1 #include <linux/kernel.h>
2 #include <linux/module.h>
3 #include <linux/interrupt.h>
5 #include <linux/spinlock.h>
6 #include <linux/list.h>
7 #include <linux/device.h>
9 #include <linux/debugfs.h>
10 #include <linux/seq_file.h>
11 #include <linux/gpio.h>
12 #include <linux/of_gpio.h>
13 #include <linux/idr.h>
14 #include <linux/slab.h>
15 #include <linux/acpi.h>
16 #include <linux/gpio/driver.h>
17 #include <linux/gpio/machine.h>
21 #define CREATE_TRACE_POINTS
22 #include <trace/events/gpio.h>
24 /* Implementation infrastructure for GPIO interfaces.
26 * The GPIO programming interface allows for inlining speed-critical
27 * get/set operations for common cases, so that access to SOC-integrated
28 * GPIOs can sometimes cost only an instruction or two per bit.
32 /* When debugging, extend minimal trust to callers and platform code.
33 * Also emit diagnostic messages that may help initial bringup, when
34 * board setup or driver bugs are most common.
36 * Otherwise, minimize overhead in what may be bitbanging codepaths.
39 #define extra_checks 1
41 #define extra_checks 0
44 /* gpio_lock prevents conflicts during gpio_desc[] table updates.
45 * While any GPIO is requested, its gpio_chip is not removable;
46 * each GPIO's "requested" flag serves as a lock and refcount.
48 DEFINE_SPINLOCK(gpio_lock);
50 static struct gpio_desc gpio_desc[ARCH_NR_GPIOS];
52 #define GPIO_OFFSET_VALID(chip, offset) (offset >= 0 && offset < chip->ngpio)
54 static DEFINE_MUTEX(gpio_lookup_lock);
55 static LIST_HEAD(gpio_lookup_list);
56 LIST_HEAD(gpio_chips);
58 static inline void desc_set_label(struct gpio_desc *d, const char *label)
64 * Convert a GPIO number to its descriptor
66 struct gpio_desc *gpio_to_desc(unsigned gpio)
68 if (WARN(!gpio_is_valid(gpio), "invalid GPIO %d\n", gpio))
71 return &gpio_desc[gpio];
73 EXPORT_SYMBOL_GPL(gpio_to_desc);
76 * Get the GPIO descriptor corresponding to the given hw number for this chip.
78 struct gpio_desc *gpiochip_get_desc(struct gpio_chip *chip,
81 if (hwnum >= chip->ngpio)
82 return ERR_PTR(-EINVAL);
84 return &chip->desc[hwnum];
88 * Convert a GPIO descriptor to the integer namespace.
89 * This should disappear in the future but is needed since we still
90 * use GPIO numbers for error messages and sysfs nodes
92 int desc_to_gpio(const struct gpio_desc *desc)
94 return desc - &gpio_desc[0];
96 EXPORT_SYMBOL_GPL(desc_to_gpio);
100 * gpiod_to_chip - Return the GPIO chip to which a GPIO descriptor belongs
101 * @desc: descriptor to return the chip of
103 struct gpio_chip *gpiod_to_chip(const struct gpio_desc *desc)
105 return desc ? desc->chip : NULL;
107 EXPORT_SYMBOL_GPL(gpiod_to_chip);
109 /* dynamic allocation of GPIOs, e.g. on a hotplugged device */
110 static int gpiochip_find_base(int ngpio)
112 struct gpio_chip *chip;
113 int base = ARCH_NR_GPIOS - ngpio;
115 list_for_each_entry_reverse(chip, &gpio_chips, list) {
116 /* found a free space? */
117 if (chip->base + chip->ngpio <= base)
120 /* nope, check the space right before the chip */
121 base = chip->base - ngpio;
124 if (gpio_is_valid(base)) {
125 pr_debug("%s: found new base at %d\n", __func__, base);
128 pr_err("%s: cannot find free range\n", __func__);
134 * gpiod_get_direction - return the current direction of a GPIO
135 * @desc: GPIO to get the direction of
137 * Return GPIOF_DIR_IN or GPIOF_DIR_OUT, or an error code in case of error.
139 * This function may sleep if gpiod_cansleep() is true.
141 int gpiod_get_direction(const struct gpio_desc *desc)
143 struct gpio_chip *chip;
145 int status = -EINVAL;
147 chip = gpiod_to_chip(desc);
148 offset = gpio_chip_hwgpio(desc);
150 if (!chip->get_direction)
153 status = chip->get_direction(chip, offset);
155 /* GPIOF_DIR_IN, or other positive */
157 /* FLAG_IS_OUT is just a cache of the result of get_direction(),
158 * so it does not affect constness per se */
159 clear_bit(FLAG_IS_OUT, &((struct gpio_desc *)desc)->flags);
163 set_bit(FLAG_IS_OUT, &((struct gpio_desc *)desc)->flags);
167 EXPORT_SYMBOL_GPL(gpiod_get_direction);
170 * Add a new chip to the global chips list, keeping the list of chips sorted
173 * Return -EBUSY if the new chip overlaps with some other chip's integer
176 static int gpiochip_add_to_list(struct gpio_chip *chip)
178 struct list_head *pos = &gpio_chips;
179 struct gpio_chip *_chip;
182 /* find where to insert our chip */
183 list_for_each(pos, &gpio_chips) {
184 _chip = list_entry(pos, struct gpio_chip, list);
185 /* shall we insert before _chip? */
186 if (_chip->base >= chip->base + chip->ngpio)
190 /* are we stepping on the chip right before? */
191 if (pos != &gpio_chips && pos->prev != &gpio_chips) {
192 _chip = list_entry(pos->prev, struct gpio_chip, list);
193 if (_chip->base + _chip->ngpio > chip->base) {
195 "GPIO integer space overlap, cannot add chip\n");
201 list_add_tail(&chip->list, pos);
207 * gpiochip_add() - register a gpio_chip
208 * @chip: the chip to register, with chip->base initialized
209 * Context: potentially before irqs or kmalloc will work
211 * Returns a negative errno if the chip can't be registered, such as
212 * because the chip->base is invalid or already associated with a
213 * different chip. Otherwise it returns zero as a success code.
215 * When gpiochip_add() is called very early during boot, so that GPIOs
216 * can be freely used, the chip->dev device must be registered before
217 * the gpio framework's arch_initcall(). Otherwise sysfs initialization
218 * for GPIOs will fail rudely.
220 * If chip->base is negative, this requests dynamic assignment of
221 * a range of valid GPIOs.
223 int gpiochip_add(struct gpio_chip *chip)
228 int base = chip->base;
230 if ((!gpio_is_valid(base) || !gpio_is_valid(base + chip->ngpio - 1))
236 spin_lock_irqsave(&gpio_lock, flags);
239 base = gpiochip_find_base(chip->ngpio);
247 status = gpiochip_add_to_list(chip);
250 chip->desc = &gpio_desc[chip->base];
252 for (id = 0; id < chip->ngpio; id++) {
253 struct gpio_desc *desc = &chip->desc[id];
256 /* REVISIT: most hardware initializes GPIOs as
257 * inputs (often with pullups enabled) so power
258 * usage is minimized. Linux code should set the
259 * gpio direction first thing; but until it does,
260 * and in case chip->get_direction is not set,
261 * we may expose the wrong direction in sysfs.
