gpiolib.c 68.5 KB
Newer Older
1 2
#include <linux/kernel.h>
#include <linux/module.h>
3
#include <linux/interrupt.h>
4 5
#include <linux/irq.h>
#include <linux/spinlock.h>
6
#include <linux/list.h>
David Brownell's avatar
David Brownell committed
7 8 9 10 11
#include <linux/device.h>
#include <linux/err.h>
#include <linux/debugfs.h>
#include <linux/seq_file.h>
#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
#include <linux/gpio/machine.h>
18
#include <linux/pinctrl/consumer.h>
19

20 21
#include "gpiolib.h"

22 23
#define CREATE_TRACE_POINTS
#include <trace/events/gpio.h>
24

25
/* Implementation infrastructure for GPIO interfaces.
26
 *
27 28 29
 * The GPIO programming interface allows for inlining speed-critical
 * get/set operations for common cases, so that access to SOC-integrated
 * GPIOs can sometimes cost only an instruction or two per bit.
30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48
 */


/* When debugging, extend minimal trust to callers and platform code.
 * Also emit diagnostic messages that may help initial bringup, when
 * board setup or driver bugs are most common.
 *
 * Otherwise, minimize overhead in what may be bitbanging codepaths.
 */
#ifdef	DEBUG
#define	extra_checks	1
#else
#define	extra_checks	0
#endif

/* gpio_lock prevents conflicts during gpio_desc[] table updates.
 * While any GPIO is requested, its gpio_chip is not removable;
 * each GPIO's "requested" flag serves as a lock and refcount.
 */
49
DEFINE_SPINLOCK(gpio_lock);
50

51 52
static DEFINE_MUTEX(gpio_lookup_lock);
static LIST_HEAD(gpio_lookup_list);
53
LIST_HEAD(gpio_chips);
54

55 56 57 58 59

static void gpiochip_free_hogs(struct gpio_chip *chip);
static void gpiochip_irqchip_remove(struct gpio_chip *gpiochip);


60 61 62 63 64
static inline void desc_set_label(struct gpio_desc *d, const char *label)
{
	d->label = label;
}

65 66 67
/**
 * Convert a GPIO number to its descriptor
 */
68
struct gpio_desc *gpio_to_desc(unsigned gpio)
69
{
70 71 72 73 74 75 76 77 78 79 80 81 82 83
	struct gpio_chip *chip;
	unsigned long flags;

	spin_lock_irqsave(&gpio_lock, flags);

	list_for_each_entry(chip, &gpio_chips, list) {
		if (chip->base <= gpio && chip->base + chip->ngpio > gpio) {
			spin_unlock_irqrestore(&gpio_lock, flags);
			return &chip->desc[gpio - chip->base];
		}
	}

	spin_unlock_irqrestore(&gpio_lock, flags);

84 85 86
	if (!gpio_is_valid(gpio))
		WARN(1, "invalid GPIO %d\n", gpio);

87
	return NULL;
88
}
89
EXPORT_SYMBOL_GPL(gpio_to_desc);
90

91
/**
92
 * Get the GPIO descriptor corresponding to the given hw number for this chip.
93
 */
94 95
struct gpio_desc *gpiochip_get_desc(struct gpio_chip *chip,
				    u16 hwnum)
96
{
97
	if (hwnum >= chip->ngpio)
98
		return ERR_PTR(-EINVAL);
99

100
	return &chip->desc[hwnum];
101
}
102 103 104 105 106 107

/**
 * Convert a GPIO descriptor to the integer namespace.
 * This should disappear in the future but is needed since we still
 * use GPIO numbers for error messages and sysfs nodes
 */
108
int desc_to_gpio(const struct gpio_desc *desc)
109
{
110
	return desc->chip->base + (desc - &desc->chip->desc[0]);
111
}
112
EXPORT_SYMBOL_GPL(desc_to_gpio);
113 114


115 116 117 118 119
/**
 * gpiod_to_chip - Return the GPIO chip to which a GPIO descriptor belongs
 * @desc:	descriptor to return the chip of
 */
struct gpio_chip *gpiod_to_chip(const struct gpio_desc *desc)
120
{
121
	return desc ? desc->chip : NULL;
122
}
123
EXPORT_SYMBOL_GPL(gpiod_to_chip);
124

125 126 127
/* dynamic allocation of GPIOs, e.g. on a hotplugged device */
static int gpiochip_find_base(int ngpio)
{
128 129
	struct gpio_chip *chip;
	int base = ARCH_NR_GPIOS - ngpio;
130

131 132 133 134 135 136 137
	list_for_each_entry_reverse(chip, &gpio_chips, list) {
		/* found a free space? */
		if (chip->base + chip->ngpio <= base)
			break;
		else
			/* nope, check the space right before the chip */
			base = chip->base - ngpio;
138 139
	}

140
	if (gpio_is_valid(base)) {
141
		pr_debug("%s: found new base at %d\n", __func__, base);
142 143 144 145
		return base;
	} else {
		pr_err("%s: cannot find free range\n", __func__);
		return -ENOSPC;
Anton Vorontsov's avatar
Anton Vorontsov committed
146 147 148
	}
}

