1// SPDX-License-Identifier: GPL-2.0-or-later 2/* 3 * gpio-fan.c - Hwmon driver for fans connected to GPIO lines. 4 * 5 * Copyright (C) 2010 LaCie 6 * 7 * Author: Simon Guinot <sguinot@lacie.com> 8 */ 9 10#include <linux/module.h> 11#include <linux/init.h> 12#include <linux/slab.h> 13#include <linux/interrupt.h> 14#include <linux/irq.h> 15#include <linux/platform_device.h> 16#include <linux/err.h> 17#include <linux/kstrtox.h> 18#include <linux/mutex.h> 19#include <linux/hwmon.h> 20#include <linux/gpio/consumer.h> 21#include <linux/of.h> 22#include <linux/of_platform.h> 23#include <linux/thermal.h> 24 25struct gpio_fan_speed { 26 int rpm; 27 int ctrl_val; 28}; 29 30struct gpio_fan_data { 31 struct device *dev; 32 struct device *hwmon_dev; 33 /* Cooling device if any */ 34 struct thermal_cooling_device *cdev; 35 struct mutex lock; /* lock GPIOs operations. */ 36 int num_gpios; 37 struct gpio_desc **gpios; 38 int num_speed; 39 struct gpio_fan_speed *speed; 40 int speed_index; 41 int resume_speed; 42 bool pwm_enable; 43 struct gpio_desc *alarm_gpio; 44 struct work_struct alarm_work; 45}; 46 47/* 48 * Alarm GPIO. 49 */ 50 51static void fan_alarm_notify(struct work_struct *ws) 52{ 53 struct gpio_fan_data *fan_data = 54 container_of(ws, struct gpio_fan_data, alarm_work); 55 56 sysfs_notify(&fan_data->hwmon_dev->kobj, NULL, "fan1_alarm"); 57 kobject_uevent(&fan_data->hwmon_dev->kobj, KOBJ_CHANGE); 58} 59 60static irqreturn_t fan_alarm_irq_handler(int irq, void *dev_id) 61{ 62 struct gpio_fan_data *fan_data = dev_id; 63 64 schedule_work(&fan_data->alarm_work); 65 66 return IRQ_NONE; 67} 68 69static ssize_t fan1_alarm_show(struct device *dev, 70 struct device_attribute *attr, char *buf) 71{ 72 struct gpio_fan_data *fan_data = dev_get_drvdata(dev); 73 74 return sprintf(buf, "%d\n", 75 gpiod_get_value_cansleep(fan_data->alarm_gpio)); 76} 77 78static DEVICE_ATTR_RO(fan1_alarm); 79 80static int fan_alarm_init(struct gpio_fan_data *fan_data) 81{ 82 int alarm_irq; 83 struct device *dev = fan_data->dev; 84 85 /* 86 * If the alarm GPIO don't support interrupts, just leave 87 * without initializing the fail notification support. 88 */ 89 alarm_irq = gpiod_to_irq(fan_data->alarm_gpio); 90 if (alarm_irq <= 0) 91 return 0; 92 93 INIT_WORK(&fan_data->alarm_work, fan_alarm_notify); 94 irq_set_irq_type(alarm_irq, IRQ_TYPE_EDGE_BOTH); 95 return devm_request_irq(dev, alarm_irq, fan_alarm_irq_handler, 96 IRQF_SHARED, "GPIO fan alarm", fan_data); 97} 98 99/* 100 * Control GPIOs. 101 */ 102 103/* Must be called with fan_data->lock held, except during initialization. */ 104static void __set_fan_ctrl(struct gpio_fan_data *fan_data, int ctrl_val) 105{ 106 int i; 107 108 for (i = 0; i < fan_data->num_gpios; i++) 109 gpiod_set_value_cansleep(fan_data->gpios[i], 110 (ctrl_val >> i) & 1); 111} 112 113static int __get_fan_ctrl(struct gpio_fan_data *fan_data) 114{ 115 int i; 116 int ctrl_val = 0; 117 118 for (i = 0; i < fan_data->num_gpios; i++) { 119 int value; 120 121 value = gpiod_get_value_cansleep(fan_data->gpios[i]); 122 ctrl_val |= (value << i); 123 } 124 return ctrl_val; 125} 126 127/* Must be