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 #define GPIO_OFFSET_VALID(chip, offset) (offset >= 0 && offset < chip->ngpio)
52 static DEFINE_MUTEX(gpio_lookup_lock);
53 static LIST_HEAD(gpio_lookup_list);
54 LIST_HEAD(gpio_chips);
56 static inline void desc_set_label(struct gpio_desc *d, const char *label)
62 * Convert a GPIO number to its descriptor
64 struct gpio_desc *gpio_to_desc(unsigned gpio)
66 struct gpio_chip *chip;
69 spin_lock_irqsave(&gpio_lock, flags);
71 list_for_each_entry(chip, &gpio_chips, list) {
72 if (chip->base <= gpio && chip->base + chip->ngpio > gpio) {
73 spin_unlock_irqrestore(&gpio_lock, flags);
74 return &chip->desc[gpio - chip->base];
78 spin_unlock_irqrestore(&gpio_lock, flags);
80 if (!gpio_is_valid(gpio))
81 WARN(1, "invalid GPIO %d\n", gpio);
85 EXPORT_SYMBOL_GPL(gpio_to_desc);
88 * Get the GPIO descriptor corresponding to the given hw number for this chip.
90 struct gpio_desc *gpiochip_get_desc(struct gpio_chip *chip,
93 if (hwnum >= chip->ngpio)
94 return ERR_PTR(-EINVAL);
96 return &chip->desc[hwnum];
100 * Convert a GPIO descriptor to the integer namespace.
101 * This should disappear in the future but is needed since we still
102 * use GPIO numbers for error messages and sysfs nodes
104 int desc_to_gpio(const struct gpio_desc *desc)
106 return desc->chip->base + (desc - &desc->chip->desc[0]);
108 EXPORT_SYMBOL_GPL(desc_to_gpio);
112 * gpiod_to_chip - Return the GPIO chip to which a GPIO descriptor belongs
113 * @desc: descriptor to return the chip of
115 struct gpio_chip *gpiod_to_chip(const struct gpio_desc *desc)
117 return desc ? desc->chip : NULL;
119 EXPORT_SYMBOL_GPL(gpiod_to_chip);
121 /* dynamic allocation of GPIOs, e.g. on a hotplugged device */
122 static int gpiochip_find_base(int ngpio)
124 struct gpio_chip *chip;
125 int base = ARCH_NR_GPIOS - ngpio;
127 list_for_each_entry_reverse(chip, &gpio_chips, list) {
128 /* found a free space? */
129 if (chip->base + chip->ngpio <= base)
132 /* nope, check the space right before the chip */
133 base = chip->base - ngpio;
136 if (gpio_is_valid(base)) {
137 pr_debug("%s: found new base at %d\n", __func__, base);
140 pr_err("%s: cannot find free range\n", __func__);
146 * gpiod_get_direction - return the current direction of a GPIO
147 * @desc: GPIO to get the direction of
149 * Return GPIOF_DIR_IN or GPIOF_DIR_OUT, or an error code in case of error.
151 * This function may sleep if gpiod_cansleep() is true.
153 int gpiod_get_direction(struct gpio_desc *desc)
155 struct gpio_chip *chip;
157 int status = -EINVAL;
159 chip = gpiod_to_chip(desc);
160 offset = gpio_chip_hwgpio(desc);
162 if (!chip->get_direction)
165 status = chip->get_direction(chip, offset);
167 /* GPIOF_DIR_IN, or other positive */
169 clear_bit(FLAG_IS_OUT, &desc->flags);
173 set_bit(FLAG_IS_OUT, &desc->flags);
177 EXPORT_SYMBOL_GPL(gpiod_get_direction);
180 * Add a new chip to the global chips list, keeping the list of chips sorted
183 * Return -EBUSY if the new chip overlaps with some other chip's integer
186 static int gpiochip_add_to_list(struct gpio_chip *chip)
188 struct list_head *pos = &gpio_chips;
189 struct gpio_chip *_chip;
192 /* find where to insert our chip */
193 list_for_each(pos, &gpio_chips) {
194 _chip = list_entry(pos, struct gpio_chip, list);
195 /* shall we insert before _chip? */
196 if (_chip->base >= chip->base + chip->ngpio)
200 /* are we stepping on the chip right before? */
201 if (pos != &gpio_chips && pos->prev != &gpio_chips) {
202 _chip = list_entry(pos->prev, struct gpio_chip, list);
203 if (_chip->base + _chip->ngpio > chip->base) {
205 "GPIO integer space overlap, cannot add chip\n");
211 list_add_tail(&chip->list, pos);
217 * gpiochip_add() - register a gpio_chip
218 * @chip: the chip to register, with chip->base initialized
219 * Context: potentially before irqs will work
221 * Returns a negative errno if the chip can't be registered, such as
222 * because the chip->base is invalid or already associated with a
223 * different chip. Otherwise it returns zero as a success code.
225 * When gpiochip_add() is called very early during boot, so that GPIOs
226 * can be freely used, the chip->dev device must be registered before
227 * the gpio framework's arch_initcall(). Otherwise sysfs initialization
228 * for GPIOs will fail rudely.
230 * If chip->base is negative, this requests dynamic assignment of
231 * a range of valid GPIOs.
233 int gpiochip_add(struct gpio_chip *chip)
238 int base = chip->base;
239 struct gpio_desc *descs;
241 descs = kcalloc(chip->ngpio, sizeof(descs[0]), GFP_KERNEL);
245 spin_lock_irqsave(&gpio_lock, flags);
248 base = gpiochip_find_base(chip->ngpio);
251 spin_unlock_irqrestore(&gpio_lock, flags);
257 status = gpiochip_add_to_list(chip);
259 spin_unlock_irqrestore(&gpio_lock, flags);
263 for (id = 0; id < chip->ngpio; id++) {
264 struct gpio_desc *desc = &descs[id];
268 /* REVISIT: most hardware initializes GPIOs as inputs (often
269 * with pullups enabled) so power usage is minimized. Linux
270 * code should set the gpio direction first thing; but until
271 * it does, and in case chip->get_direction is not set, we may
272 * expose the wrong direction in sysfs.
274 desc->flags = !chip->direction_input ? (1 << FLAG_IS_OUT) : 0;
279 spin_unlock_irqrestore(&gpio_lock, flags);
281 #ifdef CONFIG_PINCTRL
282 INIT_LIST_HEAD(&chip->pin_ranges);
285 of_gpiochip_add(chip);
286 acpi_gpiochip_add(chip);
288 status = gpiochip_sysfs_register(chip);
290 goto err_remove_chip;
292 pr_debug("%s: registered GPIOs %d to %d on device: %s\n", __func__,
293 chip->base, chip->base + chip->ngpio - 1,
294 chip->label ? : "generic");
299 acpi_gpiochip_remove(chip);
300 of_gpiochip_remove(chip);
301 spin_lock_irqsave(&gpio_lock, flags);
302 list_del(&chip->list);
303 spin_unlock_irqrestore(&gpio_lock, flags);
308 /* failures here can mean systems won't boot... */
309 pr_err("%s: GPIOs %d..%d (%s) failed to register\n", __func__,
310 chip->base, chip->base + chip->ngpio - 1,
311 chip->label ? : "generic");
314 EXPORT_SYMBOL_GPL(gpiochip_add);
316 /* Forward-declaration */
317 static void gpiochip_irqchip_remove(struct gpio_chip *gpiochip);
318 static void gpiochip_free_hogs(struct gpio_chip *chip);
321 * gpiochip_remove() - unregister a gpio_chip
322 * @chip: the chip to unregister
324 * A gpio_chip with any GPIOs still requested may not be removed.
326 void gpiochip_remove(struct gpio_chip *chip)
328 struct gpio_desc *desc;
331 bool requested = false;
333 gpiochip_sysfs_unregister(chip);
335 gpiochip_irqchip_remove(chip);
337 acpi_gpiochip_remove(chip);
338 gpiochip_remove_pin_ranges(chip);
339 gpiochip_free_hogs(chip);
340 of_gpiochip_remove(chip);
342 spin_lock_irqsave(&gpio_lock, flags);
343 for (id = 0; id < chip->ngpio; id++) {
344 desc = &chip->desc[id];
346 if (test_bit(FLAG_REQUESTED, &desc->flags))
349 list_del(&chip->list);
350 spin_unlock_irqrestore(&gpio_lock, flags);
353 dev_crit(chip->dev, "REMOVING GPIOCHIP WITH GPIOS STILL REQUESTED\n");
358 EXPORT_SYMBOL_GPL(gpiochip_remove);
361 * gpiochip_find() - iterator for locating a specific gpio_chip
362 * @data: data to pass to match function
363 * @callback: Callback function to check gpio_chip
365 * Similar to bus_find_device. It returns a reference to a gpio_chip as
366 * determined by a user supplied @match callback. The callback should return
367 * 0 if the device doesn't match and non-zero if it does. If the callback is
368 * non-zero, this function will return to the caller and not iterate over any
371 struct gpio_chip *gpiochip_find(void *data,
372 int (*match)(struct gpio_chip *chip,
375 struct gpio_chip *chip;
378 spin_lock_irqsave(&gpio_lock, flags);
379 list_for_each_entry(chip, &gpio_chips, list)
380 if (match(chip, data))
384 if (&chip->list == &gpio_chips)
386 spin_unlock_irqrestore(&gpio_lock, flags);
390 EXPORT_SYMBOL_GPL(gpiochip_find);
392 static int gpiochip_match_name(struct gpio_chip *chip, void *data)
394 const char *name = data;
396 return !strcmp(chip->label, name);
399 static struct gpio_chip *find_chip_by_name(const char *name)
401 return gpiochip_find((void *)name, gpiochip_match_name);
404 #ifdef CONFIG_GPIOLIB_IRQCHIP
407 * The following is irqchip helper code for gpiochips.
