gpiolib.c 94.3 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
#include <linux/idr.h>
20 21 22
#include <linux/cdev.h>
#include <linux/fs.h>
#include <linux/uaccess.h>
23
#include <linux/compat.h>
24
#include <linux/anon_inodes.h>
25 26 27
#include <linux/kfifo.h>
#include <linux/poll.h>
#include <linux/timekeeping.h>
28
#include <uapi/linux/gpio.h>
29

30 31
#include "gpiolib.h"

32 33
#define CREATE_TRACE_POINTS
#include <trace/events/gpio.h>
34

35
/* Implementation infrastructure for GPIO interfaces.
36
 *
37 38 39
 * 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.
40 41 42 43 44 45 46 47 48 49 50 51 52 53 54
 */


/* 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

55 56
/* Device and char device-related information */
static DEFINE_IDA(gpio_ida);
57 58 59 60 61
static dev_t gpio_devt;
#define GPIO_DEV_MAX 256 /* 256 GPIO chip devices supported */
static struct bus_type gpio_bus_type = {
	.name = "gpio",
};
62

63 64 65 66
/* 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.
 */
67
DEFINE_SPINLOCK(gpio_lock);
68

69 70
static DEFINE_MUTEX(gpio_lookup_lock);
static LIST_HEAD(gpio_lookup_list);
71
LIST_HEAD(gpio_devices);
72 73 74 75

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

76
static bool gpiolib_initialized;
77

78 79 80 81 82
static inline void desc_set_label(struct gpio_desc *d, const char *label)
{
	d->label = label;
}

83 84 85
/**
 * Convert a GPIO number to its descriptor
 */
86
struct gpio_desc *gpio_to_desc(unsigned gpio)
87
{
88
	struct gpio_device *gdev;
89 90 91 92
	unsigned long flags;

	spin_lock_irqsave(&gpio_lock, flags);

93
	list_for_each_entry(gdev, &gpio_devices, list) {
94 95
		if (gdev->base <= gpio &&
		    gdev->base + gdev->ngpio > gpio) {
96
			spin_unlock_irqrestore(&gpio_lock, flags);
97
			return &gdev->descs[gpio - gdev->base];
98 99 100 101 102
		}
	}

	spin_unlock_irqrestore(&gpio_lock, flags);

103 104 105
	if (!gpio_is_valid(gpio))
		WARN(1, "invalid GPIO %d\n", gpio);

106
	return NULL;
107
}
108
EXPORT_SYMBOL_GPL(gpio_to_desc);
109

110
/**
111
 * Get the GPIO descriptor corresponding to the given hw number for this chip.
112
 */
113 114
struct gpio_desc *gpiochip_get_desc(struct gpio_chip *chip,
				    u16 hwnum)
115
{
116 117 118
	struct gpio_device *gdev = chip->gpiodev;

	if (hwnum >= gdev->ngpio)
119
		return ERR_PTR(-EINVAL);
120

121
	return &gdev->descs[hwnum];
122
}
123 124 125 126 127 128

/**
 * 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
 */
129
int desc_to_gpio(const struct gpio_desc *desc)
130
{
131
	return desc->gdev->base + (desc - &desc->gdev->descs[0]);
132
}
133
EXPORT_SYMBOL_GPL(desc_to_gpio);
134 135


136 137 138 139 140
/**
 * 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)
141
{
142 143 144
	if (!desc || !desc->gdev || !desc->gdev->chip)
		return NULL;
	return desc->gdev->chip;
145
}
146
EXPORT_SYMBOL_GPL(gpiod_to_chip);
147

148 149 150
/* dynamic allocation of GPIOs, e.g. on a hotplugged device */
static int gpiochip_find_base(int ngpio)
{
151
	struct gpio_device *gdev;
152
	int base = ARCH_NR_GPIOS - ngpio;
153

154
	list_for_each_entry_reverse(gdev, &gpio_devices, list) {
155
		/* found a free space? */
156
		if (gdev->base + gdev->ngpio <= base)
157 158 159
			break;
		else
			/* nope, check the space right before the chip */
160
			base = gdev->base - ngpio;
161 162
	}

163
	if (gpio_is_valid(base)) {
164
		pr_debug("%s: found new base at %d\n", __func__, base);
165 166 167 168
		return base;
	} else {
		pr_err("%s: cannot find free range\n", __func__);
		return -ENOSPC;
Anton Vorontsov's avatar
Anton Vorontsov committed
169 170 171
	}
}

172 173 174 175 176 177 178 179
/**
 * 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.
 */
180
int gpiod_get_direction(struct gpio_desc *desc)
181 182
{
	struct gpio_chip	*chip;
183
	unsigned		offset;
184 185
	int			status = -EINVAL;

186 187
	chip = gpiod_to_chip(desc);
	offset = gpio_chip_hwgpio(desc);
188 189 190 191

	if (!chip->get_direction)
		return status;

192
	status = chip->get_direction(chip, offset);
193 194 195
	if (status > 0) {
		/* GPIOF_DIR_IN, or other positive */
		status = 1;
196
		clear_bit(FLAG_IS_OUT, &desc->flags);
197 198 199
	}
	if (status == 0) {
		/* GPIOF_DIR_OUT */
200
		set_bit(FLAG_IS_OUT, &desc->flags);
201 202 203
	}
	return status;
}
204
EXPORT_SYMBOL_GPL(gpiod_get_direction);
205

