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");
629 status = gpio_export(gpio, true);
633 set_bit(FLAG_SYSFS, &gpio_desc[gpio].flags);
637 pr_debug("%s: status %d\n", __func__, status);
638 return status ? : len;
641 static ssize_t unexport_store(struct class *class,
642 struct class_attribute *attr,
643 const char *buf, size_t len)
648 status = strict_strtol(buf, 0, &gpio);
654 /* reject bogus commands (gpio_unexport ignores them) */
655 if (!gpio_is_valid(gpio))
658 /* No extra locking here; FLAG_SYSFS just signifies that the
659 * request and export were done by on behalf of userspace, so
660 * they may be undone on its behalf too.
662 if (test_and_clear_bit(FLAG_SYSFS, &gpio_desc[gpio].flags)) {
668 pr_debug("%s: status %d\n", __func__, status);
669 return status ? : len;
672 static struct class_attribute gpio_class_attrs[] = {
673 __ATTR(export, 0200, NULL, export_store),
674 __ATTR(unexport, 0200, NULL, unexport_store),
678 static struct class gpio_class = {
680 .owner = THIS_MODULE,
682 .class_attrs = gpio_class_attrs,
687 * gpio_export - export a GPIO through sysfs
688 * @gpio: gpio to make available, already requested
689 * @direction_may_change: true if userspace may change gpio direction
690 * Context: arch_initcall or later
692 * When drivers want to make a GPIO accessible to userspace after they
693 * have requested it -- perhaps while debugging, or as part of their
694 * public interface -- they may use this routine. If the GPIO can
695 * change direction (some can't) and the caller allows it, userspace
696 * will see "direction" sysfs attribute which may be used to change
697 * the gpio's direction. A "value" attribute will always be provided.
699 * Returns zero on success, else an error.
701 int gpio_export(unsigned gpio, bool direction_may_change)
704 struct gpio_desc *desc;
706 const char *ioname = NULL;
709 /* can't export until sysfs is available ... */
711 pr_debug("%s: called too early!\n", __func__);
715 if (!gpio_is_valid(gpio)) {
716 pr_debug("%s: gpio %d is not valid\n", __func__, gpio);
720 mutex_lock(&sysfs_lock);
722 spin_lock_irqsave(&gpio_lock, flags);
723 desc = &gpio_desc[gpio];
724 if (!test_bit(FLAG_REQUESTED, &desc->flags) ||
725 test_bit(FLAG_EXPORT, &desc->flags)) {
726 spin_unlock_irqrestore(&gpio_lock, flags);
727 pr_debug("%s: gpio %d unavailable (requested=%d, exported=%d)\n",
729 test_bit(FLAG_REQUESTED, &desc->flags),
730 test_bit(FLAG_EXPORT, &desc->flags));
734 if (!desc->chip->direction_input || !desc->chip->direction_output)
735 direction_may_change = false;
736 spin_unlock_irqrestore(&gpio_lock, flags);
738 if (desc->chip->names && desc->chip->names[gpio - desc->chip->base])
739 ioname = desc->chip->names[gpio - desc->chip->base];
741 dev = device_create(&gpio_class, desc->chip->dev, MKDEV(0, 0),
742 desc, ioname ? ioname : "gpio%u", gpio);
744 status = PTR_ERR(dev);
748 status = sysfs_create_group(&dev->kobj, &gpio_attr_group);
750 goto fail_unregister_device;
752 if (direction_may_change) {
753 status = device_create_file(dev, &dev_attr_direction);
755 goto fail_unregister_device;
758 if (gpio_to_irq(gpio) >= 0 && (direction_may_change ||
759 !test_bit(FLAG_IS_OUT, &desc->flags))) {
760 status = device_create_file(dev, &dev_attr_edge);
762 goto fail_unregister_device;
765 set_bit(FLAG_EXPORT, &desc->flags);
766 mutex_unlock(&sysfs_lock);
769 fail_unregister_device:
770 device_unregister(dev);
772 mutex_unlock(&sysfs_lock);
773 pr_debug("%s: gpio%d status %d\n", __func__, gpio, status);
776 EXPORT_SYMBOL_GPL(gpio_export);
778 static int match_export(struct device *dev, void *data)
780 return dev_get_drvdata(dev) == data;
784 * gpio_export_link - create a sysfs link to an exported GPIO node
785 * @dev: device under which to create symlink
786 * @name: name of the symlink
787 * @gpio: gpio to create symlink to, already exported
789 * Set up a symlink from /sys/.../dev/name to /sys/class/gpio/gpioN
790 * node. Caller is responsible for unlinking.