149 150 151 152 153 154 155 156
/**
 * gpiod_get_direction - return the current direction of a GPIO
 * @desc:	GPIO to get the direction of
 *
 * Return GPIOF_DIR_IN or GPIOF_DIR_OUT, or an error code in case of error.
 *
 * This function may sleep if gpiod_cansleep() is true.
 */
157
int gpiod_get_direction(struct gpio_desc *desc)
158 159
{
	struct gpio_chip	*chip;
160
	unsigned		offset;
161 162
	int			status = -EINVAL;

163 164
	chip = gpiod_to_chip(desc);
	offset = gpio_chip_hwgpio(desc);
165 166 167 168

	if (!chip->get_direction)
		return status;

169
	status = chip->get_direction(chip, offset);
170 171 172
	if (status > 0) {
		/* GPIOF_DIR_IN, or other positive */
		status = 1;
173
		clear_bit(FLAG_IS_OUT, &desc->flags);
174 175 176
	}
	if (status == 0) {
		/* GPIOF_DIR_OUT */
177
		set_bit(FLAG_IS_OUT, &desc->flags);
178 179 180
	}
	return status;
}
181
EXPORT_SYMBOL_GPL(gpiod_get_direction);
182

183 184
/*
 * Add a new chip to the global chips list, keeping the list of chips sorted
185
 * by range(means [base, base + ngpio - 1]) order.
186 187 188 189 190 191
 *
 * Return -EBUSY if the new chip overlaps with some other chip's integer
 * space.
 */
static int gpiochip_add_to_list(struct gpio_chip *chip)
{
192
	struct list_head *pos;
193 194
	struct gpio_chip *iterator;
	struct gpio_chip *previous = NULL;
195

196 197 198
	if (list_empty(&gpio_chips)) {
		pos = gpio_chips.next;
		goto found;
199 200
	}

201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219
	list_for_each(pos, &gpio_chips) {
		iterator = list_entry(pos, struct gpio_chip, list);
		if (iterator->base >= chip->base + chip->ngpio) {
			/*
			 * Iterator is the first GPIO chip so there is no
			 * previous one
			 */
			if (previous == NULL) {
				goto found;
			} else {
				/*
				 * We found a valid range(means
				 * [base, base + ngpio - 1]) between previous
				 * and iterator chip.
				 */
				if (previous->base + previous->ngpio
						<= chip->base)
					goto found;
			}
220
		}
221
		previous = iterator;
222 223
	}

224 225 226 227 228 229 230
	/* We are beyond the last chip in the list */
	if (iterator->base + iterator->ngpio <= chip->base)
		goto found;

	dev_err(chip->parent,
	       "GPIO integer space overlap, cannot add chip\n");
	return -EBUSY;
231

232 233 234
found:
	list_add_tail(&chip->list, pos);
	return 0;
235 236
}

237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267
/**
 * Convert a GPIO name to its descriptor
 */
static struct gpio_desc *gpio_name_to_desc(const char * const name)
{
	struct gpio_chip *chip;
	unsigned long flags;

	spin_lock_irqsave(&gpio_lock, flags);

	list_for_each_entry(chip, &gpio_chips, list) {
		int i;

		for (i = 0; i != chip->ngpio; ++i) {
			struct gpio_desc *gpio = &chip->desc[i];

			if (!gpio->name)
				continue;

			if (!strcmp(gpio->name, name)) {
				spin_unlock_irqrestore(&gpio_lock, flags);
				return gpio;
			}
		}
	}

	spin_unlock_irqrestore(&gpio_lock, flags);

	return NULL;
}

268 269 270 271
/*
 * Takes the names from gc->names and checks if they are all unique. If they
 * are, they are assigned to their gpio descriptors.
 *
272
 * Warning if one of the names is already used for a different GPIO.
273 274 275 276 277 278 279 280 281 282 283 284 285
 */
static int gpiochip_set_desc_names(struct gpio_chip *gc)
{
	int i;

	if (!gc->names)
		return 0;

	/* First check all names if they are unique */
	for (i = 0; i != gc->ngpio; ++i) {
		struct gpio_desc *gpio;

		gpio = gpio_name_to_desc(gc->names[i]);
286
		if (gpio)
287
			dev_warn(gc->parent, "Detected name collision for "
288 289
				 "GPIO name '%s'\n",
				 gc->names[i]);
290 291 292 293 294 295 296 297 298
	}

	/* Then add all names to the GPIO descriptors */
	for (i = 0; i != gc->ngpio; ++i)
		gc->desc[i].name = gc->names[i];

	return 0;
}

299 300 301
/**
 * gpiochip_add() - register a gpio_chip
 * @chip: the chip to register, with chip->base initialized
302
 * Context: potentially before irqs will work
303 304 305 306
 *
 * Returns a negative errno if the chip can't be registered, such as
 * because the chip->base is invalid or already associated with a
 * different chip.  Otherwise it returns zero as a success code.
307
 *
David Brownell's avatar
David Brownell committed
308 309 310 311 312
 * When gpiochip_add() is called very early during boot, so that GPIOs
 * can be freely used, the chip->dev device must be registered before
 * the gpio framework's arch_initcall().  Otherwise sysfs initialization
 * for GPIOs will fail rudely.
 *
313 314
 * If chip->base is negative, this requests dynamic assignment of
 * a range of valid GPIOs.
315 316 317 318 319 320
 */
int gpiochip_add(struct gpio_chip *chip)
{
	unsigned long	flags;
	int		status = 0;
	unsigned	id;
321
	int		base = chip->base;
322
	struct gpio_desc *descs;
323