206 207
/*
 * Add a new chip to the global chips list, keeping the list of chips sorted
208
 * by range(means [base, base + ngpio - 1]) order.
209 210 211 212
 *
 * Return -EBUSY if the new chip overlaps with some other chip's integer
 * space.
 */
213
static int gpiodev_add_to_list(struct gpio_device *gdev)
214
{
215
	struct gpio_device *prev, *next;
216

217
	if (list_empty(&gpio_devices)) {
218
		/* initial entry in list */
219
		list_add_tail(&gdev->list, &gpio_devices);
220
		return 0;
221 222
	}

223 224 225 226 227
	next = list_entry(gpio_devices.next, struct gpio_device, list);
	if (gdev->base + gdev->ngpio <= next->base) {
		/* add before first entry */
		list_add(&gdev->list, &gpio_devices);
		return 0;
228 229
	}

230 231 232 233
	prev = list_entry(gpio_devices.prev, struct gpio_device, list);
	if (prev->base + prev->ngpio <= gdev->base) {
		/* add behind last entry */
		list_add_tail(&gdev->list, &gpio_devices);
234
		return 0;
235 236
	}

237 238 239 240
	list_for_each_entry_safe(prev, next, &gpio_devices, list) {
		/* at the end of the list */
		if (&next->list == &gpio_devices)
			break;
241

242 243 244 245 246 247 248 249 250 251
		/* add between prev and next */
		if (prev->base + prev->ngpio <= gdev->base
				&& gdev->base + gdev->ngpio <= next->base) {
			list_add(&gdev->list, &prev->list);
			return 0;
		}
	}

	dev_err(&gdev->dev, "GPIO integer space overlap, cannot add chip\n");
	return -EBUSY;
252 253
}

254 255 256 257 258
/**
 * Convert a GPIO name to its descriptor
 */
static struct gpio_desc *gpio_name_to_desc(const char * const name)
{
259
	struct gpio_device *gdev;
260 261 262 263
	unsigned long flags;

	spin_lock_irqsave(&gpio_lock, flags);

264
	list_for_each_entry(gdev, &gpio_devices, list) {
265 266
		int i;

267 268
		for (i = 0; i != gdev->ngpio; ++i) {
			struct gpio_desc *desc = &gdev->descs[i];
269

270
			if (!desc->name || !name)
271 272
				continue;

273
			if (!strcmp(desc->name, name)) {
274
				spin_unlock_irqrestore(&gpio_lock, flags);
275
				return desc;
276 277 278 279 280 281 282 283 284
			}
		}
	}

	spin_unlock_irqrestore(&gpio_lock, flags);

	return NULL;
}

285 286 287 288
/*
 * Takes the names from gc->names and checks if they are all unique. If they
 * are, they are assigned to their gpio descriptors.
 *
289
 * Warning if one of the names is already used for a different GPIO.
290 291 292
 */
static int gpiochip_set_desc_names(struct gpio_chip *gc)
{
293
	struct gpio_device *gdev = gc->gpiodev;
294 295 296 297 298 299 300 301 302 303
	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]);
304
		if (gpio)
305
			dev_warn(&gdev->dev,
306
				 "Detected name collision for GPIO name '%s'\n",
307
				 gc->names[i]);
308 309 310 311
	}

	/* Then add all names to the GPIO descriptors */
	for (i = 0; i != gc->ngpio; ++i)
312
		gdev->descs[i].name = gc->names[i];
313 314 315 316

	return 0;
}

317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476
/*
 * GPIO line handle management
 */

/**
 * struct linehandle_state - contains the state of a userspace handle
 * @gdev: the GPIO device the handle pertains to
 * @label: consumer label used to tag descriptors
 * @descs: the GPIO descriptors held by this handle
 * @numdescs: the number of descriptors held in the descs array
 */
struct linehandle_state {
	struct gpio_device *gdev;
	const char *label;
	struct gpio_desc *descs[GPIOHANDLES_MAX];
	u32 numdescs;
};

static long linehandle_ioctl(struct file *filep, unsigned int cmd,
			     unsigned long arg)
{
	struct linehandle_state *lh = filep->private_data;
	void __user *ip = (void __user *)arg;
	struct gpiohandle_data ghd;
	int i;

	if (cmd == GPIOHANDLE_GET_LINE_VALUES_IOCTL) {
		int val;

		/* TODO: check if descriptors are really input */
		for (i = 0; i < lh->numdescs; i++) {
			val = gpiod_get_value_cansleep(lh->descs[i]);
			if (val < 0)
				return val;
			ghd.values[i] = val;
		}

		if (copy_to_user(ip, &ghd, sizeof(ghd)))
			return -EFAULT;

		return 0;
	} else if (cmd == GPIOHANDLE_SET_LINE_VALUES_IOCTL) {
		int vals[GPIOHANDLES_MAX];

		/* TODO: check if descriptors are really output */
		if (copy_from_user(&ghd, ip, sizeof(ghd)))
			return -EFAULT;

		/* Clamp all values to [0,1] */
		for (i = 0; i < lh->numdescs; i++)
			vals[i] = !!ghd.values[i];