792 * Returns zero on success, else an error.
794 int gpio_export_link(struct device *dev, const char *name, unsigned gpio)
796 struct gpio_desc *desc;
797 int status = -EINVAL;
799 if (!gpio_is_valid(gpio))
802 mutex_lock(&sysfs_lock);
804 desc = &gpio_desc[gpio];
806 if (test_bit(FLAG_EXPORT, &desc->flags)) {
809 tdev = class_find_device(&gpio_class, NULL, desc, match_export);
811 status = sysfs_create_link(&dev->kobj, &tdev->kobj,
818 mutex_unlock(&sysfs_lock);
822 pr_debug("%s: gpio%d status %d\n", __func__, gpio, status);
826 EXPORT_SYMBOL_GPL(gpio_export_link);
830 * gpio_sysfs_set_active_low - set the polarity of gpio sysfs value
831 * @gpio: gpio to change
832 * @value: non-zero to use active low, i.e. inverted values
834 * Set the polarity of /sys/class/gpio/gpioN/value sysfs attribute.
835 * The GPIO does not have to be exported yet. If poll(2) support has
836 * been enabled for either rising or falling edge, it will be
837 * reconfigured to follow the new polarity.
839 * Returns zero on success, else an error.
841 int gpio_sysfs_set_active_low(unsigned gpio, int value)
843 struct gpio_desc *desc;
844 struct device *dev = NULL;
845 int status = -EINVAL;
847 if (!gpio_is_valid(gpio))
850 mutex_lock(&sysfs_lock);
852 desc = &gpio_desc[gpio];
854 if (test_bit(FLAG_EXPORT, &desc->flags)) {
855 dev = class_find_device(&gpio_class, NULL, desc, match_export);
862 status = sysfs_set_active_low(desc, dev, value);
865 mutex_unlock(&sysfs_lock);
869 pr_debug("%s: gpio%d status %d\n", __func__, gpio, status);
873 EXPORT_SYMBOL_GPL(gpio_sysfs_set_active_low);
876 * gpio_unexport - reverse effect of gpio_export()
877 * @gpio: gpio to make unavailable
879 * This is implicit on gpio_free().
881 void gpio_unexport(unsigned gpio)
883 struct gpio_desc *desc;
885 struct device *dev = NULL;
887 if (!gpio_is_valid(gpio)) {
892 mutex_lock(&sysfs_lock);
894 desc = &gpio_desc[gpio];
896 if (test_bit(FLAG_EXPORT, &desc->flags)) {
898 dev = class_find_device(&gpio_class, NULL, desc, match_export);
900 gpio_setup_irq(desc, dev, 0);
901 clear_bit(FLAG_EXPORT, &desc->flags);
906 mutex_unlock(&sysfs_lock);
908 device_unregister(dev);
913 pr_debug("%s: gpio%d status %d\n", __func__, gpio, status);
915 EXPORT_SYMBOL_GPL(gpio_unexport);
917 static int gpiochip_export(struct gpio_chip *chip)
922 /* Many systems register gpio chips for SOC support very early,
923 * before driver model support is available. In those cases we
924 * export this later, in gpiolib_sysfs_init() ... here we just
925 * verify that _some_ field of gpio_class got initialized.