263 desc->flags = !chip->direction_input
269 spin_unlock_irqrestore(&gpio_lock, flags);
271 #ifdef CONFIG_PINCTRL
272 INIT_LIST_HEAD(&chip->pin_ranges);
275 of_gpiochip_add(chip);
276 acpi_gpiochip_add(chip);
281 status = gpiochip_export(chip);
285 pr_debug("%s: registered GPIOs %d to %d on device: %s\n", __func__,
286 chip->base, chip->base + chip->ngpio - 1,
287 chip->label ? : "generic");
292 spin_unlock_irqrestore(&gpio_lock, flags);
294 /* failures here can mean systems won't boot... */
295 pr_err("%s: GPIOs %d..%d (%s) failed to register\n", __func__,
296 chip->base, chip->base + chip->ngpio - 1,
297 chip->label ? : "generic");
300 EXPORT_SYMBOL_GPL(gpiochip_add);
302 /* Forward-declaration */
303 static void gpiochip_irqchip_remove(struct gpio_chip *gpiochip);
306 * gpiochip_remove() - unregister a gpio_chip
307 * @chip: the chip to unregister
309 * A gpio_chip with any GPIOs still requested may not be removed.
311 void gpiochip_remove(struct gpio_chip *chip)
316 acpi_gpiochip_remove(chip);
318 spin_lock_irqsave(&gpio_lock, flags);
320 gpiochip_irqchip_remove(chip);
321 gpiochip_remove_pin_ranges(chip);
322 of_gpiochip_remove(chip);
324 for (id = 0; id < chip->ngpio; id++) {
325 if (test_bit(FLAG_REQUESTED, &chip->desc[id].flags))
326 dev_crit(chip->dev, "REMOVING GPIOCHIP WITH GPIOS STILL REQUESTED\n");
328 for (id = 0; id < chip->ngpio; id++)
329 chip->desc[id].chip = NULL;
331 list_del(&chip->list);
332 spin_unlock_irqrestore(&gpio_lock, flags);
333 gpiochip_unexport(chip);
335 EXPORT_SYMBOL_GPL(gpiochip_remove);
338 * gpiochip_find() - iterator for locating a specific gpio_chip
339 * @data: data to pass to match function
340 * @callback: Callback function to check gpio_chip
342 * Similar to bus_find_device. It returns a reference to a gpio_chip as
343 * determined by a user supplied @match callback. The callback should return
344 * 0 if the device doesn't match and non-zero if it does. If the callback is
345 * non-zero, this function will return to the caller and not iterate over any
348 struct gpio_chip *gpiochip_find(void *data,
349 int (*match)(struct gpio_chip *chip,
352 struct gpio_chip *chip;
355 spin_lock_irqsave(&gpio_lock, flags);
356 list_for_each_entry(chip, &gpio_chips, list)
357 if (match(chip, data))
361 if (&chip->list == &gpio_chips)
363 spin_unlock_irqrestore(&gpio_lock, flags);
367 EXPORT_SYMBOL_GPL(gpiochip_find);
369 static int gpiochip_match_name(struct gpio_chip *chip, void *data)
371 const char *name = data;
373 return !strcmp(chip->label, name);
376 static struct gpio_chip *find_chip_by_name(const char *name)
378 return gpiochip_find((void *)name, gpiochip_match_name);
381 #ifdef CONFIG_GPIOLIB_IRQCHIP
384 * The following is irqchip helper code for gpiochips.
388 * gpiochip_set_chained_irqchip() - sets a chained irqchip to a gpiochip
389 * @gpiochip: the gpiochip to set the irqchip chain to
390 * @irqchip: the irqchip to chain to the gpiochip
391 * @parent_irq: the irq number corresponding to the parent IRQ for this
393 * @parent_handler: the parent interrupt handler for the accumulated IRQ
394 * coming out of the gpiochip. If the interrupt is nested rather than
395 * cascaded, pass NULL in this handler argument
397 void gpiochip_set_chained_irqchip(struct gpio_chip *gpiochip,
398 struct irq_chip *irqchip,
400 irq_flow_handler_t parent_handler)
404 if (!gpiochip->irqdomain) {
405 chip_err(gpiochip, "called %s before setting up irqchip\n",
410 if (parent_handler) {
411 if (gpiochip->can_sleep) {
413 "you cannot have chained interrupts on a "
414 "chip that may sleep\n");
418 * The parent irqchip is already using the chip_data for this
419 * irqchip, so our callbacks simply use the handler_data.
421 irq_set_handler_data(parent_irq, gpiochip);
422 irq_set_chained_handler(parent_irq, parent_handler);
425 /* Set the parent IRQ for all affected IRQs */
426 for (offset = 0; offset < gpiochip->ngpio; offset++)
427 irq_set_parent(irq_find_mapping(gpiochip->irqdomain, offset),
430 EXPORT_SYMBOL_GPL(gpiochip_set_chained_irqchip);
433 * This lock class tells lockdep that GPIO irqs are in a different
434 * category than their parents, so it won't report false recursion.
436 static struct lock_class_key gpiochip_irq_lock_class;
439 * gpiochip_irq_map() - maps an IRQ into a GPIO irqchip
440 * @d: the irqdomain used by this irqchip
441 * @irq: the global irq number used by this GPIO irqchip irq
442 * @hwirq: the local IRQ/GPIO line offset on this gpiochip
444 * This function will set up the mapping for a certain IRQ line on a
445 * gpiochip by assigning the gpiochip as chip data, and using the irqchip
446 * stored inside the gpiochip.
448 static int gpiochip_irq_map(struct irq_domain *d, unsigned int irq,
449 irq_hw_number_t hwirq)
451 struct gpio_chip *chip = d->host_data;
453 irq_set_chip_data(irq, chip);
454 irq_set_lockdep_class(irq, &gpiochip_irq_lock_class);
455 irq_set_chip_and_handler(irq, chip->irqchip, chip->irq_handler);
456 /* Chips that can sleep need nested thread handlers */
457 if (chip->can_sleep && !chip->irq_not_threaded)
458 irq_set_nested_thread(irq, 1);
460 set_irq_flags(irq, IRQF_VALID);
462 irq_set_noprobe(irq);
465 * No set-up of the hardware will happen if IRQ_TYPE_NONE
466 * is passed as default type.
