David Brownell | d2876d0 | 2008-02-04 22:28:20 -0800 | [diff] [blame] | 1 | #include <linux/kernel.h> |
| 2 | #include <linux/module.h> |
| 3 | #include <linux/irq.h> |
| 4 | #include <linux/spinlock.h> |
| 5 | |
| 6 | #include <asm/gpio.h> |
| 7 | |
| 8 | |
| 9 | /* Optional implementation infrastructure for GPIO interfaces. |
| 10 | * |
| 11 | * Platforms may want to use this if they tend to use very many GPIOs |
| 12 | * that aren't part of a System-On-Chip core; or across I2C/SPI/etc. |
| 13 | * |
| 14 | * When kernel footprint or instruction count is an issue, simpler |
| 15 | * implementations may be preferred. The GPIO programming interface |
| 16 | * allows for inlining speed-critical get/set operations for common |
| 17 | * cases, so that access to SOC-integrated GPIOs can sometimes cost |
| 18 | * only an instruction or two per bit. |
| 19 | */ |
| 20 | |
| 21 | |
| 22 | /* When debugging, extend minimal trust to callers and platform code. |
| 23 | * Also emit diagnostic messages that may help initial bringup, when |
| 24 | * board setup or driver bugs are most common. |
| 25 | * |
| 26 | * Otherwise, minimize overhead in what may be bitbanging codepaths. |
| 27 | */ |
| 28 | #ifdef DEBUG |
| 29 | #define extra_checks 1 |
| 30 | #else |
| 31 | #define extra_checks 0 |
| 32 | #endif |
| 33 | |
| 34 | /* gpio_lock prevents conflicts during gpio_desc[] table updates. |
| 35 | * While any GPIO is requested, its gpio_chip is not removable; |
| 36 | * each GPIO's "requested" flag serves as a lock and refcount. |
| 37 | */ |
| 38 | static DEFINE_SPINLOCK(gpio_lock); |
| 39 | |
| 40 | struct gpio_desc { |
| 41 | struct gpio_chip *chip; |
| 42 | unsigned long flags; |
| 43 | /* flag symbols are bit numbers */ |
| 44 | #define FLAG_REQUESTED 0 |
| 45 | #define FLAG_IS_OUT 1 |
| 46 | |
| 47 | #ifdef CONFIG_DEBUG_FS |
| 48 | const char *label; |
| 49 | #endif |
| 50 | }; |
| 51 | static struct gpio_desc gpio_desc[ARCH_NR_GPIOS]; |
| 52 | |
| 53 | static inline void desc_set_label(struct gpio_desc *d, const char *label) |
| 54 | { |
| 55 | #ifdef CONFIG_DEBUG_FS |
| 56 | d->label = label; |
| 57 | #endif |
| 58 | } |
| 59 | |
| 60 | /* Warn when drivers omit gpio_request() calls -- legal but ill-advised |
| 61 | * when setting direction, and otherwise illegal. Until board setup code |
| 62 | * and drivers use explicit requests everywhere (which won't happen when |
| 63 | * those calls have no teeth) we can't avoid autorequesting. This nag |
| 64 | * message should motivate switching to explicit requests... |
| 65 | */ |
| 66 | static void gpio_ensure_requested(struct gpio_desc *desc) |
| 67 | { |
| 68 | if (test_and_set_bit(FLAG_REQUESTED, &desc->flags) == 0) { |
| 69 | pr_warning("GPIO-%d autorequested\n", (int)(desc - gpio_desc)); |
| 70 | desc_set_label(desc, "[auto]"); |
| 71 | } |
| 72 | } |
| 73 | |
| 74 | /* caller holds gpio_lock *OR* gpio is marked as requested */ |
| 75 | static inline struct gpio_chip *gpio_to_chip(unsigned gpio) |
| 76 | { |
| 77 | return gpio_desc[gpio].chip; |
| 78 | } |
| 79 | |
| 80 | /** |
| 81 | * gpiochip_add() - register a gpio_chip |
| 82 | * @chip: the chip to register, with chip->base initialized |
| 83 | * Context: potentially before irqs or kmalloc will work |
| 84 | * |
