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_export(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);
320 * gpiochip_remove() - unregister a gpio_chip
321 * @chip: the chip to unregister
323 * A gpio_chip with any GPIOs still requested may not be removed.
325 void gpiochip_remove(struct gpio_chip *chip)
330 gpiochip_unexport(chip);
332 gpiochip_irqchip_remove(chip);
334 acpi_gpiochip_remove(chip);
335 gpiochip_remove_pin_ranges(chip);
336 of_gpiochip_remove(chip);
338 spin_lock_irqsave(&gpio_lock, flags);
339 for (id = 0; id < chip->ngpio; id++) {
340 if (test_bit(FLAG_REQUESTED, &chip->desc[id].flags))
341 dev_crit(chip->dev, "REMOVING GPIOCHIP WITH GPIOS STILL REQUESTED\n");
343 for (id = 0; id < chip->ngpio; id++)
344 chip->desc[id].chip = NULL;
346 list_del(&chip->list);
347 spin_unlock_irqrestore(&gpio_lock, flags);
352 EXPORT_SYMBOL_GPL(gpiochip_remove);
355 * gpiochip_find() - iterator for locating a specific gpio_chip
356 * @data: data to pass to match function
357 * @callback: Callback function to check gpio_chip
359 * Similar to bus_find_device. It returns a reference to a gpio_chip as
360 * determined by a user supplied @match callback. The callback should return
361 * 0 if the device doesn't match and non-zero if it does. If the callback is
362 * non-zero, this function will return to the caller and not iterate over any
365 struct gpio_chip *gpiochip_find(void *data,
366 int (*match)(struct gpio_chip *chip,
369 struct gpio_chip *chip;
372 spin_lock_irqsave(&gpio_lock, flags);
373 list_for_each_entry(chip, &gpio_chips, list)
374 if (match(chip, data))
378 if (&chip->list == &gpio_chips)
380 spin_unlock_irqrestore(&gpio_lock, flags);
384 EXPORT_SYMBOL_GPL(gpiochip_find);
386 static int gpiochip_match_name(struct gpio_chip *chip, void *data)
388 const char *name = data;
390 return !strcmp(chip->label, name);
393 static struct gpio_chip *find_chip_by_name(const char *name)
395 return gpiochip_find((void *)name, gpiochip_match_name);
398 #ifdef CONFIG_GPIOLIB_IRQCHIP
401 * The following is irqchip helper code for gpiochips.
405 * gpiochip_set_chained_irqchip() - sets a chained irqchip to a gpiochip
406 * @gpiochip: the gpiochip to set the irqchip chain to
407 * @irqchip: the irqchip to chain to the gpiochip
408 * @parent_irq: the irq number corresponding to the parent IRQ for this
410 * @parent_handler: the parent interrupt handler for the accumulated IRQ
411 * coming out of the gpiochip. If the interrupt is nested rather than
412 * cascaded, pass NULL in this handler argument
414 void gpiochip_set_chained_irqchip(struct gpio_chip *gpiochip,
415 struct irq_chip *irqchip,
417 irq_flow_handler_t parent_handler)
421 if (!gpiochip->irqdomain) {
422 chip_err(gpiochip, "called %s before setting up irqchip\n",
427 if (parent_handler) {
428 if (gpiochip->can_sleep) {
430 "you cannot have chained interrupts on a "
431 "chip that may sleep\n");
435 * The parent irqchip is already using the chip_data for this
436 * irqchip, so our callbacks simply use the handler_data.
438 irq_set_handler_data(parent_irq, gpiochip);
439 irq_set_chained_handler(parent_irq, parent_handler);
442 /* Set the parent IRQ for all affected IRQs */
443 for (offset = 0; offset < gpiochip->ngpio; offset++)
444 irq_set_parent(irq_find_mapping(gpiochip->irqdomain, offset),
447 EXPORT_SYMBOL_GPL(gpiochip_set_chained_irqchip);
450 * This lock class tells lockdep that GPIO irqs are in a different
451 * category than their parents, so it won't report false recursion.
453 static struct lock_class_key gpiochip_irq_lock_class;
456 * gpiochip_irq_map() - maps an IRQ into a GPIO irqchip
457 * @d: the irqdomain used by this irqchip
458 * @irq: the global irq number used by this GPIO irqchip irq
459 * @hwirq: the local IRQ/GPIO line offset on this gpiochip
461 * This function will set up the mapping for a certain IRQ line on a
462 * gpiochip by assigning the gpiochip as chip data, and using the irqchip
463 * stored inside the gpiochip.
465 static int gpiochip_irq_map(struct irq_domain *d, unsigned int irq,
466 irq_hw_number_t hwirq)
468 struct gpio_chip *chip = d->host_data;
470 irq_set_chip_data(irq, chip);
471 irq_set_lockdep_class(irq, &gpiochip_irq_lock_class);
472 irq_set_chip_and_handler(irq, chip->irqchip, chip->irq_handler);
473 /* Chips that can sleep need nested thread handlers */
474 if (chip->can_sleep && !chip->irq_not_threaded)
475 irq_set_nested_thread(irq, 1);
477 set_irq_flags(irq, IRQF_VALID);
479 irq_set_noprobe(irq);
482 * No set-up of the hardware will happen if IRQ_TYPE_NONE
483 * is passed as default type.
485 if (chip->irq_default_type != IRQ_TYPE_NONE)
486 irq_set_irq_type(irq, chip->irq_default_type);
491 static void gpiochip_irq_unmap(struct irq_domain *d, unsigned int irq)
493 struct gpio_chip *chip = d->host_data;
496 set_irq_flags(irq, 0);
499 irq_set_nested_thread(irq, 0);
500 irq_set_chip_and_handler(irq, NULL, NULL);
501 irq_set_chip_data(irq, NULL);
504 static const struct irq_domain_ops gpiochip_domain_ops = {
505 .map = gpiochip_irq_map,
506 .unmap = gpiochip_irq_unmap,
507 /* Virtually all GPIO irqchips are twocell:ed */
508 .xlate = irq_domain_xlate_twocell,
511 static int gpiochip_irq_reqres(struct irq_data *d)
513 struct gpio_chip *chip = irq_data_get_irq_chip_data(d);
515 if (gpiochip_lock_as_irq(chip, d->hwirq)) {
517 "unable to lock HW IRQ %lu for IRQ\n",
524 static void gpiochip_irq_relres(struct irq_data *d)
526 struct gpio_chip *chip = irq_data_get_irq_chip_data(d);
528 gpiochip_unlock_as_irq(chip, d->hwirq);
531 static int gpiochip_to_irq(struct gpio_chip *chip, unsigned offset)
533 return irq_find_mapping(chip->irqdomain, offset);
537 * gpiochip_irqchip_remove() - removes an irqchip added to a gpiochip
538 * @gpiochip: the gpiochip to remove the irqchip from
540 * This is called only from gpiochip_remove()
542 static void gpiochip_irqchip_remove(struct gpio_chip *gpiochip)
546 acpi_gpiochip_free_interrupts(gpiochip);
548 /* Remove all IRQ mappings and delete the domain */
549 if (gpiochip->irqdomain) {
550 for (offset = 0; offset < gpiochip->ngpio; offset++)
552 irq_find_mapping(gpiochip->irqdomain, offset));
553 irq_domain_remove(gpiochip->irqdomain);
556 if (gpiochip->irqchip) {
557 gpiochip->irqchip->irq_request_resources = NULL;
558 gpiochip->irqchip->irq_release_resources = NULL;
559 gpiochip->irqchip = NULL;
564 * gpiochip_irqchip_add() - adds an irqchip to a gpiochip
565 * @gpiochip: the gpiochip to add the irqchip to
566 * @irqchip: the irqchip to add to the gpiochip
567 * @first_irq: if not dynamically assigned, the base (first) IRQ to
568 * allocate gpiochip irqs from
569 * @handler: the irq handler to use (often a predefined irq core function)
570 * @type: the default type for IRQs on this irqchip, pass IRQ_TYPE_NONE
571 * to have the core avoid setting up any default type in the hardware.
