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_SLEEP
  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 = devm_gpio_request(&pdev->dev, alarm->gpio, "GPIO fan alarm");
  99         if (err)
 100                 return err;
 101
 102         err = gpio_direction_input(alarm->gpio);
 103         if (err)
 104                 return err;
 105
 106         err = device_create_file(&pdev->dev, &dev_attr_fan1_alarm);
 107         if (err)
 108                 return err;
 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 = devm_request_irq(&pdev->dev, alarm_irq, fan_alarm_irq_handler,
 121                                IRQF_SHARED, "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         return err;
 130 }
 131
 132 static void fan_alarm_free(struct gpio_fan_data *fan_data)
 133 {
 134         struct platform_device *pdev = fan_data->pdev;
 135
 136         device_remove_file(&pdev->dev, &dev_attr_fan1_alarm);
 137 }
 138
 139 /*
 140  * Control GPIOs.
 141  */
 142
 143 /* Must be called with fan_data->lock held, except during initialization. */
 144 static void __set_fan_ctrl(struct gpio_fan_data *fan_data, int ctrl_val)
 145 {
 146         int i;
 147
 148         for (i = 0; i < fan_data->num_ctrl; i++)
 149                 gpio_set_value(fan_data->ctrl[i], (ctrl_val >> i) & 1);
 150 }
 151
 152 static int __get_fan_ctrl(struct gpio_fan_data *fan_data)
 153 {
 154         int i;
 155         int ctrl_val = 0;
 156
 157         for (i = 0; i < fan_data->num_ctrl; i++) {
 158                 int value;
 159
 160                 value = gpio_get_value(fan_data->ctrl[i]);
 161                 ctrl_val |= (value << i);
 162         }
 163         return ctrl_val;
 164 }
 165
 166 /* Must be called with fan_data->lock held, except during initialization. */
 167 static void set_fan_speed(struct gpio_fan_data *fan_data, int speed_index)
 168 {
 169         if (fan_data->speed_index == speed_index)
 170                 return;
 171
 172         __set_fan_ctrl(fan_data, fan_data->speed[speed_index].ctrl_val);
 173         fan_data->speed_index = speed_index;
 174 }
 175
 176 static int get_fan_speed_index(struct gpio_fan_data *fan_data)
 177 {
 178         int ctrl_val = __get_fan_ctrl(fan_data);
 179         int i;
 180
 181         for (i = 0; i < fan_data->num_speed; i++)
 182                 if (fan_data->speed[i].ctrl_val == ctrl_val)
 183                         return i;
 184
 185         dev_warn(&fan_data->pdev->dev,
 186                  "missing speed array entry for GPIO value 0x%x\n", ctrl_val);
 187
 188         return -EINVAL;
 189 }
 190
 191 static int rpm_to_speed_index(struct gpio_fan_data *fan_data, int rpm)
 192 {
 193         struct gpio_fan_speed *speed = fan_data->speed;
 194         int i;
 195
 196         for (i = 0; i < fan_data->num_speed; i++)
 197                 if (speed[i].rpm >= rpm)
 198                         return i;
 199
 200         return fan_data->num_speed - 1;
 201 }
 202
 203 static ssize_t show_pwm(struct device *dev,
 204                         struct device_attribute *attr, char *buf)
 205 {
 206         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 207         u8 pwm = fan_data->speed_index * 255 / (fan_data->num_speed - 1);
 208
 209         return sprintf(buf, "%d\n", pwm);
 210 }
 211
 212 static ssize_t set_pwm(struct device *dev, struct device_attribute *attr,
 213                        const char *buf, size_t count)
 214 {
 215         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 216         unsigned long pwm;
 217         int speed_index;
 218         int ret = count;
 219
 220         if (kstrtoul(buf, 10, &pwm) || pwm > 255)
 221                 return -EINVAL;
 222
 223         mutex_lock(&fan_data->lock);
 224
 225         if (!fan_data->pwm_enable) {
 226                 ret = -EPERM;
 227                 goto exit_unlock;
 228         }
 229
 230         speed_index = DIV_ROUND_UP(pwm * (fan_data->num_speed - 1), 255);
 231         set_fan_speed(fan_data, speed_index);
 232
 233 exit_unlock:
 234         mutex_unlock(&fan_data->lock);
 235
 236         return ret;
 237 }
 238
 239 static ssize_t show_pwm_enable(struct device *dev,
 240                                struct device_attribute *attr, char *buf)
 241 {
 242         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 243
 244         return sprintf(buf, "%d\n", fan_data->pwm_enable);
 245 }
 246
 247 static ssize_t set_pwm_enable(struct device *dev, struct device_attribute *attr,
 248                               const char *buf, size_t count)
 249 {
 250         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 251         unsigned long val;
