gpiolib.c revision 1c8732bb0355b929b09173464cdca7df4d516f89
1#include <linux/kernel.h> 2#include <linux/module.h> 3#include <linux/interrupt.h> 4#include <linux/irq.h> 5#include <linux/spinlock.h> 6#include <linux/list.h> 7#include <linux/device.h> 8#include <linux/err.h> 9#include <linux/debugfs.h> 10#include <linux/seq_file.h> 11#include <linux/gpio.h> 12#include <linux/of_gpio.h> 13#include <linux/idr.h> 14#include <linux/slab.h> 15#include <linux/acpi.h> 16#include <linux/gpio/driver.h> 17 18#include "gpiolib.h" 19 20#define CREATE_TRACE_POINTS 21#include <trace/events/gpio.h> 22 23/* Implementation infrastructure for GPIO interfaces. 24 * 25 * The GPIO programming interface allows for inlining speed-critical 26 * get/set operations for common cases, so that access to SOC-integrated 27 * GPIOs can sometimes cost only an instruction or two per bit. 28 */ 29 30 31/* When debugging, extend minimal trust to callers and platform code. 32 * Also emit diagnostic messages that may help initial bringup, when 33 * board setup or driver bugs are most common. 34 * 35 * Otherwise, minimize overhead in what may be bitbanging codepaths. 36 */ 37#ifdef DEBUG 38#define extra_checks 1 39#else 40#define extra_checks 0 41#endif 42 43/* gpio_lock prevents conflicts during gpio_desc[] table updates. 44 * While any GPIO is requested, its gpio_chip is not removable; 45 * each GPIO's "requested" flag serves as a lock and refcount. 46 */ 47static DEFINE_SPINLOCK(gpio_lock); 48 49struct gpio_desc { 50 struct gpio_chip *chip; 51 unsigned long flags; 52/* flag symbols are bit numbers */ 53#define FLAG_REQUESTED 0 54#define FLAG_IS_OUT 1 55#define FLAG_EXPORT 2 /* protected by sysfs_lock */ 56#define FLAG_SYSFS 3 /* exported via /sys/class/gpio/control */ 57#define FLAG_TRIG_FALL 4 /* trigger on falling edge */ 58#define FLAG_TRIG_RISE 5 /* trigger on rising edge */ 59#define FLAG_ACTIVE_LOW 6 /* value has active low */ 60#define FLAG_OPEN_DRAIN 7 /* Gpio is open drain type */ 61#define FLAG_OPEN_SOURCE 8 /* Gpio is open source type */ 62#define FLAG_USED_AS_IRQ 9 /* GPIO is connected to an IRQ */ 63 64#define ID_SHIFT 16 /* add new flags before this one */ 65 66#define GPIO_FLAGS_MASK ((1 << ID_SHIFT) - 1) 67#define GPIO_TRIGGER_MASK (BIT(FLAG_TRIG_FALL) | BIT(FLAG_TRIG_RISE)) 68 69#ifdef CONFIG_DEBUG_FS 70 const char *label; 71#endif 72}; 73static struct gpio_desc gpio_desc[ARCH_NR_GPIOS]; 74 75#define GPIO_OFFSET_VALID(chip, offset) (offset >= 0 && offset < chip->ngpio) 76 77static DEFINE_MUTEX(gpio_lookup_lock); 78static LIST_HEAD(gpio_lookup_list); 79static LIST_HEAD(gpio_chips); 80 81#ifdef CONFIG_GPIO_SYSFS 82static DEFINE_IDR(dirent_idr); 83#endif 84 85static int gpiod_request(struct gpio_desc *desc, const char *label); 86static void gpiod_free(struct gpio_desc *desc); 87 88/* With descriptor prefix */ 89 90#ifdef CONFIG_DEBUG_FS 91#define gpiod_emerg(desc, fmt, ...) \ 92 pr_emerg("gpio-%d (%s): " fmt, desc_to_gpio(desc), desc->label ? : "?",\ 93 ##__VA_ARGS__) 94#define gpiod_crit(desc, fmt, ...) \ 95 pr_crit("gpio-%d (%s): " fmt, desc_to_gpio(desc), desc->label ? : "?", \ 96 ##__VA_ARGS__) 97#define gpiod_err(desc, fmt, ...) \ 98 pr_err("gpio-%d (%s): " fmt, desc_to_gpio(desc), desc->label ? : "?", \ 99 ##__VA_ARGS__) 100#define gpiod_warn(desc, fmt, ...) \ 101 pr_warn("gpio-%d (%s): " fmt, desc_to_gpio(desc), desc->label ? : "?", \ 102 ##__VA_ARGS__) 103#define gpiod_info(desc, fmt, ...) \ 104 pr_info("gpio-%d (%s): " fmt, desc_to_gpio(desc), desc->label ? : "?", \ 105 ##__VA_ARGS__) 106#define gpiod_dbg(desc, fmt, ...) \ 107 pr_debug("gpio-%d (%s): " fmt, desc_to_gpio(desc), desc->label ? : "?",\ 108 ##__VA_ARGS__) 109#else 110#define gpiod_emerg(desc, fmt, ...) \ 111 pr_emerg("gpio-%d: " fmt, desc_to_gpio(desc), ##__VA_ARGS__) 112#define gpiod_crit(desc, fmt, ...) \ 113 pr_crit("gpio-%d: " fmt, desc_to_gpio(desc), ##__VA_ARGS__) 114#define gpiod_err(desc, fmt, ...) \ 115 pr_err("gpio-%d: " fmt, desc_to_gpio(desc), ##__VA_ARGS__) 116#define gpiod_warn(desc, fmt, ...) \ 117 pr_warn("gpio-%d: " fmt, desc_to_gpio(desc), ##__VA_ARGS__) 118#define gpiod_info(desc, fmt, ...) \ 119 pr_info("gpio-%d: " fmt, desc_to_gpio(desc), ##__VA_ARGS__) 120#define gpiod_dbg(desc, fmt, ...) \ 121 pr_debug("gpio-%d: " fmt, desc_to_gpio(desc), ##__VA_ARGS__) 122#endif 123 124/* With chip prefix */ 125 126#define chip_emerg(chip, fmt, ...) \ 127 pr_emerg("GPIO chip %s: " fmt, chip->label, ##__VA_ARGS__) 128#define chip_crit(chip, fmt, ...) \ 129 pr_crit("GPIO chip %s: " fmt, chip->label, ##__VA_ARGS__) 130#define chip_err(chip, fmt, ...) \ 131 pr_err("GPIO chip %s: " fmt, chip->label, ##__VA_ARGS__) 132#define chip_warn(chip, fmt, ...) \ 133 pr_warn("GPIO chip %s: " fmt, chip->label, ##__VA_ARGS__) 134#define chip_info(chip, fmt, ...) \ 135 pr_info("GPIO chip %s: " fmt, chip->label, ##__VA_ARGS__) 136#define chip_dbg(chip, fmt, ...) \ 137 pr_debug("GPIO chip %s: " fmt, chip->label, ##__VA_ARGS__) 138 139static inline void desc_set_label(struct gpio_desc *d, const char *label) 140{ 141#ifdef CONFIG_DEBUG_FS 142 d->label = label; 143#endif 144} 145 146/* 147 * Return the GPIO number of the passed descriptor relative to its chip 148 */ 149static int gpio_chip_hwgpio(const struct gpio_desc *desc) 150{ 151 return desc - &desc->chip->desc[0]; 152} 153 154/** 155 * Convert a GPIO number to its descriptor 156 */ 157struct gpio_desc *gpio_to_desc(unsigned gpio) 158{ 159 if (WARN(!gpio_is_valid(gpio), "invalid GPIO %d\n", gpio)) 160 return NULL; 161 else 162 return &gpio_desc[gpio]; 163} 164EXPORT_SYMBOL_GPL(gpio_to_desc); 165 166/** 167 * Get the GPIO descriptor corresponding to the given hw number for this chip. 168 */ 169struct gpio_desc *gpiochip_get_desc(struct gpio_chip *chip, 170 u16 hwnum) 171{ 172 if (hwnum >= chip->ngpio) 173 return ERR_PTR(-EINVAL); 174 175 return &chip->desc[hwnum]; 176} 177EXPORT_SYMBOL_GPL(gpiochip_get_desc); 178 179/** 180 * Convert a GPIO descriptor to the integer namespace. 181 * This should disappear in the future but is needed since we still 182 * use GPIO numbers for error messages and sysfs nodes 183 */ 184int desc_to_gpio(const struct gpio_desc *desc) 185{ 186 return desc - &gpio_desc[0]; 187} 188EXPORT_SYMBOL_GPL(desc_to_gpio); 189 190 191/* Warn when drivers omit gpio_request() calls -- legal but ill-advised 192 * when setting direction, and otherwise illegal. Until board setup code 193 * and drivers use explicit requests everywhere (which won't happen when 194 * those calls have no teeth) we can't avoid autorequesting. This nag 195 * message should motivate switching to explicit requests... so should 196 * the weaker cleanup after faults, compared to gpio_request(). 197 * 198 * NOTE: the autorequest mechanism is going away; at this point it's 199 * only "legal" in the sense that (old) code using it won't break yet, 200 * but instead only triggers a WARN() stack dump. 201 */ 202static int gpio_ensure_requested(struct gpio_desc *desc) 203{ 204 const struct gpio_chip *chip = desc->chip; 205 const int gpio = desc_to_gpio(desc); 206 207 if (WARN(test_and_set_bit(FLAG_REQUESTED, &desc->flags) == 0, 208 "autorequest GPIO-%d\n", gpio)) { 209 if (!try_module_get(chip->owner)) { 210 gpiod_err(desc, "%s: module can't be gotten\n", 211 __func__); 212 clear_bit(FLAG_REQUESTED, &desc->flags); 213 /* lose */ 214 return -EIO; 215 } 216 desc_set_label(desc, "[auto]"); 217 /* caller must chip->request() w/o spinlock */ 218 if (chip->request) 219 return 1; 220 } 221 return 0; 222} 223 224/** 225 * gpiod_to_chip - Return the GPIO chip to which a GPIO descriptor belongs 226 * @desc: descriptor to return the chip of 227 */ 228struct gpio_chip *gpiod_to_chip(const struct gpio_desc *desc) 229{ 230 return desc ? desc->chip : NULL; 231} 232EXPORT_SYMBOL_GPL(gpiod_to_chip); 233 234/* dynamic allocation of GPIOs, e.g. on a hotplugged device */ 235static int gpiochip_find_base(int ngpio) 236{ 237 struct gpio_chip *chip; 238 int base = ARCH_NR_GPIOS - ngpio; 239 240 list_for_each_entry_reverse(chip, &gpio_chips, list) { 241 /* found a free space? */ 242 if (chip->base + chip->ngpio <= base) 243 break; 244 else 245 /* nope, check the space right before the chip */ 246 base = chip->base - ngpio; 247 } 248 249 if (gpio_is_valid(base)) { 250 pr_debug("%s: found new base at %d\n", __func__, base); 251 return base; 252 } else { 253 pr_err("%s: cannot find free range\n", __func__); 254 return -ENOSPC; 255 } 256} 257 258/** 259 * gpiod_get_direction - return the current direction of a GPIO 260 * @desc: GPIO to get the direction of 261 * 262 * Return GPIOF_DIR_IN or GPIOF_DIR_OUT, or an error code in case of error. 263 * 264 * This function may sleep if gpiod_cansleep() is true. 265 */ 266int gpiod_get_direction(const struct gpio_desc *desc) 267{ 268 struct gpio_chip *chip; 269 unsigned offset; 270 int status = -EINVAL; 271 272 chip = gpiod_to_chip(desc); 273 offset = gpio_chip_hwgpio(desc); 274 275 if (!chip->get_direction) 276 return status; 277 278 status = chip->get_direction(chip, offset); 279 if (status > 0) { 280 /* GPIOF_DIR_IN, or other positive */ 281 status = 1; 282 /* FLAG_IS_OUT is just a cache of the result of get_direction(), 283 * so it does not affect constness per se */ 284 clear_bit(FLAG_IS_OUT, &((struct gpio_desc *)desc)->flags); 285 } 286 if (status == 0) { 287 /* GPIOF_DIR_OUT */ 288 set_bit(FLAG_IS_OUT, &((struct gpio_desc *)desc)->flags); 289 } 290 return status; 291} 292EXPORT_SYMBOL_GPL(gpiod_get_direction); 293 294#ifdef CONFIG_GPIO_SYSFS 295 296/* lock protects against unexport_gpio() being called while 297 * sysfs files are active. 