411 * gpiochip_set_chained_irqchip() - sets a chained irqchip to a gpiochip
412 * @gpiochip: the gpiochip to set the irqchip chain to
413 * @irqchip: the irqchip to chain to the gpiochip
414 * @parent_irq: the irq number corresponding to the parent IRQ for this
416 * @parent_handler: the parent interrupt handler for the accumulated IRQ
417 * coming out of the gpiochip. If the interrupt is nested rather than
418 * cascaded, pass NULL in this handler argument
420 void gpiochip_set_chained_irqchip(struct gpio_chip *gpiochip,
421 struct irq_chip *irqchip,
423 irq_flow_handler_t parent_handler)
427 if (!gpiochip->irqdomain) {
428 chip_err(gpiochip, "called %s before setting up irqchip\n",
433 if (parent_handler) {
434 if (gpiochip->can_sleep) {
436 "you cannot have chained interrupts on a "
437 "chip that may sleep\n");
441 * The parent irqchip is already using the chip_data for this
442 * irqchip, so our callbacks simply use the handler_data.
444 irq_set_handler_data(parent_irq, gpiochip);
445 irq_set_chained_handler(parent_irq, parent_handler);
447 gpiochip->irq_parent = parent_irq;
450 /* Set the parent IRQ for all affected IRQs */
451 for (offset = 0; offset < gpiochip->ngpio; offset++)
452 irq_set_parent(irq_find_mapping(gpiochip->irqdomain, offset),
455 EXPORT_SYMBOL_GPL(gpiochip_set_chained_irqchip);
458 * This lock class tells lockdep that GPIO irqs are in a different
459 * category than their parents, so it won't report false recursion.
461 static struct lock_class_key gpiochip_irq_lock_class;
464 * gpiochip_irq_map() - maps an IRQ into a GPIO irqchip
465 * @d: the irqdomain used by this irqchip
466 * @irq: the global irq number used by this GPIO irqchip irq
467 * @hwirq: the local IRQ/GPIO line offset on this gpiochip
469 * This function will set up the mapping for a certain IRQ line on a
470 * gpiochip by assigning the gpiochip as chip data, and using the irqchip
471 * stored inside the gpiochip.
473 static int gpiochip_irq_map(struct irq_domain *d, unsigned int irq,
474 irq_hw_number_t hwirq)
476 struct gpio_chip *chip = d->host_data;
478 irq_set_chip_data(irq, chip);
479 irq_set_lockdep_class(irq, &gpiochip_irq_lock_class);
480 irq_set_chip_and_handler(irq, chip->irqchip, chip->irq_handler);
481 /* Chips that can sleep need nested thread handlers */
482 if (chip->can_sleep && !chip->irq_not_threaded)
483 irq_set_nested_thread(irq, 1);
485 set_irq_flags(irq, IRQF_VALID);
487 irq_set_noprobe(irq);
490 * No set-up of the hardware will happen if IRQ_TYPE_NONE
491 * is passed as default type.
493 if (chip->irq_default_type != IRQ_TYPE_NONE)
494 irq_set_irq_type(irq, chip->irq_default_type);
499 static void gpiochip_irq_unmap(struct irq_domain *d, unsigned int irq)
501 struct gpio_chip *chip = d->host_data;
504 set_irq_flags(irq, 0);
507 irq_set_nested_thread(irq, 0);
508 irq_set_chip_and_handler(irq, NULL, NULL);
509 irq_set_chip_data(irq, NULL);
512 static const struct irq_domain_ops gpiochip_domain_ops = {
513 .map = gpiochip_irq_map,
514 .unmap = gpiochip_irq_unmap,
515 /* Virtually all GPIO irqchips are twocell:ed */
516 .xlate = irq_domain_xlate_twocell,
519 static int gpiochip_irq_reqres(struct irq_data *d)
521 struct gpio_chip *chip = irq_data_get_irq_chip_data(d);
523 if (gpiochip_lock_as_irq(chip, d->hwirq)) {
525 "unable to lock HW IRQ %lu for IRQ\n",
532 static void gpiochip_irq_relres(struct irq_data *d)
534 struct gpio_chip *chip = irq_data_get_irq_chip_data(d);
536 gpiochip_unlock_as_irq(chip, d->hwirq);
539 static int gpiochip_to_irq(struct gpio_chip *chip, unsigned offset)
541 return irq_find_mapping(chip->irqdomain, offset);
545 * gpiochip_irqchip_remove() - removes an irqchip added to a gpiochip
546 * @gpiochip: the gpiochip to remove the irqchip from
548 * This is called only from gpiochip_remove()
550 static void gpiochip_irqchip_remove(struct gpio_chip *gpiochip)
554 acpi_gpiochip_free_interrupts(gpiochip);
556 if (gpiochip->irq_parent) {
557 irq_set_chained_handler(gpiochip->irq_parent, NULL);
558 irq_set_handler_data(gpiochip->irq_parent, NULL);
561 /* Remove all IRQ mappings and delete the domain */
562 if (gpiochip->irqdomain) {
563 for (offset = 0; offset < gpiochip->ngpio; offset++)
565 irq_find_mapping(gpiochip->irqdomain, offset));
566 irq_domain_remove(gpiochip->irqdomain);
569 if (gpiochip->irqchip) {
570 gpiochip->irqchip->irq_request_resources = NULL;
571 gpiochip->irqchip->irq_release_resources = NULL;
572 gpiochip->irqchip = NULL;
577 * gpiochip_irqchip_add() - adds an irqchip to a gpiochip
578 * @gpiochip: the gpiochip to add the irqchip to
579 * @irqchip: the irqchip to add to the gpiochip
580 * @first_irq: if not dynamically assigned, the base (first) IRQ to
581 * allocate gpiochip irqs from
582 * @handler: the irq handler to use (often a predefined irq core function)
583 * @type: the default type for IRQs on this irqchip, pass IRQ_TYPE_NONE
584 * to have the core avoid setting up any default type in the hardware.
586 * This function closely associates a certain irqchip with a certain
587 * gpiochip, providing an irq domain to translate the local IRQs to
588 * global irqs in the gpiolib core, and making sure that the gpiochip
589 * is passed as chip data to all related functions. Driver callbacks
590 * need to use container_of() to get their local state containers back
591 * from the gpiochip passed as chip data. An irqdomain will be stored
592 * in the gpiochip that shall be used by the driver to handle IRQ number
593 * translation. The gpiochip will need to be initialized and registered
594 * before calling this function.
596 * This function will handle two cell:ed simple IRQs and assumes all
597 * the pins on the gpiochip can generate a unique IRQ. Everything else
598 * need to be open coded.
600 int gpiochip_irqchip_add(struct gpio_chip *gpiochip,
601 struct irq_chip *irqchip,
602 unsigned int first_irq,
603 irq_flow_handler_t handler,
606 struct device_node *of_node;
608 unsigned irq_base = 0;
610 if (!gpiochip || !irqchip)
613 if (!gpiochip->dev) {
614 pr_err("missing gpiochip .dev parent pointer\n");
617 of_node = gpiochip->dev->of_node;
618 #ifdef CONFIG_OF_GPIO
620 * If the gpiochip has an assigned OF node this takes precedence
621 * FIXME: get rid of this and use gpiochip->dev->of_node everywhere
623 if (gpiochip->of_node)
624 of_node = gpiochip->of_node;
626 gpiochip->irqchip = irqchip;
627 gpiochip->irq_handler = handler;
628 gpiochip->irq_default_type = type;
629 gpiochip->to_irq = gpiochip_to_irq;
630 gpiochip->irqdomain = irq_domain_add_simple(of_node,
631 gpiochip->ngpio, first_irq,
632 &gpiochip_domain_ops, gpiochip);
633 if (!gpiochip->irqdomain) {
634 gpiochip->irqchip = NULL;
637 irqchip->irq_request_resources = gpiochip_irq_reqres;
638 irqchip->irq_release_resources = gpiochip_irq_relres;
641 * Prepare the mapping since the irqchip shall be orthogonal to
642 * any gpiochip calls. If the first_irq was zero, this is
643 * necessary to allocate descriptors for all IRQs.
