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.h> 35 #include <linux/of_platform.h> 36 #include <linux/of_gpio.h> 37 38 struct gpio_fan_data { 39 struct platform_device *pdev; 40 struct device *hwmon_dev; 41 struct mutex lock; /* lock GPIOs operations. */ 42 int num_ctrl; 43 unsigned *ctrl; 44 int num_speed; 45 struct gpio_fan_speed *speed; 46 int speed_index; 47 #ifdef CONFIG_PM_SLEEP 48 int resume_speed; 49 #endif 50 bool pwm_enable; 51 struct gpio_fan_alarm *alarm; 52 struct work_struct alarm_work; 53 }; 54 55 /* 56 * Alarm GPIO. 57 */ 58 59 static void fan_alarm_notify(struct work_struct *ws) 60 { 61 struct gpio_fan_data *fan_data = 62 container_of(ws, struct gpio_fan_data, alarm_work); 63 64 sysfs_notify(&fan_data->pdev->dev.kobj, NULL, "fan1_alarm"); 65 kobject_uevent(&fan_data->pdev->dev.kobj, KOBJ_CHANGE); 66 } 67 68 static irqreturn_t fan_alarm_irq_handler(int irq, void *dev_id) 69 { 70 struct gpio_fan_data *fan_data = dev_id; 71 72 schedule_work(&fan_data->alarm_work); 73 74 return IRQ_NONE; 75 } 76 77 static ssize_t show_fan_alarm(struct device *dev, 78 struct device_attribute *attr, char *buf) 79 { 80 struct gpio_fan_data *fan_data = dev_get_drvdata(dev); 81 struct gpio_fan_alarm *alarm = fan_data->alarm; 82 int value = gpio_get_value_cansleep(alarm->gpio); 83 84 if (alarm->active_low) 85 value = !value; 86 87 return sprintf(buf, "%d\n", value); 88 } 89 90 static DEVICE_ATTR(fan1_alarm, S_IRUGO, show_fan_alarm, NULL); 91 92 static int fan_alarm_init(struct gpio_fan_data *fan_data, 93 struct gpio_fan_alarm *alarm) 94 { 95 int err; 96 int alarm_irq; 97 struct platform_device *pdev = fan_data->pdev; 98 99 fan_data->alarm = alarm; 100 101 err = devm_gpio_request(&pdev->dev, alarm->gpio, "GPIO fan alarm"); 102 if (err) 103 return err; 104 105 err = gpio_direction_input(alarm->gpio); 106 if (err) 107 return err; 108 109 /* 110 * If the alarm GPIO don't support interrupts, just leave 111 * without initializing the fail notification support. 112 */ 113 alarm_irq = gpio_to_irq(alarm->gpio); 114 if (alarm_irq < 0) 115 return 0; 116 117 INIT_WORK(&fan_data->alarm_work, fan_alarm_notify); 118 irq_set_irq_type(alarm_irq, IRQ_TYPE_EDGE_BOTH); 119 err = devm_request_irq(&pdev->dev, alarm_irq, fan_alarm_irq_handler, 120 IRQF_SHARED, "GPIO fan alarm", fan_data); 121 return err; 122 } 123 124 /* 125 * Control GPIOs. 126 */ 127 128 /* Must be called with fan_data->lock held, except during initialization. */ 129 static void __set_fan_ctrl(struct gpio_fan_data *fan_data, int ctrl_val) 130 { 131 int i; 132 133 for (i = 0; i < fan_data->num_ctrl; i++) 134 gpio_set_value_cansleep(fan_data->ctrl[i], (ctrl_val >> i) & 1); 135 } 136 137 static int __get_fan_ctrl(struct gpio_fan_data *fan_data) 138 { 139 int i; 140 int ctrl_val = 0; 141 142 for (i = 0; i < fan_data->num_ctrl; i++) { 143 int value; 144 145 value = gpio_get_value_cansleep(fan_data->ctrl[i]); 146 ctrl_val |= (value << i); 147 } 148 return ctrl_val; 149 } 150 151 /* Must be