1 #include <linux/kernel.h>
2 #include <linux/module.h>
3 #include <linux/interrupt.h>
5 #include <linux/spinlock.h>
6 #include <linux/list.h>
7 #include <linux/device.h>
9 #include <linux/debugfs.h>
10 #include <linux/seq_file.h>
11 #include <linux/gpio.h>
12 #include <linux/of_gpio.h>
13 #include <linux/idr.h>
14 #include <linux/slab.h>
16 #define CREATE_TRACE_POINTS
17 #include <trace/events/gpio.h>
19 /* Optional implementation infrastructure for GPIO interfaces.
21 * Platforms may want to use this if they tend to use very many GPIOs
22 * that aren't part of a System-On-Chip core; or across I2C/SPI/etc.
24 * When kernel footprint or instruction count is an issue, simpler
25 * implementations may be preferred. The GPIO programming interface
26 * allows for inlining speed-critical get/set operations for common
27 * cases, so that access to SOC-integrated GPIOs can sometimes cost
28 * only an instruction or two per bit.
32 /* When debugging, extend minimal trust to callers and platform code.
33 * Also emit diagnostic messages that may help initial bringup, when
34 * board setup or driver bugs are most common.
36 * Otherwise, minimize overhead in what may be bitbanging codepaths.
39 #define extra_checks 1
41 #define extra_checks 0
44 /* gpio_lock prevents conflicts during gpio_desc[] table updates.
45 * While any GPIO is requested, its gpio_chip is not removable;
46 * each GPIO's "requested" flag serves as a lock and refcount.
48 static DEFINE_SPINLOCK(gpio_lock);
51 struct gpio_chip *chip;
53 /* flag symbols are bit numbers */
54 #define FLAG_REQUESTED 0
56 #define FLAG_EXPORT 2 /* protected by sysfs_lock */
57 #define FLAG_SYSFS 3 /* exported via /sys/class/gpio/control */
58 #define FLAG_TRIG_FALL 4 /* trigger on falling edge */
59 #define FLAG_TRIG_RISE 5 /* trigger on rising edge */
60 #define FLAG_ACTIVE_LOW 6 /* sysfs value has active low */
61 #define FLAG_OPEN_DRAIN 7 /* Gpio is open drain type */
62 #define FLAG_OPEN_SOURCE 8 /* 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 #define GPIO_OFFSET_VALID(chip, offset) (offset >= 0 && offset < chip->ngpio)
77 static LIST_HEAD(gpio_chips);
79 #ifdef CONFIG_GPIO_SYSFS
80 static DEFINE_IDR(dirent_idr);
84 * Internal gpiod_* API using descriptors instead of the integer namespace.
85 * Most of this should eventually go public.
87 static int gpiod_request(struct gpio_desc *desc, const char *label);
88 static void gpiod_free(struct gpio_desc *desc);
89 static int gpiod_direction_input(struct gpio_desc *desc);
90 static int gpiod_direction_output(struct gpio_desc *desc, int value);
91 static int gpiod_get_direction(const struct gpio_desc *desc);
92 static int gpiod_set_debounce(struct gpio_desc *desc, unsigned debounce);
93 static int gpiod_get_value_cansleep(const struct gpio_desc *desc);
94 static void gpiod_set_value_cansleep(struct gpio_desc *desc, int value);
95 static int gpiod_get_value(const struct gpio_desc *desc);
96 static void gpiod_set_value(struct gpio_desc *desc, int value);
97 static int gpiod_cansleep(const struct gpio_desc *desc);
98 static int gpiod_to_irq(const struct gpio_desc *desc);
99 static int gpiod_export(struct gpio_desc *desc, bool direction_may_change);
100 static int gpiod_export_link(struct device *dev, const char *name,
101 struct gpio_desc *desc);
102 static int gpiod_sysfs_set_active_low(struct gpio_desc *desc, int value);
103 static void gpiod_unexport(struct gpio_desc *desc);
106 static inline void desc_set_label(struct gpio_desc *d, const char *label)
108 #ifdef CONFIG_DEBUG_FS
114 * Return the GPIO number of the passed descriptor relative to its chip
116 static int gpio_chip_hwgpio(const struct gpio_desc *desc)
118 return desc - &desc->chip->desc[0];
122 * Convert a GPIO number to its descriptor
124 static struct gpio_desc *gpio_to_desc(unsigned gpio)
126 if (WARN(!gpio_is_valid(gpio), "invalid GPIO %d\n", gpio))
129 return &gpio_desc[gpio];
133 * Convert a GPIO descriptor to the integer namespace.
134 * This should disappear in the future but is needed since we still
135 * use GPIO numbers for error messages and sysfs nodes
137 static int desc_to_gpio(const struct gpio_desc *desc)
139 return desc - &gpio_desc[0];
143 /* Warn when drivers omit gpio_request() calls -- legal but ill-advised
144 * when setting direction, and otherwise illegal. Until board setup code
145 * and drivers use explicit requests everywhere (which won't happen when
146 * those calls have no teeth) we can't avoid autorequesting. This nag
147 * message should motivate switching to explicit requests... so should
148 * the weaker cleanup after faults, compared to gpio_request().
150 * NOTE: the autorequest mechanism is going away; at this point it's
151 * only "legal" in the sense that (old) code using it won't break yet,
152 * but instead only triggers a WARN() stack dump.
154 static int gpio_ensure_requested(struct gpio_desc *desc)
156 const struct gpio_chip *chip = desc->chip;
157 const int gpio = desc_to_gpio(desc);
159 if (WARN(test_and_set_bit(FLAG_REQUESTED, &desc->flags) == 0,
160 "autorequest GPIO-%d\n", gpio)) {
161 if (!try_module_get(chip->owner)) {
162 pr_err("GPIO-%d: module can't be gotten \n", gpio);
163 clear_bit(FLAG_REQUESTED, &desc->flags);
167 desc_set_label(desc, "[auto]");
168 /* caller must chip->request() w/o spinlock */
175 static struct gpio_chip *gpiod_to_chip(const struct gpio_desc *desc)
177 return desc ? desc->chip : NULL;
180 /* caller holds gpio_lock *OR* gpio is marked as requested */
181 struct gpio_chip *gpio_to_chip(unsigned gpio)
183 return gpiod_to_chip(gpio_to_desc(gpio));
186 /* dynamic allocation of GPIOs, e.g. on a hotplugged device */
187 static int gpiochip_find_base(int ngpio)
189 struct gpio_chip *chip;
190 int base = ARCH_NR_GPIOS - ngpio;
192 list_for_each_entry_reverse(chip, &gpio_chips, list) {
193 /* found a free space? */
194 if (chip->base + chip->ngpio <= base)
197 /* nope, check the space right before the chip */
198 base = chip->base - ngpio;
201 if (gpio_is_valid(base)) {
202 pr_debug("%s: found new base at %d\n", __func__, base);
205 pr_err("%s: cannot find free range\n", __func__);
210 /* caller ensures gpio is valid and requested, chip->get_direction may sleep */
211 static int gpiod_get_direction(const struct gpio_desc *desc)
213 struct gpio_chip *chip;
215 int status = -EINVAL;
217 chip = gpiod_to_chip(desc);
218 offset = gpio_chip_hwgpio(desc);
220 if (!chip->get_direction)
223 status = chip->get_direction(chip, offset);
225 /* GPIOF_DIR_IN, or other positive */
227 /* FLAG_IS_OUT is just a cache of the result of get_direction(),
228 * so it does not affect constness per se */
229 clear_bit(FLAG_IS_OUT, &((struct gpio_desc *)desc)->flags);
233 set_bit(FLAG_IS_OUT, &((struct gpio_desc *)desc)->flags);
238 #ifdef CONFIG_GPIO_SYSFS
240 /* lock protects against unexport_gpio() being called while
241 * sysfs files are active.