468 if (chip->irq_default_type != IRQ_TYPE_NONE)
469 irq_set_irq_type(irq, chip->irq_default_type);
474 static void gpiochip_irq_unmap(struct irq_domain *d, unsigned int irq)
476 struct gpio_chip *chip = d->host_data;
479 set_irq_flags(irq, 0);
482 irq_set_nested_thread(irq, 0);
483 irq_set_chip_and_handler(irq, NULL, NULL);
484 irq_set_chip_data(irq, NULL);
487 static const struct irq_domain_ops gpiochip_domain_ops = {
488 .map = gpiochip_irq_map,
489 .unmap = gpiochip_irq_unmap,
490 /* Virtually all GPIO irqchips are twocell:ed */
491 .xlate = irq_domain_xlate_twocell,
494 static int gpiochip_irq_reqres(struct irq_data *d)
496 struct gpio_chip *chip = irq_data_get_irq_chip_data(d);
498 if (gpio_lock_as_irq(chip, d->hwirq)) {
500 "unable to lock HW IRQ %lu for IRQ\n",
507 static void gpiochip_irq_relres(struct irq_data *d)
509 struct gpio_chip *chip = irq_data_get_irq_chip_data(d);
511 gpio_unlock_as_irq(chip, d->hwirq);
514 static int gpiochip_to_irq(struct gpio_chip *chip, unsigned offset)
516 return irq_find_mapping(chip->irqdomain, offset);
520 * gpiochip_irqchip_remove() - removes an irqchip added to a gpiochip
521 * @gpiochip: the gpiochip to remove the irqchip from
523 * This is called only from gpiochip_remove()
525 static void gpiochip_irqchip_remove(struct gpio_chip *gpiochip)
529 acpi_gpiochip_free_interrupts(gpiochip);
531 /* Remove all IRQ mappings and delete the domain */
532 if (gpiochip->irqdomain) {
533 for (offset = 0; offset < gpiochip->ngpio; offset++)
535 irq_find_mapping(gpiochip->irqdomain, offset));
536 irq_domain_remove(gpiochip->irqdomain);
539 if (gpiochip->irqchip) {
540 gpiochip->irqchip->irq_request_resources = NULL;
541 gpiochip->irqchip->irq_release_resources = NULL;
542 gpiochip->irqchip = NULL;
547 * gpiochip_irqchip_add() - adds an irqchip to a gpiochip
548 * @gpiochip: the gpiochip to add the irqchip to
549 * @irqchip: the irqchip to add to the gpiochip
550 * @first_irq: if not dynamically assigned, the base (first) IRQ to
551 * allocate gpiochip irqs from
552 * @handler: the irq handler to use (often a predefined irq core function)
553 * @type: the default type for IRQs on this irqchip, pass IRQ_TYPE_NONE
554 * to have the core avoid setting up any default type in the hardware.
556 * This function closely associates a certain irqchip with a certain
557 * gpiochip, providing an irq domain to translate the local IRQs to
558 * global irqs in the gpiolib core, and making sure that the gpiochip
559 * is passed as chip data to all related functions. Driver callbacks
560 * need to use container_of() to get their local state containers back
561 * from the gpiochip passed as chip data. An irqdomain will be stored
562 * in the gpiochip that shall be used by the driver to handle IRQ number
563 * translation. The gpiochip will need to be initialized and registered
564 * before calling this function.
566 * This function will handle two cell:ed simple IRQs and assumes all
567 * the pins on the gpiochip can generate a unique IRQ. Everything else
568 * need to be open coded.
570 int gpiochip_irqchip_add(struct gpio_chip *gpiochip,
571 struct irq_chip *irqchip,
572 unsigned int first_irq,
573 irq_flow_handler_t handler,
576 struct device_node *of_node;
578 unsigned irq_base = 0;
580 if (!gpiochip || !irqchip)
583 if (!gpiochip->dev) {
584 pr_err("missing gpiochip .dev parent pointer\n");
587 of_node = gpiochip->dev->of_node;
588 #ifdef CONFIG_OF_GPIO
590 * If the gpiochip has an assigned OF node this takes precendence
591 * FIXME: get rid of this and use gpiochip->dev->of_node everywhere
593 if (gpiochip->of_node)
594 of_node = gpiochip->of_node;
596 gpiochip->irqchip = irqchip;
597 gpiochip->irq_handler = handler;
598 gpiochip->irq_default_type = type;
599 gpiochip->to_irq = gpiochip_to_irq;
600 gpiochip->irqdomain = irq_domain_add_simple(of_node,
601 gpiochip->ngpio, first_irq,
602 &gpiochip_domain_ops, gpiochip);
603 if (!gpiochip->irqdomain) {
604 gpiochip->irqchip = NULL;
607 irqchip->irq_request_resources = gpiochip_irq_reqres;
608 irqchip->irq_release_resources = gpiochip_irq_relres;
611 * Prepare the mapping since the irqchip shall be orthogonal to
612 * any gpiochip calls. If the first_irq was zero, this is
613 * necessary to allocate descriptors for all IRQs.
615 for (offset = 0; offset < gpiochip->ngpio; offset++) {
616 irq_base = irq_create_mapping(gpiochip->irqdomain, offset);
619 * Store the base into the gpiochip to be used when
620 * unmapping the irqs.
622 gpiochip->irq_base = irq_base;
625 acpi_gpiochip_request_interrupts(gpiochip);
629 EXPORT_SYMBOL_GPL(gpiochip_irqchip_add);
631 #else /* CONFIG_GPIOLIB_IRQCHIP */
633 static void gpiochip_irqchip_remove(struct gpio_chip *gpiochip) {}
635 #endif /* CONFIG_GPIOLIB_IRQCHIP */
637 #ifdef CONFIG_PINCTRL
640 * gpiochip_add_pingroup_range() - add a range for GPIO <-> pin mapping
641 * @chip: the gpiochip to add the range for
642 * @pinctrl: the dev_name() of the pin controller to map to
643 * @gpio_offset: the start offset in the current gpio_chip number space
644 * @pin_group: name of the pin group inside the pin controller
646 int gpiochip_add_pingroup_range(struct gpio_chip *chip,
647 struct pinctrl_dev *pctldev,
648 unsigned int gpio_offset, const char *pin_group)
650 struct gpio_pin_range *pin_range;
653 pin_range = kzalloc(sizeof(*pin_range), GFP_KERNEL);
655 chip_err(chip, "failed to allocate pin ranges\n");
659 /* Use local offset as range ID */
660 pin_range->range.id = gpio_offset;
661 pin_range->range.gc = chip;
662 pin_range->range.name = chip->label;
663 pin_range->range.base = chip->base + gpio_offset;
664 pin_range->pctldev = pctldev;
666 ret = pinctrl_get_group_pins(pctldev, pin_group,
667 &pin_range->range.pins,
668 &pin_range->range.npins);
674 pinctrl_add_gpio_range(pctldev, &pin_range->range);
676 chip_dbg(chip, "created GPIO range %d->%d ==> %s PINGRP %s\n",
677 gpio_offset, gpio_offset + pin_range->range.npins - 1,
678 pinctrl_dev_get_devname(pctldev), pin_group);
680 list_add_tail(&pin_range->node, &chip->pin_ranges);
684 EXPORT_SYMBOL_GPL(gpiochip_add_pingroup_range);
687 * gpiochip_add_pin_range() - add a range for GPIO <-> pin mapping
688 * @chip: the gpiochip to add the range for
689 * @pinctrl_name: the dev_name() of the pin controller to map to
690 * @gpio_offset: the start offset in the current gpio_chip number space
691 * @pin_offset: the start offset in the pin controller number space
692 * @npins: the number of pins from the offset of each pin space (GPIO and
693 * pin controller) to accumulate in this range
695 int gpiochip_add_pin_range(struct gpio_chip *chip, const char *pinctl_name,
696 unsigned int gpio_offset, unsigned int pin_offset,
699 struct gpio_pin_range *pin_range;
702 pin_range = kzalloc(sizeof(*pin_range), GFP_KERNEL);
704 chip_err(chip, "failed to allocate pin ranges\n");
708 /* Use local offset as range ID */
709 pin_range->range.id = gpio_offset;
710 pin_range->range.gc = chip;
711 pin_range->range.name = chip->label;
712 pin_range->range.base = chip->base + gpio_offset;
713 pin_range->range.pin_base = pin_offset;
714 pin_range->range.npins = npins;
715 pin_range->pctldev = pinctrl_find_and_add_gpio_range(pinctl_name,
717 if (IS_ERR(pin_range->pctldev)) {
718 ret = PTR_ERR(pin_range->pctldev);
719 chip_err(chip, "could not create pin range\n");
723 chip_dbg(chip, "created GPIO range %d->%d ==> %s PIN %d->%d\n",
724 gpio_offset, gpio_offset + npins - 1,
726 pin_offset, pin_offset + npins - 1);
728 list_add_tail(&pin_range->node, &chip->pin_ranges);
732 EXPORT_SYMBOL_GPL(gpiochip_add_pin_range);
735 * gpiochip_remove_pin_ranges() - remove all the GPIO <-> pin mappings
736 * @chip: the chip to remove all the mappings for
738 void gpiochip_remove_pin_ranges(struct gpio_chip *chip)
740 struct gpio_pin_range *pin_range, *tmp;
742 list_for_each_entry_safe(pin_range, tmp, &chip->pin_ranges, node) {
743 list_del(&pin_range->node);
744 pinctrl_remove_gpio_range(pin_range->pctldev,
749 EXPORT_SYMBOL_GPL(gpiochip_remove_pin_ranges);
751 #endif /* CONFIG_PINCTRL */
753 /* These "optional" allocation calls help prevent drivers from stomping
754 * on each other, and help provide better diagnostics in debugfs.