called with fan_data->lock held, except during initialization. */ 152 static void set_fan_speed(struct gpio_fan_data *fan_data, int speed_index) 153 { 154 if (fan_data->speed_index == speed_index) 155 return; 156 157 __set_fan_ctrl(fan_data, fan_data->speed[speed_index].ctrl_val); 158 fan_data->speed_index = speed_index; 159 } 160 161 static int get_fan_speed_index(struct gpio_fan_data *fan_data) 162 { 163 int ctrl_val = __get_fan_ctrl(fan_data); 164 int i; 165 166 for (i = 0; i < fan_data->num_speed; i++) 167 if (fan_data->speed[i].ctrl_val == ctrl_val) 168 return i; 169 170 dev_warn(&fan_data->pdev->dev, 171 "missing speed array entry for GPIO value 0x%x\n", ctrl_val); 172 173 return -ENODEV; 174 } 175 176 static int rpm_to_speed_index(struct gpio_fan_data *fan_data, unsigned long rpm) 177 { 178 struct gpio_fan_speed *speed = fan_data->speed; 179 int i; 180 181 for (i = 0; i < fan_data->num_speed; i++) 182 if (speed[i].rpm >= rpm) 183 return i; 184 185 return fan_data->num_speed - 1; 186 } 187 188 static ssize_t show_pwm(struct device *dev, 189 struct device_attribute *attr, char *buf) 190 { 191 struct gpio_fan_data *fan_data = dev_get_drvdata(dev); 192 u8 pwm = fan_data->speed_index * 255 / (fan_data->num_speed - 1); 193 194 return sprintf(buf, "%d\n", pwm); 195 } 196 197 static ssize_t set_pwm(struct device *dev, struct device_attribute *attr, 198 const char *buf, size_t count) 199 { 200 struct gpio_fan_data *fan_data = dev_get_drvdata(dev); 201 unsigned long pwm; 202 int speed_index; 203 int ret = count; 204 205 if (kstrtoul(buf, 10, &pwm) || pwm > 255) 206 return -EINVAL; 207 208 mutex_lock(&fan_data->lock); 209 210 if (!fan_data->pwm_enable) { 211 ret = -EPERM; 212 goto exit_unlock; 213 } 214 215 speed_index = DIV_ROUND_UP(pwm * (fan_data->num_speed - 1), 255); 216 set_fan_speed(fan_data, speed_index); 217 218 exit_unlock: 219 mutex_unlock(&fan_data->lock); 220 221 return ret; 222 } 223 224 static ssize_t show_pwm_enable(struct device *dev, 225 struct device_attribute *attr, char *buf) 226 { 227 struct gpio_fan_data *fan_data = dev_get_drvdata(dev); 228 229 return sprintf(buf, "%d\n", fan_data->pwm_enable); 230 } 231 232 static ssize_t set_pwm_enable(struct device *dev, struct device_attribute *attr, 233 const char *buf, size_t count) 234 { 235 struct gpio_fan_data *fan_data = dev_get_drvdata(dev); 236 unsigned long val; 237 238 if (kstrtoul(buf, 10, &val) || val > 1) 239 return -EINVAL; 240 241 if (fan_data->pwm_enable == val) 242 return count; 243 244 mutex_lock(&fan_data->lock); 245 246 fan_data->pwm_enable = val; 247 248 /* Disable manual control mode: set fan at full speed. */ 249 if (val == 0) 250 set_fan_speed(fan_data, fan_data->num_speed - 1); 251 252 mutex_unlock(&fan_data->lock); 253 254 return count; 255 } 256 257 static ssize_t show_pwm_mode(struct device *dev, 258 struct device_attribute *attr, char *buf) 259 { 260 return sprintf(buf, "0\n"); 261 } 262 263 static ssize_t show_rpm_min(struct device *dev, 264 