
 360                          struct gpio_fan_platform_data *pdata)
 361 {
 362         struct platform_device *pdev = fan_data->pdev;
 363         int num_ctrl = pdata->num_ctrl;
 364         unsigned *ctrl = pdata->ctrl;
 365         int i, err;
 366
 367         for (i = 0; i < num_ctrl; i++) {
 368                 err = gpio_request(ctrl[i], "GPIO fan control");
 369                 if (err)
 370                         goto err_free_gpio;
 371
 372                 err = gpio_direction_output(ctrl[i], gpio_get_value(ctrl[i]));
 373                 if (err) {
 374                         gpio_free(ctrl[i]);
 375                         goto err_free_gpio;
 376                 }
 377         }
 378
 379         fan_data->num_ctrl = num_ctrl;
 380         fan_data->ctrl = ctrl;
 381         fan_data->num_speed = pdata->num_speed;
 382         fan_data->speed = pdata->speed;
 383         fan_data->pwm_enable = true; /* Enable manual fan speed control. */
 384         fan_data->speed_index = get_fan_speed_index(fan_data);
 385         if (fan_data->speed_index < 0) {
 386                 err = -ENODEV;
 387                 goto err_free_gpio;
 388         }
 389
 390         err = sysfs_create_group(&pdev->dev.kobj, &gpio_fan_ctrl_group);
 391         if (err)
 392                 goto err_free_gpio;
 393
 394         return 0;
 395
 396 err_free_gpio:
 397         for (i = i - 1; i >= 0; i--)
 398                 gpio_free(ctrl[i]);
 399
 400         return err;
 401 }
 402
 403 static void fan_ctrl_free(struct gpio_fan_data *fan_data)
 404 {
 405         struct platform_device *pdev = fan_data->pdev;
 406         int i;
 407
 408         sysfs_remove_group(&pdev->dev.kobj, &gpio_fan_ctrl_group);
 409         for (i = 0; i < fan_data->num_ctrl; i++)
 410                 gpio_free(fan_data->ctrl[i]);
 411 }
 412
 413 /*
 414  * Platform driver.
 415  */
 416
 417 static ssize_t show_name(struct device *dev,
 418                          struct device_attribute *attr, char *buf)
 419 {
 420         return sprintf(buf, "gpio-fan\n");
 421 }
 422
 423 static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
 424
 425 static int __devinit gpio_fan_probe(struct platform_device *pdev)
 426 {
 427         int err;
 428         struct gpio_fan_data *fan_data;
 429         struct gpio_fan_platform_data *pdata = pdev->dev.platform_data;
 430
 431         if (!pdata)
 432                 return -EINVAL;
 433
 434         fan_data = kzalloc(sizeof(struct gpio_fan_data), GFP_KERNEL);
 435         if (!fan_data)
 436                 return -ENOMEM;
 437
 438         fan_data->pdev = pdev;
 439         platform_set_drvdata(pdev, fan_data);
 440         mutex_init(&fan_data->lock);
 441
 442         /* Configure alarm GPIO if available. */
 443         if (pdata->alarm) {
 444                 err = fan_alarm_init(fan_data, pdata->alarm);
 445                 if (err)
 446                         goto err_free_data;
 447         }
 448
 449         /* Configure control GPIOs if available. */
 450         if (pdata->ctrl && pdata->num_ctrl > 0) {
 451                 if (!pdata->speed || pdata->num_speed <= 1) {
 452                         err = -EINVAL;
 453                         goto err_free_alarm;
 454                 }
 455                 err = fan_ctrl_init(fan_data, pdata);
 456                 if (err)
 457                         goto err_free_alarm;
 458         }
 459
 460         err = device_create_file(&pdev->dev, &dev_attr_name);
 461         if (err)
 462                 goto err_free_ctrl;
 463
 464         /* Make this driver part of hwmon class. */
 465         fan_data->hwmon_dev = hwmon_device_register(&pdev->dev);
 466         if (IS_ERR(fan_data->hwmon_dev)) {
 467                 err = PTR_ERR(fan_data->hwmon_dev);
 468                 goto err_remove_name;
 469         }
 470
 471         dev_info(&pdev->dev, "GPIO fan initialized\n");
 472
 473         return 0;
 474
 475 err_remove_name:
 476         device_remove_file(&pdev->dev, &dev_attr_name);
 477 err_free_ctrl:
 478         if (fan_data->ctrl)
 479                 fan_ctrl_free(fan_data);
 480 err_free_alarm:
 481         if (fan_data->alarm)
 482                 fan_alarm_free(fan_data);
 483 err_free_data:
 484         platform_set_drvdata(pdev, NULL);
 485         kfree(fan_data);
 486
 487         return err;
 488 }
 489
 490 static int __devexit gpio_fan_remove(struct platform_device *pdev)
 491 {
 492         struct gpio_fan_data *fan_data = platform_get_drvdata(pdev);
 493
 494         hwmon_device_unregister(fan_data->hwmon_dev);
 495         device_remove_file(&pdev->dev, &dev_attr_name);
 496         if (fan_data->alarm)
 497                 fan_alarm_free(fan_data);
 498         if (fan_data->ctrl)
 499                 fan_ctrl_free(fan_data);
 500         kfree(fan_data);
 501
 502         return 0;
 503 }
 504
 505 #ifdef CONFIG_PM
 506 static int gpio_fan_suspend(struct platform_device *pdev, pm_message_t state)
 507 {
 508         struct gpio_fan_data *fan_data = platform_get_drvdata(pdev);
 509
 510         if (fan_data->ctrl) {
 511                 fan_data->resume_speed = fan_data->speed_index;
 512                 set_fan_speed(fan_data, 0);
 513         }
 514
 515         return 0;
 516 }
 517
 518 static int gpio_fan_resume(struct platform_device *pdev)
 519 {
 520         struct gpio_fan_data *fan_data = platform_get_drvdata(pdev);
 521
 522         if (fan_data->ctrl)
 523                 set_fan_speed(fan_data, fan_data->resume_speed);
 524
 525         return 0;
 526 }
 527 #else
 528 #define gpio_fan_suspend NULL
 529 #define gpio_fan_resume NULL
 530 #endif
 531
 532 static struct platform_driver gpio_fan_driver = {
 533         .probe          = gpio_fan_probe,
 534         .remove         = __devexit_p(gpio_fan_remove),
 535         .suspend        = gpio_fan_suspend,
 536         .resume         = gpio_fan_resume,
 537         .driver = {
 538                 .name   = "gpio-fan",
 539         },
 540 };
 541
 542 static int __init gpio_fan_init(void)
 543 {
 544         return platform_driver_register(&gpio_fan_driver);
 545 }
 546
 547 static void __exit gpio_fan_exit(void)
 548 {
 549         platform_driver_unregister(&gpio_fan_driver);
 550 }
 551
 552 module_init(gpio_fan_init);
 553 module_exit(gpio_fan_exit);
 554
 555 MODULE_AUTHOR("Simon Guinot <sguinot@lacie.com>");
 556 MODULE_DESCRIPTION("GPIO FAN driver");
 557 MODULE_LICENSE("GPL");
 558 MODULE_ALIAS("platform:gpio-fan");