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/mutex.h> 18#include <linux/hwmon.h> 19#include <linux/gpio/consumer.h> 20#include <linux/of.h> 21#include <linux/of_platform.h> 22#include <linux/thermal.h> 23 24struct gpio_fan_speed { 25 int rpm; 26 int ctrl_val; 27}; 28 29struct gpio_fan_data { 30 struct device *dev; 31 struct device *hwmon_dev; 32 /* Cooling device if any */ 33 struct thermal_cooling_device *cdev; 34 struct mutex lock; /* lock GPIOs operations. */ 35 int num_gpios; 36 struct gpio_desc **gpios; 37 int num_speed; 38 struct gpio_fan_speed *speed; 39 int speed_index; 40#ifdef CONFIG_PM_SLEEP 41 int resume_speed; 42#endif 43 bool pwm_enable; 44 struct gpio_desc *alarm_gpio; 45 struct work_struct alarm_work; 46}; 47 48/* 49 * Alarm GPIO. 50 */ 51 52static void fan_alarm_notify(struct work_struct *ws) 53{ 54 struct gpio_fan_data *fan_data = 55 container_of(ws, struct gpio_fan_data, alarm_work); 56 57 sysfs_notify(&fan_data->hwmon_dev->kobj, NULL, "fan1_alarm"); 58 kobject_uevent(&fan_data->hwmon_dev->kobj, KOBJ_CHANGE); 59} 60 61static irqreturn_t fan_alarm_irq_handler(int irq, void *dev_id) 62{ 63 struct gpio_fan_data *fan_data = dev_id; 64 65 schedule_work(&fan_data->alarm_work); 66 67 return IRQ_NONE; 68} 69 70static ssize_t fan1_alarm_show(struct device *dev, 71 struct device_attribute *attr, char *buf) 72{ 73 struct gpio_fan_data *fan_data = dev_get_drvdata(dev); 74 75 return sprintf(buf, "%d\n", 76 gpiod_get_value_cansleep(fan_data->alarm_gpio)); 77} 78 79static DEVICE_ATTR_RO(fan1_alarm); 80 81static int fan_alarm_init(struct gpio_fan_data *fan_data) 82{ 83 int alarm_irq; 84 struct device *dev = fan_data->dev; 85 86 /* 87 * If the alarm GPIO don't support interrupts, just leave 88 * without initializing the fail notification support. 89 */ 90 alarm_irq = gpiod_to_irq(fan_data->alarm_gpio); 91 if (alarm_irq <= 0) 92 return 0; 93 94 INIT_WORK(&fan_data->alarm_work, fan_alarm_notify); 95 irq_set_irq_type(alarm_irq, IRQ_TYPE_EDGE_BOTH); 96 return devm_request_irq(dev, alarm_irq, fan_alarm_irq_handler, 97 IRQF_SHARED, "GPIO fan alarm", fan_data); 98} 99 100/* 101 * Control GPIOs. 102 */ 103 104/* Must be called with fan_data->lock held, except during initialization. */ 105static void __set_fan_ctrl(struct gpio_fan_data *fan_data, int ctrl_val) 106{ 107 int i; 108 109 for (i = 0; i < fan_data->num_gpios; i++) 110 gpiod_set_value_cansleep(fan_data->gpios[i], 111 (ctrl_val >> i) & 1); 112} 113 114static int __get_fan_ctrl(struct gpio_fan_data *fan_data) 115{ 116 int i; 117 int ctrl_val = 0; 118 119 for (i = 0; i < fan_data->num_gpios; i++) { 120 int value; 121 122 value = gpiod_get_value_cansleep(fan_data->gpios[i]); 123 ctrl_val |= (value << i); 124 } 125 return ctrl_val; 126} 127 128/* Must be called with fan_data->lock held, except during initialization. */ 129static void set_fan_speed(struct gpio_fan_data *fan_data, int speed_index) 130{ 131 if (fan_data->speed_index == speed_index) 132 return; 133 134 __set_fan_ctrl(fan_data, fan_data->speed[speed_index].ctrl_val); 135 