243 static DEFINE_MUTEX(sysfs_lock);
246 * /sys/class/gpio/gpioN... only for GPIOs that are exported
248 * * MAY BE OMITTED if kernel won't allow direction changes
249 * * is read/write as "in" or "out"
250 * * may also be written as "high" or "low", initializing
251 * output value as specified ("out" implies "low")
253 * * always readable, subject to hardware behavior
254 * * may be writable, as zero/nonzero
256 * * configures behavior of poll(2) on /value
257 * * available only if pin can generate IRQs on input
258 * * is read/write as "none", "falling", "rising", or "both"
260 * * configures polarity of /value
261 * * is read/write as zero/nonzero
262 * * also affects existing and subsequent "falling" and "rising"
263 * /edge configuration
266 static ssize_t gpio_direction_show(struct device *dev,
267 struct device_attribute *attr, char *buf)
269 const struct gpio_desc *desc = dev_get_drvdata(dev);
272 mutex_lock(&sysfs_lock);
274 if (!test_bit(FLAG_EXPORT, &desc->flags)) {
277 gpiod_get_direction(desc);
278 status = sprintf(buf, "%s\n",
279 test_bit(FLAG_IS_OUT, &desc->flags)
283 mutex_unlock(&sysfs_lock);
287 static ssize_t gpio_direction_store(struct device *dev,
288 struct device_attribute *attr, const char *buf, size_t size)
290 struct gpio_desc *desc = dev_get_drvdata(dev);
293 mutex_lock(&sysfs_lock);
295 if (!test_bit(FLAG_EXPORT, &desc->flags))
297 else if (sysfs_streq(buf, "high"))
298 status = gpiod_direction_output(desc, 1);
299 else if (sysfs_streq(buf, "out") || sysfs_streq(buf, "low"))
300 status = gpiod_direction_output(desc, 0);
301 else if (sysfs_streq(buf, "in"))
302 status = gpiod_direction_input(desc);
306 mutex_unlock(&sysfs_lock);
307 return status ? : size;
310 static /* const */ DEVICE_ATTR(direction, 0644,
311 gpio_direction_show, gpio_direction_store);
313 static ssize_t gpio_value_show(struct device *dev,
314 struct device_attribute *attr, char *buf)
316 struct gpio_desc *desc = dev_get_drvdata(dev);
319 mutex_lock(&sysfs_lock);
321 if (!test_bit(FLAG_EXPORT, &desc->flags)) {
326 value = !!gpiod_get_value_cansleep(desc);
327 if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
330 status = sprintf(buf, "%d\n", value);
333 mutex_unlock(&sysfs_lock);
337 static ssize_t gpio_value_store(struct device *dev,
338 struct device_attribute *attr, const char *buf, size_t size)
340 struct gpio_desc *desc = dev_get_drvdata(dev);
343 mutex_lock(&sysfs_lock);
345 if (!test_bit(FLAG_EXPORT, &desc->flags))
347 else if (!test_bit(FLAG_IS_OUT, &desc->flags))
352 status = strict_strtol(buf, 0, &value);
354 if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
356 gpiod_set_value_cansleep(desc, value != 0);
361 mutex_unlock(&sysfs_lock);
365 static DEVICE_ATTR(value, 0644,
366 gpio_value_show, gpio_value_store);
368 static irqreturn_t gpio_sysfs_irq(int irq, void *priv)
370 struct sysfs_dirent *value_sd = priv;
372 sysfs_notify_dirent(value_sd);
376 static int gpio_setup_irq(struct gpio_desc *desc, struct device *dev,
377 unsigned long gpio_flags)
379 struct sysfs_dirent *value_sd;
380 unsigned long irq_flags;
383 if ((desc->flags & GPIO_TRIGGER_MASK) == gpio_flags)
386 irq = gpiod_to_irq(desc);
390 id = desc->flags >> ID_SHIFT;
391 value_sd = idr_find(&dirent_idr, id);
393 free_irq(irq, value_sd);
395 desc->flags &= ~GPIO_TRIGGER_MASK;
402 irq_flags = IRQF_SHARED;
403 if (test_bit(FLAG_TRIG_FALL, &gpio_flags))
404 irq_flags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ?
405 IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING;
406 if (test_bit(FLAG_TRIG_RISE, &gpio_flags))
407 irq_flags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ?
408 IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING;
411 value_sd = sysfs_get_dirent(dev->kobj.sd, NULL, "value");
417 ret = idr_alloc(&dirent_idr, value_sd, 1, 0, GFP_KERNEL);
422 desc->flags &= GPIO_FLAGS_MASK;
423 desc->flags |= (unsigned long)id << ID_SHIFT;
425 if (desc->flags >> ID_SHIFT != id) {
431 ret = request_any_context_irq(irq, gpio_sysfs_irq, irq_flags,
432 "gpiolib", value_sd);
436 desc->flags |= gpio_flags;
440 idr_remove(&dirent_idr, id);
441 desc->flags &= GPIO_FLAGS_MASK;
449 static const struct {
452 } trigger_types[] = {
454 { "falling", BIT(FLAG_TRIG_FALL) },
455 { "rising", BIT(FLAG_TRIG_RISE) },
456 { "both", BIT(FLAG_TRIG_FALL) | BIT(FLAG_TRIG_RISE) },
459 static ssize_t gpio_edge_show(struct device *dev,
460 struct device_attribute *attr, char *buf)
462 const struct gpio_desc *desc = dev_get_drvdata(dev);
465 mutex_lock(&sysfs_lock);
467 if (!test_bit(FLAG_EXPORT, &desc->flags))
473 for (i = 0; i < ARRAY_SIZE(trigger_types); i++)
474 if ((desc->flags & GPIO_TRIGGER_MASK)
475 == trigger_types[i].flags) {
476 status = sprintf(buf, "%s\n",
477 trigger_types[i].name);
482 mutex_unlock(&sysfs_lock);
486 static ssize_t gpio_edge_store(struct device *dev,
487 struct device_attribute *attr, const char *buf, size_t size)
489 struct gpio_desc *desc = dev_get_drvdata(dev);
493 for (i = 0; i < ARRAY_SIZE(trigger_types); i++)
494 if (sysfs_streq(trigger_types[i].name, buf))
499 mutex_lock(&sysfs_lock);
501 if (!test_bit(FLAG_EXPORT, &desc->flags))
504 status = gpio_setup_irq(desc, dev, trigger_types[i].flags);
509 mutex_unlock(&sysfs_lock);
514 static DEVICE_ATTR(edge, 0644, gpio_edge_show, gpio_edge_store);
516 static int sysfs_set_active_low(struct gpio_desc *desc, struct device *dev,
521 if (!!test_bit(FLAG_ACTIVE_LOW, &desc->flags) == !!value)
525 set_bit(FLAG_ACTIVE_LOW, &desc->flags);
527 clear_bit(FLAG_ACTIVE_LOW, &desc->flags);
529 /* reconfigure poll(2) support if enabled on one edge only */
530 if (dev != NULL && (!!test_bit(FLAG_TRIG_RISE, &desc->flags) ^
531 !!test_bit(FLAG_TRIG_FALL, &desc->flags))) {
532 unsigned long trigger_flags = desc->flags & GPIO_TRIGGER_MASK;
534 gpio_setup_irq(desc, dev, 0);
535 status = gpio_setup_irq(desc, dev, trigger_flags);
541 static ssize_t gpio_active_low_show(struct device *dev,
542 struct device_attribute *attr, char *buf)
544 const struct gpio_desc *desc = dev_get_drvdata(dev);
547 mutex_lock(&sysfs_lock);
549 if (!test_bit(FLAG_EXPORT, &desc->flags))
552 status = sprintf(buf, "%d\n",
553 !!test_bit(FLAG_ACTIVE_LOW, &desc->flags));
555 mutex_unlock(&sysfs_lock);
560 static ssize_t gpio_active_low_store(struct device *dev,
561 struct device_attribute *attr, const char *buf, size_t size)
563 struct gpio_desc *desc = dev_get_drvdata(dev);
566 mutex_lock(&sysfs_lock);
568 if (!test_bit(FLAG_EXPORT, &desc->flags)) {
573 status = strict_strtol(buf, 0, &value);
575 status = sysfs_set_active_low(desc, dev, value != 0);
