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 /* caller ensures gpio is valid and requested, chip->get_direction may sleep */
195 static int gpio_get_direction(unsigned gpio)
197 struct gpio_chip *chip;
198 struct gpio_desc *desc = &gpio_desc[gpio];
199 int status = -EINVAL;
201 chip = gpio_to_chip(gpio);
204 if (!chip->get_direction)
207 status = chip->get_direction(chip, gpio);
209 /* GPIOF_DIR_IN, or other positive */
211 clear_bit(FLAG_IS_OUT, &desc->flags);
215 set_bit(FLAG_IS_OUT, &desc->flags);
220 #ifdef CONFIG_GPIO_SYSFS
222 /* lock protects against unexport_gpio() being called while
223 * sysfs files are active.
225 static DEFINE_MUTEX(sysfs_lock);
228 * /sys/class/gpio/gpioN... only for GPIOs that are exported
230 * * MAY BE OMITTED if kernel won't allow direction changes
231 * * is read/write as "in" or "out"
232 * * may also be written as "high" or "low", initializing
233 * output value as specified ("out" implies "low")
235 * * always readable, subject to hardware behavior
236 * * may be writable, as zero/nonzero
238 * * configures behavior of poll(2) on /value
239 * * available only if pin can generate IRQs on input
240 * * is read/write as "none", "falling", "rising", or "both"
242 * * configures polarity of /value
243 * * is read/write as zero/nonzero
244 * * also affects existing and subsequent "falling" and "rising"
245 * /edge configuration
248 static ssize_t gpio_direction_show(struct device *dev,
249 struct device_attribute *attr, char *buf)
251 const struct gpio_desc *desc = dev_get_drvdata(dev);
252 unsigned gpio = desc - gpio_desc;
255 mutex_lock(&sysfs_lock);
257 if (!test_bit(FLAG_EXPORT, &desc->flags))
260 gpio_get_direction(gpio);
261 status = sprintf(buf, "%s\n",
262 test_bit(FLAG_IS_OUT, &desc->flags)
265 mutex_unlock(&sysfs_lock);
269 static ssize_t gpio_direction_store(struct device *dev,
270 struct device_attribute *attr, const char *buf, size_t size)
272 const struct gpio_desc *desc = dev_get_drvdata(dev);
273 unsigned gpio = desc - gpio_desc;
276 mutex_lock(&sysfs_lock);
278 if (!test_bit(FLAG_EXPORT, &desc->flags))
280 else if (sysfs_streq(buf, "high"))
281 status = gpio_direction_output(gpio, 1);
282 else if (sysfs_streq(buf, "out") || sysfs_streq(buf, "low"))
283 status = gpio_direction_output(gpio, 0);
284 else if (sysfs_streq(buf, "in"))
285 status = gpio_direction_input(gpio);
289 mutex_unlock(&sysfs_lock);
290 return status ? : size;
293 static /* const */ DEVICE_ATTR(direction, 0644,
294 gpio_direction_show, gpio_direction_store);
296 static ssize_t gpio_value_show(struct device *dev,
297 struct device_attribute *attr, char *buf)
299 const struct gpio_desc *desc = dev_get_drvdata(dev);
300 unsigned gpio = desc - gpio_desc;
303 mutex_lock(&sysfs_lock);
305 if (!test_bit(FLAG_EXPORT, &desc->flags)) {
310 value = !!gpio_get_value_cansleep(gpio);
311 if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
314 status = sprintf(buf, "%d\n", value);
317 mutex_unlock(&sysfs_lock);
321 static ssize_t gpio_value_store(struct device *dev,
322 struct device_attribute *attr, const char *buf, size_t size)
324 const struct gpio_desc *desc = dev_get_drvdata(dev);
325 unsigned gpio = desc - gpio_desc;
328 mutex_lock(&sysfs_lock);
330 if (!test_bit(FLAG_EXPORT, &desc->flags))
332 else if (!test_bit(FLAG_IS_OUT, &desc->flags))
337 status = strict_strtol(buf, 0, &value);
339 if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
341 gpio_set_value_cansleep(gpio, value != 0);
346 mutex_unlock(&sysfs_lock);
350 static const DEVICE_ATTR(value, 0644,
351 gpio_value_show, gpio_value_store);
353 static irqreturn_t gpio_sysfs_irq(int irq, void *priv)
355 struct sysfs_dirent *value_sd = priv;
357 sysfs_notify_dirent(value_sd);
361 static int gpio_setup_irq(struct gpio_desc *desc, struct device *dev,
362 unsigned long gpio_flags)
364 struct sysfs_dirent *value_sd;
365 unsigned long irq_flags;
368 if ((desc->flags & GPIO_TRIGGER_MASK) == gpio_flags)
371 irq = gpio_to_irq(desc - gpio_desc);
375 id = desc->flags >> ID_SHIFT;
376 value_sd = idr_find(&dirent_idr, id);
378 free_irq(irq, value_sd);
380 desc->flags &= ~GPIO_TRIGGER_MASK;
387 irq_flags = IRQF_SHARED;
388 if (test_bit(FLAG_TRIG_FALL, &gpio_flags))
389 irq_flags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ?
390 IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING;
391 if (test_bit(FLAG_TRIG_RISE, &gpio_flags))
392 irq_flags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ?