645 for (offset = 0; offset < gpiochip->ngpio; offset++) {
646 irq_base = irq_create_mapping(gpiochip->irqdomain, offset);
649 * Store the base into the gpiochip to be used when
650 * unmapping the irqs.
652 gpiochip->irq_base = irq_base;
655 acpi_gpiochip_request_interrupts(gpiochip);
659 EXPORT_SYMBOL_GPL(gpiochip_irqchip_add);
661 #else /* CONFIG_GPIOLIB_IRQCHIP */
663 static void gpiochip_irqchip_remove(struct gpio_chip *gpiochip) {}
665 #endif /* CONFIG_GPIOLIB_IRQCHIP */
667 #ifdef CONFIG_PINCTRL
670 * gpiochip_add_pingroup_range() - add a range for GPIO <-> pin mapping
671 * @chip: the gpiochip to add the range for
672 * @pinctrl: the dev_name() of the pin controller to map to
673 * @gpio_offset: the start offset in the current gpio_chip number space
674 * @pin_group: name of the pin group inside the pin controller
676 int gpiochip_add_pingroup_range(struct gpio_chip *chip,
677 struct pinctrl_dev *pctldev,
678 unsigned int gpio_offset, const char *pin_group)
680 struct gpio_pin_range *pin_range;
683 pin_range = kzalloc(sizeof(*pin_range), GFP_KERNEL);
685 chip_err(chip, "failed to allocate pin ranges\n");
689 /* Use local offset as range ID */
690 pin_range->range.id = gpio_offset;
691 pin_range->range.gc = chip;
692 pin_range->range.name = chip->label;
693 pin_range->range.base = chip->base + gpio_offset;
694 pin_range->pctldev = pctldev;
696 ret = pinctrl_get_group_pins(pctldev, pin_group,
697 &pin_range->range.pins,
698 &pin_range->range.npins);
704 pinctrl_add_gpio_range(pctldev, &pin_range->range);
706 chip_dbg(chip, "created GPIO range %d->%d ==> %s PINGRP %s\n",
707 gpio_offset, gpio_offset + pin_range->range.npins - 1,
708 pinctrl_dev_get_devname(pctldev), pin_group);
710 list_add_tail(&pin_range->node, &chip->pin_ranges);
714 EXPORT_SYMBOL_GPL(gpiochip_add_pingroup_range);
717 * gpiochip_add_pin_range() - add a range for GPIO <-> pin mapping
718 * @chip: the gpiochip to add the range for
719 * @pinctrl_name: the dev_name() of the pin controller to map to
720 * @gpio_offset: the start offset in the current gpio_chip number space
721 * @pin_offset: the start offset in the pin controller number space
722 * @npins: the number of pins from the offset of each pin space (GPIO and
723 * pin controller) to accumulate in this range
725 int gpiochip_add_pin_range(struct gpio_chip *chip, const char *pinctl_name,
726 unsigned int gpio_offset, unsigned int pin_offset,
729 struct gpio_pin_range *pin_range;
732 pin_range = kzalloc(sizeof(*pin_range), GFP_KERNEL);
734 chip_err(chip, "failed to allocate pin ranges\n");
738 /* Use local offset as range ID */
739 pin_range->range.id = gpio_offset;
740 pin_range->range.gc = chip;
741 pin_range->range.name = chip->label;
742 pin_range->range.base = chip->base + gpio_offset;
743 pin_range->range.pin_base = pin_offset;
744 pin_range->range.npins = npins;
745 pin_range->pctldev = pinctrl_find_and_add_gpio_range(pinctl_name,
747 if (IS_ERR(pin_range->pctldev)) {
748 ret = PTR_ERR(pin_range->pctldev);
749 chip_err(chip, "could not create pin range\n");
753 chip_dbg(chip, "created GPIO range %d->%d ==> %s PIN %d->%d\n",
754 gpio_offset, gpio_offset + npins - 1,
756 pin_offset, pin_offset + npins - 1);
758 list_add_tail(&pin_range->node, &chip->pin_ranges);
762 EXPORT_SYMBOL_GPL(gpiochip_add_pin_range);
765 * gpiochip_remove_pin_ranges() - remove all the GPIO <-> pin mappings
766 * @chip: the chip to remove all the mappings for
768 void gpiochip_remove_pin_ranges(struct gpio_chip *chip)
770 struct gpio_pin_range *pin_range, *tmp;
772 list_for_each_entry_safe(pin_range, tmp, &chip->pin_ranges, node) {
773 list_del(&pin_range->node);
774 pinctrl_remove_gpio_range(pin_range->pctldev,
779 EXPORT_SYMBOL_GPL(gpiochip_remove_pin_ranges);
781 #endif /* CONFIG_PINCTRL */
783 /* These "optional" allocation calls help prevent drivers from stomping
784 * on each other, and help provide better diagnostics in debugfs.
785 * They're called even less than the "set direction" calls.
787 static int __gpiod_request(struct gpio_desc *desc, const char *label)
789 struct gpio_chip *chip = desc->chip;
793 spin_lock_irqsave(&gpio_lock, flags);
795 /* NOTE: gpio_request() can be called in early boot,
796 * before IRQs are enabled, for non-sleeping (SOC) GPIOs.
799 if (test_and_set_bit(FLAG_REQUESTED, &desc->flags) == 0) {
800 desc_set_label(desc, label ? : "?");
808 /* chip->request may sleep */
809 spin_unlock_irqrestore(&gpio_lock, flags);
810 status = chip->request(chip, gpio_chip_hwgpio(desc));
811 spin_lock_irqsave(&gpio_lock, flags);
814 desc_set_label(desc, NULL);
815 clear_bit(FLAG_REQUESTED, &desc->flags);
819 if (chip->get_direction) {
820 /* chip->get_direction may sleep */
821 spin_unlock_irqrestore(&gpio_lock, flags);
822 gpiod_get_direction(desc);
823 spin_lock_irqsave(&gpio_lock, flags);
826 spin_unlock_irqrestore(&gpio_lock, flags);
830 int gpiod_request(struct gpio_desc *desc, const char *label)
832 int status = -EPROBE_DEFER;
833 struct gpio_chip *chip;
836 pr_warn("%s: invalid GPIO\n", __func__);
844 if (try_module_get(chip->owner)) {
845 status = __gpiod_request(desc, label);
847 module_put(chip->owner);
852 gpiod_dbg(desc, "%s: status %d\n", __func__, status);
857 static bool __gpiod_free(struct gpio_desc *desc)
861 struct gpio_chip *chip;
865 gpiod_unexport(desc);
867 spin_lock_irqsave(&gpio_lock, flags);
870 if (chip && test_bit(FLAG_REQUESTED, &desc->flags)) {
872 spin_unlock_irqrestore(&gpio_lock, flags);
873 might_sleep_if(chip->can_sleep);
874 chip->free(chip, gpio_chip_hwgpio(desc));
875 spin_lock_irqsave(&gpio_lock, flags);
877 desc_set_label(desc, NULL);
878 clear_bit(FLAG_ACTIVE_LOW, &desc->flags);
879 clear_bit(FLAG_REQUESTED, &desc->flags);
880 clear_bit(FLAG_OPEN_DRAIN, &desc->flags);
881 clear_bit(FLAG_OPEN_SOURCE, &desc->flags);
882 clear_bit(FLAG_IS_HOGGED, &desc->flags);
886 spin_unlock_irqrestore(&gpio_lock, flags);
890 void gpiod_free(struct gpio_desc *desc)
892 if (desc && __gpiod_free(desc))
893 module_put(desc->chip->owner);
895 WARN_ON(extra_checks);
899 * gpiochip_is_requested - return string iff signal was requested
900 * @chip: controller managing the signal
901 * @offset: of signal within controller's 0..(ngpio - 1) range
903 * Returns NULL if the GPIO is not currently requested, else a string.
904 * The string returned is the label passed to gpio_request(); if none has been
905 * passed it is a meaningless, non-NULL constant.
907 * This function is for use by GPIO controller drivers. The label can
908 * help with diagnostics, and knowing that the signal is used as a GPIO
909 * can help avoid accidentally multiplexing it to another controller.
911 const char *gpiochip_is_requested(struct gpio_chip *chip, unsigned offset)
913 struct gpio_desc *desc;
915 if (!GPIO_OFFSET_VALID(chip, offset))
918 desc = &chip->desc[offset];
920 if (test_bit(FLAG_REQUESTED, &desc->flags) == 0)
924 EXPORT_SYMBOL_GPL(gpiochip_is_requested);
927 * gpiochip_request_own_desc - Allow GPIO chip to request its own descriptor
928 * @desc: GPIO descriptor to request
929 * @label: label for the GPIO
931 * Function allows GPIO chip drivers to request and use their own GPIO
932 * descriptors via gpiolib API. Difference to gpiod_request() is that this
933 * function will not increase reference count of the GPIO chip module. This
934 * allows the GPIO chip module to be unloaded as needed (we assume that the
935 * GPIO chip driver handles freeing the GPIOs it has requested).
