1 #include <linux/kernel.h>
2 #include <linux/module.h>
3 #include <linux/interrupt.h>
5 #include <linux/spinlock.h>
6 #include <linux/device.h>
8 #include <linux/debugfs.h>
9 #include <linux/seq_file.h>
10 #include <linux/gpio.h>
11 #include <linux/of_gpio.h>
12 #include <linux/idr.h>
13 #include <linux/slab.h>
15 #define CREATE_TRACE_POINTS
16 #include <trace/events/gpio.h>
18 /* Optional implementation infrastructure for GPIO interfaces.
20 * Platforms may want to use this if they tend to use very many GPIOs
21 * that aren't part of a System-On-Chip core; or across I2C/SPI/etc.
23 * When kernel footprint or instruction count is an issue, simpler
24 * implementations may be preferred. The GPIO programming interface
25 * allows for inlining speed-critical get/set operations for common
26 * cases, so that access to SOC-integrated GPIOs can sometimes cost
27 * only an instruction or two per bit.
31 /* When debugging, extend minimal trust to callers and platform code.
32 * Also emit diagnostic messages that may help initial bringup, when
33 * board setup or driver bugs are most common.
35 * Otherwise, minimize overhead in what may be bitbanging codepaths.
38 #define extra_checks 1
40 #define extra_checks 0
43 /* gpio_lock prevents conflicts during gpio_desc[] table updates.
44 * While any GPIO is requested, its gpio_chip is not removable;
45 * each GPIO's "requested" flag serves as a lock and refcount.
47 static DEFINE_SPINLOCK(gpio_lock);
50 struct gpio_chip *chip;
52 /* flag symbols are bit numbers */
53 #define FLAG_REQUESTED 0
55 #define FLAG_RESERVED 2
56 #define FLAG_EXPORT 3 /* protected by sysfs_lock */
57 #define FLAG_SYSFS 4 /* exported via /sys/class/gpio/control */
58 #define FLAG_TRIG_FALL 5 /* trigger on falling edge */
59 #define FLAG_TRIG_RISE 6 /* trigger on rising edge */
60 #define FLAG_ACTIVE_LOW 7 /* sysfs value has active low */
61 #define FLAG_OPEN_DRAIN 8 /* Gpio is open drain type */
62 #define FLAG_OPEN_SOURCE 9 /* Gpio is open source type */
64 #define ID_SHIFT 16 /* add new flags before this one */
66 #define GPIO_FLAGS_MASK ((1 << ID_SHIFT) - 1)
67 #define GPIO_TRIGGER_MASK (BIT(FLAG_TRIG_FALL) | BIT(FLAG_TRIG_RISE))
69 #ifdef CONFIG_DEBUG_FS
73 static struct gpio_desc gpio_desc[ARCH_NR_GPIOS];
75 #ifdef CONFIG_GPIO_SYSFS
76 static DEFINE_IDR(dirent_idr);
79 static inline void desc_set_label(struct gpio_desc *d, const char *label)
81 #ifdef CONFIG_DEBUG_FS
86 /* Warn when drivers omit gpio_request() calls -- legal but ill-advised
87 * when setting direction, and otherwise illegal. Until board setup code
88 * and drivers use explicit requests everywhere (which won't happen when
89 * those calls have no teeth) we can't avoid autorequesting. This nag
90 * message should motivate switching to explicit requests... so should
91 * the weaker cleanup after faults, compared to gpio_request().
93 * NOTE: the autorequest mechanism is going away; at this point it's
94 * only "legal" in the sense that (old) code using it won't break yet,
95 * but instead only triggers a WARN() stack dump.
97 static int gpio_ensure_requested(struct gpio_desc *desc, unsigned offset)
99 const struct gpio_chip *chip = desc->chip;
100 const int gpio = chip->base + offset;
102 if (WARN(test_and_set_bit(FLAG_REQUESTED, &desc->flags) == 0,
103 "autorequest GPIO-%d\n", gpio)) {
104 if (!try_module_get(chip->owner)) {
105 pr_err("GPIO-%d: module can't be gotten \n", gpio);
106 clear_bit(FLAG_REQUESTED, &desc->flags);
110 desc_set_label(desc, "[auto]");
111 /* caller must chip->request() w/o spinlock */
118 /* caller holds gpio_lock *OR* gpio is marked as requested */
119 struct gpio_chip *gpio_to_chip(unsigned gpio)
121 return gpio_desc[gpio].chip;
124 /* dynamic allocation of GPIOs, e.g. on a hotplugged device */
125 static int gpiochip_find_base(int ngpio)
131 for (i = ARCH_NR_GPIOS - 1; i >= 0 ; i--) {
132 struct gpio_desc *desc = &gpio_desc[i];
133 struct gpio_chip *chip = desc->chip;
135 if (!chip && !test_bit(FLAG_RESERVED, &desc->flags)) {
137 if (spare == ngpio) {
144 i -= chip->ngpio - 1;
148 if (gpio_is_valid(base))
149 pr_debug("%s: found new base at %d\n", __func__, base);
154 * gpiochip_reserve() - reserve range of gpios to use with platform code only
155 * @start: starting gpio number
156 * @ngpio: number of gpios to reserve
157 * Context: platform init, potentially before irqs or kmalloc will work
159 * Returns a negative errno if any gpio within the range is already reserved
160 * or registered, else returns zero as a success code. Use this function
161 * to mark a range of gpios as unavailable for dynamic gpio number allocation,
162 * for example because its driver support is not yet loaded.
164 int __init gpiochip_reserve(int start, int ngpio)
170 if (!gpio_is_valid(start) || !gpio_is_valid(start + ngpio - 1))
173 spin_lock_irqsave(&gpio_lock, flags);
175 for (i = start; i < start + ngpio; i++) {
176 struct gpio_desc *desc = &gpio_desc[i];
178 if (desc->chip || test_bit(FLAG_RESERVED, &desc->flags)) {
183 set_bit(FLAG_RESERVED, &desc->flags);
186 pr_debug("%s: reserved gpios from %d to %d\n",
187 __func__, start, start + ngpio - 1);
189 spin_unlock_irqrestore(&gpio_lock, flags);
194 #ifdef CONFIG_GPIO_SYSFS
196 /* lock protects against unexport_gpio() being called while
197 * sysfs files are active.