called with fan_data->lock held, except during initialization. */ 128static void set_fan_speed(struct gpio_fan_data *fan_data, int speed_index) 129{ 130 if (fan_data->speed_index == speed_index) 131 return; 132 133 __set_fan_ctrl(fan_data, fan_data->speed[speed_index].ctrl_val); 134 fan_data->speed_index = speed_index; 135} 136 137static int get_fan_speed_index(struct gpio_fan_data *fan_data) 138{ 139 int ctrl_val = __get_fan_ctrl(fan_data); 140 int i; 141 142 for (i = 0; i < fan_data->num_speed; i++) 143 if (fan_data->speed[i].ctrl_val == ctrl_val) 144 return i; 145 146 dev_warn(fan_data->dev, 147 "missing speed array entry for GPIO value 0x%x\n", ctrl_val); 148 149 return -ENODEV; 150} 151 152static int rpm_to_speed_index(struct gpio_fan_data *fan_data, unsigned long rpm) 153{ 154 struct gpio_fan_speed *speed = fan_data->speed; 155 int i; 156 157 for (i = 0; i < fan_data->num_speed; i++) 158 if (speed[i].rpm >= rpm) 159 return i; 160 161 return fan_data->num_speed - 1; 162} 163 164static ssize_t pwm1_show(struct device *dev, struct device_attribute *attr, 165 char *buf) 166{ 167 struct gpio_fan_data *fan_data = dev_get_drvdata(dev); 168 u8 pwm = fan_data->speed_index * 255 / (fan_data->num_speed - 1); 169 170 return sprintf(buf, "%d\n", pwm); 171} 172 173static ssize_t pwm1_store(struct device *dev, struct device_attribute *attr, 174 const char *buf, size_t count) 175{ 176 struct gpio_fan_data *fan_data = dev_get_drvdata(dev); 177 unsigned long pwm; 178 int speed_index; 179 int ret = count; 180 181 if (kstrtoul(buf, 10, &pwm) || pwm > 255) 182 return -EINVAL; 183 184 mutex_lock(&fan_data->lock); 185 186 if (!fan_data->pwm_enable) { 187 ret = -EPERM; 188 goto exit_unlock; 189 } 190 191 speed_index = DIV_ROUND_UP(pwm * (fan_data->num_speed - 1), 255); 192 set_fan_speed(fan_data, speed_index); 193 194exit_unlock: 195 mutex_unlock(&fan_data->lock); 196 197 return ret; 198} 199 200static ssize_t pwm1_enable_show(struct device *dev, 201 struct device_attribute *attr, char *buf) 202{ 203 struct gpio_fan_data *fan_data = dev_get_drvdata(dev); 204 205 return sprintf(buf, "%d\n", fan_data->pwm_enable); 206} 207 208static ssize_t pwm1_enable_store(struct device *dev, 209 struct device_attribute *attr, 210 const char *buf, size_t count) 211{ 212 struct gpio_fan_data *fan_data = dev_get_drvdata(dev); 213 unsigned long val; 214 215 if (kstrtoul(buf, 10, &val) || val > 1) 216 return -EINVAL; 217 218 if (fan_data->pwm_enable == val) 219 return count; 220 221 mutex_lock(&fan_data->lock); 222 223 fan_data->pwm_enable = val; 224 225 /* Disable manual control mode: set fan at full speed. */ 226 if (val == 0) 227 set_fan_speed(fan_data, fan_data->num_speed - 1); 228 229 mutex_unlock(&fan_data->lock); 230 231 return count; 232} 233 234static ssize_t pwm1_mode_show(struct device *dev, 235 struct device_attribute *attr, char *buf) 236{ 237 return sprintf(buf, "0\n"); 238} 239 240static ssize_t fan1_min_show(struct device *dev, 241 struct device_attribute *attr, char *buf) 242{ 243 struct gpio_fan_data *fan_data = dev_get_drvdata(dev); 244 245 return sprintf(buf, "%d\n", fan_data->speed[0].rpm); 