578 mutex_unlock(&sysfs_lock);
580 return status ? : size;
583 static DEVICE_ATTR(active_low, 0644,
584 gpio_active_low_show, gpio_active_low_store);
586 static struct attribute *gpio_attrs[] = {
587 &dev_attr_value.attr,
588 &dev_attr_active_low.attr,
592 static const struct attribute_group gpio_attr_group = {
597 * /sys/class/gpio/gpiochipN/
598 * /base ... matching gpio_chip.base (N)
599 * /label ... matching gpio_chip.label
600 * /ngpio ... matching gpio_chip.ngpio
603 static ssize_t chip_base_show(struct device *dev,
604 struct device_attribute *attr, char *buf)
606 const struct gpio_chip *chip = dev_get_drvdata(dev);
608 return sprintf(buf, "%d\n", chip->base);
610 static DEVICE_ATTR(base, 0444, chip_base_show, NULL);
612 static ssize_t chip_label_show(struct device *dev,
613 struct device_attribute *attr, char *buf)
615 const struct gpio_chip *chip = dev_get_drvdata(dev);
617 return sprintf(buf, "%s\n", chip->label ? : "");
619 static DEVICE_ATTR(label, 0444, chip_label_show, NULL);
621 static ssize_t chip_ngpio_show(struct device *dev,
622 struct device_attribute *attr, char *buf)
624 const struct gpio_chip *chip = dev_get_drvdata(dev);
626 return sprintf(buf, "%u\n", chip->ngpio);
628 static DEVICE_ATTR(ngpio, 0444, chip_ngpio_show, NULL);
630 static struct attribute *gpiochip_attrs[] = {
632 &dev_attr_label.attr,
633 &dev_attr_ngpio.attr,
637 static const struct attribute_group gpiochip_attr_group = {
638 .attrs = gpiochip_attrs,
642 * /sys/class/gpio/export ... write-only
643 * integer N ... number of GPIO to export (full access)
644 * /sys/class/gpio/unexport ... write-only
645 * integer N ... number of GPIO to unexport
647 static ssize_t export_store(struct class *class,
648 struct class_attribute *attr,
649 const char *buf, size_t len)
652 struct gpio_desc *desc;
655 status = strict_strtol(buf, 0, &gpio);
659 desc = gpio_to_desc(gpio);
660 /* reject invalid GPIOs */
662 pr_warn("%s: invalid GPIO %ld\n", __func__, gpio);
666 /* No extra locking here; FLAG_SYSFS just signifies that the
667 * request and export were done by on behalf of userspace, so
668 * they may be undone on its behalf too.
671 status = gpiod_request(desc, "sysfs");
673 if (status == -EPROBE_DEFER)
677 status = gpiod_export(desc, true);
681 set_bit(FLAG_SYSFS, &desc->flags);
685 pr_debug("%s: status %d\n", __func__, status);
686 return status ? : len;
689 static ssize_t unexport_store(struct class *class,
690 struct class_attribute *attr,
691 const char *buf, size_t len)
694 struct gpio_desc *desc;
697 status = strict_strtol(buf, 0, &gpio);
701 desc = gpio_to_desc(gpio);
702 /* reject bogus commands (gpio_unexport ignores them) */
704 pr_warn("%s: invalid GPIO %ld\n", __func__, gpio);
710 /* No extra locking here; FLAG_SYSFS just signifies that the
711 * request and export were done by on behalf of userspace, so
712 * they may be undone on its behalf too.
714 if (test_and_clear_bit(FLAG_SYSFS, &desc->flags)) {
720 pr_debug("%s: status %d\n", __func__, status);
721 return status ? : len;
724 static struct class_attribute gpio_class_attrs[] = {
725 __ATTR(export, 0200, NULL, export_store),
726 __ATTR(unexport, 0200, NULL, unexport_store),
730 static struct class gpio_class = {
732 .owner = THIS_MODULE,
734 .class_attrs = gpio_class_attrs,
739 * gpio_export - export a GPIO through sysfs
740 * @gpio: gpio to make available, already requested
741 * @direction_may_change: true if userspace may change gpio direction
742 * Context: arch_initcall or later
744 * When drivers want to make a GPIO accessible to userspace after they
745 * have requested it -- perhaps while debugging, or as part of their
746 * public interface -- they may use this routine. If the GPIO can
747 * change direction (some can't) and the caller allows it, userspace
748 * will see "direction" sysfs attribute which may be used to change
749 * the gpio's direction. A "value" attribute will always be provided.
751 * Returns zero on success, else an error.
753 static int gpiod_export(struct gpio_desc *desc, bool direction_may_change)
755 struct gpio_chip *chip;
758 const char *ioname = NULL;
762 /* can't export until sysfs is available ... */
764 pr_debug("%s: called too early!\n", __func__);
769 pr_debug("%s: invalid gpio descriptor\n", __func__);
775 mutex_lock(&sysfs_lock);
777 /* check if chip is being removed */
778 if (!chip || !chip->exported) {
783 spin_lock_irqsave(&gpio_lock, flags);
784 if (!test_bit(FLAG_REQUESTED, &desc->flags) ||
785 test_bit(FLAG_EXPORT, &desc->flags)) {
786 spin_unlock_irqrestore(&gpio_lock, flags);
787 pr_debug("%s: gpio %d unavailable (requested=%d, exported=%d)\n",
788 __func__, desc_to_gpio(desc),
789 test_bit(FLAG_REQUESTED, &desc->flags),
790 test_bit(FLAG_EXPORT, &desc->flags));
795 if (!desc->chip->direction_input || !desc->chip->direction_output)
796 direction_may_change = false;
797 spin_unlock_irqrestore(&gpio_lock, flags);
799 offset = gpio_chip_hwgpio(desc);
800 if (desc->chip->names && desc->chip->names[offset])
801 ioname = desc->chip->names[offset];
803 dev = device_create(&gpio_class, desc->chip->dev, MKDEV(0, 0),
804 desc, ioname ? ioname : "gpio%u",
807 status = PTR_ERR(dev);
811 status = sysfs_create_group(&dev->kobj, &gpio_attr_group);
813 goto fail_unregister_device;
815 if (direction_may_change) {
816 status = device_create_file(dev, &dev_attr_direction);
818 goto fail_remove_attr_group;
821 if (gpiod_to_irq(desc) >= 0 && (direction_may_change ||
822 !test_bit(FLAG_IS_OUT, &desc->flags))) {
823 status = device_create_file(dev, &dev_attr_edge);
825 goto fail_remove_attr_direction;
828 set_bit(FLAG_EXPORT, &desc->flags);
829 mutex_unlock(&sysfs_lock);
832 fail_remove_attr_direction:
833 device_remove_file(dev, &dev_attr_direction);
834 fail_remove_attr_group:
835 sysfs_remove_group(&dev->kobj, &gpio_attr_group);
836 fail_unregister_device:
837 device_unregister(dev);
839 mutex_unlock(&sysfs_lock);
840 pr_debug("%s: gpio%d status %d\n", __func__, desc_to_gpio(desc),
845 int gpio_export(unsigned gpio, bool direction_may_change)
847 return gpiod_export(gpio_to_desc(gpio), direction_may_change);
849 EXPORT_SYMBOL_GPL(gpio_export);
851 static int match_export(struct device *dev, const void *data)
853 return dev_get_drvdata(dev) == data;
857 * gpio_export_link - create a sysfs link to an exported GPIO node
858 * @dev: device under which to create symlink
859 * @name: name of the symlink
860 * @gpio: gpio to create symlink to, already exported
862 * Set up a symlink from /sys/.../dev/name to /sys/class/gpio/gpioN
863 * node. Caller is responsible for unlinking.