199 static DEFINE_MUTEX(sysfs_lock);
202 * /sys/class/gpio/gpioN... only for GPIOs that are exported
204 * * MAY BE OMITTED if kernel won't allow direction changes
205 * * is read/write as "in" or "out"
206 * * may also be written as "high" or "low", initializing
207 * output value as specified ("out" implies "low")
209 * * always readable, subject to hardware behavior
210 * * may be writable, as zero/nonzero
212 * * configures behavior of poll(2) on /value
213 * * available only if pin can generate IRQs on input
214 * * is read/write as "none", "falling", "rising", or "both"
216 * * configures polarity of /value
217 * * is read/write as zero/nonzero
218 * * also affects existing and subsequent "falling" and "rising"
219 * /edge configuration
222 static ssize_t gpio_direction_show(struct device *dev,
223 struct device_attribute *attr, char *buf)
225 const struct gpio_desc *desc = dev_get_drvdata(dev);
228 mutex_lock(&sysfs_lock);
230 if (!test_bit(FLAG_EXPORT, &desc->flags))
233 status = sprintf(buf, "%s\n",
234 test_bit(FLAG_IS_OUT, &desc->flags)
237 mutex_unlock(&sysfs_lock);
241 static ssize_t gpio_direction_store(struct device *dev,
242 struct device_attribute *attr, const char *buf, size_t size)
244 const struct gpio_desc *desc = dev_get_drvdata(dev);
245 unsigned gpio = desc - gpio_desc;
248 mutex_lock(&sysfs_lock);
250 if (!test_bit(FLAG_EXPORT, &desc->flags))
252 else if (sysfs_streq(buf, "high"))
253 status = gpio_direction_output(gpio, 1);
254 else if (sysfs_streq(buf, "out") || sysfs_streq(buf, "low"))
255 status = gpio_direction_output(gpio, 0);
256 else if (sysfs_streq(buf, "in"))
257 status = gpio_direction_input(gpio);
261 mutex_unlock(&sysfs_lock);
262 return status ? : size;
265 static /* const */ DEVICE_ATTR(direction, 0644,
266 gpio_direction_show, gpio_direction_store);
268 static ssize_t gpio_value_show(struct device *dev,
269 struct device_attribute *attr, char *buf)
271 const struct gpio_desc *desc = dev_get_drvdata(dev);
272 unsigned gpio = desc - gpio_desc;
275 mutex_lock(&sysfs_lock);
277 if (!test_bit(FLAG_EXPORT, &desc->flags)) {
282 value = !!gpio_get_value_cansleep(gpio);
283 if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
286 status = sprintf(buf, "%d\n", value);
289 mutex_unlock(&sysfs_lock);
293 static ssize_t gpio_value_store(struct device *dev,
294 struct device_attribute *attr, const char *buf, size_t size)
296 const struct gpio_desc *desc = dev_get_drvdata(dev);
297 unsigned gpio = desc - gpio_desc;
300 mutex_lock(&sysfs_lock);
302 if (!test_bit(FLAG_EXPORT, &desc->flags))
304 else if (!test_bit(FLAG_IS_OUT, &desc->flags))
309 status = strict_strtol(buf, 0, &value);
311 if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
313 gpio_set_value_cansleep(gpio, value != 0);
318 mutex_unlock(&sysfs_lock);
322 static const DEVICE_ATTR(value, 0644,
323 gpio_value_show, gpio_value_store);
325 static irqreturn_t gpio_sysfs_irq(int irq, void *priv)
327 struct sysfs_dirent *value_sd = priv;
329 sysfs_notify_dirent(value_sd);
333 static int gpio_setup_irq(struct gpio_desc *desc, struct device *dev,
334 unsigned long gpio_flags)
336 struct sysfs_dirent *value_sd;
337 unsigned long irq_flags;
340 if ((desc->flags & GPIO_TRIGGER_MASK) == gpio_flags)
343 irq = gpio_to_irq(desc - gpio_desc);
347 id = desc->flags >> ID_SHIFT;
348 value_sd = idr_find(&dirent_idr, id);
350 free_irq(irq, value_sd);
352 desc->flags &= ~GPIO_TRIGGER_MASK;
359 irq_flags = IRQF_SHARED;
360 if (test_bit(FLAG_TRIG_FALL, &gpio_flags))
361 irq_flags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ?
362 IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING;
363 if (test_bit(FLAG_TRIG_RISE, &gpio_flags))
364 irq_flags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ?
365 IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING;
368 value_sd = sysfs_get_dirent(dev->kobj.sd, NULL, "value");
376 if (idr_pre_get(&dirent_idr, GFP_KERNEL))
377 ret = idr_get_new_above(&dirent_idr, value_sd,
379 } while (ret == -EAGAIN);
384 desc->flags &= GPIO_FLAGS_MASK;
385 desc->flags |= (unsigned long)id << ID_SHIFT;
387 if (desc->flags >> ID_SHIFT != id) {
393 ret = request_any_context_irq(irq, gpio_sysfs_irq, irq_flags,
394 "gpiolib", value_sd);
398 desc->flags |= gpio_flags;
402 idr_remove(&dirent_idr, id);
403 desc->flags &= GPIO_FLAGS_MASK;
411 static const struct {
414 } trigger_types[] = {
416 { "falling", BIT(FLAG_TRIG_FALL) },
417 { "rising", BIT(FLAG_TRIG_RISE) },
418 { "both", BIT(FLAG_TRIG_FALL) | BIT(FLAG_TRIG_RISE) },
421 static ssize_t gpio_edge_show(struct device *dev,
422 struct device_attribute *attr, char *buf)
424 const struct gpio_desc *desc = dev_get_drvdata(dev);
427 mutex_lock(&sysfs_lock);
429 if (!test_bit(FLAG_EXPORT, &desc->flags))
435 for (i = 0; i < ARRAY_SIZE(trigger_types); i++)
436 if ((desc->flags & GPIO_TRIGGER_MASK)
437 == trigger_types[i].flags) {
438 status = sprintf(buf, "%s\n",
439 trigger_types[i].name);
444 mutex_unlock(&sysfs_lock);
448 static ssize_t gpio_edge_store(struct device *dev,
449 struct device_attribute *attr, const char *buf, size_t size)
451 struct gpio_desc *desc = dev_get_drvdata(dev);
455 for (i = 0; i < ARRAY_SIZE(trigger_types); i++)
456 if (sysfs_streq(trigger_types[i].name, buf))
461 mutex_lock(&sysfs_lock);
463 if (!test_bit(FLAG_EXPORT, &desc->flags))