755 * They're called even less than the "set direction" calls.
757 static int __gpiod_request(struct gpio_desc *desc, const char *label)
759 struct gpio_chip *chip = desc->chip;
763 spin_lock_irqsave(&gpio_lock, flags);
765 /* NOTE: gpio_request() can be called in early boot,
766 * before IRQs are enabled, for non-sleeping (SOC) GPIOs.
769 if (test_and_set_bit(FLAG_REQUESTED, &desc->flags) == 0) {
770 desc_set_label(desc, label ? : "?");
778 /* chip->request may sleep */
779 spin_unlock_irqrestore(&gpio_lock, flags);
780 status = chip->request(chip, gpio_chip_hwgpio(desc));
781 spin_lock_irqsave(&gpio_lock, flags);
784 desc_set_label(desc, NULL);
785 clear_bit(FLAG_REQUESTED, &desc->flags);
789 if (chip->get_direction) {
790 /* chip->get_direction may sleep */
791 spin_unlock_irqrestore(&gpio_lock, flags);
792 gpiod_get_direction(desc);
793 spin_lock_irqsave(&gpio_lock, flags);
796 spin_unlock_irqrestore(&gpio_lock, flags);
800 int gpiod_request(struct gpio_desc *desc, const char *label)
802 int status = -EPROBE_DEFER;
803 struct gpio_chip *chip;
806 pr_warn("%s: invalid GPIO\n", __func__);
814 if (try_module_get(chip->owner)) {
815 status = __gpiod_request(desc, label);
817 module_put(chip->owner);
822 gpiod_dbg(desc, "%s: status %d\n", __func__, status);
827 static bool __gpiod_free(struct gpio_desc *desc)
831 struct gpio_chip *chip;
835 gpiod_unexport(desc);
837 spin_lock_irqsave(&gpio_lock, flags);
840 if (chip && test_bit(FLAG_REQUESTED, &desc->flags)) {
842 spin_unlock_irqrestore(&gpio_lock, flags);
843 might_sleep_if(chip->can_sleep);
844 chip->free(chip, gpio_chip_hwgpio(desc));
845 spin_lock_irqsave(&gpio_lock, flags);
847 desc_set_label(desc, NULL);
848 clear_bit(FLAG_ACTIVE_LOW, &desc->flags);
849 clear_bit(FLAG_REQUESTED, &desc->flags);
850 clear_bit(FLAG_OPEN_DRAIN, &desc->flags);
851 clear_bit(FLAG_OPEN_SOURCE, &desc->flags);
855 spin_unlock_irqrestore(&gpio_lock, flags);
859 void gpiod_free(struct gpio_desc *desc)
861 if (desc && __gpiod_free(desc))
862 module_put(desc->chip->owner);
864 WARN_ON(extra_checks);
868 * gpiochip_is_requested - return string iff signal was requested
869 * @chip: controller managing the signal
870 * @offset: of signal within controller's 0..(ngpio - 1) range
872 * Returns NULL if the GPIO is not currently requested, else a string.
873 * The string returned is the label passed to gpio_request(); if none has been
874 * passed it is a meaningless, non-NULL constant.
876 * This function is for use by GPIO controller drivers. The label can
877 * help with diagnostics, and knowing that the signal is used as a GPIO
878 * can help avoid accidentally multiplexing it to another controller.
880 const char *gpiochip_is_requested(struct gpio_chip *chip, unsigned offset)
882 struct gpio_desc *desc;
884 if (!GPIO_OFFSET_VALID(chip, offset))
887 desc = &chip->desc[offset];
889 if (test_bit(FLAG_REQUESTED, &desc->flags) == 0)
893 EXPORT_SYMBOL_GPL(gpiochip_is_requested);
896 * gpiochip_request_own_desc - Allow GPIO chip to request its own descriptor
897 * @desc: GPIO descriptor to request
898 * @label: label for the GPIO
900 * Function allows GPIO chip drivers to request and use their own GPIO
901 * descriptors via gpiolib API. Difference to gpiod_request() is that this
902 * function will not increase reference count of the GPIO chip module. This
903 * allows the GPIO chip module to be unloaded as needed (we assume that the
904 * GPIO chip driver handles freeing the GPIOs it has requested).
906 struct gpio_desc *gpiochip_request_own_desc(struct gpio_chip *chip, u16 hwnum,
909 struct gpio_desc *desc = gpiochip_get_desc(chip, hwnum);
913 chip_err(chip, "failed to get GPIO descriptor\n");
917 err = __gpiod_request(desc, label);
923 EXPORT_SYMBOL_GPL(gpiochip_request_own_desc);
926 * gpiochip_free_own_desc - Free GPIO requested by the chip driver
927 * @desc: GPIO descriptor to free
929 * Function frees the given GPIO requested previously with
930 * gpiochip_request_own_desc().
932 void gpiochip_free_own_desc(struct gpio_desc *desc)
937 EXPORT_SYMBOL_GPL(gpiochip_free_own_desc);
939 /* Drivers MUST set GPIO direction before making get/set calls. In
940 * some cases this is done in early boot, before IRQs are enabled.
942 * As a rule these aren't called more than once (except for drivers
943 * using the open-drain emulation idiom) so these are natural places
944 * to accumulate extra debugging checks. Note that we can't (yet)
945 * rely on gpio_request() having been called beforehand.
949 * gpiod_direction_input - set the GPIO direction to input
950 * @desc: GPIO to set to input
952 * Set the direction of the passed GPIO to input, such as gpiod_get_value() can
953 * be called safely on it.
955 * Return 0 in case of success, else an error code.