573 * This function closely associates a certain irqchip with a certain
574 * gpiochip, providing an irq domain to translate the local IRQs to
575 * global irqs in the gpiolib core, and making sure that the gpiochip
576 * is passed as chip data to all related functions. Driver callbacks
577 * need to use container_of() to get their local state containers back
578 * from the gpiochip passed as chip data. An irqdomain will be stored
579 * in the gpiochip that shall be used by the driver to handle IRQ number
580 * translation. The gpiochip will need to be initialized and registered
581 * before calling this function.
583 * This function will handle two cell:ed simple IRQs and assumes all
584 * the pins on the gpiochip can generate a unique IRQ. Everything else
585 * need to be open coded.
587 int gpiochip_irqchip_add(struct gpio_chip *gpiochip,
588 struct irq_chip *irqchip,
589 unsigned int first_irq,
590 irq_flow_handler_t handler,
593 struct device_node *of_node;
595 unsigned irq_base = 0;
597 if (!gpiochip || !irqchip)
600 if (!gpiochip->dev) {
601 pr_err("missing gpiochip .dev parent pointer\n");
604 of_node = gpiochip->dev->of_node;
605 #ifdef CONFIG_OF_GPIO
607 * If the gpiochip has an assigned OF node this takes precendence
608 * FIXME: get rid of this and use gpiochip->dev->of_node everywhere
610 if (gpiochip->of_node)
611 of_node = gpiochip->of_node;
613 gpiochip->irqchip = irqchip;
614 gpiochip->irq_handler = handler;
615 gpiochip->irq_default_type = type;
616 gpiochip->to_irq = gpiochip_to_irq;
617 gpiochip->irqdomain = irq_domain_add_simple(of_node,
618 gpiochip->ngpio, first_irq,
619 &gpiochip_domain_ops, gpiochip);
620 if (!gpiochip->irqdomain) {
621 gpiochip->irqchip = NULL;
624 irqchip->irq_request_resources = gpiochip_irq_reqres;
625 irqchip->irq_release_resources = gpiochip_irq_relres;
628 * Prepare the mapping since the irqchip shall be orthogonal to
629 * any gpiochip calls. If the first_irq was zero, this is
630 * necessary to allocate descriptors for all IRQs.
632 for (offset = 0; offset < gpiochip->ngpio; offset++) {
633 irq_base = irq_create_mapping(gpiochip->irqdomain, offset);
636 * Store the base into the gpiochip to be used when
637 * unmapping the irqs.
639 gpiochip->irq_base = irq_base;
642 acpi_gpiochip_request_interrupts(gpiochip);
646 EXPORT_SYMBOL_GPL(gpiochip_irqchip_add);
648 #else /* CONFIG_GPIOLIB_IRQCHIP */
650 static void gpiochip_irqchip_remove(struct gpio_chip *gpiochip) {}
652 #endif /* CONFIG_GPIOLIB_IRQCHIP */
654 #ifdef CONFIG_PINCTRL
657 * gpiochip_add_pingroup_range() - add a range for GPIO <-> pin mapping
658 * @chip: the gpiochip to add the range for
659 * @pinctrl: the dev_name() of the pin controller to map to
660 * @gpio_offset: the start offset in the current gpio_chip number space
661 * @pin_group: name of the pin group inside the pin controller
663 int gpiochip_add_pingroup_range(struct gpio_chip *chip,
664 struct pinctrl_dev *pctldev,
665 unsigned int gpio_offset, const char *pin_group)
667 struct gpio_pin_range *pin_range;
670 pin_range = kzalloc(sizeof(*pin_range), GFP_KERNEL);
672 chip_err(chip, "failed to allocate pin ranges\n");
676 /* Use local offset as range ID */
677 pin_range->range.id = gpio_offset;
678 pin_range->range.gc = chip;
679 pin_range->range.name = chip->label;
680 pin_range->range.base = chip->base + gpio_offset;
681 pin_range->pctldev = pctldev;
683 ret = pinctrl_get_group_pins(pctldev, pin_group,
684 &pin_range->range.pins,
685 &pin_range->range.npins);
691 pinctrl_add_gpio_range(pctldev, &pin_range->range);
693 chip_dbg(chip, "created GPIO range %d->%d ==> %s PINGRP %s\n",
694 gpio_offset, gpio_offset + pin_range->range.npins - 1,
695 pinctrl_dev_get_devname(pctldev), pin_group);
697 list_add_tail(&pin_range->node, &chip->pin_ranges);
701 EXPORT_SYMBOL_GPL(gpiochip_add_pingroup_range);
704 * gpiochip_add_pin_range() - add a range for GPIO <-> pin mapping
705 * @chip: the gpiochip to add the range for
706 * @pinctrl_name: the dev_name() of the pin controller to map to
707 * @gpio_offset: the start offset in the current gpio_chip number space
708 * @pin_offset: the start offset in the pin controller number space
709 * @npins: the number of pins from the offset of each pin space (GPIO and
710 * pin controller) to accumulate in this range
712 int gpiochip_add_pin_range(struct gpio_chip *chip, const char *pinctl_name,
713 unsigned int gpio_offset, unsigned int pin_offset,
716 struct gpio_pin_range *pin_range;
719 pin_range = kzalloc(sizeof(*pin_range), GFP_KERNEL);
721 chip_err(chip, "failed to allocate pin ranges\n");
725 /* Use local offset as range ID */
726 pin_range->range.id = gpio_offset;
727 pin_range->range.gc = chip;
728 pin_range->range.name = chip->label;
729 pin_range->range.base = chip->base + gpio_offset;
730 pin_range->range.pin_base = pin_offset;
731 pin_range->range.npins = npins;
732 pin_range->pctldev = pinctrl_find_and_add_gpio_range(pinctl_name,
734 if (IS_ERR(pin_range->pctldev)) {
735 ret = PTR_ERR(pin_range->pctldev);
736 chip_err(chip, "could not create pin range\n");
740 chip_dbg(chip, "created GPIO range %d->%d ==> %s PIN %d->%d\n",
741 gpio_offset, gpio_offset + npins - 1,
743 pin_offset, pin_offset + npins - 1);
745 list_add_tail(&pin_range->node, &chip->pin_ranges);
749 EXPORT_SYMBOL_GPL(gpiochip_add_pin_range);
752 * gpiochip_remove_pin_ranges() - remove all the GPIO <-> pin mappings
753 * @chip: the chip to remove all the mappings for
755 void gpiochip_remove_pin_ranges(struct gpio_chip *chip)
757 struct gpio_pin_range *pin_range, *tmp;
759 list_for_each_entry_safe(pin_range, tmp, &chip->pin_ranges, node) {
760 list_del(&pin_range->node);
761 pinctrl_remove_gpio_range(pin_range->pctldev,
766 EXPORT_SYMBOL_GPL(gpiochip_remove_pin_ranges);
768 #endif /* CONFIG_PINCTRL */
770 /* These "optional" allocation calls help prevent drivers from stomping
771 * on each other, and help provide better diagnostics in debugfs.
