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