gpiolib.c 68 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

183 184 185 186 187 188 189 190 191
/*
 * Add a new chip to the global chips list, keeping the list of chips sorted
 * by base order.
 *
 * 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;
193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219
	struct gpio_chip *_chip;
	int err = 0;

	/* find where to insert our chip */
	list_for_each(pos, &gpio_chips) {
		_chip = list_entry(pos, struct gpio_chip, list);
		/* shall we insert before _chip? */
		if (_chip->base >= chip->base + chip->ngpio)
			break;
	}

	/* are we stepping on the chip right before? */
	if (pos != &gpio_chips && pos->prev != &gpio_chips) {
		_chip = list_entry(pos->prev, struct gpio_chip, list);
		if (_chip->base + _chip->ngpio > chip->base) {
			dev_err(chip->dev,
			       "GPIO integer space overlap, cannot add chip\n");
			err = -EBUSY;
		}
	}

	if (!err)
		list_add_tail(&chip->list, pos);

	return err;
}

220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250
/**
 * 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;
}

251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268
/*
 * Takes the names from gc->names and checks if they are all unique. If they
 * are, they are assigned to their gpio descriptors.
 *
 * Returns -EEXIST if one of the names is already used for a different GPIO.
 */
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]);
269 270 271 272
		if (gpio)
			dev_warn(gc->dev, "Detected name collision for "
				 "GPIO name '%s'\n",
				 gc->names[i]);
273 274 275 276 277 278 279 280 281
	}

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

	return 0;
}

282 283 284
/**
 * gpiochip_add() - register a gpio_chip
 * @chip: the chip to register, with chip->base initialized
285
 * Context: potentially before irqs will work
286 287 288 289
 *
 * 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.
290
 *
David Brownell's avatar
David Brownell committed
291 292 293 294 295
 * 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.
 *
296 297
 * If chip->base is negative, this requests dynamic assignment of
 * a range of valid GPIOs.
298 299 300 301 302 303
 */
int gpiochip_add(struct gpio_chip *chip)
{
	unsigned long	flags;
	int		status = 0;
	unsigned	id;
304
	int		base = chip->base;
305
	struct gpio_desc *descs;
306

307 308 309
	descs = kcalloc(chip->ngpio, sizeof(descs[0]), GFP_KERNEL);
	if (!descs)
		return -ENOMEM;
310 311 312

	spin_lock_irqsave(&gpio_lock, flags);

313 314 315 316
	if (base < 0) {
		base = gpiochip_find_base(chip->ngpio);
		if (base < 0) {
			status = base;
317 318
			spin_unlock_irqrestore(&gpio_lock, flags);
			goto err_free_descs;
319 320 321 322
		}
		chip->base = base;
	}

323
	status = gpiochip_add_to_list(chip);
324 325 326 327
	if (status) {
		spin_unlock_irqrestore(&gpio_lock, flags);
		goto err_free_descs;
	}
328

329 330 331 332 333 334 335 336 337 338 339 340
	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;
341 342
	}

343 344
	chip->desc = descs;

345 346
	spin_unlock_irqrestore(&gpio_lock, flags);

347 348 349 350
#ifdef CONFIG_PINCTRL
	INIT_LIST_HEAD(&chip->pin_ranges);
#endif

351 352 353
	if (!chip->owner && chip->dev && chip->dev->driver)
		chip->owner = chip->dev->driver->owner;

354 355 356 357
	status = gpiochip_set_desc_names(chip);
	if (status)
		goto err_remove_from_list;

358 359 360 361
	status = of_gpiochip_add(chip);
	if (status)
		goto err_remove_chip;

362
	acpi_gpiochip_add(chip);
363

364
	status = gpiochip_sysfs_register(chip);
365 366
	if (status)
		goto err_remove_chip;
367

368
	pr_debug("%s: registered GPIOs %d to %d on device: %s\n", __func__,
369 370 371
		chip->base, chip->base + chip->ngpio - 1,
		chip->label ? : "generic");