772 * They're called even less than the "set direction" calls.
774 static int __gpiod_request(struct gpio_desc *desc, const char *label)
776 struct gpio_chip *chip = desc->chip;
780 spin_lock_irqsave(&gpio_lock, flags);
782 /* NOTE: gpio_request() can be called in early boot,
783 * before IRQs are enabled, for non-sleeping (SOC) GPIOs.
786 if (test_and_set_bit(FLAG_REQUESTED, &desc->flags) == 0) {
787 desc_set_label(desc, label ? : "?");
795 /* chip->request may sleep */
796 spin_unlock_irqrestore(&gpio_lock, flags);
797 status = chip->request(chip, gpio_chip_hwgpio(desc));
798 spin_lock_irqsave(&gpio_lock, flags);
801 desc_set_label(desc, NULL);
802 clear_bit(FLAG_REQUESTED, &desc->flags);
806 if (chip->get_direction) {
807 /* chip->get_direction may sleep */
808 spin_unlock_irqrestore(&gpio_lock, flags);
809 gpiod_get_direction(desc);
810 spin_lock_irqsave(&gpio_lock, flags);
813 spin_unlock_irqrestore(&gpio_lock, flags);
817 int gpiod_request(struct gpio_desc *desc, const char *label)
819 int status = -EPROBE_DEFER;
820 struct gpio_chip *chip;
823 pr_warn("%s: invalid GPIO\n", __func__);
831 if (try_module_get(chip->owner)) {
832 status = __gpiod_request(desc, label);
834 module_put(chip->owner);
839 gpiod_dbg(desc, "%s: status %d\n", __func__, status);
844 static bool __gpiod_free(struct gpio_desc *desc)
848 struct gpio_chip *chip;
852 gpiod_unexport(desc);
854 spin_lock_irqsave(&gpio_lock, flags);
857 if (chip && test_bit(FLAG_REQUESTED, &desc->flags)) {
859 spin_unlock_irqrestore(&gpio_lock, flags);
860 might_sleep_if(chip->can_sleep);
861 chip->free(chip, gpio_chip_hwgpio(desc));
862 spin_lock_irqsave(&gpio_lock, flags);
864 desc_set_label(desc, NULL);
865 clear_bit(FLAG_ACTIVE_LOW, &desc->flags);
866 clear_bit(FLAG_REQUESTED, &desc->flags);
867 clear_bit(FLAG_OPEN_DRAIN, &desc->flags);
868 clear_bit(FLAG_OPEN_SOURCE, &desc->flags);
872 spin_unlock_irqrestore(&gpio_lock, flags);
876 void gpiod_free(struct gpio_desc *desc)
878 if (desc && __gpiod_free(desc))
879 module_put(desc->chip->owner);
881 WARN_ON(extra_checks);
885 * gpiochip_is_requested - return string iff signal was requested
886 * @chip: controller managing the signal
887 * @offset: of signal within controller's 0..(ngpio - 1) range
889 * Returns NULL if the GPIO is not currently requested, else a string.
890 * The string returned is the label passed to gpio_request(); if none has been
891 * passed it is a meaningless, non-NULL constant.
893 * This function is for use by GPIO controller drivers. The label can
894 * help with diagnostics, and knowing that the signal is used as a GPIO
895 * can help avoid accidentally multiplexing it to another controller.
897 const char *gpiochip_is_requested(struct gpio_chip *chip, unsigned offset)
899 struct gpio_desc *desc;
901 if (!GPIO_OFFSET_VALID(chip, offset))
904 desc = &chip->desc[offset];
906 if (test_bit(FLAG_REQUESTED, &desc->flags) == 0)
910 EXPORT_SYMBOL_GPL(gpiochip_is_requested);
913 * gpiochip_request_own_desc - Allow GPIO chip to request its own descriptor
914 * @desc: GPIO descriptor to request
915 * @label: label for the GPIO
917 * Function allows GPIO chip drivers to request and use their own GPIO
918 * descriptors via gpiolib API. Difference to gpiod_request() is that this
919 * function will not increase reference count of the GPIO chip module. This
920 * allows the GPIO chip module to be unloaded as needed (we assume that the
921 * GPIO chip driver handles freeing the GPIOs it has requested).
923 struct gpio_desc *gpiochip_request_own_desc(struct gpio_chip *chip, u16 hwnum,
926 struct gpio_desc *desc = gpiochip_get_desc(chip, hwnum);
930 chip_err(chip, "failed to get GPIO descriptor\n");
934 err = __gpiod_request(desc, label);
940 EXPORT_SYMBOL_GPL(gpiochip_request_own_desc);
943 * gpiochip_free_own_desc - Free GPIO requested by the chip driver
944 * @desc: GPIO descriptor to free
946 * Function frees the given GPIO requested previously with
947 * gpiochip_request_own_desc().
949 void gpiochip_free_own_desc(struct gpio_desc *desc)
954 EXPORT_SYMBOL_GPL(gpiochip_free_own_desc);
956 /* Drivers MUST set GPIO direction before making get/set calls. In
957 * some cases this is done in early boot, before IRQs are enabled.
959 * As a rule these aren't called more than once (except for drivers
960 * using the open-drain emulation idiom) so these are natural places
961 * to accumulate extra debugging checks. Note that we can't (yet)
962 * rely on gpio_request() having been called beforehand.
966 * gpiod_direction_input - set the GPIO direction to input
967 * @desc: GPIO to set to input
969 * Set the direction of the passed GPIO to input, such as gpiod_get_value() can
970 * be called safely on it.
972 * Return 0 in case of success, else an error code.