865 * Returns zero on success, else an error.
867 static int gpiod_export_link(struct device *dev, const char *name,
868 struct gpio_desc *desc)
870 int status = -EINVAL;
873 pr_warn("%s: invalid GPIO\n", __func__);
877 mutex_lock(&sysfs_lock);
879 if (test_bit(FLAG_EXPORT, &desc->flags)) {
882 tdev = class_find_device(&gpio_class, NULL, desc, match_export);
884 status = sysfs_create_link(&dev->kobj, &tdev->kobj,
892 mutex_unlock(&sysfs_lock);
895 pr_debug("%s: gpio%d status %d\n", __func__, desc_to_gpio(desc),
901 int gpio_export_link(struct device *dev, const char *name, unsigned gpio)
903 return gpiod_export_link(dev, name, gpio_to_desc(gpio));
905 EXPORT_SYMBOL_GPL(gpio_export_link);
908 * gpio_sysfs_set_active_low - set the polarity of gpio sysfs value
909 * @gpio: gpio to change
910 * @value: non-zero to use active low, i.e. inverted values
912 * Set the polarity of /sys/class/gpio/gpioN/value sysfs attribute.
913 * The GPIO does not have to be exported yet. If poll(2) support has
914 * been enabled for either rising or falling edge, it will be
915 * reconfigured to follow the new polarity.
917 * Returns zero on success, else an error.
919 static int gpiod_sysfs_set_active_low(struct gpio_desc *desc, int value)
921 struct device *dev = NULL;
922 int status = -EINVAL;
925 pr_warn("%s: invalid GPIO\n", __func__);
929 mutex_lock(&sysfs_lock);
931 if (test_bit(FLAG_EXPORT, &desc->flags)) {
932 dev = class_find_device(&gpio_class, NULL, desc, match_export);
939 status = sysfs_set_active_low(desc, dev, value);
942 mutex_unlock(&sysfs_lock);
945 pr_debug("%s: gpio%d status %d\n", __func__, desc_to_gpio(desc),
951 int gpio_sysfs_set_active_low(unsigned gpio, int value)
953 return gpiod_sysfs_set_active_low(gpio_to_desc(gpio), value);
955 EXPORT_SYMBOL_GPL(gpio_sysfs_set_active_low);
958 * gpio_unexport - reverse effect of gpio_export()
959 * @gpio: gpio to make unavailable
961 * This is implicit on gpio_free().
963 static void gpiod_unexport(struct gpio_desc *desc)
966 struct device *dev = NULL;
969 pr_warn("%s: invalid GPIO\n", __func__);
973 mutex_lock(&sysfs_lock);
975 if (test_bit(FLAG_EXPORT, &desc->flags)) {
977 dev = class_find_device(&gpio_class, NULL, desc, match_export);
979 gpio_setup_irq(desc, dev, 0);
980 clear_bit(FLAG_EXPORT, &desc->flags);
985 mutex_unlock(&sysfs_lock);
988 device_remove_file(dev, &dev_attr_edge);
989 device_remove_file(dev, &dev_attr_direction);
990 sysfs_remove_group(&dev->kobj, &gpio_attr_group);
991 device_unregister(dev);
996 pr_debug("%s: gpio%d status %d\n", __func__, desc_to_gpio(desc),
1000 void gpio_unexport(unsigned gpio)
1002 gpiod_unexport(gpio_to_desc(gpio));
1004 EXPORT_SYMBOL_GPL(gpio_unexport);
1006 static int gpiochip_export(struct gpio_chip *chip)
1011 /* Many systems register gpio chips for SOC support very early,
1012 * before driver model support is available. In those cases we
1013 * export this later, in gpiolib_sysfs_init() ... here we just
1014 * verify that _some_ field of gpio_class got initialized.
1019 /* use chip->base for the ID; it's already known to be unique */
1020 mutex_lock(&sysfs_lock);
1021 dev = device_create(&gpio_class, chip->dev, MKDEV(0, 0), chip,
1022 "gpiochip%d", chip->base);
1024 status = sysfs_create_group(&dev->kobj,
1025 &gpiochip_attr_group);
1027 status = PTR_ERR(dev);
1028 chip->exported = (status == 0);
1029 mutex_unlock(&sysfs_lock);
1032 unsigned long flags;
1035 spin_lock_irqsave(&gpio_lock, flags);
1037 while (gpio < chip->ngpio)
1038 chip->desc[gpio++].chip = NULL;
1039 spin_unlock_irqrestore(&gpio_lock, flags);
1041 pr_debug("%s: chip %s status %d\n", __func__,
1042 chip->label, status);
1048 static void gpiochip_unexport(struct gpio_chip *chip)
1052 struct gpio_desc *desc;
1055 mutex_lock(&sysfs_lock);
1056 dev = class_find_device(&gpio_class, NULL, chip, match_export);
1058 sysfs_remove_group(&dev->kobj, &gpiochip_attr_group);
1060 device_unregister(dev);
1061 /* prevent further gpiod exports */
1066 mutex_unlock(&sysfs_lock);
1069 pr_debug("%s: chip %s status %d\n", __func__,
1070 chip->label, status);
1072 /* unregister gpiod class devices owned by sysfs */
1073 for (i = 0; i < chip->ngpio; i++) {
1074 desc = &chip->desc[i];
1075 if (test_and_clear_bit(FLAG_SYSFS, &desc->flags))
1080 static int __init gpiolib_sysfs_init(void)
1083 unsigned long flags;
1084 struct gpio_chip *chip;
1086 status = class_register(&gpio_class);
1090 /* Scan and register the gpio_chips which registered very
1091 * early (e.g. before the class_register above was called).
1093 * We run before arch_initcall() so chip->dev nodes can have
1094 * registered, and so arch_initcall() can always gpio_export().