fan_data->speed_index = speed_index; 136} 137 138static int get_fan_speed_index(struct gpio_fan_data *fan_data) 139{ 140 int ctrl_val = __get_fan_ctrl(fan_data); 141 int i; 142 143 for (i = 0; i < fan_data->num_speed; i++) 144 if (fan_data->speed[i].ctrl_val == ctrl_val) 145 return i; 146 147 dev_warn(fan_data->dev, 148 "missing speed array entry for GPIO value 0x%x\n", ctrl_val); 149 150 return -ENODEV; 151} 152 153static int rpm_to_speed_index(struct gpio_fan_data *fan_data, unsigned long rpm) 154{ 155 struct gpio_fan_speed *speed = fan_data->speed; 156 int i; 157 158 for (i = 0; i < fan_data->num_speed; i++) 159 if (speed[i].rpm >= rpm) 160 return i; 161 162 return fan_data->num_speed - 1; 163} 164 165static ssize_t pwm1_show(struct device *dev, struct device_attribute *attr, 166 char *buf) 167{ 168 struct gpio_fan_data *fan_data = dev_get_drvdata(dev); 169 u8 pwm = fan_data->speed_index * 255 / (fan_data->num_speed - 1); 170 171 return sprintf(buf, "%d\n", pwm); 172} 173 174static ssize_t pwm1_store(struct device *dev, struct device_attribute *attr, 175 const char *buf, size_t count) 176{ 177 struct gpio_fan_data *fan_data = dev_get_drvdata(dev); 178 unsigned long pwm; 179 int speed_index; 180 int ret = count; 181 182 if (kstrtoul(buf, 10, &pwm) || pwm > 255) 183 return -EINVAL; 184 185 mutex_lock(&fan_data->lock); 186 187 if (!fan_data->pwm_enable) { 188 ret = -EPERM; 189 goto exit_unlock; 190 } 191 192 speed_index = DIV_ROUND_UP(pwm * (fan_data->num_speed - 1), 255); 193 set_fan_speed(fan_data, speed_index); 194 195exit_unlock: 196 mutex_unlock(&fan_data->lock); 197 198 return ret; 199} 200 201static ssize_t pwm1_enable_show(struct device *dev, 202 struct device_attribute *attr, char *buf) 203{ 204 struct gpio_fan_data *fan_data = dev_get_drvdata(dev); 205 206 return sprintf(buf, "%d\n", fan_data->pwm_enable); 207} 208 209static ssize_t pwm1_enable_store(struct device *dev, 210 struct device_attribute *attr, 211 const char *buf, size_t count) 212{ 213 struct gpio_fan_data *fan_data = dev_get_drvdata(dev); 214 unsigned long val; 215 216 if (kstrtoul(buf, 10, &val) || val > 1) 217 return -EINVAL; 218 219 if (fan_data->pwm_enable == val) 220 return count; 221 222 mutex_lock(&fan_data->lock); 223 224 fan_data->pwm_enable = val; 225 226 /* Disable manual control mode: set fan at full speed. */ 227 if (val == 0) 228 set_fan_speed(fan_data, fan_data->num_speed - 1); 229 230 mutex_unlock(&fan_data->lock); 231 232 return count; 233} 234 235static ssize_t pwm1_mode_show(struct device *dev, 236 struct device_attribute *attr, char *buf) 237{ 238 return sprintf(buf, "0\n"); 239} 240 241static ssize_t fan1_min_show(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->speed[0].rpm); 247} 248 249static ssize_t fan1_max_show(struct device *dev, 250 struct device_attribute *attr, char *buf) 251{ 252 struct gpio_fan_data *fan_data = dev_get_drvdata(dev); 253 254 return sprintf(buf, "%d\n", 255 fan_data->speed[fan_data->num_speed - 1].rpm); 256} 257 258static ssize_t fan1_input_show(struct device *dev, 259 