957 int gpiod_direction_input(struct gpio_desc *desc)
959 struct gpio_chip *chip;
960 int status = -EINVAL;
962 if (!desc || !desc->chip) {
963 pr_warn("%s: invalid GPIO\n", __func__);
968 if (!chip->get || !chip->direction_input) {
970 "%s: missing get() or direction_input() operations\n",
975 status = chip->direction_input(chip, gpio_chip_hwgpio(desc));
977 clear_bit(FLAG_IS_OUT, &desc->flags);
979 trace_gpio_direction(desc_to_gpio(desc), 1, status);
983 EXPORT_SYMBOL_GPL(gpiod_direction_input);
985 static int _gpiod_direction_output_raw(struct gpio_desc *desc, int value)
987 struct gpio_chip *chip;
988 int status = -EINVAL;
990 /* GPIOs used for IRQs shall not be set as output */
991 if (test_bit(FLAG_USED_AS_IRQ, &desc->flags)) {
993 "%s: tried to set a GPIO tied to an IRQ as output\n",
998 /* Open drain pin should not be driven to 1 */
999 if (value && test_bit(FLAG_OPEN_DRAIN, &desc->flags))
1000 return gpiod_direction_input(desc);
1002 /* Open source pin should not be driven to 0 */
1003 if (!value && test_bit(FLAG_OPEN_SOURCE, &desc->flags))
1004 return gpiod_direction_input(desc);
1007 if (!chip->set || !chip->direction_output) {
1009 "%s: missing set() or direction_output() operations\n",
1014 status = chip->direction_output(chip, gpio_chip_hwgpio(desc), value);
1016 set_bit(FLAG_IS_OUT, &desc->flags);
1017 trace_gpio_value(desc_to_gpio(desc), 0, value);
1018 trace_gpio_direction(desc_to_gpio(desc), 0, status);
1023 * gpiod_direction_output_raw - set the GPIO direction to output
1024 * @desc: GPIO to set to output
1025 * @value: initial output value of the GPIO
1027 * Set the direction of the passed GPIO to output, such as gpiod_set_value() can
1028 * be called safely on it. The initial value of the output must be specified
1029 * as raw value on the physical line without regard for the ACTIVE_LOW status.
1031 * Return 0 in case of success, else an error code.
1033 int gpiod_direction_output_raw(struct gpio_desc *desc, int value)
1035 if (!desc || !desc->chip) {
1036 pr_warn("%s: invalid GPIO\n", __func__);
1039 return _gpiod_direction_output_raw(desc, value);
1041 EXPORT_SYMBOL_GPL(gpiod_direction_output_raw);
1044 * gpiod_direction_output - set the GPIO direction to output
1045 * @desc: GPIO to set to output
1046 * @value: initial output value of the GPIO
1048 * Set the direction of the passed GPIO to output, such as gpiod_set_value() can
1049 * be called safely on it. The initial value of the output must be specified
1050 * as the logical value of the GPIO, i.e. taking its ACTIVE_LOW status into
1053 * Return 0 in case of success, else an error code.
1055 int gpiod_direction_output(struct gpio_desc *desc, int value)
1057 if (!desc || !desc->chip) {
1058 pr_warn("%s: invalid GPIO\n", __func__);
1061 if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
1063 return _gpiod_direction_output_raw(desc, value);
1065 EXPORT_SYMBOL_GPL(gpiod_direction_output);
1068 * gpiod_set_debounce - sets @debounce time for a @gpio
1069 * @gpio: the gpio to set debounce time
1070 * @debounce: debounce time is microseconds
1072 * returns -ENOTSUPP if the controller does not support setting
1075 int gpiod_set_debounce(struct gpio_desc *desc, unsigned debounce)
1077 struct gpio_chip *chip;
1079 if (!desc || !desc->chip) {
1080 pr_warn("%s: invalid GPIO\n", __func__);
1085 if (!chip->set || !chip->set_debounce) {
1087 "%s: missing set() or set_debounce() operations\n",
1092 return chip->set_debounce(chip, gpio_chip_hwgpio(desc), debounce);
1094 EXPORT_SYMBOL_GPL(gpiod_set_debounce);
1097 * gpiod_is_active_low - test whether a GPIO is active-low or not
1098 * @desc: the gpio descriptor to test
1100 * Returns 1 if the GPIO is active-low, 0 otherwise.
1102 int gpiod_is_active_low(const struct gpio_desc *desc)
1104 return test_bit(FLAG_ACTIVE_LOW, &desc->flags);
1106 EXPORT_SYMBOL_GPL(gpiod_is_active_low);
1108 /* I/O calls are only valid after configuration completed; the relevant
1109 * "is this a valid GPIO" error checks should already have been done.
1111 * "Get" operations are often inlinable as reading a pin value register,
1112 * and masking the relevant bit in that register.
1114 * When "set" operations are inlinable, they involve writing that mask to
1115 * one register to set a low value, or a different register to set it high.
1116 * Otherwise locking is needed, so there may be little value to inlining.
1118 *------------------------------------------------------------------------
1120 * IMPORTANT!!! The hot paths -- get/set value -- assume that callers
1121 * have requested the GPIO. That can include implicit requesting by
1122 * a direction setting call. Marking a gpio as requested locks its chip
1123 * in memory, guaranteeing that these table lookups need no more locking
1124 * and that gpiochip_remove() will fail.
1126 * REVISIT when debugging, consider adding some instrumentation to ensure
1127 * that the GPIO was actually requested.
1130 static bool _gpiod_get_raw_value(const struct gpio_desc *desc)
1132 struct gpio_chip *chip;
1137 offset = gpio_chip_hwgpio(desc);
1138 value = chip->get ? chip->get(chip, offset) : false;
1139 trace_gpio_value(desc_to_gpio(desc), 1, value);
1144 * gpiod_get_raw_value() - return a gpio's raw value
1145 * @desc: gpio whose value will be returned
1147 * Return the GPIO's raw value, i.e. the value of the physical line disregarding
1148 * its ACTIVE_LOW status.
1150 * This function should be called from contexts where we cannot sleep, and will
1151 * complain if the GPIO chip functions potentially sleep.
1153 int gpiod_get_raw_value(const struct gpio_desc *desc)
1157 /* Should be using gpio_get_value_cansleep() */
1158 WARN_ON(desc->chip->can_sleep);
1159 return _gpiod_get_raw_value(desc);
1161 EXPORT_SYMBOL_GPL(gpiod_get_raw_value);
1164 * gpiod_get_value() - return a gpio's value
1165 * @desc: gpio whose value will be returned
1167 * Return the GPIO's logical value, i.e. taking the ACTIVE_LOW status into
1170 * This function should be called from contexts where we cannot sleep, and will
1171 * complain if the GPIO chip functions potentially sleep.
1173 int gpiod_get_value(const struct gpio_desc *desc)
1178 /* Should be using gpio_get_value_cansleep() */
1179 WARN_ON(desc->chip->can_sleep);
1181 value = _gpiod_get_raw_value(desc);
1182 if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
1187 EXPORT_SYMBOL_GPL(gpiod_get_value);
1190 * _gpio_set_open_drain_value() - Set the open drain gpio's value.
1191 * @desc: gpio descriptor whose state need to be set.
1192 * @value: Non-zero for setting it HIGH otherise it will set to LOW.
1194 static void _gpio_set_open_drain_value(struct gpio_desc *desc, bool value)
1197 struct gpio_chip *chip = desc->chip;
1198 int offset = gpio_chip_hwgpio(desc);
1201 err = chip->direction_input(chip, offset);
1203 clear_bit(FLAG_IS_OUT, &desc->flags);
1205 err = chip->direction_output(chip, offset, 0);
1207 set_bit(FLAG_IS_OUT, &desc->flags);
1209 trace_gpio_direction(desc_to_gpio(desc), value, err);
1212 "%s: Error in set_value for open drain err %d\n",
1217 * _gpio_set_open_source_value() - Set the open source gpio's value.
1218 * @desc: gpio descriptor whose state need to be set.
1219 * @value: Non-zero for setting it HIGH otherise it will set to LOW.