246} 247 248static ssize_t fan1_max_show(struct device *dev, 249 struct device_attribute *attr, char *buf) 250{ 251 struct gpio_fan_data *fan_data = dev_get_drvdata(dev); 252 253 return sprintf(buf, "%d\n", 254 fan_data->speed[fan_data->num_speed - 1].rpm); 255} 256 257static ssize_t fan1_input_show(struct device *dev, 258 struct device_attribute *attr, char *buf) 259{ 260 struct gpio_fan_data *fan_data = dev_get_drvdata(dev); 261 262 return sprintf(buf, "%d\n", fan_data->speed[fan_data->speed_index].rpm); 263} 264 265static ssize_t set_rpm(struct device *dev, struct device_attribute *attr, 266 const char *buf, size_t count) 267{ 268 struct gpio_fan_data *fan_data = dev_get_drvdata(dev); 269 unsigned long rpm; 270 int ret = count; 271 272 if (kstrtoul(buf, 10, &rpm)) 273 return -EINVAL; 274 275 mutex_lock(&fan_data->lock); 276 277 if (!fan_data->pwm_enable) { 278 ret = -EPERM; 279 goto exit_unlock; 280 } 281 282 set_fan_speed(fan_data, rpm_to_speed_index(fan_data, rpm)); 283 284exit_unlock: 285 mutex_unlock(&fan_data->lock); 286 287 return ret; 288} 289 290static DEVICE_ATTR_RW(pwm1); 291static DEVICE_ATTR_RW(pwm1_enable); 292static DEVICE_ATTR_RO(pwm1_mode); 293static DEVICE_ATTR_RO(fan1_min); 294static DEVICE_ATTR_RO(fan1_max); 295static DEVICE_ATTR_RO(fan1_input); 296static DEVICE_ATTR(fan1_target, 0644, fan1_input_show, set_rpm); 297 298static umode_t gpio_fan_is_visible(struct kobject *kobj, 299 struct attribute *attr, int index) 300{ 301 struct device *dev = kobj_to_dev(kobj); 302 struct gpio_fan_data *data = dev_get_drvdata(dev); 303 304 if (index == 0 && !data->alarm_gpio) 305 return 0; 306 if (index > 0 && !data->gpios) 307 return 0; 308 309 return attr->mode; 310} 311 312static struct attribute *gpio_fan_attributes[] = { 313 &dev_attr_fan1_alarm.attr, /* 0 */ 314 &dev_attr_pwm1.attr, /* 1 */ 315 &dev_attr_pwm1_enable.attr, 316 &dev_attr_pwm1_mode.attr, 317 &dev_attr_fan1_input.attr, 318 &dev_attr_fan1_target.attr, 319 &dev_attr_fan1_min.attr, 320 &dev_attr_fan1_max.attr, 321 NULL 322}; 323 324static const struct attribute_group gpio_fan_group = { 325 .attrs = gpio_fan_attributes, 326 .is_visible = gpio_fan_is_visible, 327}; 328 329static const struct attribute_group *gpio_fan_groups[] = { 330 &gpio_fan_group, 331 NULL 332}; 333 334static int fan_ctrl_init(struct gpio_fan_data *fan_data) 335{ 336 int num_gpios = fan_data->num_gpios; 337 struct gpio_desc **gpios = fan_data->gpios; 338 int i, err; 339 340 for (i = 0; i < num_gpios; i++) { 341 /* 342 * The GPIO descriptors were retrieved with GPIOD_ASIS so here 343 * we set the GPIO into output mode, carefully preserving the 344 * current value by setting it to whatever it is already set 345 * (no surprise changes in default fan speed). 