324 325 326
	descs = kcalloc(chip->ngpio, sizeof(descs[0]), GFP_KERNEL);
	if (!descs)
		return -ENOMEM;
327

328 329 330 331 332
	if (chip->ngpio == 0) {
		chip_err(chip, "tried to insert a GPIO chip with zero lines\n");
		return -EINVAL;
	}

333 334
	spin_lock_irqsave(&gpio_lock, flags);

335 336 337 338
	if (base < 0) {
		base = gpiochip_find_base(chip->ngpio);
		if (base < 0) {
			status = base;
339 340
			spin_unlock_irqrestore(&gpio_lock, flags);
			goto err_free_descs;
341 342 343 344
		}
		chip->base = base;
	}

345
	status = gpiochip_add_to_list(chip);
346 347 348 349
	if (status) {
		spin_unlock_irqrestore(&gpio_lock, flags);
		goto err_free_descs;
	}
350

351 352 353 354 355 356 357 358 359 360 361 362
	for (id = 0; id < chip->ngpio; id++) {
		struct gpio_desc *desc = &descs[id];

		desc->chip = chip;

		/* REVISIT: most hardware initializes GPIOs as inputs (often
		 * with pullups enabled) so power usage is minimized. Linux
		 * code should set the gpio direction first thing; but until
		 * it does, and in case chip->get_direction is not set, we may
		 * expose the wrong direction in sysfs.
		 */
		desc->flags = !chip->direction_input ? (1 << FLAG_IS_OUT) : 0;
363 364
	}

365 366
	chip->desc = descs;

367 368
	spin_unlock_irqrestore(&gpio_lock, flags);

369 370 371 372
#ifdef CONFIG_PINCTRL
	INIT_LIST_HEAD(&chip->pin_ranges);
#endif

373 374
	if (!chip->owner && chip->parent && chip->parent->driver)
		chip->owner = chip->parent->driver->owner;
375

376 377 378 379
	status = gpiochip_set_desc_names(chip);
	if (status)
		goto err_remove_from_list;

380 381 382 383
	status = of_gpiochip_add(chip);
	if (status)
		goto err_remove_chip;

384
	acpi_gpiochip_add(chip);
385

386
	status = gpiochip_sysfs_register(chip);
387 388
	if (status)
		goto err_remove_chip;
389

390
	pr_debug("%s: registered GPIOs %d to %d on device: %s\n", __func__,
391 392 393
		chip->base, chip->base + chip->ngpio - 1,
		chip->label ? : "generic");

394
	return 0;
395

396 397
err_remove_chip:
	acpi_gpiochip_remove(chip);
398
	gpiochip_free_hogs(chip);
399
	of_gpiochip_remove(chip);
400
err_remove_from_list:
401 402
	spin_lock_irqsave(&gpio_lock, flags);
	list_del(&chip->list);
403
	spin_unlock_irqrestore(&gpio_lock, flags);
404
	chip->desc = NULL;
405
err_free_descs:
406 407
	kfree(descs);

408
	/* failures here can mean systems won't boot... */
409
	pr_err("%s: GPIOs %d..%d (%s) failed to register\n", __func__,
410 411
		chip->base, chip->base + chip->ngpio - 1,
		chip->label ? : "generic");
412 413 414 415 416 417 418 419 420 421
	return status;
}
EXPORT_SYMBOL_GPL(gpiochip_add);

/**
 * gpiochip_remove() - unregister a gpio_chip
 * @chip: the chip to unregister
 *
 * A gpio_chip with any GPIOs still requested may not be removed.
 */
422
void gpiochip_remove(struct gpio_chip *chip)
423
{
Johan Hovold's avatar
Johan Hovold committed
424
	struct gpio_desc *desc;
425 426
	unsigned long	flags;
	unsigned	id;
Johan Hovold's avatar
Johan Hovold committed
427
	bool		requested = false;
428

429
	gpiochip_sysfs_unregister(chip);
430

431 432
	gpiochip_irqchip_remove(chip);

433
	acpi_gpiochip_remove(chip);
434
	gpiochip_remove_pin_ranges(chip);
435
	gpiochip_free_hogs(chip);
436 437
	of_gpiochip_remove(chip);

438
	spin_lock_irqsave(&gpio_lock, flags);
439
	for (id = 0; id < chip->ngpio; id++) {
Johan Hovold's avatar
Johan Hovold committed
440 441 442 443
		desc = &chip->desc[id];
		desc->chip = NULL;
		if (test_bit(FLAG_REQUESTED, &desc->flags))
			requested = true;
444
	}
445
	list_del(&chip->list);
446
	spin_unlock_irqrestore(&gpio_lock, flags);
447

Johan Hovold's avatar
Johan Hovold committed
448
	if (requested)
449 450
		dev_crit(chip->parent,
			 "REMOVING GPIOCHIP WITH GPIOS STILL REQUESTED\n");
Johan Hovold's avatar
Johan Hovold committed
451

