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
)
757 const char *ioname
= NULL
;
761 /* can't export until sysfs is available ... */
763 pr_debug("%s: called too early!\n", __func__
);
768 pr_debug("%s: invalid gpio descriptor\n", __func__
);
772 mutex_lock(&sysfs_lock
);
774 spin_lock_irqsave(&gpio_lock
, flags
);
775 if (!test_bit(FLAG_REQUESTED
, &desc
->flags
) ||
776 test_bit(FLAG_EXPORT
, &desc
->flags
)) {
777 spin_unlock_irqrestore(&gpio_lock
, flags
);
778 pr_debug("%s: gpio %d unavailable (requested=%d, exported=%d)\n",
779 __func__
, desc_to_gpio(desc
),
780 test_bit(FLAG_REQUESTED
, &desc
->flags
),
781 test_bit(FLAG_EXPORT
, &desc
->flags
));
786 if (!desc
->chip
->direction_input
|| !desc
->chip
->direction_output
)
787 direction_may_change
= false;
788 spin_unlock_irqrestore(&gpio_lock
, flags
);
790 offset
= gpio_chip_hwgpio(desc
);
791 if (desc
->chip
->names
&& desc
->chip
->names
[offset
])
792 ioname
= desc
->chip
->names
[offset
];
794 dev
= device_create(&gpio_class
, desc
->chip
->dev
, MKDEV(0, 0),
795 desc
, ioname
? ioname
: "gpio%u",
798 status
= PTR_ERR(dev
);
802 status
= sysfs_create_group(&dev
->kobj
, &gpio_attr_group
);
804 goto fail_unregister_device
;
806 if (direction_may_change
) {
807 status
= device_create_file(dev
, &dev_attr_direction
);
809 goto fail_remove_attr_group
;
812 if (gpiod_to_irq(desc
) >= 0 && (direction_may_change
||
813 !test_bit(FLAG_IS_OUT
, &desc
->flags
))) {
814 status
= device_create_file(dev
, &dev_attr_edge
);
816 goto fail_remove_attr_direction
;
819 set_bit(FLAG_EXPORT
, &desc
->flags
);
820 mutex_unlock(&sysfs_lock
);
823 fail_remove_attr_direction
:
824 device_remove_file(dev
, &dev_attr_direction
);
825 fail_remove_attr_group
:
826 sysfs_remove_group(&dev
->kobj
, &gpio_attr_group
);
827 fail_unregister_device
:
828 device_unregister(dev
);
830 mutex_unlock(&sysfs_lock
);
831 pr_debug("%s: gpio%d status %d\n", __func__
, desc_to_gpio(desc
),
836 int gpio_export(unsigned gpio
, bool direction_may_change
)
838 return gpiod_export(gpio_to_desc(gpio
), direction_may_change
);
840 EXPORT_SYMBOL_GPL(gpio_export
);
842 static int match_export(struct device
*dev
, const void *data
)
844 return dev_get_drvdata(dev
) == data
;
848 * gpio_export_link - create a sysfs link to an exported GPIO node
849 * @dev: device under which to create symlink
850 * @name: name of the symlink
851 * @gpio: gpio to create symlink to, already exported
853 * Set up a symlink from /sys/.../dev/name to /sys/class/gpio/gpioN
854 * node. Caller is responsible for unlinking.
856 * Returns zero on success, else an error.
858 static int gpiod_export_link(struct device
*dev
, const char *name
,
859 struct gpio_desc
*desc
)
861 int status
= -EINVAL
;
864 pr_warn("%s: invalid GPIO\n", __func__
);
868 mutex_lock(&sysfs_lock
);
870 if (test_bit(FLAG_EXPORT
, &desc
->flags
)) {
873 tdev
= class_find_device(&gpio_class
, NULL
, desc
, match_export
);
875 status
= sysfs_create_link(&dev
->kobj
, &tdev
->kobj
,
882 mutex_unlock(&sysfs_lock
);
885 pr_debug("%s: gpio%d status %d\n", __func__
, desc_to_gpio(desc
),
891 int gpio_export_link(struct device
*dev
, const char *name
, unsigned gpio
)
893 return gpiod_export_link(dev
, name
, gpio_to_desc(gpio
));
895 EXPORT_SYMBOL_GPL(gpio_export_link
);
898 * gpio_sysfs_set_active_low - set the polarity of gpio sysfs value
899 * @gpio: gpio to change
900 * @value: non-zero to use active low, i.e. inverted values
902 * Set the polarity of /sys/class/gpio/gpioN/value sysfs attribute.