393 IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING;
396 value_sd = sysfs_get_dirent(dev->kobj.sd, NULL, "value");
404 if (idr_pre_get(&dirent_idr, GFP_KERNEL))
405 ret = idr_get_new_above(&dirent_idr, value_sd,
407 } while (ret == -EAGAIN);
412 desc->flags &= GPIO_FLAGS_MASK;
413 desc->flags |= (unsigned long)id << ID_SHIFT;
415 if (desc->flags >> ID_SHIFT != id) {
421 ret = request_any_context_irq(irq, gpio_sysfs_irq, irq_flags,
422 "gpiolib", value_sd);
426 desc->flags |= gpio_flags;
430 idr_remove(&dirent_idr, id);
431 desc->flags &= GPIO_FLAGS_MASK;
439 static const struct {
442 } trigger_types[] = {
444 { "falling", BIT(FLAG_TRIG_FALL) },
445 { "rising", BIT(FLAG_TRIG_RISE) },
446 { "both", BIT(FLAG_TRIG_FALL) | BIT(FLAG_TRIG_RISE) },
449 static ssize_t gpio_edge_show(struct device *dev,
450 struct device_attribute *attr, char *buf)
452 const struct gpio_desc *desc = dev_get_drvdata(dev);
455 mutex_lock(&sysfs_lock);
457 if (!test_bit(FLAG_EXPORT, &desc->flags))
463 for (i = 0; i < ARRAY_SIZE(trigger_types); i++)
464 if ((desc->flags & GPIO_TRIGGER_MASK)
465 == trigger_types[i].flags) {
466 status = sprintf(buf, "%s\n",
467 trigger_types[i].name);
472 mutex_unlock(&sysfs_lock);
476 static ssize_t gpio_edge_store(struct device *dev,
477 struct device_attribute *attr, const char *buf, size_t size)
479 struct gpio_desc *desc = dev_get_drvdata(dev);
483 for (i = 0; i < ARRAY_SIZE(trigger_types); i++)
484 if (sysfs_streq(trigger_types[i].name, buf))
489 mutex_lock(&sysfs_lock);
491 if (!test_bit(FLAG_EXPORT, &desc->flags))
494 status = gpio_setup_irq(desc, dev, trigger_types[i].flags);
499 mutex_unlock(&sysfs_lock);
504 static DEVICE_ATTR(edge, 0644, gpio_edge_show, gpio_edge_store);
506 static int sysfs_set_active_low(struct gpio_desc *desc, struct device *dev,
511 if (!!test_bit(FLAG_ACTIVE_LOW, &desc->flags) == !!value)
515 set_bit(FLAG_ACTIVE_LOW, &desc->flags);
517 clear_bit(FLAG_ACTIVE_LOW, &desc->flags);
519 /* reconfigure poll(2) support if enabled on one edge only */
520 if (dev != NULL && (!!test_bit(FLAG_TRIG_RISE, &desc->flags) ^
521 !!test_bit(FLAG_TRIG_FALL, &desc->flags))) {
522 unsigned long trigger_flags = desc->flags & GPIO_TRIGGER_MASK;
524 gpio_setup_irq(desc, dev, 0);
525 status = gpio_setup_irq(desc, dev, trigger_flags);
531 static ssize_t gpio_active_low_show(struct device *dev,
532 struct device_attribute *attr, char *buf)
534 const struct gpio_desc *desc = dev_get_drvdata(dev);
537 mutex_lock(&sysfs_lock);
539 if (!test_bit(FLAG_EXPORT, &desc->flags))
542 status = sprintf(buf, "%d\n",
543 !!test_bit(FLAG_ACTIVE_LOW, &desc->flags));
545 mutex_unlock(&sysfs_lock);
550 static ssize_t gpio_active_low_store(struct device *dev,
551 struct device_attribute *attr, const char *buf, size_t size)
553 struct gpio_desc *desc = dev_get_drvdata(dev);
556 mutex_lock(&sysfs_lock);
558 if (!test_bit(FLAG_EXPORT, &desc->flags)) {
563 status = strict_strtol(buf, 0, &value);
565 status = sysfs_set_active_low(desc, dev, value != 0);
568 mutex_unlock(&sysfs_lock);
570 return status ? : size;
573 static const DEVICE_ATTR(active_low, 0644,
574 gpio_active_low_show, gpio_active_low_store);
576 static const struct attribute *gpio_attrs[] = {
577 &dev_attr_value.attr,
578 &dev_attr_active_low.attr,
582 static const struct attribute_group gpio_attr_group = {
583 .attrs = (struct attribute **) gpio_attrs,
587 * /sys/class/gpio/gpiochipN/
588 * /base ... matching gpio_chip.base (N)
589 * /label ... matching gpio_chip.label
590 * /ngpio ... matching gpio_chip.ngpio
593 static ssize_t chip_base_show(struct device *dev,
594 struct device_attribute *attr, char *buf)
596 const struct gpio_chip *chip = dev_get_drvdata(dev);
598 return sprintf(buf, "%d\n", chip->base);
600 static DEVICE_ATTR(base, 0444, chip_base_show, NULL);
602 static ssize_t chip_label_show(struct device *dev,
603 struct device_attribute *attr, char *buf)
605 const struct gpio_chip *chip = dev_get_drvdata(dev);
607 return sprintf(buf, "%s\n", chip->label ? : "");
609 static DEVICE_ATTR(label, 0444, chip_label_show, NULL);
611 static ssize_t chip_ngpio_show(struct device *dev,
612 struct device_attribute *attr, char *buf)
614 const struct gpio_chip *chip = dev_get_drvdata(dev);
616 return sprintf(buf, "%u\n", chip->ngpio);
618 static DEVICE_ATTR(ngpio, 0444, chip_ngpio_show, NULL);
620 static const struct attribute *gpiochip_attrs[] = {
622 &dev_attr_label.attr,
623 &dev_attr_ngpio.attr,
627 static const struct attribute_group gpiochip_attr_group = {
628 .attrs = (struct attribute **) gpiochip_attrs,
632 * /sys/class/gpio/export ... write-only
633 * integer N ... number of GPIO to export (full access)
634 * /sys/class/gpio/unexport ... write-only
635 * integer N ... number of GPIO to unexport
637 static ssize_t export_store(struct class *class,
638 struct class_attribute *attr,
639 const char *buf, size_t len)
644 status = strict_strtol(buf, 0, &gpio);
648 /* No extra locking here; FLAG_SYSFS just signifies that the
649 * request and export were done by on behalf of userspace, so
650 * they may be undone on its behalf too.