1221 static void _gpio_set_open_source_value(struct gpio_desc *desc, bool value)
1224 struct gpio_chip *chip = desc->chip;
1225 int offset = gpio_chip_hwgpio(desc);
1228 err = chip->direction_output(chip, offset, 1);
1230 set_bit(FLAG_IS_OUT, &desc->flags);
1232 err = chip->direction_input(chip, offset);
1234 clear_bit(FLAG_IS_OUT, &desc->flags);
1236 trace_gpio_direction(desc_to_gpio(desc), !value, err);
1239 "%s: Error in set_value for open source err %d\n",
1243 static void _gpiod_set_raw_value(struct gpio_desc *desc, bool value)
1245 struct gpio_chip *chip;
1248 trace_gpio_value(desc_to_gpio(desc), 0, value);
1249 if (test_bit(FLAG_OPEN_DRAIN, &desc->flags))
1250 _gpio_set_open_drain_value(desc, value);
1251 else if (test_bit(FLAG_OPEN_SOURCE, &desc->flags))
1252 _gpio_set_open_source_value(desc, value);
1254 chip->set(chip, gpio_chip_hwgpio(desc), value);
1258 * gpiod_set_raw_value() - assign a gpio's raw value
1259 * @desc: gpio whose value will be assigned
1260 * @value: value to assign
1262 * Set the raw value of the GPIO, i.e. the value of its physical line without
1263 * regard for its ACTIVE_LOW status.
1265 * This function should be called from contexts where we cannot sleep, and will
1266 * complain if the GPIO chip functions potentially sleep.
1268 void gpiod_set_raw_value(struct gpio_desc *desc, int value)
1272 /* Should be using gpio_set_value_cansleep() */
1273 WARN_ON(desc->chip->can_sleep);
1274 _gpiod_set_raw_value(desc, value);
1276 EXPORT_SYMBOL_GPL(gpiod_set_raw_value);
1279 * gpiod_set_value() - assign a gpio's value
1280 * @desc: gpio whose value will be assigned
1281 * @value: value to assign
1283 * Set the logical value of the GPIO, i.e. taking its ACTIVE_LOW status into
1286 * This function should be called from contexts where we cannot sleep, and will
1287 * complain if the GPIO chip functions potentially sleep.
1289 void gpiod_set_value(struct gpio_desc *desc, int value)
1293 /* Should be using gpio_set_value_cansleep() */
1294 WARN_ON(desc->chip->can_sleep);
1295 if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
1297 _gpiod_set_raw_value(desc, value);
1299 EXPORT_SYMBOL_GPL(gpiod_set_value);
1302 * gpiod_cansleep() - report whether gpio value access may sleep
1303 * @desc: gpio to check
1306 int gpiod_cansleep(const struct gpio_desc *desc)
1310 return desc->chip->can_sleep;
1312 EXPORT_SYMBOL_GPL(gpiod_cansleep);
1315 * gpiod_to_irq() - return the IRQ corresponding to a GPIO
1316 * @desc: gpio whose IRQ will be returned (already requested)
1318 * Return the IRQ corresponding to the passed GPIO, or an error code in case of
1321 int gpiod_to_irq(const struct gpio_desc *desc)
1323 struct gpio_chip *chip;
1329 offset = gpio_chip_hwgpio(desc);
1330 return chip->to_irq ? chip->to_irq(chip, offset) : -ENXIO;
1332 EXPORT_SYMBOL_GPL(gpiod_to_irq);
1335 * gpio_lock_as_irq() - lock a GPIO to be used as IRQ
1336 * @chip: the chip the GPIO to lock belongs to
1337 * @offset: the offset of the GPIO to lock as IRQ
1339 * This is used directly by GPIO drivers that want to lock down
1340 * a certain GPIO line to be used for IRQs.
1342 int gpio_lock_as_irq(struct gpio_chip *chip, unsigned int offset)
1344 if (offset >= chip->ngpio)
1347 if (test_bit(FLAG_IS_OUT, &chip->desc[offset].flags)) {
1349 "%s: tried to flag a GPIO set as output for IRQ\n",
1354 set_bit(FLAG_USED_AS_IRQ, &chip->desc[offset].flags);
1357 EXPORT_SYMBOL_GPL(gpio_lock_as_irq);
1360 * gpio_unlock_as_irq() - unlock a GPIO used as IRQ
1361 * @chip: the chip the GPIO to lock belongs to
1362 * @offset: the offset of the GPIO to lock as IRQ
1364 * This is used directly by GPIO drivers that want to indicate
1365 * that a certain GPIO is no longer used exclusively for IRQ.
1367 void gpio_unlock_as_irq(struct gpio_chip *chip, unsigned int offset)
1369 if (offset >= chip->ngpio)
1372 clear_bit(FLAG_USED_AS_IRQ, &chip->desc[offset].flags);
1374 EXPORT_SYMBOL_GPL(gpio_unlock_as_irq);
1377 * gpiod_get_raw_value_cansleep() - return a gpio's raw value
1378 * @desc: gpio whose value will be returned
1380 * Return the GPIO's raw value, i.e. the value of the physical line disregarding
1381 * its ACTIVE_LOW status.
1383 * This function is to be called from contexts that can sleep.
1385 int gpiod_get_raw_value_cansleep(const struct gpio_desc *desc)
1387 might_sleep_if(extra_checks);
1390 return _gpiod_get_raw_value(desc);
1392 EXPORT_SYMBOL_GPL(gpiod_get_raw_value_cansleep);
1395 * gpiod_get_value_cansleep() - return a gpio's value
1396 * @desc: gpio whose value will be returned
1398 * Return the GPIO's logical value, i.e. taking the ACTIVE_LOW status into
1401 * This function is to be called from contexts that can sleep.
1403 int gpiod_get_value_cansleep(const struct gpio_desc *desc)
1407 might_sleep_if(extra_checks);
1411 value = _gpiod_get_raw_value(desc);
1412 if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
1417 EXPORT_SYMBOL_GPL(gpiod_get_value_cansleep);
1420 * gpiod_set_raw_value_cansleep() - assign a gpio's raw value
1421 * @desc: gpio whose value will be assigned
1422 * @value: value to assign
1424 * Set the raw value of the GPIO, i.e. the value of its physical line without
1425 * regard for its ACTIVE_LOW status.
1427 * This function is to be called from contexts that can sleep.
1429 void gpiod_set_raw_value_cansleep(struct gpio_desc *desc, int value)
1431 might_sleep_if(extra_checks);
1434 _gpiod_set_raw_value(desc, value);
1436 EXPORT_SYMBOL_GPL(gpiod_set_raw_value_cansleep);
1439 * gpiod_set_value_cansleep() - assign a gpio's value
1440 * @desc: gpio whose value will be assigned
1441 * @value: value to assign
1443 * Set the logical value of the GPIO, i.e. taking its ACTIVE_LOW status into
1446 * This function is to be called from contexts that can sleep.