298 */ 299static DEFINE_MUTEX(sysfs_lock); 300 301/* 302 * /sys/class/gpio/gpioN... only for GPIOs that are exported 303 * /direction 304 * * MAY BE OMITTED if kernel won't allow direction changes 305 * * is read/write as "in" or "out" 306 * * may also be written as "high" or "low", initializing 307 * output value as specified ("out" implies "low") 308 * /value 309 * * always readable, subject to hardware behavior 310 * * may be writable, as zero/nonzero 311 * /edge 312 * * configures behavior of poll(2) on /value 313 * * available only if pin can generate IRQs on input 314 * * is read/write as "none", "falling", "rising", or "both" 315 * /active_low 316 * * configures polarity of /value 317 * * is read/write as zero/nonzero 318 * * also affects existing and subsequent "falling" and "rising" 319 * /edge configuration 320 */ 321 322static ssize_t gpio_direction_show(struct device *dev, 323 struct device_attribute *attr, char *buf) 324{ 325 const struct gpio_desc *desc = dev_get_drvdata(dev); 326 ssize_t status; 327 328 mutex_lock(&sysfs_lock); 329 330 if (!test_bit(FLAG_EXPORT, &desc->flags)) { 331 status = -EIO; 332 } else { 333 gpiod_get_direction(desc); 334 status = sprintf(buf, "%s\n", 335 test_bit(FLAG_IS_OUT, &desc->flags) 336 ? "out" : "in"); 337 } 338 339 mutex_unlock(&sysfs_lock); 340 return status; 341} 342 343static ssize_t gpio_direction_store(struct device *dev, 344 struct device_attribute *attr, const char *buf, size_t size) 345{ 346 struct gpio_desc *desc = dev_get_drvdata(dev); 347 ssize_t status; 348 349 mutex_lock(&sysfs_lock); 350 351 if (!test_bit(FLAG_EXPORT, &desc->flags)) 352 status = -EIO; 353 else if (sysfs_streq(buf, "high")) 354 status = gpiod_direction_output_raw(desc, 1); 355 else if (sysfs_streq(buf, "out") || sysfs_streq(buf, "low")) 356 status = gpiod_direction_output_raw(desc, 0); 357 else if (sysfs_streq(buf, "in")) 358 status = gpiod_direction_input(desc); 359 else 360 status = -EINVAL; 361 362 mutex_unlock(&sysfs_lock); 363 return status ? : size; 364} 365 366static /* const */ DEVICE_ATTR(direction, 0644, 367 gpio_direction_show, gpio_direction_store); 368 369static ssize_t gpio_value_show(struct device *dev, 370 struct device_attribute *attr, char *buf) 371{ 372 struct gpio_desc *desc = dev_get_drvdata(dev); 373 ssize_t status; 374 375 mutex_lock(&sysfs_lock); 376 377 if (!test_bit(FLAG_EXPORT, &desc->flags)) 378 status = -EIO; 379 else 380 status = sprintf(buf, "%d\n", gpiod_get_value_cansleep(desc)); 381 382 mutex_unlock(&sysfs_lock); 383 return status; 384} 385 386static ssize_t gpio_value_store(struct device *dev, 387 struct device_attribute *attr, const char *buf, size_t size) 388{ 389 struct gpio_desc *desc = dev_get_drvdata(dev); 390 ssize_t status; 391 392 mutex_lock(&sysfs_lock); 393 394 if (!test_bit(FLAG_EXPORT, &desc->flags)) 395 status = -EIO; 396 else if (!test_bit(FLAG_IS_OUT, &desc->flags)) 397 status = -EPERM; 398 else { 399 long value; 400 401 status = kstrtol(buf, 0, &value); 402 if (status == 0) { 403 gpiod_set_value_cansleep(desc, value); 404 status = size; 405 } 406 } 407 408 mutex_unlock(&sysfs_lock); 409 return status; 410} 411 412static const DEVICE_ATTR(value, 0644, 413 gpio_value_show, gpio_value_store); 414 415static irqreturn_t gpio_sysfs_irq(int irq, void *priv) 416{ 417 struct kernfs_node *value_sd = priv; 418 419 sysfs_notify_dirent(value_sd); 420 return IRQ_HANDLED; 421} 422 423static int gpio_setup_irq(struct gpio_desc *desc, struct device *dev, 424 unsigned long gpio_flags) 425{ 426 struct kernfs_node *value_sd; 427 unsigned long irq_flags; 428 int ret, irq, id; 429 430 if ((desc->flags & GPIO_TRIGGER_MASK) == gpio_flags) 431 return 0; 432 433 irq = gpiod_to_irq(desc); 434 if (irq < 0) 435 return -EIO; 436 437 id = desc->flags >> ID_SHIFT; 438 value_sd = idr_find(&dirent_idr, id); 439 if (value_sd) 440 free_irq(irq, value_sd); 441 442 desc->flags &= ~GPIO_TRIGGER_MASK; 443 444 if (!gpio_flags) { 445 gpiod_unlock_as_irq(desc); 446 ret = 0; 447 goto free_id; 448 } 449 450 irq_flags = IRQF_SHARED; 451 if (test_bit(FLAG_TRIG_FALL, &gpio_flags)) 452 irq_flags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ? 453 IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING; 454 if (test_bit(FLAG_TRIG_RISE, &gpio_flags)) 455 irq_flags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ? 456 IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING; 457 458 if (!value_sd) { 459 value_sd = sysfs_get_dirent(dev->kobj.sd, "value"); 460 if (!value_sd) { 461 ret = -ENODEV; 462 goto err_out; 463 } 464 465 ret = idr_alloc(&dirent_idr, value_sd, 1, 0, GFP_KERNEL); 466 if (ret < 0) 467 goto free_sd; 468 id = ret; 469 470 desc->flags &= GPIO_FLAGS_MASK; 471 desc->flags |= (unsigned long)id << ID_SHIFT; 472 473 if (desc->flags >> ID_SHIFT != id) { 474 ret = -ERANGE; 475 goto free_id; 476 } 477 } 478 479 ret = request_any_context_irq(irq, gpio_sysfs_irq, irq_flags, 480 "gpiolib", value_sd); 481 if (ret < 0) 482 goto free_id; 483 484 ret = gpiod_lock_as_irq(desc); 485 if (ret < 0) { 486 gpiod_warn(desc, "failed to flag the GPIO for IRQ\n"); 487 goto free_id; 488 } 489 490 desc->flags |= gpio_flags; 491 return 0; 492 493free_id: 494 idr_remove(&dirent_idr, id); 495 desc->flags &= GPIO_FLAGS_MASK; 496free_sd: 497 if (value_sd) 498 sysfs_put(value_sd); 499err_out: 500 return ret; 501} 502 503static const struct { 504 const char *name; 505 unsigned long flags; 506} trigger_types[] = { 507 { "none", 0 }, 508 { "falling", BIT(FLAG_TRIG_FALL) }, 509 { "rising", BIT(FLAG_TRIG_RISE) }, 510 { "both", BIT(FLAG_TRIG_FALL) | BIT(FLAG_TRIG_RISE) }, 511}; 512 513static ssize_t gpio_edge_show(struct device *dev, 514 struct device_attribute *attr, char *buf) 515{ 516 const struct gpio_desc *desc = dev_get_drvdata(dev); 517 ssize_t status; 518 519 mutex_lock(&sysfs_lock); 520 521 if (!test_bit(FLAG_EXPORT, &desc->flags)) 522 status = -EIO; 523 else { 524 int i; 525 526 status = 0; 527 for (i = 0; i < ARRAY_SIZE(trigger_types); i++) 528 if ((desc->flags & GPIO_TRIGGER_MASK) 529 == trigger_types[i].flags) { 530 status = sprintf(buf, "%s\n", 531 trigger_types[i].name); 532 break; 533 } 534 } 535 536 mutex_unlock(&sysfs_lock); 537 return status; 538} 539 540static ssize_t gpio_edge_store(struct device *dev, 541 struct device_attribute *attr, const char *buf, size_t size) 542{ 543 struct gpio_desc *desc = dev_get_drvdata(dev); 544 ssize_t status; 545 int i; 546 547 for (i = 0; i < ARRAY_SIZE(trigger_types); i++) 548 if (sysfs_streq(trigger_types[i].name, buf)) 549 goto found; 550 return -EINVAL; 551 552found: 553 mutex_lock(&sysfs_lock); 554 555 if (!test_bit(FLAG_EXPORT, &desc->flags)) 556 status = -EIO; 557 else { 558 status = gpio_setup_irq(desc, dev, trigger_types[i].flags); 559 if (!status) 560 status = size; 561 } 562 563 mutex_unlock(&sysfs_lock); 564 565 return status; 566} 567 568static DEVICE_ATTR(edge, 0644, gpio_edge_show, gpio_edge_store); 569 570static int sysfs_set_active_low(struct gpio_desc *desc, struct device *dev, 571 int value) 572{ 573 int status = 0; 574 575 if (!!test_bit(FLAG_ACTIVE_LOW, &desc->flags) == !!value) 576 return 0; 577 578 if (value) 579 set_bit(FLAG_ACTIVE_LOW, &desc->flags); 580 else 581 clear_bit(FLAG_ACTIVE_LOW, &desc->flags); 582 583 /* reconfigure poll(2) support if enabled on one edge only */ 584 if (dev != NULL && (!!test_bit(FLAG_TRIG_RISE, &desc->flags) ^ 585 !!test_bit(FLAG_TRIG_FALL, &desc->flags))) { 586 unsigned long trigger_flags = desc->flags & GPIO_TRIGGER_MASK; 587 588 gpio_setup_irq(desc, dev, 0); 589 status = gpio_setup_irq(desc, dev, trigger_flags); 590 } 591 592 return status; 593} 594 595static ssize_t gpio_active_low_show(struct device *dev, 596 struct device_attribute *attr, char *buf) 597{ 598 const struct gpio_desc *desc = dev_get_drvdata(dev); 599 ssize_t status; 600 601 mutex_lock(&sysfs_lock); 602 603 if (!test_bit(FLAG_EXPORT, &desc->flags)) 604 status = -EIO; 605 else 606 status = sprintf(buf, "%d\n", 607 !!test_bit(FLAG_ACTIVE_LOW, &desc->flags)); 608 609 mutex_unlock(&sysfs_lock); 610 611 return status; 612} 613 614static ssize_t gpio_active_low_store(struct device *dev, 615 struct device_attribute *attr, const char *buf, size_t size) 616{ 617 struct gpio_desc *desc = dev_get_drvdata(dev); 618 ssize_t status; 619 620 mutex_lock(&sysfs_lock); 621 622 if (!test_bit(FLAG_EXPORT, &desc->flags)) { 623 status = -EIO; 624 } else { 625 long value; 626 627 status = kstrtol(buf, 0, &value); 628 if (status == 0) 629 status = sysfs_set_active_low(desc, dev, value != 0); 630 } 631 632 mutex_unlock(&sysfs_lock); 633 634 return status ? : size; 635} 636 637static const DEVICE_ATTR(active_low, 0644, 638 gpio_active_low_show, gpio_active_low_store); 639 640static const struct attribute *gpio_attrs[] = { 641 &dev_attr_value.attr, 642 &dev_attr_active_low.attr, 643 NULL, 644}; 645 646static const struct attribute_group gpio_attr_group = { 647 .attrs = (struct attribute **) gpio_attrs, 648}; 649 650/* 651 * /sys/class/gpio/gpiochipN/ 652 * /base ... matching gpio_chip.base (N) 653 * /label ... matching gpio_chip.label 654 * /ngpio ... matching gpio_chip.ngpio 655 */ 656 657static ssize_t chip_base_show(struct device *dev, 658 struct device_attribute *attr, char *buf) 659{ 660 const struct gpio_chip *chip = dev_get_drvdata(dev); 661 662 return sprintf(buf, "%d\n", chip->base); 663} 664static DEVICE_ATTR(base, 0444, chip_base_show, NULL); 665 666static ssize_t chip_label_show(struct device *dev, 667 struct device_attribute *attr, char *buf) 668{ 669 const struct gpio_chip *chip = dev_get_drvdata(dev); 670 671 return sprintf(buf, "%s\n", chip->label ? : ""); 672} 673static DEVICE_ATTR(label, 0444, chip_label_show, NULL); 674 675static ssize_t chip_ngpio_show(struct device *dev, 676 struct device_attribute *attr, char *buf) 677{ 678 const struct gpio_chip *chip = dev_get_drvdata(dev); 679 680 return sprintf(buf, "%u\n", chip->ngpio); 681} 682static DEVICE_ATTR(ngpio, 0444, chip_ngpio_show, NULL); 683 684static const struct attribute *gpiochip_attrs[] = { 685 &dev_attr_base.attr, 686 &dev_attr_label.attr, 687 &dev_attr_ngpio.attr, 688 NULL, 689}; 690 691static const struct attribute_group gpiochip_attr_group = { 692 .attrs = (struct attribute **) gpiochip_attrs, 693}; 694 695/* 696 * /sys/class/gpio/export ... write-only 697 * integer N ... number of GPIO to export (full access) 698 * /sys/class/gpio/unexport ... write-only 699 * integer N ... number of GPIO to unexport 700 */ 701static ssize_t export_store(struct class *class, 702 struct class_attribute *attr, 703 const char *buf, size_t len) 704{ 705 long gpio; 706 struct gpio_desc *desc; 707 int status; 708 709 status = kstrtol(buf, 0, &gpio); 710 if (status < 0) 711 goto done; 712 713 desc = gpio_to_desc(gpio); 714 /* reject invalid GPIOs */ 715 if (!desc) { 716 pr_warn("%s: invalid GPIO %ld\n", __func__, gpio); 717 return -EINVAL; 718 } 719 720 /* No extra locking here; FLAG_SYSFS just signifies that the 721 * request and export were done by on behalf of userspace, so 722 * they may be undone on its behalf too. 723 */ 724 725 status = gpiod_request(desc, "sysfs"); 726 if (status < 0) { 727 if (status == -EPROBE_DEFER) 728 status = -ENODEV; 729 goto done; 730 } 731 status = gpiod_export(desc, true); 732 if (status < 0) 733 gpiod_free(desc); 734 else 735 set_bit(FLAG_SYSFS, &desc->flags); 736 737done: 738 if (status) 739 pr_debug("%s: status %d\n", __func__, status); 740 return status ? : len; 741} 742 743static ssize_t unexport_store(struct class *class, 744 struct class_attribute *attr, 745 const char *buf, size_t len) 746{ 747 long gpio; 748 struct gpio_desc *desc; 749 int status; 750 751 status = kstrtol(buf, 0, &gpio); 752 if (status < 0) 753 goto done; 754 755 desc = gpio_to_desc(gpio); 756 /* reject bogus commands (gpio_unexport ignores them) */ 757 if (!desc) { 758 pr_warn("%s: invalid GPIO %ld\n", __func__, gpio); 759 return -EINVAL; 760 } 761 762 status = -EINVAL; 763 764 /* No extra locking here; FLAG_SYSFS just signifies that the 765 * request and export were done by on behalf of userspace, so 766 * they may be undone on its behalf too. 767 */ 768 if (test_and_clear_bit(FLAG_SYSFS, &desc->flags)) { 769 status = 0; 770 gpiod_free(desc); 771 } 772done: 773 if (status) 774 pr_debug("%s: status %d\n", __func__, status); 775 return status ? : len; 776} 777 778static struct class_attribute gpio_class_attrs[] = { 779 __ATTR(export, 0200, NULL, export_store), 780 __ATTR(unexport, 0200, NULL, unexport_store), 781 __ATTR_NULL, 782}; 783 784static struct class gpio_class = { 785 .name = "gpio", 786 .owner = THIS_MODULE, 787 788 .class_attrs = gpio_class_attrs, 789}; 790 791 792/** 793 * gpiod_export - export a GPIO through sysfs 794 * @gpio: gpio to make available, already requested 795 * @direction_may_change: true if userspace may change gpio direction 796 * Context: arch_initcall or later 797 * 798 * When drivers want to make a GPIO accessible to userspace after they 799 * have requested it -- perhaps while debugging, or as part of their 800 * public interface -- they may use this routine. If the GPIO can 801 * change direction (some can't) and the caller allows it, userspace 802 * will see "direction" sysfs attribute which may be used to change 803 * the gpio's direction. A "value" attribute will always be provided. 