903 * The GPIO does not have to be exported yet. If poll(2) support has
904 * been enabled for either rising or falling edge, it will be
905 * reconfigured to follow the new polarity.
907 * Returns zero on success, else an error.
909 static int gpiod_sysfs_set_active_low(struct gpio_desc
*desc
, int value
)
911 struct device
*dev
= NULL
;
912 int status
= -EINVAL
;
915 pr_warn("%s: invalid GPIO\n", __func__
);
919 mutex_lock(&sysfs_lock
);
921 if (test_bit(FLAG_EXPORT
, &desc
->flags
)) {
922 dev
= class_find_device(&gpio_class
, NULL
, desc
, match_export
);
929 status
= sysfs_set_active_low(desc
, dev
, value
);
932 mutex_unlock(&sysfs_lock
);
935 pr_debug("%s: gpio%d status %d\n", __func__
, desc_to_gpio(desc
),
941 int gpio_sysfs_set_active_low(unsigned gpio
, int value
)
943 return gpiod_sysfs_set_active_low(gpio_to_desc(gpio
), value
);
945 EXPORT_SYMBOL_GPL(gpio_sysfs_set_active_low
);
948 * gpio_unexport - reverse effect of gpio_export()
949 * @gpio: gpio to make unavailable
951 * This is implicit on gpio_free().
953 static void gpiod_unexport(struct gpio_desc
*desc
)
956 struct device
*dev
= NULL
;
959 pr_warn("%s: invalid GPIO\n", __func__
);
963 mutex_lock(&sysfs_lock
);
965 if (test_bit(FLAG_EXPORT
, &desc
->flags
)) {
967 dev
= class_find_device(&gpio_class
, NULL
, desc
, match_export
);
969 gpio_setup_irq(desc
, dev
, 0);
970 clear_bit(FLAG_EXPORT
, &desc
->flags
);
975 mutex_unlock(&sysfs_lock
);
978 device_remove_file(dev
, &dev_attr_edge
);
979 device_remove_file(dev
, &dev_attr_direction
);
980 sysfs_remove_group(&dev
->kobj
, &gpio_attr_group
);
981 device_unregister(dev
);
986 pr_debug("%s: gpio%d status %d\n", __func__
, desc_to_gpio(desc
),
990 void gpio_unexport(unsigned gpio
)
992 gpiod_unexport(gpio_to_desc(gpio
));
994 EXPORT_SYMBOL_GPL(gpio_unexport
);
996 static int gpiochip_export(struct gpio_chip
*chip
)
1001 /* Many systems register gpio chips for SOC support very early,
1002 * before driver model support is available. In those cases we
1003 * export this later, in gpiolib_sysfs_init() ... here we just
1004 * verify that _some_ field of gpio_class got initialized.
1009 /* use chip->base for the ID; it's already known to be unique */
1010 mutex_lock(&sysfs_lock
);
1011 dev
= device_create(&gpio_class
, chip
->dev
, MKDEV(0, 0), chip
,
1012 "gpiochip%d", chip
->base
);
1014 status
= sysfs_create_group(&dev
->kobj
,
1015 &gpiochip_attr_group
);
1017 status
= PTR_ERR(dev
);
1018 chip
->exported
= (status
== 0);
1019 mutex_unlock(&sysfs_lock
);
1022 unsigned long flags
;
1025 spin_lock_irqsave(&gpio_lock
, flags
);
1027 while (gpio
< chip
->ngpio
)
1028 chip
->desc
[gpio
++].chip
= NULL
;
1029 spin_unlock_irqrestore(&gpio_lock
, flags
);
1031 pr_debug("%s: chip %s status %d\n", __func__
,
1032 chip
->label
, status
);
1038 static void gpiochip_unexport(struct gpio_chip
*chip
)
1043 mutex_lock(&sysfs_lock
);
1044 dev
= class_find_device(&gpio_class
, NULL
, chip
, match_export
);
1046 sysfs_remove_group(&dev
->kobj
, &gpiochip_attr_group
);
1048 device_unregister(dev
);
1053 mutex_unlock(&sysfs_lock
);
1056 pr_debug("%s: chip %s status %d\n", __func__
,
1057 chip
->label
, status
);
1060 static int __init
gpiolib_sysfs_init(void)
1063 unsigned long flags
;
1064 struct gpio_chip
*chip
;
1066 status
= class_register(&gpio_class
);
1070 /* Scan and register the gpio_chips which registered very
1071 * early (e.g. before the class_register above was called).