653 status = gpio_request(gpio, "sysfs");
657 status = gpio_export(gpio, true);
661 set_bit(FLAG_SYSFS, &gpio_desc[gpio].flags);
665 pr_debug("%s: status %d\n", __func__, status);
666 return status ? : len;
669 static ssize_t unexport_store(struct class *class,
670 struct class_attribute *attr,
671 const char *buf, size_t len)
676 status = strict_strtol(buf, 0, &gpio);
682 /* reject bogus commands (gpio_unexport ignores them) */
683 if (!gpio_is_valid(gpio))
686 /* No extra locking here; FLAG_SYSFS just signifies that the
687 * request and export were done by on behalf of userspace, so
688 * they may be undone on its behalf too.
690 if (test_and_clear_bit(FLAG_SYSFS, &gpio_desc[gpio].flags)) {
696 pr_debug("%s: status %d\n", __func__, status);
697 return status ? : len;
700 static struct class_attribute gpio_class_attrs[] = {
701 __ATTR(export, 0200, NULL, export_store),
702 __ATTR(unexport, 0200, NULL, unexport_store),
706 static struct class gpio_class = {
708 .owner = THIS_MODULE,
710 .class_attrs = gpio_class_attrs,
715 * gpio_export - export a GPIO through sysfs
716 * @gpio: gpio to make available, already requested
717 * @direction_may_change: true if userspace may change gpio direction
718 * Context: arch_initcall or later
720 * When drivers want to make a GPIO accessible to userspace after they
721 * have requested it -- perhaps while debugging, or as part of their
722 * public interface -- they may use this routine. If the GPIO can
723 * change direction (some can't) and the caller allows it, userspace
724 * will see "direction" sysfs attribute which may be used to change
725 * the gpio's direction. A "value" attribute will always be provided.
727 * Returns zero on success, else an error.
729 int gpio_export(unsigned gpio, bool direction_may_change)
732 struct gpio_desc *desc;
734 const char *ioname = NULL;
737 /* can't export until sysfs is available ... */
739 pr_debug("%s: called too early!\n", __func__);
743 if (!gpio_is_valid(gpio)) {
744 pr_debug("%s: gpio %d is not valid\n", __func__, gpio);
748 mutex_lock(&sysfs_lock);
750 spin_lock_irqsave(&gpio_lock, flags);
751 desc = &gpio_desc[gpio];
752 if (!test_bit(FLAG_REQUESTED, &desc->flags) ||
753 test_bit(FLAG_EXPORT, &desc->flags)) {
754 spin_unlock_irqrestore(&gpio_lock, flags);
755 pr_debug("%s: gpio %d unavailable (requested=%d, exported=%d)\n",
757 test_bit(FLAG_REQUESTED, &desc->flags),
758 test_bit(FLAG_EXPORT, &desc->flags));
762 if (!desc->chip->direction_input || !desc->chip->direction_output)
763 direction_may_change = false;
764 spin_unlock_irqrestore(&gpio_lock, flags);
766 if (desc->chip->names && desc->chip->names[gpio - desc->chip->base])
767 ioname = desc->chip->names[gpio - desc->chip->base];
769 dev = device_create(&gpio_class, desc->chip->dev, MKDEV(0, 0),
770 desc, ioname ? ioname : "gpio%u", gpio);
772 status = PTR_ERR(dev);
776 status = sysfs_create_group(&dev->kobj, &gpio_attr_group);
778 goto fail_unregister_device;
780 if (direction_may_change) {
781 status = device_create_file(dev, &dev_attr_direction);
783 goto fail_unregister_device;
786 if (gpio_to_irq(gpio) >= 0 && (direction_may_change ||
787 !test_bit(FLAG_IS_OUT, &desc->flags))) {
788 status = device_create_file(dev, &dev_attr_edge);
790 goto fail_unregister_device;
793 set_bit(FLAG_EXPORT, &desc->flags);
794 mutex_unlock(&sysfs_lock);
797 fail_unregister_device:
798 device_unregister(dev);
800 mutex_unlock(&sysfs_lock);
801 pr_debug("%s: gpio%d status %d\n", __func__, gpio, status);
804 EXPORT_SYMBOL_GPL(gpio_export);
806 static int match_export(struct device *dev, void *data)
808 return dev_get_drvdata(dev) == data;
812 * gpio_export_link - create a sysfs link to an exported GPIO node
813 * @dev: device under which to create symlink
814 * @name: name of the symlink
815 * @gpio: gpio to create symlink to, already exported
817 * Set up a symlink from /sys/.../dev/name to /sys/class/gpio/gpioN
818 * node. Caller is responsible for unlinking.
820 * Returns zero on success, else an error.
822 int gpio_export_link(struct device *dev, const char *name, unsigned gpio)
824 struct gpio_desc *desc;
825 int status = -EINVAL;
827 if (!gpio_is_valid(gpio))
830 mutex_lock(&sysfs_lock);
832 desc = &gpio_desc[gpio];
834 if (test_bit(FLAG_EXPORT, &desc->flags)) {
837 tdev = class_find_device(&gpio_class, NULL, desc, match_export);
839 status = sysfs_create_link(&dev->kobj, &tdev->kobj,
846 mutex_unlock(&sysfs_lock);
850 pr_debug("%s: gpio%d status %d\n", __func__, gpio, status);
854 EXPORT_SYMBOL_GPL(gpio_export_link);
858 * gpio_sysfs_set_active_low - set the polarity of gpio sysfs value
859 * @gpio: gpio to change
860 * @value: non-zero to use active low, i.e. inverted values
862 * Set the polarity of /sys/class/gpio/gpioN/value sysfs attribute.
863 * The GPIO does not have to be exported yet. If poll(2) support has
864 * been enabled for either rising or falling edge, it will be
865 * reconfigured to follow the new polarity.
867 * Returns zero on success, else an error.