937 struct gpio_desc *gpiochip_request_own_desc(struct gpio_chip *chip, u16 hwnum,
940 struct gpio_desc *desc = gpiochip_get_desc(chip, hwnum);
944 chip_err(chip, "failed to get GPIO descriptor\n");
948 err = __gpiod_request(desc, label);
954 EXPORT_SYMBOL_GPL(gpiochip_request_own_desc);
957 * gpiochip_free_own_desc - Free GPIO requested by the chip driver
958 * @desc: GPIO descriptor to free
960 * Function frees the given GPIO requested previously with
961 * gpiochip_request_own_desc().
963 void gpiochip_free_own_desc(struct gpio_desc *desc)
968 EXPORT_SYMBOL_GPL(gpiochip_free_own_desc);
970 /* Drivers MUST set GPIO direction before making get/set calls. In
971 * some cases this is done in early boot, before IRQs are enabled.
973 * As a rule these aren't called more than once (except for drivers
974 * using the open-drain emulation idiom) so these are natural places
975 * to accumulate extra debugging checks. Note that we can't (yet)
976 * rely on gpio_request() having been called beforehand.
980 * gpiod_direction_input - set the GPIO direction to input
981 * @desc: GPIO to set to input
983 * Set the direction of the passed GPIO to input, such as gpiod_get_value() can
984 * be called safely on it.
986 * Return 0 in case of success, else an error code.
988 int gpiod_direction_input(struct gpio_desc *desc)
990 struct gpio_chip *chip;
991 int status = -EINVAL;
993 if (!desc || !desc->chip) {
994 pr_warn("%s: invalid GPIO\n", __func__);
999 if (!chip->get || !chip->direction_input) {
1001 "%s: missing get() or direction_input() operations\n",
1006 status = chip->direction_input(chip, gpio_chip_hwgpio(desc));
1008 clear_bit(FLAG_IS_OUT, &desc->flags);
1010 trace_gpio_direction(desc_to_gpio(desc), 1, status);
1014 EXPORT_SYMBOL_GPL(gpiod_direction_input);
1016 static int _gpiod_direction_output_raw(struct gpio_desc *desc, int value)
1018 struct gpio_chip *chip;
1019 int status = -EINVAL;
1021 /* GPIOs used for IRQs shall not be set as output */
1022 if (test_bit(FLAG_USED_AS_IRQ, &desc->flags)) {
1024 "%s: tried to set a GPIO tied to an IRQ as output\n",
1029 /* Open drain pin should not be driven to 1 */
1030 if (value && test_bit(FLAG_OPEN_DRAIN, &desc->flags))
1031 return gpiod_direction_input(desc);
1033 /* Open source pin should not be driven to 0 */
1034 if (!value && test_bit(FLAG_OPEN_SOURCE, &desc->flags))
1035 return gpiod_direction_input(desc);
1038 if (!chip->set || !chip->direction_output) {
1040 "%s: missing set() or direction_output() operations\n",
1045 status = chip->direction_output(chip, gpio_chip_hwgpio(desc), value);
1047 set_bit(FLAG_IS_OUT, &desc->flags);
1048 trace_gpio_value(desc_to_gpio(desc), 0, value);
1049 trace_gpio_direction(desc_to_gpio(desc), 0, status);
1054 * gpiod_direction_output_raw - set the GPIO direction to output
1055 * @desc: GPIO to set to output
1056 * @value: initial output value of the GPIO
1058 * Set the direction of the passed GPIO to output, such as gpiod_set_value() can
1059 * be called safely on it. The initial value of the output must be specified
1060 * as raw value on the physical line without regard for the ACTIVE_LOW status.
1062 * Return 0 in case of success, else an error code.
1064 int gpiod_direction_output_raw(struct gpio_desc *desc, int value)
1066 if (!desc || !desc->chip) {
1067 pr_warn("%s: invalid GPIO\n", __func__);
1070 return _gpiod_direction_output_raw(desc, value);
1072 EXPORT_SYMBOL_GPL(gpiod_direction_output_raw);
1075 * gpiod_direction_output - set the GPIO direction to output
1076 * @desc: GPIO to set to output
1077 * @value: initial output value of the GPIO
1079 * Set the direction of the passed GPIO to output, such as gpiod_set_value() can
1080 * be called safely on it. The initial value of the output must be specified
1081 * as the logical value of the GPIO, i.e. taking its ACTIVE_LOW status into
1084 * Return 0 in case of success, else an error code.
1086 int gpiod_direction_output(struct gpio_desc *desc, int value)
1088 if (!desc || !desc->chip) {
1089 pr_warn("%s: invalid GPIO\n", __func__);
1092 if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
1094 return _gpiod_direction_output_raw(desc, value);
1096 EXPORT_SYMBOL_GPL(gpiod_direction_output);
1099 * gpiod_set_debounce - sets @debounce time for a @gpio
1100 * @gpio: the gpio to set debounce time
1101 * @debounce: debounce time is microseconds
1103 * returns -ENOTSUPP if the controller does not support setting
1106 int gpiod_set_debounce(struct gpio_desc *desc, unsigned debounce)
1108 struct gpio_chip *chip;
1110 if (!desc || !desc->chip) {
1111 pr_warn("%s: invalid GPIO\n", __func__);
1116 if (!chip->set || !chip->set_debounce) {
1118 "%s: missing set() or set_debounce() operations\n",
1123 return chip->set_debounce(chip, gpio_chip_hwgpio(desc), debounce);
1125 EXPORT_SYMBOL_GPL(gpiod_set_debounce);
1128 * gpiod_is_active_low - test whether a GPIO is active-low or not
1129 * @desc: the gpio descriptor to test
1131 * Returns 1 if the GPIO is active-low, 0 otherwise.
1133 int gpiod_is_active_low(const struct gpio_desc *desc)
1135 return test_bit(FLAG_ACTIVE_LOW, &desc->flags);
1137 EXPORT_SYMBOL_GPL(gpiod_is_active_low);
1139 /* I/O calls are only valid after configuration completed; the relevant
1140 * "is this a valid GPIO" error checks should already have been done.
1142 * "Get" operations are often inlinable as reading a pin value register,
1143 * and masking the relevant bit in that register.
1145 * When "set" operations are inlinable, they involve writing that mask to
1146 * one register to set a low value, or a different register to set it high.
1147 * Otherwise locking is needed, so there may be little value to inlining.
1149 *------------------------------------------------------------------------
1151 * IMPORTANT!!! The hot paths -- get/set value -- assume that callers
1152 * have requested the GPIO. That can include implicit requesting by
1153 * a direction setting call. Marking a gpio as requested locks its chip
1154 * in memory, guaranteeing that these table lookups need no more locking
1155 * and that gpiochip_remove() will fail.
1157 * REVISIT when debugging, consider adding some instrumentation to ensure
1158 * that the GPIO was actually requested.
1161 static bool _gpiod_get_raw_value(const struct gpio_desc *desc)
1163 struct gpio_chip *chip;
1168 offset = gpio_chip_hwgpio(desc);
1169 value = chip->get ? chip->get(chip, offset) : false;
1170 trace_gpio_value(desc_to_gpio(desc), 1, value);
1175 * gpiod_get_raw_value() - return a gpio's raw value
1176 * @desc: gpio whose value will be returned
1178 * Return the GPIO's raw value, i.e. the value of the physical line disregarding
1179 * its ACTIVE_LOW status.
1181 * This function should be called from contexts where we cannot sleep, and will
1182 * complain if the GPIO chip functions potentially sleep.
1184 int gpiod_get_raw_value(const struct gpio_desc *desc)
1188 /* Should be using gpio_get_value_cansleep() */
1189 WARN_ON(desc->chip->can_sleep);
1190 return _gpiod_get_raw_value(desc);
1192 EXPORT_SYMBOL_GPL(gpiod_get_raw_value);
1195 * gpiod_get_value() - return a gpio's value
1196 * @desc: gpio whose value will be returned
1198 * Return the GPIO's logical value, i.e. taking the ACTIVE_LOW status into
1201 * This function should be called from contexts where we cannot sleep, and will
1202 * complain if the GPIO chip functions potentially sleep.
1204 int gpiod_get_value(const struct gpio_desc *desc)
1209 /* Should be using gpio_get_value_cansleep() */
1210 WARN_ON(desc->chip->can_sleep);
1212 value = _gpiod_get_raw_value(desc);
1213 if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
1218 EXPORT_SYMBOL_GPL(gpiod_get_value);
1221 * _gpio_set_open_drain_value() - Set the open drain gpio's value.
1222 * @desc: gpio descriptor whose state need to be set.
1223 * @value: Non-zero for setting it HIGH otherwise it will set to LOW.