466 status = gpio_setup_irq(desc, dev, trigger_types[i].flags);
471 mutex_unlock(&sysfs_lock);
476 static DEVICE_ATTR(edge, 0644, gpio_edge_show, gpio_edge_store);
478 static int sysfs_set_active_low(struct gpio_desc *desc, struct device *dev,
483 if (!!test_bit(FLAG_ACTIVE_LOW, &desc->flags) == !!value)
487 set_bit(FLAG_ACTIVE_LOW, &desc->flags);
489 clear_bit(FLAG_ACTIVE_LOW, &desc->flags);
491 /* reconfigure poll(2) support if enabled on one edge only */
492 if (dev != NULL && (!!test_bit(FLAG_TRIG_RISE, &desc->flags) ^
493 !!test_bit(FLAG_TRIG_FALL, &desc->flags))) {
494 unsigned long trigger_flags = desc->flags & GPIO_TRIGGER_MASK;
496 gpio_setup_irq(desc, dev, 0);
497 status = gpio_setup_irq(desc, dev, trigger_flags);
503 static ssize_t gpio_active_low_show(struct device *dev,
504 struct device_attribute *attr, char *buf)
506 const struct gpio_desc *desc = dev_get_drvdata(dev);
509 mutex_lock(&sysfs_lock);
511 if (!test_bit(FLAG_EXPORT, &desc->flags))
514 status = sprintf(buf, "%d\n",
515 !!test_bit(FLAG_ACTIVE_LOW, &desc->flags));
517 mutex_unlock(&sysfs_lock);
522 static ssize_t gpio_active_low_store(struct device *dev,
523 struct device_attribute *attr, const char *buf, size_t size)
525 struct gpio_desc *desc = dev_get_drvdata(dev);
528 mutex_lock(&sysfs_lock);
530 if (!test_bit(FLAG_EXPORT, &desc->flags)) {
535 status = strict_strtol(buf, 0, &value);
537 status = sysfs_set_active_low(desc, dev, value != 0);
540 mutex_unlock(&sysfs_lock);
542 return status ? : size;
545 static const DEVICE_ATTR(active_low, 0644,
546 gpio_active_low_show, gpio_active_low_store);
548 static const struct attribute *gpio_attrs[] = {
549 &dev_attr_value.attr,
550 &dev_attr_active_low.attr,
554 static const struct attribute_group gpio_attr_group = {
555 .attrs = (struct attribute **) gpio_attrs,
559 * /sys/class/gpio/gpiochipN/
560 * /base ... matching gpio_chip.base (N)
561 * /label ... matching gpio_chip.label
562 * /ngpio ... matching gpio_chip.ngpio
565 static ssize_t chip_base_show(struct device *dev,
566 struct device_attribute *attr, char *buf)
568 const struct gpio_chip *chip = dev_get_drvdata(dev);
570 return sprintf(buf, "%d\n", chip->base);
572 static DEVICE_ATTR(base, 0444, chip_base_show, NULL);
574 static ssize_t chip_label_show(struct device *dev,
575 struct device_attribute *attr, char *buf)
577 const struct gpio_chip *chip = dev_get_drvdata(dev);
579 return sprintf(buf, "%s\n", chip->label ? : "");
581 static DEVICE_ATTR(label, 0444, chip_label_show, NULL);
583 static ssize_t chip_ngpio_show(struct device *dev,
584 struct device_attribute *attr, char *buf)
586 const struct gpio_chip *chip = dev_get_drvdata(dev);
588 return sprintf(buf, "%u\n", chip->ngpio);
590 static DEVICE_ATTR(ngpio, 0444, chip_ngpio_show, NULL);
592 static const struct attribute *gpiochip_attrs[] = {
594 &dev_attr_label.attr,
595 &dev_attr_ngpio.attr,
599 static const struct attribute_group gpiochip_attr_group = {
600 .attrs = (struct attribute **) gpiochip_attrs,
604 * /sys/class/gpio/export ... write-only
605 * integer N ... number of GPIO to export (full access)
606 * /sys/class/gpio/unexport ... write-only
607 * integer N ... number of GPIO to unexport
609 static ssize_t export_store(struct class *class,
610 struct class_attribute *attr,
611 const char *buf, size_t len)
616 status = strict_strtol(buf, 0, &gpio);
620 /* No extra locking here; FLAG_SYSFS just signifies that the
621 * request and export were done by on behalf of userspace, so
622 * they may be undone on its behalf too.
625 status = gpio_request(gpio, "sysfs");
627 if (status == -EPROBE_DEFER)
631 status = gpio_export(gpio, true);
635 set_bit(FLAG_SYSFS, &gpio_desc[gpio].flags);
639 pr_debug("%s: status %d\n", __func__, status);
640 return status ? : len;
643 static ssize_t unexport_store(struct class *class,
644 struct class_attribute *attr,
645 const char *buf, size_t len)
650 status = strict_strtol(buf, 0, &gpio);
656 /* reject bogus commands (gpio_unexport ignores them) */
657 if (!gpio_is_valid(gpio))
660 /* No extra locking here; FLAG_SYSFS just signifies that the
661 * request and export were done by on behalf of userspace, so
662 * they may be undone on its behalf too.
664 if (test_and_clear_bit(FLAG_SYSFS, &gpio_desc[gpio].flags)) {
670 pr_debug("%s: status %d\n", __func__, status);
671 return status ? : len;
674 static struct class_attribute gpio_class_attrs[] = {
675 __ATTR(export, 0200, NULL, export_store),
676 __ATTR(unexport, 0200, NULL, unexport_store),
680 static struct class gpio_class = {
682 .owner = THIS_MODULE,
684 .class_attrs = gpio_class_attrs,
689 * gpio_export - export a GPIO through sysfs
690 * @gpio: gpio to make available, already requested
691 * @direction_may_change: true if userspace may change gpio direction
692 * Context: arch_initcall or later
694 * When drivers want to make a GPIO accessible to userspace after they
695 * have requested it -- perhaps while debugging, or as part of their
696 * public interface -- they may use this routine. If the GPIO can
697 * change direction (some can't) and the caller allows it, userspace
698 * will see "direction" sysfs attribute which may be used to change
699 * the gpio's direction. A "value" attribute will always be provided.
701 * Returns zero on success, else an error.