372
	return 0;
373

374 375
err_remove_chip:
	acpi_gpiochip_remove(chip);
376
	gpiochip_free_hogs(chip);
377
	of_gpiochip_remove(chip);
378
err_remove_from_list:
379 380
	spin_lock_irqsave(&gpio_lock, flags);
	list_del(&chip->list);
381
	spin_unlock_irqrestore(&gpio_lock, flags);
382
	chip->desc = NULL;
383
err_free_descs:
384 385
	kfree(descs);

386
	/* failures here can mean systems won't boot... */
387
	pr_err("%s: GPIOs %d..%d (%s) failed to register\n", __func__,
388 389
		chip->base, chip->base + chip->ngpio - 1,
		chip->label ? : "generic");
390 391 392 393 394 395 396 397 398 399
	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.
 */
400
void gpiochip_remove(struct gpio_chip *chip)
401
{
Johan Hovold's avatar
Johan Hovold committed
402
	struct gpio_desc *desc;
403 404
	unsigned long	flags;
	unsigned	id;
Johan Hovold's avatar
Johan Hovold committed
405
	bool		requested = false;
406

407
	gpiochip_sysfs_unregister(chip);
408

409 410
	gpiochip_irqchip_remove(chip);

411
	acpi_gpiochip_remove(chip);
412
	gpiochip_remove_pin_ranges(chip);
413
	gpiochip_free_hogs(chip);
414 415
	of_gpiochip_remove(chip);

416
	spin_lock_irqsave(&gpio_lock, flags);
417
	for (id = 0; id < chip->ngpio; id++) {
Johan Hovold's avatar
Johan Hovold committed
418 419 420 421
		desc = &chip->desc[id];
		desc->chip = NULL;
		if (test_bit(FLAG_REQUESTED, &desc->flags))
			requested = true;
422
	}
423
	list_del(&chip->list);
424
	spin_unlock_irqrestore(&gpio_lock, flags);
425

Johan Hovold's avatar
Johan Hovold committed
426 427 428
	if (requested)
		dev_crit(chip->dev, "REMOVING GPIOCHIP WITH GPIOS STILL REQUESTED\n");

429 430
	kfree(chip->desc);
	chip->desc = NULL;
431 432 433
}
EXPORT_SYMBOL_GPL(gpiochip_remove);

434 435 436 437 438 439 440 441 442 443 444
/**
 * 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.
 */
445
struct gpio_chip *gpiochip_find(void *data,
446
				int (*match)(struct gpio_chip *chip,
447
					     void *data))
448
{
449
	struct gpio_chip *chip;
450 451 452
	unsigned long flags;

	spin_lock_irqsave(&gpio_lock, flags);
453 454
	list_for_each_entry(chip, &gpio_chips, list)
		if (match(chip, data))
455
			break;
456 457 458 459

	/* No match? */
	if (&chip->list == &gpio_chips)
		chip = NULL;
460 461 462 463
	spin_unlock_irqrestore(&gpio_lock, flags);

	return chip;
}
Jean Delvare's avatar
Jean Delvare committed
464
EXPORT_SYMBOL_GPL(gpiochip_find);
465

466 467 468 469 470 471 472 473 474 475 476 477
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);
}

478 479 480 481 482 483 484
#ifdef CONFIG_GPIOLIB_IRQCHIP

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

/**
485 486 487
 * 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
488 489 490
 * @parent_irq: the irq number corresponding to the parent IRQ for this
 * chained irqchip
 * @parent_handler: the parent interrupt handler for the accumulated IRQ
491 492
 * coming out of the gpiochip. If the interrupt is nested rather than
 * cascaded, pass NULL in this handler argument
493 494 495 496 497 498
 */
void gpiochip_set_chained_irqchip(struct gpio_chip *gpiochip,
				  struct irq_chip *irqchip,
				  int parent_irq,
				  irq_flow_handler_t parent_handler)
{
499 500 501 502 503
	unsigned int offset;

	if (!gpiochip->irqdomain) {
		chip_err(gpiochip, "called %s before setting up irqchip\n",
			 __func__);
504 505 506
		return;
	}