		/* Reuse the array setting function */
		gpiod_set_array_value_complex(false,
					      true,
					      lh->numdescs,
					      lh->descs,
					      vals);
		return 0;
	}
	return -EINVAL;
}

#ifdef CONFIG_COMPAT
static long linehandle_ioctl_compat(struct file *filep, unsigned int cmd,
			     unsigned long arg)
{
	return linehandle_ioctl(filep, cmd, (unsigned long)compat_ptr(arg));
}
#endif

static int linehandle_release(struct inode *inode, struct file *filep)
{
	struct linehandle_state *lh = filep->private_data;
	struct gpio_device *gdev = lh->gdev;
	int i;

	for (i = 0; i < lh->numdescs; i++)
		gpiod_free(lh->descs[i]);
	kfree(lh->label);
	kfree(lh);
	put_device(&gdev->dev);
	return 0;
}

static const struct file_operations linehandle_fileops = {
	.release = linehandle_release,
	.owner = THIS_MODULE,
	.llseek = noop_llseek,
	.unlocked_ioctl = linehandle_ioctl,
#ifdef CONFIG_COMPAT
	.compat_ioctl = linehandle_ioctl_compat,
#endif
};

static int linehandle_create(struct gpio_device *gdev, void __user *ip)
{
	struct gpiohandle_request handlereq;
	struct linehandle_state *lh;
	int fd, i, ret;

	if (copy_from_user(&handlereq, ip, sizeof(handlereq)))
		return -EFAULT;
	if ((handlereq.lines == 0) || (handlereq.lines > GPIOHANDLES_MAX))
		return -EINVAL;

	lh = kzalloc(sizeof(*lh), GFP_KERNEL);
	if (!lh)
		return -ENOMEM;
	lh->gdev = gdev;
	get_device(&gdev->dev);

	/* Make sure this is terminated */
	handlereq.consumer_label[sizeof(handlereq.consumer_label)-1] = '\0';
	if (strlen(handlereq.consumer_label)) {
		lh->label = kstrdup(handlereq.consumer_label,
				    GFP_KERNEL);
		if (!lh->label) {
			ret = -ENOMEM;
			goto out_free_lh;
		}
	}

	/* Request each GPIO */
	for (i = 0; i < handlereq.lines; i++) {
		u32 offset = handlereq.lineoffsets[i];
		u32 lflags = handlereq.flags;
		struct gpio_desc *desc;

		desc = &gdev->descs[offset];
		ret = gpiod_request(desc, lh->label);
		if (ret)
			goto out_free_descs;
		lh->descs[i] = desc;

		if (lflags & GPIOHANDLE_REQUEST_ACTIVE_LOW)
			set_bit(FLAG_ACTIVE_LOW, &desc->flags);
		if (lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN)
			set_bit(FLAG_OPEN_DRAIN, &desc->flags);
		if (lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE)
			set_bit(FLAG_OPEN_SOURCE, &desc->flags);

		/*
		 * Lines have to be requested explicitly for input
		 * or output, else the line will be treated "as is".
		 */
		if (lflags & GPIOHANDLE_REQUEST_OUTPUT) {
			int val = !!handlereq.default_values[i];

			ret = gpiod_direction_output(desc, val);
			if (ret)
				goto out_free_descs;
		} else if (lflags & GPIOHANDLE_REQUEST_INPUT) {
			ret = gpiod_direction_input(desc);
			if (ret)
				goto out_free_descs;
		}
		dev_dbg(&gdev->dev, "registered chardev handle for line %d\n",
			offset);
	}
477 478
	/* Let i point at the last handle */
	i--;
479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508
	lh->numdescs = handlereq.lines;

	fd = anon_inode_getfd("gpio-linehandle",
			      &linehandle_fileops,
			      lh,
			      O_RDONLY | O_CLOEXEC);
	if (fd < 0) {
		ret = fd;
		goto out_free_descs;
	}

	handlereq.fd = fd;
	if (copy_to_user(ip, &handlereq, sizeof(handlereq)))
		return -EFAULT;

	dev_dbg(&gdev->dev, "registered chardev handle for %d lines\n",
		lh->numdescs);

	return 0;

out_free_descs:
	for (; i >= 0; i--)
		gpiod_free(lh->descs[i]);
	kfree(lh->label);
out_free_lh:
	kfree(lh);
	put_device(&gdev->dev);
	return ret;
}

509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678
/*
 * GPIO line event management
 */

/**
 * struct lineevent_state - contains the state of a userspace event
 * @gdev: the GPIO device the event pertains to
 * @label: consumer label used to tag descriptors
 * @desc: the GPIO descriptor held by this event
 * @eflags: the event flags this line was requested with
 * @irq: the interrupt that trigger in response to events on this GPIO
 * @wait: wait queue that handles blocking reads of events
 * @events: KFIFO for the GPIO events
 * @read_lock: mutex lock to protect reads from colliding with adding
 * new events to the FIFO
 */
struct lineevent_state {
	struct gpio_device *gdev;
	const char *label;
	struct gpio_desc *desc;
	u32 eflags;
	int irq;
	wait_queue_head_t wait;
	DECLARE_KFIFO(events, struct gpioevent_data, 16);
	struct mutex read_lock;
};

