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/consumer.h> 33 #include <linux/of.h> 34 #include <linux/of_platform.h> 35 #include <linux/thermal.h> 36 37 struct gpio_fan_speed { 38 int rpm; 39 int ctrl_val; 40 }; 41 42 struct gpio_fan_data { 43 struct device *dev; 44 struct device *hwmon_dev; 45 /* Cooling device if any */ 46 struct thermal_cooling_device *cdev; 47 struct mutex lock; /* lock GPIOs operations. */ 48 int num_gpios; 49 struct gpio_desc **gpios; 50 int num_speed; 51 struct gpio_fan_speed *speed; 52 int speed_index; 53 #ifdef CONFIG_PM_SLEEP 54 int resume_speed; 55 #endif 56 bool pwm_enable; 57 struct gpio_desc *alarm_gpio; 58 struct work_struct alarm_work; 59 }; 60 61 /* 62 * Alarm GPIO. 63 */ 64 65 static void fan_alarm_notify(struct work_struct *ws) 66 { 67 struct gpio_fan_data *fan_data = 68 container_of(ws, struct gpio_fan_data, alarm_work); 69 70 sysfs_notify(&fan_data->dev->kobj, NULL, "fan1_alarm"); 71 kobject_uevent(&fan_data->dev->kobj, KOBJ_CHANGE); 72 } 73 74 static irqreturn_t fan_alarm_irq_handler(int irq, void *dev_id) 75 { 76 struct gpio_fan_data *fan_data = dev_id; 77 78 schedule_work(&fan_data->alarm_work); 79 80 return IRQ_NONE; 81 } 82 83 static ssize_t fan1_alarm_show(struct device *dev, 84 struct device_attribute *attr, char *buf) 85 { 86 struct gpio_fan_data *fan_data = dev_get_drvdata(dev); 87 88 return sprintf(buf, "%d\n", 89 gpiod_get_value_cansleep(fan_data->alarm_gpio)); 90 } 91 92 static DEVICE_ATTR_RO(fan1_alarm); 93 94 static int fan_alarm_init(struct gpio_fan_data *fan_data) 95 { 96 int alarm_irq; 97 struct device *dev = fan_data->dev; 98 99 /* 100 * If the alarm GPIO don't support interrupts, just leave 101 * without initializing the fail notification support. 102 */ 103 alarm_irq = gpiod_to_irq(fan_data->alarm_gpio); 104 if (alarm_irq <= 0) 105 return 0; 106 107 INIT_WORK(&fan_data->alarm_work, fan_alarm_notify); 108 irq_set_irq_type(alarm_irq, IRQ_TYPE_EDGE_BOTH); 109 return devm_request_irq(dev, alarm_irq, fan_alarm_irq_handler, 110 IRQF_SHARED, "GPIO fan alarm", fan_data); 111 } 112 113 /* 114 * Control GPIOs. 115 */ 116 117 /* Must be called with fan_data->lock held, except during initialization. */ 118 static void __set_fan_ctrl(struct gpio_fan_data *fan_data, int ctrl_val) 119 { 120 int i; 121 122 for (i = 0; i < fan_data->num_gpios; i++) 123 gpiod_set_value_cansleep(fan_data->gpios[i], 124 (ctrl_val >> i) & 1); 125 } 126 127 static int __get_fan_ctrl(struct gpio_fan_data *fan_data) 128 { 129 int i; 130 int ctrl_val = 0; 131 132 for (i = 0; i < fan_data->num_gpios; i++) { 133 int value; 134 135 value = gpiod_get_value_cansleep(fan_data->gpios[i]); 136 ctrl_val |= (value << i); 137 } 138 return ctrl_val; 139 } 140 141 /* Must be called with fan_data->lock held, except during initialization. */ 142 static void set_fan_speed(struct gpio_fan_data *fan_data, int speed_index) 143 { 144 if (fan_data->speed_index == speed_index) 145 return; 146 147 __set_fan_ctrl(fan_data, fan_data->speed[speed_index].ctrl_val); 148 fan_data->speed_index = speed_index; 149 } 