930 /* use chip->base for the ID; it's already known to be unique */
931 mutex_lock(&sysfs_lock);
932 dev = device_create(&gpio_class, chip->dev, MKDEV(0, 0), chip,
933 "gpiochip%d", chip->base);
935 status = sysfs_create_group(&dev->kobj,
936 &gpiochip_attr_group);
938 status = PTR_ERR(dev);
939 chip->exported = (status == 0);
940 mutex_unlock(&sysfs_lock);
946 spin_lock_irqsave(&gpio_lock, flags);
948 while (gpio_desc[gpio].chip == chip)
949 gpio_desc[gpio++].chip = NULL;
950 spin_unlock_irqrestore(&gpio_lock, flags);
952 pr_debug("%s: chip %s status %d\n", __func__,
953 chip->label, status);
959 static void gpiochip_unexport(struct gpio_chip *chip)
964 mutex_lock(&sysfs_lock);
965 dev = class_find_device(&gpio_class, NULL, chip, match_export);
968 device_unregister(dev);
973 mutex_unlock(&sysfs_lock);
976 pr_debug("%s: chip %s status %d\n", __func__,
977 chip->label, status);
980 static int __init gpiolib_sysfs_init(void)
986 status = class_register(&gpio_class);
990 /* Scan and register the gpio_chips which registered very
991 * early (e.g. before the class_register above was called).
993 * We run before arch_initcall() so chip->dev nodes can have
994 * registered, and so arch_initcall() can always gpio_export().
996 spin_lock_irqsave(&gpio_lock, flags);
997 for (gpio = 0; gpio < ARCH_NR_GPIOS; gpio++) {
998 struct gpio_chip *chip;
1000 chip = gpio_desc[gpio].chip;
1001 if (!chip || chip->exported)
1004 spin_unlock_irqrestore(&gpio_lock, flags);
1005 status = gpiochip_export(chip);
1006 spin_lock_irqsave(&gpio_lock, flags);
1008 spin_unlock_irqrestore(&gpio_lock, flags);
1013 postcore_initcall(gpiolib_sysfs_init);
1016 static inline int gpiochip_export(struct gpio_chip *chip)
1021 static inline void gpiochip_unexport(struct gpio_chip *chip)
1025 #endif /* CONFIG_GPIO_SYSFS */
1028 * gpiochip_add() - register a gpio_chip
1029 * @chip: the chip to register, with chip->base initialized
1030 * Context: potentially before irqs or kmalloc will work
1032 * Returns a negative errno if the chip can't be registered, such as
1033 * because the chip->base is invalid or already associated with a
1034 * different chip. Otherwise it returns zero as a success code.
1036 * When gpiochip_add() is called very early during boot, so that GPIOs
1037 * can be freely used, the chip->dev device must be registered before
1038 * the gpio framework's arch_initcall(). Otherwise sysfs initialization
1039 * for GPIOs will fail rudely.
1041 * If chip->base is negative, this requests dynamic assignment of
1042 * a range of valid GPIOs.
1044 int gpiochip_add(struct gpio_chip *chip)
1046 unsigned long flags;
1049 int base = chip->base;
1051 if ((!gpio_is_valid(base) || !gpio_is_valid(base + chip->ngpio - 1))
1057 spin_lock_irqsave(&gpio_lock, flags);
1060 base = gpiochip_find_base(chip->ngpio);
1068 /* these GPIO numbers must not be managed by another gpio_chip */
1069 for (id = base; id < base + chip->ngpio; id++) {
1070 if (gpio_desc[id].chip != NULL) {
1076 for (id = base; id < base + chip->ngpio; id++) {
1077 gpio_desc[id].chip = chip;
1079 /* REVISIT: most hardware initializes GPIOs as
1080 * inputs (often with pullups enabled) so power
1081 * usage is minimized. Linux code should set the
1082 * gpio direction first thing; but until it does,
1083 * we may expose the wrong direction in sysfs.
1085 gpio_desc[id].flags = !chip->direction_input
1086 ? (1 << FLAG_IS_OUT)
1091 of_gpiochip_add(chip);
1094 spin_unlock_irqrestore(&gpio_lock, flags);
1099 status = gpiochip_export(chip);
1103 pr_debug("gpiochip_add: registered GPIOs %d to %d on device: %s\n",
1104 chip->base, chip->base + chip->ngpio - 1,
1105 chip->label ? : "generic");
1109 /* failures here can mean systems won't boot... */
1110 pr_err("gpiochip_add: gpios %d..%d (%s) failed to register\n",
1111 chip->base, chip->base + chip->ngpio - 1,
1112 chip->label ? : "generic");
1115 EXPORT_SYMBOL_GPL(gpiochip_add);
1118 * gpiochip_remove() - unregister a gpio_chip
1119 * @chip: the chip to unregister
1121 * A gpio_chip with any GPIOs still requested may not be removed.