struct device_attribute *attr, char *buf) 265 { 266 struct gpio_fan_data *fan_data = dev_get_drvdata(dev); 267 268 return sprintf(buf, "%d\n", fan_data->speed[0].rpm); 269 } 270 271 static ssize_t show_rpm_max(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", 277 fan_data->speed[fan_data->num_speed - 1].rpm); 278 } 279 280 static ssize_t show_rpm(struct device *dev, 281 struct device_attribute *attr, char *buf) 282 { 283 struct gpio_fan_data *fan_data = dev_get_drvdata(dev); 284 285 return sprintf(buf, "%d\n", fan_data->speed[fan_data->speed_index].rpm); 286 } 287 288 static ssize_t set_rpm(struct device *dev, struct device_attribute *attr, 289 const char *buf, size_t count) 290 { 291 struct gpio_fan_data *fan_data = dev_get_drvdata(dev); 292 unsigned long rpm; 293 int ret = count; 294 295 if (kstrtoul(buf, 10, &rpm)) 296 return -EINVAL; 297 298 mutex_lock(&fan_data->lock); 299 300 if (!fan_data->pwm_enable) { 301 ret = -EPERM; 302 goto exit_unlock; 303 } 304 305 set_fan_speed(fan_data, rpm_to_speed_index(fan_data, rpm)); 306 307 exit_unlock: 308 mutex_unlock(&fan_data->lock); 309 310 return ret; 311 } 312 313 static DEVICE_ATTR(pwm1, S_IRUGO | S_IWUSR, show_pwm, set_pwm); 314 static DEVICE_ATTR(pwm1_enable, S_IRUGO | S_IWUSR, 315 show_pwm_enable, set_pwm_enable); 316 static DEVICE_ATTR(pwm1_mode, S_IRUGO, show_pwm_mode, NULL); 317 static DEVICE_ATTR(fan1_min, S_IRUGO, show_rpm_min, NULL); 318 static DEVICE_ATTR(fan1_max, S_IRUGO, show_rpm_max, NULL); 319 static DEVICE_ATTR(fan1_input, S_IRUGO, show_rpm, NULL); 320 static DEVICE_ATTR(fan1_target, S_IRUGO | S_IWUSR, show_rpm, set_rpm); 321 322 static umode_t gpio_fan_is_visible(struct kobject *kobj, 323 struct attribute *attr, int index) 324 { 325 struct device *dev = container_of(kobj, struct device, kobj); 326 struct gpio_fan_data *data = dev_get_drvdata(dev); 327 328 if (index == 0 && !data->alarm) 329 return 0; 330 if (index > 0 && !data->ctrl) 331 return 0; 332 333 return attr->mode; 334 } 335 336 static struct attribute *gpio_fan_attributes[] = { 337 &dev_attr_fan1_alarm.attr, /* 0 */ 338 &dev_attr_pwm1.attr, /* 1 */ 339 &dev_attr_pwm1_enable.attr, 340 &dev_attr_pwm1_mode.attr, 341 &dev_attr_fan1_input.attr, 342 &dev_attr_fan1_target.attr, 343 &dev_attr_fan1_min.attr, 344 &dev_attr_fan1_max.attr, 345 NULL 346 }; 347 348 static const struct attribute_group gpio_fan_group = { 349 .attrs = gpio_fan_attributes, 350 .is_visible = gpio_fan_is_visible, 351 }; 352 353 static const struct attribute_group *gpio_fan_groups[] = { 354 &gpio_fan_group, 355 NULL 356 }; 357 358 static int fan_ctrl_init(struct gpio_fan_data *fan_data, 359 struct gpio_fan_platform_data *pdata) 360 { 361 struct platform_device *pdev = fan_data->pdev; 362 int num_ctrl = pdata->num_ctrl; 363 unsigned *ctrl = pdata->ctrl; 364 int i, err; 365 366 for (i = 0; i < num_ctrl; i++) { 367 err = devm_gpio_request(&pdev->dev, ctrl[i], 368 "GPIO fan control"); 369 if (err) 370 return err; 371 372 err = gpio_direction_output(ctrl[i], 