1096 spin_lock_irqsave(&gpio_lock, flags);
1097 list_for_each_entry(chip, &gpio_chips, list) {
1098 if (!chip || chip->exported)
1101 spin_unlock_irqrestore(&gpio_lock, flags);
1102 status = gpiochip_export(chip);
1103 spin_lock_irqsave(&gpio_lock, flags);
1105 spin_unlock_irqrestore(&gpio_lock, flags);
1110 postcore_initcall(gpiolib_sysfs_init);
1113 static inline int gpiochip_export(struct gpio_chip *chip)
1118 static inline void gpiochip_unexport(struct gpio_chip *chip)
1122 static inline int gpiod_export(struct gpio_desc *desc,
1123 bool direction_may_change)
1128 static inline int gpiod_export_link(struct device *dev, const char *name,
1129 struct gpio_desc *desc)
1134 static inline int gpiod_sysfs_set_active_low(struct gpio_desc *desc, int value)
1139 static inline void gpiod_unexport(struct gpio_desc *desc)
1143 #endif /* CONFIG_GPIO_SYSFS */
1146 * Add a new chip to the global chips list, keeping the list of chips sorted
1149 * Return -EBUSY if the new chip overlaps with some other chip's integer
1152 static int gpiochip_add_to_list(struct gpio_chip *chip)
1154 struct list_head *pos = &gpio_chips;
1155 struct gpio_chip *_chip;
1158 /* find where to insert our chip */
1159 list_for_each(pos, &gpio_chips) {
1160 _chip = list_entry(pos, struct gpio_chip, list);
1161 /* shall we insert before _chip? */
1162 if (_chip->base >= chip->base + chip->ngpio)
1166 /* are we stepping on the chip right before? */
1167 if (pos != &gpio_chips && pos->prev != &gpio_chips) {
1168 _chip = list_entry(pos->prev, struct gpio_chip, list);
1169 if (_chip->base + _chip->ngpio > chip->base) {
1171 "GPIO integer space overlap, cannot add chip\n");
1177 list_add_tail(&chip->list, pos);
1183 * gpiochip_add() - register a gpio_chip
1184 * @chip: the chip to register, with chip->base initialized
1185 * Context: potentially before irqs or kmalloc will work
1187 * Returns a negative errno if the chip can't be registered, such as
1188 * because the chip->base is invalid or already associated with a
1189 * different chip. Otherwise it returns zero as a success code.
1191 * When gpiochip_add() is called very early during boot, so that GPIOs
1192 * can be freely used, the chip->dev device must be registered before
1193 * the gpio framework's arch_initcall(). Otherwise sysfs initialization
1194 * for GPIOs will fail rudely.
1196 * If chip->base is negative, this requests dynamic assignment of
1197 * a range of valid GPIOs.
1199 int gpiochip_add(struct gpio_chip *chip)
1201 unsigned long flags;
1204 int base = chip->base;
1206 if ((!gpio_is_valid(base) || !gpio_is_valid(base + chip->ngpio - 1))
1212 spin_lock_irqsave(&gpio_lock, flags);
1215 base = gpiochip_find_base(chip->ngpio);
1223 status = gpiochip_add_to_list(chip);
1226 chip->desc = &gpio_desc[chip->base];
1228 for (id = 0; id < chip->ngpio; id++) {
1229 struct gpio_desc *desc = &chip->desc[id];
1232 /* REVISIT: most hardware initializes GPIOs as
1233 * inputs (often with pullups enabled) so power
1234 * usage is minimized. Linux code should set the
1235 * gpio direction first thing; but until it does,
1236 * and in case chip->get_direction is not set,
1237 * we may expose the wrong direction in sysfs.
1239 desc->flags = !chip->direction_input
1240 ? (1 << FLAG_IS_OUT)
1245 spin_unlock_irqrestore(&gpio_lock, flags);
1247 #ifdef CONFIG_PINCTRL
1248 INIT_LIST_HEAD(&chip->pin_ranges);
1251 of_gpiochip_add(chip);
1256 status = gpiochip_export(chip);
1260 pr_debug("gpiochip_add: registered GPIOs %d to %d on device: %s\n",
1261 chip->base, chip->base + chip->ngpio - 1,
1262 chip->label ? : "generic");
1267 spin_unlock_irqrestore(&gpio_lock, flags);
1269 /* failures here can mean systems won't boot... */
1270 pr_err("gpiochip_add: gpios %d..%d (%s) failed to register\n",
1271 chip->base, chip->base + chip->ngpio - 1,
1272 chip->label ? : "generic");
1275 EXPORT_SYMBOL_GPL(gpiochip_add);
1278 * gpiochip_remove() - unregister a gpio_chip
1279 * @chip: the chip to unregister
1281 * A gpio_chip with any GPIOs still requested may not be removed.
1283 int gpiochip_remove(struct gpio_chip *chip)
1285 unsigned long flags;
1289 gpiochip_unexport(chip);
1291 spin_lock_irqsave(&gpio_lock, flags);
1293 gpiochip_remove_pin_ranges(chip);
1294 of_gpiochip_remove(chip);
1296 for (id = 0; id < chip->ngpio; id++) {
1297 if (test_bit(FLAG_REQUESTED, &chip->desc[id].flags)) {
1303 for (id = 0; id < chip->ngpio; id++)
1304 chip->desc[id].chip = NULL;
1306 list_del(&chip->list);
1309 spin_unlock_irqrestore(&gpio_lock, flags);
1313 EXPORT_SYMBOL_GPL(gpiochip_remove);
1316 * gpiochip_find() - iterator for locating a specific gpio_chip
1317 * @data: data to pass to match function
1318 * @callback: Callback function to check gpio_chip
1320 * Similar to bus_find_device. It returns a reference to a gpio_chip as
1321 * determined by a user supplied @match callback. The callback should return
1322 * 0 if the device doesn't match and non-zero if it does. If the callback is
1323 * non-zero, this function will return to the caller and not iterate over any
1326 struct gpio_chip *gpiochip_find(void *data,
1327 int (*match)(struct gpio_chip *chip,
1330 struct gpio_chip *chip;
1331 unsigned long flags;
1333 spin_lock_irqsave(&gpio_lock, flags);
1334 list_for_each_entry(chip, &gpio_chips, list)
1335 if (match(chip, data))
1339 if (&chip->list == &gpio_chips)
1341 spin_unlock_irqrestore(&gpio_lock, flags);
1345 EXPORT_SYMBOL_GPL(gpiochip_find);
1347 #ifdef CONFIG_PINCTRL
1350 * gpiochip_add_pin_range() - add a range for GPIO <-> pin mapping
1351 * @chip: the gpiochip to add the range for
1352 * @pinctrl_name: the dev_name() of the pin controller to map to
1353 * @gpio_offset: the start offset in the current gpio_chip number space
1354 * @pin_offset: the start offset in the pin controller number space
1355 * @npins: the number of pins from the offset of each pin space (GPIO and
1356 * pin controller) to accumulate in this range
1358 int gpiochip_add_pin_range(struct gpio_chip *chip, const char *pinctl_name,
1359 unsigned int gpio_offset, unsigned int pin_offset,
1362 struct gpio_pin_range *pin_range;
1365 pin_range = kzalloc(sizeof(*pin_range), GFP_KERNEL);
1367 pr_err("%s: GPIO chip: failed to allocate pin ranges\n",
1372 /* Use local offset as range ID */
1373 pin_range->range.id = gpio_offset;
1374 pin_range->range.gc = chip;
1375 pin_range->range.name = chip->label;
1376 pin_range->range.base = chip->base + gpio_offset;
1377 pin_range->range.pin_base = pin_offset;
1378 pin_range->range.npins = npins;
1379 pin_range->pctldev = pinctrl_find_and_add_gpio_range(pinctl_name,
1381 if (IS_ERR(pin_range->pctldev)) {
1382 ret = PTR_ERR(pin_range->pctldev);
1383 pr_err("%s: GPIO chip: could not create pin range\n",
1388 pr_debug("GPIO chip %s: created GPIO range %d->%d ==> %s PIN %d->%d\n",
1389 chip->label, gpio_offset, gpio_offset + npins - 1,
1391 pin_offset, pin_offset + npins - 1);
1393 list_add_tail(&pin_range->node, &chip->pin_ranges);
1397 EXPORT_SYMBOL_GPL(gpiochip_add_pin_range);
1400 * gpiochip_remove_pin_ranges() - remove all the GPIO <-> pin mappings
1401 * @chip: the chip to remove all the mappings for
1403 void gpiochip_remove_pin_ranges(struct gpio_chip *chip)
1405 struct gpio_pin_range *pin_range, *tmp;
1407 list_for_each_entry_safe(pin_range, tmp, &chip->pin_ranges, node) {
1408 list_del(&pin_range->node);
1409 pinctrl_remove_gpio_range(pin_range->pctldev,
1414 EXPORT_SYMBOL_GPL(gpiochip_remove_pin_ranges);
1416 #endif /* CONFIG_PINCTRL */
1418 /* These "optional" allocation calls help prevent drivers from stomping
1419 * on each other, and help provide better diagnostics in debugfs.