1123 int gpiochip_remove(struct gpio_chip *chip)
1125 unsigned long flags;
1129 spin_lock_irqsave(&gpio_lock, flags);
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 /* These "optional" allocation calls help prevent drivers from stomping
1189 * on each other, and help provide better diagnostics in debugfs.
1190 * They're called even less than the "set direction" calls.
1192 int gpio_request(unsigned gpio, const char *label)
1194 struct gpio_desc *desc;
1195 struct gpio_chip *chip;
1196 int status = -EPROBE_DEFER;
1197 unsigned long flags;
1199 spin_lock_irqsave(&gpio_lock, flags);
1201 if (!gpio_is_valid(gpio))
1203 desc = &gpio_desc[gpio];
1208 if (!try_module_get(chip->owner))
1211 /* NOTE: gpio_request() can be called in early boot,
1212 * before IRQs are enabled, for non-sleeping (SOC) GPIOs.
1215 if (test_and_set_bit(FLAG_REQUESTED, &desc->flags) == 0) {
1216 desc_set_label(desc, label ? : "?");
1220 module_put(chip->owner);
1224 if (chip->request) {
1225 /* chip->request may sleep */
1226 spin_unlock_irqrestore(&gpio_lock, flags);
1227 status = chip->request(chip, gpio - chip->base);
1228 spin_lock_irqsave(&gpio_lock, flags);
1231 desc_set_label(desc, NULL);
1232 module_put(chip->owner);
1233 clear_bit(FLAG_REQUESTED, &desc->flags);
1239 pr_debug("gpio_request: gpio-%d (%s) status %d\n",
1240 gpio, label ? : "?", status);
1241 spin_unlock_irqrestore(&gpio_lock, flags);
1244 EXPORT_SYMBOL_GPL(gpio_request);
1246 void gpio_free(unsigned gpio)
1248 unsigned long flags;
1249 struct gpio_desc *desc;
1250 struct gpio_chip *chip;
1254 if (!gpio_is_valid(gpio)) {
1255 WARN_ON(extra_checks);
1259 gpio_unexport(gpio);
1261 spin_lock_irqsave(&gpio_lock, flags);
1263 desc = &gpio_desc[gpio];
1265 if (chip && test_bit(FLAG_REQUESTED, &desc->flags)) {
1267 spin_unlock_irqrestore(&gpio_lock, flags);
1268 might_sleep_if(chip->can_sleep);
1269 chip->free(chip, gpio - chip->base);
1270 spin_lock_irqsave(&gpio_lock, flags);
1272 desc_set_label(desc, NULL);
1273 module_put(desc->chip->owner);
1274 clear_bit(FLAG_ACTIVE_LOW, &desc->flags);
1275 clear_bit(FLAG_REQUESTED, &desc->flags);
1276 clear_bit(FLAG_OPEN_DRAIN, &desc->flags);
1277 clear_bit(FLAG_OPEN_SOURCE, &desc->flags);
1279 WARN_ON(extra_checks);
1281 spin_unlock_irqrestore(&gpio_lock, flags);
1283 EXPORT_SYMBOL_GPL(gpio_free);
1286 * gpio_request_one - request a single GPIO with initial configuration
1287 * @gpio: the GPIO number
1288 * @flags: GPIO configuration as specified by GPIOF_*
1289 * @label: a literal description string of this GPIO
1291 int gpio_request_one(unsigned gpio, unsigned long flags, const char *label)
1295 err = gpio_request(gpio, label);
1299 if (flags & GPIOF_OPEN_DRAIN)
1300 set_bit(FLAG_OPEN_DRAIN, &gpio_desc[gpio].flags);
1302 if (flags & GPIOF_OPEN_SOURCE)
1303 set_bit(FLAG_OPEN_SOURCE, &gpio_desc[gpio].flags);
1305 if (flags & GPIOF_DIR_IN)
1306 err = gpio_direction_input(gpio);
1308 err = gpio_direction_output(gpio,
1309 (flags & GPIOF_INIT_HIGH) ? 1 : 0);
1314 if (flags & GPIOF_EXPORT) {
1315 err = gpio_export(gpio, flags & GPIOF_EXPORT_CHANGEABLE);
1326 EXPORT_SYMBOL_GPL(gpio_request_one);
1329 * gpio_request_array - request multiple GPIOs in a single call
1330 * @array: array of the 'struct gpio'
1331 * @num: how many GPIOs in the array
1333 int gpio_request_array(const struct gpio *array, size_t num)
1337 for (i = 0; i < num; i++, array++) {
1338 err = gpio_request_one(array->gpio, array->flags, array->label);
1346 gpio_free((--array)->gpio);
1349 EXPORT_SYMBOL_GPL(gpio_request_array);
1352 * gpio_free_array - release multiple GPIOs in a single call
1353 * @array: array of the 'struct gpio'
1354 * @num: how many GPIOs in the array
1356 void gpio_free_array(const struct gpio *array, size_t num)
1359 gpio_free((array++)->gpio);
1361 EXPORT_SYMBOL_GPL(gpio_free_array);
1364 * gpiochip_is_requested - return string iff signal was requested
1365 * @chip: controller managing the signal
1366 * @offset: of signal within controller's 0..(ngpio - 1) range
1368 * Returns NULL if the GPIO is not currently requested, else a string.
