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 err = device_create_file(&pdev->dev, &dev_attr_fan1_alarm); 109 if (err) 110 return err; 111 112 /* 113 * If the alarm GPIO don't support interrupts, just leave 114 * without initializing the fail notification support. 115 */ 116 alarm_irq = gpio_to_irq(alarm->gpio); 117 if (alarm_irq < 0) 118 return 0; 119 120 INIT_WORK(&fan_data->alarm_work, fan_alarm_notify); 121 irq_set_irq_type(alarm_irq, IRQ_TYPE_EDGE_BOTH); 122 err = devm_request_irq(&pdev->dev, alarm_irq, fan_alarm_irq_handler, 123 IRQF_SHARED, "GPIO fan alarm", fan_data); 124 if (err) 125 goto err_free_sysfs; 126 127 return 0; 128 129 err_free_sysfs: 130 device_remove_file(&pdev->dev, &dev_attr_fan1_alarm); 131 return err; 132 } 133 134 static void fan_alarm_free(struct gpio_fan_data *fan_data) 135 { 136 struct platform_device *pdev = fan_data->pdev; 137 138 device_remove_file(&pdev->dev, &dev_attr_fan1_alarm); 139 } 140 141 /* 142 * Control GPIOs. 143 */ 144 145 /* Must be called with fan_data->lock held, except during initialization. */ 146 static void __set_fan_ctrl(struct gpio_fan_data *fan_data, int ctrl_val) 147 { 148 int i; 149 150 for (i = 0; i < fan_data->num_ctrl; i++) 151 gpio_set_value(fan_data->ctrl[i], (ctrl_val >> i) & 1); 152 } 153 154 static int __get_fan_ctrl(struct gpio_fan_data *fan_data) 155 { 156 int i; 157 int ctrl_val = 0; 158 159 for (i = 0; i < fan_data->num_ctrl; i++) { 160 int value; 161 162 value = gpio_get_value(fan_data->ctrl[i]); 163 ctrl_val |= (value << i); 164 } 165 return ctrl_val; 166 } 167 168 /* Must be called with fan_data->lock held, except during initialization. */ 169 static void set_fan_speed(struct gpio_fan_data *fan_data, int speed_index) 170 { 171 if (fan_data->speed_index == speed_index) 172 return; 173 174 __set_fan_ctrl(fan_data, fan_data->speed[speed_index].ctrl_val); 175 fan_data->speed_index = speed_index; 176 } 177 178 static int get_fan_speed_index(struct gpio_fan_data *fan_data) 179 { 180 int ctrl_val = __get_fan_ctrl(fan_data); 181 int i; 182 183 for (i = 0; i < fan_data->num_speed; i++) 184 if (fan_data->speed[i].ctrl_val == ctrl_val) 185 return i; 186 187 dev_warn(&fan_data->pdev->dev, 188 "missing speed array entry for GPIO value 0x%x\n", ctrl_val); 189 190 return -EINVAL; 191 } 192 193 static int rpm_to_speed_index(struct gpio_fan_data *fan_data, int rpm) 194 { 195 struct gpio_fan_speed *speed = fan_data->speed; 196 int i; 197 198 for (i = 0; i < fan_data->num_speed; i++) 199 if (speed[i].rpm >= rpm) 200 return i; 201 202 return fan_data->num_speed - 1; 203 } 204 205 static ssize_t show_pwm(struct device *dev, 206 struct device_attribute *attr, char *buf) 207 { 208 struct gpio_fan_data *fan_data = dev_get_drvdata(dev); 209 u8 pwm = fan_data->speed_index * 255 / (fan_data->num_speed - 1); 210 211 return sprintf(buf, "%d\n", pwm); 212 } 213 214 static ssize_t set_pwm(struct device *dev, struct device_attribute *attr, 215 const char *buf, size_t count) 216 { 217 struct gpio_fan_data *fan_data = dev_get_drvdata(dev); 218 unsigned long pwm; 219 int speed_index; 220 int ret = count; 221 222 if (kstrtoul(buf, 10, &pwm) || pwm > 255) 223 return -EINVAL; 224 225 mutex_lock(&fan_data->lock); 226 227 if (!fan_data->pwm_enable) { 228 ret = -EPERM; 229 goto exit_unlock; 230 } 231 232 speed_index = DIV_ROUND_UP(pwm * (fan_data->num_speed - 1), 255); 233 set_fan_speed(fan_data, speed_index); 234 235 exit_unlock: 236 mutex_unlock(&fan_data->lock); 237 238 return ret; 239 } 240 241 static ssize_t show_pwm_enable(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->pwm_enable); 247 } 248 249 static ssize_t set_pwm_enable(struct device *dev, struct device_attribute *attr, 250 const char *buf, size_t count) 251 { 252 struct gpio_fan_data *fan_data = dev_get_drvdata(dev); 253 unsigned long val; 254 255 if (kstrtoul(buf, 10, &val) || val > 1) 256 return -EINVAL; 257 258 if (fan_data->pwm_enable == val) 259 return count; 260 261 mutex_lock(&fan_data->lock); 262 263 fan_data->pwm_enable = val; 264 265 /* Disable manual control mode: set fan at full speed. */ 266 if (val == 0) 267 set_fan_speed(fan_data, fan_data->num_speed - 1); 268 269 mutex_unlock(&fan_data->lock); 270 271 return count; 272 } 273 274 static ssize_t show_pwm_mode(struct device *dev, 275 struct device_attribute *attr, char *buf) 276 { 277 return sprintf(buf, "0\n"); 278 } 279 280 static ssize_t show_rpm_min(struct device *dev, 281 struct device_attribute *attr, char *buf) 282 { 283 struct gpio_fan_data *fan_data = dev_get_drvdata(dev); 284 285 return sprintf(buf, "%d\n", fan_data->speed[0].rpm); 286 } 287 288 static ssize_t show_rpm_max(struct device *dev, 289 struct device_attribute *attr, char *buf) 290 { 291 struct gpio_fan_data *fan_data = dev_get_drvdata(dev); 292 293 return sprintf(buf, "%d\n", 294 fan_data->speed[fan_data->num_speed - 1].rpm); 295 } 296 297 static ssize_t show_rpm(struct device *dev, 298 struct device_attribute *attr, char *buf) 299 { 300 struct gpio_fan_data *fan_data = dev_get_drvdata(dev); 301 302 return sprintf(buf, "%d\n", fan_data->speed[fan_data->speed_index].rpm); 303 } 304 305 static ssize_t set_rpm(struct device *dev, struct device_attribute *attr, 306 const char *buf, size_t count) 307 { 308 struct gpio_fan_data *fan_data = dev_get_drvdata(dev); 309 unsigned long rpm; 310 int ret = count; 311 312 if (kstrtoul(buf, 10, &rpm)) 313 return -EINVAL; 314 315 mutex_lock(&fan_data->lock); 316 317 if (!fan_data->pwm_enable) { 318 ret = -EPERM; 319 goto exit_unlock; 320 } 321 322 set_fan_speed(fan_data, rpm_to_speed_index(fan_data, rpm)); 323 324 exit_unlock: 325 mutex_unlock(&fan_data->lock); 326 327 return ret; 328 } 329 330 static DEVICE_ATTR(pwm1, S_IRUGO | S_IWUSR, show_pwm, set_pwm); 331 static DEVICE_ATTR(pwm1_enable, S_IRUGO | S_IWUSR, 332 show_pwm_enable, set_pwm_enable); 333 static DEVICE_ATTR(pwm1_mode, S_IRUGO, show_pwm_mode, NULL); 334 static DEVICE_ATTR(fan1_min, S_IRUGO, show_rpm_min, NULL); 335 static DEVICE_ATTR(fan1_max, S_IRUGO, show_rpm_max, NULL); 336 static DEVICE_ATTR(fan1_input, S_IRUGO, show_rpm, NULL); 337 static DEVICE_ATTR(fan1_target, S_IRUGO | S_IWUSR, show_rpm, set_rpm); 338 339 static struct attribute *gpio_fan_ctrl_attributes[] = { 340 &dev_attr_pwm1.attr, 341 &dev_attr_pwm1_enable.attr, 342 &dev_attr_pwm1_mode.attr, 343 &dev_attr_fan1_input.attr, 344 &dev_attr_fan1_target.attr, 345 &dev_attr_fan1_min.attr, 346 &dev_attr_fan1_max.attr, 347 NULL 348 }; 349 350 static const struct attribute_group gpio_fan_ctrl_group = { 351 .attrs = gpio_fan_ctrl_attributes, 352 }; 353 354 static int fan_ctrl_init(struct gpio_fan_data *fan_data, 355 struct gpio_fan_platform_data *pdata) 356 { 357 struct