1073 * We run before arch_initcall() so chip->dev nodes can have
1074 * registered, and so arch_initcall() can always gpio_export().
1076 spin_lock_irqsave(&gpio_lock
, flags
);
1077 list_for_each_entry(chip
, &gpio_chips
, list
) {
1078 if (!chip
|| chip
->exported
)
1081 spin_unlock_irqrestore(&gpio_lock
, flags
);
1082 status
= gpiochip_export(chip
);
1083 spin_lock_irqsave(&gpio_lock
, flags
);
1085 spin_unlock_irqrestore(&gpio_lock
, flags
);
1090 postcore_initcall(gpiolib_sysfs_init
);
1093 static inline int gpiochip_export(struct gpio_chip
*chip
)
1098 static inline void gpiochip_unexport(struct gpio_chip
*chip
)
1102 static inline int gpiod_export(struct gpio_desc
*desc
,
1103 bool direction_may_change
)
1108 static inline int gpiod_export_link(struct device
*dev
, const char *name
,
1109 struct gpio_desc
*desc
)
1114 static inline int gpiod_sysfs_set_active_low(struct gpio_desc
*desc
, int value
)
1119 static inline void gpiod_unexport(struct gpio_desc
*desc
)
1123 #endif /* CONFIG_GPIO_SYSFS */
1126 * Add a new chip to the global chips list, keeping the list of chips sorted
1129 * Return -EBUSY if the new chip overlaps with some other chip's integer
1132 static int gpiochip_add_to_list(struct gpio_chip
*chip
)
1134 struct list_head
*pos
= &gpio_chips
;
1135 struct gpio_chip
*_chip
;
1138 /* find where to insert our chip */
1139 list_for_each(pos
, &gpio_chips
) {
1140 _chip
= list_entry(pos
, struct gpio_chip
, list
);
1141 /* shall we insert before _chip? */
1142 if (_chip
->base
>= chip
->base
+ chip
->ngpio
)
1146 /* are we stepping on the chip right before? */
1147 if (pos
!= &gpio_chips
&& pos
->prev
!= &gpio_chips
) {
1148 _chip
= list_entry(pos
->prev
, struct gpio_chip
, list
);
1149 if (_chip
->base
+ _chip
->ngpio
> chip
->base
) {
1151 "GPIO integer space overlap, cannot add chip\n");
1157 list_add_tail(&chip
->list
, pos
);
1163 * gpiochip_add() - register a gpio_chip
1164 * @chip: the chip to register, with chip->base initialized
1165 * Context: potentially before irqs or kmalloc will work
1167 * Returns a negative errno if the chip can't be registered, such as
1168 * because the chip->base is invalid or already associated with a
1169 * different chip. Otherwise it returns zero as a success code.
1171 * When gpiochip_add() is called very early during boot, so that GPIOs
1172 * can be freely used, the chip->dev device must be registered before
1173 * the gpio framework's arch_initcall(). Otherwise sysfs initialization
1174 * for GPIOs will fail rudely.
1176 * If chip->base is negative, this requests dynamic assignment of
1177 * a range of valid GPIOs.