1369 * If debugfs support is enabled, the string returned is the label passed
1370 * to gpio_request(); otherwise it is a meaningless constant.
1372 * This function is for use by GPIO controller drivers. The label can
1373 * help with diagnostics, and knowing that the signal is used as a GPIO
1374 * can help avoid accidentally multiplexing it to another controller.
1376 const char *gpiochip_is_requested(struct gpio_chip *chip, unsigned offset)
1378 unsigned gpio = chip->base + offset;
1380 if (!gpio_is_valid(gpio) || gpio_desc[gpio].chip != chip)
1382 if (test_bit(FLAG_REQUESTED, &gpio_desc[gpio].flags) == 0)
1384 #ifdef CONFIG_DEBUG_FS
1385 return gpio_desc[gpio].label;
1390 EXPORT_SYMBOL_GPL(gpiochip_is_requested);
1393 /* Drivers MUST set GPIO direction before making get/set calls. In
1394 * some cases this is done in early boot, before IRQs are enabled.
1396 * As a rule these aren't called more than once (except for drivers
1397 * using the open-drain emulation idiom) so these are natural places
1398 * to accumulate extra debugging checks. Note that we can't (yet)
1399 * rely on gpio_request() having been called beforehand.
1402 int gpio_direction_input(unsigned gpio)
1404 unsigned long flags;
1405 struct gpio_chip *chip;
1406 struct gpio_desc *desc = &gpio_desc[gpio];
1407 int status = -EINVAL;
1409 spin_lock_irqsave(&gpio_lock, flags);
1411 if (!gpio_is_valid(gpio))
1414 if (!chip || !chip->get || !chip->direction_input)
1417 if (gpio >= chip->ngpio)
1419 status = gpio_ensure_requested(desc, gpio);
1423 /* now we know the gpio is valid and chip won't vanish */
1425 spin_unlock_irqrestore(&gpio_lock, flags);
1427 might_sleep_if(chip->can_sleep);
1430 status = chip->request(chip, gpio);
1432 pr_debug("GPIO-%d: chip request fail, %d\n",
1433 chip->base + gpio, status);
1434 /* and it's not available to anyone else ...
1435 * gpio_request() is the fully clean solution.
1441 status = chip->direction_input(chip, gpio);
1443 clear_bit(FLAG_IS_OUT, &desc->flags);
1445 trace_gpio_direction(chip->base + gpio, 1, status);
1449 spin_unlock_irqrestore(&gpio_lock, flags);
1451 pr_debug("%s: gpio-%d status %d\n",
1452 __func__, gpio, status);
1455 EXPORT_SYMBOL_GPL(gpio_direction_input);
1457 int gpio_direction_output(unsigned gpio, int value)
1459 unsigned long flags;
1460 struct gpio_chip *chip;
1461 struct gpio_desc *desc = &gpio_desc[gpio];
1462 int status = -EINVAL;
1464 /* Open drain pin should not be driven to 1 */
1465 if (value && test_bit(FLAG_OPEN_DRAIN, &desc->flags))
1466 return gpio_direction_input(gpio);
1468 /* Open source pin should not be driven to 0 */
1469 if (!value && test_bit(FLAG_OPEN_SOURCE, &desc->flags))
1470 return gpio_direction_input(gpio);
1472 spin_lock_irqsave(&gpio_lock, flags);
1474 if (!gpio_is_valid(gpio))
1477 if (!chip || !chip->set || !chip->direction_output)
1480 if (gpio >= chip->ngpio)
1482 status = gpio_ensure_requested(desc, gpio);
1486 /* now we know the gpio is valid and chip won't vanish */
1488 spin_unlock_irqrestore(&gpio_lock, flags);
1490 might_sleep_if(chip->can_sleep);
1493 status = chip->request(chip, gpio);
1495 pr_debug("GPIO-%d: chip request fail, %d\n",
1496 chip->base + gpio, status);
1497 /* and it's not available to anyone else ...