804 * 805 * Returns zero on success, else an error. 806 */ 807int gpiod_export(struct gpio_desc *desc, bool direction_may_change) 808{ 809 unsigned long flags; 810 int status; 811 const char *ioname = NULL; 812 struct device *dev; 813 int offset; 814 815 /* can't export until sysfs is available ... */ 816 if (!gpio_class.p) { 817 pr_debug("%s: called too early!\n", __func__); 818 return -ENOENT; 819 } 820 821 if (!desc) { 822 pr_debug("%s: invalid gpio descriptor\n", __func__); 823 return -EINVAL; 824 } 825 826 mutex_lock(&sysfs_lock); 827 828 spin_lock_irqsave(&gpio_lock, flags); 829 if (!test_bit(FLAG_REQUESTED, &desc->flags) || 830 test_bit(FLAG_EXPORT, &desc->flags)) { 831 spin_unlock_irqrestore(&gpio_lock, flags); 832 gpiod_dbg(desc, "%s: unavailable (requested=%d, exported=%d)\n", 833 __func__, 834 test_bit(FLAG_REQUESTED, &desc->flags), 835 test_bit(FLAG_EXPORT, &desc->flags)); 836 status = -EPERM; 837 goto fail_unlock; 838 } 839 840 if (!desc->chip->direction_input || !desc->chip->direction_output) 841 direction_may_change = false; 842 spin_unlock_irqrestore(&gpio_lock, flags); 843 844 offset = gpio_chip_hwgpio(desc); 845 if (desc->chip->names && desc->chip->names[offset]) 846 ioname = desc->chip->names[offset]; 847 848 dev = device_create(&gpio_class, desc->chip->dev, MKDEV(0, 0), 849 desc, ioname ? ioname : "gpio%u", 850 desc_to_gpio(desc)); 851 if (IS_ERR(dev)) { 852 status = PTR_ERR(dev); 853 goto fail_unlock; 854 } 855 856 status = sysfs_create_group(&dev->kobj, &gpio_attr_group); 857 if (status) 858 goto fail_unregister_device; 859 860 if (direction_may_change) { 861 status = device_create_file(dev, &dev_attr_direction); 862 if (status) 863 goto fail_unregister_device; 864 } 865 866 if (gpiod_to_irq(desc) >= 0 && (direction_may_change || 867 !test_bit(FLAG_IS_OUT, &desc->flags))) { 868 status = device_create_file(dev, &dev_attr_edge); 869 if (status) 870 goto fail_unregister_device; 871 } 872 873 set_bit(FLAG_EXPORT, &desc->flags); 874 mutex_unlock(&sysfs_lock); 875 return 0; 876 877fail_unregister_device: 878 device_unregister(dev); 879fail_unlock: 880 mutex_unlock(&sysfs_lock); 881 gpiod_dbg(desc, "%s: status %d\n", __func__, status); 882 return status; 883} 884EXPORT_SYMBOL_GPL(gpiod_export); 885 886static int match_export(struct device *dev, const void *data) 887{ 888 return dev_get_drvdata(dev) == data; 889} 890 891/** 892 * gpiod_export_link - create a sysfs link to an exported GPIO node 893 * @dev: device under which to create symlink 894 * @name: name of the symlink 895 * @gpio: gpio to create symlink to, already exported 896 * 897 * Set up a symlink from /sys/.../dev/name to /sys/class/gpio/gpioN 898 * node. Caller is responsible for unlinking. 899 * 900 * Returns zero on success, else an error. 901 */ 902int gpiod_export_link(struct device *dev, const char *name, 903 struct gpio_desc *desc) 904{ 905 int status = -EINVAL; 906 907 if (!desc) { 908 pr_warn("%s: invalid GPIO\n", __func__); 909 return -EINVAL; 910 } 911 912 mutex_lock(&sysfs_lock); 913 914 if (test_bit(FLAG_EXPORT, &desc->flags)) { 915 struct device *tdev; 916 917 tdev = class_find_device(&gpio_class, NULL, desc, match_export); 918 if (tdev != NULL) { 919 status = sysfs_create_link(&dev->kobj, &tdev->kobj, 920 name); 921 } else { 922 status = -ENODEV; 923 } 924 } 925 926 mutex_unlock(&sysfs_lock); 927 928 if (status) 929 gpiod_dbg(desc, "%s: status %d\n", __func__, status); 930 931 return status; 932} 933EXPORT_SYMBOL_GPL(gpiod_export_link); 934 935/** 936 * gpiod_sysfs_set_active_low - set the polarity of gpio sysfs value 937 * @gpio: gpio to change 938 * @value: non-zero to use active low, i.e. inverted values 939 * 940 * Set the polarity of /sys/class/gpio/gpioN/value sysfs attribute. 941 * The GPIO does not have to be exported yet. If poll(2) support has 942 * been enabled for either rising or falling edge, it will be 943 * reconfigured to follow the new polarity. 944 * 945 * Returns zero on success, else an error. 946 */ 947int gpiod_sysfs_set_active_low(struct gpio_desc *desc, int value) 948{ 949 struct device *dev = NULL; 950 int status = -EINVAL; 951 952 if (!desc) { 953 pr_warn("%s: invalid GPIO\n", __func__); 954 return -EINVAL; 955 } 956 957 mutex_lock(&sysfs_lock); 958 959 if (test_bit(FLAG_EXPORT, &desc->flags)) { 960 dev = class_find_device(&gpio_class, NULL, desc, match_export); 961 if (dev == NULL) { 962 status = -ENODEV; 963 goto unlock; 964 } 965 } 966 967 status = sysfs_set_active_low(desc, dev, value); 968 969unlock: 970 mutex_unlock(&sysfs_lock); 971 972 if (status) 973 gpiod_dbg(desc, "%s: status %d\n", __func__, status); 974 975 return status; 976} 977EXPORT_SYMBOL_GPL(gpiod_sysfs_set_active_low); 978 979/** 980 * gpiod_unexport - reverse effect of gpio_export() 981 * @gpio: gpio to make unavailable 982 * 983 * This is implicit on gpio_free(). 984 */ 985void gpiod_unexport(struct gpio_desc *desc) 986{ 987 int status = 0; 988 struct device *dev = NULL; 989 990 if (!desc) { 991 pr_warn("%s: invalid GPIO\n", __func__); 992 return; 993 } 994 995 mutex_lock(&sysfs_lock); 996 997 if (test_bit(FLAG_EXPORT, &desc->flags)) { 998 999 dev = class_find_device(&gpio_class, NULL, desc, match_export); 1000 if (dev) { 1001 gpio_setup_irq(desc, dev, 0); 1002 clear_bit(FLAG_EXPORT, &desc->flags); 1003 } else 1004 status = -ENODEV; 1005 } 1006 1007 mutex_unlock(&sysfs_lock); 1008 1009 if (dev) { 1010 device_unregister(dev); 1011 put_device(dev); 1012 } 1013 1014 if (status) 1015 gpiod_dbg(desc, "%s: status %d\n", __func__, status); 1016} 1017EXPORT_SYMBOL_GPL(gpiod_unexport); 1018 1019static int gpiochip_export(struct gpio_chip *chip) 1020{ 1021 int status; 1022 struct device *dev; 1023 1024 /* Many systems register gpio chips for SOC support very early, 1025 * before driver model support is available. In those cases we 1026 * export this later, in gpiolib_sysfs_init() ... here we just 1027 * verify that _some_ field of gpio_class got initialized. 1028 */ 1029 if (!gpio_class.p) 1030 return 0; 1031 1032 /* use chip->base for the ID; it's already known to be unique */ 1033 mutex_lock(&sysfs_lock); 1034 dev = device_create(&gpio_class, chip->dev, MKDEV(0, 0), chip, 1035 "gpiochip%d", chip->base); 1036 if (!IS_ERR(dev)) { 1037 status = sysfs_create_group(&dev->kobj, 1038 &gpiochip_attr_group); 1039 } else 1040 status = PTR_ERR(dev); 1041 chip->exported = (status == 0); 1042 mutex_unlock(&sysfs_lock); 1043 1044 if (status) { 1045 unsigned long flags; 1046 unsigned gpio; 1047 1048 spin_lock_irqsave(&gpio_lock, flags); 1049 gpio = 0; 1050 while (gpio < chip->ngpio) 1051 chip->desc[gpio++].chip = NULL; 1052 spin_unlock_irqrestore(&gpio_lock, flags); 1053 1054 chip_dbg(chip, "%s: status %d\n", __func__, status); 1055 } 1056 1057 return status; 1058} 1059 1060static void gpiochip_unexport(struct gpio_chip *chip) 1061{ 1062 int status; 1063 struct device *dev; 1064 1065 mutex_lock(&sysfs_lock); 1066 dev = class_find_device(&gpio_class, NULL, chip, match_export); 1067 if (dev) { 1068 put_device(dev); 1069 device_unregister(dev); 1070 chip->exported = false; 1071 status = 0; 1072 } else 1073 status = -ENODEV; 1074 mutex_unlock(&sysfs_lock); 1075 1076 if (status) 1077 chip_dbg(chip, "%s: status %d\n", __func__, status); 1078} 1079 1080static int __init gpiolib_sysfs_init(void) 1081{ 1082 int status; 1083 unsigned long flags; 1084 struct gpio_chip *chip; 1085 1086 status = class_register(&gpio_class); 1087 if (status < 0) 1088 return status; 1089 1090 /* Scan and register the gpio_chips which registered very 1091 * early (e.g. before the class_register above was called). 1092 * 1093 * We run before arch_initcall() so chip->dev nodes can have 1094 * registered, and so arch_initcall() can always gpio_export(). 1095 */ 1096 spin_lock_irqsave(&gpio_lock, flags); 1097 list_for_each_entry(chip, &gpio_chips, list) { 1098 if (!chip || chip->exported) 1099 continue; 1100 1101 spin_unlock_irqrestore(&gpio_lock, flags); 1102 status = gpiochip_export(chip); 1103 spin_lock_irqsave(&gpio_lock, flags); 1104 } 1105 spin_unlock_irqrestore(&gpio_lock, flags); 1106 1107 1108 return status; 1109} 1110postcore_initcall(gpiolib_sysfs_init); 1111 1112#else 1113static inline int gpiochip_export(struct gpio_chip *chip) 1114{ 1115 return 0; 1116} 1117 1118static inline void gpiochip_unexport(struct gpio_chip *chip) 1119{ 1120} 1121 1122#endif /* CONFIG_GPIO_SYSFS */ 1123 1124/* 1125 * Add a new chip to the global chips list, keeping the list of chips sorted 1126 * by base order. 1127 * 1128 * Return -EBUSY if the new chip overlaps with some other chip's integer 1129 * space. 