507 508 509 510 511 512 513 514 515 516 517
	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.
		 */
518 519
		irq_set_chained_handler_and_data(parent_irq, parent_handler,
						 gpiochip);
520 521

		gpiochip->irq_parent = parent_irq;
522
	}
523 524 525 526 527

	/* 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);
528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546
}
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);
547 548 549 550 551
	/*
	 * 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);
552
	irq_set_chip_and_handler(irq, chip->irqchip, chip->irq_handler);
553
	/* Chips that can sleep need nested thread handlers */
554
	if (chip->can_sleep && !chip->irq_not_threaded)
555
		irq_set_nested_thread(irq, 1);
556
	irq_set_noprobe(irq);
557

558 559 560 561 562 563
	/*
	 * 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);
564 565 566 567

	return 0;
}

Linus Walleij's avatar
Linus Walleij committed
568 569
static void gpiochip_irq_unmap(struct irq_domain *d, unsigned int irq)
{
570 571 572 573
	struct gpio_chip *chip = d->host_data;

	if (chip->can_sleep)
		irq_set_nested_thread(irq, 0);
Linus Walleij's avatar
Linus Walleij committed
574 575 576 577
	irq_set_chip_and_handler(irq, NULL, NULL);
	irq_set_chip_data(irq, NULL);
}

578 579
static const struct irq_domain_ops gpiochip_domain_ops = {
	.map	= gpiochip_irq_map,
Linus Walleij's avatar
Linus Walleij committed
580
	.unmap	= gpiochip_irq_unmap,
581 582 583 584 585 586 587 588
	/* 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);

589 590 591
	if (!try_module_get(chip->owner))
		return -ENODEV;

592
	if (gpiochip_lock_as_irq(chip, d->hwirq)) {
593 594 595
		chip_err(chip,
			"unable to lock HW IRQ %lu for IRQ\n",
			d->hwirq);
596
		module_put(chip->owner);
597 598 599 600 601 602 603 604 605
		return -EINVAL;
	}
	return 0;
}

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

606
	gpiochip_unlock_as_irq(chip, d->hwirq);
607
	module_put(chip->owner);
608 609 610 611 612 613 614 615 616 617 618 619 620 621 622
}

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
623 624
	unsigned int offset;

625 626
	acpi_gpiochip_free_interrupts(gpiochip);

627 628 629 630 631
	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
632 633 634
	/* Remove all IRQ mappings and delete the domain */
	if (gpiochip->irqdomain) {
		for (offset = 0; offset < gpiochip->ngpio; offset++)
635 636
			irq_dispose_mapping(
				irq_find_mapping(gpiochip->irqdomain, offset));
637
		irq_domain_remove(gpiochip->irqdomain);
Linus Walleij's avatar
Linus Walleij committed
638
	}
639 640 641 642 643 644 645 646 647 648 649 650 651 652 653

	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)
654 655
 * @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.
656
 * @lock_key: lockdep class
657 658 659 660 661 662 663 664 665 666 667
 *
 * 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
668 669
 * This function will handle two cell:ed simple IRQs and assumes all
 * the pins on the gpiochip can generate a unique IRQ. Everything else
670 671
 * need to be open coded.
 */
672 673 674 675 676 677
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)
678 679 680
{
	struct device_node *of_node;
	unsigned int offset;
Linus Walleij's avatar
Linus Walleij committed
681
	unsigned irq_base = 0;
682 683 684 685 686 687 688 689 690 691 692