869 int gpio_sysfs_set_active_low(unsigned gpio, int value)
871 struct gpio_desc *desc;
872 struct device *dev = NULL;
873 int status = -EINVAL;
875 if (!gpio_is_valid(gpio))
878 mutex_lock(&sysfs_lock);
880 desc = &gpio_desc[gpio];
882 if (test_bit(FLAG_EXPORT, &desc->flags)) {
883 dev = class_find_device(&gpio_class, NULL, desc, match_export);
890 status = sysfs_set_active_low(desc, dev, value);
893 mutex_unlock(&sysfs_lock);
897 pr_debug("%s: gpio%d status %d\n", __func__, gpio, status);
901 EXPORT_SYMBOL_GPL(gpio_sysfs_set_active_low);
904 * gpio_unexport - reverse effect of gpio_export()
905 * @gpio: gpio to make unavailable
907 * This is implicit on gpio_free().
909 void gpio_unexport(unsigned gpio)
911 struct gpio_desc *desc;
913 struct device *dev = NULL;
915 if (!gpio_is_valid(gpio)) {
920 mutex_lock(&sysfs_lock);
922 desc = &gpio_desc[gpio];
924 if (test_bit(FLAG_EXPORT, &desc->flags)) {
926 dev = class_find_device(&gpio_class, NULL, desc, match_export);
928 gpio_setup_irq(desc, dev, 0);
929 clear_bit(FLAG_EXPORT, &desc->flags);
934 mutex_unlock(&sysfs_lock);
936 device_unregister(dev);
941 pr_debug("%s: gpio%d status %d\n", __func__, gpio, status);
943 EXPORT_SYMBOL_GPL(gpio_unexport);
945 static int gpiochip_export(struct gpio_chip *chip)
950 /* Many systems register gpio chips for SOC support very early,
951 * before driver model support is available. In those cases we
952 * export this later, in gpiolib_sysfs_init() ... here we just
953 * verify that _some_ field of gpio_class got initialized.
958 /* use chip->base for the ID; it's already known to be unique */
959 mutex_lock(&sysfs_lock);
960 dev = device_create(&gpio_class, chip->dev, MKDEV(0, 0), chip,
961 "gpiochip%d", chip->base);
963 status = sysfs_create_group(&dev->kobj,
964 &gpiochip_attr_group);
966 status = PTR_ERR(dev);
967 chip->exported = (status == 0);
968 mutex_unlock(&sysfs_lock);
974 spin_lock_irqsave(&gpio_lock, flags);
976 while (gpio_desc[gpio].chip == chip)
977 gpio_desc[gpio++].chip = NULL;
978 spin_unlock_irqrestore(&gpio_lock, flags);
980 pr_debug("%s: chip %s status %d\n", __func__,
981 chip->label, status);
987 static void gpiochip_unexport(struct gpio_chip *chip)
992 mutex_lock(&sysfs_lock);
993 dev = class_find_device(&gpio_class, NULL, chip, match_export);
996 device_unregister(dev);
1001 mutex_unlock(&sysfs_lock);
1004 pr_debug("%s: chip %s status %d\n", __func__,
1005 chip->label, status);
1008 static int __init gpiolib_sysfs_init(void)
1011 unsigned long flags;
1014 status = class_register(&gpio_class);
1018 /* Scan and register the gpio_chips which registered very
1019 * early (e.g. before the class_register above was called).
1021 * We run before arch_initcall() so chip->dev nodes can have
1022 * registered, and so arch_initcall() can always gpio_export().
1024 spin_lock_irqsave(&gpio_lock, flags);
1025 for (gpio = 0; gpio < ARCH_NR_GPIOS; gpio++) {
1026 struct gpio_chip *chip;
1028 chip = gpio_desc[gpio].chip;
1029 if (!chip || chip->exported)
1032 spin_unlock_irqrestore(&gpio_lock, flags);
1033 status = gpiochip_export(chip);
1034 spin_lock_irqsave(&gpio_lock, flags);
1036 spin_unlock_irqrestore(&gpio_lock, flags);
1041 postcore_initcall(gpiolib_sysfs_init);
1044 static inline int gpiochip_export(struct gpio_chip *chip)
1049 static inline void gpiochip_unexport(struct gpio_chip *chip)
1053 #endif /* CONFIG_GPIO_SYSFS */
1056 * gpiochip_add() - register a gpio_chip
1057 * @chip: the chip to register, with chip->base initialized
1058 * Context: potentially before irqs or kmalloc will work
1060 * Returns a negative errno if the chip can't be registered, such as
1061 * because the chip->base is invalid or already associated with a
1062 * different chip. Otherwise it returns zero as a success code.
1064 * When gpiochip_add() is called very early during boot, so that GPIOs
1065 * can be freely used, the chip->dev device must be registered before
1066 * the gpio framework's arch_initcall(). Otherwise sysfs initialization
1067 * for GPIOs will fail rudely.
1069 * If chip->base is negative, this requests dynamic assignment of
1070 * a range of valid GPIOs.
1072 int gpiochip_add(struct gpio_chip *chip)
1074 unsigned long flags;
1077 int base = chip->base;
1079 if ((!gpio_is_valid(base) || !gpio_is_valid(base + chip->ngpio - 1))
1085 spin_lock_irqsave(&gpio_lock, flags);
1088 base = gpiochip_find_base(chip->ngpio);
1096 /* these GPIO numbers must not be managed by another gpio_chip */
1097 for (id = base; id < base + chip->ngpio; id++) {
1098 if (gpio_desc[id].chip != NULL) {
1104 for (id = base; id < base + chip->ngpio; id++) {
1105 gpio_desc[id].chip = chip;
1107 /* REVISIT: most hardware initializes GPIOs as
1108 * inputs (often with pullups enabled) so power
1109 * usage is minimized. Linux code should set the
1110 * gpio direction first thing; but until it does,
1111 * and in case chip->get_direction is not set,
1112 * we may expose the wrong direction in sysfs.