1420 * They're called even less than the "set direction" calls.
1422 static int gpiod_request(struct gpio_desc *desc, const char *label)
1424 struct gpio_chip *chip;
1425 int status = -EPROBE_DEFER;
1426 unsigned long flags;
1429 pr_warn("%s: invalid GPIO\n", __func__);
1433 spin_lock_irqsave(&gpio_lock, flags);
1439 if (!try_module_get(chip->owner))
1442 /* NOTE: gpio_request() can be called in early boot,
1443 * before IRQs are enabled, for non-sleeping (SOC) GPIOs.
1446 if (test_and_set_bit(FLAG_REQUESTED, &desc->flags) == 0) {
1447 desc_set_label(desc, label ? : "?");
1451 module_put(chip->owner);
1455 if (chip->request) {
1456 /* chip->request may sleep */
1457 spin_unlock_irqrestore(&gpio_lock, flags);
1458 status = chip->request(chip, gpio_chip_hwgpio(desc));
1459 spin_lock_irqsave(&gpio_lock, flags);
1462 desc_set_label(desc, NULL);
1463 module_put(chip->owner);
1464 clear_bit(FLAG_REQUESTED, &desc->flags);
1468 if (chip->get_direction) {
1469 /* chip->get_direction may sleep */
1470 spin_unlock_irqrestore(&gpio_lock, flags);
1471 gpiod_get_direction(desc);
1472 spin_lock_irqsave(&gpio_lock, flags);
1476 pr_debug("_gpio_request: gpio-%d (%s) status %d\n",
1477 desc_to_gpio(desc), label ? : "?", status);
1478 spin_unlock_irqrestore(&gpio_lock, flags);
1482 int gpio_request(unsigned gpio, const char *label)
1484 return gpiod_request(gpio_to_desc(gpio), label);
1486 EXPORT_SYMBOL_GPL(gpio_request);
1488 static void gpiod_free(struct gpio_desc *desc)
1490 unsigned long flags;
1491 struct gpio_chip *chip;
1496 WARN_ON(extra_checks);
1500 gpiod_unexport(desc);
1502 spin_lock_irqsave(&gpio_lock, flags);
1505 if (chip && test_bit(FLAG_REQUESTED, &desc->flags)) {
1507 spin_unlock_irqrestore(&gpio_lock, flags);
1508 might_sleep_if(chip->can_sleep);
1509 chip->free(chip, gpio_chip_hwgpio(desc));
1510 spin_lock_irqsave(&gpio_lock, flags);
1512 desc_set_label(desc, NULL);
1513 module_put(desc->chip->owner);
1514 clear_bit(FLAG_ACTIVE_LOW, &desc->flags);
1515 clear_bit(FLAG_REQUESTED, &desc->flags);
1516 clear_bit(FLAG_OPEN_DRAIN, &desc->flags);
1517 clear_bit(FLAG_OPEN_SOURCE, &desc->flags);
1519 WARN_ON(extra_checks);
1521 spin_unlock_irqrestore(&gpio_lock, flags);
1524 void gpio_free(unsigned gpio)
1526 gpiod_free(gpio_to_desc(gpio));
1528 EXPORT_SYMBOL_GPL(gpio_free);
1531 * gpio_request_one - request a single GPIO with initial configuration
1532 * @gpio: the GPIO number
1533 * @flags: GPIO configuration as specified by GPIOF_*
1534 * @label: a literal description string of this GPIO
1536 int gpio_request_one(unsigned gpio, unsigned long flags, const char *label)
1538 struct gpio_desc *desc;
1541 desc = gpio_to_desc(gpio);
1543 err = gpiod_request(desc, label);
1547 if (flags & GPIOF_OPEN_DRAIN)
1548 set_bit(FLAG_OPEN_DRAIN, &desc->flags);
1550 if (flags & GPIOF_OPEN_SOURCE)
1551 set_bit(FLAG_OPEN_SOURCE, &desc->flags);
1553 if (flags & GPIOF_DIR_IN)
1554 err = gpiod_direction_input(desc);
1556 err = gpiod_direction_output(desc,
1557 (flags & GPIOF_INIT_HIGH) ? 1 : 0);
1562 if (flags & GPIOF_EXPORT) {
1563 err = gpiod_export(desc, flags & GPIOF_EXPORT_CHANGEABLE);
1574 EXPORT_SYMBOL_GPL(gpio_request_one);
1577 * gpio_request_array - request multiple GPIOs in a single call
1578 * @array: array of the 'struct gpio'
1579 * @num: how many GPIOs in the array
1581 int gpio_request_array(const struct gpio *array, size_t num)
1585 for (i = 0; i < num; i++, array++) {
1586 err = gpio_request_one(array->gpio, array->flags, array->label);
1594 gpio_free((--array)->gpio);
1597 EXPORT_SYMBOL_GPL(gpio_request_array);
1600 * gpio_free_array - release multiple GPIOs in a single call
1601 * @array: array of the 'struct gpio'
1602 * @num: how many GPIOs in the array
1604 void gpio_free_array(const struct gpio *array, size_t num)
1607 gpio_free((array++)->gpio);
1609 EXPORT_SYMBOL_GPL(gpio_free_array);
1612 * gpiochip_is_requested - return string iff signal was requested
1613 * @chip: controller managing the signal
1614 * @offset: of signal within controller's 0..(ngpio - 1) range
1616 * Returns NULL if the GPIO is not currently requested, else a string.
1617 * If debugfs support is enabled, the string returned is the label passed
1618 * to gpio_request(); otherwise it is a meaningless constant.
1620 * This function is for use by GPIO controller drivers. The label can
1621 * help with diagnostics, and knowing that the signal is used as a GPIO
1622 * can help avoid accidentally multiplexing it to another controller.
1624 const char *gpiochip_is_requested(struct gpio_chip *chip, unsigned offset)
1626 struct gpio_desc *desc;
1628 if (!GPIO_OFFSET_VALID(chip, offset))
1631 desc = &chip->desc[offset];
1633 if (test_bit(FLAG_REQUESTED, &desc->flags) == 0)
1635 #ifdef CONFIG_DEBUG_FS
1641 EXPORT_SYMBOL_GPL(gpiochip_is_requested);
1644 /* Drivers MUST set GPIO direction before making get/set calls. In
1645 * some cases this is done in early boot, before IRQs are enabled.
1647 * As a rule these aren't called more than once (except for drivers
1648 * using the open-drain emulation idiom) so these are natural places
1649 * to accumulate extra debugging checks. Note that we can't (yet)
1650 * rely on gpio_request() having been called beforehand.
1653 static int gpiod_direction_input(struct gpio_desc *desc)
1655 unsigned long flags;
1656 struct gpio_chip *chip;
1657 int status = -EINVAL;
1661 pr_warn("%s: invalid GPIO\n", __func__);
1665 spin_lock_irqsave(&gpio_lock, flags);
1668 if (!chip || !chip->get || !chip->direction_input)
1670 status = gpio_ensure_requested(desc);
1674 /* now we know the gpio is valid and chip won't vanish */
1676 spin_unlock_irqrestore(&gpio_lock, flags);
1678 might_sleep_if(chip->can_sleep);
1680 offset = gpio_chip_hwgpio(desc);
1682 status = chip->request(chip, offset);
1684 pr_debug("GPIO-%d: chip request fail, %d\n",
1685 desc_to_gpio(desc), status);
1686 /* and it's not available to anyone else ...