452 453
	kfree(chip->desc);
	chip->desc = NULL;
454 455 456
}
EXPORT_SYMBOL_GPL(gpiochip_remove);

457 458 459 460 461 462 463 464 465 466 467
/**
 * gpiochip_find() - iterator for locating a specific gpio_chip
 * @data: data to pass to match function
 * @callback: Callback function to check gpio_chip
 *
 * Similar to bus_find_device.  It returns a reference to a gpio_chip as
 * determined by a user supplied @match callback.  The callback should return
 * 0 if the device doesn't match and non-zero if it does.  If the callback is
 * non-zero, this function will return to the caller and not iterate over any
 * more gpio_chips.
 */
468
struct gpio_chip *gpiochip_find(void *data,
469
				int (*match)(struct gpio_chip *chip,
470
					     void *data))
471
{
472
	struct gpio_chip *chip;
473 474 475
	unsigned long flags;

	spin_lock_irqsave(&gpio_lock, flags);
476 477
	list_for_each_entry(chip, &gpio_chips, list)
		if (match(chip, data))
478
			break;
479 480 481 482

	/* No match? */
	if (&chip->list == &gpio_chips)
		chip = NULL;
483 484 485 486
	spin_unlock_irqrestore(&gpio_lock, flags);

	return chip;
}
Jean Delvare's avatar
Jean Delvare committed
487
EXPORT_SYMBOL_GPL(gpiochip_find);
488

489 490 491 492 493 494 495 496 497 498 499 500
static int gpiochip_match_name(struct gpio_chip *chip, void *data)
{
	const char *name = data;

	return !strcmp(chip->label, name);
}

static struct gpio_chip *find_chip_by_name(const char *name)
{
	return gpiochip_find((void *)name, gpiochip_match_name);
}

501 502 503 504 505 506 507
#ifdef CONFIG_GPIOLIB_IRQCHIP

/*
 * The following is irqchip helper code for gpiochips.
 */

/**
508 509 510
 * gpiochip_set_chained_irqchip() - sets a chained irqchip to a gpiochip
 * @gpiochip: the gpiochip to set the irqchip chain to
 * @irqchip: the irqchip to chain to the gpiochip
511 512 513
 * @parent_irq: the irq number corresponding to the parent IRQ for this
 * chained irqchip
 * @parent_handler: the parent interrupt handler for the accumulated IRQ
514 515
 * coming out of the gpiochip. If the interrupt is nested rather than
 * cascaded, pass NULL in this handler argument
516 517 518 519 520 521
 */
void gpiochip_set_chained_irqchip(struct gpio_chip *gpiochip,
				  struct irq_chip *irqchip,
				  int parent_irq,
				  irq_flow_handler_t parent_handler)
{
522 523 524 525 526
	unsigned int offset;

	if (!gpiochip->irqdomain) {
		chip_err(gpiochip, "called %s before setting up irqchip\n",
			 __func__);
527 528 529
		return;
	}

530 531 532 533 534 535 536 537 538 539 540
	if (parent_handler) {
		if (gpiochip->can_sleep) {
			chip_err(gpiochip,
				 "you cannot have chained interrupts on a "
				 "chip that may sleep\n");
			return;
		}
		/*
		 * The parent irqchip is already using the chip_data for this
		 * irqchip, so our callbacks simply use the handler_data.
		 */
541 542
		irq_set_chained_handler_and_data(parent_irq, parent_handler,
						 gpiochip);
543 544

		gpiochip->irq_parent = parent_irq;
545
	}
546 547 548 549 550

	/* Set the parent IRQ for all affected IRQs */
	for (offset = 0; offset < gpiochip->ngpio; offset++)
		irq_set_parent(irq_find_mapping(gpiochip->irqdomain, offset),
			       parent_irq);
551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569
}
EXPORT_SYMBOL_GPL(gpiochip_set_chained_irqchip);

/**
 * gpiochip_irq_map() - maps an IRQ into a GPIO irqchip
 * @d: the irqdomain used by this irqchip
 * @irq: the global irq number used by this GPIO irqchip irq
 * @hwirq: the local IRQ/GPIO line offset on this gpiochip
 *
 * This function will set up the mapping for a certain IRQ line on a
 * gpiochip by assigning the gpiochip as chip data, and using the irqchip
 * stored inside the gpiochip.
 */
static int gpiochip_irq_map(struct irq_domain *d, unsigned int irq,
			    irq_hw_number_t hwirq)
{
	struct gpio_chip *chip = d->host_data;

	irq_set_chip_data(irq, chip);
570 571 572 573 574
	/*
	 * This lock class tells lockdep that GPIO irqs are in a different
	 * category than their parents, so it won't report false recursion.
	 */
	irq_set_lockdep_class(irq, chip->lock_key);
575
	irq_set_chip_and_handler(irq, chip->irqchip, chip->irq_handler);
576
	/* Chips that can sleep need nested thread handlers */
577
	if (chip->can_sleep && !chip->irq_not_threaded)
578
		irq_set_nested_thread(irq, 1);
579
	irq_set_noprobe(irq);
580