1225 static void _gpio_set_open_drain_value(struct gpio_desc *desc, bool value)
1228 struct gpio_chip *chip = desc->chip;
1229 int offset = gpio_chip_hwgpio(desc);
1232 err = chip->direction_input(chip, offset);
1234 clear_bit(FLAG_IS_OUT, &desc->flags);
1236 err = chip->direction_output(chip, offset, 0);
1238 set_bit(FLAG_IS_OUT, &desc->flags);
1240 trace_gpio_direction(desc_to_gpio(desc), value, err);
1243 "%s: Error in set_value for open drain err %d\n",
1248 * _gpio_set_open_source_value() - Set the open source gpio's value.
1249 * @desc: gpio descriptor whose state need to be set.
1250 * @value: Non-zero for setting it HIGH otherwise it will set to LOW.
1252 static void _gpio_set_open_source_value(struct gpio_desc *desc, bool value)
1255 struct gpio_chip *chip = desc->chip;
1256 int offset = gpio_chip_hwgpio(desc);
1259 err = chip->direction_output(chip, offset, 1);
1261 set_bit(FLAG_IS_OUT, &desc->flags);
1263 err = chip->direction_input(chip, offset);
1265 clear_bit(FLAG_IS_OUT, &desc->flags);
1267 trace_gpio_direction(desc_to_gpio(desc), !value, err);
1270 "%s: Error in set_value for open source err %d\n",
1274 static void _gpiod_set_raw_value(struct gpio_desc *desc, bool value)
1276 struct gpio_chip *chip;
1279 trace_gpio_value(desc_to_gpio(desc), 0, value);
1280 if (test_bit(FLAG_OPEN_DRAIN, &desc->flags))
1281 _gpio_set_open_drain_value(desc, value);
1282 else if (test_bit(FLAG_OPEN_SOURCE, &desc->flags))
1283 _gpio_set_open_source_value(desc, value);
1285 chip->set(chip, gpio_chip_hwgpio(desc), value);
1289 * set multiple outputs on the same chip;
1290 * use the chip's set_multiple function if available;
1291 * otherwise set the outputs sequentially;
1292 * @mask: bit mask array; one bit per output; BITS_PER_LONG bits per word
1293 * defines which outputs are to be changed
1294 * @bits: bit value array; one bit per output; BITS_PER_LONG bits per word
1295 * defines the values the outputs specified by mask are to be set to
1297 static void gpio_chip_set_multiple(struct gpio_chip *chip,
1298 unsigned long *mask, unsigned long *bits)
1300 if (chip->set_multiple) {
1301 chip->set_multiple(chip, mask, bits);
1304 for (i = 0; i < chip->ngpio; i++) {
1305 if (mask[BIT_WORD(i)] == 0) {
1306 /* no more set bits in this mask word;
1307 * skip ahead to the next word */
1308 i = (BIT_WORD(i) + 1) * BITS_PER_LONG - 1;
1311 /* set outputs if the corresponding mask bit is set */
1312 if (__test_and_clear_bit(i, mask))
1313 chip->set(chip, i, test_bit(i, bits));
1318 static void gpiod_set_array_value_priv(bool raw, bool can_sleep,
1319 unsigned int array_size,
1320 struct gpio_desc **desc_array,
1325 while (i < array_size) {
1326 struct gpio_chip *chip = desc_array[i]->chip;
1327 unsigned long mask[BITS_TO_LONGS(chip->ngpio)];
1328 unsigned long bits[BITS_TO_LONGS(chip->ngpio)];
1332 WARN_ON(chip->can_sleep);
1334 memset(mask, 0, sizeof(mask));
1336 struct gpio_desc *desc = desc_array[i];
1337 int hwgpio = gpio_chip_hwgpio(desc);
1338 int value = value_array[i];
1340 if (!raw && test_bit(FLAG_ACTIVE_LOW, &desc->flags))
1342 trace_gpio_value(desc_to_gpio(desc), 0, value);
1344 * collect all normal outputs belonging to the same chip
1345 * open drain and open source outputs are set individually
1347 if (test_bit(FLAG_OPEN_DRAIN, &desc->flags)) {
1348 _gpio_set_open_drain_value(desc, value);
1349 } else if (test_bit(FLAG_OPEN_SOURCE, &desc->flags)) {
1350 _gpio_set_open_source_value(desc, value);
1352 __set_bit(hwgpio, mask);
1354 __set_bit(hwgpio, bits);
1356 __clear_bit(hwgpio, bits);
1360 } while ((i < array_size) && (desc_array[i]->chip == chip));
1361 /* push collected bits to outputs */
1363 gpio_chip_set_multiple(chip, mask, bits);
1368 * gpiod_set_raw_value() - assign a gpio's raw value
1369 * @desc: gpio whose value will be assigned
1370 * @value: value to assign
1372 * Set the raw value of the GPIO, i.e. the value of its physical line without
1373 * regard for its ACTIVE_LOW status.
1375 * This function should be called from contexts where we cannot sleep, and will
1376 * complain if the GPIO chip functions potentially sleep.
1378 void gpiod_set_raw_value(struct gpio_desc *desc, int value)
1382 /* Should be using gpio_set_value_cansleep() */
1383 WARN_ON(desc->chip->can_sleep);
1384 _gpiod_set_raw_value(desc, value);
1386 EXPORT_SYMBOL_GPL(gpiod_set_raw_value);
1389 * gpiod_set_value() - assign a gpio's value
1390 * @desc: gpio whose value will be assigned
1391 * @value: value to assign
1393 * Set the logical value of the GPIO, i.e. taking its ACTIVE_LOW status into
1396 * This function should be called from contexts where we cannot sleep, and will
1397 * complain if the GPIO chip functions potentially sleep.
1399 void gpiod_set_value(struct gpio_desc *desc, int value)
1403 /* Should be using gpio_set_value_cansleep() */
1404 WARN_ON(desc->chip->can_sleep);
1405 if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
1407 _gpiod_set_raw_value(desc, value);
1409 EXPORT_SYMBOL_GPL(gpiod_set_value);
1412 * gpiod_set_raw_array_value() - assign values to an array of GPIOs
1413 * @array_size: number of elements in the descriptor / value arrays
1414 * @desc_array: array of GPIO descriptors whose values will be assigned
1415 * @value_array: array of values to assign
1417 * Set the raw values of the GPIOs, i.e. the values of the physical lines
1418 * without regard for their ACTIVE_LOW status.
1420 * This function should be called from contexts where we cannot sleep, and will
1421 * complain if the GPIO chip functions potentially sleep.
1423 void gpiod_set_raw_array_value(unsigned int array_size,
1424 struct gpio_desc **desc_array, int *value_array)
1428 gpiod_set_array_value_priv(true, false, array_size, desc_array,
1431 EXPORT_SYMBOL_GPL(gpiod_set_raw_array_value);
1434 * gpiod_set_array_value() - assign values to an array of GPIOs
1435 * @array_size: number of elements in the descriptor / value arrays
1436 * @desc_array: array of GPIO descriptors whose values will be assigned
1437 * @value_array: array of values to assign
1439 * Set the logical values of the GPIOs, i.e. taking their ACTIVE_LOW status
1442 * This function should be called from contexts where we cannot sleep, and will
1443 * complain if the GPIO chip functions potentially sleep.
1445 void gpiod_set_array_value(unsigned int array_size,
1446 struct gpio_desc **desc_array, int *value_array)
1450 gpiod_set_array_value_priv(false, false, array_size, desc_array,
1453 EXPORT_SYMBOL_GPL(gpiod_set_array_value);
1456 * gpiod_cansleep() - report whether gpio value access may sleep
1457 * @desc: gpio to check
1460 int gpiod_cansleep(const struct gpio_desc *desc)
1464 return desc->chip->can_sleep;
1466 EXPORT_SYMBOL_GPL(gpiod_cansleep);
1469 * gpiod_to_irq() - return the IRQ corresponding to a GPIO
1470 * @desc: gpio whose IRQ will be returned (already requested)
1472 * Return the IRQ corresponding to the passed GPIO, or an error code in case of
1475 int gpiod_to_irq(const struct gpio_desc *desc)
1477 struct gpio_chip *chip;
1483 offset = gpio_chip_hwgpio(desc);
1484 return chip->to_irq ? chip->to_irq(chip, offset) : -ENXIO;
1486 EXPORT_SYMBOL_GPL(gpiod_to_irq);
1489 * gpiochip_lock_as_irq() - lock a GPIO to be used as IRQ
1490 * @chip: the chip the GPIO to lock belongs to
1491 * @offset: the offset of the GPIO to lock as IRQ
1493 * This is used directly by GPIO drivers that want to lock down
1494 * a certain GPIO line to be used for IRQs.