346 */ 347 err = gpiod_direction_output(gpios[i], 348 gpiod_get_value_cansleep(gpios[i])); 349 if (err) 350 return err; 351 } 352 353 fan_data->pwm_enable = true; /* Enable manual fan speed control. */ 354 fan_data->speed_index = get_fan_speed_index(fan_data); 355 if (fan_data->speed_index < 0) 356 return fan_data->speed_index; 357 358 return 0; 359} 360 361static int gpio_fan_get_max_state(struct thermal_cooling_device *cdev, 362 unsigned long *state) 363{ 364 struct gpio_fan_data *fan_data = cdev->devdata; 365 366 if (!fan_data) 367 return -EINVAL; 368 369 *state = fan_data->num_speed - 1; 370 return 0; 371} 372 373static int gpio_fan_get_cur_state(struct thermal_cooling_device *cdev, 374 unsigned long *state) 375{ 376 struct gpio_fan_data *fan_data = cdev->devdata; 377 378 if (!fan_data) 379 return -EINVAL; 380 381 *state = fan_data->speed_index; 382 return 0; 383} 384 385static int gpio_fan_set_cur_state(struct thermal_cooling_device *cdev, 386 unsigned long state) 387{ 388 struct gpio_fan_data *fan_data = cdev->devdata; 389 390 if (!fan_data) 391 return -EINVAL; 392 393 if (state >= fan_data->num_speed) 394 return -EINVAL; 395 396 set_fan_speed(fan_data, state); 397 return 0; 398} 399 400static const struct thermal_cooling_device_ops gpio_fan_cool_ops = { 401 .get_max_state = gpio_fan_get_max_state, 402 .get_cur_state = gpio_fan_get_cur_state, 403 .set_cur_state = gpio_fan_set_cur_state, 404}; 405 406/* 407 * Translate OpenFirmware node properties into platform_data 408 */ 409static int gpio_fan_get_of_data(struct gpio_fan_data *fan_data) 410{ 411 struct gpio_fan_speed *speed; 412 struct device *dev = fan_data->dev; 413 struct device_node *np = dev->of_node; 414 struct gpio_desc **gpios; 415 unsigned i; 416 u32 u; 417 struct property *prop; 418 const __be32 *p; 419 420 /* Alarm GPIO if one exists */ 421 fan_data->alarm_gpio = devm_gpiod_get_optional(dev, "alarm", GPIOD_IN); 422 if (IS_ERR(fan_data->alarm_gpio)) 423 return PTR_ERR(fan_data->alarm_gpio); 424 425 /* Fill GPIO pin array */ 426 fan_data->num_gpios = gpiod_count(dev, NULL); 427 if (fan_data->num_gpios <= 0) { 428 if (fan_data->alarm_gpio) 429 return 0; 430 dev_err(dev, "DT properties empty / missing"); 431 return -ENODEV; 432 } 433 gpios = devm_kcalloc(dev, 434 fan_data->num_gpios, sizeof(struct gpio_desc *), 435 GFP_KERNEL); 436 if (!gpios) 437 return -ENOMEM; 438 for (i = 0; i < fan_data->num_gpios; i++) { 439 gpios[i] = devm_gpiod_get_index(dev, NULL, i, GPIOD_ASIS); 440 if (IS_ERR(gpios[i])) 441 return PTR_ERR(gpios[i]); 442 } 443 fan_data->gpios = gpios; 444 445 /* Get number of RPM/ctrl_val pairs in speed map */ 446 prop = of_find_property(np, "gpio-fan,speed-map", &i); 447 if (!prop) { 448 dev_err(dev, "gpio-fan,speed-map DT property missing"); 449 return -ENODEV; 450 } 451 i = i / sizeof(u32); 452 if (i == 0 || i & 1) { 453 dev_err(dev, "gpio-fan,speed-map contains zero/odd number of entries"); 454 return -ENODEV; 455 } 456 fan_data->num_speed = i / 2; 457 458 /* 459 * Populate speed map 460 * Speed map is in the form <RPM ctrl_val RPM ctrl_val ...