581 582 583 584 585 586
	/*
	 * No set-up of the hardware will happen if IRQ_TYPE_NONE
	 * is passed as default type.
	 */
	if (chip->irq_default_type != IRQ_TYPE_NONE)
		irq_set_irq_type(irq, chip->irq_default_type);
587 588 589 590

	return 0;
}

Linus Walleij's avatar
Linus Walleij committed
591 592
static void gpiochip_irq_unmap(struct irq_domain *d, unsigned int irq)
{
593 594 595 596
	struct gpio_chip *chip = d->host_data;

	if (chip->can_sleep)
		irq_set_nested_thread(irq, 0);
Linus Walleij's avatar
Linus Walleij committed
597 598 599 600
	irq_set_chip_and_handler(irq, NULL, NULL);
	irq_set_chip_data(irq, NULL);
}

601 602
static const struct irq_domain_ops gpiochip_domain_ops = {
	.map	= gpiochip_irq_map,
Linus Walleij's avatar
Linus Walleij committed
603
	.unmap	= gpiochip_irq_unmap,
604 605 606 607 608 609 610 611
	/* Virtually all GPIO irqchips are twocell:ed */
	.xlate	= irq_domain_xlate_twocell,
};

static int gpiochip_irq_reqres(struct irq_data *d)
{
	struct gpio_chip *chip = irq_data_get_irq_chip_data(d);

612 613 614
	if (!try_module_get(chip->owner))
		return -ENODEV;

615
	if (gpiochip_lock_as_irq(chip, d->hwirq)) {
616 617 618
		chip_err(chip,
			"unable to lock HW IRQ %lu for IRQ\n",
			d->hwirq);
619
		module_put(chip->owner);
620 621 622 623 624 625 626 627 628
		return -EINVAL;
	}
	return 0;
}

static void gpiochip_irq_relres(struct irq_data *d)
{
	struct gpio_chip *chip = irq_data_get_irq_chip_data(d);

629
	gpiochip_unlock_as_irq(chip, d->hwirq);
630
	module_put(chip->owner);
631 632 633 634 635 636 637 638 639 640 641 642 643 644 645
}

static int gpiochip_to_irq(struct gpio_chip *chip, unsigned offset)
{
	return irq_find_mapping(chip->irqdomain, offset);
}

/**
 * gpiochip_irqchip_remove() - removes an irqchip added to a gpiochip
 * @gpiochip: the gpiochip to remove the irqchip from
 *
 * This is called only from gpiochip_remove()
 */
static void gpiochip_irqchip_remove(struct gpio_chip *gpiochip)
{
Linus Walleij's avatar
Linus Walleij committed
646 647
	unsigned int offset;

648 649
	acpi_gpiochip_free_interrupts(gpiochip);

650 651 652 653 654
	if (gpiochip->irq_parent) {
		irq_set_chained_handler(gpiochip->irq_parent, NULL);
		irq_set_handler_data(gpiochip->irq_parent, NULL);
	}

Linus Walleij's avatar
Linus Walleij committed
655 656 657
	/* Remove all IRQ mappings and delete the domain */
	if (gpiochip->irqdomain) {
		for (offset = 0; offset < gpiochip->ngpio; offset++)
658 659
			irq_dispose_mapping(
				irq_find_mapping(gpiochip->irqdomain, offset));
660
		irq_domain_remove(gpiochip->irqdomain);
Linus Walleij's avatar
Linus Walleij committed
661
	}
662 663 664 665 666 667 668 669 670 671 672 673 674 675 676

	if (gpiochip->irqchip) {
		gpiochip->irqchip->irq_request_resources = NULL;
		gpiochip->irqchip->irq_release_resources = NULL;
		gpiochip->irqchip = NULL;
	}
}

/**
 * gpiochip_irqchip_add() - adds an irqchip to a gpiochip
 * @gpiochip: the gpiochip to add the irqchip to
 * @irqchip: the irqchip to add to the gpiochip
 * @first_irq: if not dynamically assigned, the base (first) IRQ to
 * allocate gpiochip irqs from
 * @handler: the irq handler to use (often a predefined irq core function)
677 678
 * @type: the default type for IRQs on this irqchip, pass IRQ_TYPE_NONE
 * to have the core avoid setting up any default type in the hardware.
679
 * @lock_key: lockdep class
680 681 682 683 684 685 686 687 688 689 690
 *
 * This function closely associates a certain irqchip with a certain
 * gpiochip, providing an irq domain to translate the local IRQs to
 * global irqs in the gpiolib core, and making sure that the gpiochip
 * is passed as chip data to all related functions. Driver callbacks
 * need to use container_of() to get their local state containers back
 * from the gpiochip passed as chip data. An irqdomain will be stored
 * in the gpiochip that shall be used by the driver to handle IRQ number
 * translation. The gpiochip will need to be initialized and registered
 * before calling this function.
 *
Linus Walleij's avatar
Linus Walleij committed
691 692
 * This function will handle two cell:ed simple IRQs and assumes all
 * the pins on the gpiochip can generate a unique IRQ. Everything else
693 694
 * need to be open coded.
 */
695 696 697 698 699 700
int _gpiochip_irqchip_add(struct gpio_chip *gpiochip,
			  struct irq_chip *irqchip,
			  unsigned int first_irq,
			  irq_flow_handler_t handler,
			  unsigned int type,
			  struct lock_class_key *lock_key)
701 702 703
{
	struct device_node *of_node;
	unsigned int offset;
Linus Walleij's avatar
Linus Walleij committed
704
	unsigned irq_base = 0;
705 706 707 708

	if (!gpiochip || !irqchip)
		return -EINVAL;