| 85 | * Returns a negative errno if the chip can't be registered, such as |
| 86 | * because the chip->base is invalid or already associated with a |
| 87 | * different chip. Otherwise it returns zero as a success code. |
| 88 | */ |
| 89 | int gpiochip_add(struct gpio_chip *chip) |
| 90 | { |
| 91 | unsigned long flags; |
| 92 | int status = 0; |
| 93 | unsigned id; |
| 94 | |
| 95 | /* NOTE chip->base negative is reserved to mean a request for |
| 96 | * dynamic allocation. We don't currently support that. |
| 97 | */ |
| 98 | |
| 99 | if (chip->base < 0 || (chip->base + chip->ngpio) >= ARCH_NR_GPIOS) { |
| 100 | status = -EINVAL; |
| 101 | goto fail; |
| 102 | } |
| 103 | |
| 104 | spin_lock_irqsave(&gpio_lock, flags); |
| 105 | |
| 106 | /* these GPIO numbers must not be managed by another gpio_chip */ |
| 107 | for (id = chip->base; id < chip->base + chip->ngpio; id++) { |
| 108 | if (gpio_desc[id].chip != NULL) { |
| 109 | status = -EBUSY; |
| 110 | break; |
| 111 | } |
| 112 | } |
| 113 | if (status == 0) { |
| 114 | for (id = chip->base; id < chip->base + chip->ngpio; id++) { |
| 115 | gpio_desc[id].chip = chip; |
| 116 | gpio_desc[id].flags = 0; |
| 117 | } |
| 118 | } |
| 119 | |
| 120 | spin_unlock_irqrestore(&gpio_lock, flags); |
| 121 | fail: |
| 122 | /* failures here can mean systems won't boot... */ |
| 123 | if (status) |
| 124 | pr_err("gpiochip_add: gpios %d..%d (%s) not registered\n", |
| 125 | chip->base, chip->base + chip->ngpio, |
| 126 | chip->label ? : "generic"); |
| 127 | return status; |
| 128 | } |
| 129 | EXPORT_SYMBOL_GPL(gpiochip_add); |
| 130 | |
| 131 | /** |
| 132 | * gpiochip_remove() - unregister a gpio_chip |
| 133 | * @chip: the chip to unregister |
| 134 | * |
| 135 | * A gpio_chip with any GPIOs still requested may not be removed. |
| 136 | */ |
| 137 | int gpiochip_remove(struct gpio_chip *chip) |
| 138 | { |
| 139 | unsigned long flags; |
| 140 | int status = 0; |
| 141 | unsigned id; |
| 142 | |
| 143 | spin_lock_irqsave(&gpio_lock, flags); |
| 144 | |
| 145 | for (id = chip->base; id < chip->base + chip->ngpio; id++) { |
| 146 | if (test_bit(FLAG_REQUESTED, &gpio_desc[id].flags)) { |
| 147 | status = -EBUSY; |
| 148 | break; |
| 149 | } |
| 150 | } |
| 151 | if (status == 0) { |
| 152 | for (id = chip->base; id < chip->base + chip->ngpio; id++) |
| 153 | gpio_desc[id].chip = NULL; |
| 154 | } |
| 155 | |
| 156 | spin_unlock_irqrestore(&gpio_lock, flags); |
| 157 | return status; |
| 158 | } |
| 159 | EXPORT_SYMBOL_GPL(gpiochip_remove); |
| 160 | |
| 161 | |
| 162 | /* These "optional" allocation calls help prevent drivers from stomping |
| 163 | * on each other, and help provide better diagnostics in debugfs. |
| 164 | * They're called even less than the "set direction" calls. |
| 165 | */ |
| 166 | int gpio_request(unsigned gpio, const char *label) |
| 167 | { |
| 168 | struct gpio_desc *desc; |
| 169 | int status = -EINVAL; |
| 170 | unsigned long flags; |
| 171 | |
| 172 | spin_lock_irqsave(&gpio_lock, flags); |
| 173 | |
| 174 | if (gpio >= ARCH_NR_GPIOS) |
| 175 | goto done; |
| 176 | desc = &gpio_desc[gpio]; |
| 177 | if (desc->chip == NULL) |
| 178 | goto done; |
| 179 | |
| 180 | /* NOTE: gpio_request() can be called in early boot, |
| 181 | * before IRQs are enabled. |
| 182 | */ |
| 183 | |