1498 * gpio_request() is the fully clean solution.
1504 status = chip->direction_output(chip, gpio, value);
1506 set_bit(FLAG_IS_OUT, &desc->flags);
1507 trace_gpio_value(chip->base + gpio, 0, value);
1508 trace_gpio_direction(chip->base + gpio, 0, status);
1512 spin_unlock_irqrestore(&gpio_lock, flags);
1514 pr_debug("%s: gpio-%d status %d\n",
1515 __func__, gpio, status);
1518 EXPORT_SYMBOL_GPL(gpio_direction_output);
1521 * gpio_set_debounce - sets @debounce time for a @gpio
1522 * @gpio: the gpio to set debounce time
1523 * @debounce: debounce time is microseconds
1525 int gpio_set_debounce(unsigned gpio, unsigned debounce)
1527 unsigned long flags;
1528 struct gpio_chip *chip;
1529 struct gpio_desc *desc = &gpio_desc[gpio];
1530 int status = -EINVAL;
1532 spin_lock_irqsave(&gpio_lock, flags);
1534 if (!gpio_is_valid(gpio))
1537 if (!chip || !chip->set || !chip->set_debounce)
1540 if (gpio >= chip->ngpio)
1542 status = gpio_ensure_requested(desc, gpio);
1546 /* now we know the gpio is valid and chip won't vanish */
1548 spin_unlock_irqrestore(&gpio_lock, flags);
1550 might_sleep_if(chip->can_sleep);
1552 return chip->set_debounce(chip, gpio, debounce);
1555 spin_unlock_irqrestore(&gpio_lock, flags);
1557 pr_debug("%s: gpio-%d status %d\n",
1558 __func__, gpio, status);
1562 EXPORT_SYMBOL_GPL(gpio_set_debounce);
1564 /* I/O calls are only valid after configuration completed; the relevant
1565 * "is this a valid GPIO" error checks should already have been done.
1567 * "Get" operations are often inlinable as reading a pin value register,
1568 * and masking the relevant bit in that register.
1570 * When "set" operations are inlinable, they involve writing that mask to
1571 * one register to set a low value, or a different register to set it high.
1572 * Otherwise locking is needed, so there may be little value to inlining.
1574 *------------------------------------------------------------------------
1576 * IMPORTANT!!! The hot paths -- get/set value -- assume that callers
1577 * have requested the GPIO. That can include implicit requesting by
1578 * a direction setting call. Marking a gpio as requested locks its chip
1579 * in memory, guaranteeing that these table lookups need no more locking
1580 * and that gpiochip_remove() will fail.
1582 * REVISIT when debugging, consider adding some instrumentation to ensure
1583 * that the GPIO was actually requested.
1587 * __gpio_get_value() - return a gpio's value
1588 * @gpio: gpio whose value will be returned
1591 * This is used directly or indirectly to implement gpio_get_value().
1592 * It returns the zero or nonzero value provided by the associated
1593 * gpio_chip.get() method; or zero if no such method is provided.
1595 int __gpio_get_value(unsigned gpio)
1597 struct gpio_chip *chip;
1600 chip = gpio_to_chip(gpio);
1601 /* Should be using gpio_get_value_cansleep() */
1602 WARN_ON(chip->can_sleep);
1603 value = chip->get ? chip->get(chip, gpio - chip->base) : 0;
1604 trace_gpio_value(gpio, 1, value);
1607 EXPORT_SYMBOL_GPL(__gpio_get_value);
1610 * _gpio_set_open_drain_value() - Set the open drain gpio's value.