974 int gpiod_direction_input(struct gpio_desc *desc)
976 struct gpio_chip *chip;
977 int status = -EINVAL;
979 if (!desc || !desc->chip) {
980 pr_warn("%s: invalid GPIO\n", __func__);
985 if (!chip->get || !chip->direction_input) {
987 "%s: missing get() or direction_input() operations\n",
992 status = chip->direction_input(chip, gpio_chip_hwgpio(desc));
994 clear_bit(FLAG_IS_OUT, &desc->flags);
996 trace_gpio_direction(desc_to_gpio(desc), 1, status);
1000 EXPORT_SYMBOL_GPL(gpiod_direction_input);
1002 static int _gpiod_direction_output_raw(struct gpio_desc *desc, int value)
1004 struct gpio_chip *chip;
1005 int status = -EINVAL;
1007 /* GPIOs used for IRQs shall not be set as output */
1008 if (test_bit(FLAG_USED_AS_IRQ, &desc->flags)) {
1010 "%s: tried to set a GPIO tied to an IRQ as output\n",
1015 /* Open drain pin should not be driven to 1 */
1016 if (value && test_bit(FLAG_OPEN_DRAIN, &desc->flags))
1017 return gpiod_direction_input(desc);
1019 /* Open source pin should not be driven to 0 */
1020 if (!value && test_bit(FLAG_OPEN_SOURCE, &desc->flags))
1021 return gpiod_direction_input(desc);
1024 if (!chip->set || !chip->direction_output) {
1026 "%s: missing set() or direction_output() operations\n",
1031 status = chip->direction_output(chip, gpio_chip_hwgpio(desc), value);
1033 set_bit(FLAG_IS_OUT, &desc->flags);
1034 trace_gpio_value(desc_to_gpio(desc), 0, value);
1035 trace_gpio_direction(desc_to_gpio(desc), 0, status);
1040 * gpiod_direction_output_raw - set the GPIO direction to output
1041 * @desc: GPIO to set to output
1042 * @value: initial output value of the GPIO
1044 * Set the direction of the passed GPIO to output, such as gpiod_set_value() can
1045 * be called safely on it. The initial value of the output must be specified
1046 * as raw value on the physical line without regard for the ACTIVE_LOW status.
1048 * Return 0 in case of success, else an error code.
1050 int gpiod_direction_output_raw(struct gpio_desc *desc, int value)
1052 if (!desc || !desc->chip) {
1053 pr_warn("%s: invalid GPIO\n", __func__);
1056 return _gpiod_direction_output_raw(desc, value);
1058 EXPORT_SYMBOL_GPL(gpiod_direction_output_raw);
1061 * gpiod_direction_output - set the GPIO direction to output
1062 * @desc: GPIO to set to output
1063 * @value: initial output value of the GPIO
1065 * Set the direction of the passed GPIO to output, such as gpiod_set_value() can
1066 * be called safely on it. The initial value of the output must be specified
1067 * as the logical value of the GPIO, i.e. taking its ACTIVE_LOW status into
1070 * Return 0 in case of success, else an error code.
1072 int gpiod_direction_output(struct gpio_desc *desc, int value)
1074 if (!desc || !desc->chip) {
1075 pr_warn("%s: invalid GPIO\n", __func__);
1078 if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
1080 return _gpiod_direction_output_raw(desc, value);
1082 EXPORT_SYMBOL_GPL(gpiod_direction_output);
1085 * gpiod_set_debounce - sets @debounce time for a @gpio
1086 * @gpio: the gpio to set debounce time
1087 * @debounce: debounce time is microseconds
1089 * returns -ENOTSUPP if the controller does not support setting
1092 int gpiod_set_debounce(struct gpio_desc *desc, unsigned debounce)
1094 struct gpio_chip *chip;
1096 if (!desc || !desc->chip) {
1097 pr_warn("%s: invalid GPIO\n", __func__);
1102 if (!chip->set || !chip->set_debounce) {
1104 "%s: missing set() or set_debounce() operations\n",
1109 return chip->set_debounce(chip, gpio_chip_hwgpio(desc), debounce);
1111 EXPORT_SYMBOL_GPL(gpiod_set_debounce);
1114 * gpiod_is_active_low - test whether a GPIO is active-low or not
1115 * @desc: the gpio descriptor to test
1117 * Returns 1 if the GPIO is active-low, 0 otherwise.
1119 int gpiod_is_active_low(const struct gpio_desc *desc)
1121 return test_bit(FLAG_ACTIVE_LOW, &desc->flags);
1123 EXPORT_SYMBOL_GPL(gpiod_is_active_low);
1125 /* I/O calls are only valid after configuration completed; the relevant
1126 * "is this a valid GPIO" error checks should already have been done.
1128 * "Get" operations are often inlinable as reading a pin value register,
1129 * and masking the relevant bit in that register.
1131 * When "set" operations are inlinable, they involve writing that mask to
1132 * one register to set a low value, or a different register to set it high.
1133 * Otherwise locking is needed, so there may be little value to inlining.
1135 *------------------------------------------------------------------------
1137 * IMPORTANT!!! The hot paths -- get/set value -- assume that callers
1138 * have requested the GPIO. That can include implicit requesting by
1139 * a direction setting call. Marking a gpio as requested locks its chip
1140 * in memory, guaranteeing that these table lookups need no more locking
1141 * and that gpiochip_remove() will fail.
1143 * REVISIT when debugging, consider adding some instrumentation to ensure
1144 * that the GPIO was actually requested.
1147 static bool _gpiod_get_raw_value(const struct gpio_desc *desc)
1149 struct gpio_chip *chip;
1154 offset = gpio_chip_hwgpio(desc);
1155 value = chip->get ? chip->get(chip, offset) : false;
1156 trace_gpio_value(desc_to_gpio(desc), 1, value);
1161 * gpiod_get_raw_value() - return a gpio's raw value
1162 * @desc: gpio whose value will be returned
1164 * Return the GPIO's raw value, i.e. the value of the physical line disregarding
1165 * its ACTIVE_LOW status.
1167 * This function should be called from contexts where we cannot sleep, and will
1168 * complain if the GPIO chip functions potentially sleep.
1170 int gpiod_get_raw_value(const struct gpio_desc *desc)
1174 /* Should be using gpio_get_value_cansleep() */
1175 WARN_ON(desc->chip->can_sleep);
1176 return _gpiod_get_raw_value(desc);
1178 EXPORT_SYMBOL_GPL(gpiod_get_raw_value);
1181 * gpiod_get_value() - return a gpio's value
1182 * @desc: gpio whose value will be returned
1184 * Return the GPIO's logical value, i.e. taking the ACTIVE_LOW status into
1187 * This function should be called from contexts where we cannot sleep, and will
1188 * complain if the GPIO chip functions potentially sleep.
1190 int gpiod_get_value(const struct gpio_desc *desc)
1195 /* Should be using gpio_get_value_cansleep() */
1196 WARN_ON(desc->chip->can_sleep);
1198 value = _gpiod_get_raw_value(desc);
1199 if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
1204 EXPORT_SYMBOL_GPL(gpiod_get_value);
1207 * _gpio_set_open_drain_value() - Set the open drain gpio's value.
1208 * @desc: gpio descriptor whose state need to be set.
1209 * @value: Non-zero for setting it HIGH otherise it will set to LOW.
1211 static void _gpio_set_open_drain_value(struct gpio_desc *desc, bool value)
1214 struct gpio_chip *chip = desc->chip;
1215 int offset = gpio_chip_hwgpio(desc);
1218 err = chip->direction_input(chip, offset);
1220 clear_bit(FLAG_IS_OUT, &desc->flags);
1222 err = chip->direction_output(chip, offset, 0);
1224 set_bit(FLAG_IS_OUT, &desc->flags);
1226 trace_gpio_direction(desc_to_gpio(desc), value, err);
1229 "%s: Error in set_value for open drain err %d\n",
1234 * _gpio_set_open_source_value() - Set the open source gpio's value.