1496 int gpiochip_lock_as_irq(struct gpio_chip *chip, unsigned int offset)
1498 if (offset >= chip->ngpio)
1501 if (test_bit(FLAG_IS_OUT, &chip->desc[offset].flags)) {
1503 "%s: tried to flag a GPIO set as output for IRQ\n",
1508 set_bit(FLAG_USED_AS_IRQ, &chip->desc[offset].flags);
1511 EXPORT_SYMBOL_GPL(gpiochip_lock_as_irq);
1514 * gpiochip_unlock_as_irq() - unlock a GPIO used as IRQ
1515 * @chip: the chip the GPIO to lock belongs to
1516 * @offset: the offset of the GPIO to lock as IRQ
1518 * This is used directly by GPIO drivers that want to indicate
1519 * that a certain GPIO is no longer used exclusively for IRQ.
1521 void gpiochip_unlock_as_irq(struct gpio_chip *chip, unsigned int offset)
1523 if (offset >= chip->ngpio)
1526 clear_bit(FLAG_USED_AS_IRQ, &chip->desc[offset].flags);
1528 EXPORT_SYMBOL_GPL(gpiochip_unlock_as_irq);
1531 * gpiod_get_raw_value_cansleep() - return a gpio's raw value
1532 * @desc: gpio whose value will be returned
1534 * Return the GPIO's raw value, i.e. the value of the physical line disregarding
1535 * its ACTIVE_LOW status.
1537 * This function is to be called from contexts that can sleep.
1539 int gpiod_get_raw_value_cansleep(const struct gpio_desc *desc)
1541 might_sleep_if(extra_checks);
1544 return _gpiod_get_raw_value(desc);
1546 EXPORT_SYMBOL_GPL(gpiod_get_raw_value_cansleep);
1549 * gpiod_get_value_cansleep() - return a gpio's value
1550 * @desc: gpio whose value will be returned
1552 * Return the GPIO's logical value, i.e. taking the ACTIVE_LOW status into
1555 * This function is to be called from contexts that can sleep.
1557 int gpiod_get_value_cansleep(const struct gpio_desc *desc)
1561 might_sleep_if(extra_checks);
1565 value = _gpiod_get_raw_value(desc);
1566 if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
1571 EXPORT_SYMBOL_GPL(gpiod_get_value_cansleep);
1574 * gpiod_set_raw_value_cansleep() - assign a gpio's raw value
1575 * @desc: gpio whose value will be assigned
1576 * @value: value to assign
1578 * Set the raw value of the GPIO, i.e. the value of its physical line without
1579 * regard for its ACTIVE_LOW status.
1581 * This function is to be called from contexts that can sleep.
1583 void gpiod_set_raw_value_cansleep(struct gpio_desc *desc, int value)
1585 might_sleep_if(extra_checks);
1588 _gpiod_set_raw_value(desc, value);
1590 EXPORT_SYMBOL_GPL(gpiod_set_raw_value_cansleep);
1593 * gpiod_set_value_cansleep() - assign a gpio's value
1594 * @desc: gpio whose value will be assigned
1595 * @value: value to assign
1597 * Set the logical value of the GPIO, i.e. taking its ACTIVE_LOW status into
1600 * This function is to be called from contexts that can sleep.
1602 void gpiod_set_value_cansleep(struct gpio_desc *desc, int value)
1604 might_sleep_if(extra_checks);
1608 if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
1610 _gpiod_set_raw_value(desc, value);
1612 EXPORT_SYMBOL_GPL(gpiod_set_value_cansleep);
1615 * gpiod_set_raw_array_value_cansleep() - assign values to an array of GPIOs
1616 * @array_size: number of elements in the descriptor / value arrays
1617 * @desc_array: array of GPIO descriptors whose values will be assigned
1618 * @value_array: array of values to assign
1620 * Set the raw values of the GPIOs, i.e. the values of the physical lines
1621 * without regard for their ACTIVE_LOW status.
1623 * This function is to be called from contexts that can sleep.
1625 void gpiod_set_raw_array_value_cansleep(unsigned int array_size,
1626 struct gpio_desc **desc_array,
1629 might_sleep_if(extra_checks);
1632 gpiod_set_array_value_priv(true, true, array_size, desc_array,
1635 EXPORT_SYMBOL_GPL(gpiod_set_raw_array_value_cansleep);
1638 * gpiod_set_array_value_cansleep() - assign values to an array of GPIOs
1639 * @array_size: number of elements in the descriptor / value arrays
1640 * @desc_array: array of GPIO descriptors whose values will be assigned
1641 * @value_array: array of values to assign
1643 * Set the logical values of the GPIOs, i.e. taking their ACTIVE_LOW status
1646 * This function is to be called from contexts that can sleep.
1648 void gpiod_set_array_value_cansleep(unsigned int array_size,
1649 struct gpio_desc **desc_array,
1652 might_sleep_if(extra_checks);
1655 gpiod_set_array_value_priv(false, true, array_size, desc_array,
1658 EXPORT_SYMBOL_GPL(gpiod_set_array_value_cansleep);
1661 * gpiod_add_lookup_table() - register GPIO device consumers
1662 * @table: table of consumers to register
1664 void gpiod_add_lookup_table(struct gpiod_lookup_table *table)
1666 mutex_lock(&gpio_lookup_lock);
1668 list_add_tail(&table->list, &gpio_lookup_list);
1670 mutex_unlock(&gpio_lookup_lock);
1673 static struct gpio_desc *of_find_gpio(struct device *dev, const char *con_id,
1675 enum gpio_lookup_flags *flags)
1677 char prop_name[32]; /* 32 is max size of property name */
1678 enum of_gpio_flags of_flags;
1679 struct gpio_desc *desc;
1682 for (i = 0; i < ARRAY_SIZE(gpio_suffixes); i++) {
1684 snprintf(prop_name, sizeof(prop_name), "%s-%s", con_id,
1687 snprintf(prop_name, sizeof(prop_name), "%s",
1690 desc = of_get_named_gpiod_flags(dev->of_node, prop_name, idx,
1692 if (!IS_ERR(desc) || (PTR_ERR(desc) == -EPROBE_DEFER))
1699 if (of_flags & OF_GPIO_ACTIVE_LOW)
1700 *flags |= GPIO_ACTIVE_LOW;
1705 static struct gpio_desc *acpi_find_gpio(struct device *dev, const char *con_id,
1707 enum gpio_lookup_flags *flags)
1709 struct acpi_device *adev = ACPI_COMPANION(dev);
1710 struct acpi_gpio_info info;
1711 struct gpio_desc *desc;
1715 /* Try first from _DSD */
1716 for (i = 0; i < ARRAY_SIZE(gpio_suffixes); i++) {
1717 if (con_id && strcmp(con_id, "gpios")) {
1718 snprintf(propname, sizeof(propname), "%s-%s",
1719 con_id, gpio_suffixes[i]);
1721 snprintf(propname, sizeof(propname), "%s",
1725 desc = acpi_get_gpiod_by_index(adev, propname, idx, &info);
1726 if (!IS_ERR(desc) || (PTR_ERR(desc) == -EPROBE_DEFER))
1730 /* Then from plain _CRS GPIOs */
1732 desc = acpi_get_gpiod_by_index(adev, NULL, idx, &info);
1737 if (info.active_low)
1738 *flags |= GPIO_ACTIVE_LOW;
1743 static struct gpiod_lookup_table *gpiod_find_lookup_table(struct device *dev)
1745 const char *dev_id = dev ? dev_name(dev) : NULL;
1746 struct gpiod_lookup_table *table;
1748 mutex_lock(&gpio_lookup_lock);
1750 list_for_each_entry(table, &gpio_lookup_list, list) {
1751 if (table->dev_id && dev_id) {
1753 * Valid strings on both ends, must be identical to have
1756 if (!strcmp(table->dev_id, dev_id))
1760 * One of the pointers is NULL, so both must be to have
1763 if (dev_id == table->dev_id)
1770 mutex_unlock(&gpio_lookup_lock);
1774 static struct gpio_desc *gpiod_find(struct device *dev, const char *con_id,
1776 enum gpio_lookup_flags *flags)
1778 struct gpio_desc *desc = ERR_PTR(-ENOENT);
1779 struct gpiod_lookup_table *table;
1780 struct gpiod_lookup *p;
1782 table = gpiod_find_lookup_table(dev);
1786 for (p = &table->table[0]; p->chip_label; p++) {
1787 struct gpio_chip *chip;
1789 /* idx must always match exactly */
1793 /* If the lookup entry has a con_id, require exact match */
1794 if (p->con_id && (!con_id || strcmp(p->con_id, con_id)))
1797 chip = find_chip_by_name(p->chip_label);
1800 dev_err(dev, "cannot find GPIO chip %s\n",
1802 return ERR_PTR(-ENODEV);
1805 if (chip->ngpio <= p->chip_hwnum) {
1807 "requested GPIO %d is out of range [0..%d] for chip %s\n",
1808 idx, chip->ngpio, chip->label);
1809 return ERR_PTR(-EINVAL);
1812 desc = gpiochip_get_desc(chip, p->chip_hwnum);
1821 static int dt_gpio_count(struct device *dev, const char *con_id)
1827 for (i = 0; i < ARRAY_SIZE(gpio_suffixes); i++) {
1829 snprintf(propname, sizeof(propname), "%s-%s",
1830 con_id, gpio_suffixes[i]);
1832 snprintf(propname, sizeof(propname), "%s",
1835 ret = of_gpio_named_count(dev->of_node, propname);
1842 static int platform_gpio_count(struct device *dev, const char *con_id)
1844 struct gpiod_lookup_table *table;
1845 struct gpiod_lookup *p;
1846 unsigned int count = 0;
1848 table = gpiod_find_lookup_table(dev);
1852 for (p = &table->table[0]; p->chip_label; p++) {
1853 if ((con_id && p->con_id && !strcmp(con_id, p->con_id)) ||
1854 (!con_id && !p->con_id))
1864 * gpiod_count - return the number of GPIOs associated with a device / function
1865 * or -ENOENT if no GPIO has been assigned to the requested function
1866 * @dev: GPIO consumer, can be NULL for system-global GPIOs
1867 * @con_id: function within the GPIO consumer
1869 int gpiod_count(struct device *dev, const char *con_id)
1871 int count = -ENOENT;
1873 if (IS_ENABLED(CONFIG_OF) && dev && dev->of_node)
1874 count = dt_gpio_count(dev, con_id);
1875 else if (IS_ENABLED(CONFIG_ACPI) && dev && ACPI_HANDLE(dev))
1876 count = acpi_gpio_count(dev, con_id);
1879 count = platform_gpio_count(dev, con_id);
1883 EXPORT_SYMBOL_GPL(gpiod_count);
1886 * gpiod_get - obtain a GPIO for a given GPIO function
1887 * @dev: GPIO consumer, can be NULL for system-global GPIOs
1888 * @con_id: function within the GPIO consumer
1889 * @flags: optional GPIO initialization flags
1891 * Return the GPIO descriptor corresponding to the function con_id of device
1892 * dev, -ENOENT if no GPIO has been assigned to the requested function, or
1893 * another IS_ERR() code if an error occurred while trying to acquire the GPIO.