static unsigned int lineevent_poll(struct file *filep,
				   struct poll_table_struct *wait)
{
	struct lineevent_state *le = filep->private_data;
	unsigned int events = 0;

	poll_wait(filep, &le->wait, wait);

	if (!kfifo_is_empty(&le->events))
		events = POLLIN | POLLRDNORM;

	return events;
}


static ssize_t lineevent_read(struct file *filep,
			      char __user *buf,
			      size_t count,
			      loff_t *f_ps)
{
	struct lineevent_state *le = filep->private_data;
	unsigned int copied;
	int ret;

	if (count < sizeof(struct gpioevent_data))
		return -EINVAL;

	do {
		if (kfifo_is_empty(&le->events)) {
			if (filep->f_flags & O_NONBLOCK)
				return -EAGAIN;

			ret = wait_event_interruptible(le->wait,
					!kfifo_is_empty(&le->events));
			if (ret)
				return ret;
		}

		if (mutex_lock_interruptible(&le->read_lock))
			return -ERESTARTSYS;
		ret = kfifo_to_user(&le->events, buf, count, &copied);
		mutex_unlock(&le->read_lock);

		if (ret)
			return ret;

		/*
		 * If we couldn't read anything from the fifo (a different
		 * thread might have been faster) we either return -EAGAIN if
		 * the file descriptor is non-blocking, otherwise we go back to
		 * sleep and wait for more data to arrive.
		 */
		if (copied == 0 && (filep->f_flags & O_NONBLOCK))
			return -EAGAIN;

	} while (copied == 0);

	return copied;
}

static int lineevent_release(struct inode *inode, struct file *filep)
{
	struct lineevent_state *le = filep->private_data;
	struct gpio_device *gdev = le->gdev;

	free_irq(le->irq, le);
	gpiod_free(le->desc);
	kfree(le->label);
	kfree(le);
	put_device(&gdev->dev);
	return 0;
}

static long lineevent_ioctl(struct file *filep, unsigned int cmd,
			    unsigned long arg)
{
	struct lineevent_state *le = filep->private_data;
	void __user *ip = (void __user *)arg;
	struct gpiohandle_data ghd;

	/*
	 * We can get the value for an event line but not set it,
	 * because it is input by definition.
	 */
	if (cmd == GPIOHANDLE_GET_LINE_VALUES_IOCTL) {
		int val;

		val = gpiod_get_value_cansleep(le->desc);
		if (val < 0)
			return val;
		ghd.values[0] = val;

		if (copy_to_user(ip, &ghd, sizeof(ghd)))
			return -EFAULT;

		return 0;
	}
	return -EINVAL;
}

#ifdef CONFIG_COMPAT
static long lineevent_ioctl_compat(struct file *filep, unsigned int cmd,
				   unsigned long arg)
{
	return lineevent_ioctl(filep, cmd, (unsigned long)compat_ptr(arg));
}
#endif

static const struct file_operations lineevent_fileops = {
	.release = lineevent_release,
	.read = lineevent_read,
	.poll = lineevent_poll,
	.owner = THIS_MODULE,
	.llseek = noop_llseek,
	.unlocked_ioctl = lineevent_ioctl,
#ifdef CONFIG_COMPAT
	.compat_ioctl = lineevent_ioctl_compat,
#endif
};

irqreturn_t lineevent_irq_thread(int irq, void *p)
{
	struct lineevent_state *le = p;
	struct gpioevent_data ge;
	int ret;

	ge.timestamp = ktime_get_real_ns();

	if (le->eflags & GPIOEVENT_REQUEST_BOTH_EDGES) {
		int level = gpiod_get_value_cansleep(le->desc);

		if (level)
			/* Emit low-to-high event */
			ge.id = GPIOEVENT_EVENT_RISING_EDGE;
		else
			/* Emit high-to-low event */
			ge.id = GPIOEVENT_EVENT_FALLING_EDGE;
	} else if (le->eflags & GPIOEVENT_REQUEST_RISING_EDGE) {
		/* Emit low-to-high event */
		ge.id = GPIOEVENT_EVENT_RISING_EDGE;
	} else if (le->eflags & GPIOEVENT_REQUEST_FALLING_EDGE) {
		/* Emit high-to-low event */
		ge.id = GPIOEVENT_EVENT_FALLING_EDGE;
679 680
	} else {
		return IRQ_NONE;
681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803
	}

	ret = kfifo_put(&le->events, ge);
	if (ret != 0)
		wake_up_poll(&le->wait, POLLIN);

	return IRQ_HANDLED;
}

static int lineevent_create(struct gpio_device *gdev, void __user *ip)
{
	struct gpioevent_request eventreq;
	struct lineevent_state *le;
	struct gpio_desc *desc;
	u32 offset;
	u32 lflags;
	u32 eflags;
	int fd;
	int ret;
	int irqflags = 0;

	if (copy_from_user(&eventreq, ip, sizeof(eventreq)))
		return -EFAULT;

	le = kzalloc(sizeof(*le), GFP_KERNEL);
	if (!le)
		return -ENOMEM;
	le->gdev = gdev;
	get_device(&gdev->dev);