1114 gpio_desc[id].flags = !chip->direction_input
1115 ? (1 << FLAG_IS_OUT)
1120 of_gpiochip_add(chip);
1123 spin_unlock_irqrestore(&gpio_lock, flags);
1128 status = gpiochip_export(chip);
1132 pr_debug("gpiochip_add: registered GPIOs %d to %d on device: %s\n",
1133 chip->base, chip->base + chip->ngpio - 1,
1134 chip->label ? : "generic");
1138 /* failures here can mean systems won't boot... */
1139 pr_err("gpiochip_add: gpios %d..%d (%s) failed to register\n",
1140 chip->base, chip->base + chip->ngpio - 1,
1141 chip->label ? : "generic");
1144 EXPORT_SYMBOL_GPL(gpiochip_add);
1147 * gpiochip_remove() - unregister a gpio_chip
1148 * @chip: the chip to unregister
1150 * A gpio_chip with any GPIOs still requested may not be removed.
1152 int gpiochip_remove(struct gpio_chip *chip)
1154 unsigned long flags;
1158 spin_lock_irqsave(&gpio_lock, flags);
1160 of_gpiochip_remove(chip);
1162 for (id = chip->base; id < chip->base + chip->ngpio; id++) {
1163 if (test_bit(FLAG_REQUESTED, &gpio_desc[id].flags)) {
1169 for (id = chip->base; id < chip->base + chip->ngpio; id++)
1170 gpio_desc[id].chip = NULL;
1173 spin_unlock_irqrestore(&gpio_lock, flags);
1176 gpiochip_unexport(chip);
1180 EXPORT_SYMBOL_GPL(gpiochip_remove);
1183 * gpiochip_find() - iterator for locating a specific gpio_chip
1184 * @data: data to pass to match function
1185 * @callback: Callback function to check gpio_chip
1187 * Similar to bus_find_device. It returns a reference to a gpio_chip as
1188 * determined by a user supplied @match callback. The callback should return
1189 * 0 if the device doesn't match and non-zero if it does. If the callback is
1190 * non-zero, this function will return to the caller and not iterate over any
1193 struct gpio_chip *gpiochip_find(void *data,
1194 int (*match)(struct gpio_chip *chip,
1197 struct gpio_chip *chip = NULL;
1198 unsigned long flags;
1201 spin_lock_irqsave(&gpio_lock, flags);
1202 for (i = 0; i < ARCH_NR_GPIOS; i++) {
1203 if (!gpio_desc[i].chip)
1206 if (match(gpio_desc[i].chip, data)) {
1207 chip = gpio_desc[i].chip;
1211 spin_unlock_irqrestore(&gpio_lock, flags);
1215 EXPORT_SYMBOL_GPL(gpiochip_find);
1217 /* These "optional" allocation calls help prevent drivers from stomping
1218 * on each other, and help provide better diagnostics in debugfs.
1219 * They're called even less than the "set direction" calls.
1221 int gpio_request(unsigned gpio, const char *label)
1223 struct gpio_desc *desc;
1224 struct gpio_chip *chip;
1225 int status = -EPROBE_DEFER;
1226 unsigned long flags;
1228 spin_lock_irqsave(&gpio_lock, flags);
1230 if (!gpio_is_valid(gpio))
1232 desc = &gpio_desc[gpio];
1237 if (!try_module_get(chip->owner))
1240 /* NOTE: gpio_request() can be called in early boot,
1241 * before IRQs are enabled, for non-sleeping (SOC) GPIOs.
1244 if (test_and_set_bit(FLAG_REQUESTED, &desc->flags) == 0) {
1245 desc_set_label(desc, label ? : "?");
1249 module_put(chip->owner);
1253 if (chip->request) {
1254 /* chip->request may sleep */
1255 spin_unlock_irqrestore(&gpio_lock, flags);
1256 status = chip->request(chip, gpio - chip->base);
1257 spin_lock_irqsave(&gpio_lock, flags);
1260 desc_set_label(desc, NULL);
1261 module_put(chip->owner);
1262 clear_bit(FLAG_REQUESTED, &desc->flags);
1266 if (chip->get_direction) {
1267 /* chip->get_direction may sleep */
1268 spin_unlock_irqrestore(&gpio_lock, flags);
1269 gpio_get_direction(gpio);
1270 spin_lock_irqsave(&gpio_lock, flags);
1274 pr_debug("gpio_request: gpio-%d (%s) status %d\n",
1275 gpio, label ? : "?", status);
1276 spin_unlock_irqrestore(&gpio_lock, flags);
1279 EXPORT_SYMBOL_GPL(gpio_request);
1281 void gpio_free(unsigned gpio)
1283 unsigned long flags;
1284 struct gpio_desc *desc;
1285 struct gpio_chip *chip;
1289 if (!gpio_is_valid(gpio)) {
1290 WARN_ON(extra_checks);
1294 gpio_unexport(gpio);
1296 spin_lock_irqsave(&gpio_lock, flags);
1298 desc = &gpio_desc[gpio];
1300 if (chip && test_bit(FLAG_REQUESTED, &desc->flags)) {
1302 spin_unlock_irqrestore(&gpio_lock, flags);
1303 might_sleep_if(chip->can_sleep);
1304 chip->free(chip, gpio - chip->base);
1305 spin_lock_irqsave(&gpio_lock, flags);
1307 desc_set_label(desc, NULL);
1308 module_put(desc->chip->owner);
1309 clear_bit(FLAG_ACTIVE_LOW, &desc->flags);
1310 clear_bit(FLAG_REQUESTED, &desc->flags);
1311 clear_bit(FLAG_OPEN_DRAIN, &desc->flags);
1312 clear_bit(FLAG_OPEN_SOURCE, &desc->flags);
1314 WARN_ON(extra_checks);
1316 spin_unlock_irqrestore(&gpio_lock, flags);
1318 EXPORT_SYMBOL_GPL(gpio_free);
1321 * gpio_request_one - request a single GPIO with initial configuration
1322 * @gpio: the GPIO number
1323 * @flags: GPIO configuration as specified by GPIOF_*
1324 * @label: a literal description string of this GPIO
1326 int gpio_request_one(unsigned gpio, unsigned long flags, const char *label)