150 151 static int get_fan_speed_index(struct gpio_fan_data *fan_data) 152 { 153 int ctrl_val = __get_fan_ctrl(fan_data); 154 int i; 155 156 for (i = 0; i < fan_data->num_speed; i++) 157 if (fan_data->speed[i].ctrl_val == ctrl_val) 158 return i; 159 160 dev_warn(fan_data->dev, 161 "missing speed array entry for GPIO value 0x%x\n", ctrl_val); 162 163 return -ENODEV; 164 } 165 166 static int rpm_to_speed_index(struct gpio_fan_data *fan_data, unsigned long rpm) 167 { 168 struct gpio_fan_speed *speed = fan_data->speed; 169 int i; 170 171 for (i = 0; i < fan_data->num_speed; i++) 172 if (speed[i].rpm >= rpm) 173 return i; 174 175 return fan_data->num_speed - 1; 176 } 177 178 static ssize_t pwm1_show(struct device *dev, struct device_attribute *attr, 179 char *buf) 180 { 181 struct gpio_fan_data *fan_data = dev_get_drvdata(dev); 182 u8 pwm = fan_data->speed_index * 255 / (fan_data->num_speed - 1); 183 184 return sprintf(buf, "%d\n", pwm); 185 } 186 187 static ssize_t pwm1_store(struct device *dev, struct device_attribute *attr, 188 const char *buf, size_t count) 189 { 190 struct gpio_fan_data *fan_data = dev_get_drvdata(dev); 191 unsigned long pwm; 192 int speed_index; 193 int ret = count; 194 195 if (kstrtoul(buf, 10, &pwm) || pwm > 255) 196 return -EINVAL; 197 198 mutex_lock(&fan_data->lock); 199 200 if (!fan_data->pwm_enable) { 201 ret = -EPERM; 202 goto exit_unlock; 203 } 204 205 speed_index = DIV_ROUND_UP(pwm * (fan_data->num_speed - 1), 255); 206 set_fan_speed(fan_data, speed_index); 207 208 exit_unlock: 209 mutex_unlock(&fan_data->lock); 210 211 return ret; 212 } 213 214 static ssize_t pwm1_enable_show(struct device *dev, 215 struct device_attribute *attr, char *buf) 216 { 217 struct gpio_fan_data *fan_data = dev_get_drvdata(dev); 218 219 return sprintf(buf, "%d\n", fan_data->pwm_enable); 220 } 221 222 static ssize_t pwm1_enable_store(struct device *dev, 223 struct device_attribute *attr, 224 const char *buf, size_t count) 225 { 226 struct gpio_fan_data *fan_data = dev_get_drvdata(dev); 227 unsigned long val; 228 229 if (kstrtoul(buf, 10, &val) || val > 1) 230 return -EINVAL; 231 232 if (fan_data->pwm_enable == val) 233 return count; 234 235 mutex_lock(&fan_data->lock); 236 237 fan_data->pwm_enable = val; 238 239 /* Disable manual control mode: set fan at full speed. */ 240 if (val == 0) 241 set_fan_speed(fan_data, fan_data->num_speed - 1); 242 243 mutex_unlock(&fan_data->lock); 244 245 return count; 246 } 247 248 static ssize_t pwm1_mode_show(struct device *dev, 249 struct device_attribute *attr, char *buf) 250 { 251 return sprintf(buf, "0\n"); 252 } 253 254 static ssize_t fan1_min_show(struct device *dev, 255 struct device_attribute *attr, char *buf) 256 { 257 struct gpio_fan_data *fan_data = dev_get_drvdata(dev); 258 259 return sprintf(buf, "%d\n", fan_data->speed[0].rpm); 260 } 261 262 static ssize_t fan1_max_show(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", 268 fan_data->speed[fan_data->num_speed - 1].rpm); 269 } 270 271 static ssize_t fan1_input_show(struct device *dev, 272 struct device_attribute *attr, char *buf) 273 { 274 struct gpio_fan_data *fan_data = dev_get_drvdata(dev); 275 276 return sprintf(buf, "%d\n", fan_data->speed[fan_data->speed_index].rpm); 277 } 278 279 static ssize_t set_rpm(struct device *dev, struct device_attribute *attr, 280 const char *buf, size_t count) 281 { 282 struct gpio_fan_data *fan_data = dev_get_drvdata(dev); 283 unsigned long rpm; 284 int ret = count; 285 286 if (kstrtoul(buf, 10, &rpm)) 287 return -EINVAL; 288 289 mutex_lock(&fan_data->lock); 290 291 if (!fan_data->pwm_enable) { 292 ret = -EPERM; 293 goto exit_unlock; 294 } 295 296 set_fan_speed(fan_data, rpm_to_speed_index(fan_data, rpm)); 297 298 exit_unlock: 299 mutex_unlock(&fan_data->lock); 300 301 return ret; 302 } 303 304 static DEVICE_ATTR_RW(pwm1); 305 static DEVICE_ATTR_RW(pwm1_enable); 306 static DEVICE_ATTR_RO(pwm1_mode); 307 static DEVICE_ATTR_RO(fan1_min); 308 static DEVICE_ATTR_RO(fan1_max); 309 static DEVICE_ATTR_RO(fan1_input); 310 static DEVICE_ATTR(fan1_target, 0644, fan1_input_show, set_rpm); 311 312 static umode_t gpio_fan_is_visible(struct kobject *kobj, 313 struct attribute *attr, int index) 314 { 315 struct device *dev = container_of(kobj, struct device, kobj); 316 struct gpio_fan_data *data = dev_get_drvdata(dev); 317 318 if (index == 0 && !data->alarm_gpio) 319 return 0; 320 if (index > 0 && !data->gpios) 321 return 0; 322 323 return attr->mode; 324 } 325 326 static struct attribute *gpio_fan_attributes[] = { 327 &dev_attr_fan1_alarm.attr, /* 0 */ 328 &dev_attr_pwm1.attr, /* 1 */ 329 &dev_attr_pwm1_enable.attr, 330 &dev_attr_pwm1_mode.attr, 331 &dev_attr_fan1_input.attr, 332 &dev_attr_fan1_target.attr, 333 &dev_attr_fan1_min.attr, 334 &dev_attr_fan1_max.attr, 335 NULL 336 }; 337 338 static const struct attribute_group gpio_fan_group = { 339 .attrs = gpio_fan_attributes, 340 .is_visible = gpio_fan_is_visible, 341 }; 342 343 static const struct attribute_group *gpio_fan_groups[] = { 344 &gpio_fan_group, 345 NULL 346 }; 347 348 static int fan_ctrl_init(struct gpio_fan_data *fan_data) 349 { 350 int num_gpios = fan_data->num_gpios; 351 struct gpio_desc **gpios = fan_data->gpios; 352 int i, err; 353 354 for (i = 0; i < num_gpios; i++) { 355 /* 356 * The GPIO descriptors were retrieved with GPIOD_ASIS so here 357 * we set the GPIO into output mode, carefully preserving the 358 * current value by setting it to whatever it is already set 359 * (no surprise changes in default fan speed). 360 */ 361 err = gpiod_direction_output(gpios[i], 362 gpiod_get_value_cansleep(gpios[i])); 363 if (err) 364 return err; 365 } 366 367 fan_data->pwm_enable = true; /* Enable manual fan speed control. */ 368 fan_data->speed_index = get_fan_speed_index(fan_data); 369 if (fan_data->speed_index < 0) 370 return fan_data->speed_index; 371 372 return 0; 373 } 374 375 static int gpio_fan_get_max_state(struct thermal_cooling_device *cdev, 376 unsigned long *state) 377 { 378 struct gpio_fan_data *fan_data = cdev->devdata; 379 380 if (!fan_data) 381 return -EINVAL; 382 383 *state = fan_data->num_speed - 1; 384 return 0; 385 } 