	/* Make sure this is terminated */
	eventreq.consumer_label[sizeof(eventreq.consumer_label)-1] = '\0';
	if (strlen(eventreq.consumer_label)) {
		le->label = kstrdup(eventreq.consumer_label,
				    GFP_KERNEL);
		if (!le->label) {
			ret = -ENOMEM;
			goto out_free_le;
		}
	}

	offset = eventreq.lineoffset;
	lflags = eventreq.handleflags;
	eflags = eventreq.eventflags;

	/* This is just wrong: we don't look for events on output lines */
	if (lflags & GPIOHANDLE_REQUEST_OUTPUT) {
		ret = -EINVAL;
		goto out_free_label;
	}

	desc = &gdev->descs[offset];
	ret = gpiod_request(desc, le->label);
	if (ret)
		goto out_free_desc;
	le->desc = desc;
	le->eflags = eflags;

	if (lflags & GPIOHANDLE_REQUEST_ACTIVE_LOW)
		set_bit(FLAG_ACTIVE_LOW, &desc->flags);
	if (lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN)
		set_bit(FLAG_OPEN_DRAIN, &desc->flags);
	if (lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE)
		set_bit(FLAG_OPEN_SOURCE, &desc->flags);

	ret = gpiod_direction_input(desc);
	if (ret)
		goto out_free_desc;

	le->irq = gpiod_to_irq(desc);
	if (le->irq <= 0) {
		ret = -ENODEV;
		goto out_free_desc;
	}

	if (eflags & GPIOEVENT_REQUEST_RISING_EDGE)
		irqflags |= IRQF_TRIGGER_RISING;
	if (eflags & GPIOEVENT_REQUEST_FALLING_EDGE)
		irqflags |= IRQF_TRIGGER_FALLING;
	irqflags |= IRQF_ONESHOT;
	irqflags |= IRQF_SHARED;

	INIT_KFIFO(le->events);
	init_waitqueue_head(&le->wait);
	mutex_init(&le->read_lock);

	/* Request a thread to read the events */
	ret = request_threaded_irq(le->irq,
			NULL,
			lineevent_irq_thread,
			irqflags,
			le->label,
			le);
	if (ret)
		goto out_free_desc;

	fd = anon_inode_getfd("gpio-event",
			      &lineevent_fileops,
			      le,
			      O_RDONLY | O_CLOEXEC);
	if (fd < 0) {
		ret = fd;
		goto out_free_irq;
	}

	eventreq.fd = fd;
	if (copy_to_user(ip, &eventreq, sizeof(eventreq)))
		return -EFAULT;

	return 0;

out_free_irq:
	free_irq(le->irq, le);
out_free_desc:
	gpiod_free(le->desc);
out_free_label:
	kfree(le->label);
out_free_le:
	kfree(le);
	put_device(&gdev->dev);
	return ret;
}

804 805 806 807 808 809 810
/**
 * gpio_ioctl() - ioctl handler for the GPIO chardev
 */
static long gpio_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
{
	struct gpio_device *gdev = filp->private_data;
	struct gpio_chip *chip = gdev->chip;
811
	void __user *ip = (void __user *)arg;
812 813 814 815 816

	/* We fail any subsequent ioctl():s when the chip is gone */
	if (!chip)
		return -ENODEV;

817
	/* Fill in the struct and pass to userspace */
818
	if (cmd == GPIO_GET_CHIPINFO_IOCTL) {
819 820
		struct gpiochip_info chipinfo;

821 822 823
		strncpy(chipinfo.name, dev_name(&gdev->dev),
			sizeof(chipinfo.name));
		chipinfo.name[sizeof(chipinfo.name)-1] = '\0';
824 825 826
		strncpy(chipinfo.label, gdev->label,
			sizeof(chipinfo.label));
		chipinfo.label[sizeof(chipinfo.label)-1] = '\0';
827
		chipinfo.lines = gdev->ngpio;
828 829 830
		if (copy_to_user(ip, &chipinfo, sizeof(chipinfo)))
			return -EFAULT;
		return 0;
831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848
	} else if (cmd == GPIO_GET_LINEINFO_IOCTL) {
		struct gpioline_info lineinfo;
		struct gpio_desc *desc;

		if (copy_from_user(&lineinfo, ip, sizeof(lineinfo)))
			return -EFAULT;
		if (lineinfo.line_offset > gdev->ngpio)
			return -EINVAL;

		desc = &gdev->descs[lineinfo.line_offset];
		if (desc->name) {
			strncpy(lineinfo.name, desc->name,
				sizeof(lineinfo.name));
			lineinfo.name[sizeof(lineinfo.name)-1] = '\0';
		} else {
			lineinfo.name[0] = '\0';
		}
		if (desc->label) {
849 850 851
			strncpy(lineinfo.consumer, desc->label,
				sizeof(lineinfo.consumer));
			lineinfo.consumer[sizeof(lineinfo.consumer)-1] = '\0';
852
		} else {
853
			lineinfo.consumer[0] = '\0';
854 855 856 857 858 859 860
		}