1130 */ 1131static int gpiochip_add_to_list(struct gpio_chip *chip) 1132{ 1133 struct list_head *pos = &gpio_chips; 1134 struct gpio_chip *_chip; 1135 int err = 0; 1136 1137 /* find where to insert our chip */ 1138 list_for_each(pos, &gpio_chips) { 1139 _chip = list_entry(pos, struct gpio_chip, list); 1140 /* shall we insert before _chip? */ 1141 if (_chip->base >= chip->base + chip->ngpio) 1142 break; 1143 } 1144 1145 /* are we stepping on the chip right before? */ 1146 if (pos != &gpio_chips && pos->prev != &gpio_chips) { 1147 _chip = list_entry(pos->prev, struct gpio_chip, list); 1148 if (_chip->base + _chip->ngpio > chip->base) { 1149 dev_err(chip->dev, 1150 "GPIO integer space overlap, cannot add chip\n"); 1151 err = -EBUSY; 1152 } 1153 } 1154 1155 if (!err) 1156 list_add_tail(&chip->list, pos); 1157 1158 return err; 1159} 1160 1161/** 1162 * gpiochip_add() - register a gpio_chip 1163 * @chip: the chip to register, with chip->base initialized 1164 * Context: potentially before irqs or kmalloc will work 1165 * 1166 * Returns a negative errno if the chip can't be registered, such as 1167 * because the chip->base is invalid or already associated with a 1168 * different chip. Otherwise it returns zero as a success code. 1169 * 1170 * When gpiochip_add() is called very early during boot, so that GPIOs 1171 * can be freely used, the chip->dev device must be registered before 1172 * the gpio framework's arch_initcall(). Otherwise sysfs initialization 1173 * for GPIOs will fail rudely. 1174 * 1175 * If chip->base is negative, this requests dynamic assignment of 1176 * a range of valid GPIOs. 1177 */ 1178int gpiochip_add(struct gpio_chip *chip) 1179{ 1180 unsigned long flags; 1181 int status = 0; 1182 unsigned id; 1183 int base = chip->base; 1184 1185 if ((!gpio_is_valid(base) || !gpio_is_valid(base + chip->ngpio - 1)) 1186 && base >= 0) { 1187 status = -EINVAL; 1188 goto fail; 1189 } 1190 1191 spin_lock_irqsave(&gpio_lock, flags); 1192 1193 if (base < 0) { 1194 base = gpiochip_find_base(chip->ngpio); 1195 if (base < 0) { 1196 status = base; 1197 goto unlock; 1198 } 1199 chip->base = base; 1200 } 1201 1202 status = gpiochip_add_to_list(chip); 1203 1204 if (status == 0) { 1205 chip->desc = &gpio_desc[chip->base]; 1206 1207 for (id = 0; id < chip->ngpio; id++) { 1208 struct gpio_desc *desc = &chip->desc[id]; 1209 desc->chip = chip; 1210 1211 /* REVISIT: most hardware initializes GPIOs as 1212 * inputs (often with pullups enabled) so power 1213 * usage is minimized. Linux code should set the 1214 * gpio direction first thing; but until it does, 1215 * and in case chip->get_direction is not set, 1216 * we may expose the wrong direction in sysfs. 1217 */ 1218 desc->flags = !chip->direction_input 1219 ? (1 << FLAG_IS_OUT) 1220 : 0; 1221 } 1222 } 1223 1224 spin_unlock_irqrestore(&gpio_lock, flags); 1225 1226#ifdef CONFIG_PINCTRL 1227 INIT_LIST_HEAD(&chip->pin_ranges); 1228#endif 1229 1230 of_gpiochip_add(chip); 1231 acpi_gpiochip_add(chip); 1232 1233 if (status) 1234 goto fail; 1235 1236 status = gpiochip_export(chip); 1237 if (status) 1238 goto fail; 1239 1240 pr_debug("%s: registered GPIOs %d to %d on device: %s\n", __func__, 1241 chip->base, chip->base + chip->ngpio - 1, 1242 chip->label ? : "generic"); 1243 1244 return 0; 1245 1246unlock: 1247 spin_unlock_irqrestore(&gpio_lock, flags); 1248fail: 1249 /* failures here can mean systems won't boot... */ 1250 pr_err("%s: GPIOs %d..%d (%s) failed to register\n", __func__, 1251 chip->base, chip->base + chip->ngpio - 1, 1252 chip->label ? : "generic"); 1253 return status; 1254} 1255EXPORT_SYMBOL_GPL(gpiochip_add); 1256 1257/* Forward-declaration */ 1258static void gpiochip_irqchip_remove(struct gpio_chip *gpiochip); 1259 1260/** 1261 * gpiochip_remove() - unregister a gpio_chip 1262 * @chip: the chip to unregister 1263 * 1264 * A gpio_chip with any GPIOs still requested may not be removed. 1265 */ 1266int gpiochip_remove(struct gpio_chip *chip) 1267{ 1268 unsigned long flags; 1269 int status = 0; 1270 unsigned id; 1271 1272 acpi_gpiochip_remove(chip); 1273 1274 spin_lock_irqsave(&gpio_lock, flags); 1275 1276 gpiochip_irqchip_remove(chip); 1277 gpiochip_remove_pin_ranges(chip); 1278 of_gpiochip_remove(chip); 1279 1280 for (id = 0; id < chip->ngpio; id++) { 1281 if (test_bit(FLAG_REQUESTED, &chip->desc[id].flags)) { 1282 status = -EBUSY; 1283 break; 1284 } 1285 } 1286 if (status == 0) { 1287 for (id = 0; id < chip->ngpio; id++) 1288 chip->desc[id].chip = NULL; 1289 1290 list_del(&chip->list); 1291 } 1292 1293 spin_unlock_irqrestore(&gpio_lock, flags); 1294 1295 if (status == 0) 1296 gpiochip_unexport(chip); 1297 1298 return status; 1299} 1300EXPORT_SYMBOL_GPL(gpiochip_remove); 1301 1302/** 1303 * gpiochip_find() - iterator for locating a specific gpio_chip 1304 * @data: data to pass to match function 1305 * @callback: Callback function to check gpio_chip 1306 * 1307 * Similar to bus_find_device. It returns a reference to a gpio_chip as 1308 * determined by a user supplied @match callback. The callback should return 1309 * 0 if the device doesn't match and non-zero if it does. If the callback is 1310 * non-zero, this function will return to the caller and not iterate over any 1311 * more gpio_chips. 1312 */ 1313struct gpio_chip *gpiochip_find(void *data, 1314 int (*match)(struct gpio_chip *chip, 1315 void *data)) 1316{ 1317 struct gpio_chip *chip; 1318 unsigned long flags; 1319 1320 spin_lock_irqsave(&gpio_lock, flags); 1321 list_for_each_entry(chip, &gpio_chips, list) 1322 if (match(chip, data)) 1323 break; 1324 1325 /* No match? */ 1326 if (&chip->list == &gpio_chips) 1327 chip = NULL; 1328 spin_unlock_irqrestore(&gpio_lock, flags); 1329 1330 return chip; 1331} 1332EXPORT_SYMBOL_GPL(gpiochip_find); 1333 1334static int gpiochip_match_name(struct gpio_chip *chip, void *data) 1335{ 1336 const char *name = data; 1337 1338 return !strcmp(chip->label, name); 1339} 1340 1341static struct gpio_chip *find_chip_by_name(const char *name) 1342{ 1343 return gpiochip_find((void *)name, gpiochip_match_name); 1344} 1345 1346#ifdef CONFIG_GPIOLIB_IRQCHIP 1347 1348/* 1349 * The following is irqchip helper code for gpiochips. 1350 */ 1351 1352/** 1353 * gpiochip_add_chained_irqchip() - adds a chained irqchip to a gpiochip 1354 * @gpiochip: the gpiochip to add the irqchip to 1355 * @irqchip: the irqchip to add to the gpiochip 1356 * @parent_irq: the irq number corresponding to the parent IRQ for this 1357 * chained irqchip 1358 * @parent_handler: the parent interrupt handler for the accumulated IRQ 1359 * coming out of the gpiochip 1360 */ 1361void gpiochip_set_chained_irqchip(struct gpio_chip *gpiochip, 1362 struct irq_chip *irqchip, 1363 int parent_irq, 1364 irq_flow_handler_t parent_handler) 1365{ 1366 if (gpiochip->can_sleep) { 1367 chip_err(gpiochip, "you cannot have chained interrupts on a chip that may sleep\n"); 1368 return; 1369 } 1370 1371 irq_set_chained_handler(parent_irq, parent_handler); 1372 /* 1373 * The parent irqchip is already using the chip_data for this 1374 * irqchip, so our callbacks simply use the handler_data. 1375 */ 1376 irq_set_handler_data(parent_irq, gpiochip); 1377} 1378EXPORT_SYMBOL_GPL(gpiochip_set_chained_irqchip); 1379 1380/** 1381 * gpiochip_irq_map() - maps an IRQ into a GPIO irqchip 1382 * @d: the irqdomain used by this irqchip 1383 * @irq: the global irq number used by this GPIO irqchip irq 1384 * @hwirq: the local IRQ/GPIO line offset on this gpiochip 1385 * 1386 * This function will set up the mapping for a certain IRQ line on a 1387 * gpiochip by assigning the gpiochip as chip data, and using the irqchip 1388 * stored inside the gpiochip. 1389 */ 1390static int gpiochip_irq_map(struct irq_domain *d, unsigned int irq, 1391 irq_hw_number_t hwirq) 1392{ 1393 struct gpio_chip *chip = d->host_data; 1394 1395 irq_set_chip_data(irq, chip); 1396 irq_set_chip_and_handler(irq, chip->irqchip, chip->irq_handler); 1397 /* Chips that can sleep need nested thread handlers */ 1398 if (chip->can_sleep) 1399 irq_set_nested_thread(irq, 1); 1400#ifdef CONFIG_ARM 1401 set_irq_flags(irq, IRQF_VALID); 1402#else 1403 irq_set_noprobe(irq); 1404#endif 1405 irq_set_irq_type(irq, chip->irq_default_type); 1406 1407 return 0; 1408} 1409 1410static void gpiochip_irq_unmap(struct irq_domain *d, unsigned int irq) 1411{ 1412 struct gpio_chip *chip = d->host_data; 1413 1414#ifdef CONFIG_ARM 1415 set_irq_flags(irq, 0); 1416#endif 1417 if (chip->can_sleep) 1418 irq_set_nested_thread(irq, 0); 1419 irq_set_chip_and_handler(irq, NULL, NULL); 1420 irq_set_chip_data(irq, NULL); 1421} 1422 1423static const struct irq_domain_ops gpiochip_domain_ops = { 1424 .map = gpiochip_irq_map, 1425 .unmap = gpiochip_irq_unmap, 1426 /* Virtually all GPIO irqchips are twocell:ed */ 1427 .xlate = irq_domain_xlate_twocell, 1428}; 1429 1430static int gpiochip_irq_reqres(struct irq_data *d) 1431{ 1432 struct gpio_chip *chip = irq_data_get_irq_chip_data(d); 1433 1434 if (gpio_lock_as_irq(chip, d->hwirq)) { 1435 chip_err(chip, 1436 "unable to lock HW IRQ %lu for IRQ\n", 1437 d->hwirq); 1438 return -EINVAL; 1439 } 1440 return 0; 1441} 1442 1443static void gpiochip_irq_relres(struct irq_data *d) 1444{ 1445 struct gpio_chip *chip = irq_data_get_irq_chip_data(d); 1446 1447 gpio_unlock_as_irq(chip, d->hwirq); 1448} 1449 1450static int gpiochip_to_irq(struct gpio_chip *chip, unsigned offset) 1451{ 1452 return irq_find_mapping(chip->irqdomain, offset); 1453} 1454 1455/** 1456 * gpiochip_irqchip_remove() - removes an irqchip added to a gpiochip 1457 * @gpiochip: the gpiochip to remove the irqchip from 1458 * 1459 * This is called only from gpiochip_remove() 1460 */ 1461static void gpiochip_irqchip_remove(struct gpio_chip *gpiochip) 1462{ 1463 unsigned int offset; 1464 1465 /* Remove all IRQ mappings and delete the domain */ 1466 if (gpiochip->irqdomain) { 1467 for (offset = 0; offset < gpiochip->ngpio; offset++) 1468 irq_dispose_mapping(gpiochip->irq_base + offset); 1469 irq_domain_remove(gpiochip->irqdomain); 1470 } 1471 1472 if (gpiochip->irqchip) { 1473 gpiochip->irqchip->irq_request_resources = NULL; 1474 gpiochip->irqchip->irq_release_resources = NULL; 1475 gpiochip->irqchip = NULL; 1476 } 1477} 1478 1479/** 1480 * gpiochip_irqchip_add() - adds an irqchip to a gpiochip 1481 * @gpiochip: the gpiochip to add the irqchip to 1482 * @irqchip: the irqchip to add to the gpiochip 1483 * @first_irq: if not dynamically assigned, the base (first) IRQ to 1484 * allocate gpiochip irqs from 1485 * @handler: the irq handler to use (often a predefined irq core function) 1486 * @type: the default type for IRQs on this irqchip 1487 * 1488 * This function closely associates a certain irqchip with a certain 1489 * gpiochip, providing an irq domain to translate the local IRQs to 1490 * global irqs in the gpiolib core, and making sure that the gpiochip 1491 * is passed as chip data to all related functions. Driver callbacks 1492 * need to use container_of() to get their local state containers back 1493 * from the gpiochip passed as chip data. An irqdomain will be stored 1494 * in the gpiochip that shall be used by the driver to handle IRQ number 1495 * translation. The gpiochip will need to be initialized and registered 1496 * before calling this function. 