703 int gpio_export(unsigned gpio, bool direction_may_change)
706 struct gpio_desc *desc;
707 int status = -EINVAL;
708 const char *ioname = NULL;
710 /* can't export until sysfs is available ... */
712 pr_debug("%s: called too early!\n", __func__);
716 if (!gpio_is_valid(gpio))
719 mutex_lock(&sysfs_lock);
721 spin_lock_irqsave(&gpio_lock, flags);
722 desc = &gpio_desc[gpio];
723 if (test_bit(FLAG_REQUESTED, &desc->flags)
724 && !test_bit(FLAG_EXPORT, &desc->flags)) {
726 if (!desc->chip->direction_input
727 || !desc->chip->direction_output)
728 direction_may_change = false;
730 spin_unlock_irqrestore(&gpio_lock, flags);
732 if (desc->chip->names && desc->chip->names[gpio - desc->chip->base])
733 ioname = desc->chip->names[gpio - desc->chip->base];
738 dev = device_create(&gpio_class, desc->chip->dev, MKDEV(0, 0),
739 desc, ioname ? ioname : "gpio%u", gpio);
741 status = sysfs_create_group(&dev->kobj,
744 if (!status && direction_may_change)
745 status = device_create_file(dev,
746 &dev_attr_direction);
748 if (!status && gpio_to_irq(gpio) >= 0
749 && (direction_may_change
750 || !test_bit(FLAG_IS_OUT,
752 status = device_create_file(dev,
756 device_unregister(dev);
758 status = PTR_ERR(dev);
760 set_bit(FLAG_EXPORT, &desc->flags);
763 mutex_unlock(&sysfs_lock);
767 pr_debug("%s: gpio%d status %d\n", __func__, gpio, status);
771 EXPORT_SYMBOL_GPL(gpio_export);
773 static int match_export(struct device *dev, void *data)
775 return dev_get_drvdata(dev) == data;
779 * gpio_export_link - create a sysfs link to an exported GPIO node
780 * @dev: device under which to create symlink
781 * @name: name of the symlink
782 * @gpio: gpio to create symlink to, already exported
784 * Set up a symlink from /sys/.../dev/name to /sys/class/gpio/gpioN
785 * node. Caller is responsible for unlinking.
787 * Returns zero on success, else an error.
789 int gpio_export_link(struct device *dev, const char *name, unsigned gpio)
791 struct gpio_desc *desc;
792 int status = -EINVAL;
794 if (!gpio_is_valid(gpio))
797 mutex_lock(&sysfs_lock);
799 desc = &gpio_desc[gpio];
801 if (test_bit(FLAG_EXPORT, &desc->flags)) {
804 tdev = class_find_device(&gpio_class, NULL, desc, match_export);
806 status = sysfs_create_link(&dev->kobj, &tdev->kobj,
813 mutex_unlock(&sysfs_lock);
817 pr_debug("%s: gpio%d status %d\n", __func__, gpio, status);
821 EXPORT_SYMBOL_GPL(gpio_export_link);
825 * gpio_sysfs_set_active_low - set the polarity of gpio sysfs value
826 * @gpio: gpio to change
827 * @value: non-zero to use active low, i.e. inverted values
829 * Set the polarity of /sys/class/gpio/gpioN/value sysfs attribute.
830 * The GPIO does not have to be exported yet. If poll(2) support has
831 * been enabled for either rising or falling edge, it will be
832 * reconfigured to follow the new polarity.
834 * Returns zero on success, else an error.
836 int gpio_sysfs_set_active_low(unsigned gpio, int value)
838 struct gpio_desc *desc;
839 struct device *dev = NULL;
840 int status = -EINVAL;
842 if (!gpio_is_valid(gpio))
845 mutex_lock(&sysfs_lock);
847 desc = &gpio_desc[gpio];
849 if (test_bit(FLAG_EXPORT, &desc->flags)) {
850 dev = class_find_device(&gpio_class, NULL, desc, match_export);
857 status = sysfs_set_active_low(desc, dev, value);
860 mutex_unlock(&sysfs_lock);
864 pr_debug("%s: gpio%d status %d\n", __func__, gpio, status);
868 EXPORT_SYMBOL_GPL(gpio_sysfs_set_active_low);
871 * gpio_unexport - reverse effect of gpio_export()
872 * @gpio: gpio to make unavailable
874 * This is implicit on gpio_free().
876 void gpio_unexport(unsigned gpio)
878 struct gpio_desc *desc;
880 struct device *dev = NULL;
882 if (!gpio_is_valid(gpio)) {
887 mutex_lock(&sysfs_lock);
889 desc = &gpio_desc[gpio];
891 if (test_bit(FLAG_EXPORT, &desc->flags)) {
893 dev = class_find_device(&gpio_class, NULL, desc, match_export);
895 gpio_setup_irq(desc, dev, 0);
896 clear_bit(FLAG_EXPORT, &desc->flags);
901 mutex_unlock(&sysfs_lock);
903 device_unregister(dev);
908 pr_debug("%s: gpio%d status %d\n", __func__, gpio, status);
910 EXPORT_SYMBOL_GPL(gpio_unexport);
912 static int gpiochip_export(struct gpio_chip *chip)
917 /* Many systems register gpio chips for SOC support very early,
918 * before driver model support is available. In those cases we
919 * export this later, in gpiolib_sysfs_init() ... here we just
920 * verify that _some_ field of gpio_class got initialized.
925 /* use chip->base for the ID; it's already known to be unique */
926 mutex_lock(&sysfs_lock);
927 dev = device_create(&gpio_class, chip->dev, MKDEV(0, 0), chip,
928 "gpiochip%d", chip->base);
930 status = sysfs_create_group(&dev->kobj,
931 &gpiochip_attr_group);
933 status = PTR_ERR(dev);
934 chip->exported = (status == 0);
935 mutex_unlock(&sysfs_lock);
941 spin_lock_irqsave(&gpio_lock, flags);
943 while (gpio_desc[gpio].chip == chip)
944 gpio_desc[gpio++].chip = NULL;
945 spin_unlock_irqrestore(&gpio_lock, flags);
947 pr_debug("%s: chip %s status %d\n", __func__,
948 chip->label, status);
954 static void gpiochip_unexport(struct gpio_chip *chip)
959 mutex_lock(&sysfs_lock);
960 dev = class_find_device(&gpio_class, NULL, chip, match_export);
963 device_unregister(dev);
968 mutex_unlock(&sysfs_lock);
971 pr_debug("%s: chip %s status %d\n", __func__,
972 chip->label, status);
975 static int __init gpiolib_sysfs_init(void)
981 status = class_register(&gpio_class);
985 /* Scan and register the gpio_chips which registered very
986 * early (e.g. before the class_register above was called).
988 * We run before arch_initcall() so chip->dev nodes can have
989 * registered, and so arch_initcall() can always gpio_export().
991 spin_lock_irqsave(&gpio_lock, flags);
992 for (gpio = 0; gpio < ARCH_NR_GPIOS; gpio++) {
993 struct gpio_chip *chip;
995 chip = gpio_desc[gpio].chip;
996 if (!chip || chip->exported)
999 spin_unlock_irqrestore(&gpio_lock, flags);
1000 status = gpiochip_export(chip);
1001 spin_lock_irqsave(&gpio_lock, flags);
1003 spin_unlock_irqrestore(&gpio_lock, flags);
1008 postcore_initcall(gpiolib_sysfs_init);
1011 static inline int gpiochip_export(struct gpio_chip *chip)
1016 static inline void gpiochip_unexport(struct gpio_chip *chip)
1020 #endif /* CONFIG_GPIO_SYSFS */
1023 * gpiochip_add() - register a gpio_chip
1024 * @chip: the chip to register, with chip->base initialized
1025 * Context: potentially before irqs or kmalloc will work
1027 * Returns a negative errno if the chip can't be registered, such as
1028 * because the chip->base is invalid or already associated with a
1029 * different chip. Otherwise it returns zero as a success code.