1235 * @desc: gpio descriptor whose state need to be set.
1236 * @value: Non-zero for setting it HIGH otherise it will set to LOW.
1238 static void _gpio_set_open_source_value(struct gpio_desc *desc, bool value)
1241 struct gpio_chip *chip = desc->chip;
1242 int offset = gpio_chip_hwgpio(desc);
1245 err = chip->direction_output(chip, offset, 1);
1247 set_bit(FLAG_IS_OUT, &desc->flags);
1249 err = chip->direction_input(chip, offset);
1251 clear_bit(FLAG_IS_OUT, &desc->flags);
1253 trace_gpio_direction(desc_to_gpio(desc), !value, err);
1256 "%s: Error in set_value for open source err %d\n",
1260 static void _gpiod_set_raw_value(struct gpio_desc *desc, bool value)
1262 struct gpio_chip *chip;
1265 trace_gpio_value(desc_to_gpio(desc), 0, value);
1266 if (test_bit(FLAG_OPEN_DRAIN, &desc->flags))
1267 _gpio_set_open_drain_value(desc, value);
1268 else if (test_bit(FLAG_OPEN_SOURCE, &desc->flags))
1269 _gpio_set_open_source_value(desc, value);
1271 chip->set(chip, gpio_chip_hwgpio(desc), value);
1275 * set multiple outputs on the same chip;
1276 * use the chip's set_multiple function if available;
1277 * otherwise set the outputs sequentially;
1278 * @mask: bit mask array; one bit per output; BITS_PER_LONG bits per word
1279 * defines which outputs are to be changed
1280 * @bits: bit value array; one bit per output; BITS_PER_LONG bits per word
1281 * defines the values the outputs specified by mask are to be set to
1283 static void gpio_chip_set_multiple(struct gpio_chip *chip,
1284 unsigned long *mask, unsigned long *bits)
1286 if (chip->set_multiple) {
1287 chip->set_multiple(chip, mask, bits);
1290 for (i = 0; i < chip->ngpio; i++) {
1291 if (mask[BIT_WORD(i)] == 0) {
1292 /* no more set bits in this mask word;
1293 * skip ahead to the next word */
1294 i = (BIT_WORD(i) + 1) * BITS_PER_LONG - 1;
1297 /* set outputs if the corresponding mask bit is set */
1298 if (__test_and_clear_bit(i, mask)) {
1299 chip->set(chip, i, test_bit(i, bits));
1305 static void gpiod_set_array_priv(bool raw, bool can_sleep,
1306 unsigned int array_size,
1307 struct gpio_desc **desc_array,
1312 while (i < array_size) {
1313 struct gpio_chip *chip = desc_array[i]->chip;
1314 unsigned long mask[BITS_TO_LONGS(chip->ngpio)];
1315 unsigned long bits[BITS_TO_LONGS(chip->ngpio)];
1319 WARN_ON(chip->can_sleep);
1321 memset(mask, 0, sizeof(mask));
1323 struct gpio_desc *desc = desc_array[i];
1324 int hwgpio = gpio_chip_hwgpio(desc);
1325 int value = value_array[i];
1327 if (!raw && test_bit(FLAG_ACTIVE_LOW, &desc->flags))
1329 trace_gpio_value(desc_to_gpio(desc), 0, value);
1331 * collect all normal outputs belonging to the same chip
1332 * open drain and open source outputs are set individually
1334 if (test_bit(FLAG_OPEN_DRAIN, &desc->flags)) {
1335 _gpio_set_open_drain_value(desc,value);
1336 } else if (test_bit(FLAG_OPEN_SOURCE, &desc->flags)) {
1337 _gpio_set_open_source_value(desc, value);
1339 __set_bit(hwgpio, mask);
1341 __set_bit(hwgpio, bits);
1343 __clear_bit(hwgpio, bits);
1348 } while ((i < array_size) && (desc_array[i]->chip == chip));
1349 /* push collected bits to outputs */
1351 gpio_chip_set_multiple(chip, mask, bits);
1357 * gpiod_set_raw_value() - assign a gpio's raw value
1358 * @desc: gpio whose value will be assigned
1359 * @value: value to assign
1361 * Set the raw value of the GPIO, i.e. the value of its physical line without
1362 * regard for its ACTIVE_LOW status.
1364 * This function should be called from contexts where we cannot sleep, and will
1365 * complain if the GPIO chip functions potentially sleep.
1367 void gpiod_set_raw_value(struct gpio_desc *desc, int value)
1371 /* Should be using gpio_set_value_cansleep() */
1372 WARN_ON(desc->chip->can_sleep);
1373 _gpiod_set_raw_value(desc, value);
1375 EXPORT_SYMBOL_GPL(gpiod_set_raw_value);
1378 * gpiod_set_value() - assign a gpio's value
1379 * @desc: gpio whose value will be assigned
1380 * @value: value to assign
1382 * Set the logical value of the GPIO, i.e. taking its ACTIVE_LOW status into
1385 * This function should be called from contexts where we cannot sleep, and will
1386 * complain if the GPIO chip functions potentially sleep.
1388 void gpiod_set_value(struct gpio_desc *desc, int value)
1392 /* Should be using gpio_set_value_cansleep() */
1393 WARN_ON(desc->chip->can_sleep);
1394 if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
1396 _gpiod_set_raw_value(desc, value);
1398 EXPORT_SYMBOL_GPL(gpiod_set_value);
1401 * gpiod_set_raw_array() - assign values to an array of GPIOs
1402 * @array_size: number of elements in the descriptor / value arrays
1403 * @desc_array: array of GPIO descriptors whose values will be assigned
1404 * @value_array: array of values to assign
1406 * Set the raw values of the GPIOs, i.e. the values of the physical lines
1407 * without regard for their ACTIVE_LOW status.
1409 * This function should be called from contexts where we cannot sleep, and will
1410 * complain if the GPIO chip functions potentially sleep.
1412 void gpiod_set_raw_array(unsigned int array_size,
1413 struct gpio_desc **desc_array, int *value_array)
1417 gpiod_set_array_priv(true, false, array_size, desc_array, value_array);
1419 EXPORT_SYMBOL_GPL(gpiod_set_raw_array);
1422 * gpiod_set_array() - assign values to an array of GPIOs
1423 * @array_size: number of elements in the descriptor / value arrays
1424 * @desc_array: array of GPIO descriptors whose values will be assigned
1425 * @value_array: array of values to assign
1427 * Set the logical values of the GPIOs, i.e. taking their ACTIVE_LOW status
1430 * This function should be called from contexts where we cannot sleep, and will
1431 * complain if the GPIO chip functions potentially sleep.