1330 err = gpio_request(gpio, label);
1334 if (flags & GPIOF_OPEN_DRAIN)
1335 set_bit(FLAG_OPEN_DRAIN, &gpio_desc[gpio].flags);
1337 if (flags & GPIOF_OPEN_SOURCE)
1338 set_bit(FLAG_OPEN_SOURCE, &gpio_desc[gpio].flags);
1340 if (flags & GPIOF_DIR_IN)
1341 err = gpio_direction_input(gpio);
1343 err = gpio_direction_output(gpio,
1344 (flags & GPIOF_INIT_HIGH) ? 1 : 0);
1349 if (flags & GPIOF_EXPORT) {
1350 err = gpio_export(gpio, flags & GPIOF_EXPORT_CHANGEABLE);
1361 EXPORT_SYMBOL_GPL(gpio_request_one);
1364 * gpio_request_array - request multiple GPIOs in a single call
1365 * @array: array of the 'struct gpio'
1366 * @num: how many GPIOs in the array
1368 int gpio_request_array(const struct gpio *array, size_t num)
1372 for (i = 0; i < num; i++, array++) {
1373 err = gpio_request_one(array->gpio, array->flags, array->label);
1381 gpio_free((--array)->gpio);
1384 EXPORT_SYMBOL_GPL(gpio_request_array);
1387 * gpio_free_array - release multiple GPIOs in a single call
1388 * @array: array of the 'struct gpio'
1389 * @num: how many GPIOs in the array
1391 void gpio_free_array(const struct gpio *array, size_t num)
1394 gpio_free((array++)->gpio);
1396 EXPORT_SYMBOL_GPL(gpio_free_array);
1399 * gpiochip_is_requested - return string iff signal was requested
1400 * @chip: controller managing the signal
1401 * @offset: of signal within controller's 0..(ngpio - 1) range
1403 * Returns NULL if the GPIO is not currently requested, else a string.
1404 * If debugfs support is enabled, the string returned is the label passed
1405 * to gpio_request(); otherwise it is a meaningless constant.
1407 * This function is for use by GPIO controller drivers. The label can
1408 * help with diagnostics, and knowing that the signal is used as a GPIO
1409 * can help avoid accidentally multiplexing it to another controller.
1411 const char *gpiochip_is_requested(struct gpio_chip *chip, unsigned offset)
1413 unsigned gpio = chip->base + offset;
1415 if (!gpio_is_valid(gpio) || gpio_desc[gpio].chip != chip)
1417 if (test_bit(FLAG_REQUESTED, &gpio_desc[gpio].flags) == 0)
1419 #ifdef CONFIG_DEBUG_FS
1420 return gpio_desc[gpio].label;
1425 EXPORT_SYMBOL_GPL(gpiochip_is_requested);
1428 /* Drivers MUST set GPIO direction before making get/set calls. In
1429 * some cases this is done in early boot, before IRQs are enabled.
1431 * As a rule these aren't called more than once (except for drivers
1432 * using the open-drain emulation idiom) so these are natural places
1433 * to accumulate extra debugging checks. Note that we can't (yet)
1434 * rely on gpio_request() having been called beforehand.
1437 int gpio_direction_input(unsigned gpio)
1439 unsigned long flags;
1440 struct gpio_chip *chip;
1441 struct gpio_desc *desc = &gpio_desc[gpio];
1442 int status = -EINVAL;
1444 spin_lock_irqsave(&gpio_lock, flags);
1446 if (!gpio_is_valid(gpio))
1449 if (!chip || !chip->get || !chip->direction_input)
1452 if (gpio >= chip->ngpio)
1454 status = gpio_ensure_requested(desc, gpio);
1458 /* now we know the gpio is valid and chip won't vanish */
1460 spin_unlock_irqrestore(&gpio_lock, flags);
1462 might_sleep_if(chip->can_sleep);
1465 status = chip->request(chip, gpio);
1467 pr_debug("GPIO-%d: chip request fail, %d\n",
1468 chip->base + gpio, status);
1469 /* and it's not available to anyone else ...
1470 * gpio_request() is the fully clean solution.
1476 status = chip->direction_input(chip, gpio);
1478 clear_bit(FLAG_IS_OUT, &desc->flags);
1480 trace_gpio_direction(chip->base + gpio, 1, status);
1484 spin_unlock_irqrestore(&gpio_lock, flags);
1486 pr_debug("%s: gpio-%d status %d\n",
1487 __func__, gpio, status);
1490 EXPORT_SYMBOL_GPL(gpio_direction_input);
1492 int gpio_direction_output(unsigned gpio, int value)
1494 unsigned long flags;
1495 struct gpio_chip *chip;
1496 struct gpio_desc *desc = &gpio_desc[gpio];
1497 int status = -EINVAL;
1499 /* Open drain pin should not be driven to 1 */
1500 if (value && test_bit(FLAG_OPEN_DRAIN, &desc->flags))
1501 return gpio_direction_input(gpio);
1503 /* Open source pin should not be driven to 0 */
1504 if (!value && test_bit(FLAG_OPEN_SOURCE, &desc->flags))
1505 return gpio_direction_input(gpio);
1507 spin_lock_irqsave(&gpio_lock, flags);
1509 if (!gpio_is_valid(gpio))
1512 if (!chip || !chip->set || !chip->direction_output)
1515 if (gpio >= chip->ngpio)
1517 status = gpio_ensure_requested(desc, gpio);
1521 /* now we know the gpio is valid and chip won't vanish */
1523 spin_unlock_irqrestore(&gpio_lock, flags);
1525 might_sleep_if(chip->can_sleep);
1528 status = chip->request(chip, gpio);
1530 pr_debug("GPIO-%d: chip request fail, %d\n",
1531 chip->base + gpio, status);
1532 /* and it's not available to anyone else ...
1533 * gpio_request() is the fully clean solution.