1031 * When gpiochip_add() is called very early during boot, so that GPIOs
1032 * can be freely used, the chip->dev device must be registered before
1033 * the gpio framework's arch_initcall(). Otherwise sysfs initialization
1034 * for GPIOs will fail rudely.
1036 * If chip->base is negative, this requests dynamic assignment of
1037 * a range of valid GPIOs.
1039 int gpiochip_add(struct gpio_chip *chip)
1041 unsigned long flags;
1044 int base = chip->base;
1046 if ((!gpio_is_valid(base) || !gpio_is_valid(base + chip->ngpio - 1))
1052 spin_lock_irqsave(&gpio_lock, flags);
1055 base = gpiochip_find_base(chip->ngpio);
1063 /* these GPIO numbers must not be managed by another gpio_chip */
1064 for (id = base; id < base + chip->ngpio; id++) {
1065 if (gpio_desc[id].chip != NULL) {
1071 for (id = base; id < base + chip->ngpio; id++) {
1072 gpio_desc[id].chip = chip;
1074 /* REVISIT: most hardware initializes GPIOs as
1075 * inputs (often with pullups enabled) so power
1076 * usage is minimized. Linux code should set the
1077 * gpio direction first thing; but until it does,
1078 * we may expose the wrong direction in sysfs.
1080 gpio_desc[id].flags = !chip->direction_input
1081 ? (1 << FLAG_IS_OUT)
1086 #ifdef CONFIG_PINCTRL
1087 INIT_LIST_HEAD(&chip->pin_ranges);
1090 of_gpiochip_add(chip);
1093 spin_unlock_irqrestore(&gpio_lock, flags);
1098 status = gpiochip_export(chip);
1102 pr_debug("gpiochip_add: registered GPIOs %d to %d on device: %s\n",
1103 chip->base, chip->base + chip->ngpio - 1,
1104 chip->label ? : "generic");
1108 /* failures here can mean systems won't boot... */
1109 pr_err("gpiochip_add: gpios %d..%d (%s) failed to register\n",
1110 chip->base, chip->base + chip->ngpio - 1,
1111 chip->label ? : "generic");
1114 EXPORT_SYMBOL_GPL(gpiochip_add);
1117 * gpiochip_remove() - unregister a gpio_chip
1118 * @chip: the chip to unregister
1120 * A gpio_chip with any GPIOs still requested may not be removed.
1122 int gpiochip_remove(struct gpio_chip *chip)
1124 unsigned long flags;
1128 spin_lock_irqsave(&gpio_lock, flags);
1130 gpiochip_remove_pin_ranges(chip);
1131 of_gpiochip_remove(chip);
1133 for (id = chip->base; id < chip->base + chip->ngpio; id++) {
1134 if (test_bit(FLAG_REQUESTED, &gpio_desc[id].flags)) {
1140 for (id = chip->base; id < chip->base + chip->ngpio; id++)
1141 gpio_desc[id].chip = NULL;
1144 spin_unlock_irqrestore(&gpio_lock, flags);
1147 gpiochip_unexport(chip);
1151 EXPORT_SYMBOL_GPL(gpiochip_remove);
1154 * gpiochip_find() - iterator for locating a specific gpio_chip
1155 * @data: data to pass to match function
1156 * @callback: Callback function to check gpio_chip
1158 * Similar to bus_find_device. It returns a reference to a gpio_chip as
1159 * determined by a user supplied @match callback. The callback should return
1160 * 0 if the device doesn't match and non-zero if it does. If the callback is
1161 * non-zero, this function will return to the caller and not iterate over any
1164 struct gpio_chip *gpiochip_find(void *data,
1165 int (*match)(struct gpio_chip *chip,
1168 struct gpio_chip *chip = NULL;
1169 unsigned long flags;
1172 spin_lock_irqsave(&gpio_lock, flags);
1173 for (i = 0; i < ARCH_NR_GPIOS; i++) {
1174 if (!gpio_desc[i].chip)
1177 if (match(gpio_desc[i].chip, data)) {
1178 chip = gpio_desc[i].chip;
1182 spin_unlock_irqrestore(&gpio_lock, flags);
1186 EXPORT_SYMBOL_GPL(gpiochip_find);
1188 #ifdef CONFIG_PINCTRL
1190 int gpiochip_add_pin_range(struct gpio_chip *chip, const char *pinctl_name,
1191 unsigned int pin_base, unsigned int npins)
1193 struct gpio_pin_range *pin_range;
1195 pin_range = devm_kzalloc(chip->dev, sizeof(*pin_range), GFP_KERNEL);
1197 pr_err("%s: GPIO chip: failed to allocate pin ranges\n",
1202 pin_range->range.name = chip->label;
1203 pin_range->range.base = chip->base;
1204 pin_range->range.pin_base = pin_base;
1205 pin_range->range.npins = npins;
1206 pin_range->pctldev = find_pinctrl_and_add_gpio_range(pinctl_name,
1209 list_add_tail(&pin_range->node, &chip->pin_ranges);
1213 EXPORT_SYMBOL_GPL(gpiochip_add_pin_range);
1215 void gpiochip_remove_pin_ranges(struct gpio_chip *chip)
1217 struct gpio_pin_range *pin_range, *tmp;
1219 list_for_each_entry_safe(pin_range, tmp, &chip->pin_ranges, node) {
1220 list_del(&pin_range->node);
1221 pinctrl_remove_gpio_range(pin_range->pctldev,
1225 EXPORT_SYMBOL_GPL(gpiochip_remove_pin_ranges);
1227 #endif /* CONFIG_PINCTRL */
1229 /* These "optional" allocation calls help prevent drivers from stomping
1230 * on each other, and help provide better diagnostics in debugfs.
1231 * They're called even less than the "set direction" calls.
1233 int gpio_request(unsigned gpio, const char *label)
1235 struct gpio_desc *desc;
1236 struct gpio_chip *chip;
1237 int status = -EPROBE_DEFER;
1238 unsigned long flags;
1240 spin_lock_irqsave(&gpio_lock, flags);
1242 if (!gpio_is_valid(gpio)) {
1246 desc = &gpio_desc[gpio];
1251 if (!try_module_get(chip->owner))
1254 /* NOTE: gpio_request() can be called in early boot,
1255 * before IRQs are enabled, for non-sleeping (SOC) GPIOs.