1433 void gpiod_set_array(unsigned int array_size,
1434 struct gpio_desc **desc_array, int *value_array)
1438 gpiod_set_array_priv(false, false, array_size, desc_array, value_array);
1440 EXPORT_SYMBOL_GPL(gpiod_set_array);
1443 * gpiod_cansleep() - report whether gpio value access may sleep
1444 * @desc: gpio to check
1447 int gpiod_cansleep(const struct gpio_desc *desc)
1451 return desc->chip->can_sleep;
1453 EXPORT_SYMBOL_GPL(gpiod_cansleep);
1456 * gpiod_to_irq() - return the IRQ corresponding to a GPIO
1457 * @desc: gpio whose IRQ will be returned (already requested)
1459 * Return the IRQ corresponding to the passed GPIO, or an error code in case of
1462 int gpiod_to_irq(const struct gpio_desc *desc)
1464 struct gpio_chip *chip;
1470 offset = gpio_chip_hwgpio(desc);
1471 return chip->to_irq ? chip->to_irq(chip, offset) : -ENXIO;
1473 EXPORT_SYMBOL_GPL(gpiod_to_irq);
1476 * gpiochip_lock_as_irq() - lock a GPIO to be used as IRQ
1477 * @chip: the chip the GPIO to lock belongs to
1478 * @offset: the offset of the GPIO to lock as IRQ
1480 * This is used directly by GPIO drivers that want to lock down
1481 * a certain GPIO line to be used for IRQs.
1483 int gpiochip_lock_as_irq(struct gpio_chip *chip, unsigned int offset)
1485 if (offset >= chip->ngpio)
1488 if (test_bit(FLAG_IS_OUT, &chip->desc[offset].flags)) {
1490 "%s: tried to flag a GPIO set as output for IRQ\n",
1495 set_bit(FLAG_USED_AS_IRQ, &chip->desc[offset].flags);
1498 EXPORT_SYMBOL_GPL(gpiochip_lock_as_irq);
1501 * gpiochip_unlock_as_irq() - unlock a GPIO used as IRQ
1502 * @chip: the chip the GPIO to lock belongs to
1503 * @offset: the offset of the GPIO to lock as IRQ
1505 * This is used directly by GPIO drivers that want to indicate
1506 * that a certain GPIO is no longer used exclusively for IRQ.
1508 void gpiochip_unlock_as_irq(struct gpio_chip *chip, unsigned int offset)
1510 if (offset >= chip->ngpio)
1513 clear_bit(FLAG_USED_AS_IRQ, &chip->desc[offset].flags);
1515 EXPORT_SYMBOL_GPL(gpiochip_unlock_as_irq);
1518 * gpiod_get_raw_value_cansleep() - return a gpio's raw value
1519 * @desc: gpio whose value will be returned
1521 * Return the GPIO's raw value, i.e. the value of the physical line disregarding
1522 * its ACTIVE_LOW status.
1524 * This function is to be called from contexts that can sleep.
1526 int gpiod_get_raw_value_cansleep(const struct gpio_desc *desc)
1528 might_sleep_if(extra_checks);
1531 return _gpiod_get_raw_value(desc);
1533 EXPORT_SYMBOL_GPL(gpiod_get_raw_value_cansleep);
1536 * gpiod_get_value_cansleep() - return a gpio's value
1537 * @desc: gpio whose value will be returned
1539 * Return the GPIO's logical value, i.e. taking the ACTIVE_LOW status into
1542 * This function is to be called from contexts that can sleep.
1544 int gpiod_get_value_cansleep(const struct gpio_desc *desc)
1548 might_sleep_if(extra_checks);
1552 value = _gpiod_get_raw_value(desc);
1553 if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
1558 EXPORT_SYMBOL_GPL(gpiod_get_value_cansleep);
1561 * gpiod_set_raw_value_cansleep() - assign a gpio's raw value
1562 * @desc: gpio whose value will be assigned
1563 * @value: value to assign
1565 * Set the raw value of the GPIO, i.e. the value of its physical line without
1566 * regard for its ACTIVE_LOW status.
1568 * This function is to be called from contexts that can sleep.
1570 void gpiod_set_raw_value_cansleep(struct gpio_desc *desc, int value)
1572 might_sleep_if(extra_checks);
1575 _gpiod_set_raw_value(desc, value);
1577 EXPORT_SYMBOL_GPL(gpiod_set_raw_value_cansleep);
1580 * gpiod_set_value_cansleep() - assign a gpio's value
1581 * @desc: gpio whose value will be assigned
1582 * @value: value to assign
1584 * Set the logical value of the GPIO, i.e. taking its ACTIVE_LOW status into
1587 * This function is to be called from contexts that can sleep.
1589 void gpiod_set_value_cansleep(struct gpio_desc *desc, int value)
1591 might_sleep_if(extra_checks);
1595 if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
1597 _gpiod_set_raw_value(desc, value);
1599 EXPORT_SYMBOL_GPL(gpiod_set_value_cansleep);
1602 * gpiod_set_raw_array_cansleep() - assign values to an array of GPIOs
1603 * @array_size: number of elements in the descriptor / value arrays
1604 * @desc_array: array of GPIO descriptors whose values will be assigned
1605 * @value_array: array of values to assign
1607 * Set the raw values of the GPIOs, i.e. the values of the physical lines
1608 * without regard for their ACTIVE_LOW status.
1610 * This function is to be called from contexts that can sleep.
1612 void gpiod_set_raw_array_cansleep(unsigned int array_size,
1613 struct gpio_desc **desc_array,
1616 might_sleep_if(extra_checks);
1619 gpiod_set_array_priv(true, true, array_size, desc_array, value_array);
1621 EXPORT_SYMBOL_GPL(gpiod_set_raw_array_cansleep);
1624 * gpiod_set_array_cansleep() - assign values to an array of GPIOs
1625 * @array_size: number of elements in the descriptor / value arrays
1626 * @desc_array: array of GPIO descriptors whose values will be assigned
1627 * @value_array: array of values to assign
1629 * Set the logical values of the GPIOs, i.e. taking their ACTIVE_LOW status
1632 * This function is to be called from contexts that can sleep.