1497 * 1498 * This function will handle two cell:ed simple IRQs and assumes all 1499 * the pins on the gpiochip can generate a unique IRQ. Everything else 1500 * need to be open coded. 1501 */ 1502int gpiochip_irqchip_add(struct gpio_chip *gpiochip, 1503 struct irq_chip *irqchip, 1504 unsigned int first_irq, 1505 irq_flow_handler_t handler, 1506 unsigned int type) 1507{ 1508 struct device_node *of_node; 1509 unsigned int offset; 1510 unsigned irq_base = 0; 1511 1512 if (!gpiochip || !irqchip) 1513 return -EINVAL; 1514 1515 if (!gpiochip->dev) { 1516 pr_err("missing gpiochip .dev parent pointer\n"); 1517 return -EINVAL; 1518 } 1519 of_node = gpiochip->dev->of_node; 1520#ifdef CONFIG_OF_GPIO 1521 /* 1522 * If the gpiochip has an assigned OF node this takes precendence 1523 * FIXME: get rid of this and use gpiochip->dev->of_node everywhere 1524 */ 1525 if (gpiochip->of_node) 1526 of_node = gpiochip->of_node; 1527#endif 1528 gpiochip->irqchip = irqchip; 1529 gpiochip->irq_handler = handler; 1530 gpiochip->irq_default_type = type; 1531 gpiochip->to_irq = gpiochip_to_irq; 1532 gpiochip->irqdomain = irq_domain_add_simple(of_node, 1533 gpiochip->ngpio, first_irq, 1534 &gpiochip_domain_ops, gpiochip); 1535 if (!gpiochip->irqdomain) { 1536 gpiochip->irqchip = NULL; 1537 return -EINVAL; 1538 } 1539 irqchip->irq_request_resources = gpiochip_irq_reqres; 1540 irqchip->irq_release_resources = gpiochip_irq_relres; 1541 1542 /* 1543 * Prepare the mapping since the irqchip shall be orthogonal to 1544 * any gpiochip calls. If the first_irq was zero, this is 1545 * necessary to allocate descriptors for all IRQs. 1546 */ 1547 for (offset = 0; offset < gpiochip->ngpio; offset++) { 1548 irq_base = irq_create_mapping(gpiochip->irqdomain, offset); 1549 if (offset == 0) 1550 /* 1551 * Store the base into the gpiochip to be used when 1552 * unmapping the irqs. 1553 */ 1554 gpiochip->irq_base = irq_base; 1555 } 1556 1557 return 0; 1558} 1559EXPORT_SYMBOL_GPL(gpiochip_irqchip_add); 1560 1561#else /* CONFIG_GPIOLIB_IRQCHIP */ 1562 1563static void gpiochip_irqchip_remove(struct gpio_chip *gpiochip) {} 1564 1565#endif /* CONFIG_GPIOLIB_IRQCHIP */ 1566 1567#ifdef CONFIG_PINCTRL 1568 1569/** 1570 * gpiochip_add_pingroup_range() - add a range for GPIO <-> pin mapping 1571 * @chip: the gpiochip to add the range for 1572 * @pinctrl: the dev_name() of the pin controller to map to 1573 * @gpio_offset: the start offset in the current gpio_chip number space 1574 * @pin_group: name of the pin group inside the pin controller 1575 */ 1576int gpiochip_add_pingroup_range(struct gpio_chip *chip, 1577 struct pinctrl_dev *pctldev, 1578 unsigned int gpio_offset, const char *pin_group) 1579{ 1580 struct gpio_pin_range *pin_range; 1581 int ret; 1582 1583 pin_range = kzalloc(sizeof(*pin_range), GFP_KERNEL); 1584 if (!pin_range) { 1585 chip_err(chip, "failed to allocate pin ranges\n"); 1586 return -ENOMEM; 1587 } 1588 1589 /* Use local offset as range ID */ 1590 pin_range->range.id = gpio_offset; 1591 pin_range->range.gc = chip; 1592 pin_range->range.name = chip->label; 1593 pin_range->range.base = chip->base + gpio_offset; 1594 pin_range->pctldev = pctldev; 1595 1596 ret = pinctrl_get_group_pins(pctldev, pin_group, 1597 &pin_range->range.pins, 1598 &pin_range->range.npins); 1599 if (ret < 0) { 1600 kfree(pin_range); 1601 return ret; 1602 } 1603 1604 pinctrl_add_gpio_range(pctldev, &pin_range->range); 1605 1606 chip_dbg(chip, "created GPIO range %d->%d ==> %s PINGRP %s\n", 1607 gpio_offset, gpio_offset + pin_range->range.npins - 1, 1608 pinctrl_dev_get_devname(pctldev), pin_group); 1609 1610 list_add_tail(&pin_range->node, &chip->pin_ranges); 1611 1612 return 0; 1613} 1614EXPORT_SYMBOL_GPL(gpiochip_add_pingroup_range); 1615 1616/** 1617 * gpiochip_add_pin_range() - add a range for GPIO <-> pin mapping 1618 * @chip: the gpiochip to add the range for 1619 * @pinctrl_name: the dev_name() of the pin controller to map to 1620 * @gpio_offset: the start offset in the current gpio_chip number space 1621 * @pin_offset: the start offset in the pin controller number space 1622 * @npins: the number of pins from the offset of each pin space (GPIO and 1623 * pin controller) to accumulate in this range 1624 */ 1625int gpiochip_add_pin_range(struct gpio_chip *chip, const char *pinctl_name, 1626 unsigned int gpio_offset, unsigned int pin_offset, 1627 unsigned int npins) 1628{ 1629 struct gpio_pin_range *pin_range; 1630 int ret; 1631 1632 pin_range = kzalloc(sizeof(*pin_range), GFP_KERNEL); 1633 if (!pin_range) { 1634 chip_err(chip, "failed to allocate pin ranges\n"); 1635 return -ENOMEM; 1636 } 1637 1638 /* Use local offset as range ID */ 1639 pin_range->range.id = gpio_offset; 1640 pin_range->range.gc = chip; 1641 pin_range->range.name = chip->label; 1642 pin_range->range.base = chip->base + gpio_offset; 1643 pin_range->range.pin_base = pin_offset; 1644 pin_range->range.npins = npins; 1645 pin_range->pctldev = pinctrl_find_and_add_gpio_range(pinctl_name, 1646 &pin_range->range); 1647 if (IS_ERR(pin_range->pctldev)) { 1648 ret = PTR_ERR(pin_range->pctldev); 1649 chip_err(chip, "could not create pin range\n"); 1650 kfree(pin_range); 1651 return ret; 1652 } 1653 chip_dbg(chip, "created GPIO range %d->%d ==> %s PIN %d->%d\n", 1654 gpio_offset, gpio_offset + npins - 1, 1655 pinctl_name, 1656 pin_offset, pin_offset + npins - 1); 1657 1658 list_add_tail(&pin_range->node, &chip->pin_ranges); 1659 1660 return 0; 1661} 1662EXPORT_SYMBOL_GPL(gpiochip_add_pin_range); 1663 1664/** 1665 * gpiochip_remove_pin_ranges() - remove all the GPIO <-> pin mappings 1666 * @chip: the chip to remove all the mappings for 1667 */ 1668void gpiochip_remove_pin_ranges(struct gpio_chip *chip) 1669{ 1670 struct gpio_pin_range *pin_range, *tmp; 1671 1672 list_for_each_entry_safe(pin_range, tmp, &chip->pin_ranges, node) { 1673 list_del(&pin_range->node); 1674 pinctrl_remove_gpio_range(pin_range->pctldev, 1675 &pin_range->range); 1676 kfree(pin_range); 1677 } 1678} 1679EXPORT_SYMBOL_GPL(gpiochip_remove_pin_ranges); 1680 1681#endif /* CONFIG_PINCTRL */ 1682 1683/* These "optional" allocation calls help prevent drivers from stomping 1684 * on each other, and help provide better diagnostics in debugfs. 1685 * They're called even less than the "set direction" calls. 1686 */ 1687static int __gpiod_request(struct gpio_desc *desc, const char *label) 1688{ 1689 struct gpio_chip *chip = desc->chip; 1690 int status; 1691 unsigned long flags; 1692 1693 spin_lock_irqsave(&gpio_lock, flags); 1694 1695 /* NOTE: gpio_request() can be called in early boot, 1696 * before IRQs are enabled, for non-sleeping (SOC) GPIOs. 1697 */ 1698 1699 if (test_and_set_bit(FLAG_REQUESTED, &desc->flags) == 0) { 1700 desc_set_label(desc, label ? : "?"); 1701 status = 0; 1702 } else { 1703 status = -EBUSY; 1704 goto done; 1705 } 1706 1707 if (chip->request) { 1708 /* chip->request may sleep */ 1709 spin_unlock_irqrestore(&gpio_lock, flags); 1710 status = chip->request(chip, gpio_chip_hwgpio(desc)); 1711 spin_lock_irqsave(&gpio_lock, flags); 1712 1713 if (status < 0) { 1714 desc_set_label(desc, NULL); 1715 clear_bit(FLAG_REQUESTED, &desc->flags); 1716 goto done; 1717 } 1718 } 1719 if (chip->get_direction) { 1720 /* chip->get_direction may sleep */ 1721 spin_unlock_irqrestore(&gpio_lock, flags); 1722 gpiod_get_direction(desc); 1723 spin_lock_irqsave(&gpio_lock, flags); 1724 } 1725done: 1726 spin_unlock_irqrestore(&gpio_lock, flags); 1727 return status; 1728} 1729 1730static int gpiod_request(struct gpio_desc *desc, const char *label) 1731{ 1732 int status = -EPROBE_DEFER; 1733 struct gpio_chip *chip; 1734 1735 if (!desc) { 1736 pr_warn("%s: invalid GPIO\n", __func__); 1737 return -EINVAL; 1738 } 1739 1740 chip = desc->chip; 1741 if (!chip) 1742 goto done; 1743 1744 if (try_module_get(chip->owner)) { 1745 status = __gpiod_request(desc, label); 1746 if (status < 0) 1747 module_put(chip->owner); 1748 } 1749 1750done: 1751 if (status) 1752 gpiod_dbg(desc, "%s: status %d\n", __func__, status); 1753 1754 return status; 1755} 1756 1757int gpio_request(unsigned gpio, const char *label) 1758{ 1759 return gpiod_request(gpio_to_desc(gpio), label); 1760} 1761EXPORT_SYMBOL_GPL(gpio_request); 1762 1763static bool __gpiod_free(struct gpio_desc *desc) 1764{ 1765 bool ret = false; 1766 unsigned long flags; 1767 struct gpio_chip *chip; 1768 1769 might_sleep(); 1770 1771 gpiod_unexport(desc); 1772 1773 spin_lock_irqsave(&gpio_lock, flags); 1774 1775 chip = desc->chip; 1776 if (chip && test_bit(FLAG_REQUESTED, &desc->flags)) { 1777 if (chip->free) { 1778 spin_unlock_irqrestore(&gpio_lock, flags); 1779 might_sleep_if(chip->can_sleep); 1780 chip->free(chip, gpio_chip_hwgpio(desc)); 1781 spin_lock_irqsave(&gpio_lock, flags); 1782 } 1783 desc_set_label(desc, NULL); 1784 clear_bit(FLAG_ACTIVE_LOW, &desc->flags); 1785 clear_bit(FLAG_REQUESTED, &desc->flags); 1786 clear_bit(FLAG_OPEN_DRAIN, &desc->flags); 1787 clear_bit(FLAG_OPEN_SOURCE, &desc->flags); 1788 ret = true; 1789 } 1790 1791 spin_unlock_irqrestore(&gpio_lock, flags); 1792 return ret; 1793} 1794 1795static void gpiod_free(struct gpio_desc *desc) 1796{ 1797 if (desc && __gpiod_free(desc)) 1798 module_put(desc->chip->owner); 1799 else 1800 WARN_ON(extra_checks); 1801} 1802 1803void gpio_free(unsigned gpio) 1804{ 1805 gpiod_free(gpio_to_desc(gpio)); 1806} 1807EXPORT_SYMBOL_GPL(gpio_free); 1808 1809/** 1810 * gpio_request_one - request a single GPIO with initial configuration 1811 * @gpio: the GPIO number 1812 * @flags: GPIO configuration as specified by GPIOF_* 1813 * @label: a literal description string of this GPIO 1814 */ 1815int gpio_request_one(unsigned gpio, unsigned long flags, const char *label) 1816{ 1817 struct gpio_desc *desc; 1818 int err; 1819 1820 desc = gpio_to_desc(gpio); 1821 1822 err = gpiod_request(desc, label); 1823 if (err) 1824 return err; 1825 1826 if (flags & GPIOF_OPEN_DRAIN) 1827 set_bit(FLAG_OPEN_DRAIN, &desc->flags); 1828 1829 if (flags & GPIOF_OPEN_SOURCE) 1830 set_bit(FLAG_OPEN_SOURCE, &desc->flags); 1831 1832 if (flags & GPIOF_DIR_IN) 1833 err = gpiod_direction_input(desc); 1834 else 1835 err = gpiod_direction_output_raw(desc, 1836 (flags & GPIOF_INIT_HIGH) ? 