1179 int gpiochip_add(struct gpio_chip
*chip
)
1181 unsigned long flags
;
1184 int base
= chip
->base
;
1186 if ((!gpio_is_valid(base
) || !gpio_is_valid(base
+ chip
->ngpio
- 1))
1192 spin_lock_irqsave(&gpio_lock
, flags
);
1195 base
= gpiochip_find_base(chip
->ngpio
);
1203 status
= gpiochip_add_to_list(chip
);
1206 chip
->desc
= &gpio_desc
[chip
->base
];
1208 for (id
= 0; id
< chip
->ngpio
; id
++) {
1209 struct gpio_desc
*desc
= &chip
->desc
[id
];
1212 /* REVISIT: most hardware initializes GPIOs as
1213 * inputs (often with pullups enabled) so power
1214 * usage is minimized. Linux code should set the
1215 * gpio direction first thing; but until it does,
1216 * and in case chip->get_direction is not set,
1217 * we may expose the wrong direction in sysfs.
1219 desc
->flags
= !chip
->direction_input
1220 ? (1 << FLAG_IS_OUT
)
1225 spin_unlock_irqrestore(&gpio_lock
, flags
);
1227 #ifdef CONFIG_PINCTRL
1228 INIT_LIST_HEAD(&chip
->pin_ranges
);
1231 of_gpiochip_add(chip
);
1236 status
= gpiochip_export(chip
);
1240 pr_debug("gpiochip_add: registered GPIOs %d to %d on device: %s\n",
1241 chip
->base
, chip
->base
+ chip
->ngpio
- 1,
1242 chip
->label
? : "generic");
1247 spin_unlock_irqrestore(&gpio_lock
, flags
);
1249 /* failures here can mean systems won't boot... */
1250 pr_err("gpiochip_add: gpios %d..%d (%s) failed to register\n",
1251 chip
->base
, chip
->base
+ chip
->ngpio
- 1,
1252 chip
->label
? : "generic");
1255 EXPORT_SYMBOL_GPL(gpiochip_add
);
1258 * gpiochip_remove() - unregister a gpio_chip
1259 * @chip: the chip to unregister
1261 * A gpio_chip with any GPIOs still requested may not be removed.
1263 int gpiochip_remove(struct gpio_chip
*chip
)
1265 unsigned long flags
;
1269 spin_lock_irqsave(&gpio_lock
, flags
);
1271 gpiochip_remove_pin_ranges(chip
);
1272 of_gpiochip_remove(chip
);
1274 for (id
= 0; id
< chip
->ngpio
; id
++) {
1275 if (test_bit(FLAG_REQUESTED
, &chip
->desc
[id
].flags
)) {
1281 for (id
= 0; id
< chip
->ngpio
; id
++)
1282 chip
->desc
[id
].chip
= NULL
;
1284 list_del(&chip
->list
);
1287 spin_unlock_irqrestore(&gpio_lock
, flags
);
1290 gpiochip_unexport(chip
);
1294 EXPORT_SYMBOL_GPL(gpiochip_remove
);
1297 * gpiochip_find() - iterator for locating a specific gpio_chip
1298 * @data: data to pass to match function
1299 * @callback: Callback function to check gpio_chip
1301 * Similar to bus_find_device. It returns a reference to a gpio_chip as
1302 * determined by a user supplied @match callback. The callback should return
1303 * 0 if the device doesn't match and non-zero if it does. If the callback is
1304 * non-zero, this function will return to the caller and not iterate over any
1307 struct gpio_chip
*gpiochip_find(void *data
,
1308 int (*match
)(struct gpio_chip
*chip
,
1311 struct gpio_chip
*chip
;
1312 unsigned long flags
;
1314 spin_lock_irqsave(&gpio_lock
, flags
);
1315 list_for_each_entry(chip
, &gpio_chips