1539 status = chip->direction_output(chip, gpio, value);
1541 set_bit(FLAG_IS_OUT, &desc->flags);
1542 trace_gpio_value(chip->base + gpio, 0, value);
1543 trace_gpio_direction(chip->base + gpio, 0, status);
1547 spin_unlock_irqrestore(&gpio_lock, flags);
1549 pr_debug("%s: gpio-%d status %d\n",
1550 __func__, gpio, status);
1553 EXPORT_SYMBOL_GPL(gpio_direction_output);
1556 * gpio_set_debounce - sets @debounce time for a @gpio
1557 * @gpio: the gpio to set debounce time
1558 * @debounce: debounce time is microseconds
1560 int gpio_set_debounce(unsigned gpio, unsigned debounce)
1562 unsigned long flags;
1563 struct gpio_chip *chip;
1564 struct gpio_desc *desc = &gpio_desc[gpio];
1565 int status = -EINVAL;
1567 spin_lock_irqsave(&gpio_lock, flags);
1569 if (!gpio_is_valid(gpio))
1572 if (!chip || !chip->set || !chip->set_debounce)
1575 if (gpio >= chip->ngpio)
1577 status = gpio_ensure_requested(desc, gpio);
1581 /* now we know the gpio is valid and chip won't vanish */
1583 spin_unlock_irqrestore(&gpio_lock, flags);
1585 might_sleep_if(chip->can_sleep);
1587 return chip->set_debounce(chip, gpio, debounce);
1590 spin_unlock_irqrestore(&gpio_lock, flags);
1592 pr_debug("%s: gpio-%d status %d\n",
1593 __func__, gpio, status);
1597 EXPORT_SYMBOL_GPL(gpio_set_debounce);
1599 /* I/O calls are only valid after configuration completed; the relevant
1600 * "is this a valid GPIO" error checks should already have been done.
1602 * "Get" operations are often inlinable as reading a pin value register,
1603 * and masking the relevant bit in that register.
1605 * When "set" operations are inlinable, they involve writing that mask to
1606 * one register to set a low value, or a different register to set it high.
1607 * Otherwise locking is needed, so there may be little value to inlining.
1609 *------------------------------------------------------------------------
1611 * IMPORTANT!!! The hot paths -- get/set value -- assume that callers
1612 * have requested the GPIO. That can include implicit requesting by
1613 * a direction setting call. Marking a gpio as requested locks its chip
1614 * in memory, guaranteeing that these table lookups need no more locking
1615 * and that gpiochip_remove() will fail.
1617 * REVISIT when debugging, consider adding some instrumentation to ensure
1618 * that the GPIO was actually requested.
1622 * __gpio_get_value() - return a gpio's value
1623 * @gpio: gpio whose value will be returned
1626 * This is used directly or indirectly to implement gpio_get_value().
1627 * It returns the zero or nonzero value provided by the associated
1628 * gpio_chip.get() method; or zero if no such method is provided.
1630 int __gpio_get_value(unsigned gpio)
1632 struct gpio_chip *chip;
1635 chip = gpio_to_chip(gpio);
1636 /* Should be using gpio_get_value_cansleep() */
1637 WARN_ON(chip->can_sleep);
1638 value = chip->get ? chip->get(chip, gpio - chip->base) : 0;
1639 trace_gpio_value(gpio, 1, value);
1642 EXPORT_SYMBOL_GPL(__gpio_get_value);
1645 * _gpio_set_open_drain_value() - Set the open drain gpio's value.
1646 * @gpio: Gpio whose state need to be set.
1648 * @value: Non-zero for setting it HIGH otherise it will set to LOW.
1650 static void _gpio_set_open_drain_value(unsigned gpio,
1651 struct gpio_chip *chip, int value)
1655 err = chip->direction_input(chip, gpio - chip->base);
1657 clear_bit(FLAG_IS_OUT, &gpio_desc[gpio].flags);
1659 err = chip->direction_output(chip, gpio - chip->base, 0);
1661 set_bit(FLAG_IS_OUT, &gpio_desc[gpio].flags);
1663 trace_gpio_direction(gpio, value, err);
1665 pr_err("%s: Error in set_value for open drain gpio%d err %d\n",
1666 __func__, gpio, err);
1670 * _gpio_set_open_source() - Set the open source gpio's value.
1671 * @gpio: Gpio whose state need to be set.
1673 * @value: Non-zero for setting it HIGH otherise it will set to LOW.
1675 static void _gpio_set_open_source_value(unsigned gpio,
1676 struct gpio_chip *chip, int value)
1680 err = chip->direction_output(chip, gpio - chip->base, 1);
1682 set_bit(FLAG_IS_OUT, &gpio_desc[gpio].flags);
1684 err = chip->direction_input(chip, gpio - chip->base);
1686 clear_bit(FLAG_IS_OUT, &gpio_desc[gpio].flags);
1688 trace_gpio_direction(gpio, !value, err);
1690 pr_err("%s: Error in set_value for open source gpio%d err %d\n",
1691 __func__, gpio, err);
1696 * __gpio_set_value() - assign a gpio's value
1697 * @gpio: gpio whose value will be assigned
1698 * @value: value to assign
1701 * This is used directly or indirectly to implement gpio_set_value().
1702 * It invokes the associated gpio_chip.set() method.
1704 void __gpio_set_value(unsigned gpio, int value)
1706 struct gpio_chip *chip;
1708 chip = gpio_to_chip(gpio);
1709 /* Should be using gpio_set_value_cansleep() */
1710 WARN_ON(chip->can_sleep);
1711 trace_gpio_value(gpio, 0, value);
1712 if (test_bit(FLAG_OPEN_DRAIN, &gpio_desc[gpio].flags))
1713 _gpio_set_open_drain_value(gpio, chip, value);
1714 else if (test_bit(FLAG_OPEN_SOURCE, &gpio_desc[gpio].flags))
1715 _gpio_set_open_source_value(gpio, chip, value);
1717 chip->set(chip, gpio - chip->base, value);
1719 EXPORT_SYMBOL_GPL(__gpio_set_value);
1722 * __gpio_cansleep() - report whether gpio value access will sleep
1723 * @gpio: gpio in question
1726 * This is used directly or indirectly to implement gpio_cansleep(). It
1727 * returns nonzero if access reading or writing the GPIO value can sleep.