1687 * gpio_request() is the fully clean solution.
1693 status = chip->direction_input(chip, offset);
1695 clear_bit(FLAG_IS_OUT, &desc->flags);
1697 trace_gpio_direction(desc_to_gpio(desc), 1, status);
1701 spin_unlock_irqrestore(&gpio_lock, flags);
1703 pr_debug("%s: gpio-%d status %d\n", __func__,
1704 desc_to_gpio(desc), status);
1708 int gpio_direction_input(unsigned gpio)
1710 return gpiod_direction_input(gpio_to_desc(gpio));
1712 EXPORT_SYMBOL_GPL(gpio_direction_input);
1714 static int gpiod_direction_output(struct gpio_desc *desc, int value)
1716 unsigned long flags;
1717 struct gpio_chip *chip;
1718 int status = -EINVAL;
1722 pr_warn("%s: invalid GPIO\n", __func__);
1726 /* Open drain pin should not be driven to 1 */
1727 if (value && test_bit(FLAG_OPEN_DRAIN, &desc->flags))
1728 return gpiod_direction_input(desc);
1730 /* Open source pin should not be driven to 0 */
1731 if (!value && test_bit(FLAG_OPEN_SOURCE, &desc->flags))
1732 return gpiod_direction_input(desc);
1734 spin_lock_irqsave(&gpio_lock, flags);
1737 if (!chip || !chip->set || !chip->direction_output)
1739 status = gpio_ensure_requested(desc);
1743 /* now we know the gpio is valid and chip won't vanish */
1745 spin_unlock_irqrestore(&gpio_lock, flags);
1747 might_sleep_if(chip->can_sleep);
1749 offset = gpio_chip_hwgpio(desc);
1751 status = chip->request(chip, offset);
1753 pr_debug("GPIO-%d: chip request fail, %d\n",
1754 desc_to_gpio(desc), status);
1755 /* and it's not available to anyone else ...
1756 * gpio_request() is the fully clean solution.
1762 status = chip->direction_output(chip, offset, value);
1764 set_bit(FLAG_IS_OUT, &desc->flags);
1765 trace_gpio_value(desc_to_gpio(desc), 0, value);
1766 trace_gpio_direction(desc_to_gpio(desc), 0, status);
1770 spin_unlock_irqrestore(&gpio_lock, flags);
1772 pr_debug("%s: gpio-%d status %d\n", __func__,
1773 desc_to_gpio(desc), status);
1777 int gpio_direction_output(unsigned gpio, int value)
1779 return gpiod_direction_output(gpio_to_desc(gpio), value);
1781 EXPORT_SYMBOL_GPL(gpio_direction_output);
1784 * gpio_set_debounce - sets @debounce time for a @gpio
1785 * @gpio: the gpio to set debounce time
1786 * @debounce: debounce time is microseconds
1788 static int gpiod_set_debounce(struct gpio_desc *desc, unsigned debounce)
1790 unsigned long flags;
1791 struct gpio_chip *chip;
1792 int status = -EINVAL;
1796 pr_warn("%s: invalid GPIO\n", __func__);
1800 spin_lock_irqsave(&gpio_lock, flags);
1803 if (!chip || !chip->set || !chip->set_debounce)
1806 status = gpio_ensure_requested(desc);
1810 /* now we know the gpio is valid and chip won't vanish */
1812 spin_unlock_irqrestore(&gpio_lock, flags);
1814 might_sleep_if(chip->can_sleep);
1816 offset = gpio_chip_hwgpio(desc);
1817 return chip->set_debounce(chip, offset, debounce);
1820 spin_unlock_irqrestore(&gpio_lock, flags);
1822 pr_debug("%s: gpio-%d status %d\n", __func__,
1823 desc_to_gpio(desc), status);
1828 int gpio_set_debounce(unsigned gpio, unsigned debounce)
1830 return gpiod_set_debounce(gpio_to_desc(gpio), debounce);
1832 EXPORT_SYMBOL_GPL(gpio_set_debounce);
1834 /* I/O calls are only valid after configuration completed; the relevant
1835 * "is this a valid GPIO" error checks should already have been done.
1837 * "Get" operations are often inlinable as reading a pin value register,
1838 * and masking the relevant bit in that register.
1840 * When "set" operations are inlinable, they involve writing that mask to
1841 * one register to set a low value, or a different register to set it high.
1842 * Otherwise locking is needed, so there may be little value to inlining.
1844 *------------------------------------------------------------------------
1846 * IMPORTANT!!! The hot paths -- get/set value -- assume that callers
1847 * have requested the GPIO. That can include implicit requesting by
1848 * a direction setting call. Marking a gpio as requested locks its chip
1849 * in memory, guaranteeing that these table lookups need no more locking
1850 * and that gpiochip_remove() will fail.
1852 * REVISIT when debugging, consider adding some instrumentation to ensure
1853 * that the GPIO was actually requested.
1857 * __gpio_get_value() - return a gpio's value
1858 * @gpio: gpio whose value will be returned
1861 * This is used directly or indirectly to implement gpio_get_value().
1862 * It returns the zero or nonzero value provided by the associated
1863 * gpio_chip.get() method; or zero if no such method is provided.
1865 static int gpiod_get_value(const struct gpio_desc *desc)
1867 struct gpio_chip *chip;
1874 offset = gpio_chip_hwgpio(desc);
1875 /* Should be using gpio_get_value_cansleep() */
1876 WARN_ON(chip->can_sleep);
1877 value = chip->get ? chip->get(chip, offset) : 0;
1878 trace_gpio_value(desc_to_gpio(desc), 1, value);
1882 int __gpio_get_value(unsigned gpio)
1884 return gpiod_get_value(gpio_to_desc(gpio));
1886 EXPORT_SYMBOL_GPL(__gpio_get_value);
1889 * _gpio_set_open_drain_value() - Set the open drain gpio's value.
1890 * @gpio: Gpio whose state need to be set.
1892 * @value: Non-zero for setting it HIGH otherise it will set to LOW.
1894 static void _gpio_set_open_drain_value(struct gpio_desc *desc, int value)
1897 struct gpio_chip *chip = desc->chip;
1898 int offset = gpio_chip_hwgpio(desc);
1901 err = chip->direction_input(chip, offset);
1903 clear_bit(FLAG_IS_OUT, &desc->flags);
1905 err = chip->direction_output(chip, offset, 0);
1907 set_bit(FLAG_IS_OUT, &desc->flags);
1909 trace_gpio_direction(desc_to_gpio(desc), value, err);
1911 pr_err("%s: Error in set_value for open drain gpio%d err %d\n",
1912 __func__, desc_to_gpio(desc), err);
1916 * _gpio_set_open_source() - Set the open source gpio's value.
1917 * @gpio: Gpio whose state need to be set.
1919 * @value: Non-zero for setting it HIGH otherise it will set to LOW.
1921 static void _gpio_set_open_source_value(struct gpio_desc *desc, int value)
1924 struct gpio_chip *chip = desc->chip;
1925 int offset = gpio_chip_hwgpio(desc);
1928 err = chip->direction_output(chip, offset, 1);
1930 set_bit(FLAG_IS_OUT, &desc->flags);
1932 err = chip->direction_input(chip, offset);
1934 clear_bit(FLAG_IS_OUT, &desc->flags);
1936 trace_gpio_direction(desc_to_gpio(desc), !value, err);
1938 pr_err("%s: Error in set_value for open source gpio%d err %d\n",
1939 __func__, desc_to_gpio(desc), err);
1943 * __gpio_set_value() - assign a gpio's value
1944 * @gpio: gpio whose value will be assigned
1945 * @value: value to assign
1948 * This is used directly or indirectly to implement gpio_set_value().