, list
)
1316 if (match(chip
, data
))
1320 if (&chip
->list
== &gpio_chips
)
1322 spin_unlock_irqrestore(&gpio_lock
, flags
);
1326 EXPORT_SYMBOL_GPL(gpiochip_find
);
1328 #ifdef CONFIG_PINCTRL
1331 * gpiochip_add_pin_range() - add a range for GPIO <-> pin mapping
1332 * @chip: the gpiochip to add the range for
1333 * @pinctrl_name: the dev_name() of the pin controller to map to
1334 * @gpio_offset: the start offset in the current gpio_chip number space
1335 * @pin_offset: the start offset in the pin controller number space
1336 * @npins: the number of pins from the offset of each pin space (GPIO and
1337 * pin controller) to accumulate in this range
1339 int gpiochip_add_pin_range(struct gpio_chip
*chip
, const char *pinctl_name
,
1340 unsigned int gpio_offset
, unsigned int pin_offset
,
1343 struct gpio_pin_range
*pin_range
;
1346 pin_range
= kzalloc(sizeof(*pin_range
), GFP_KERNEL
);
1348 pr_err("%s: GPIO chip: failed to allocate pin ranges\n",
1353 /* Use local offset as range ID */
1354 pin_range
->range
.id
= gpio_offset
;
1355 pin_range
->range
.gc
= chip
;
1356 pin_range
->range
.name
= chip
->label
;
1357 pin_range
->range
.base
= chip
->base
+ gpio_offset
;
1358 pin_range
->range
.pin_base
= pin_offset
;
1359 pin_range
->range
.npins
= npins
;
1360 pin_range
->pctldev
= pinctrl_find_and_add_gpio_range(pinctl_name
,
1362 if (IS_ERR(pin_range
->pctldev
)) {
1363 ret
= PTR_ERR(pin_range
->pctldev
);
1364 pr_err("%s: GPIO chip: could not create pin range\n",
1369 pr_debug("GPIO chip %s: created GPIO range %d->%d ==> %s PIN %d->%d\n",
1370 chip
->label
, gpio_offset
, gpio_offset
+ npins
- 1,
1372 pin_offset
, pin_offset
+ npins
- 1);
1374 list_add_tail(&pin_range
->node
, &chip
->pin_ranges
);
1378 EXPORT_SYMBOL_GPL(gpiochip_add_pin_range
);
1381 * gpiochip_remove_pin_ranges() - remove all the GPIO <-> pin mappings
1382 * @chip: the chip to remove all the mappings for
1384 void gpiochip_remove_pin_ranges(struct gpio_chip
*chip
)
1386 struct gpio_pin_range
*pin_range
, *tmp
;
1388 list_for_each_entry_safe(pin_range
, tmp
, &chip
->pin_ranges
, node
) {
1389 list_del(&pin_range
->node
);
1390 pinctrl_remove_gpio_range(pin_range
->pctldev
,
1395 EXPORT_SYMBOL_GPL(gpiochip_remove_pin_ranges
);
1397 #endif /* CONFIG_PINCTRL */
1399 /* These "optional" allocation calls help prevent drivers from stomping
1400 * on each other, and help provide better diagnostics in debugfs.
1401 * They're called even less than the "set direction" calls.
1403 static int gpiod_request(struct gpio_desc
*desc
, const char *label
)
1405 struct gpio_chip
*chip
;
1406 int status
= -EPROBE_DEFER
;
1407 unsigned long flags
;
1410 pr_warn("%s: invalid GPIO\n", __func__
);
1414 spin_lock_irqsave(&gpio_lock
, flags
);
1420 if (!try_module_get(chip
->owner
))
1423 /* NOTE: gpio_request() can be called in early boot,
1424 * before IRQs are enabled, for non-sleeping (SOC) GPIOs.