386 387 static int gpio_fan_get_cur_state(struct thermal_cooling_device *cdev, 388 unsigned long *state) 389 { 390 struct gpio_fan_data *fan_data = cdev->devdata; 391 392 if (!fan_data) 393 return -EINVAL; 394 395 *state = fan_data->speed_index; 396 return 0; 397 } 398 399 static int gpio_fan_set_cur_state(struct thermal_cooling_device *cdev, 400 unsigned long state) 401 { 402 struct gpio_fan_data *fan_data = cdev->devdata; 403 404 if (!fan_data) 405 return -EINVAL; 406 407 set_fan_speed(fan_data, state); 408 return 0; 409 } 410 411 static const struct thermal_cooling_device_ops gpio_fan_cool_ops = { 412 .get_max_state = gpio_fan_get_max_state, 413 .get_cur_state = gpio_fan_get_cur_state, 414 .set_cur_state = gpio_fan_set_cur_state, 415 }; 416 417 /* 418 * Translate OpenFirmware node properties into platform_data 419 */ 420 static int gpio_fan_get_of_data(struct gpio_fan_data *fan_data) 421 { 422 struct gpio_fan_speed *speed; 423 struct device *dev = fan_data->dev; 424 struct device_node *np = dev->of_node; 425 struct gpio_desc **gpios; 426 unsigned i; 427 u32 u; 428 struct property *prop; 429 const __be32 *p; 430 431 /* Alarm GPIO if one exists */ 432 fan_data->alarm_gpio = devm_gpiod_get_optional(dev, "alarm", GPIOD_IN); 433 if (IS_ERR(fan_data->alarm_gpio)) 434 return PTR_ERR(fan_data->alarm_gpio); 435 436 /* Fill GPIO pin array */ 437 fan_data->num_gpios = gpiod_count(dev, NULL); 438 if (fan_data->num_gpios <= 0) { 439 if (fan_data->alarm_gpio) 440 return 0; 441 dev_err(dev, "DT properties empty / missing"); 442 return -ENODEV; 443 } 444 gpios = devm_kcalloc(dev, 445 fan_data->num_gpios, sizeof(struct gpio_desc *), 446 GFP_KERNEL); 447 if (!gpios) 448 return -ENOMEM; 449 for (i = 0; i < fan_data->num_gpios; i++) { 450 gpios[i] = devm_gpiod_get_index(dev, NULL, i, GPIOD_ASIS); 451 if (IS_ERR(gpios[i])) 452 return PTR_ERR(gpios[i]); 453 } 454 fan_data->gpios = gpios; 455 456 /* Get number of RPM/ctrl_val pairs in speed map */ 457 prop = of_find_property(np, "gpio-fan,speed-map", &i); 458 if (!prop) { 459 dev_err(dev, "gpio-fan,speed-map DT property missing"); 460 return -ENODEV; 461 } 462 i = i / sizeof(u32); 463 if (i == 0 || i & 1) { 464 dev_err(dev, "gpio-fan,speed-map contains zero/odd number of entries"); 465 return -ENODEV; 466 } 467 fan_data->num_speed = i / 2; 468 469 /* 470 * Populate speed map 471 * Speed map is in the form <RPM ctrl_val RPM ctrl_val ...> 472 * this needs splitting into pairs to create gpio_fan_speed structs 473 */ 474 speed = devm_kcalloc(dev, 475 fan_data->num_speed, sizeof(struct gpio_fan_speed), 476 GFP_KERNEL); 477 if (!speed) 478 return -ENOMEM; 479 p = NULL; 480 for (i = 0; i < fan_data->num_speed; i++) { 481 p = of_prop_next_u32(prop, p, &u); 482 if (!p) 483 return -ENODEV; 484 speed[i].rpm = u; 485 p = of_prop_next_u32(prop, p, &u); 486 if (!p) 487 return -ENODEV; 488 speed[i].ctrl_val = u; 489 } 490 fan_data->speed = speed; 491 492 return 0; 493 } 494 495 static const struct of_device_id of_gpio_fan_match[] = { 496 { .compatible = "gpio-fan", }, 497 {}, 498 }; 499 