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

	if (!gpiochip->dev) {
		pr_err("missing gpiochip .dev parent pointer\n");
		return -EINVAL;
	}
	of_node = gpiochip->dev->of_node;
#ifdef CONFIG_OF_GPIO
	/*
693
	 * If the gpiochip has an assigned OF node this takes precedence
694 695 696 697 698 699 700 701 702
	 * 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;
703
	gpiochip->lock_key = lock_key;
704 705 706 707 708 709 710
	gpiochip->irqdomain = irq_domain_add_simple(of_node,
					gpiochip->ngpio, first_irq,
					&gpiochip_domain_ops, gpiochip);
	if (!gpiochip->irqdomain) {
		gpiochip->irqchip = NULL;
		return -EINVAL;
	}
711 712 713 714 715 716 717 718 719 720

	/*
	 * 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;
	}
721 722 723 724 725 726

	/*
	 * 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
727 728 729 730 731 732 733 734 735
	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;
	}
736

737 738
	acpi_gpiochip_request_interrupts(gpiochip);

739 740
	return 0;
}
741
EXPORT_SYMBOL_GPL(_gpiochip_irqchip_add);
742 743 744 745 746 747 748

#else /* CONFIG_GPIOLIB_IRQCHIP */

static void gpiochip_irqchip_remove(struct gpio_chip *gpiochip) {}

#endif /* CONFIG_GPIOLIB_IRQCHIP */

749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770
/**
 * 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);

771
#ifdef CONFIG_PINCTRL
772

773 774 775
/**
 * gpiochip_add_pingroup_range() - add a range for GPIO <-> pin mapping
 * @chip: the gpiochip to add the range for
776
 * @pctldev: the pin controller to map to
777 778 779 780 781 782 783 784 785 786 787 788
 * @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) {
789
		chip_err(chip, "failed to allocate pin ranges\n");
790 791 792 793 794 795 796 797 798 799 800 801 802
		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);
803 804
	if (ret < 0) {
		kfree(pin_range);
805
		return ret;
806
	}
807 808 809

	pinctrl_add_gpio_range(pctldev, &pin_range->range);

810 811
	chip_dbg(chip, "created GPIO range %d->%d ==> %s PINGRP %s\n",
		 gpio_offset, gpio_offset + pin_range->range.npins - 1,
812 813 814 815 816 817 818 819
		 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);

820 821 822 823
/**
 * 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
824 825
 * @gpio_offset: the start offset in the current gpio_chip number space
 * @pin_offset: the start offset in the pin controller number space
826 827 828
 * @npins: the number of pins from the offset of each pin space (GPIO and
 *	pin controller) to accumulate in this range
 */
829
int gpiochip_add_pin_range(struct gpio_chip *chip, const char *pinctl_name,
830
			   unsigned int gpio_offset, unsigned int pin_offset,
831
			   unsigned int npins)
832 833
{
	struct gpio_pin_range *pin_range;
834
	int ret;
835

836
	pin_range = kzalloc(sizeof(*pin_range), GFP_KERNEL);
837
	if (!pin_range) {
838
		chip_err(chip, "failed to allocate pin ranges\n");
839
		return -ENOMEM;
840 841
	}

842
	/* Use local offset as range ID */
843
	pin_range->range.id = gpio_offset;
844
	pin_range->range.gc = chip;
845
	pin_range->range.name = chip->label;
846 847
	pin_range->range.base = chip->base + gpio_offset;
	pin_range->range.pin_base = pin_offset;
848
	pin_range->range.npins = npins;
Linus Walleij's avatar
Linus Walleij committed
849
	pin_range->pctldev = pinctrl_find_and_add_gpio_range(pinctl_name,
850
			&pin_range->range);
851
	if (IS_ERR(pin_range->pctldev)) {
852
		ret = PTR_ERR(pin_range->pctldev);
853
		chip_err(chip, "could not create pin range\n");
854
		kfree(pin_range);
855
		return ret;
856
	}
857 858
	chip_dbg(chip, "created GPIO range %d->%d ==> %s PIN %d->%d\n",
		 gpio_offset, gpio_offset + npins - 1,
859 860
		 pinctl_name,
		 pin_offset, pin_offset + npins - 1);
861 862