709
	if (!gpiochip->parent) {
710 711 712
		pr_err("missing gpiochip .dev parent pointer\n");
		return -EINVAL;
	}
713
	of_node = gpiochip->parent->of_node;
714 715
#ifdef CONFIG_OF_GPIO
	/*
716
	 * If the gpiochip has an assigned OF node this takes precedence
717 718 719 720 721 722 723 724 725
	 * FIXME: get rid of this and use gpiochip->dev->of_node everywhere
	 */
	if (gpiochip->of_node)
		of_node = gpiochip->of_node;
#endif
	gpiochip->irqchip = irqchip;
	gpiochip->irq_handler = handler;
	gpiochip->irq_default_type = type;
	gpiochip->to_irq = gpiochip_to_irq;
726
	gpiochip->lock_key = lock_key;
727 728 729 730 731 732 733
	gpiochip->irqdomain = irq_domain_add_simple(of_node,
					gpiochip->ngpio, first_irq,
					&gpiochip_domain_ops, gpiochip);
	if (!gpiochip->irqdomain) {
		gpiochip->irqchip = NULL;
		return -EINVAL;
	}
734 735 736 737 738 739 740 741 742 743

	/*
	 * It is possible for a driver to override this, but only if the
	 * alternative functions are both implemented.
	 */
	if (!irqchip->irq_request_resources &&
	    !irqchip->irq_release_resources) {
		irqchip->irq_request_resources = gpiochip_irq_reqres;
		irqchip->irq_release_resources = gpiochip_irq_relres;
	}
744 745 746 747 748 749

	/*
	 * Prepare the mapping since the irqchip shall be orthogonal to
	 * any gpiochip calls. If the first_irq was zero, this is
	 * necessary to allocate descriptors for all IRQs.
	 */
Linus Walleij's avatar
Linus Walleij committed
750 751 752 753 754 755 756 757 758
	for (offset = 0; offset < gpiochip->ngpio; offset++) {
		irq_base = irq_create_mapping(gpiochip->irqdomain, offset);
		if (offset == 0)
			/*
			 * Store the base into the gpiochip to be used when
			 * unmapping the irqs.
			 */
			gpiochip->irq_base = irq_base;
	}
759

760 761
	acpi_gpiochip_request_interrupts(gpiochip);

762 763
	return 0;
}
764
EXPORT_SYMBOL_GPL(_gpiochip_irqchip_add);
765 766 767 768 769 770 771

#else /* CONFIG_GPIOLIB_IRQCHIP */

static void gpiochip_irqchip_remove(struct gpio_chip *gpiochip) {}

#endif /* CONFIG_GPIOLIB_IRQCHIP */

772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793
/**
 * gpiochip_generic_request() - request the gpio function for a pin
 * @chip: the gpiochip owning the GPIO
 * @offset: the offset of the GPIO to request for GPIO function
 */
int gpiochip_generic_request(struct gpio_chip *chip, unsigned offset)
{
	return pinctrl_request_gpio(chip->base + offset);
}
EXPORT_SYMBOL_GPL(gpiochip_generic_request);

/**
 * gpiochip_generic_free() - free the gpio function from a pin
 * @chip: the gpiochip to request the gpio function for
 * @offset: the offset of the GPIO to free from GPIO function
 */
void gpiochip_generic_free(struct gpio_chip *chip, unsigned offset)
{
	pinctrl_free_gpio(chip->base + offset);
}
EXPORT_SYMBOL_GPL(gpiochip_generic_free);

794
#ifdef CONFIG_PINCTRL
795

796 797 798
/**
 * gpiochip_add_pingroup_range() - add a range for GPIO <-> pin mapping
 * @chip: the gpiochip to add the range for
799
 * @pctldev: the pin controller to map to
800 801 802 803 804 805 806 807 808 809 810 811
 * @gpio_offset: the start offset in the current gpio_chip number space
 * @pin_group: name of the pin group inside the pin controller
 */
int gpiochip_add_pingroup_range(struct gpio_chip *chip,
			struct pinctrl_dev *pctldev,
			unsigned int gpio_offset, const char *pin_group)
{
	struct gpio_pin_range *pin_range;
	int ret;

	pin_range = kzalloc(sizeof(*pin_range), GFP_KERNEL);
	if (!pin_range) {
812
		chip_err(chip, "failed to allocate pin ranges\n");
813 814 815 816 817 818 819 820 821 822 823 824 825
		return -ENOMEM;
	}