1448 void gpiod_set_value_cansleep(struct gpio_desc *desc, int value)
1450 might_sleep_if(extra_checks);
1454 if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
1456 _gpiod_set_raw_value(desc, value);
1458 EXPORT_SYMBOL_GPL(gpiod_set_value_cansleep);
1461 * gpiod_add_lookup_table() - register GPIO device consumers
1462 * @table: table of consumers to register
1464 void gpiod_add_lookup_table(struct gpiod_lookup_table *table)
1466 mutex_lock(&gpio_lookup_lock);
1468 list_add_tail(&table->list, &gpio_lookup_list);
1470 mutex_unlock(&gpio_lookup_lock);
1473 static struct gpio_desc *of_find_gpio(struct device *dev, const char *con_id,
1475 enum gpio_lookup_flags *flags)
1477 static const char *suffixes[] = { "gpios", "gpio" };
1478 char prop_name[32]; /* 32 is max size of property name */
1479 enum of_gpio_flags of_flags;
1480 struct gpio_desc *desc;
1483 for (i = 0; i < ARRAY_SIZE(suffixes); i++) {
1485 snprintf(prop_name, 32, "%s-%s", con_id, suffixes[i]);
1487 snprintf(prop_name, 32, "%s", suffixes[i]);
1489 desc = of_get_named_gpiod_flags(dev->of_node, prop_name, idx,
1491 if (!IS_ERR(desc) || (PTR_ERR(desc) == -EPROBE_DEFER))
1498 if (of_flags & OF_GPIO_ACTIVE_LOW)
1499 *flags |= GPIO_ACTIVE_LOW;
1504 static struct gpio_desc *acpi_find_gpio(struct device *dev, const char *con_id,
1506 enum gpio_lookup_flags *flags)
1508 static const char * const suffixes[] = { "gpios", "gpio" };
1509 struct acpi_device *adev = ACPI_COMPANION(dev);
1510 struct acpi_gpio_info info;
1511 struct gpio_desc *desc;
1515 /* Try first from _DSD */
1516 for (i = 0; i < ARRAY_SIZE(suffixes); i++) {
1517 if (con_id && strcmp(con_id, "gpios")) {
1518 snprintf(propname, sizeof(propname), "%s-%s",
1519 con_id, suffixes[i]);
1521 snprintf(propname, sizeof(propname), "%s",
1525 desc = acpi_get_gpiod_by_index(adev, propname, idx, &info);
1526 if (!IS_ERR(desc) || (PTR_ERR(desc) == -EPROBE_DEFER))
1530 /* Then from plain _CRS GPIOs */
1532 desc = acpi_get_gpiod_by_index(adev, NULL, idx, &info);
1537 if (info.active_low)
1538 *flags |= GPIO_ACTIVE_LOW;
1543 static struct gpiod_lookup_table *gpiod_find_lookup_table(struct device *dev)
1545 const char *dev_id = dev ? dev_name(dev) : NULL;
1546 struct gpiod_lookup_table *table;
1548 mutex_lock(&gpio_lookup_lock);
1550 list_for_each_entry(table, &gpio_lookup_list, list) {
1551 if (table->dev_id && dev_id) {
1553 * Valid strings on both ends, must be identical to have
1556 if (!strcmp(table->dev_id, dev_id))
1560 * One of the pointers is NULL, so both must be to have
1563 if (dev_id == table->dev_id)
1570 mutex_unlock(&gpio_lookup_lock);
1574 static struct gpio_desc *gpiod_find(struct device *dev, const char *con_id,
1576 enum gpio_lookup_flags *flags)
1578 struct gpio_desc *desc = ERR_PTR(-ENOENT);
1579 struct gpiod_lookup_table *table;
1580 struct gpiod_lookup *p;
1582 table = gpiod_find_lookup_table(dev);
1586 for (p = &table->table[0]; p->chip_label; p++) {
1587 struct gpio_chip *chip;
1589 /* idx must always match exactly */
1593 /* If the lookup entry has a con_id, require exact match */
1594 if (p->con_id && (!con_id || strcmp(p->con_id, con_id)))
1597 chip = find_chip_by_name(p->chip_label);
1600 dev_err(dev, "cannot find GPIO chip %s\n",
1602 return ERR_PTR(-ENODEV);
1605 if (chip->ngpio <= p->chip_hwnum) {
1607 "requested GPIO %d is out of range [0..%d] for chip %s\n",
1608 idx, chip->ngpio, chip->label);
1609 return ERR_PTR(-EINVAL);
1612 desc = gpiochip_get_desc(chip, p->chip_hwnum);
1622 * gpiod_get - obtain a GPIO for a given GPIO function
1623 * @dev: GPIO consumer, can be NULL for system-global GPIOs
1624 * @con_id: function within the GPIO consumer
1625 * @flags: optional GPIO initialization flags
1627 * Return the GPIO descriptor corresponding to the function con_id of device
1628 * dev, -ENOENT if no GPIO has been assigned to the requested function, or
1629 * another IS_ERR() code if an error occured while trying to acquire the GPIO.
1631 struct gpio_desc *__must_check __gpiod_get(struct device *dev, const char *con_id,
1632 enum gpiod_flags flags)
1634 return gpiod_get_index(dev, con_id, 0, flags);
1636 EXPORT_SYMBOL_GPL(__gpiod_get);
1639 * gpiod_get_optional - obtain an optional GPIO for a given GPIO function
1640 * @dev: GPIO consumer, can be NULL for system-global GPIOs
1641 * @con_id: function within the GPIO consumer
1642 * @flags: optional GPIO initialization flags
1644 * This is equivalent to gpiod_get(), except that when no GPIO was assigned to
1645 * the requested function it will return NULL. This is convenient for drivers
1646 * that need to handle optional GPIOs.
1648 struct gpio_desc *__must_check __gpiod_get_optional(struct device *dev,
1650 enum gpiod_flags flags)
1652 return gpiod_get_index_optional(dev, con_id, 0, flags);
1654 EXPORT_SYMBOL_GPL(__gpiod_get_optional);
1657 * gpiod_get_index - obtain a GPIO from a multi-index GPIO function
1658 * @dev: GPIO consumer, can be NULL for system-global GPIOs
1659 * @con_id: function within the GPIO consumer
1660 * @idx: index of the GPIO to obtain in the consumer
1661 * @flags: optional GPIO initialization flags
1663 * This variant of gpiod_get() allows to access GPIOs other than the first
1664 * defined one for functions that define several GPIOs.
1666 * Return a valid GPIO descriptor, -ENOENT if no GPIO has been assigned to the
1667 * requested function and/or index, or another IS_ERR() code if an error
1668 * occured while trying to acquire the GPIO.
1670 struct gpio_desc *__must_check __gpiod_get_index(struct device *dev,
1673 enum gpiod_flags flags)
1675 struct gpio_desc *desc = NULL;
1677 enum gpio_lookup_flags lookupflags = 0;
1679 dev_dbg(dev, "GPIO lookup for consumer %s\n", con_id);
1681 /* Using device tree? */
1682 if (IS_ENABLED(CONFIG_OF) && dev && dev->of_node) {
1683 dev_dbg(dev, "using device tree for GPIO lookup\n");
1684 desc = of_find_gpio(dev, con_id, idx, &lookupflags);
1685 } else if (IS_ENABLED(CONFIG_ACPI) && dev && ACPI_HANDLE(dev)) {
1686 dev_dbg(dev, "using ACPI for GPIO lookup\n");
1687 desc = acpi_find_gpio(dev, con_id, idx, &lookupflags);
1691 * Either we are not using DT or ACPI, or their lookup did not return
1692 * a result. In that case, use platform lookup as a fallback.