1 : 0); 1837 1838 if (err) 1839 goto free_gpio; 1840 1841 if (flags & GPIOF_EXPORT) { 1842 err = gpiod_export(desc, flags & GPIOF_EXPORT_CHANGEABLE); 1843 if (err) 1844 goto free_gpio; 1845 } 1846 1847 return 0; 1848 1849 free_gpio: 1850 gpiod_free(desc); 1851 return err; 1852} 1853EXPORT_SYMBOL_GPL(gpio_request_one); 1854 1855/** 1856 * gpio_request_array - request multiple GPIOs in a single call 1857 * @array: array of the 'struct gpio' 1858 * @num: how many GPIOs in the array 1859 */ 1860int gpio_request_array(const struct gpio *array, size_t num) 1861{ 1862 int i, err; 1863 1864 for (i = 0; i < num; i++, array++) { 1865 err = gpio_request_one(array->gpio, array->flags, array->label); 1866 if (err) 1867 goto err_free; 1868 } 1869 return 0; 1870 1871err_free: 1872 while (i--) 1873 gpio_free((--array)->gpio); 1874 return err; 1875} 1876EXPORT_SYMBOL_GPL(gpio_request_array); 1877 1878/** 1879 * gpio_free_array - release multiple GPIOs in a single call 1880 * @array: array of the 'struct gpio' 1881 * @num: how many GPIOs in the array 1882 */ 1883void gpio_free_array(const struct gpio *array, size_t num) 1884{ 1885 while (num--) 1886 gpio_free((array++)->gpio); 1887} 1888EXPORT_SYMBOL_GPL(gpio_free_array); 1889 1890/** 1891 * gpiochip_is_requested - return string iff signal was requested 1892 * @chip: controller managing the signal 1893 * @offset: of signal within controller's 0..(ngpio - 1) range 1894 * 1895 * Returns NULL if the GPIO is not currently requested, else a string. 1896 * If debugfs support is enabled, the string returned is the label passed 1897 * to gpio_request(); otherwise it is a meaningless constant. 1898 * 1899 * This function is for use by GPIO controller drivers. The label can 1900 * help with diagnostics, and knowing that the signal is used as a GPIO 1901 * can help avoid accidentally multiplexing it to another controller. 1902 */ 1903const char *gpiochip_is_requested(struct gpio_chip *chip, unsigned offset) 1904{ 1905 struct gpio_desc *desc; 1906 1907 if (!GPIO_OFFSET_VALID(chip, offset)) 1908 return NULL; 1909 1910 desc = &chip->desc[offset]; 1911 1912 if (test_bit(FLAG_REQUESTED, &desc->flags) == 0) 1913 return NULL; 1914#ifdef CONFIG_DEBUG_FS 1915 return desc->label; 1916#else 1917 return "?"; 1918#endif 1919} 1920EXPORT_SYMBOL_GPL(gpiochip_is_requested); 1921 1922/** 1923 * gpiochip_request_own_desc - Allow GPIO chip to request its own descriptor 1924 * @desc: GPIO descriptor to request 1925 * @label: label for the GPIO 1926 * 1927 * Function allows GPIO chip drivers to request and use their own GPIO 1928 * descriptors via gpiolib API. Difference to gpiod_request() is that this 1929 * function will not increase reference count of the GPIO chip module. This 1930 * allows the GPIO chip module to be unloaded as needed (we assume that the 1931 * GPIO chip driver handles freeing the GPIOs it has requested). 1932 */ 1933int gpiochip_request_own_desc(struct gpio_desc *desc, const char *label) 1934{ 1935 if (!desc || !desc->chip) 1936 return -EINVAL; 1937 1938 return __gpiod_request(desc, label); 1939} 1940 1941/** 1942 * gpiochip_free_own_desc - Free GPIO requested by the chip driver 1943 * @desc: GPIO descriptor to free 1944 * 1945 * Function frees the given GPIO requested previously with 1946 * gpiochip_request_own_desc(). 1947 */ 1948void gpiochip_free_own_desc(struct gpio_desc *desc) 1949{ 1950 if (desc) 1951 __gpiod_free(desc); 1952} 1953 1954/* Drivers MUST set GPIO direction before making get/set calls. In 1955 * some cases this is done in early boot, before IRQs are enabled. 1956 * 1957 * As a rule these aren't called more than once (except for drivers 1958 * using the open-drain emulation idiom) so these are natural places 1959 * to accumulate extra debugging checks. Note that we can't (yet) 1960 * rely on gpio_request() having been called beforehand. 1961 */ 1962 1963/** 1964 * gpiod_direction_input - set the GPIO direction to input 1965 * @desc: GPIO to set to input 1966 * 1967 * Set the direction of the passed GPIO to input, such as gpiod_get_value() can 1968 * be called safely on it. 1969 * 1970 * Return 0 in case of success, else an error code. 1971 */ 1972int gpiod_direction_input(struct gpio_desc *desc) 1973{ 1974 unsigned long flags; 1975 struct gpio_chip *chip; 1976 int status = -EINVAL; 1977 int offset; 1978 1979 if (!desc || !desc->chip) { 1980 pr_warn("%s: invalid GPIO\n", __func__); 1981 return -EINVAL; 1982 } 1983 1984 chip = desc->chip; 1985 if (!chip->get || !chip->direction_input) { 1986 gpiod_warn(desc, 1987 "%s: missing get() or direction_input() operations\n", 1988 __func__); 1989 return -EIO; 1990 } 1991 1992 spin_lock_irqsave(&gpio_lock, flags); 1993 1994 status = gpio_ensure_requested(desc); 1995 if (status < 0) 1996 goto fail; 1997 1998 /* now we know the gpio is valid and chip won't vanish */ 1999 2000 spin_unlock_irqrestore(&gpio_lock, flags); 2001 2002 might_sleep_if(chip->can_sleep); 2003 2004 offset = gpio_chip_hwgpio(desc); 2005 if (status) { 2006 status = chip->request(chip, offset); 2007 if (status < 0) { 2008 gpiod_dbg(desc, "%s: chip request fail, %d\n", 2009 __func__, status); 2010 /* and it's not available to anyone else ... 2011 * gpio_request() is the fully clean solution. 2012 */ 2013 goto lose; 2014 } 2015 } 2016 2017 status = chip->direction_input(chip, offset); 2018 if (status == 0) 2019 clear_bit(FLAG_IS_OUT, &desc->flags); 2020 2021 trace_gpio_direction(desc_to_gpio(desc), 1, status); 2022lose: 2023 return status; 2024fail: 2025 spin_unlock_irqrestore(&gpio_lock, flags); 2026 if (status) 2027 gpiod_dbg(desc, "%s: status %d\n", __func__, status); 2028 return status; 2029} 2030EXPORT_SYMBOL_GPL(gpiod_direction_input); 2031 2032static int _gpiod_direction_output_raw(struct gpio_desc *desc, int value) 2033{ 2034 unsigned long flags; 2035 struct gpio_chip *chip; 2036 int status = -EINVAL; 2037 int offset; 2038 2039 /* GPIOs used for IRQs shall not be set as output */ 2040 if (test_bit(FLAG_USED_AS_IRQ, &desc->flags)) { 2041 gpiod_err(desc, 2042 "%s: tried to set a GPIO tied to an IRQ as output\n", 2043 __func__); 2044 return -EIO; 2045 } 2046 2047 /* Open drain pin should not be driven to 1 */ 2048 if (value && test_bit(FLAG_OPEN_DRAIN, &desc->flags)) 2049 return gpiod_direction_input(desc); 2050 2051 /* Open source pin should not be driven to 0 */ 2052 if (!value && test_bit(FLAG_OPEN_SOURCE, &desc->flags)) 2053 return gpiod_direction_input(desc); 2054 2055 chip = desc->chip; 2056 if (!chip->set || !chip->direction_output) { 2057 gpiod_warn(desc, 2058 "%s: missing set() or direction_output() operations\n", 2059 __func__); 2060 return -EIO; 2061 } 2062 2063 spin_lock_irqsave(&gpio_lock, flags); 2064 2065 status = gpio_ensure_requested(desc); 2066 if (status < 0) 2067 goto fail; 2068 2069 /* now we know the gpio is valid and chip won't vanish */ 2070 2071 spin_unlock_irqrestore(&gpio_lock, flags); 2072 2073 might_sleep_if(chip->can_sleep); 2074 2075 offset = gpio_chip_hwgpio(desc); 2076 if (status) { 2077 status = chip->request(chip, offset); 2078 if (status < 0) { 2079 gpiod_dbg(desc, "%s: chip request fail, %d\n", 2080 __func__, status); 2081 /* and it's not available to anyone else ... 2082 * gpio_request() is the fully clean solution. 2083 */ 2084 goto lose; 2085 } 2086 } 2087 2088 status = chip->direction_output(chip, offset, value); 2089 if (status == 0) 2090 set_bit(FLAG_IS_OUT, &desc->flags); 2091 trace_gpio_value(desc_to_gpio(desc), 0, value); 2092 trace_gpio_direction(desc_to_gpio(desc), 0, status); 2093lose: 2094 return status; 2095fail: 2096 spin_unlock_irqrestore(&gpio_lock, flags); 2097 if (status) 2098 gpiod_dbg(desc, "%s: gpio status %d\n", __func__, status); 2099 return status; 2100} 2101 2102/** 2103 * gpiod_direction_output_raw - set the GPIO direction to output 2104 * @desc: GPIO to set to output 2105 * @value: initial output value of the GPIO 2106 * 2107 * Set the direction of the passed GPIO to output, such as gpiod_set_value() can 2108 * be called safely on it. The initial value of the output must be specified 2109 * as raw value on the physical line without regard for the ACTIVE_LOW status. 2110 * 2111 * Return 0 in case of success, else an error code. 2112 */ 2113int gpiod_direction_output_raw(struct gpio_desc *desc, int value) 2114{ 2115 if (!desc || !desc->chip) { 2116 pr_warn("%s: invalid GPIO\n", __func__); 2117 return -EINVAL; 2118 } 2119 return _gpiod_direction_output_raw(desc, value); 2120} 2121EXPORT_SYMBOL_GPL(gpiod_direction_output_raw); 2122 2123/** 2124 * gpiod_direction_output - set the GPIO direction to output 2125 * @desc: GPIO to set to output 2126 * @value: initial output value of the GPIO 2127 * 2128 * Set the direction of the passed GPIO to output, such as gpiod_set_value() can 2129 * be called safely on it. The initial value of the output must be specified 2130 * as the logical value of the GPIO, i.e. taking its ACTIVE_LOW status into 2131 * account. 2132 * 2133 * Return 0 in case of success, else an error code. 2134 */ 2135int gpiod_direction_output(struct gpio_desc *desc, int value) 2136{ 2137 if (!desc || !desc->chip) { 2138 pr_warn("%s: invalid GPIO\n", __func__); 2139 return -EINVAL; 2140 } 2141 if (test_bit(FLAG_ACTIVE_LOW, &desc->flags)) 2142 value = !value; 2143 return _gpiod_direction_output_raw(desc, value); 2144} 2145EXPORT_SYMBOL_GPL(gpiod_direction_output); 2146 2147/** 2148 * gpiod_set_debounce - sets @debounce time for a @gpio 2149 * @gpio: the gpio to set debounce time 2150 * @debounce: debounce time is microseconds 2151 * 2152 * returns -ENOTSUPP if the controller does not support setting 2153 * debounce. 2154 */ 2155int gpiod_set_debounce(struct gpio_desc *desc, unsigned debounce) 2156{ 2157 unsigned long flags; 2158 struct gpio_chip *chip; 2159 int status = -EINVAL; 2160 int offset; 2161 2162 if (!desc || !desc->chip) { 2163 pr_warn("%s: invalid GPIO\n", __func__); 2164 return -EINVAL; 2165 } 2166 2167 chip = desc->chip; 2168 if (!chip->set || !chip->set_debounce) { 2169 gpiod_dbg(desc, 2170 "%s: missing set() or set_debounce() operations\n", 2171 __func__); 2172 return -ENOTSUPP; 2173 } 2174 2175 spin_lock_irqsave(&gpio_lock, flags); 2176 2177 status = gpio_ensure_requested(desc); 2178 if (status < 0) 2179 goto fail; 2180 2181 /* now we know the gpio is valid and chip won't vanish */ 2182 2183 spin_unlock_irqrestore(&gpio_lock, flags); 2184 2185 might_sleep_if(chip->can_sleep); 2186 2187 offset = gpio_chip_hwgpio(desc); 2188 return chip->set_debounce(chip, offset, debounce); 2189 2190fail: 2191 spin_unlock_irqrestore(&gpio_lock, flags); 2192 if (status) 2193 gpiod_dbg(desc, "%s: status %d\n", __func__, status); 2194 2195 return status; 2196} 2197EXPORT_SYMBOL_GPL(gpiod_set_debounce); 2198 2199/** 2200 * gpiod_is_active_low - test whether a GPIO is active-low or not 2201 * @desc: the gpio descriptor to test 2202 * 2203 * Returns 1 if the GPIO is active-low, 0 otherwise. 