platform_device *pdev = fan_data->pdev; 358 int num_ctrl = pdata->num_ctrl; 359 unsigned *ctrl = pdata->ctrl; 360 int i, err; 361 362 for (i = 0; i < num_ctrl; i++) { 363 err = devm_gpio_request(&pdev->dev, ctrl[i], 364 "GPIO fan control"); 365 if (err) 366 return err; 367 368 err = gpio_direction_output(ctrl[i], gpio_get_value(ctrl[i])); 369 if (err) 370 return err; 371 } 372 373 fan_data->num_ctrl = num_ctrl; 374 fan_data->ctrl = ctrl; 375 fan_data->num_speed = pdata->num_speed; 376 fan_data->speed = pdata->speed; 377 fan_data->pwm_enable = true; /* Enable manual fan speed control. */ 378 fan_data->speed_index = get_fan_speed_index(fan_data); 379 if (fan_data->speed_index < 0) 380 return -ENODEV; 381 382 err = sysfs_create_group(&pdev->dev.kobj, &gpio_fan_ctrl_group); 383 return err; 384 } 385 386 static void fan_ctrl_free(struct gpio_fan_data *fan_data) 387 { 388 struct platform_device *pdev = fan_data->pdev; 389 390 sysfs_remove_group(&pdev->dev.kobj, &gpio_fan_ctrl_group); 391 } 392 393 /* 394 * Platform driver. 395 */ 396 397 static ssize_t show_name(struct device *dev, 398 struct device_attribute *attr, char *buf) 399 { 400 return sprintf(buf, "gpio-fan\n"); 401 } 402 403 static DEVICE_ATTR(name, S_IRUGO, show_name, NULL); 404 405 406 #ifdef CONFIG_OF_GPIO 407 /* 408 * Translate OpenFirmware node properties into platform_data 409 */ 410 static int gpio_fan_get_of_pdata(struct device *dev, 411 struct gpio_fan_platform_data *pdata) 412 { 413 struct device_node *node; 414 struct gpio_fan_speed *speed; 415 unsigned *ctrl; 416 unsigned i; 417 u32 u; 418 struct property *prop; 419 const __be32 *p; 420 421 node = dev->of_node; 422 423 /* Fill GPIO pin array */ 424 pdata->num_ctrl = of_gpio_count(node); 425 if (!pdata->num_ctrl) { 426 dev_err(dev, "gpios DT property empty / missing"); 427 return -ENODEV; 428 } 429 ctrl = devm_kzalloc(dev, pdata->num_ctrl * sizeof(unsigned), 430 GFP_KERNEL); 431 if (!ctrl) 432 return -ENOMEM; 433 for (i = 0; i < pdata->num_ctrl; i++) { 434 int val; 435 436 val = of_get_gpio(node, i); 437 if (val < 0) 438 return val; 439 ctrl[i] = val; 440 } 441 pdata->ctrl = ctrl; 442 443 /* Get number of RPM/ctrl_val pairs in speed map */ 444 prop = of_find_property(node, "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 pdata->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_kzalloc(dev, 462 pdata->num_speed * sizeof(struct gpio_fan_speed), 463 GFP_KERNEL); 464 if (!speed) 465 return -ENOMEM; 466 p = NULL; 467 for (i = 0; i < pdata->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 pdata->speed = speed; 478 479 /* Alarm GPIO if one exists */ 480 if (of_gpio_named_count(node, "alarm-gpios")) { 481 struct gpio_fan_alarm *alarm; 482 int val; 483 enum of_gpio_flags flags; 484 485 alarm = devm_kzalloc(dev, sizeof(struct gpio_fan_alarm), 486 GFP_KERNEL); 487 if (!alarm) 488 return -ENOMEM; 489 490 val = of_get_named_gpio_flags(node, "alarm-gpios", 0, &flags); 491 if (val < 0) 492 return val; 493 alarm->gpio = val; 494 alarm->active_low = flags & OF_GPIO_ACTIVE_LOW; 495 496 pdata->alarm = alarm; 497 } 498 499 return 0; 500 } 501 502 static struct of_device_id of_gpio_fan_match[] = { 503 { .compatible = "gpio-fan", }, 504 {}, 505 }; 506 #endif /* CONFIG_OF_GPIO */ 507 508 static int gpio_fan_probe(struct platform_device *pdev) 509 { 510 int err; 511 struct gpio_fan_data *fan_data; 512 struct gpio_fan_platform_data *pdata = pdev->dev.platform_data; 513 514 #ifdef CONFIG_OF_GPIO 515 if (!pdata) { 516 pdata = devm_kzalloc(&pdev->dev, 517 sizeof(struct gpio_fan_platform_data), 518 GFP_KERNEL); 519 if (!pdata) 520 return -ENOMEM; 521 522 err = gpio_fan_get_of_pdata(&pdev->dev, pdata); 523 if (err) 524 return err; 525 } 526 #else /* CONFIG_OF_GPIO */ 527 if (!pdata) 528 return -EINVAL; 529 #endif /* CONFIG_OF_GPIO */ 530 531 fan_data = devm_kzalloc(&pdev->dev, sizeof(struct gpio_fan_data), 532 GFP_KERNEL); 533 if (!fan_data) 534 return -ENOMEM; 535 536 fan_data->pdev = pdev; 537 platform_set_drvdata(pdev, fan_data); 538 mutex_init(&fan_data->lock); 539 540 /* Configure alarm GPIO if available. */ 541 if (pdata->alarm) { 542 err = fan_alarm_init(fan_data, pdata->alarm); 543 if (err) 544 return err; 545 } 546 547 /* Configure control GPIOs if available. */ 548 if (pdata->ctrl && pdata->num_ctrl > 0) { 549 if (!pdata->speed || pdata->num_speed <= 1) { 550 err = -EINVAL; 551 goto err_free_alarm; 552 } 553 err = fan_ctrl_init(fan_data, pdata); 554 if (err) 555 goto err_free_alarm; 556 } 557 558 err = device_create_file(&pdev->dev, &dev_attr_name); 559 if (err) 560 goto err_free_ctrl; 561 562 /* Make this driver part of hwmon class. */ 563 fan_data->hwmon_dev = hwmon_device_register(&pdev->dev); 564 if (IS_ERR(fan_data->hwmon_dev)) { 565 err = PTR_ERR(fan_data->hwmon_dev); 566 goto err_remove_name; 567 } 568 569 dev_info(&pdev->dev, "GPIO fan initialized\n"); 570 571 return 0; 572 573 err_remove_name: 574 device_remove_file(&pdev->dev, &dev_attr_name); 575 err_free_ctrl: 576 if (fan_data->ctrl) 577 fan_ctrl_free(fan_data); 578 err_free_alarm: 579 if (fan_data->alarm) 580 fan_alarm_free(fan_data); 581 return err; 582 } 583 584 static int gpio_fan_remove(struct platform_device *pdev) 585 { 586 struct gpio_fan_data *fan_data = platform_get_drvdata(pdev); 587 588 hwmon_device_unregister(fan_data->hwmon_dev); 589 device_remove_file(&pdev->dev, &dev_attr_name); 590 if (fan_data->alarm) 591 fan_alarm_free(fan_data); 592 if (fan_data->ctrl) 593 fan_ctrl_free(fan_data); 594 595 return 0; 596 } 597 598 #ifdef CONFIG_PM_SLEEP 599 static int gpio_fan_suspend(struct device *dev) 600 { 601 struct gpio_fan_data *fan_data = dev_get_drvdata(dev); 602 603 if (fan_data->ctrl) { 604 fan_data->resume_speed = fan_data->speed_index; 605 set_fan_speed(fan_data, 0); 606 } 607 608 return 0; 609 } 610 611 static int gpio_fan_resume(struct device *dev) 612 { 613 struct gpio_fan_data *fan_data = dev_get_drvdata(dev); 614 615 if (fan_data->ctrl) 616 set_fan_speed(fan_data, fan_data->resume_speed); 617 618 return 0; 619 } 620 621 static SIMPLE_DEV_PM_OPS(gpio_fan_pm, gpio_fan_suspend, gpio_fan_resume); 622 #define GPIO_FAN_PM &gpio_fan_pm 623 #else 624 #define GPIO_FAN_PM NULL 625 #endif 626 627 static struct platform_driver gpio_fan_driver = { 628 .probe = gpio_fan_probe, 629 .remove = gpio_fan_remove, 630 .driver = { 631 .name = "gpio-fan", 632 .pm = GPIO_FAN_PM, 633 #ifdef CONFIG_OF_GPIO 634 .of_match_table = of_match_ptr(of_gpio_fan_match), 635 #endif 636 }, 637 }; 638 639 module_platform_driver(gpio_fan_driver); 640 641 MODULE_AUTHOR("Simon Guinot <sguinot@lacie.com>"); 642 MODULE_DESCRIPTION("GPIO FAN driver"); 643 MODULE_LICENSE("GPL"); 644 MODULE_ALIAS("platform:gpio-fan"); 645