		/*
		 * Userspace only need to know that the kernel is using
		 * this GPIO so it can't use it.
		 */
		lineinfo.flags = 0;
861 862 863 864 865
		if (test_bit(FLAG_REQUESTED, &desc->flags) ||
		    test_bit(FLAG_IS_HOGGED, &desc->flags) ||
		    test_bit(FLAG_USED_AS_IRQ, &desc->flags) ||
		    test_bit(FLAG_EXPORT, &desc->flags) ||
		    test_bit(FLAG_SYSFS, &desc->flags))
866
			lineinfo.flags |= GPIOLINE_FLAG_KERNEL;
867
		if (test_bit(FLAG_IS_OUT, &desc->flags))
868
			lineinfo.flags |= GPIOLINE_FLAG_IS_OUT;
869
		if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
870
			lineinfo.flags |= GPIOLINE_FLAG_ACTIVE_LOW;
871
		if (test_bit(FLAG_OPEN_DRAIN, &desc->flags))
872
			lineinfo.flags |= GPIOLINE_FLAG_OPEN_DRAIN;
873
		if (test_bit(FLAG_OPEN_SOURCE, &desc->flags))
874 875 876 877 878
			lineinfo.flags |= GPIOLINE_FLAG_OPEN_SOURCE;

		if (copy_to_user(ip, &lineinfo, sizeof(lineinfo)))
			return -EFAULT;
		return 0;
879 880
	} else if (cmd == GPIO_GET_LINEHANDLE_IOCTL) {
		return linehandle_create(gdev, ip);
881 882
	} else if (cmd == GPIO_GET_LINEEVENT_IOCTL) {
		return lineevent_create(gdev, ip);
883 884 885 886
	}
	return -EINVAL;
}

887 888 889 890 891 892 893 894
#ifdef CONFIG_COMPAT
static long gpio_ioctl_compat(struct file *filp, unsigned int cmd,
			      unsigned long arg)
{
	return gpio_ioctl(filp, cmd, (unsigned long)compat_ptr(arg));
}
#endif

895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937
/**
 * gpio_chrdev_open() - open the chardev for ioctl operations
 * @inode: inode for this chardev
 * @filp: file struct for storing private data
 * Returns 0 on success
 */
static int gpio_chrdev_open(struct inode *inode, struct file *filp)
{
	struct gpio_device *gdev = container_of(inode->i_cdev,
					      struct gpio_device, chrdev);

	/* Fail on open if the backing gpiochip is gone */
	if (!gdev || !gdev->chip)
		return -ENODEV;
	get_device(&gdev->dev);
	filp->private_data = gdev;
	return 0;
}

/**
 * gpio_chrdev_release() - close chardev after ioctl operations
 * @inode: inode for this chardev
 * @filp: file struct for storing private data
 * Returns 0 on success
 */
static int gpio_chrdev_release(struct inode *inode, struct file *filp)
{
	struct gpio_device *gdev = container_of(inode->i_cdev,
					      struct gpio_device, chrdev);

	if (!gdev)
		return -ENODEV;
	put_device(&gdev->dev);
	return 0;
}


static const struct file_operations gpio_fileops = {
	.release = gpio_chrdev_release,
	.open = gpio_chrdev_open,
	.owner = THIS_MODULE,
	.llseek = noop_llseek,
	.unlocked_ioctl = gpio_ioctl,
938 939 940
#ifdef CONFIG_COMPAT
	.compat_ioctl = gpio_ioctl_compat,
#endif
941 942
};

943 944 945 946
static void gpiodevice_release(struct device *dev)
{
	struct gpio_device *gdev = dev_get_drvdata(dev);

947
	cdev_del(&gdev->chrdev);
948 949
	list_del(&gdev->list);
	ida_simple_remove(&gpio_ida, gdev->id);
950 951
	kfree(gdev->label);
	kfree(gdev->descs);
952
	kfree(gdev);
953 954
}

955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006
static int gpiochip_setup_dev(struct gpio_device *gdev)
{
	int status;

	cdev_init(&gdev->chrdev, &gpio_fileops);
	gdev->chrdev.owner = THIS_MODULE;
	gdev->chrdev.kobj.parent = &gdev->dev.kobj;
	gdev->dev.devt = MKDEV(MAJOR(gpio_devt), gdev->id);
	status = cdev_add(&gdev->chrdev, gdev->dev.devt, 1);
	if (status < 0)
		chip_warn(gdev->chip, "failed to add char device %d:%d\n",
			  MAJOR(gpio_devt), gdev->id);
	else
		chip_dbg(gdev->chip, "added GPIO chardev (%d:%d)\n",
			 MAJOR(gpio_devt), gdev->id);
	status = device_add(&gdev->dev);
	if (status)
		goto err_remove_chardev;

	status = gpiochip_sysfs_register(gdev);
	if (status)
		goto err_remove_device;

	/* From this point, the .release() function cleans up gpio_device */
	gdev->dev.release = gpiodevice_release;
	get_device(&gdev->dev);
	pr_debug("%s: registered GPIOs %d to %d on device: %s (%s)\n",
		 __func__, gdev->base, gdev->base + gdev->ngpio - 1,
		 dev_name(&gdev->dev), gdev->chip->label ? : "generic");

	return 0;

err_remove_device:
	device_del(&gdev->dev);
err_remove_chardev:
	cdev_del(&gdev->chrdev);
	return status;
}

static void gpiochip_setup_devs(void)
{
	struct gpio_device *gdev;
	int err;

	list_for_each_entry(gdev, &gpio_devices, list) {
		err = gpiochip_setup_dev(gdev);
		if (err)
			pr_err("%s: Failed to initialize gpio device (%d)\n",
			       dev_name(&gdev->dev), err);
	}
}