1258 if (test_and_set_bit(FLAG_REQUESTED, &desc->flags) == 0) {
1259 desc_set_label(desc, label ? : "?");
1263 module_put(chip->owner);
1267 if (chip->request) {
1268 /* chip->request may sleep */
1269 spin_unlock_irqrestore(&gpio_lock, flags);
1270 status = chip->request(chip, gpio - chip->base);
1271 spin_lock_irqsave(&gpio_lock, flags);
1274 desc_set_label(desc, NULL);
1275 module_put(chip->owner);
1276 clear_bit(FLAG_REQUESTED, &desc->flags);
1282 pr_debug("gpio_request: gpio-%d (%s) status %d\n",
1283 gpio, label ? : "?", status);
1284 spin_unlock_irqrestore(&gpio_lock, flags);
1287 EXPORT_SYMBOL_GPL(gpio_request);
1289 void gpio_free(unsigned gpio)
1291 unsigned long flags;
1292 struct gpio_desc *desc;
1293 struct gpio_chip *chip;
1297 if (!gpio_is_valid(gpio)) {
1298 WARN_ON(extra_checks);
1302 gpio_unexport(gpio);
1304 spin_lock_irqsave(&gpio_lock, flags);
1306 desc = &gpio_desc[gpio];
1308 if (chip && test_bit(FLAG_REQUESTED, &desc->flags)) {
1310 spin_unlock_irqrestore(&gpio_lock, flags);
1311 might_sleep_if(chip->can_sleep);
1312 chip->free(chip, gpio - chip->base);
1313 spin_lock_irqsave(&gpio_lock, flags);
1315 desc_set_label(desc, NULL);
1316 module_put(desc->chip->owner);
1317 clear_bit(FLAG_ACTIVE_LOW, &desc->flags);
1318 clear_bit(FLAG_REQUESTED, &desc->flags);
1319 clear_bit(FLAG_OPEN_DRAIN, &desc->flags);
1320 clear_bit(FLAG_OPEN_SOURCE, &desc->flags);
1322 WARN_ON(extra_checks);
1324 spin_unlock_irqrestore(&gpio_lock, flags);
1326 EXPORT_SYMBOL_GPL(gpio_free);
1329 * gpio_request_one - request a single GPIO with initial configuration
1330 * @gpio: the GPIO number
1331 * @flags: GPIO configuration as specified by GPIOF_*
1332 * @label: a literal description string of this GPIO
1334 int gpio_request_one(unsigned gpio, unsigned long flags, const char *label)
1338 err = gpio_request(gpio, label);
1342 if (flags & GPIOF_OPEN_DRAIN)
1343 set_bit(FLAG_OPEN_DRAIN, &gpio_desc[gpio].flags);
1345 if (flags & GPIOF_OPEN_SOURCE)
1346 set_bit(FLAG_OPEN_SOURCE, &gpio_desc[gpio].flags);
1348 if (flags & GPIOF_DIR_IN)
1349 err = gpio_direction_input(gpio);
1351 err = gpio_direction_output(gpio,
1352 (flags & GPIOF_INIT_HIGH) ? 1 : 0);
1357 if (flags & GPIOF_EXPORT) {
1358 err = gpio_export(gpio, flags & GPIOF_EXPORT_CHANGEABLE);
1369 EXPORT_SYMBOL_GPL(gpio_request_one);
1372 * gpio_request_array - request multiple GPIOs in a single call
1373 * @array: array of the 'struct gpio'
1374 * @num: how many GPIOs in the array
1376 int gpio_request_array(const struct gpio *array, size_t num)
1380 for (i = 0; i < num; i++, array++) {
1381 err = gpio_request_one(array->gpio, array->flags, array->label);
1389 gpio_free((--array)->gpio);
1392 EXPORT_SYMBOL_GPL(gpio_request_array);
1395 * gpio_free_array - release multiple GPIOs in a single call
1396 * @array: array of the 'struct gpio'
1397 * @num: how many GPIOs in the array
1399 void gpio_free_array(const struct gpio *array, size_t num)
1402 gpio_free((array++)->gpio);
1404 EXPORT_SYMBOL_GPL(gpio_free_array);
1407 * gpiochip_is_requested - return string iff signal was requested
1408 * @chip: controller managing the signal
1409 * @offset: of signal within controller's 0..(ngpio - 1) range
1411 * Returns NULL if the GPIO is not currently requested, else a string.
1412 * If debugfs support is enabled, the string returned is the label passed
1413 * to gpio_request(); otherwise it is a meaningless constant.
1415 * This function is for use by GPIO controller drivers. The label can
1416 * help with diagnostics, and knowing that the signal is used as a GPIO
1417 * can help avoid accidentally multiplexing it to another controller.
1419 const char *gpiochip_is_requested(struct gpio_chip *chip, unsigned offset)
1421 unsigned gpio = chip->base + offset;
1423 if (!gpio_is_valid(gpio) || gpio_desc[gpio].chip != chip)
1425 if (test_bit(FLAG_REQUESTED, &gpio_desc[gpio].flags) == 0)
1427 #ifdef CONFIG_DEBUG_FS
1428 return gpio_desc[gpio].label;
1433 EXPORT_SYMBOL_GPL(gpiochip_is_requested);
1436 /* Drivers MUST set GPIO direction before making get/set calls. In
1437 * some cases this is done in early boot, before IRQs are enabled.
1439 * As a rule these aren't called more than once (except for drivers
1440 * using the open-drain emulation idiom) so these are natural places
1441 * to accumulate extra debugging checks. Note that we can't (yet)
1442 * rely on gpio_request() having been called beforehand.
1445 int gpio_direction_input(unsigned gpio)
1447 unsigned long flags;
1448 struct gpio_chip *chip;
1449 struct gpio_desc *desc = &gpio_desc[gpio];
1450 int status = -EINVAL;
1452 spin_lock_irqsave(&gpio_lock, flags);
1454 if (!gpio_is_valid(gpio))
1457 if (!chip || !chip->get || !chip->direction_input)
1460 if (gpio >= chip->ngpio)
1462 status = gpio_ensure_requested(desc, gpio);
1466 /* now we know the gpio is valid and chip won't vanish */
1468 spin_unlock_irqrestore(&gpio_lock, flags);
1470 might_sleep_if(chip->can_sleep);
1473 status = chip->request(chip, gpio);
1475 pr_debug("GPIO-%d: chip request fail, %d\n",
1476 chip->base + gpio, status);
1477 /* and it's not available to anyone else ...
1478 * gpio_request() is the fully clean solution.