1634 void gpiod_set_array_cansleep(unsigned int array_size,
1635 struct gpio_desc **desc_array,
1638 might_sleep_if(extra_checks);
1641 gpiod_set_array_priv(false, true, array_size, desc_array, value_array);
1643 EXPORT_SYMBOL_GPL(gpiod_set_array_cansleep);
1646 * gpiod_add_lookup_table() - register GPIO device consumers
1647 * @table: table of consumers to register
1649 void gpiod_add_lookup_table(struct gpiod_lookup_table *table)
1651 mutex_lock(&gpio_lookup_lock);
1653 list_add_tail(&table->list, &gpio_lookup_list);
1655 mutex_unlock(&gpio_lookup_lock);
1658 static struct gpio_desc *of_find_gpio(struct device *dev, const char *con_id,
1660 enum gpio_lookup_flags *flags)
1662 static const char * const suffixes[] = { "gpios", "gpio" };
1663 char prop_name[32]; /* 32 is max size of property name */
1664 enum of_gpio_flags of_flags;
1665 struct gpio_desc *desc;
1668 for (i = 0; i < ARRAY_SIZE(suffixes); i++) {
1670 snprintf(prop_name, sizeof(prop_name), "%s-%s", con_id,
1673 snprintf(prop_name, sizeof(prop_name), "%s",
1676 desc = of_get_named_gpiod_flags(dev->of_node, prop_name, idx,
1678 if (!IS_ERR(desc) || (PTR_ERR(desc) == -EPROBE_DEFER))
1685 if (of_flags & OF_GPIO_ACTIVE_LOW)
1686 *flags |= GPIO_ACTIVE_LOW;
1691 static struct gpio_desc *acpi_find_gpio(struct device *dev, const char *con_id,
1693 enum gpio_lookup_flags *flags)
1695 static const char * const suffixes[] = { "gpios", "gpio" };
1696 struct acpi_device *adev = ACPI_COMPANION(dev);
1697 struct acpi_gpio_info info;
1698 struct gpio_desc *desc;
1702 /* Try first from _DSD */
1703 for (i = 0; i < ARRAY_SIZE(suffixes); i++) {
1704 if (con_id && strcmp(con_id, "gpios")) {
1705 snprintf(propname, sizeof(propname), "%s-%s",
1706 con_id, suffixes[i]);
1708 snprintf(propname, sizeof(propname), "%s",
1712 desc = acpi_get_gpiod_by_index(adev, propname, idx, &info);
1713 if (!IS_ERR(desc) || (PTR_ERR(desc) == -EPROBE_DEFER))
1717 /* Then from plain _CRS GPIOs */
1719 desc = acpi_get_gpiod_by_index(adev, NULL, idx, &info);
1724 if (info.active_low)
1725 *flags |= GPIO_ACTIVE_LOW;
1730 static struct gpiod_lookup_table *gpiod_find_lookup_table(struct device *dev)
1732 const char *dev_id = dev ? dev_name(dev) : NULL;
1733 struct gpiod_lookup_table *table;
1735 mutex_lock(&gpio_lookup_lock);
1737 list_for_each_entry(table, &gpio_lookup_list, list) {
1738 if (table->dev_id && dev_id) {
1740 * Valid strings on both ends, must be identical to have
1743 if (!strcmp(table->dev_id, dev_id))
1747 * One of the pointers is NULL, so both must be to have
1750 if (dev_id == table->dev_id)
1757 mutex_unlock(&gpio_lookup_lock);
1761 static struct gpio_desc *gpiod_find(struct device *dev, const char *con_id,
1763 enum gpio_lookup_flags *flags)
1765 struct gpio_desc *desc = ERR_PTR(-ENOENT);
1766 struct gpiod_lookup_table *table;
1767 struct gpiod_lookup *p;
1769 table = gpiod_find_lookup_table(dev);
1773 for (p = &table->table[0]; p->chip_label; p++) {
1774 struct gpio_chip *chip;
1776 /* idx must always match exactly */
1780 /* If the lookup entry has a con_id, require exact match */
1781 if (p->con_id && (!con_id || strcmp(p->con_id, con_id)))
1784 chip = find_chip_by_name(p->chip_label);
1787 dev_err(dev, "cannot find GPIO chip %s\n",
1789 return ERR_PTR(-ENODEV);
1792 if (chip->ngpio <= p->chip_hwnum) {
1794 "requested GPIO %d is out of range [0..%d] for chip %s\n",
1795 idx, chip->ngpio, chip->label);
1796 return ERR_PTR(-EINVAL);
1799 desc = gpiochip_get_desc(chip, p->chip_hwnum);
1809 * gpiod_get - obtain a GPIO for a given GPIO function
1810 * @dev: GPIO consumer, can be NULL for system-global GPIOs
1811 * @con_id: function within the GPIO consumer
1812 * @flags: optional GPIO initialization flags
1814 * Return the GPIO descriptor corresponding to the function con_id of device
1815 * dev, -ENOENT if no GPIO has been assigned to the requested function, or
1816 * another IS_ERR() code if an error occured while trying to acquire the GPIO.
1818 struct gpio_desc *__must_check __gpiod_get(struct device *dev, const char *con_id,
1819 enum gpiod_flags flags)
1821 return gpiod_get_index(dev, con_id, 0, flags);
1823 EXPORT_SYMBOL_GPL(__gpiod_get);
1826 * gpiod_get_optional - obtain an optional GPIO for a given GPIO function
1827 * @dev: GPIO consumer, can be NULL for system-global GPIOs
1828 * @con_id: function within the GPIO consumer
1829 * @flags: optional GPIO initialization flags
1831 * This is equivalent to gpiod_get(), except that when no GPIO was assigned to
1832 * the requested function it will return NULL. This is convenient for drivers
1833 * that need to handle optional GPIOs.
1835 struct gpio_desc *__must_check __gpiod_get_optional(struct device *dev,
1837 enum gpiod_flags flags)
1839 return gpiod_get_index_optional(dev, con_id, 0, flags);
1841 EXPORT_SYMBOL_GPL(__gpiod_get_optional);
1844 * gpiod_get_index - obtain a GPIO from a multi-index GPIO function
1845 * @dev: GPIO consumer, can be NULL for system-global GPIOs
1846 * @con_id: function within the GPIO consumer
1847 * @idx: index of the GPIO to obtain in the consumer
1848 * @flags: optional GPIO initialization flags
1850 * This variant of gpiod_get() allows to access GPIOs other than the first
1851 * defined one for functions that define several GPIOs.
1853 * Return a valid GPIO descriptor, -ENOENT if no GPIO has been assigned to the
1854 * requested function and/or index, or another IS_ERR() code if an error
1855 * occured while trying to acquire the GPIO.
1857 struct gpio_desc *__must_check __gpiod_get_index(struct device *dev,
1860 enum gpiod_flags flags)
1862 struct gpio_desc *desc = NULL;
1864 enum gpio_lookup_flags lookupflags = 0;
1866 dev_dbg(dev, "GPIO lookup for consumer %s\n", con_id);
1868 /* Using device tree? */
1869 if (IS_ENABLED(CONFIG_OF) && dev && dev->of_node) {
1870 dev_dbg(dev, "using device tree for GPIO lookup\n");
1871 desc = of_find_gpio(dev, con_id, idx, &lookupflags);
1872 } else if (IS_ENABLED(CONFIG_ACPI) && dev && ACPI_HANDLE(dev)) {
1873 dev_dbg(dev, "using ACPI for GPIO lookup\n");
1874 desc = acpi_find_gpio(dev, con_id, idx, &lookupflags);
1878 * Either we are not using DT or ACPI, or their lookup did not return
1879 * a result. In that case, use platform lookup as a fallback.