1007
/**
1008
 * gpiochip_add_data() - register a gpio_chip
1009
 * @chip: the chip to register, with chip->base initialized
1010
 * Context: potentially before irqs will work
1011 1012 1013 1014
 *
 * 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.
1015
 *
1016
 * When gpiochip_add_data() is called very early during boot, so that GPIOs
1017
 * can be freely used, the chip->parent device must be registered before
David Brownell's avatar
David Brownell committed
1018 1019 1020
 * the gpio framework's arch_initcall().  Otherwise sysfs initialization
 * for GPIOs will fail rudely.
 *
1021 1022 1023
 * gpiochip_add_data() must only be called after gpiolib initialization,
 * ie after core_initcall().
 *
1024 1025
 * If chip->base is negative, this requests dynamic assignment of
 * a range of valid GPIOs.
1026
 */
1027
int gpiochip_add_data(struct gpio_chip *chip, void *data)
1028 1029 1030
{
	unsigned long	flags;
	int		status = 0;
1031
	unsigned	i;
1032
	int		base = chip->base;
1033
	struct gpio_device *gdev;
1034

1035 1036 1037 1038
	/*
	 * First: allocate and populate the internal stat container, and
	 * set up the struct device.
	 */
1039
	gdev = kzalloc(sizeof(*gdev), GFP_KERNEL);
1040
	if (!gdev)
1041
		return -ENOMEM;
1042
	gdev->dev.bus = &gpio_bus_type;
1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069
	gdev->chip = chip;
	chip->gpiodev = gdev;
	if (chip->parent) {
		gdev->dev.parent = chip->parent;
		gdev->dev.of_node = chip->parent->of_node;
	} else {
#ifdef CONFIG_OF_GPIO
	/* If the gpiochip has an assigned OF node this takes precedence */
		if (chip->of_node)
			gdev->dev.of_node = chip->of_node;
#endif
	}
	gdev->id = ida_simple_get(&gpio_ida, 0, 0, GFP_KERNEL);
	if (gdev->id < 0) {
		status = gdev->id;
		goto err_free_gdev;
	}
	dev_set_name(&gdev->dev, "gpiochip%d", gdev->id);
	device_initialize(&gdev->dev);
	dev_set_drvdata(&gdev->dev, gdev);
	if (chip->parent && chip->parent->driver)
		gdev->owner = chip->parent->driver->owner;
	else if (chip->owner)
		/* TODO: remove chip->owner */
		gdev->owner = chip->owner;
	else
		gdev->owner = THIS_MODULE;
1070

1071
	gdev->descs = kcalloc(chip->ngpio, sizeof(gdev->descs[0]), GFP_KERNEL);
1072
	if (!gdev->descs) {
1073 1074 1075 1076
		status = -ENOMEM;
		goto err_free_gdev;
	}

1077 1078
	if (chip->ngpio == 0) {
		chip_err(chip, "tried to insert a GPIO chip with zero lines\n");
1079
		status = -EINVAL;
1080
		goto err_free_descs;
1081
	}
1082 1083

	if (chip->label)
1084
		gdev->label = kstrdup(chip->label, GFP_KERNEL);
1085
	else
1086
		gdev->label = kstrdup("unknown", GFP_KERNEL);
1087 1088
	if (!gdev->label) {
		status = -ENOMEM;
1089
		goto err_free_descs;
1090 1091
	}

1092
	gdev->ngpio = chip->ngpio;
1093
	gdev->data = data;
1094

1095 1096
	spin_lock_irqsave(&gpio_lock, flags);

1097 1098 1099 1100 1101 1102 1103
	/*
	 * TODO: this allocates a Linux GPIO number base in the global
	 * GPIO numberspace for this chip. In the long run we want to
	 * get *rid* of this numberspace and use only descriptors, but
	 * it may be a pipe dream. It will not happen before we get rid
	 * of the sysfs interface anyways.
	 */
1104 1105 1106 1107
	if (base < 0) {
		base = gpiochip_find_base(chip->ngpio);
		if (base < 0) {
			status = base;
1108
			spin_unlock_irqrestore(&gpio_lock, flags);
1109
			goto err_free_label;
1110
		}
1111 1112 1113 1114 1115 1116
		/*
		 * TODO: it should not be necessary to reflect the assigned
		 * base outside of the GPIO subsystem. Go over drivers and
		 * see if anyone makes use of this, else drop this and assign
		 * a poison instead.
		 */
1117 1118
		chip->base = base;
	}
1119
	gdev->base = base;
1120

1121
	status = gpiodev_add_to_list(gdev);
1122 1123
	if (status) {
		spin_unlock_irqrestore(&gpio_lock, flags);
1124
		goto err_free_label;
1125
	}
1126

1127 1128
	spin_unlock_irqrestore(&gpio_lock, flags);

1129
	for (i = 0; i < chip->ngpio; i++) {
1130
		struct gpio_desc *desc = &gdev->descs[i];
1131