	/* Use local offset as range ID */
	pin_range->range.id = gpio_offset;
	pin_range->range.gc = chip;
	pin_range->range.name = chip->label;
	pin_range->range.base = chip->base + gpio_offset;
	pin_range->pctldev = pctldev;

	ret = pinctrl_get_group_pins(pctldev, pin_group,
					&pin_range->range.pins,
					&pin_range->range.npins);
826 827
	if (ret < 0) {
		kfree(pin_range);
828
		return ret;
829
	}
830 831 832

	pinctrl_add_gpio_range(pctldev, &pin_range->range);

833 834
	chip_dbg(chip, "created GPIO range %d->%d ==> %s PINGRP %s\n",
		 gpio_offset, gpio_offset + pin_range->range.npins - 1,
835 836 837 838 839 840 841 842
		 pinctrl_dev_get_devname(pctldev), pin_group);

	list_add_tail(&pin_range->node, &chip->pin_ranges);

	return 0;
}
EXPORT_SYMBOL_GPL(gpiochip_add_pingroup_range);

843 844 845 846
/**
 * gpiochip_add_pin_range() - add a range for GPIO <-> pin mapping
 * @chip: the gpiochip to add the range for
 * @pinctrl_name: the dev_name() of the pin controller to map to
847 848
 * @gpio_offset: the start offset in the current gpio_chip number space
 * @pin_offset: the start offset in the pin controller number space
849 850 851
 * @npins: the number of pins from the offset of each pin space (GPIO and
 *	pin controller) to accumulate in this range
 */
852
int gpiochip_add_pin_range(struct gpio_chip *chip, const char *pinctl_name,
853
			   unsigned int gpio_offset, unsigned int pin_offset,
854
			   unsigned int npins)
855 856
{
	struct gpio_pin_range *pin_range;
857
	int ret;
858

859
	pin_range = kzalloc(sizeof(*pin_range), GFP_KERNEL);
860
	if (!pin_range) {
861
		chip_err(chip, "failed to allocate pin ranges\n");
862
		return -ENOMEM;
863 864
	}

865
	/* Use local offset as range ID */
866
	pin_range->range.id = gpio_offset;
867
	pin_range->range.gc = chip;
868
	pin_range->range.name = chip->label;
869 870
	pin_range->range.base = chip->base + gpio_offset;
	pin_range->range.pin_base = pin_offset;
871
	pin_range->range.npins = npins;
Linus Walleij's avatar
Linus Walleij committed
872
	pin_range->pctldev = pinctrl_find_and_add_gpio_range(pinctl_name,
873
			&pin_range->range);
874
	if (IS_ERR(pin_range->pctldev)) {
875
		ret = PTR_ERR(pin_range->pctldev);
876
		chip_err(chip, "could not create pin range\n");
877
		kfree(pin_range);
878
		return ret;
879
	}
880 881
	chip_dbg(chip, "created GPIO range %d->%d ==> %s PIN %d->%d\n",
		 gpio_offset, gpio_offset + npins - 1,
882 883
		 pinctl_name,
		 pin_offset, pin_offset + npins - 1);
884 885

	list_add_tail(&pin_range->node, &chip->pin_ranges);
886 887

	return 0;
888
}
889
EXPORT_SYMBOL_GPL(gpiochip_add_pin_range);
890

891 892 893 894
/**
 * gpiochip_remove_pin_ranges() - remove all the GPIO <-> pin mappings
 * @chip: the chip to remove all the mappings for
 */
895 896 897 898 899 900 901 902
void gpiochip_remove_pin_ranges(struct gpio_chip *chip)
{
	struct gpio_pin_range *pin_range, *tmp;

	list_for_each_entry_safe(pin_range, tmp, &chip->pin_ranges, node) {
		list_del(&pin_range->node);
		pinctrl_remove_gpio_range(pin_range->pctldev,
				&pin_range->range);
903
		kfree(pin_range);
904 905
	}
}
906 907 908
EXPORT_SYMBOL_GPL(gpiochip_remove_pin_ranges);

#endif /* CONFIG_PINCTRL */
909

910 911 912 913
/* These "optional" allocation calls help prevent drivers from stomping
 * on each other, and help provide better diagnostics in debugfs.
 * They're called even less than the "set direction" calls.
 */
914
static int __gpiod_request(struct gpio_desc *desc, const char *label)
915
{
916 917
	struct gpio_chip	*chip = desc->chip;
	int			status;
918 919
	unsigned long		flags;

920 921
	spin_lock_irqsave(&gpio_lock, flags);

922
	/* NOTE:  gpio_request() can be called in early boot,
David Brownell's avatar
David Brownell committed
923
	 * before IRQs are enabled, for non-sleeping (SOC) GPIOs.
924 925 926 927 928
	 */

	if (test_and_set_bit(FLAG_REQUESTED, &desc->flags) == 0) {
		desc_set_label(desc, label ? : "?");
		status = 0;
929
	} else {
930
		status = -EBUSY;
931
		goto done;
David Brownell's avatar
David Brownell committed
932 933 934 935 936
	}

	if (chip->request) {
		/* chip->request may sleep */
		spin_unlock_irqrestore(&gpio_lock, flags);
937
		status = chip->request(chip, gpio_chip_hwgpio(desc));
David Brownell's avatar
David Brownell committed
938 939 940 941 942
		spin_lock_irqsave(&gpio_lock, flags);