	list_add_tail(&pin_range->node, &chip->pin_ranges);
863 864

	return 0;
865
}
866
EXPORT_SYMBOL_GPL(gpiochip_add_pin_range);
867

868 869 870 871
/**
 * gpiochip_remove_pin_ranges() - remove all the GPIO <-> pin mappings
 * @chip: the chip to remove all the mappings for
 */
872 873 874 875 876 877 878 879
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);
880
		kfree(pin_range);
881 882
	}
}
883 884 885
EXPORT_SYMBOL_GPL(gpiochip_remove_pin_ranges);

#endif /* CONFIG_PINCTRL */
886

887 888 889 890
/* 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.
 */
891
static int __gpiod_request(struct gpio_desc *desc, const char *label)
892
{
893 894
	struct gpio_chip	*chip = desc->chip;
	int			status;
895 896
	unsigned long		flags;

897 898
	spin_lock_irqsave(&gpio_lock, flags);

899
	/* NOTE:  gpio_request() can be called in early boot,
David Brownell's avatar
David Brownell committed
900
	 * before IRQs are enabled, for non-sleeping (SOC) GPIOs.
901 902 903 904 905
	 */

	if (test_and_set_bit(FLAG_REQUESTED, &desc->flags) == 0) {
		desc_set_label(desc, label ? : "?");
		status = 0;
906
	} else {
907
		status = -EBUSY;
908
		goto done;
David Brownell's avatar
David Brownell committed
909 910 911 912 913
	}

	if (chip->request) {
		/* chip->request may sleep */
		spin_unlock_irqrestore(&gpio_lock, flags);
914
		status = chip->request(chip, gpio_chip_hwgpio(desc));
David Brownell's avatar
David Brownell committed
915 916 917 918 919
		spin_lock_irqsave(&gpio_lock, flags);

		if (status < 0) {
			desc_set_label(desc, NULL);
			clear_bit(FLAG_REQUESTED, &desc->flags);
920
			goto done;
David Brownell's avatar
David Brownell committed
921
		}
922
	}
923 924 925
	if (chip->get_direction) {
		/* chip->get_direction may sleep */
		spin_unlock_irqrestore(&gpio_lock, flags);
926
		gpiod_get_direction(desc);
927 928
		spin_lock_irqsave(&gpio_lock, flags);
	}
929
done:
930 931 932 933 934 935 936 937
	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);
	}
938 939 940 941
	spin_unlock_irqrestore(&gpio_lock, flags);
	return status;
}

942
int gpiod_request(struct gpio_desc *desc, const char *label)
943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961
{
	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);
	}

962 963
done:
	if (status)
964
		gpiod_dbg(desc, "%s: status %d\n", __func__, status);
965

966 967
	return status;
}
968

969
static bool __gpiod_free(struct gpio_desc *desc)
970
{
971
	bool			ret = false;
972
	unsigned long		flags;
David Brownell's avatar
David Brownell committed
973
	struct gpio_chip	*chip;
974

975 976
	might_sleep();

977
	gpiod_unexport(desc);
David Brownell's avatar
David Brownell committed
978

979 980
	spin_lock_irqsave(&gpio_lock, flags);