> 461 * this needs splitting into pairs to create gpio_fan_speed structs 462 */ 463 speed = devm_kcalloc(dev, 464 fan_data->num_speed, sizeof(struct gpio_fan_speed), 465 GFP_KERNEL); 466 if (!speed) 467 return -ENOMEM; 468 p = NULL; 469 for (i = 0; i < fan_data->num_speed; i++) { 470 p = of_prop_next_u32(prop, p, &u); 471 if (!p) 472 return -ENODEV; 473 speed[i].rpm = u; 474 p = of_prop_next_u32(prop, p, &u); 475 if (!p) 476 return -ENODEV; 477 speed[i].ctrl_val = u; 478 } 479 fan_data->speed = speed; 480 481 return 0; 482} 483 484static const struct of_device_id of_gpio_fan_match[] = { 485 { .compatible = "gpio-fan", }, 486 {}, 487}; 488MODULE_DEVICE_TABLE(of, of_gpio_fan_match); 489 490static void gpio_fan_stop(void *data) 491{ 492 set_fan_speed(data, 0); 493} 494 495static int gpio_fan_probe(struct platform_device *pdev) 496{ 497 int err; 498 struct gpio_fan_data *fan_data; 499 struct device *dev = &pdev->dev; 500 struct device_node *np = dev->of_node; 501 502 fan_data = devm_kzalloc(dev, sizeof(struct gpio_fan_data), 503 GFP_KERNEL); 504 if (!fan_data) 505 return -ENOMEM; 506 507 fan_data->dev = dev; 508 err = gpio_fan_get_of_data(fan_data); 509 if (err) 510 return err; 511 512 platform_set_drvdata(pdev, fan_data); 513 mutex_init(&fan_data->lock); 514 515 /* Configure control GPIOs if available. */ 516 if (fan_data->gpios && fan_data->num_gpios > 0) { 517 if (!fan_data->speed || fan_data->num_speed <= 1) 518 return -EINVAL; 519 err = fan_ctrl_init(fan_data); 520 if (err) 521 return err; 522 err = devm_add_action_or_reset(dev, gpio_fan_stop, fan_data); 523 if (err) 524 return err; 525 } 526 527 /* Make this driver part of hwmon class. */ 528 fan_data->hwmon_dev = 529 devm_hwmon_device_register_with_groups(dev, 530 "gpio_fan", fan_data, 531 gpio_fan_groups); 532 if (IS_ERR(fan_data->hwmon_dev)) 533 return PTR_ERR(fan_data->hwmon_dev); 534 535 /* Configure alarm GPIO if available. */ 536 if (fan_data->alarm_gpio) { 537 err = fan_alarm_init(fan_data); 538 if (err) 539 return err; 540 } 541 542 /* Optional cooling device register for Device tree platforms */ 543 fan_data->cdev = devm_thermal_of_cooling_device_register(dev, np, 544 "gpio-fan", fan_data, &gpio_fan_cool_ops); 545 546 dev_info(dev, "GPIO fan initialized\n"); 547 548 return 0; 549} 550 551static void gpio_fan_shutdown(struct platform_device *pdev) 552{ 553 struct gpio_fan_data *fan_data = platform_get_drvdata(pdev); 554 555 if (fan_data->gpios) 556 set_fan_speed(fan_data, 0); 557} 558 559static int gpio_fan_suspend(struct device *dev) 560{ 561 struct gpio_fan_data *fan_data = dev_get_drvdata(dev); 562 563 if (fan_data->gpios) { 564 fan_data->resume_speed = fan_data->speed_index; 565 set_fan_speed(fan_data, 0); 566 } 567 568 return 0; 569} 570 571static int gpio_fan_resume(struct device *dev) 572{ 573 struct gpio_fan_data *fan_data = dev_get_drvdata(dev); 574 575 if (fan_data->gpios) 576 set_fan_speed(fan_data, fan_data->resume_speed); 577 578 return 0; 579} 580 581static DEFINE_SIMPLE_DEV_PM_OPS(gpio_fan_pm, gpio_fan_suspend, gpio_fan_resume); 582 583static struct platform_driver gpio_fan_driver = { 584 .probe = gpio_fan_probe, 585 .shutdown = gpio_fan_shutdown, 586 .driver = { 587 .name = "gpio-fan", 588 .pm = pm_sleep_ptr(&gpio_fan_pm), 589 .of_match_table = of_gpio_fan_match, 590 }, 591}; 592 593module_platform_driver(gpio_fan_driver); 594 595MODULE_AUTHOR("Simon Guinot <sguinot@lacie.com>"); 596MODULE_DESCRIPTION("GPIO FAN driver"); 597MODULE_LICENSE("GPL"); 598MODULE_ALIAS("platform:gpio-fan"); 599