struct device_attribute *attr, char *buf) 260{ 261 struct gpio_fan_data *fan_data = dev_get_drvdata(dev); 262 263 return sprintf(buf, "%d\n", fan_data->speed[fan_data->speed_index].rpm); 264} 265 266static ssize_t set_rpm(struct device *dev, struct device_attribute *attr, 267 const char *buf, size_t count) 268{ 269 struct gpio_fan_data *fan_data = dev_get_drvdata(dev); 270 unsigned long rpm; 271 int ret = count; 272 273 if (kstrtoul(buf, 10, &rpm)) 274 return -EINVAL; 275 276 mutex_lock(&fan_data->lock); 277 278 if (!fan_data->pwm_enable) { 279 ret = -EPERM; 280 goto exit_unlock; 281 } 282 283 set_fan_speed(fan_data, rpm_to_speed_index(fan_data, rpm)); 284 285exit_unlock: 286 mutex_unlock(&fan_data->lock); 287 288 return ret; 289} 290 291static DEVICE_ATTR_RW(pwm1); 292static DEVICE_ATTR_RW(pwm1_enable); 293static DEVICE_ATTR_RO(pwm1_mode); 294static DEVICE_ATTR_RO(fan1_min); 295static DEVICE_ATTR_RO(fan1_max); 296static DEVICE_ATTR_RO(fan1_input); 297static DEVICE_ATTR(fan1_target, 0644, fan1_input_show, set_rpm); 298 299static umode_t gpio_fan_is_visible(struct kobject *kobj, 300 struct attribute *attr, int index) 301{ 302 struct device *dev = container_of(kobj, struct device, kobj); 303 struct gpio_fan_data *data = dev_get_drvdata(dev); 304 305 if (index == 0 && !data->alarm_gpio) 306 return 0; 307 if (index > 0 && !data->gpios) 308 return 0; 309 310 return attr->mode; 311} 312 313static struct attribute *gpio_fan_attributes[] = { 314 &dev_attr_fan1_alarm.attr, /* 0 */ 315 &dev_attr_pwm1.attr, /* 1 */ 316 &dev_attr_pwm1_enable.attr, 317 &dev_attr_pwm1_mode.attr, 318 &dev_attr_fan1_input.attr, 319 &dev_attr_fan1_target.attr, 320 &dev_attr_fan1_min.attr, 321 &dev_attr_fan1_max.attr, 322 NULL 323}; 324 325static const struct attribute_group gpio_fan_group = { 326 .attrs = gpio_fan_attributes, 327 .is_visible = gpio_fan_is_visible, 328}; 329 330static const struct attribute_group *gpio_fan_groups[] = { 331 &gpio_fan_group, 332 NULL 333}; 334 335static int fan_ctrl_init(struct gpio_fan_data *fan_data) 336{ 337 int num_gpios = fan_data->num_gpios; 338 struct gpio_desc **gpios = fan_data->gpios; 339 int i, err; 340 341 for (i = 0; i < num_gpios; i++) { 342 /* 343 * The GPIO descriptors were retrieved with GPIOD_ASIS so here 344 * we set the GPIO into output mode, carefully preserving the 345 * current value by setting it to whatever it is already set 346 * (no surprise changes in default fan speed). 347 */ 348 err = gpiod_direction_output(gpios[i], 349 gpiod_get_value_cansleep(gpios[i])); 350 if (err) 351 return err; 352 } 353 354 fan_data->pwm_enable = true; /* Enable manual fan speed control. */ 355 fan_data->speed_index = get_fan_speed_index(fan_data); 356 if (fan_data->speed_index < 0) 357 return fan_data->speed_index; 358 359 return 0; 360} 361 362static int gpio_fan_get_max_state(struct thermal_cooling_device *cdev, 363 unsigned long *state) 364{ 365 struct gpio_fan_data *fan_data = cdev->devdata; 366 367 if (!fan_data) 368 return -EINVAL; 369 370 *state = fan_data->num_speed - 1; 371 return 