373 gpio_get_value_cansleep(ctrl[i])); 374 if (err) 375 return err; 376 } 377 378 fan_data->num_ctrl = num_ctrl; 379 fan_data->ctrl = ctrl; 380 fan_data->num_speed = pdata->num_speed; 381 fan_data->speed = pdata->speed; 382 fan_data->pwm_enable = true; /* Enable manual fan speed control. */ 383 fan_data->speed_index = get_fan_speed_index(fan_data); 384 if (fan_data->speed_index < 0) 385 return fan_data->speed_index; 386 387 return 0; 388 } 389 390 #ifdef CONFIG_OF_GPIO 391 /* 392 * Translate OpenFirmware node properties into platform_data 393 */ 394 static int gpio_fan_get_of_pdata(struct device *dev, 395 struct gpio_fan_platform_data *pdata) 396 { 397 struct device_node *node; 398 struct gpio_fan_speed *speed; 399 unsigned *ctrl; 400 unsigned i; 401 u32 u; 402 struct property *prop; 403 const __be32 *p; 404 405 node = dev->of_node; 406 407 /* Fill GPIO pin array */ 408 pdata->num_ctrl = of_gpio_count(node); 409 if (pdata->num_ctrl <= 0) { 410 dev_err(dev, "gpios DT property empty / missing"); 411 return -ENODEV; 412 } 413 ctrl = devm_kzalloc(dev, pdata->num_ctrl * sizeof(unsigned), 414 GFP_KERNEL); 415 if (!ctrl) 416 return -ENOMEM; 417 for (i = 0; i < pdata->num_ctrl; i++) { 418 int val; 419 420 val = of_get_gpio(node, i); 421 if (val < 0) 422 return val; 423 ctrl[i] = val; 424 } 425 pdata->ctrl = ctrl; 426 427 /* Get number of RPM/ctrl_val pairs in speed map */ 428 prop = of_find_property(node, "gpio-fan,speed-map", &i); 429 if (!prop) { 430 dev_err(dev, "gpio-fan,speed-map DT property missing"); 431 return -ENODEV; 432 } 433 i = i / sizeof(u32); 434 if (i == 0 || i & 1) { 435 dev_err(dev, "gpio-fan,speed-map contains zero/odd number of entries"); 436 return -ENODEV; 437 } 438 pdata->num_speed = i / 2; 439 440 /* 441 * Populate speed map 442 * Speed map is in the form <RPM ctrl_val RPM ctrl_val ...> 443 * this needs splitting into pairs to create gpio_fan_speed structs 444 */ 445 speed = devm_kzalloc(dev, 446 pdata->num_speed * sizeof(struct gpio_fan_speed), 447 GFP_KERNEL); 448 if (!speed) 449 return -ENOMEM; 450 p = NULL; 451 for (i = 0; i < pdata->num_speed; i++) { 452 p = of_prop_next_u32(prop, p, &u); 453 if (!p) 454 return -ENODEV; 455 speed[i].rpm = u; 456 p = of_prop_next_u32(prop, p, &u); 457 if (!p) 458 return -ENODEV; 459 speed[i].ctrl_val = u; 460 } 461 pdata->speed = speed; 462 463 /* Alarm GPIO if one exists */ 464 if (of_gpio_named_count(node, "alarm-gpios") > 0) { 465 struct gpio_fan_alarm *alarm; 466 int val; 467 enum of_gpio_flags flags; 468 469 alarm = devm_kzalloc(dev, sizeof(struct gpio_fan_alarm), 470 GFP_KERNEL); 471 if (!alarm) 472 return -ENOMEM; 473 474 val = of_get_named_gpio_flags(node, "alarm-gpios", 0, &flags); 475 if (val < 0) 476 return val; 477 alarm->gpio = val; 478 alarm->active_low = flags & OF_GPIO_ACTIVE_LOW; 479 480 pdata->alarm = alarm; 481 } 482 483 return 0; 484 } 485 486 static const struct of_device_id of_gpio_fan_match[] = { 487 { .compatible = "gpio-fan", }, 488 {}, 