David Brownell's avatar
David Brownell committed
981 982 983 984
	chip = desc->chip;
	if (chip && test_bit(FLAG_REQUESTED, &desc->flags)) {
		if (chip->free) {
			spin_unlock_irqrestore(&gpio_lock, flags);
985
			might_sleep_if(chip->can_sleep);
986
			chip->free(chip, gpio_chip_hwgpio(desc));
David Brownell's avatar
David Brownell committed
987 988
			spin_lock_irqsave(&gpio_lock, flags);
		}
989
		desc_set_label(desc, NULL);
990
		clear_bit(FLAG_ACTIVE_LOW, &desc->flags);
David Brownell's avatar
David Brownell committed
991
		clear_bit(FLAG_REQUESTED, &desc->flags);
992
		clear_bit(FLAG_OPEN_DRAIN, &desc->flags);
993
		clear_bit(FLAG_OPEN_SOURCE, &desc->flags);
994
		clear_bit(FLAG_IS_HOGGED, &desc->flags);
995 996
		ret = true;
	}
997 998

	spin_unlock_irqrestore(&gpio_lock, flags);
999 1000 1001
	return ret;
}

1002
void gpiod_free(struct gpio_desc *desc)
1003 1004 1005 1006 1007
{
	if (desc && __gpiod_free(desc))
		module_put(desc->chip->owner);
	else
		WARN_ON(extra_checks);
1008
}
1009

1010 1011 1012 1013 1014 1015
/**
 * 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.
1016 1017
 * The string returned is the label passed to gpio_request(); if none has been
 * passed it is a meaningless, non-NULL constant.
1018 1019 1020 1021 1022 1023 1024
 *
 * 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)
{
1025
	struct gpio_desc *desc;
1026

1027
	if (offset >= chip->ngpio)
1028
		return NULL;
1029 1030 1031

	desc = &chip->desc[offset];

1032
	if (test_bit(FLAG_REQUESTED, &desc->flags) == 0)
1033
		return NULL;
1034
	return desc->label;
1035 1036 1037
}
EXPORT_SYMBOL_GPL(gpiochip_is_requested);

1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048
/**
 * 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).
 */
1049 1050
struct gpio_desc *gpiochip_request_own_desc(struct gpio_chip *chip, u16 hwnum,
					    const char *label)
1051
{
1052 1053
	struct gpio_desc *desc = gpiochip_get_desc(chip, hwnum);
	int err;
1054

1055 1056 1057 1058 1059 1060 1061 1062
	if (IS_ERR(desc)) {
		chip_err(chip, "failed to get GPIO descriptor\n");
		return desc;
	}

	err = __gpiod_request(desc, label);
	if (err < 0)
		return ERR_PTR(err);
1063

1064
	return desc;
1065
}
1066
EXPORT_SYMBOL_GPL(gpiochip_request_own_desc);
1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079

/**
 * gpiochip_free_own_desc - Free GPIO requested by the chip driver
 * @desc: GPIO descriptor to free
 *
 * Function frees the given GPIO requested previously with
 * gpiochip_request_own_desc().
 */
void gpiochip_free_own_desc(struct gpio_desc *desc)
{
	if (desc)
		__gpiod_free(desc);
}
1080
EXPORT_SYMBOL_GPL(gpiochip_free_own_desc);
1081 1082 1083 1084 1085 1086 1087 1088 1089 1090

/* Drivers MUST set GPIO direction before making get/set calls.  In
 * some cases this is done in early boot, before IRQs are enabled.
 *
 * As a rule these aren't called more than once (except for drivers
 * using the open-drain emulation idiom) so these are natural places
 * to accumulate extra debugging checks.  Note that we can't (yet)
 * rely on gpio_request() having been called beforehand.
 */

1091 1092 1093 1094 1095 1096 1097 1098 1099 1100
/**
 * gpiod_direction_input - set the GPIO direction to input
 * @desc:	GPIO to set to input
 *
 * Set the direction of the passed GPIO to input, such as gpiod_get_value() can
 * be called safely on it.
 *
 * Return 0 in case of success, else an error code.
 */
int gpiod_direction_input(struct gpio_desc *desc)
1101 1102 1103 1104
{
	struct gpio_chip	*chip;
	int			status = -EINVAL;

1105
	if (!desc || !desc->chip) {
1106 1107 1108 1109
		pr_warn("%s: invalid GPIO\n", __func__);
		return -EINVAL;
	}

1110 1111
	chip = desc