MODULE_DEVICE_TABLE(of, of_gpio_fan_match); 500 501 static int gpio_fan_probe(struct platform_device *pdev) 502 { 503 int err; 504 struct gpio_fan_data *fan_data; 505 struct device *dev = &pdev->dev; 506 struct device_node *np = dev->of_node; 507 508 fan_data = devm_kzalloc(dev, sizeof(struct gpio_fan_data), 509 GFP_KERNEL); 510 if (!fan_data) 511 return -ENOMEM; 512 513 fan_data->dev = dev; 514 err = gpio_fan_get_of_data(fan_data); 515 if (err) 516 return err; 517 518 platform_set_drvdata(pdev, fan_data); 519 mutex_init(&fan_data->lock); 520 521 /* Configure alarm GPIO if available. */ 522 if (fan_data->alarm_gpio) { 523 err = fan_alarm_init(fan_data); 524 if (err) 525 return err; 526 } 527 528 /* Configure control GPIOs if available. */ 529 if (fan_data->gpios && fan_data->num_gpios > 0) { 530 if (!fan_data->speed || fan_data->num_speed <= 1) 531 return -EINVAL; 532 err = fan_ctrl_init(fan_data); 533 if (err) 534 return err; 535 } 536 537 /* Make this driver part of hwmon class. */ 538 fan_data->hwmon_dev = 539 devm_hwmon_device_register_with_groups(dev, 540 "gpio_fan", fan_data, 541 gpio_fan_groups); 542 if (IS_ERR(fan_data->hwmon_dev)) 543 return PTR_ERR(fan_data->hwmon_dev); 544 545 /* Optional cooling device register for Device tree platforms */ 546 fan_data->cdev = thermal_of_cooling_device_register(np, 547 "gpio-fan", 548 fan_data, 549 &gpio_fan_cool_ops); 550 551 dev_info(dev, "GPIO fan initialized\n"); 552 553 return 0; 554 } 555 556 static int gpio_fan_remove(struct platform_device *pdev) 557 { 558 struct gpio_fan_data *fan_data = platform_get_drvdata(pdev); 559 560 if (!IS_ERR(fan_data->cdev)) 561 thermal_cooling_device_unregister(fan_data->cdev); 562 563 if (fan_data->gpios) 564 set_fan_speed(fan_data, 0); 565 566 return 0; 567 } 568 569 static void gpio_fan_shutdown(struct platform_device *pdev) 570 { 571 gpio_fan_remove(pdev); 572 } 573 574 #ifdef CONFIG_PM_SLEEP 575 static int gpio_fan_suspend(struct device *dev) 576 { 577 struct gpio_fan_data *fan_data = dev_get_drvdata(dev); 578 579 if (fan_data->gpios) { 580 fan_data->resume_speed = fan_data->speed_index; 581 set_fan_speed(fan_data, 0); 582 } 583 584 return 0; 585 } 586 587 static int gpio_fan_resume(struct device *dev) 588 { 589 struct gpio_fan_data *fan_data = dev_get_drvdata(dev); 590 591 if (fan_data->gpios) 592 set_fan_speed(fan_data, fan_data->resume_speed); 593 594 return 0; 595 } 596 597 static SIMPLE_DEV_PM_OPS(gpio_fan_pm, gpio_fan_suspend, gpio_fan_resume); 598 #define GPIO_FAN_PM (&gpio_fan_pm) 599 #else 600 #define GPIO_FAN_PM NULL 601 #endif 602 603 static struct platform_driver gpio_fan_driver = { 604 .probe = gpio_fan_probe, 605 .remove = gpio_fan_remove, 606 .shutdown = gpio_fan_shutdown, 607 .driver = { 608 .name = "gpio-fan", 609 .pm = GPIO_FAN_PM, 610 .of_match_table = of_match_ptr(of_gpio_fan_match), 611 }, 612 }; 613 614 module_platform_driver(gpio_fan_driver); 615 616 MODULE_AUTHOR("Simon Guinot <sguinot@lacie.com>"); 617 MODULE_DESCRIPTION("GPIO FAN driver"); 618 MODULE_LICENSE("GPL"); 619 MODULE_ALIAS("platform:gpio-fan"); 620