2204 */ 2205int gpiod_is_active_low(const struct gpio_desc *desc) 2206{ 2207 return test_bit(FLAG_ACTIVE_LOW, &desc->flags); 2208} 2209EXPORT_SYMBOL_GPL(gpiod_is_active_low); 2210 2211/* I/O calls are only valid after configuration completed; the relevant 2212 * "is this a valid GPIO" error checks should already have been done. 2213 * 2214 * "Get" operations are often inlinable as reading a pin value register, 2215 * and masking the relevant bit in that register. 2216 * 2217 * When "set" operations are inlinable, they involve writing that mask to 2218 * one register to set a low value, or a different register to set it high. 2219 * Otherwise locking is needed, so there may be little value to inlining. 2220 * 2221 *------------------------------------------------------------------------ 2222 * 2223 * IMPORTANT!!! The hot paths -- get/set value -- assume that callers 2224 * have requested the GPIO. That can include implicit requesting by 2225 * a direction setting call. Marking a gpio as requested locks its chip 2226 * in memory, guaranteeing that these table lookups need no more locking 2227 * and that gpiochip_remove() will fail. 2228 * 2229 * REVISIT when debugging, consider adding some instrumentation to ensure 2230 * that the GPIO was actually requested. 2231 */ 2232 2233static bool _gpiod_get_raw_value(const struct gpio_desc *desc) 2234{ 2235 struct gpio_chip *chip; 2236 bool value; 2237 int offset; 2238 2239 chip = desc->chip; 2240 offset = gpio_chip_hwgpio(desc); 2241 value = chip->get ? chip->get(chip, offset) : false; 2242 trace_gpio_value(desc_to_gpio(desc), 1, value); 2243 return value; 2244} 2245 2246/** 2247 * gpiod_get_raw_value() - return a gpio's raw value 2248 * @desc: gpio whose value will be returned 2249 * 2250 * Return the GPIO's raw value, i.e. the value of the physical line disregarding 2251 * its ACTIVE_LOW status. 2252 * 2253 * This function should be called from contexts where we cannot sleep, and will 2254 * complain if the GPIO chip functions potentially sleep. 2255 */ 2256int gpiod_get_raw_value(const struct gpio_desc *desc) 2257{ 2258 if (!desc) 2259 return 0; 2260 /* Should be using gpio_get_value_cansleep() */ 2261 WARN_ON(desc->chip->can_sleep); 2262 return _gpiod_get_raw_value(desc); 2263} 2264EXPORT_SYMBOL_GPL(gpiod_get_raw_value); 2265 2266/** 2267 * gpiod_get_value() - return a gpio's value 2268 * @desc: gpio whose value will be returned 2269 * 2270 * Return the GPIO's logical value, i.e. taking the ACTIVE_LOW status into 2271 * account. 2272 * 2273 * This function should be called from contexts where we cannot sleep, and will 2274 * complain if the GPIO chip functions potentially sleep. 2275 */ 2276int gpiod_get_value(const struct gpio_desc *desc) 2277{ 2278 int value; 2279 if (!desc) 2280 return 0; 2281 /* Should be using gpio_get_value_cansleep() */ 2282 WARN_ON(desc->chip->can_sleep); 2283 2284 value = _gpiod_get_raw_value(desc); 2285 if (test_bit(FLAG_ACTIVE_LOW, &desc->flags)) 2286 value = !value; 2287 2288 return value; 2289} 2290EXPORT_SYMBOL_GPL(gpiod_get_value); 2291 2292/* 2293 * _gpio_set_open_drain_value() - Set the open drain gpio's value. 2294 * @desc: gpio descriptor whose state need to be set. 2295 * @value: Non-zero for setting it HIGH otherise it will set to LOW. 2296 */ 2297static void _gpio_set_open_drain_value(struct gpio_desc *desc, bool value) 2298{ 2299 int err = 0; 2300 struct gpio_chip *chip = desc->chip; 2301 int offset = gpio_chip_hwgpio(desc); 2302 2303 if (value) { 2304 err = chip->direction_input(chip, offset); 2305 if (!err) 2306 clear_bit(FLAG_IS_OUT, &desc->flags); 2307 } else { 2308 err = chip->direction_output(chip, offset, 0); 2309 if (!err) 2310 set_bit(FLAG_IS_OUT, &desc->flags); 2311 } 2312 trace_gpio_direction(desc_to_gpio(desc), value, err); 2313 if (err < 0) 2314 gpiod_err(desc, 2315 "%s: Error in set_value for open drain err %d\n", 2316 __func__, err); 2317} 2318 2319/* 2320 * _gpio_set_open_source_value() - Set the open source gpio's value. 2321 * @desc: gpio descriptor whose state need to be set. 2322 * @value: Non-zero for setting it HIGH otherise it will set to LOW. 2323 */ 2324static void _gpio_set_open_source_value(struct gpio_desc *desc, bool value) 2325{ 2326 int err = 0; 2327 struct gpio_chip *chip = desc->chip; 2328 int offset = gpio_chip_hwgpio(desc); 2329 2330 if (value) { 2331 err = chip->direction_output(chip, offset, 1); 2332 if (!err) 2333 set_bit(FLAG_IS_OUT, &desc->flags); 2334 } else { 2335 err = chip->direction_input(chip, offset); 2336 if (!err) 2337 clear_bit(FLAG_IS_OUT, &desc->flags); 2338 } 2339 trace_gpio_direction(desc_to_gpio(desc), !value, err); 2340 if (err < 0) 2341 gpiod_err(desc, 2342 "%s: Error in set_value for open source err %d\n", 2343 __func__, err); 2344} 2345 2346static void _gpiod_set_raw_value(struct gpio_desc *desc, bool value) 2347{ 2348 struct gpio_chip *chip; 2349 2350 chip = desc->chip; 2351 trace_gpio_value(desc_to_gpio(desc), 0, value); 2352 if (test_bit(FLAG_OPEN_DRAIN, &desc->flags)) 2353 _gpio_set_open_drain_value(desc, value); 2354 else if (test_bit(FLAG_OPEN_SOURCE, &desc->flags)) 2355 _gpio_set_open_source_value(desc, value); 2356 else 2357 chip->set(chip, gpio_chip_hwgpio(desc), value); 2358} 2359 2360/** 2361 * gpiod_set_raw_value() - assign a gpio's raw value 2362 * @desc: gpio whose value will be assigned 2363 * @value: value to assign 2364 * 2365 * Set the raw value of the GPIO, i.e. the value of its physical line without 2366 * regard for its ACTIVE_LOW status. 2367 * 2368 * This function should be called from contexts where we cannot sleep, and will 2369 * complain if the GPIO chip functions potentially sleep. 2370 */ 2371void gpiod_set_raw_value(struct gpio_desc *desc, int value) 2372{ 2373 if (!desc) 2374 return; 2375 /* Should be using gpio_set_value_cansleep() */ 2376 WARN_ON(desc->chip->can_sleep); 2377 _gpiod_set_raw_value(desc, value); 2378} 2379EXPORT_SYMBOL_GPL(gpiod_set_raw_value); 2380 2381/** 2382 * gpiod_set_value() - assign a gpio's value 2383 * @desc: gpio whose value will be assigned 2384 * @value: value to assign 2385 * 2386 * Set the logical value of the GPIO, i.e. taking its ACTIVE_LOW status into 2387 * account 2388 * 2389 * This function should be called from contexts where we cannot sleep, and will 2390 * complain if the GPIO chip functions potentially sleep. 2391 */ 2392void gpiod_set_value(struct gpio_desc *desc, int value) 2393{ 2394 if (!desc) 2395 return; 2396 /* Should be using gpio_set_value_cansleep() */ 2397 WARN_ON(desc->chip->can_sleep); 2398 if (test_bit(FLAG_ACTIVE_LOW, &desc->flags)) 2399 value = !value; 2400 _gpiod_set_raw_value(desc, value); 2401} 2402EXPORT_SYMBOL_GPL(gpiod_set_value); 2403 2404/** 2405 * gpiod_cansleep() - report whether gpio value access may sleep 2406 * @desc: gpio to check 2407 * 2408 */ 2409int gpiod_cansleep(const struct gpio_desc *desc) 2410{ 2411 if (!desc) 2412 return 0; 2413 return desc->chip->can_sleep; 2414} 2415EXPORT_SYMBOL_GPL(gpiod_cansleep); 2416 2417/** 2418 * gpiod_to_irq() - return the IRQ corresponding to a GPIO 2419 * @desc: gpio whose IRQ will be returned (already requested) 2420 * 2421 * Return the IRQ corresponding to the passed GPIO, or an error code in case of 2422 * error. 2423 */ 2424int gpiod_to_irq(const struct gpio_desc *desc) 2425{ 2426 struct gpio_chip *chip; 2427 int offset; 2428 2429 if (!desc) 2430 return -EINVAL; 2431 chip = desc->chip; 2432 offset = gpio_chip_hwgpio(desc); 2433 return chip->to_irq ? chip->to_irq(chip, offset) : -ENXIO; 2434} 2435EXPORT_SYMBOL_GPL(gpiod_to_irq); 2436 2437/** 2438 * gpiod_lock_as_irq() - lock a GPIO to be used as IRQ 2439 * @gpio: the GPIO line to lock as used for IRQ 2440 * 2441 * This is used directly by GPIO drivers that want to lock down 2442 * a certain GPIO line to be used for IRQs. 2443 */ 2444int gpiod_lock_as_irq(struct gpio_desc *desc) 2445{ 2446 if (!desc) 2447 return -EINVAL; 2448 2449 if (test_bit(FLAG_IS_OUT, &desc->flags)) { 2450 gpiod_err(desc, 2451 "%s: tried to flag a GPIO set as output for IRQ\n", 2452 __func__); 2453 return -EIO; 2454 } 2455 2456 set_bit(FLAG_USED_AS_IRQ, &desc->flags); 2457 return 0; 2458} 2459EXPORT_SYMBOL_GPL(gpiod_lock_as_irq); 2460 2461int gpio_lock_as_irq(struct gpio_chip *chip, unsigned int offset) 2462{ 2463 return gpiod_lock_as_irq(gpiochip_get_desc(chip, offset)); 2464} 2465EXPORT_SYMBOL_GPL(gpio_lock_as_irq); 2466 2467/** 2468 * gpiod_unlock_as_irq() - unlock a GPIO used as IRQ 2469 * @gpio: the GPIO line to unlock from IRQ usage 2470 * 2471 * This is used directly by GPIO drivers that want to indicate 2472 * that a certain GPIO is no longer used exclusively for IRQ. 2473 */ 2474void gpiod_unlock_as_irq(struct gpio_desc *desc) 2475{ 2476 if (!desc) 2477 return; 2478 2479 clear_bit(FLAG_USED_AS_IRQ, &desc->flags); 2480} 2481EXPORT_SYMBOL_GPL(gpiod_unlock_as_irq); 2482 2483void gpio_unlock_as_irq(struct gpio_chip *chip, unsigned int offset) 2484{ 2485 return gpiod_unlock_as_irq(gpiochip_get_desc(chip, offset)); 2486} 2487EXPORT_SYMBOL_GPL(gpio_unlock_as_irq); 2488 2489/** 2490 * gpiod_get_raw_value_cansleep() - return a gpio's raw value 2491 * @desc: gpio whose value will be returned 2492 * 2493 * Return the GPIO's raw value, i.e. the value of the physical line disregarding 2494 * its ACTIVE_LOW status. 2495 * 2496 * This function is to be called from contexts that can sleep. 2497 */ 2498int gpiod_get_raw_value_cansleep(const struct gpio_desc *desc) 2499{ 2500 might_sleep_if(extra_checks); 2501 if (!desc) 2502 return 0; 2503 return _gpiod_get_raw_value(desc); 2504} 2505EXPORT_SYMBOL_GPL(gpiod_get_raw_value_cansleep); 2506 2507/** 2508 * gpiod_get_value_cansleep() - return a gpio's value 2509 * @desc: gpio whose value will be returned 2510 * 2511 * Return the GPIO's logical value, i.e. taking the ACTIVE_LOW status into 2512 * account. 2513 * 2514 * This function is to be called from contexts that can sleep. 2515 */ 2516int gpiod_get_value_cansleep(const struct gpio_desc *desc) 2517{ 2518 int value; 2519 2520 might_sleep_if(extra_checks); 2521 if (!desc) 2522 return 0; 2523 2524 value = _gpiod_get_raw_value(desc); 2525 if (test_bit(FLAG_ACTIVE_LOW, &desc->flags)) 2526 value = !value; 2527 2528 return value; 2529} 2530EXPORT_SYMBOL_GPL(gpiod_get_value_cansleep); 2531 2532/** 2533 * gpiod_set_raw_value_cansleep() - assign a gpio's raw value 2534 * @desc: gpio whose value will be assigned 2535 * @value: value to assign 2536 * 2537 * Set the raw value of the GPIO, i.e. the value of its physical line without 2538 * regard for its ACTIVE_LOW status. 2539 * 2540 * This function is to be called from contexts that can sleep. 