1895 struct gpio_desc *__must_check __gpiod_get(struct device *dev, const char *con_id,
1896 enum gpiod_flags flags)
1898 return gpiod_get_index(dev, con_id, 0, flags);
1900 EXPORT_SYMBOL_GPL(__gpiod_get);
1903 * gpiod_get_optional - obtain an optional GPIO for a given GPIO function
1904 * @dev: GPIO consumer, can be NULL for system-global GPIOs
1905 * @con_id: function within the GPIO consumer
1906 * @flags: optional GPIO initialization flags
1908 * This is equivalent to gpiod_get(), except that when no GPIO was assigned to
1909 * the requested function it will return NULL. This is convenient for drivers
1910 * that need to handle optional GPIOs.
1912 struct gpio_desc *__must_check __gpiod_get_optional(struct device *dev,
1914 enum gpiod_flags flags)
1916 return gpiod_get_index_optional(dev, con_id, 0, flags);
1918 EXPORT_SYMBOL_GPL(__gpiod_get_optional);
1922 * gpiod_configure_flags - helper function to configure a given GPIO
1923 * @desc: gpio whose value will be assigned
1924 * @con_id: function within the GPIO consumer
1925 * @lflags: gpio_lookup_flags - returned from of_find_gpio() or
1927 * @dflags: gpiod_flags - optional GPIO initialization flags
1929 * Return 0 on success, -ENOENT if no GPIO has been assigned to the
1930 * requested function and/or index, or another IS_ERR() code if an error
1931 * occurred while trying to acquire the GPIO.
1933 static int gpiod_configure_flags(struct gpio_desc *desc, const char *con_id,
1934 unsigned long lflags, enum gpiod_flags dflags)
1938 if (lflags & GPIO_ACTIVE_LOW)
1939 set_bit(FLAG_ACTIVE_LOW, &desc->flags);
1940 if (lflags & GPIO_OPEN_DRAIN)
1941 set_bit(FLAG_OPEN_DRAIN, &desc->flags);
1942 if (lflags & GPIO_OPEN_SOURCE)
1943 set_bit(FLAG_OPEN_SOURCE, &desc->flags);
1945 /* No particular flag request, return here... */
1946 if (!(dflags & GPIOD_FLAGS_BIT_DIR_SET)) {
1947 pr_debug("no flags found for %s\n", con_id);
1952 if (dflags & GPIOD_FLAGS_BIT_DIR_OUT)
1953 status = gpiod_direction_output(desc,
1954 dflags & GPIOD_FLAGS_BIT_DIR_VAL);
1956 status = gpiod_direction_input(desc);
1962 * gpiod_get_index - obtain a GPIO from a multi-index GPIO function
1963 * @dev: GPIO consumer, can be NULL for system-global GPIOs
1964 * @con_id: function within the GPIO consumer
1965 * @idx: index of the GPIO to obtain in the consumer
1966 * @flags: optional GPIO initialization flags
1968 * This variant of gpiod_get() allows to access GPIOs other than the first
1969 * defined one for functions that define several GPIOs.
1971 * Return a valid GPIO descriptor, -ENOENT if no GPIO has been assigned to the
1972 * requested function and/or index, or another IS_ERR() code if an error
1973 * occurred while trying to acquire the GPIO.
1975 struct gpio_desc *__must_check __gpiod_get_index(struct device *dev,
1978 enum gpiod_flags flags)
1980 struct gpio_desc *desc = NULL;
1982 enum gpio_lookup_flags lookupflags = 0;
1984 dev_dbg(dev, "GPIO lookup for consumer %s\n", con_id);
1987 /* Using device tree? */
1988 if (IS_ENABLED(CONFIG_OF) && dev->of_node) {
1989 dev_dbg(dev, "using device tree for GPIO lookup\n");
1990 desc = of_find_gpio(dev, con_id, idx, &lookupflags);
1991 } else if (ACPI_COMPANION(dev)) {
1992 dev_dbg(dev, "using ACPI for GPIO lookup\n");
1993 desc = acpi_find_gpio(dev, con_id, idx, &lookupflags);
1998 * Either we are not using DT or ACPI, or their lookup did not return
1999 * a result. In that case, use platform lookup as a fallback.
2001 if (!desc || desc == ERR_PTR(-ENOENT)) {
2002 dev_dbg(dev, "using lookup tables for GPIO lookup\n");
2003 desc = gpiod_find(dev, con_id, idx, &lookupflags);
2007 dev_dbg(dev, "lookup for GPIO %s failed\n", con_id);
2011 status = gpiod_request(desc, con_id);
2013 return ERR_PTR(status);
2015 status = gpiod_configure_flags(desc, con_id, lookupflags, flags);
2017 dev_dbg(dev, "setup of GPIO %s failed\n", con_id);
2019 return ERR_PTR(status);
2024 EXPORT_SYMBOL_GPL(__gpiod_get_index);
2027 * fwnode_get_named_gpiod - obtain a GPIO from firmware node
2028 * @fwnode: handle of the firmware node
2029 * @propname: name of the firmware property representing the GPIO
2031 * This function can be used for drivers that get their configuration
2034 * Function properly finds the corresponding GPIO using whatever is the
2035 * underlying firmware interface and then makes sure that the GPIO
2036 * descriptor is requested before it is returned to the caller.
2038 * In case of error an ERR_PTR() is returned.
2040 struct gpio_desc *fwnode_get_named_gpiod(struct fwnode_handle *fwnode,
2041 const char *propname)
2043 struct gpio_desc *desc = ERR_PTR(-ENODEV);
2044 bool active_low = false;
2048 return ERR_PTR(-EINVAL);
2050 if (is_of_node(fwnode)) {
2051 enum of_gpio_flags flags;
2053 desc = of_get_named_gpiod_flags(of_node(fwnode), propname, 0,
2056 active_low = flags & OF_GPIO_ACTIVE_LOW;
2057 } else if (is_acpi_node(fwnode)) {
2058 struct acpi_gpio_info info;
2060 desc = acpi_get_gpiod_by_index(acpi_node(fwnode), propname, 0,
2063 active_low = info.active_low;
2069 ret = gpiod_request(desc, NULL);
2071 return ERR_PTR(ret);
2073 /* Only value flag can be set from both DT and ACPI is active_low */
2075 set_bit(FLAG_ACTIVE_LOW, &desc->flags);
2079 EXPORT_SYMBOL_GPL(fwnode_get_named_gpiod);
2082 * gpiod_get_index_optional - obtain an optional GPIO from a multi-index GPIO
2084 * @dev: GPIO consumer, can be NULL for system-global GPIOs
2085 * @con_id: function within the GPIO consumer
2086 * @index: index of the GPIO to obtain in the consumer
2087 * @flags: optional GPIO initialization flags
2089 * This is equivalent to gpiod_get_index(), except that when no GPIO with the
2090 * specified index was assigned to the requested function it will return NULL.
2091 * This is convenient for drivers that need to handle optional GPIOs.