		if (status < 0) {
			desc_set_label(desc, NULL);
			clear_bit(FLAG_REQUESTED, &desc->flags);
943
			goto done;
David Brownell's avatar
David Brownell committed
944
		}
945
	}
946 947 948
	if (chip->get_direction) {
		/* chip->get_direction may sleep */
		spin_unlock_irqrestore(&gpio_lock, flags);
949
		gpiod_get_direction(desc);
950 951
		spin_lock_irqsave(&gpio_lock, flags);
	}
952
done:
953 954 955 956 957 958 959 960
	if (status < 0) {
		/* Clear flags that might have been set by the caller before
		 * requesting the GPIO.
		 */
		clear_bit(FLAG_ACTIVE_LOW, &desc->flags);
		clear_bit(FLAG_OPEN_DRAIN, &desc->flags);
		clear_bit(FLAG_OPEN_SOURCE, &desc->flags);
	}
961 962 963 964
	spin_unlock_irqrestore(&gpio_lock, flags);
	return status;
}

965
int gpiod_request(struct gpio_desc *desc, const char *label)
966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984
{
	int status = -EPROBE_DEFER;
	struct gpio_chip *chip;

	if (!desc) {
		pr_warn("%s: invalid GPIO\n", __func__);
		return -EINVAL;
	}

	chip = desc->chip;
	if (!chip)
		goto done;

	if (try_module_get(chip->owner)) {
		status = __gpiod_request(desc, label);
		if (status < 0)
			module_put(chip->owner);
	}

985 986
done:
	if (status)
987
		gpiod_dbg(desc, "%s: status %d\n", __func__, status);
988

989 990
	return status;
}
991

992
static bool __gpiod_free(struct gpio_desc *desc)
993
{
994
	bool			ret = false;
995
	unsigned long		flags;
David Brownell's avatar
David Brownell committed
996
	struct gpio_chip	*chip;
997

998 999
	might_sleep();

1000
	gpiod_unexport(desc);
David Brownell's avatar
David Brownell committed
1001

1002 1003
	spin_lock_irqsave(&gpio_lock, flags);

David Brownell's avatar
David Brownell committed
1004 1005 1006 1007
	chip = desc->chip;
	if (chip && test_bit(FLAG_REQUESTED, &desc->flags)) {
		if (chip->free) {
			spin_unlock_irqrestore(&gpio_lock, flags);
1008
			might_sleep_if(chip->can_sleep);
1009
			chip->free(chip, gpio_chip_hwgpio(desc));
David Brownell's avatar
David Brownell committed
1010 1011
			spin_lock_irqsave(&gpio_lock, flags);
		}
1012
		desc_set_label(desc, NULL);
1013
		clear_bit(FLAG_ACTIVE_LOW, &desc->flags);
David Brownell's avatar
David Brownell committed
1014
		clear_bit(FLAG_REQUESTED, &desc->flags);
1015
		clear_bit(FLAG_OPEN_DRAIN, &desc->flags);
1016
		clear_bit(FLAG_OPEN_SOURCE, &desc->flags);
1017
		clear_bit(FLAG_IS_HOGGED, &desc->flags);
1018 1019
		ret = true;
	}
1020 1021

	spin_unlock_irqrestore(&gpio_lock, flags);
1022 1023 1024
	return ret;
}

1025
void gpiod_free(struct gpio_desc *desc)
1026 1027 1028 1029 1030
{
	if (desc && __gpiod_free(desc))
		module_put(desc->chip->owner);
	else
		WARN_ON(extra_checks);
1031
}
1032

1033 1034 1035 1036 1037 1038
/**
 * gpiochip_is_requested - return string iff signal was requested
 * @chip: controller managing the signal
 * @offset: of signal within controller's 0..(ngpio - 1) range
 *
 * Returns NULL if the GPIO is not currently requested, else a string.
1039 1040
 * The string returned is the label passed to gpio_request(); if none has been
 * passed it is a meaningless, non-NULL constant.
1041 1042 1043 1044 1045 1046 1047
 *
 * This function is for use by GPIO controller drivers.  The label can
 * help with diagnostics, and knowing that the signal is used as a GPIO
 * can help avoid accidentally multiplexing it to another controller.
 */
const char *gpiochip_is_requested(struct gpio_chip *chip, unsigned offset)
{
1048
	struct gpio_desc *desc;
1049

1050
	if (offset >= chip->ngpio)
1051
		return NULL;
1052 1053 1054

	desc = &chip->desc[offset];

1055
	if (test_bit(FLAG_REQUESTED, &desc->flags) == 0)
1056
		return NULL;
1057
	return desc->label;
1058 1059 1060
}
EXPORT_SYMBOL_GPL(gpiochip_is_requested);

1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071
/**
 * gpiochip_request_own_desc - Allow GPIO chip to request its own descriptor
 * @desc: GPIO descriptor to request
 * @label: label for the GPIO
 *
 * Function allows GPIO chip drivers to request and use their own GPIO
 * descriptors via gpiolib API. Difference to gpiod_request() is that this
 * function will not increase reference count of the GPIO chip module. This
 * allows the GPIO chip module to be unloaded as needed (we assume that the
 * GPIO chip driver handles freeing the GPIOs it has requested).
 */