1949 * It invokes the associated gpio_chip.set() method.
1951 static void gpiod_set_value(struct gpio_desc *desc, int value)
1953 struct gpio_chip *chip;
1958 /* Should be using gpio_set_value_cansleep() */
1959 WARN_ON(chip->can_sleep);
1960 trace_gpio_value(desc_to_gpio(desc), 0, value);
1961 if (test_bit(FLAG_OPEN_DRAIN, &desc->flags))
1962 _gpio_set_open_drain_value(desc, value);
1963 else if (test_bit(FLAG_OPEN_SOURCE, &desc->flags))
1964 _gpio_set_open_source_value(desc, value);
1966 chip->set(chip, gpio_chip_hwgpio(desc), value);
1969 void __gpio_set_value(unsigned gpio, int value)
1971 return gpiod_set_value(gpio_to_desc(gpio), value);
1973 EXPORT_SYMBOL_GPL(__gpio_set_value);
1976 * __gpio_cansleep() - report whether gpio value access will sleep
1977 * @gpio: gpio in question
1980 * This is used directly or indirectly to implement gpio_cansleep(). It
1981 * returns nonzero if access reading or writing the GPIO value can sleep.
1983 static int gpiod_cansleep(const struct gpio_desc *desc)
1987 /* only call this on GPIOs that are valid! */
1988 return desc->chip->can_sleep;
1991 int __gpio_cansleep(unsigned gpio)
1993 return gpiod_cansleep(gpio_to_desc(gpio));
1995 EXPORT_SYMBOL_GPL(__gpio_cansleep);
1998 * __gpio_to_irq() - return the IRQ corresponding to a GPIO
1999 * @gpio: gpio whose IRQ will be returned (already requested)
2002 * This is used directly or indirectly to implement gpio_to_irq().
2003 * It returns the number of the IRQ signaled by this (input) GPIO,
2004 * or a negative errno.
2006 static int gpiod_to_irq(const struct gpio_desc *desc)
2008 struct gpio_chip *chip;
2014 offset = gpio_chip_hwgpio(desc);
2015 return chip->to_irq ? chip->to_irq(chip, offset) : -ENXIO;
2018 int __gpio_to_irq(unsigned gpio)
2020 return gpiod_to_irq(gpio_to_desc(gpio));
2022 EXPORT_SYMBOL_GPL(__gpio_to_irq);
2025 /* There's no value in making it easy to inline GPIO calls that may sleep.
2026 * Common examples include ones connected to I2C or SPI chips.
2029 static int gpiod_get_value_cansleep(const struct gpio_desc *desc)
2031 struct gpio_chip *chip;
2035 might_sleep_if(extra_checks);
2039 offset = gpio_chip_hwgpio(desc);
2040 value = chip->get ? chip->get(chip, offset) : 0;
2041 trace_gpio_value(desc_to_gpio(desc), 1, value);
2045 int gpio_get_value_cansleep(unsigned gpio)
2047 return gpiod_get_value_cansleep(gpio_to_desc(gpio));
2049 EXPORT_SYMBOL_GPL(gpio_get_value_cansleep);
2051 static void gpiod_set_value_cansleep(struct gpio_desc *desc, int value)
2053 struct gpio_chip *chip;
2055 might_sleep_if(extra_checks);
2059 trace_gpio_value(desc_to_gpio(desc), 0, value);
2060 if (test_bit(FLAG_OPEN_DRAIN, &desc->flags))
2061 _gpio_set_open_drain_value(desc, value);
2062 else if (test_bit(FLAG_OPEN_SOURCE, &desc->flags))
2063 _gpio_set_open_source_value(desc, value);
2065 chip->set(chip, gpio_chip_hwgpio(desc), value);
2068 void gpio_set_value_cansleep(unsigned gpio, int value)
2070 return gpiod_set_value_cansleep(gpio_to_desc(gpio), value);
2072 EXPORT_SYMBOL_GPL(gpio_set_value_cansleep);
2074 #ifdef CONFIG_DEBUG_FS
2076 static void gpiolib_dbg_show(struct seq_file *s, struct gpio_chip *chip)
2079 unsigned gpio = chip->base;
2080 struct gpio_desc *gdesc = &chip->desc[0];
2083 for (i = 0; i < chip->ngpio; i++, gpio++, gdesc++) {
2084 if (!test_bit(FLAG_REQUESTED, &gdesc->flags))
2087 gpiod_get_direction(gdesc);
2088 is_out = test_bit(FLAG_IS_OUT, &gdesc->flags);
2089 seq_printf(s, " gpio-%-3d (%-20.20s) %s %s",
2091 is_out ? "out" : "in ",
2093 ? (chip->get(chip, i) ? "hi" : "lo")
2095 seq_printf(s, "\n");
2099 static void *gpiolib_seq_start(struct seq_file *s, loff_t *pos)
2101 unsigned long flags;
2102 struct gpio_chip *chip = NULL;
2103 loff_t index = *pos;
2107 spin_lock_irqsave(&gpio_lock, flags);
2108 list_for_each_entry(chip, &gpio_chips, list)
2110 spin_unlock_irqrestore(&gpio_lock, flags);
2113 spin_unlock_irqrestore(&gpio_lock, flags);
2118 static void *gpiolib_seq_next(struct seq_file *s, void *v, loff_t *pos)
2120 unsigned long flags;
2121 struct gpio_chip *chip = v;
2124 spin_lock_irqsave(&gpio_lock, flags);
2125 if (list_is_last(&chip->list, &gpio_chips))
2128 ret = list_entry(chip->list.next, struct gpio_chip, list);
2129 spin_unlock_irqrestore(&gpio_lock, flags);
2137 static void gpiolib_seq_stop(struct seq_file *s, void *v)
2141 static int gpiolib_seq_show(struct seq_file *s, void *v)
2143 struct gpio_chip *chip = v;
2146 seq_printf(s, "%sGPIOs %d-%d", (char *)s->private,
2147 chip->base, chip->base + chip->ngpio - 1);
2150 seq_printf(s, ", %s/%s", dev->bus ? dev->bus->name : "no-bus",
2153 seq_printf(s, ", %s", chip->label);
2154 if (chip->can_sleep)
2155 seq_printf(s, ", can sleep");
2156 seq_printf(s, ":\n");
2159 chip->dbg_show(s, chip);
2161 gpiolib_dbg_show(s, chip);
2166 static const struct seq_operations gpiolib_seq_ops = {
2167 .start = gpiolib_seq_start,
2168 .next = gpiolib_seq_next,
2169 .stop = gpiolib_seq_stop,
2170 .show = gpiolib_seq_show,
2173 static int gpiolib_open(struct inode *inode, struct file *file)
2175 return seq_open(file, &gpiolib_seq_ops);
2178 static const struct file_operations gpiolib_operations = {
2179 .owner = THIS_MODULE,
2180 .open = gpiolib_open,
2182 .llseek = seq_lseek,
2183 .release = seq_release,
2186 static int __init gpiolib_debugfs_init(void)
2188 /* /sys/kernel/debug/gpio */
2189 (void) debugfs_create_file("gpio", S_IFREG | S_IRUGO,
2190 NULL, NULL, &gpiolib_operations);
2193 subsys_initcall(gpiolib_debugfs_init);
2195 #endif /* DEBUG_FS */