| 184 | if (test_and_set_bit(FLAG_REQUESTED, &desc->flags) == 0) { |
| 185 | desc_set_label(desc, label ? : "?"); |
| 186 | status = 0; |
| 187 | } else |
| 188 | status = -EBUSY; |
| 189 | |
| 190 | done: |
| 191 | if (status) |
| 192 | pr_debug("gpio_request: gpio-%d (%s) status %d\n", |
| 193 | gpio, label ? : "?", status); |
| 194 | spin_unlock_irqrestore(&gpio_lock, flags); |
| 195 | return status; |
| 196 | } |
| 197 | EXPORT_SYMBOL_GPL(gpio_request); |
| 198 | |
| 199 | void gpio_free(unsigned gpio) |
| 200 | { |
| 201 | unsigned long flags; |
| 202 | struct gpio_desc *desc; |
| 203 | |
| 204 | if (gpio >= ARCH_NR_GPIOS) { |
| 205 | WARN_ON(extra_checks); |
| 206 | return; |
| 207 | } |
| 208 | |
| 209 | spin_lock_irqsave(&gpio_lock, flags); |
| 210 | |
| 211 | desc = &gpio_desc[gpio]; |
| 212 | if (desc->chip && test_and_clear_bit(FLAG_REQUESTED, &desc->flags)) |
| 213 | desc_set_label(desc, NULL); |
| 214 | else |
| 215 | WARN_ON(extra_checks); |
| 216 | |
| 217 | spin_unlock_irqrestore(&gpio_lock, flags); |
| 218 | } |
| 219 | EXPORT_SYMBOL_GPL(gpio_free); |
| 220 | |
| 221 | |
| 222 | /** |
| 223 | * gpiochip_is_requested - return string iff signal was requested |
| 224 | * @chip: controller managing the signal |
| 225 | * @offset: of signal within controller's 0..(ngpio - 1) range |
| 226 | * |
| 227 | * Returns NULL if the GPIO is not currently requested, else a string. |
| 228 | * If debugfs support is enabled, the string returned is the label passed |
| 229 | * to gpio_request(); otherwise it is a meaningless constant. |
| 230 | * |
| 231 | * This function is for use by GPIO controller drivers. The label can |
| 232 | * help with diagnostics, and knowing that the signal is used as a GPIO |
| 233 | * can help avoid accidentally multiplexing it to another controller. |
| 234 | */ |
| 235 | const char *gpiochip_is_requested(struct gpio_chip *chip, unsigned offset) |
| 236 | { |
| 237 | unsigned gpio = chip->base + offset; |
| 238 | |
| 239 | if (gpio >= ARCH_NR_GPIOS || gpio_desc[gpio].chip != chip) |
| 240 | return NULL; |
| 241 | if (test_bit(FLAG_REQUESTED, &gpio_desc[gpio].flags) == 0) |
| 242 | return NULL; |
| 243 | #ifdef CONFIG_DEBUG_FS |
| 244 | return gpio_desc[gpio].label; |
| 245 | #else |
| 246 | return "?"; |
| 247 | #endif |
| 248 | } |
| 249 | EXPORT_SYMBOL_GPL(gpiochip_is_requested); |
| 250 | |
| 251 | |
| 252 | /* Drivers MUST set GPIO direction before making get/set calls. In |
| 253 | * some cases this is done in early boot, before IRQs are enabled. |
| 254 | * |
| 255 | * As a rule these aren't called more than once (except for drivers |
| 256 | * using the open-drain emulation idiom) so these are natural places |
| 257 | * to accumulate extra debugging checks. Note that we can't (yet) |
| 258 | * rely on gpio_request() having been called beforehand. |
| 259 | */ |
| 260 | |
| 261 | int gpio_direction_input(unsigned gpio) |
| 262 | { |
| 263 | unsigned long flags; |
| 264 | struct gpio_chip *chip; |
| 265 | struct gpio_desc *desc = &gpio_desc[gpio]; |
| 266 | int status = -EINVAL; |
| 267 | |
| 268 | spin_lock_irqsave(&gpio_lock, flags); |
| 269 | |
| 270 | if (gpio >= ARCH_NR_GPIOS) |
| 271 | goto fail; |
| 272 | chip = desc->chip; |
| 273 | if (!chip || !chip->get || !chip->direction_input) |
| 274 | goto fail; |