0; 372} 373 374static int gpio_fan_get_cur_state(struct thermal_cooling_device *cdev, 375 unsigned long *state) 376{ 377 struct gpio_fan_data *fan_data = cdev->devdata; 378 379 if (!fan_data) 380 return -EINVAL; 381 382 *state = fan_data->speed_index; 383 return 0; 384} 385 386static int gpio_fan_set_cur_state(struct thermal_cooling_device *cdev, 387 unsigned long state) 388{ 389 struct gpio_fan_data *fan_data = cdev->devdata; 390 391 if (!fan_data) 392 return -EINVAL; 393 394 if (state >= fan_data->num_speed) 395 return -EINVAL; 396 397 set_fan_speed(fan_data, state); 398 return 0; 399} 400 401static const struct thermal_cooling_device_ops gpio_fan_cool_ops = { 402 .get_max_state = gpio_fan_get_max_state, 403 .get_cur_state = gpio_fan_get_cur_state, 404 .set_cur_state = gpio_fan_set_cur_state, 405}; 406 407/* 408 * Translate OpenFirmware node properties into platform_data 409 */ 410static int gpio_fan_get_of_data(struct gpio_fan_data *fan_data) 411{ 412 struct gpio_fan_speed *speed; 413 struct device *dev = fan_data->dev; 414 struct device_node *np = dev->of_node; 415 struct gpio_desc **gpios; 416 unsigned i; 417 u32 u; 418 struct property *prop; 419 const __be32 *p; 420 421 /* Alarm GPIO if one exists */ 422 fan_data->alarm_gpio = devm_gpiod_get_optional(dev, "alarm", GPIOD_IN); 423 if (IS_ERR(fan_data->alarm_gpio)) 424 return PTR_ERR(fan_data->alarm_gpio); 425 426 /* Fill GPIO pin array */ 427 fan_data->num_gpios = gpiod_count(dev, NULL); 428 if (fan_data->num_gpios <= 0) { 429 if (fan_data->alarm_gpio) 430 return 0; 431 dev_err(dev, "DT properties empty / missing"); 432 return -ENODEV; 433 } 434 gpios = devm_kcalloc(dev, 435 fan_data->num_gpios, sizeof(struct gpio_desc *), 436 GFP_KERNEL); 437 if (!gpios) 438 return -ENOMEM; 439 for (i = 0; i < fan_data->num_gpios; i++) { 440 gpios[i] = devm_gpiod_get_index(dev, NULL, i, GPIOD_ASIS); 441 if (IS_ERR(gpios[i])) 442 return PTR_ERR(gpios[i]); 443 } 444 fan_data->gpios = gpios; 445 446 /* Get number of RPM/ctrl_val pairs in speed map */ 447 prop = of_find_property(np, "gpio-fan,speed-map", &i); 448 if (!prop) { 449 dev_err(dev, "gpio-fan,speed-map DT property missing"); 450 return -ENODEV; 451 } 452 i = i / sizeof(u32); 453 if (i == 0 || i & 1) { 454 dev_err(dev, "gpio-fan,speed-map contains zero/odd number of entries"); 455 return -ENODEV; 456 } 457 fan_data->num_speed = i / 2; 458 459 /* 460 * Populate speed map 461 * Speed map is in the form <RPM ctrl_val RPM ctrl_val ...> 462 * this needs splitting into pairs to create gpio_fan_speed structs 463 */ 464 speed = devm_kcalloc(dev, 465 fan_data->num_speed, sizeof(struct gpio_fan_speed), 466 GFP_KERNEL); 467 if (!speed) 468 return -ENOMEM; 469 p = NULL; 470 for (i = 0; i < fan_data->num_speed; i++) { 471 p = of_prop_next_u32(prop, p, &u); 472 if (!p) 473 return -ENODEV; 474 speed[i].rpm = u; 475 p = of_prop_next_u32(prop, p, &u); 476 if (!p) 477 return -ENODEV; 478 speed[i].ctrl_val = u; 479 } 480 fan_data->speed = speed; 481 482 return 0; 483} 484 485static const struct of_device_id of_gpio_fan_match[] = { 