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"); 619