1611 * @gpio: Gpio whose state need to be set.
1613 * @value: Non-zero for setting it HIGH otherise it will set to LOW.
1615 static void _gpio_set_open_drain_value(unsigned gpio,
1616 struct gpio_chip *chip, int value)
1620 err = chip->direction_input(chip, gpio - chip->base);
1622 clear_bit(FLAG_IS_OUT, &gpio_desc[gpio].flags);
1624 err = chip->direction_output(chip, gpio - chip->base, 0);
1626 set_bit(FLAG_IS_OUT, &gpio_desc[gpio].flags);
1628 trace_gpio_direction(gpio, value, err);
1630 pr_err("%s: Error in set_value for open drain gpio%d err %d\n",
1631 __func__, gpio, err);
1635 * _gpio_set_open_source() - Set the open source gpio's value.
1636 * @gpio: Gpio whose state need to be set.
1638 * @value: Non-zero for setting it HIGH otherise it will set to LOW.
1640 static void _gpio_set_open_source_value(unsigned gpio,
1641 struct gpio_chip *chip, int value)
1645 err = chip->direction_output(chip, gpio - chip->base, 1);
1647 set_bit(FLAG_IS_OUT, &gpio_desc[gpio].flags);
1649 err = chip->direction_input(chip, gpio - chip->base);
1651 clear_bit(FLAG_IS_OUT, &gpio_desc[gpio].flags);
1653 trace_gpio_direction(gpio, !value, err);
1655 pr_err("%s: Error in set_value for open source gpio%d err %d\n",
1656 __func__, gpio, err);
1661 * __gpio_set_value() - assign a gpio's value
1662 * @gpio: gpio whose value will be assigned
1663 * @value: value to assign
1666 * This is used directly or indirectly to implement gpio_set_value().
1667 * It invokes the associated gpio_chip.set() method.
1669 void __gpio_set_value(unsigned gpio, int value)
1671 struct gpio_chip *chip;
1673 chip = gpio_to_chip(gpio);
1674 /* Should be using gpio_set_value_cansleep() */
1675 WARN_ON(chip->can_sleep);
1676 trace_gpio_value(gpio, 0, value);
1677 if (test_bit(FLAG_OPEN_DRAIN, &gpio_desc[gpio].flags))
1678 _gpio_set_open_drain_value(gpio, chip, value);
1679 else if (test_bit(FLAG_OPEN_SOURCE, &gpio_desc[gpio].flags))
1680 _gpio_set_open_source_value(gpio, chip, value);
1682 chip->set(chip, gpio - chip->base, value);
1684 EXPORT_SYMBOL_GPL(__gpio_set_value);
1687 * __gpio_cansleep() - report whether gpio value access will sleep
1688 * @gpio: gpio in question
1691 * This is used directly or indirectly to implement gpio_cansleep(). It
1692 * returns nonzero if access reading or writing the GPIO value can sleep.
1694 int __gpio_cansleep(unsigned gpio)
1696 struct gpio_chip *chip;
1698 /* only call this on GPIOs that are valid! */
1699 chip = gpio_to_chip(gpio);
1701 return chip->can_sleep;
1703 EXPORT_SYMBOL_GPL(__gpio_cansleep);
1706 * __gpio_to_irq() - return the IRQ corresponding to a GPIO
1707 * @gpio: gpio whose IRQ will be returned (already requested)
1710 * This is used directly or indirectly to implement gpio_to_irq().
1711 * It returns the number of the IRQ signaled by this (input) GPIO,
1712 * or a negative errno.
1714 int __gpio_to_irq(unsigned gpio)
1716 struct gpio_chip *chip;
1718 chip = gpio_to_chip(gpio);
1719 return chip->to_irq ? chip->to_irq(chip, gpio - chip->base) : -ENXIO;
1721 EXPORT_SYMBOL_GPL(__gpio_to_irq);
1725 /* There's no value in making it easy to inline GPIO calls that may sleep.
1726 * Common examples include ones connected to I2C or SPI chips.