1132
		desc->gdev = gdev;
1133 1134 1135 1136 1137 1138 1139
		/*
		 * 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.
1140
		 */
1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157

		if (chip->get_direction) {
			/*
			 * If we have .get_direction, set up the initial
			 * direction flag from the hardware.
			 */
			int dir = chip->get_direction(chip, i);

			if (!dir)
				set_bit(FLAG_IS_OUT, &desc->flags);
		} else if (!chip->direction_input) {
			/*
			 * If the chip lacks the .direction_input callback
			 * we logically assume all lines are outputs.
			 */
			set_bit(FLAG_IS_OUT, &desc->flags);
		}
1158
	}
1159

1160
#ifdef CONFIG_PINCTRL
1161
	INIT_LIST_HEAD(&gdev->pin_ranges);
1162 1163
#endif

1164 1165 1166 1167
	status = gpiochip_set_desc_names(chip);
	if (status)
		goto err_remove_from_list;

1168 1169 1170 1171
	status = of_gpiochip_add(chip);
	if (status)
		goto err_remove_chip;

1172
	acpi_gpiochip_add(chip);
1173

1174 1175 1176 1177 1178
	/*
	 * By first adding the chardev, and then adding the device,
	 * we get a device node entry in sysfs under
	 * /sys/bus/gpio/devices/gpiochipN/dev that can be used for
	 * coldplug of device nodes and other udev business.
1179 1180
	 * We can do this only if gpiolib has been initialized.
	 * Otherwise, defer until later.
1181
	 */
1182 1183 1184 1185 1186
	if (gpiolib_initialized) {
		status = gpiochip_setup_dev(gdev);
		if (status)
			goto err_remove_chip;
	}
1187
	return 0;
1188

1189 1190
err_remove_chip:
	acpi_gpiochip_remove(chip);
1191
	gpiochip_free_hogs(chip);
1192
	of_gpiochip_remove(chip);
1193
err_remove_from_list:
1194
	spin_lock_irqsave(&gpio_lock, flags);
1195
	list_del(&gdev->list);
1196
	spin_unlock_irqrestore(&gpio_lock, flags);
1197 1198 1199 1200
err_free_label:
	kfree(gdev->label);
err_free_descs:
	kfree(gdev->descs);
1201 1202
err_free_gdev:
	ida_simple_remove(&gpio_ida, gdev->id);
1203
	/* failures here can mean systems won't boot... */
1204
	pr_err("%s: GPIOs %d..%d (%s) failed to register\n", __func__,
1205 1206 1207
	       gdev->base, gdev->base + gdev->ngpio - 1,
	       chip->label ? : "generic");
	kfree(gdev);
1208 1209
	return status;
}
1210
EXPORT_SYMBOL_GPL(gpiochip_add_data);
1211

1212 1213 1214 1215 1216 1217 1218 1219 1220
/**
 * gpiochip_get_data() - get per-subdriver data for the chip
 */
void *gpiochip_get_data(struct gpio_chip *chip)
{
	return chip->gpiodev->data;
}
EXPORT_SYMBOL_GPL(gpiochip_get_data);

1221 1222 1223 1224 1225 1226
/**
 * gpiochip_remove() - unregister a gpio_chip
 * @chip: the chip to unregister
 *
 * A gpio_chip with any GPIOs still requested may not be removed.
 */
1227
void gpiochip_remove(struct gpio_chip *chip)
1228
{
1229
	struct gpio_device *gdev = chip->gpiodev;
Johan Hovold's avatar
Johan Hovold committed
1230
	struct gpio_desc *desc;
1231
	unsigned long	flags;
1232
	unsigned	i;
Johan Hovold's avatar
Johan Hovold committed
1233
	bool		requested = false;
1234

1235
	/* FIXME: should the legacy sysfs handling be moved to gpio_device? */
1236
	gpiochip_sysfs_unregister(gdev);
1237 1238
	/* Numb the device, cancelling all outstanding operations */
	gdev->chip = NULL;
1239
	gpiochip_irqchip_remove(chip);
1240
	acpi_gpiochip_remove(chip);
1241
	gpiochip_remove_pin_ranges(chip);
1242
	gpiochip_free_hogs(chip);
1243
	of_gpiochip_remove(chip);
1244 1245 1246 1247 1248
	/*
	 * We accept no more calls into the driver from this point, so
	 * NULL the driver data pointer
	 */
	gdev->data = NULL;
1249

1250
	spin_lock_irqsave(&gpio_lock, flags);
1251
	for (i = 0; i < gdev->ngpio; i++) {
1252
		desc = &gdev->descs[i];
Johan Hovold's avatar
Johan Hovold committed
1253 1254
		if (test_bit(FLAG_REQUESTED, &desc->flags))
			requested = true;
1255 1256
	}
	spin_unlock_irqrestore(&gpio_lock, flags);
1257

Johan Hovold's avatar
Johan Hovold committed
1258
	if (requested)
1259
		dev_crit(&gdev->dev,
1260
			 "REMOVING GPIOCHIP WITH GPIOS STILL REQUESTED\n");
Johan Hovold's avatar
Johan Hovold committed
1261

1262 1263 1264 1265 1266 1267 1268
	/*
	 * The gpiochip side puts its use of the device to rest here:
	 * if there are no userspace clients, the chardev and device will
	 * be removed, else it will be dangling until the last user is
	 * gone.
	 */
	put_device(&gdev->dev);
1269 1270 1271
}
EXPORT_SYMBOL_GPL(gpiochip_remove);

1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320