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 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"); 559