1484 status = chip->direction_input(chip, gpio);
1486 clear_bit(FLAG_IS_OUT, &desc->flags);
1488 trace_gpio_direction(chip->base + gpio, 1, status);
1492 spin_unlock_irqrestore(&gpio_lock, flags);
1494 pr_debug("%s: gpio-%d status %d\n",
1495 __func__, gpio, status);
1498 EXPORT_SYMBOL_GPL(gpio_direction_input);
1500 int gpio_direction_output(unsigned gpio, int value)
1502 unsigned long flags;
1503 struct gpio_chip *chip;
1504 struct gpio_desc *desc = &gpio_desc[gpio];
1505 int status = -EINVAL;
1507 /* Open drain pin should not be driven to 1 */
1508 if (value && test_bit(FLAG_OPEN_DRAIN, &desc->flags))
1509 return gpio_direction_input(gpio);
1511 /* Open source pin should not be driven to 0 */
1512 if (!value && test_bit(FLAG_OPEN_SOURCE, &desc->flags))
1513 return gpio_direction_input(gpio);
1515 spin_lock_irqsave(&gpio_lock, flags);
1517 if (!gpio_is_valid(gpio))
1520 if (!chip || !chip->set || !chip->direction_output)
1523 if (gpio >= chip->ngpio)
1525 status = gpio_ensure_requested(desc, gpio);
1529 /* now we know the gpio is valid and chip won't vanish */
1531 spin_unlock_irqrestore(&gpio_lock, flags);
1533 might_sleep_if(chip->can_sleep);
1536 status = chip->request(chip, gpio);
1538 pr_debug("GPIO-%d: chip request fail, %d\n",
1539 chip->base + gpio, status);
1540 /* and it's not available to anyone else ...
1541 * gpio_request() is the fully clean solution.
1547 status = chip->direction_output(chip, gpio, value);
1549 set_bit(FLAG_IS_OUT, &desc->flags);
1550 trace_gpio_value(chip->base + gpio, 0, value);
1551 trace_gpio_direction(chip->base + gpio, 0, status);
1555 spin_unlock_irqrestore(&gpio_lock, flags);
1557 pr_debug("%s: gpio-%d status %d\n",
1558 __func__, gpio, status);
1561 EXPORT_SYMBOL_GPL(gpio_direction_output);
1564 * gpio_set_debounce - sets @debounce time for a @gpio
1565 * @gpio: the gpio to set debounce time
1566 * @debounce: debounce time is microseconds
1568 int gpio_set_debounce(unsigned gpio, unsigned debounce)
1570 unsigned long flags;
1571 struct gpio_chip *chip;
1572 struct gpio_desc *desc = &gpio_desc[gpio];
1573 int status = -EINVAL;
1575 spin_lock_irqsave(&gpio_lock, flags);
1577 if (!gpio_is_valid(gpio))
1580 if (!chip || !chip->set || !chip->set_debounce)
1583 if (gpio >= chip->ngpio)
1585 status = gpio_ensure_requested(desc, gpio);
1589 /* now we know the gpio is valid and chip won't vanish */
1591 spin_unlock_irqrestore(&gpio_lock, flags);
1593 might_sleep_if(chip->can_sleep);
1595 return chip->set_debounce(chip, gpio, debounce);
1598 spin_unlock_irqrestore(&gpio_lock, flags);
1600 pr_debug("%s: gpio-%d status %d\n",
1601 __func__, gpio, status);
1605 EXPORT_SYMBOL_GPL(gpio_set_debounce);
1607 /* I/O calls are only valid after configuration completed; the relevant
1608 * "is this a valid GPIO" error checks should already have been done.
1610 * "Get" operations are often inlinable as reading a pin value register,
1611 * and masking the relevant bit in that register.
1613 * When "set" operations are inlinable, they involve writing that mask to
1614 * one register to set a low value, or a different register to set it high.
1615 * Otherwise locking is needed, so there may be little value to inlining.
1617 *------------------------------------------------------------------------
1619 * IMPORTANT!!! The hot paths -- get/set value -- assume that callers
1620 * have requested the GPIO. That can include implicit requesting by
1621 * a direction setting call. Marking a gpio as requested locks its chip
1622 * in memory, guaranteeing that these table lookups need no more locking
1623 * and that gpiochip_remove() will fail.
1625 * REVISIT when debugging, consider adding some instrumentation to ensure
1626 * that the GPIO was actually requested.
1630 * __gpio_get_value() - return a gpio's value
1631 * @gpio: gpio whose value will be returned
1634 * This is used directly or indirectly to implement gpio_get_value().
1635 * It returns the zero or nonzero value provided by the associated
1636 * gpio_chip.get() method; or zero if no such method is provided.
1638 int __gpio_get_value(unsigned gpio)
1640 struct gpio_chip *chip;
1643 chip = gpio_to_chip(gpio);
1644 /* Should be using gpio_get_value_cansleep() */
1645 WARN_ON(chip->can_sleep);
1646 value = chip->get ? chip->get(chip, gpio - chip->base) : 0;
1647 trace_gpio_value(gpio, 1, value);
1650 EXPORT_SYMBOL_GPL(__gpio_get_value);
1653 * _gpio_set_open_drain_value() - Set the open drain gpio's value.
1654 * @gpio: Gpio whose state need to be set.
1656 * @value: Non-zero for setting it HIGH otherise it will set to LOW.
1658 static void _gpio_set_open_drain_value(unsigned gpio,
1659 struct gpio_chip *chip, int value)
1663 err = chip->direction_input(chip, gpio - chip->base);
1665 clear_bit(FLAG_IS_OUT, &gpio_desc[gpio].flags);
1667 err = chip->direction_output(chip, gpio - chip->base, 0);
1669 set_bit(FLAG_IS_OUT, &gpio_desc[gpio].flags);
1671 trace_gpio_direction(gpio, value, err);
1673 pr_err("%s: Error in set_value for open drain gpio%d err %d\n",
1674 __func__, gpio, err);
1678 * _gpio_set_open_source() - Set the open source gpio's value.
1679 * @gpio: Gpio whose state need to be set.
1681 * @value: Non-zero for setting it HIGH otherise it will set to LOW.
1683 static void _gpio_set_open_source_value(unsigned gpio,
1684 struct gpio_chip *chip, int value)
1688 err = chip->direction_output(chip, gpio - chip->base, 1);
1690 set_bit(FLAG_IS_OUT, &gpio_desc[gpio].flags);
1692 err = chip->direction_input(chip, gpio - chip->base);
1694 clear_bit(FLAG_IS_OUT, &gpio_desc[gpio].flags);
1696 trace_gpio_direction(gpio, !value, err);
1698 pr_err("%s: Error in set_value for open source gpio%d err %d\n",
1699 __func__, gpio, err);
1704 * __gpio_set_value() - assign a gpio's value
1705 * @gpio: gpio whose value will be assigned
1706 * @value: value to assign
1709 * This is used directly or indirectly to implement gpio_set_value().