1729 int __gpio_cansleep(unsigned gpio)
1731 struct gpio_chip *chip;
1733 /* only call this on GPIOs that are valid! */
1734 chip = gpio_to_chip(gpio);
1736 return chip->can_sleep;
1738 EXPORT_SYMBOL_GPL(__gpio_cansleep);
1741 * __gpio_to_irq() - return the IRQ corresponding to a GPIO
1742 * @gpio: gpio whose IRQ will be returned (already requested)
1745 * This is used directly or indirectly to implement gpio_to_irq().
1746 * It returns the number of the IRQ signaled by this (input) GPIO,
1747 * or a negative errno.
1749 int __gpio_to_irq(unsigned gpio)
1751 struct gpio_chip *chip;
1753 chip = gpio_to_chip(gpio);
1754 return chip->to_irq ? chip->to_irq(chip, gpio - chip->base) : -ENXIO;
1756 EXPORT_SYMBOL_GPL(__gpio_to_irq);
1760 /* There's no value in making it easy to inline GPIO calls that may sleep.
1761 * Common examples include ones connected to I2C or SPI chips.
1764 int gpio_get_value_cansleep(unsigned gpio)
1766 struct gpio_chip *chip;
1769 might_sleep_if(extra_checks);
1770 chip = gpio_to_chip(gpio);
1771 value = chip->get ? chip->get(chip, gpio - chip->base) : 0;
1772 trace_gpio_value(gpio, 1, value);
1775 EXPORT_SYMBOL_GPL(gpio_get_value_cansleep);
1777 void gpio_set_value_cansleep(unsigned gpio, int value)
1779 struct gpio_chip *chip;
1781 might_sleep_if(extra_checks);
1782 chip = gpio_to_chip(gpio);
1783 trace_gpio_value(gpio, 0, value);
1784 if (test_bit(FLAG_OPEN_DRAIN, &gpio_desc[gpio].flags))
1785 _gpio_set_open_drain_value(gpio, chip, value);
1786 else if (test_bit(FLAG_OPEN_SOURCE, &gpio_desc[gpio].flags))
1787 _gpio_set_open_source_value(gpio, chip, value);
1789 chip->set(chip, gpio - chip->base, value);
1791 EXPORT_SYMBOL_GPL(gpio_set_value_cansleep);
1794 #ifdef CONFIG_DEBUG_FS
1796 static void gpiolib_dbg_show(struct seq_file *s, struct gpio_chip *chip)
1799 unsigned gpio = chip->base;
1800 struct gpio_desc *gdesc = &gpio_desc[gpio];
1803 for (i = 0; i < chip->ngpio; i++, gpio++, gdesc++) {
1804 if (!test_bit(FLAG_REQUESTED, &gdesc->flags))
1807 gpio_get_direction(gpio);
1808 is_out = test_bit(FLAG_IS_OUT, &gdesc->flags);
1809 seq_printf(s, " gpio-%-3d (%-20.20s) %s %s",
1811 is_out ? "out" : "in ",
1813 ? (chip->get(chip, i) ? "hi" : "lo")
1815 seq_printf(s, "\n");
1819 static void *gpiolib_seq_start(struct seq_file *s, loff_t *pos)
1821 struct gpio_chip *chip = NULL;
1826 /* REVISIT this isn't locked against gpio_chip removal ... */
1828 for (gpio = 0; gpio_is_valid(gpio); gpio++) {
1829 if (gpio_desc[gpio].chip == chip)
1832 chip = gpio_desc[gpio].chip;
1836 if (index++ >= *pos) {
1847 static void *gpiolib_seq_next(struct seq_file *s, void *v, loff_t *pos)
1849 struct gpio_chip *chip = v;
1853 /* skip GPIOs provided by the current chip */
1854 for (gpio = chip->base + chip->ngpio; gpio_is_valid(gpio); gpio++) {
1855 chip = gpio_desc[gpio].chip;
1868 static void gpiolib_seq_stop(struct seq_file *s, void *v)
1872 static int gpiolib_seq_show(struct seq_file *s, void *v)
1874 struct gpio_chip *chip = v;
1877 seq_printf(s, "%sGPIOs %d-%d", (char *)s->private,
1878 chip->base, chip->base + chip->ngpio - 1);
1881 seq_printf(s, ", %s/%s", dev->bus ? dev->bus->name : "no-bus",
1884 seq_printf(s, ", %s", chip->label);
1885 if (chip->can_sleep)
1886 seq_printf(s, ", can sleep");
1887 seq_printf(s, ":\n");
1890 chip->dbg_show(s, chip);
1892 gpiolib_dbg_show(s, chip);
1897 static const struct seq_operations gpiolib_seq_ops = {
1898 .start = gpiolib_seq_start,
1899 .next = gpiolib_seq_next,
1900 .stop = gpiolib_seq_stop,
1901 .show = gpiolib_seq_show,
1904 static int gpiolib_open(struct inode *inode, struct file *file)
1906 return seq_open(file, &gpiolib_seq_ops);
1909 static const struct file_operations gpiolib_operations = {
1910 .owner = THIS_MODULE,
1911 .open = gpiolib_open,
1913 .llseek = seq_lseek,
1914 .release = seq_release,
1917 static int __init gpiolib_debugfs_init(void)
1919 /* /sys/kernel/debug/gpio */
1920 (void) debugfs_create_file("gpio", S_IFREG | S_IRUGO,
1921 NULL, NULL, &gpiolib_operations);
1924 subsys_initcall(gpiolib_debugfs_init);
1926 #endif /* DEBUG_FS */