 252
 253         if (kstrtoul(buf, 10, &val) || val > 1)
 254                 return -EINVAL;
 255
 256         if (fan_data->pwm_enable == val)
 257                 return count;
 258
 259         mutex_lock(&fan_data->lock);
 260
 261         fan_data->pwm_enable = val;
 262
 263         /* Disable manual control mode: set fan at full speed. */
 264         if (val == 0)
 265                 set_fan_speed(fan_data, fan_data->num_speed - 1);
 266
 267         mutex_unlock(&fan_data->lock);
 268
 269         return count;
 270 }
 271
 272 static ssize_t show_pwm_mode(struct device *dev,
 273                              struct device_attribute *attr, char *buf)
 274 {
 275         return sprintf(buf, "0\n");
 276 }
 277
 278 static ssize_t show_rpm_min(struct device *dev,
 279                             struct device_attribute *attr, char *buf)
 280 {
 281         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 282
 283         return sprintf(buf, "%d\n", fan_data->speed[0].rpm);
 284 }
 285
 286 static ssize_t show_rpm_max(struct device *dev,
 287                             struct device_attribute *attr, char *buf)
 288 {
 289         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 290
 291         return sprintf(buf, "%d\n",
 292                        fan_data->speed[fan_data->num_speed - 1].rpm);
 293 }
 294
 295 static ssize_t show_rpm(struct device *dev,
 296                         struct device_attribute *attr, char *buf)
 297 {
 298         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 299
 300         return sprintf(buf, "%d\n", fan_data->speed[fan_data->speed_index].rpm);
 301 }
 302
 303 static ssize_t set_rpm(struct device *dev, struct device_attribute *attr,
 304                        const char *buf, size_t count)
 305 {
 306         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 307         unsigned long rpm;
 308         int ret = count;
 309
 310         if (kstrtoul(buf, 10, &rpm))
 311                 return -EINVAL;
 312
 313         mutex_lock(&fan_data->lock);
 314
 315         if (!fan_data->pwm_enable) {
 316                 ret = -EPERM;
 317                 goto exit_unlock;
 318         }
 319
 320         set_fan_speed(fan_data, rpm_to_speed_index(fan_data, rpm));
 321
 322 exit_unlock:
 323         mutex_unlock(&fan_data->lock);
 324
 325         return ret;
 326 }
 327
 328 static DEVICE_ATTR(pwm1, S_IRUGO | S_IWUSR, show_pwm, set_pwm);
 329 static DEVICE_ATTR(pwm1_enable, S_IRUGO | S_IWUSR,
 330                    show_pwm_enable, set_pwm_enable);
 331 static DEVICE_ATTR(pwm1_mode, S_IRUGO, show_pwm_mode, NULL);
 332 static DEVICE_ATTR(fan1_min, S_IRUGO, show_rpm_min, NULL);
 333 static DEVICE_ATTR(fan1_max, S_IRUGO, show_rpm_max, NULL);
 334 static DEVICE_ATTR(fan1_input, S_IRUGO, show_rpm, NULL);
 335 static DEVICE_ATTR(fan1_target, S_IRUGO | S_IWUSR, show_rpm, set_rpm);
 336
 337 static struct attribute *gpio_fan_ctrl_attributes[] = {
 338         &dev_attr_pwm1.attr,
 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_ctrl_group = {
 349         .attrs = gpio_fan_ctrl_attributes,
 350 };
 351
 352 static int fan_ctrl_init(struct gpio_fan_data *fan_data,
 353                          struct gpio_fan_platform_data *pdata)
 354 {
 355         struct platform_device *pdev = fan_data->pdev;
 356         int num_ctrl = pdata->num_ctrl;
 357         unsigned *ctrl = pdata->ctrl;
 358         int i, err;
 359
 360         for (i = 0; i < num_ctrl; i++) {
 361                 err = devm_gpio_request(&pdev->dev, ctrl[i],
 362                                         "GPIO fan control");
 363                 if (err)
 364                         return err;
 365
 366                 err = gpio_direction_output(ctrl[i], gpio_get_value(ctrl[i]));
 367                 if (err)
 368                         return err;
 369         }
 370
 371         fan_data->num_ctrl = num_ctrl;
 372         fan_data->ctrl = ctrl;
 373         fan_data->num_speed = pdata->num_speed;
 374         fan_data->speed = pdata->speed;
 375         fan_data->pwm_enable = true; /* Enable manual fan speed control. */
 376         fan_data->speed_index = get_fan_speed_index(fan_data);
 377         if (fan_data->speed_index < 0)
 378                 return -ENODEV;
 379
 380         err = sysfs_create_group(&pdev->dev.kobj, &gpio_fan_ctrl_group);
 381         return err;
 382 }
 383
 384 static void fan_ctrl_free(struct gpio_fan_data *fan_data)
 385 {
 386         struct platform_device *pdev = fan_data->pdev;
 387
 388         sysfs_remove_group(&pdev->dev.kobj, &gpio_fan_ctrl_group);
 389 }
 390
 391 /*
 392  * Platform driver.