1729 int gpio_get_value_cansleep(unsigned gpio)
1731 struct gpio_chip *chip;
1734 might_sleep_if(extra_checks);
1735 chip = gpio_to_chip(gpio);
1736 value = chip->get ? chip->get(chip, gpio - chip->base) : 0;
1737 trace_gpio_value(gpio, 1, value);
1740 EXPORT_SYMBOL_GPL(gpio_get_value_cansleep);
1742 void gpio_set_value_cansleep(unsigned gpio, int value)
1744 struct gpio_chip *chip;
1746 might_sleep_if(extra_checks);
1747 chip = gpio_to_chip(gpio);
1748 trace_gpio_value(gpio, 0, value);
1749 if (test_bit(FLAG_OPEN_DRAIN, &gpio_desc[gpio].flags))
1750 _gpio_set_open_drain_value(gpio, chip, value);
1751 else if (test_bit(FLAG_OPEN_SOURCE, &gpio_desc[gpio].flags))
1752 _gpio_set_open_source_value(gpio, chip, value);
1754 chip->set(chip, gpio - chip->base, value);
1756 EXPORT_SYMBOL_GPL(gpio_set_value_cansleep);
1759 #ifdef CONFIG_DEBUG_FS
1761 static void gpiolib_dbg_show(struct seq_file *s, struct gpio_chip *chip)
1764 unsigned gpio = chip->base;
1765 struct gpio_desc *gdesc = &gpio_desc[gpio];
1768 for (i = 0; i < chip->ngpio; i++, gpio++, gdesc++) {
1769 if (!test_bit(FLAG_REQUESTED, &gdesc->flags))
1772 is_out = test_bit(FLAG_IS_OUT, &gdesc->flags);
1773 seq_printf(s, " gpio-%-3d (%-20.20s) %s %s",
1775 is_out ? "out" : "in ",
1777 ? (chip->get(chip, i) ? "hi" : "lo")
1779 seq_printf(s, "\n");
1783 static void *gpiolib_seq_start(struct seq_file *s, loff_t *pos)
1785 struct gpio_chip *chip = NULL;
1790 /* REVISIT this isn't locked against gpio_chip removal ... */
1792 for (gpio = 0; gpio_is_valid(gpio); gpio++) {
1793 if (gpio_desc[gpio].chip == chip)
1796 chip = gpio_desc[gpio].chip;
1800 if (index++ >= *pos) {
1811 static void *gpiolib_seq_next(struct seq_file *s, void *v, loff_t *pos)
1813 struct gpio_chip *chip = v;
1817 /* skip GPIOs provided by the current chip */
1818 for (gpio = chip->base + chip->ngpio; gpio_is_valid(gpio); gpio++) {
1819 chip = gpio_desc[gpio].chip;
1832 static void gpiolib_seq_stop(struct seq_file *s, void *v)
1836 static int gpiolib_seq_show(struct seq_file *s, void *v)
1838 struct gpio_chip *chip = v;
1841 seq_printf(s, "%sGPIOs %d-%d", (char *)s->private,
1842 chip->base, chip->base + chip->ngpio - 1);
1845 seq_printf(s, ", %s/%s", dev->bus ? dev->bus->name : "no-bus",
1848 seq_printf(s, ", %s", chip->label);
1849 if (chip->can_sleep)
1850 seq_printf(s, ", can sleep");
1851 seq_printf(s, ":\n");
1854 chip->dbg_show(s, chip);
1856 gpiolib_dbg_show(s, chip);
1861 static const struct seq_operations gpiolib_seq_ops = {
1862 .start = gpiolib_seq_start,
1863 .next = gpiolib_seq_next,
1864 .stop = gpiolib_seq_stop,
1865 .show = gpiolib_seq_show,
1868 static int gpiolib_open(struct inode *inode, struct file *file)
1870 return seq_open(file, &gpiolib_seq_ops);
1873 static const struct file_operations gpiolib_operations = {
1874 .owner = THIS_MODULE,
1875 .open = gpiolib_open,
1877 .llseek = seq_lseek,
1878 .release = seq_release,
1881 static int __init gpiolib_debugfs_init(void)
1883 /* /sys/kernel/debug/gpio */
1884 (void) debugfs_create_file("gpio", S_IFREG | S_IRUGO,
1885 NULL, NULL, &gpiolib_operations);
1888 subsys_initcall(gpiolib_debugfs_init);
1890 #endif /* DEBUG_FS */