1881 if (!desc || desc == ERR_PTR(-ENOENT)) {
1882 dev_dbg(dev, "using lookup tables for GPIO lookup\n");
1883 desc = gpiod_find(dev, con_id, idx, &lookupflags);
1887 dev_dbg(dev, "lookup for GPIO %s failed\n", con_id);
1891 status = gpiod_request(desc, con_id);
1894 return ERR_PTR(status);
1896 if (lookupflags & GPIO_ACTIVE_LOW)
1897 set_bit(FLAG_ACTIVE_LOW, &desc->flags);
1898 if (lookupflags & GPIO_OPEN_DRAIN)
1899 set_bit(FLAG_OPEN_DRAIN, &desc->flags);
1900 if (lookupflags & GPIO_OPEN_SOURCE)
1901 set_bit(FLAG_OPEN_SOURCE, &desc->flags);
1903 /* No particular flag request, return here... */
1904 if (!(flags & GPIOD_FLAGS_BIT_DIR_SET))
1908 if (flags & GPIOD_FLAGS_BIT_DIR_OUT)
1909 status = gpiod_direction_output(desc,
1910 flags & GPIOD_FLAGS_BIT_DIR_VAL);
1912 status = gpiod_direction_input(desc);
1915 dev_dbg(dev, "setup of GPIO %s failed\n", con_id);
1917 return ERR_PTR(status);
1922 EXPORT_SYMBOL_GPL(__gpiod_get_index);
1925 * fwnode_get_named_gpiod - obtain a GPIO from firmware node
1926 * @fwnode: handle of the firmware node
1927 * @propname: name of the firmware property representing the GPIO
1929 * This function can be used for drivers that get their configuration
1932 * Function properly finds the corresponding GPIO using whatever is the
1933 * underlying firmware interface and then makes sure that the GPIO
1934 * descriptor is requested before it is returned to the caller.
1936 * In case of error an ERR_PTR() is returned.
1938 struct gpio_desc *fwnode_get_named_gpiod(struct fwnode_handle *fwnode,
1939 const char *propname)
1941 struct gpio_desc *desc = ERR_PTR(-ENODEV);
1942 bool active_low = false;
1946 return ERR_PTR(-EINVAL);
1948 if (is_of_node(fwnode)) {
1949 enum of_gpio_flags flags;
1951 desc = of_get_named_gpiod_flags(of_node(fwnode), propname, 0,
1954 active_low = flags & OF_GPIO_ACTIVE_LOW;
1955 } else if (is_acpi_node(fwnode)) {
1956 struct acpi_gpio_info info;
1958 desc = acpi_get_gpiod_by_index(acpi_node(fwnode), propname, 0,
1961 active_low = info.active_low;
1967 ret = gpiod_request(desc, NULL);
1969 return ERR_PTR(ret);
1971 /* Only value flag can be set from both DT and ACPI is active_low */
1973 set_bit(FLAG_ACTIVE_LOW, &desc->flags);
1977 EXPORT_SYMBOL_GPL(fwnode_get_named_gpiod);
1980 * gpiod_get_index_optional - obtain an optional GPIO from a multi-index GPIO
1982 * @dev: GPIO consumer, can be NULL for system-global GPIOs
1983 * @con_id: function within the GPIO consumer
1984 * @index: index of the GPIO to obtain in the consumer
1985 * @flags: optional GPIO initialization flags
1987 * This is equivalent to gpiod_get_index(), except that when no GPIO with the
1988 * specified index was assigned to the requested function it will return NULL.
1989 * This is convenient for drivers that need to handle optional GPIOs.
1991 struct gpio_desc *__must_check __gpiod_get_index_optional(struct device *dev,
1994 enum gpiod_flags flags)
1996 struct gpio_desc *desc;
1998 desc = gpiod_get_index(dev, con_id, index, flags);
2000 if (PTR_ERR(desc) == -ENOENT)
2006 EXPORT_SYMBOL_GPL(__gpiod_get_index_optional);
2009 * gpiod_put - dispose of a GPIO descriptor
2010 * @desc: GPIO descriptor to dispose of
2012 * No descriptor can be used after gpiod_put() has been called on it.
2014 void gpiod_put(struct gpio_desc *desc)
2018 EXPORT_SYMBOL_GPL(gpiod_put);
2020 #ifdef CONFIG_DEBUG_FS
2022 static void gpiolib_dbg_show(struct seq_file *s, struct gpio_chip *chip)
2025 unsigned gpio = chip->base;
2026 struct gpio_desc *gdesc = &chip->desc[0];
2030 for (i = 0; i < chip->ngpio; i++, gpio++, gdesc++) {
2031 if (!test_bit(FLAG_REQUESTED, &gdesc->flags))
2034 gpiod_get_direction(gdesc);
2035 is_out = test_bit(FLAG_IS_OUT, &gdesc->flags);
2036 is_irq = test_bit(FLAG_USED_AS_IRQ, &gdesc->flags);
2037 seq_printf(s, " gpio-%-3d (%-20.20s) %s %s %s",
2039 is_out ? "out" : "in ",
2041 ? (chip->get(chip, i) ? "hi" : "lo")
2043 is_irq ? "IRQ" : " ");
2044 seq_printf(s, "\n");
2048 static void *gpiolib_seq_start(struct seq_file *s, loff_t *pos)
2050 unsigned long flags;
2051 struct gpio_chip *chip = NULL;
2052 loff_t index = *pos;
2056 spin_lock_irqsave(&gpio_lock, flags);
2057 list_for_each_entry(chip, &gpio_chips, list)
2059 spin_unlock_irqrestore(&gpio_lock, flags);
2062 spin_unlock_irqrestore(&gpio_lock, flags);
2067 static void *gpiolib_seq_next(struct seq_file *s, void *v, loff_t *pos)
2069 unsigned long flags;
2070 struct gpio_chip *chip = v;
2073 spin_lock_irqsave(&gpio_lock, flags);
2074 if (list_is_last(&chip->list, &gpio_chips))
2077 ret = list_entry(chip->list.next, struct gpio_chip, list);
2078 spin_unlock_irqrestore(&gpio_lock, flags);
2086 static void gpiolib_seq_stop(struct seq_file *s, void *v)
2090 static int gpiolib_seq_show(struct seq_file *s, void *v)
2092 struct gpio_chip *chip = v;
2095 seq_printf(s, "%sGPIOs %d-%d", (char *)s->private,
2096 chip->base, chip->base + chip->ngpio - 1);
2099 seq_printf(s, ", %s/%s", dev->bus ? dev->bus->name : "no-bus",
2102 seq_printf(s, ", %s", chip->label);
2103 if (chip->can_sleep)
2104 seq_printf(s, ", can sleep");
2105 seq_printf(s, ":\n");
2108 chip->dbg_show(s, chip);
2110 gpiolib_dbg_show(s, chip);
2115 static const struct seq_operations gpiolib_seq_ops = {
2116 .start = gpiolib_seq_start,
2117 .next = gpiolib_seq_next,
2118 .stop = gpiolib_seq_stop,
2119 .show = gpiolib_seq_show,
2122 static int gpiolib_open(struct inode *inode, struct file *file)
2124 return seq_open(file, &gpiolib_seq_ops);
2127 static const struct file_operations gpiolib_operations = {
2128 .owner = THIS_MODULE,
2129 .open = gpiolib_open,
2131 .llseek = seq_lseek,
2132 .release = seq_release,
2135 static int __init gpiolib_debugfs_init(void)
2137 /* /sys/kernel/debug/gpio */
2138 (void) debugfs_create_file("gpio", S_IFREG | S_IRUGO,
2139 NULL, NULL, &gpiolib_operations);
2142 subsys_initcall(gpiolib_debugfs_init);
2144 #endif /* DEBUG_FS */