 393  */
 394
 395 static ssize_t show_name(struct device *dev,
 396                          struct device_attribute *attr, char *buf)
 397 {
 398         return sprintf(buf, "gpio-fan\n");
 399 }
 400
 401 static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
 402
 403 static int __devinit gpio_fan_probe(struct platform_device *pdev)
 404 {
 405         int err;
 406         struct gpio_fan_data *fan_data;
 407         struct gpio_fan_platform_data *pdata = pdev->dev.platform_data;
 408
 409         if (!pdata)
 410                 return -EINVAL;
 411
 412         fan_data = devm_kzalloc(&pdev->dev, sizeof(struct gpio_fan_data),
 413                                 GFP_KERNEL);
 414         if (!fan_data)
 415                 return -ENOMEM;
 416
 417         fan_data->pdev = pdev;
 418         platform_set_drvdata(pdev, fan_data);
 419         mutex_init(&fan_data->lock);
 420
 421         /* Configure alarm GPIO if available. */
 422         if (pdata->alarm) {
 423                 err = fan_alarm_init(fan_data, pdata->alarm);
 424                 if (err)
 425                         return err;
 426         }
 427
 428         /* Configure control GPIOs if available. */
 429         if (pdata->ctrl && pdata->num_ctrl > 0) {
 430                 if (!pdata->speed || pdata->num_speed <= 1) {
 431                         err = -EINVAL;
 432                         goto err_free_alarm;
 433                 }
 434                 err = fan_ctrl_init(fan_data, pdata);
 435                 if (err)
 436                         goto err_free_alarm;
 437         }
 438
 439         err = device_create_file(&pdev->dev, &dev_attr_name);
 440         if (err)
 441                 goto err_free_ctrl;
 442
 443         /* Make this driver part of hwmon class. */
 444         fan_data->hwmon_dev = hwmon_device_register(&pdev->dev);
 445         if (IS_ERR(fan_data->hwmon_dev)) {
 446                 err = PTR_ERR(fan_data->hwmon_dev);
 447                 goto err_remove_name;
 448         }
 449
 450         dev_info(&pdev->dev, "GPIO fan initialized\n");
 451
 452         return 0;
 453
 454 err_remove_name:
 455         device_remove_file(&pdev->dev, &dev_attr_name);
 456 err_free_ctrl:
 457         if (fan_data->ctrl)
 458                 fan_ctrl_free(fan_data);
 459 err_free_alarm:
 460         if (fan_data->alarm)
 461                 fan_alarm_free(fan_data);
 462         return err;
 463 }
 464
 465 static int __devexit gpio_fan_remove(struct platform_device *pdev)
 466 {
 467         struct gpio_fan_data *fan_data = platform_get_drvdata(pdev);
 468
 469         hwmon_device_unregister(fan_data->hwmon_dev);
 470         device_remove_file(&pdev->dev, &dev_attr_name);
 471         if (fan_data->alarm)
 472                 fan_alarm_free(fan_data);
 473         if (fan_data->ctrl)
 474                 fan_ctrl_free(fan_data);
 475
 476         return 0;
 477 }
 478
 479 #ifdef CONFIG_PM_SLEEP
 480 static int gpio_fan_suspend(struct device *dev)
 481 {
 482         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 483
 484         if (fan_data->ctrl) {
 485                 fan_data->resume_speed = fan_data->speed_index;
 486                 set_fan_speed(fan_data, 0);
 487         }
 488
 489         return 0;
 490 }
 491
 492 static int gpio_fan_resume(struct device *dev)
 493 {
 494         struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 495
 496         if (fan_data->ctrl)
 497                 set_fan_speed(fan_data, fan_data->resume_speed);
 498
 499         return 0;
 500 }
 501
 502 static SIMPLE_DEV_PM_OPS(gpio_fan_pm, gpio_fan_suspend, gpio_fan_resume);
 503 #define GPIO_FAN_PM     &gpio_fan_pm
 504 #else
 505 #define GPIO_FAN_PM     NULL
 506 #endif
 507
 508 static struct platform_driver gpio_fan_driver = {
 509         .probe          = gpio_fan_probe,
 510         .remove         = __devexit_p(gpio_fan_remove),
 511         .driver = {
 512                 .name   = "gpio-fan",
 513                 .pm     = GPIO_FAN_PM,
 514         },
 515 };
 516
 517 module_platform_driver(gpio_fan_driver);
 518
 519 MODULE_AUTHOR("Simon Guinot <sguinot@lacie.com>");
 520 MODULE_DESCRIPTION("GPIO FAN driver");
 521 MODULE_LICENSE("GPL");
 522 MODULE_ALIAS("platform:gpio-fan");