| 275 | gpio -= chip->base; |
| 276 | if (gpio >= chip->ngpio) |
| 277 | goto fail; |
| 278 | gpio_ensure_requested(desc); |
| 279 | |
| 280 | /* now we know the gpio is valid and chip won't vanish */ |
| 281 | |
| 282 | spin_unlock_irqrestore(&gpio_lock, flags); |
| 283 | |
| 284 | might_sleep_if(extra_checks && chip->can_sleep); |
| 285 | |
| 286 | status = chip->direction_input(chip, gpio); |
| 287 | if (status == 0) |
| 288 | clear_bit(FLAG_IS_OUT, &desc->flags); |
| 289 | return status; |
| 290 | fail: |
| 291 | spin_unlock_irqrestore(&gpio_lock, flags); |
| 292 | if (status) |
| 293 | pr_debug("%s: gpio-%d status %d\n", |
| 294 | __FUNCTION__, gpio, status); |
| 295 | return status; |
| 296 | } |
| 297 | EXPORT_SYMBOL_GPL(gpio_direction_input); |
| 298 | |
| 299 | int gpio_direction_output(unsigned gpio, int value) |
| 300 | { |
| 301 | unsigned long flags; |
| 302 | struct gpio_chip *chip; |
| 303 | struct gpio_desc *desc = &gpio_desc[gpio]; |
| 304 | int status = -EINVAL; |
| 305 | |
| 306 | spin_lock_irqsave(&gpio_lock, flags); |
| 307 | |
| 308 | if (gpio >= ARCH_NR_GPIOS) |
| 309 | goto fail; |
| 310 | chip = desc->chip; |
| 311 | if (!chip || !chip->set || !chip->direction_output) |
| 312 | goto fail; |
| 313 | gpio -= chip->base; |
| 314 | if (gpio >= chip->ngpio) |
| 315 | goto fail; |
| 316 | gpio_ensure_requested(desc); |
| 317 | |
| 318 | /* now we know the gpio is valid and chip won't vanish */ |
| 319 | |
| 320 | spin_unlock_irqrestore(&gpio_lock, flags); |
| 321 | |
| 322 | might_sleep_if(extra_checks && chip->can_sleep); |
| 323 | |
| 324 | status = chip->direction_output(chip, gpio, value); |
| 325 | if (status == 0) |
| 326 | set_bit(FLAG_IS_OUT, &desc->flags); |
| 327 | return status; |
| 328 | fail: |
| 329 | spin_unlock_irqrestore(&gpio_lock, flags); |
| 330 | if (status) |
| 331 | pr_debug("%s: gpio-%d status %d\n", |
| 332 | __FUNCTION__, gpio, status); |
| 333 | return status; |
| 334 | } |
| 335 | EXPORT_SYMBOL_GPL(gpio_direction_output); |
| 336 | |
| 337 | |
| 338 | /* I/O calls are only valid after configuration completed; the relevant |
| 339 | * "is this a valid GPIO" error checks should already have been done. |
| 340 | * |
| 341 | * "Get" operations are often inlinable as reading a pin value register, |
| 342 | * and masking the relevant bit in that register. |
| 343 | * |
| 344 | * When "set" operations are inlinable, they involve writing that mask to |
| 345 | * one register to set a low value, or a different register to set it high. |
| 346 | * Otherwise locking is needed, so there may be little value to inlining. |
| 347 | * |
| 348 | *------------------------------------------------------------------------ |
| 349 | * |
| 350 | * IMPORTANT!!! The hot paths -- get/set value -- assume that callers |
| 351 | * have requested the GPIO. That can include implicit requesting by |
| 352 | * a direction setting call. Marking a gpio as requested locks its chip |
| 353 | * in memory, guaranteeing that these table lookups need no more locking |
| 354 | * and that gpiochip_remove() will fail. |
| 355 | * |
| 356 | * REVISIT when debugging, consider adding some instrumentation to ensure |
| 357 | * that the GPIO was actually requested. |
| 358 | */ |
| 359 | |
| 360 | /** |
| 361 | * __gpio_get_value() - return a gpio's value |