486 { .compatible = "gpio-fan", }, 487 {}, 488}; 489MODULE_DEVICE_TABLE(of, of_gpio_fan_match); 490 491static void gpio_fan_stop(void *data) 492{ 493 set_fan_speed(data, 0); 494} 495 496static int gpio_fan_probe(struct platform_device *pdev) 497{ 498 int err; 499 struct gpio_fan_data *fan_data; 500 struct device *dev = &pdev->dev; 501 struct device_node *np = dev->of_node; 502 503 fan_data = devm_kzalloc(dev, sizeof(struct gpio_fan_data), 504 GFP_KERNEL); 505 if (!fan_data) 506 return -ENOMEM; 507 508 fan_data->dev = dev; 509 err = gpio_fan_get_of_data(fan_data); 510 if (err) 511 return err; 512 513 platform_set_drvdata(pdev, fan_data); 514 mutex_init(&fan_data->lock); 515 516 /* Configure control GPIOs if available. */ 517 if (fan_data->gpios && fan_data->num_gpios > 0) { 518 if (!fan_data->speed || fan_data->num_speed <= 1) 519 return -EINVAL; 520 err = fan_ctrl_init(fan_data); 521 if (err) 522 return err; 523 err = devm_add_action_or_reset(dev, gpio_fan_stop, fan_data); 524 if (err) 525 return err; 526 } 527 528 /* Make this driver part of hwmon class. */ 529 fan_data->hwmon_dev = 530 devm_hwmon_device_register_with_groups(dev, 531 "gpio_fan", fan_data, 532 gpio_fan_groups); 533 if (IS_ERR(fan_data->hwmon_dev)) 534 return PTR_ERR(fan_data->hwmon_dev); 535 536 /* Configure alarm GPIO if available. */ 537 if (fan_data->alarm_gpio) { 538 err = fan_alarm_init(fan_data); 539 if (err) 540 return err; 541 } 542 543 /* Optional cooling device register for Device tree platforms */ 544 fan_data->cdev = devm_thermal_of_cooling_device_register(dev, np, 545 "gpio-fan", fan_data, &gpio_fan_cool_ops); 546 547 dev_info(dev, "GPIO fan initialized\n"); 548 549 return 0; 550} 551 552static void gpio_fan_shutdown(struct platform_device *pdev) 553{ 554 struct gpio_fan_data *fan_data = platform_get_drvdata(pdev); 555 556 if (fan_data->gpios) 557 set_fan_speed(fan_data, 0); 558} 559 560#ifdef CONFIG_PM_SLEEP 561static int gpio_fan_suspend(struct device *dev) 562{ 563 struct gpio_fan_data *fan_data = dev_get_drvdata(dev); 564 565 if (fan_data->gpios) { 566 fan_data->resume_speed = fan_data->speed_index; 567 set_fan_speed(fan_data, 0); 568 } 569 570 return 0; 571} 572 573static int gpio_fan_resume(struct device *dev) 574{ 575 struct gpio_fan_data *fan_data = dev_get_drvdata(dev); 576 577 if (fan_data->gpios) 578 set_fan_speed(fan_data, fan_data->resume_speed); 579 580 return 0; 581} 582 583static SIMPLE_DEV_PM_OPS(gpio_fan_pm, gpio_fan_suspend, gpio_fan_resume); 584#define GPIO_FAN_PM (&gpio_fan_pm) 585#else 586#define GPIO_FAN_PM NULL 587#endif 588 589static struct platform_driver gpio_fan_driver = { 590 .probe = gpio_fan_probe, 591 .shutdown = gpio_fan_shutdown, 592 .driver = { 593 .name = "gpio-fan", 594 .pm = GPIO_FAN_PM, 595 .of_match_table = of_match_ptr(of_gpio_fan_match), 596 }, 597}; 598 599module_platform_driver(gpio_fan_driver); 600 601MODULE_AUTHOR("Simon Guinot <sguinot@lacie.com>"); 602MODULE_DESCRIPTION("GPIO FAN driver"); 603MODULE_LICENSE("GPL"); 604MODULE_ALIAS("platform:gpio-fan"); 605