1710 * It invokes the associated gpio_chip.set() method.
1712 void __gpio_set_value(unsigned gpio, int value)
1714 struct gpio_chip *chip;
1716 chip = gpio_to_chip(gpio);
1717 /* Should be using gpio_set_value_cansleep() */
1718 WARN_ON(chip->can_sleep);
1719 trace_gpio_value(gpio, 0, value);
1720 if (test_bit(FLAG_OPEN_DRAIN, &gpio_desc[gpio].flags))
1721 _gpio_set_open_drain_value(gpio, chip, value);
1722 else if (test_bit(FLAG_OPEN_SOURCE, &gpio_desc[gpio].flags))
1723 _gpio_set_open_source_value(gpio, chip, value);
1725 chip->set(chip, gpio - chip->base, value);
1727 EXPORT_SYMBOL_GPL(__gpio_set_value);
1730 * __gpio_cansleep() - report whether gpio value access will sleep
1731 * @gpio: gpio in question
1734 * This is used directly or indirectly to implement gpio_cansleep(). It
1735 * returns nonzero if access reading or writing the GPIO value can sleep.
1737 int __gpio_cansleep(unsigned gpio)
1739 struct gpio_chip *chip;
1741 /* only call this on GPIOs that are valid! */
1742 chip = gpio_to_chip(gpio);
1744 return chip->can_sleep;
1746 EXPORT_SYMBOL_GPL(__gpio_cansleep);
1749 * __gpio_to_irq() - return the IRQ corresponding to a GPIO
1750 * @gpio: gpio whose IRQ will be returned (already requested)
1753 * This is used directly or indirectly to implement gpio_to_irq().
1754 * It returns the number of the IRQ signaled by this (input) GPIO,
1755 * or a negative errno.
1757 int __gpio_to_irq(unsigned gpio)
1759 struct gpio_chip *chip;
1761 chip = gpio_to_chip(gpio);
1762 return chip->to_irq ? chip->to_irq(chip, gpio - chip->base) : -ENXIO;
1764 EXPORT_SYMBOL_GPL(__gpio_to_irq);
1768 /* There's no value in making it easy to inline GPIO calls that may sleep.
1769 * Common examples include ones connected to I2C or SPI chips.
1772 int gpio_get_value_cansleep(unsigned gpio)
1774 struct gpio_chip *chip;
1777 might_sleep_if(extra_checks);
1778 chip = gpio_to_chip(gpio);
1779 value = chip->get ? chip->get(chip, gpio - chip->base) : 0;
1780 trace_gpio_value(gpio, 1, value);
1783 EXPORT_SYMBOL_GPL(gpio_get_value_cansleep);
1785 void gpio_set_value_cansleep(unsigned gpio, int value)
1787 struct gpio_chip *chip;
1789 might_sleep_if(extra_checks);
1790 chip = gpio_to_chip(gpio);
1791 trace_gpio_value(gpio, 0, value);
1792 if (test_bit(FLAG_OPEN_DRAIN, &gpio_desc[gpio].flags))
1793 _gpio_set_open_drain_value(gpio, chip, value);
1794 else if (test_bit(FLAG_OPEN_SOURCE, &gpio_desc[gpio].flags))
1795 _gpio_set_open_source_value(gpio, chip, value);
1797 chip->set(chip, gpio - chip->base, value);
1799 EXPORT_SYMBOL_GPL(gpio_set_value_cansleep);
1802 #ifdef CONFIG_DEBUG_FS
1804 static void gpiolib_dbg_show(struct seq_file *s, struct gpio_chip *chip)
1807 unsigned gpio = chip->base;
1808 struct gpio_desc *gdesc = &gpio_desc[gpio];
1811 for (i = 0; i < chip->ngpio; i++, gpio++, gdesc++) {
1812 if (!test_bit(FLAG_REQUESTED, &gdesc->flags))
1815 is_out = test_bit(FLAG_IS_OUT, &gdesc->flags);
1816 seq_printf(s, " gpio-%-3d (%-20.20s) %s %s",
1818 is_out ? "out" : "in ",
1820 ? (chip->get(chip, i) ? "hi" : "lo")
1822 seq_printf(s, "\n");
1826 static void *gpiolib_seq_start(struct seq_file *s, loff_t *pos)
1828 struct gpio_chip *chip = NULL;
1833 /* REVISIT this isn't locked against gpio_chip removal ... */
1835 for (gpio = 0; gpio_is_valid(gpio); gpio++) {
1836 if (gpio_desc[gpio].chip == chip)
1839 chip = gpio_desc[gpio].chip;
1843 if (index++ >= *pos) {
1854 static void *gpiolib_seq_next(struct seq_file *s, void *v, loff_t *pos)
1856 struct gpio_chip *chip = v;
1860 /* skip GPIOs provided by the current chip */
1861 for (gpio = chip->base + chip->ngpio; gpio_is_valid(gpio); gpio++) {
1862 chip = gpio_desc[gpio].chip;
1875 static void gpiolib_seq_stop(struct seq_file *s, void *v)
1879 static int gpiolib_seq_show(struct seq_file *s, void *v)
1881 struct gpio_chip *chip = v;
1884 seq_printf(s, "%sGPIOs %d-%d", (char *)s->private,
1885 chip->base, chip->base + chip->ngpio - 1);
1888 seq_printf(s, ", %s/%s", dev->bus ? dev->bus->name : "no-bus",
1891 seq_printf(s, ", %s", chip->label);
1892 if (chip->can_sleep)
1893 seq_printf(s, ", can sleep");
1894 seq_printf(s, ":\n");
1897 chip->dbg_show(s, chip);
1899 gpiolib_dbg_show(s, chip);
1904 static const struct seq_operations gpiolib_seq_ops = {
1905 .start = gpiolib_seq_start,
1906 .next = gpiolib_seq_next,
1907 .stop = gpiolib_seq_stop,
1908 .show = gpiolib_seq_show,
1911 static int gpiolib_open(struct inode *inode, struct file *file)
1913 return seq_open(file, &gpiolib_seq_ops);
1916 static const struct file_operations gpiolib_operations = {
1917 .owner = THIS_MODULE,
1918 .open = gpiolib_open,
1920 .llseek = seq_lseek,
1921 .release = seq_release,
1924 static int __init gpiolib_debugfs_init(void)
1926 /* /sys/kernel/debug/gpio */
1927 (void) debugfs_create_file("gpio", S_IFREG | S_IRUGO,
1928 NULL, NULL, &gpiolib_operations);
1931 subsys_initcall(gpiolib_debugfs_init);
1933 #endif /* DEBUG_FS */