| 362 | * @gpio: gpio whose value will be returned |
| 363 | * Context: any |
| 364 | * |
| 365 | * This is used directly or indirectly to implement gpio_get_value(). |
| 366 | * It returns the zero or nonzero value provided by the associated |
| 367 | * gpio_chip.get() method; or zero if no such method is provided. |
| 368 | */ |
| 369 | int __gpio_get_value(unsigned gpio) |
| 370 | { |
| 371 | struct gpio_chip *chip; |
| 372 | |
| 373 | chip = gpio_to_chip(gpio); |
| 374 | WARN_ON(extra_checks && chip->can_sleep); |
| 375 | return chip->get ? chip->get(chip, gpio - chip->base) : 0; |
| 376 | } |
| 377 | EXPORT_SYMBOL_GPL(__gpio_get_value); |
| 378 | |
| 379 | /** |
| 380 | * __gpio_set_value() - assign a gpio's value |
| 381 | * @gpio: gpio whose value will be assigned |
| 382 | * @value: value to assign |
| 383 | * Context: any |
| 384 | * |
| 385 | * This is used directly or indirectly to implement gpio_set_value(). |
| 386 | * It invokes the associated gpio_chip.set() method. |
| 387 | */ |
| 388 | void __gpio_set_value(unsigned gpio, int value) |
| 389 | { |
| 390 | struct gpio_chip *chip; |
| 391 | |
| 392 | chip = gpio_to_chip(gpio); |
| 393 | WARN_ON(extra_checks && chip->can_sleep); |
| 394 | chip->set(chip, gpio - chip->base, value); |
| 395 | } |
| 396 | EXPORT_SYMBOL_GPL(__gpio_set_value); |
| 397 | |
| 398 | /** |
| 399 | * __gpio_cansleep() - report whether gpio value access will sleep |
| 400 | * @gpio: gpio in question |
| 401 | * Context: any |
| 402 | * |
| 403 | * This is used directly or indirectly to implement gpio_cansleep(). It |
| 404 | * returns nonzero if access reading or writing the GPIO value can sleep. |
| 405 | */ |
| 406 | int __gpio_cansleep(unsigned gpio) |
| 407 | { |
| 408 | struct gpio_chip *chip; |
| 409 | |
| 410 | /* only call this on GPIOs that are valid! */ |
| 411 | chip = gpio_to_chip(gpio); |
| 412 | |
| 413 | return chip->can_sleep; |
| 414 | } |
| 415 | EXPORT_SYMBOL_GPL(__gpio_cansleep); |
| 416 | |
| 417 | |
| 418 | |
| 419 | /* There's no value in making it easy to inline GPIO calls that may sleep. |
| 420 | * Common examples include ones connected to I2C or SPI chips. |
| 421 | */ |
| 422 | |
| 423 | int gpio_get_value_cansleep(unsigned gpio) |
| 424 | { |
| 425 | struct gpio_chip *chip; |
| 426 | |
| 427 | might_sleep_if(extra_checks); |
| 428 | chip = gpio_to_chip(gpio); |
| 429 | return chip->get(chip, gpio - chip->base); |
| 430 | } |
| 431 | EXPORT_SYMBOL_GPL(gpio_get_value_cansleep); |
| 432 | |
| 433 | void gpio_set_value_cansleep(unsigned gpio, int value) |
| 434 | { |
| 435 | struct gpio_chip *chip; |
| 436 | |
| 437 | might_sleep_if(extra_checks); |
| 438 | chip = gpio_to_chip(gpio); |
| 439 | chip->set(chip, gpio - chip->base, value); |
| 440 | } |
| 441 | EXPORT_SYMBOL_GPL(gpio_set_value_cansleep); |
| 442 | |
| 443 | |
| 444 | #ifdef CONFIG_DEBUG_FS |
| 445 | |
| 446 | #include <linux/debugfs.h> |
| 447 | #include <linux/seq_file.h> |
| 448 | |
| 449 | |
| 450 | static void gpiolib_dbg_show(struct seq_file *s, struct gpio_chip *chip) |
| 451 | { |
| 452 | unsigned i; |
| 453 | unsigned gpio = chip->base; |
| 454 | struct gpio_desc *gdesc = &gpio_desc[gpio]; |
| 455 | int is_out; |
| 456 | |
| 457 | for (i = 0; i < chip->ngpio; i++, gpio++, gdesc++) { |