2541 */ 2542void gpiod_set_raw_value_cansleep(struct gpio_desc *desc, int value) 2543{ 2544 might_sleep_if(extra_checks); 2545 if (!desc) 2546 return; 2547 _gpiod_set_raw_value(desc, value); 2548} 2549EXPORT_SYMBOL_GPL(gpiod_set_raw_value_cansleep); 2550 2551/** 2552 * gpiod_set_value_cansleep() - assign a gpio's value 2553 * @desc: gpio whose value will be assigned 2554 * @value: value to assign 2555 * 2556 * Set the logical value of the GPIO, i.e. taking its ACTIVE_LOW status into 2557 * account 2558 * 2559 * This function is to be called from contexts that can sleep. 2560 */ 2561void gpiod_set_value_cansleep(struct gpio_desc *desc, int value) 2562{ 2563 might_sleep_if(extra_checks); 2564 if (!desc) 2565 return; 2566 2567 if (test_bit(FLAG_ACTIVE_LOW, &desc->flags)) 2568 value = !value; 2569 _gpiod_set_raw_value(desc, value); 2570} 2571EXPORT_SYMBOL_GPL(gpiod_set_value_cansleep); 2572 2573/** 2574 * gpiod_add_lookup_table() - register GPIO device consumers 2575 * @table: table of consumers to register 2576 */ 2577void gpiod_add_lookup_table(struct gpiod_lookup_table *table) 2578{ 2579 mutex_lock(&gpio_lookup_lock); 2580 2581 list_add_tail(&table->list, &gpio_lookup_list); 2582 2583 mutex_unlock(&gpio_lookup_lock); 2584} 2585 2586#ifdef CONFIG_OF 2587static struct gpio_desc *of_find_gpio(struct device *dev, const char *con_id, 2588 unsigned int idx, 2589 enum gpio_lookup_flags *flags) 2590{ 2591 char prop_name[32]; /* 32 is max size of property name */ 2592 enum of_gpio_flags of_flags; 2593 struct gpio_desc *desc; 2594 2595 if (con_id) 2596 snprintf(prop_name, 32, "%s-gpios", con_id); 2597 else 2598 snprintf(prop_name, 32, "gpios"); 2599 2600 desc = of_get_named_gpiod_flags(dev->of_node, prop_name, idx, 2601 &of_flags); 2602 2603 if (IS_ERR(desc)) 2604 return desc; 2605 2606 if (of_flags & OF_GPIO_ACTIVE_LOW) 2607 *flags |= GPIO_ACTIVE_LOW; 2608 2609 return desc; 2610} 2611#else 2612static struct gpio_desc *of_find_gpio(struct device *dev, const char *con_id, 2613 unsigned int idx, 2614 enum gpio_lookup_flags *flags) 2615{ 2616 return ERR_PTR(-ENODEV); 2617} 2618#endif 2619 2620static struct gpio_desc *acpi_find_gpio(struct device *dev, const char *con_id, 2621 unsigned int idx, 2622 enum gpio_lookup_flags *flags) 2623{ 2624 struct acpi_gpio_info info; 2625 struct gpio_desc *desc; 2626 2627 desc = acpi_get_gpiod_by_index(dev, idx, &info); 2628 if (IS_ERR(desc)) 2629 return desc; 2630 2631 if (info.gpioint && info.active_low) 2632 *flags |= GPIO_ACTIVE_LOW; 2633 2634 return desc; 2635} 2636 2637static struct gpiod_lookup_table *gpiod_find_lookup_table(struct device *dev) 2638{ 2639 const char *dev_id = dev ? dev_name(dev) : NULL; 2640 struct gpiod_lookup_table *table; 2641 2642 mutex_lock(&gpio_lookup_lock); 2643 2644 list_for_each_entry(table, &gpio_lookup_list, list) { 2645 if (table->dev_id && dev_id) { 2646 /* 2647 * Valid strings on both ends, must be identical to have 2648 * a match 2649 */ 2650 if (!strcmp(table->dev_id, dev_id)) 2651 goto found; 2652 } else { 2653 /* 2654 * One of the pointers is NULL, so both must be to have 2655 * a match 2656 */ 2657 if (dev_id == table->dev_id) 2658 goto found; 2659 } 2660 } 2661 table = NULL; 2662 2663found: 2664 mutex_unlock(&gpio_lookup_lock); 2665 return table; 2666} 2667 2668static struct gpio_desc *gpiod_find(struct device *dev, const char *con_id, 2669 unsigned int idx, 2670 enum gpio_lookup_flags *flags) 2671{ 2672 struct gpio_desc *desc = ERR_PTR(-ENOENT); 2673 struct gpiod_lookup_table *table; 2674 struct gpiod_lookup *p; 2675 2676 table = gpiod_find_lookup_table(dev); 2677 if (!table) 2678 return desc; 2679 2680 for (p = &table->table[0]; p->chip_label; p++) { 2681 struct gpio_chip *chip; 2682 2683 /* idx must always match exactly */ 2684 if (p->idx != idx) 2685 continue; 2686 2687 /* If the lookup entry has a con_id, require exact match */ 2688 if (p->con_id && (!con_id || strcmp(p->con_id, con_id))) 2689 continue; 2690 2691 chip = find_chip_by_name(p->chip_label); 2692 2693 if (!chip) { 2694 dev_err(dev, "cannot find GPIO chip %s\n", 2695 p->chip_label); 2696 return ERR_PTR(-ENODEV); 2697 } 2698 2699 if (chip->ngpio <= p->chip_hwnum) { 2700 dev_err(dev, 2701 "requested GPIO %d is out of range [0..%d] for chip %s\n", 2702 idx, chip->ngpio, chip->label); 2703 return ERR_PTR(-EINVAL); 2704 } 2705 2706 desc = gpiochip_get_desc(chip, p->chip_hwnum); 2707 *flags = p->flags; 2708 2709 return desc; 2710 } 2711 2712 return desc; 2713} 2714 2715/** 2716 * gpio_get - obtain a GPIO for a given GPIO function 2717 * @dev: GPIO consumer, can be NULL for system-global GPIOs 2718 * @con_id: function within the GPIO consumer 2719 * 2720 * Return the GPIO descriptor corresponding to the function con_id of device 2721 * dev, -ENOENT if no GPIO has been assigned to the requested function, or 2722 * another IS_ERR() code if an error occured while trying to acquire the GPIO. 2723 */ 2724struct gpio_desc *__must_check gpiod_get(struct device *dev, const char *con_id) 2725{ 2726 return gpiod_get_index(dev, con_id, 0); 2727} 2728EXPORT_SYMBOL_GPL(gpiod_get); 2729 2730/** 2731 * gpiod_get_index - obtain a GPIO from a multi-index GPIO function 2732 * @dev: GPIO consumer, can be NULL for system-global GPIOs 2733 * @con_id: function within the GPIO consumer 2734 * @idx: index of the GPIO to obtain in the consumer 2735 * 2736 * This variant of gpiod_get() allows to access GPIOs other than the first 2737 * defined one for functions that define several GPIOs. 2738 * 2739 * Return a valid GPIO descriptor, -ENOENT if no GPIO has been assigned to the 2740 * requested function and/or index, or another IS_ERR() code if an error 2741 * occured while trying to acquire the GPIO. 2742 */ 2743struct gpio_desc *__must_check gpiod_get_index(struct device *dev, 2744 const char *con_id, 2745 unsigned int idx) 2746{ 2747 struct gpio_desc *desc = NULL; 2748 int status; 2749 enum gpio_lookup_flags flags = 0; 2750 2751 dev_dbg(dev, "GPIO lookup for consumer %s\n", con_id); 2752 2753 /* Using device tree? */ 2754 if (IS_ENABLED(CONFIG_OF) && dev && dev->of_node) { 2755 dev_dbg(dev, "using device tree for GPIO lookup\n"); 2756 desc = of_find_gpio(dev, con_id, idx, &flags); 2757 } else if (IS_ENABLED(CONFIG_ACPI) && dev && ACPI_HANDLE(dev)) { 2758 dev_dbg(dev, "using ACPI for GPIO lookup\n"); 2759 desc = acpi_find_gpio(dev, con_id, idx, &flags); 2760 } 2761 2762 /* 2763 * Either we are not using DT or ACPI, or their lookup did not return 2764 * a result. In that case, use platform lookup as a fallback. 2765 */ 2766 if (!desc || desc == ERR_PTR(-ENOENT)) { 2767 dev_dbg(dev, "using lookup tables for GPIO lookup"); 2768 desc = gpiod_find(dev, con_id, idx, &flags); 2769 } 2770 2771 if (IS_ERR(desc)) { 2772 dev_dbg(dev, "lookup for GPIO %s failed\n", con_id); 2773 return desc; 2774 } 2775 2776 status = gpiod_request(desc, con_id); 2777 2778 if (status < 0) 2779 return ERR_PTR(status); 2780 2781 if (flags & GPIO_ACTIVE_LOW) 2782 set_bit(FLAG_ACTIVE_LOW, &desc->flags); 2783 if (flags & GPIO_OPEN_DRAIN) 2784 set_bit(FLAG_OPEN_DRAIN, &desc->flags); 2785 if (flags & GPIO_OPEN_SOURCE) 2786 set_bit(FLAG_OPEN_SOURCE, &desc->flags); 2787 2788 return desc; 2789} 2790EXPORT_SYMBOL_GPL(gpiod_get_index); 2791 2792/** 2793 * gpiod_put - dispose of a GPIO descriptor 2794 * @desc: GPIO descriptor to dispose of 2795 * 2796 * No descriptor can be used after gpiod_put() has been called on it. 2797 */ 2798void gpiod_put(struct gpio_desc *desc) 2799{ 2800 gpiod_free(desc); 2801} 2802EXPORT_SYMBOL_GPL(gpiod_put); 2803 2804#ifdef CONFIG_DEBUG_FS 2805 2806static void gpiolib_dbg_show(struct seq_file *s, struct gpio_chip *chip) 2807{ 2808 unsigned i; 2809 unsigned gpio = chip->base; 2810 struct gpio_desc *gdesc = &chip->desc[0]; 2811 int is_out; 2812 int is_irq; 2813 2814 for (i = 0; i < chip->ngpio; i++, gpio++, gdesc++) { 2815 if (!test_bit(FLAG_REQUESTED, &gdesc->flags)) 2816 continue; 2817 2818 gpiod_get_direction(gdesc); 2819 is_out = test_bit(FLAG_IS_OUT, &gdesc->flags); 2820 is_irq = test_bit(FLAG_USED_AS_IRQ, &gdesc->flags); 2821 seq_printf(s, " gpio-%-3d (%-20.20s) %s %s %s", 2822 gpio, gdesc->label, 2823 is_out ? "out" : "in ", 2824 chip->get 2825 ? (chip->get(chip, i) ? "hi" : "lo") 2826 : "? ", 2827 is_irq ? "IRQ" : " "); 2828 seq_printf(s, "\n"); 2829 } 2830} 2831 2832static void *gpiolib_seq_start(struct seq_file *s, loff_t *pos) 2833{ 2834 unsigned long flags; 2835 struct gpio_chip *chip = NULL; 2836 loff_t index = *pos; 2837 2838 s->private = ""; 2839 2840 spin_lock_irqsave(&gpio_lock, flags); 2841 list_for_each_entry(chip, &gpio_chips, list) 2842 if (index-- == 0) { 2843 spin_unlock_irqrestore(&gpio_lock, flags); 2844 return chip; 2845 } 2846 spin_unlock_irqrestore(&gpio_lock, flags); 2847 2848 return NULL; 2849} 2850 2851static void *gpiolib_seq_next(struct seq_file *s, void *v, loff_t *pos) 2852{ 2853 unsigned long flags; 2854 struct gpio_chip *chip = v; 2855 void *ret = NULL; 2856 2857 spin_lock_irqsave(&gpio_lock, flags); 2858 if (list_is_last(&chip->list, &gpio_chips)) 2859 ret = NULL; 2860 else 2861 ret = list_entry(chip->list.next, struct gpio_chip, list); 2862 spin_unlock_irqrestore(&gpio_lock, flags); 2863 2864 s->private = "\n"; 2865 ++*pos; 2866 2867 return ret; 2868} 2869 2870static void gpiolib_seq_stop(struct seq_file *s, void *v) 2871{ 2872} 2873 2874static int gpiolib_seq_show(struct seq_file *s, void *v) 2875{ 2876 struct gpio_chip *chip = v; 2877 struct device *dev; 2878 2879 seq_printf(s, "%sGPIOs %d-%d", (char *)s->private, 2880 chip->base, chip->base + chip->ngpio - 1); 2881 dev = chip->dev; 2882 if (dev) 2883 seq_printf(s, ", %s/%s", dev->bus ? dev->bus->name : "no-bus", 2884 dev_name(dev)); 2885 if (chip->label) 2886 seq_printf(s, ", %s", chip->label); 2887 if (chip->can_sleep) 2888 seq_printf(s, ", can sleep"); 2889 seq_printf(s, ":\n"); 2890 2891 if (chip->dbg_show) 2892 chip->dbg_show(s, chip); 2893 else 2894 gpiolib_dbg_show(s, chip); 2895 2896 return 0; 2897} 2898 2899static const struct seq_operations gpiolib_seq_ops = { 2900 .start = gpiolib_seq_start, 2901 .next = gpiolib_seq_next, 2902 .stop = gpiolib_seq_stop, 2903 .show = gpiolib_seq_show, 2904}; 2905 2906static int gpiolib_open(struct inode *inode, struct file *file) 2907{ 2908 return seq_open(file, &gpiolib_seq_ops); 2909} 2910 2911static const struct file_operations gpiolib_operations = { 2912 .owner = THIS_MODULE, 2913 .open = gpiolib_open, 2914 .read = seq_read, 2915 .llseek = seq_lseek, 2916 .release = seq_release, 2917}; 2918 2919static int __init gpiolib_debugfs_init(void) 2920{ 2921 /* /sys/kernel/debug/gpio */ 2922 (void) debugfs_create_file("gpio", S_IFREG | S_IRUGO, 2923 NULL, NULL, &gpiolib_operations); 2924 return 0; 2925} 2926subsys_initcall(gpiolib_debugfs_init); 2927 2928#endif /* DEBUG_FS */ 2929