2093 struct gpio_desc *__must_check __gpiod_get_index_optional(struct device *dev,
2096 enum gpiod_flags flags)
2098 struct gpio_desc *desc;
2100 desc = gpiod_get_index(dev, con_id, index, flags);
2102 if (PTR_ERR(desc) == -ENOENT)
2108 EXPORT_SYMBOL_GPL(__gpiod_get_index_optional);
2111 * gpiod_hog - Hog the specified GPIO desc given the provided flags
2112 * @desc: gpio whose value will be assigned
2113 * @name: gpio line name
2114 * @lflags: gpio_lookup_flags - returned from of_find_gpio() or
2116 * @dflags: gpiod_flags - optional GPIO initialization flags
2118 int gpiod_hog(struct gpio_desc *desc, const char *name,
2119 unsigned long lflags, enum gpiod_flags dflags)
2121 struct gpio_chip *chip;
2122 struct gpio_desc *local_desc;
2126 chip = gpiod_to_chip(desc);
2127 hwnum = gpio_chip_hwgpio(desc);
2129 local_desc = gpiochip_request_own_desc(chip, hwnum, name);
2130 if (IS_ERR(local_desc)) {
2131 pr_err("requesting hog GPIO %s (chip %s, offset %d) failed\n",
2132 name, chip->label, hwnum);
2133 return PTR_ERR(local_desc);
2136 status = gpiod_configure_flags(desc, name, lflags, dflags);
2138 pr_err("setup of hog GPIO %s (chip %s, offset %d) failed\n",
2139 name, chip->label, hwnum);
2140 gpiochip_free_own_desc(desc);
2144 /* Mark GPIO as hogged so it can be identified and removed later */
2145 set_bit(FLAG_IS_HOGGED, &desc->flags);
2147 pr_info("GPIO line %d (%s) hogged as %s%s\n",
2148 desc_to_gpio(desc), name,
2149 (dflags&GPIOD_FLAGS_BIT_DIR_OUT) ? "output" : "input",
2150 (dflags&GPIOD_FLAGS_BIT_DIR_OUT) ?
2151 (dflags&GPIOD_FLAGS_BIT_DIR_VAL) ? "/high" : "/low":"");
2157 * gpiochip_free_hogs - Scan gpio-controller chip and release GPIO hog
2158 * @chip: gpio chip to act on
2160 * This is only used by of_gpiochip_remove to free hogged gpios
2162 static void gpiochip_free_hogs(struct gpio_chip *chip)
2166 for (id = 0; id < chip->ngpio; id++) {
2167 if (test_bit(FLAG_IS_HOGGED, &chip->desc[id].flags))
2168 gpiochip_free_own_desc(&chip->desc[id]);
2173 * gpiod_get_array - obtain multiple GPIOs from a multi-index GPIO function
2174 * @dev: GPIO consumer, can be NULL for system-global GPIOs
2175 * @con_id: function within the GPIO consumer
2176 * @flags: optional GPIO initialization flags
2178 * This function acquires all the GPIOs defined under a given function.
2180 * Return a struct gpio_descs containing an array of descriptors, -ENOENT if
2181 * no GPIO has been assigned to the requested function, or another IS_ERR()
2182 * code if an error occurred while trying to acquire the GPIOs.
2184 struct gpio_descs *__must_check gpiod_get_array(struct device *dev,
2186 enum gpiod_flags flags)
2188 struct gpio_desc *desc;
2189 struct gpio_descs *descs;
2192 count = gpiod_count(dev, con_id);
2194 return ERR_PTR(count);
2196 descs = kzalloc(sizeof(*descs) + sizeof(descs->desc[0]) * count,
2199 return ERR_PTR(-ENOMEM);
2201 for (descs->ndescs = 0; descs->ndescs < count; ) {
2202 desc = gpiod_get_index(dev, con_id, descs->ndescs, flags);
2204 gpiod_put_array(descs);
2205 return ERR_CAST(desc);
2207 descs->desc[descs->ndescs] = desc;
2212 EXPORT_SYMBOL_GPL(gpiod_get_array);
2215 * gpiod_get_array_optional - obtain multiple GPIOs from a multi-index GPIO
2217 * @dev: GPIO consumer, can be NULL for system-global GPIOs
2218 * @con_id: function within the GPIO consumer
2219 * @flags: optional GPIO initialization flags
2221 * This is equivalent to gpiod_get_array(), except that when no GPIO was
2222 * assigned to the requested function it will return NULL.
2224 struct gpio_descs *__must_check gpiod_get_array_optional(struct device *dev,
2226 enum gpiod_flags flags)
2228 struct gpio_descs *descs;
2230 descs = gpiod_get_array(dev, con_id, flags);
2231 if (IS_ERR(descs) && (PTR_ERR(descs) == -ENOENT))
2236 EXPORT_SYMBOL_GPL(gpiod_get_array_optional);
2239 * gpiod_put - dispose of a GPIO descriptor
2240 * @desc: GPIO descriptor to dispose of
2242 * No descriptor can be used after gpiod_put() has been called on it.
2244 void gpiod_put(struct gpio_desc *desc)
2248 EXPORT_SYMBOL_GPL(gpiod_put);
2251 * gpiod_put_array - dispose of multiple GPIO descriptors
2252 * @descs: struct gpio_descs containing an array of descriptors
2254 void gpiod_put_array(struct gpio_descs *descs)
2258 for (i = 0; i < descs->ndescs; i++)
2259 gpiod_put(descs->desc[i]);
2263 EXPORT_SYMBOL_GPL(gpiod_put_array);
2265 #ifdef CONFIG_DEBUG_FS
2267 static void gpiolib_dbg_show(struct seq_file *s, struct gpio_chip *chip)
2270 unsigned gpio = chip->base;
2271 struct gpio_desc *gdesc = &chip->desc[0];
2275 for (i = 0; i < chip->ngpio; i++, gpio++, gdesc++) {
2276 if (!test_bit(FLAG_REQUESTED, &gdesc->flags))
2279 gpiod_get_direction(gdesc);
2280 is_out = test_bit(FLAG_IS_OUT, &gdesc->flags);
2281 is_irq = test_bit(FLAG_USED_AS_IRQ, &gdesc->flags);
2282 seq_printf(s, " gpio-%-3d (%-20.20s) %s %s %s",
2284 is_out ? "out" : "in ",
2286 ? (chip->get(chip, i) ? "hi" : "lo")
2288 is_irq ? "IRQ" : " ");
2289 seq_printf(s, "\n");
2293 static void *gpiolib_seq_start(struct seq_file *s, loff_t *pos)
2295 unsigned long flags;
2296 struct gpio_chip *chip = NULL;
2297 loff_t index = *pos;
2301 spin_lock_irqsave(&gpio_lock, flags);
2302 list_for_each_entry(chip, &gpio_chips, list)
2304 spin_unlock_irqrestore(&gpio_lock, flags);
2307 spin_unlock_irqrestore(&gpio_lock, flags);
2312 static void *gpiolib_seq_next(struct seq_file *s, void *v, loff_t *pos)
2314 unsigned long flags;
2315 struct gpio_chip *chip = v;
2318 spin_lock_irqsave(&gpio_lock, flags);
2319 if (list_is_last(&chip->list, &gpio_chips))
2322 ret = list_entry(chip->list.next, struct gpio_chip, list);
2323 spin_unlock_irqrestore(&gpio_lock, flags);
2331 static void gpiolib_seq_stop(struct seq_file *s, void *v)
2335 static int gpiolib_seq_show(struct seq_file *s, void *v)
2337 struct gpio_chip *chip = v;
2340 seq_printf(s, "%sGPIOs %d-%d", (char *)s->private,
2341 chip->base, chip->base + chip->ngpio - 1);
2344 seq_printf(s, ", %s/%s", dev->bus ? dev->bus->name : "no-bus",
2347 seq_printf(s, ", %s", chip->label);
2348 if (chip->can_sleep)
2349 seq_printf(s, ", can sleep");
2350 seq_printf(s, ":\n");
2353 chip->dbg_show(s, chip);
2355 gpiolib_dbg_show(s, chip);
2360 static const struct seq_operations gpiolib_seq_ops = {
2361 .start = gpiolib_seq_start,
2362 .next = gpiolib_seq_next,
2363 .stop = gpiolib_seq_stop,
2364 .show = gpiolib_seq_show,
2367 static int gpiolib_open(struct inode *inode, struct file *file)
2369 return seq_open(file, &gpiolib_seq_ops);
2372 static const struct file_operations gpiolib_operations = {
2373 .owner = THIS_MODULE,
2374 .open = gpiolib_open,
2376 .llseek = seq_lseek,
2377 .release = seq_release,
2380 static int __init gpiolib_debugfs_init(void)
2382 /* /sys/kernel/debug/gpio */
2383 (void) debugfs_create_file("gpio", S_IFREG | S_IRUGO,
2384 NULL, NULL, &gpiolib_operations);
2387 subsys_initcall(gpiolib_debugfs_init);
2389 #endif /* DEBUG_FS */