489 }; 490 #endif /* CONFIG_OF_GPIO */ 491 492 static int gpio_fan_probe(struct platform_device *pdev) 493 { 494 int err; 495 struct gpio_fan_data *fan_data; 496 struct gpio_fan_platform_data *pdata = dev_get_platdata(&pdev->dev); 497 498 #ifdef CONFIG_OF_GPIO 499 if (!pdata) { 500 pdata = devm_kzalloc(&pdev->dev, 501 sizeof(struct gpio_fan_platform_data), 502 GFP_KERNEL); 503 if (!pdata) 504 return -ENOMEM; 505 506 err = gpio_fan_get_of_pdata(&pdev->dev, pdata); 507 if (err) 508 return err; 509 } 510 #else /* CONFIG_OF_GPIO */ 511 if (!pdata) 512 return -EINVAL; 513 #endif /* CONFIG_OF_GPIO */ 514 515 fan_data = devm_kzalloc(&pdev->dev, sizeof(struct gpio_fan_data), 516 GFP_KERNEL); 517 if (!fan_data) 518 return -ENOMEM; 519 520 fan_data->pdev = pdev; 521 platform_set_drvdata(pdev, fan_data); 522 mutex_init(&fan_data->lock); 523 524 /* Configure alarm GPIO if available. */ 525 if (pdata->alarm) { 526 err = fan_alarm_init(fan_data, pdata->alarm); 527 if (err) 528 return err; 529 } 530 531 /* Configure control GPIOs if available. */ 532 if (pdata->ctrl && pdata->num_ctrl > 0) { 533 if (!pdata->speed || pdata->num_speed <= 1) 534 return -EINVAL; 535 err = fan_ctrl_init(fan_data, pdata); 536 if (err) 537 return err; 538 } 539 540 /* Make this driver part of hwmon class. */ 541 fan_data->hwmon_dev = 542 devm_hwmon_device_register_with_groups(&pdev->dev, 543 "gpio_fan", fan_data, 544 gpio_fan_groups); 545 if (IS_ERR(fan_data->hwmon_dev)) 546 return PTR_ERR(fan_data->hwmon_dev); 547 548 dev_info(&pdev->dev, "GPIO fan initialized\n"); 549 550 return 0; 551 } 552 553 static void gpio_fan_shutdown(struct platform_device *pdev) 554 { 555 struct gpio_fan_data *fan_data = dev_get_drvdata(&pdev->dev); 556 557 if (fan_data->ctrl) 558 set_fan_speed(fan_data, 0); 559 } 560 561 #ifdef CONFIG_PM_SLEEP 562 static int gpio_fan_suspend(struct device *dev) 563 { 564 struct gpio_fan_data *fan_data = dev_get_drvdata(dev); 565 566 if (fan_data->ctrl) { 567 fan_data->resume_speed = fan_data->speed_index; 568 set_fan_speed(fan_data, 0); 569 } 570 571 return 0; 572 } 573 574 static int gpio_fan_resume(struct device *dev) 575 { 576 struct gpio_fan_data *fan_data = dev_get_drvdata(dev); 577 578 if (fan_data->ctrl) 579 set_fan_speed(fan_data, fan_data->resume_speed); 580 581 return 0; 582 } 583 584 static SIMPLE_DEV_PM_OPS(gpio_fan_pm, gpio_fan_suspend, gpio_fan_resume); 585 #define GPIO_FAN_PM (&gpio_fan_pm) 586 #else 587 #define GPIO_FAN_PM NULL 588 #endif 589 590 static struct platform_driver gpio_fan_driver = { 591 .probe = gpio_fan_probe, 592 .shutdown = gpio_fan_shutdown, 593 .driver = { 594 .name = "gpio-fan", 595 .pm = GPIO_FAN_PM, 596 #ifdef CONFIG_OF_GPIO 597 .of_match_table = of_match_ptr(of_gpio_fan_match), 598 #endif 599 }, 600 }; 601 602 module_platform_driver(gpio_fan_driver); 603 604 MODULE_AUTHOR("Simon Guinot <sguinot@lacie.com>"); 605 MODULE_DESCRIPTION("GPIO FAN driver"); 606 MODULE_LICENSE("GPL"); 607 MODULE_ALIAS("platform:gpio-fan"); 608