1694 if (!desc || desc == ERR_PTR(-ENOENT)) {
1695 dev_dbg(dev, "using lookup tables for GPIO lookup\n");
1696 desc = gpiod_find(dev, con_id, idx, &lookupflags);
1700 dev_dbg(dev, "lookup for GPIO %s failed\n", con_id);
1704 status = gpiod_request(desc, con_id);
1707 return ERR_PTR(status);
1709 if (lookupflags & GPIO_ACTIVE_LOW)
1710 set_bit(FLAG_ACTIVE_LOW, &desc->flags);
1711 if (lookupflags & GPIO_OPEN_DRAIN)
1712 set_bit(FLAG_OPEN_DRAIN, &desc->flags);
1713 if (lookupflags & GPIO_OPEN_SOURCE)
1714 set_bit(FLAG_OPEN_SOURCE, &desc->flags);
1716 /* No particular flag request, return here... */
1717 if (!(flags & GPIOD_FLAGS_BIT_DIR_SET))
1721 if (flags & GPIOD_FLAGS_BIT_DIR_OUT)
1722 status = gpiod_direction_output(desc,
1723 flags & GPIOD_FLAGS_BIT_DIR_VAL);
1725 status = gpiod_direction_input(desc);
1728 dev_dbg(dev, "setup of GPIO %s failed\n", con_id);
1730 return ERR_PTR(status);
1735 EXPORT_SYMBOL_GPL(__gpiod_get_index);
1738 * fwnode_get_named_gpiod - obtain a GPIO from firmware node
1739 * @fwnode: handle of the firmware node
1740 * @propname: name of the firmware property representing the GPIO
1742 * This function can be used for drivers that get their configuration
1745 * Function properly finds the corresponding GPIO using whatever is the
1746 * underlying firmware interface and then makes sure that the GPIO
1747 * descriptor is requested before it is returned to the caller.
1749 * In case of error an ERR_PTR() is returned.
1751 struct gpio_desc *fwnode_get_named_gpiod(struct fwnode_handle *fwnode,
1752 const char *propname)
1754 struct gpio_desc *desc = ERR_PTR(-ENODEV);
1755 bool active_low = false;
1759 return ERR_PTR(-EINVAL);
1761 if (is_of_node(fwnode)) {
1762 enum of_gpio_flags flags;
1764 desc = of_get_named_gpiod_flags(of_node(fwnode), propname, 0,
1767 active_low = flags & OF_GPIO_ACTIVE_LOW;
1768 } else if (is_acpi_node(fwnode)) {
1769 struct acpi_gpio_info info;
1771 desc = acpi_get_gpiod_by_index(acpi_node(fwnode), propname, 0,
1774 active_low = info.active_low;
1780 ret = gpiod_request(desc, NULL);
1782 return ERR_PTR(ret);
1784 /* Only value flag can be set from both DT and ACPI is active_low */
1786 set_bit(FLAG_ACTIVE_LOW, &desc->flags);
1790 EXPORT_SYMBOL_GPL(fwnode_get_named_gpiod);
1793 * gpiod_get_index_optional - obtain an optional GPIO from a multi-index GPIO
1795 * @dev: GPIO consumer, can be NULL for system-global GPIOs
1796 * @con_id: function within the GPIO consumer
1797 * @index: index of the GPIO to obtain in the consumer
1798 * @flags: optional GPIO initialization flags
1800 * This is equivalent to gpiod_get_index(), except that when no GPIO with the
1801 * specified index was assigned to the requested function it will return NULL.
1802 * This is convenient for drivers that need to handle optional GPIOs.
1804 struct gpio_desc *__must_check __gpiod_get_index_optional(struct device *dev,
1807 enum gpiod_flags flags)
1809 struct gpio_desc *desc;
1811 desc = gpiod_get_index(dev, con_id, index, flags);
1813 if (PTR_ERR(desc) == -ENOENT)
1819 EXPORT_SYMBOL_GPL(__gpiod_get_index_optional);
1822 * gpiod_put - dispose of a GPIO descriptor
1823 * @desc: GPIO descriptor to dispose of
1825 * No descriptor can be used after gpiod_put() has been called on it.
1827 void gpiod_put(struct gpio_desc *desc)
1831 EXPORT_SYMBOL_GPL(gpiod_put);
1833 #ifdef CONFIG_DEBUG_FS
1835 static void gpiolib_dbg_show(struct seq_file *s, struct gpio_chip *chip)
1838 unsigned gpio = chip->base;
1839 struct gpio_desc *gdesc = &chip->desc[0];
1843 for (i = 0; i < chip->ngpio; i++, gpio++, gdesc++) {
1844 if (!test_bit(FLAG_REQUESTED, &gdesc->flags))
1847 gpiod_get_direction(gdesc);
1848 is_out = test_bit(FLAG_IS_OUT, &gdesc->flags);
1849 is_irq = test_bit(FLAG_USED_AS_IRQ, &gdesc->flags);
1850 seq_printf(s, " gpio-%-3d (%-20.20s) %s %s %s",
1852 is_out ? "out" : "in ",
1854 ? (chip->get(chip, i) ? "hi" : "lo")
1856 is_irq ? "IRQ" : " ");
1857 seq_printf(s, "\n");
1861 static void *gpiolib_seq_start(struct seq_file *s, loff_t *pos)
1863 unsigned long flags;
1864 struct gpio_chip *chip = NULL;
1865 loff_t index = *pos;
1869 spin_lock_irqsave(&gpio_lock, flags);
1870 list_for_each_entry(chip, &gpio_chips, list)
1872 spin_unlock_irqrestore(&gpio_lock, flags);
1875 spin_unlock_irqrestore(&gpio_lock, flags);
1880 static void *gpiolib_seq_next(struct seq_file *s, void *v, loff_t *pos)
1882 unsigned long flags;
1883 struct gpio_chip *chip = v;
1886 spin_lock_irqsave(&gpio_lock, flags);
1887 if (list_is_last(&chip->list, &gpio_chips))
1890 ret = list_entry(chip->list.next, struct gpio_chip, list);
1891 spin_unlock_irqrestore(&gpio_lock, flags);
1899 static void gpiolib_seq_stop(struct seq_file *s, void *v)
1903 static int gpiolib_seq_show(struct seq_file *s, void *v)
1905 struct gpio_chip *chip = v;
1908 seq_printf(s, "%sGPIOs %d-%d", (char *)s->private,
1909 chip->base, chip->base + chip->ngpio - 1);
1912 seq_printf(s, ", %s/%s", dev->bus ? dev->bus->name : "no-bus",
1915 seq_printf(s, ", %s", chip->label);
1916 if (chip->can_sleep)
1917 seq_printf(s, ", can sleep");
1918 seq_printf(s, ":\n");
1921 chip->dbg_show(s, chip);
1923 gpiolib_dbg_show(s, chip);
1928 static const struct seq_operations gpiolib_seq_ops = {
1929 .start = gpiolib_seq_start,
1930 .next = gpiolib_seq_next,
1931 .stop = gpiolib_seq_stop,
1932 .show = gpiolib_seq_show,
1935 static int gpiolib_open(struct inode *inode, struct file *file)
1937 return seq_open(file, &gpiolib_seq_ops);
1940 static const struct file_operations gpiolib_operations = {
1941 .owner = THIS_MODULE,
1942 .open = gpiolib_open,
1944 .llseek = seq_lseek,
1945 .release = seq_release,
1948 static int __init gpiolib_debugfs_init(void)
1950 /* /sys/kernel/debug/gpio */
1951 (void) debugfs_create_file("gpio", S_IFREG | S_IRUGO,
1952 NULL, NULL, &gpiolib_operations);
1955 subsys_initcall(gpiolib_debugfs_init);
1957 #endif /* DEBUG_FS */