| 458 | if (!test_bit(FLAG_REQUESTED, &gdesc->flags)) |
| 459 | continue; |
| 460 | |
| 461 | is_out = test_bit(FLAG_IS_OUT, &gdesc->flags); |
| 462 | seq_printf(s, " gpio-%-3d (%-12s) %s %s", |
| 463 | gpio, gdesc->label, |
| 464 | is_out ? "out" : "in ", |
| 465 | chip->get |
| 466 | ? (chip->get(chip, i) ? "hi" : "lo") |
| 467 | : "? "); |
| 468 | |
| 469 | if (!is_out) { |
| 470 | int irq = gpio_to_irq(gpio); |
| 471 | struct irq_desc *desc = irq_desc + irq; |
| 472 | |
| 473 | /* This races with request_irq(), set_irq_type(), |
| 474 | * and set_irq_wake() ... but those are "rare". |
| 475 | * |
| 476 | * More significantly, trigger type flags aren't |
| 477 | * currently maintained by genirq. |
| 478 | */ |
| 479 | if (irq >= 0 && desc->action) { |
| 480 | char *trigger; |
| 481 | |
| 482 | switch (desc->status & IRQ_TYPE_SENSE_MASK) { |
| 483 | case IRQ_TYPE_NONE: |
| 484 | trigger = "(default)"; |
| 485 | break; |
| 486 | case IRQ_TYPE_EDGE_FALLING: |
| 487 | trigger = "edge-falling"; |
| 488 | break; |
| 489 | case IRQ_TYPE_EDGE_RISING: |
| 490 | trigger = "edge-rising"; |
| 491 | break; |
| 492 | case IRQ_TYPE_EDGE_BOTH: |
| 493 | trigger = "edge-both"; |
| 494 | break; |
| 495 | case IRQ_TYPE_LEVEL_HIGH: |
| 496 | trigger = "level-high"; |
| 497 | break; |
| 498 | case IRQ_TYPE_LEVEL_LOW: |
| 499 | trigger = "level-low"; |
| 500 | break; |
| 501 | default: |
| 502 | trigger = "?trigger?"; |
| 503 | break; |
| 504 | } |
| 505 | |
| 506 | seq_printf(s, " irq-%d %s%s", |
| 507 | irq, trigger, |
| 508 | (desc->status & IRQ_WAKEUP) |
| 509 | ? " wakeup" : ""); |
| 510 | } |
| 511 | } |
| 512 | |
| 513 | seq_printf(s, "\n"); |
| 514 | } |
| 515 | } |
| 516 | |
| 517 | static int gpiolib_show(struct seq_file *s, void *unused) |
| 518 | { |
| 519 | struct gpio_chip *chip = NULL; |
| 520 | unsigned gpio; |
| 521 | int started = 0; |
| 522 | |
| 523 | /* REVISIT this isn't locked against gpio_chip removal ... */ |
| 524 | |
| 525 | for (gpio = 0; gpio < ARCH_NR_GPIOS; gpio++) { |
| 526 | if (chip == gpio_desc[gpio].chip) |
| 527 | continue; |
| 528 | chip = gpio_desc[gpio].chip; |
| 529 | if (!chip) |
| 530 | continue; |
| 531 | |
| 532 | seq_printf(s, "%sGPIOs %d-%d, %s%s:\n", |
| 533 | started ? "\n" : "", |
| 534 | chip->base, chip->base + chip->ngpio - 1, |
| 535 | chip->label ? : "generic", |
| 536 | chip->can_sleep ? ", can sleep" : ""); |
| 537 | started = 1; |
| 538 | if (chip->dbg_show) |
| 539 | chip->dbg_show(s, chip); |
| 540 | else |
| 541 | gpiolib_dbg_show(s, chip); |
| 542 | } |
| 543 | return 0; |
| 544 | } |
| 545 | |
| 546 | static int gpiolib_open(struct inode *inode, struct file *file) |
| 547 | { |
| 548 | return single_open(file, gpiolib_show, NULL); |
| 549 | } |
| 550 | |
| 551 | static struct file_operations gpiolib_operations = { |
| 552 | .open = gpiolib_open, |
| 553 | .read = seq_read, |
| 554 | .llseek = seq_lseek, |
| 555 | .release = single_release, |
| 556 | }; |
| 557 | |
| 558 | static int __init gpiolib_debugfs_init(void) |
| 559 | { |
| 560 | /* /sys/kernel/debug/gpio */ |
| 561 | (void) debugfs_create_file("gpio", S_IFREG | S_IRUGO, |
| 562 | NULL, NULL, &gpiolib_operations); |
| 563 | return 0; |
| 564 | } |
| 565 | subsys_initcall(gpiolib_debugfs_init); |
| 566 | |
| 567 | #endif /* DEBUG_FS */ |