1427 if (test_and_set_bit(FLAG_REQUESTED
, &desc
->flags
) == 0) {
1428 desc_set_label(desc
, label
? : "?");
1432 module_put(chip
->owner
);
1436 if (chip
->request
) {
1437 /* chip->request may sleep */
1438 spin_unlock_irqrestore(&gpio_lock
, flags
);
1439 status
= chip
->request(chip
, gpio_chip_hwgpio(desc
));
1440 spin_lock_irqsave(&gpio_lock
, flags
);
1443 desc_set_label(desc
, NULL
);
1444 module_put(chip
->owner
);
1445 clear_bit(FLAG_REQUESTED
, &desc
->flags
);
1449 if (chip
->get_direction
) {
1450 /* chip->get_direction may sleep */
1451 spin_unlock_irqrestore(&gpio_lock
, flags
);
1452 gpiod_get_direction(desc
);
1453 spin_lock_irqsave(&gpio_lock
, flags
);
1457 pr_debug("_gpio_request: gpio-%d (%s) status %d\n",
1458 desc_to_gpio(desc
), label
? : "?", status
);
1459 spin_unlock_irqrestore(&gpio_lock
, flags
);
1463 int gpio_request(unsigned gpio
, const char *label
)
1465 return gpiod_request(gpio_to_desc(gpio
), label
);
1467 EXPORT_SYMBOL_GPL(gpio_request
);
1469 static void gpiod_free(struct gpio_desc
*desc
)
1471 unsigned long flags
;
1472 struct gpio_chip
*chip
;
1477 WARN_ON(extra_checks
);
1481 gpiod_unexport(desc
);
1483 spin_lock_irqsave(&gpio_lock
, flags
);
1486 if (chip
&& test_bit(FLAG_REQUESTED
, &desc
->flags
)) {
1488 spin_unlock_irqrestore(&gpio_lock
, flags
);
1489 might_sleep_if(chip
->can_sleep
);
1490 chip
->free(chip
, gpio_chip_hwgpio(desc
));
1491 spin_lock_irqsave(&gpio_lock
, flags
);
1493 desc_set_label(desc
, NULL
);
1494 module_put(desc
->chip
->owner
);
1495 clear_bit(FLAG_ACTIVE_LOW
, &desc
->flags
);
1496 clear_bit(FLAG_REQUESTED
, &desc
->flags
);
1497 clear_bit(FLAG_OPEN_DRAIN
, &desc
->flags
);
1498 clear_bit(FLAG_OPEN_SOURCE
, &desc
->flags
);
1500 WARN_ON(extra_checks
);
1502 spin_unlock_irqrestore(&gpio_lock
, flags
);
1505 void gpio_free(unsigned gpio
)
1507 gpiod_free(gpio_to_desc(gpio
));
1509 EXPORT_SYMBOL_GPL(gpio_free
);
1512 * gpio_request_one - request a single GPIO with initial configuration
1513 * @gpio: the GPIO number
1514 * @flags: GPIO configuration as specified by GPIOF_*
1515 * @label: a literal description string of this GPIO
1517 int gpio_request_one(unsigned gpio
, unsigned long flags
, const char *label
)
1519 struct gpio_desc
*desc
;
1522 desc
= gpio_to_desc(gpio
);
1524 err
= gpiod_request(desc
, label
);
1528 if (flags
& GPIOF_OPEN_DRAIN
)
1529 set_bit(FLAG_OPEN_DRAIN
, &desc
->flags
);
1531 if (flags
& GPIOF_OPEN_SOURCE
)
1532 set_bit(FLAG_OPEN_SOURCE
, &desc
->flags
);
1534 if (flags
& GPIOF_DIR_IN
)
1535 err
= gpiod_direction_input(desc
);
1537 err
= gpiod_direction_output(desc
,
1538 (flags
& GPIOF_INIT_HIGH
) ? 1 : 0);
1543 if (flags
& GPIOF_EXPORT
) {
1544 err
= gpiod_export(desc
, flags
& GPIOF_EXPORT_CHANGEABLE
);
1555 EXPORT_SYMBOL_GPL(gpio_request_one
);
1558 * gpio_request_array - request multiple GPIOs in a single call
1559 * @array: array of the 'struct gpio'
1560 * @num: how many GPIOs in the array
1562 int gpio_request_array(const struct gpio
*array
, size_t num
)
1566 for (i
= 0; i
< num
; i
++, array
++) {
1567 err
= gpio_request_one(array
->gpio
, array
->flags
, array
->label
);
1575 gpio_free((--array
)->gpio
);
1578 EXPORT_SYMBOL_GPL(gpio_request_array
);
1581 * gpio_free_array - release multiple GPIOs in a single call
1582 * @array: array of the 'struct gpio'
1583 * @num: how many GPIOs in the array
1585 void gpio_free_array(const struct gpio
*array
, size_t num
)
1588 gpio_free((array
++)->gpio
);
1590 EXPORT_SYMBOL_GPL(gpio_free_array
);
1593 * gpiochip_is_requested - return string iff signal was requested
1594 * @chip: controller managing the signal
1595 * @offset: of signal within controller's 0..(ngpio - 1) range
1597 * Returns NULL if the GPIO is not currently requested, else a string.
1598 * If debugfs support is enabled, the string returned is the label passed
1599 * to gpio_request(); otherwise it is a meaningless constant.
1601 * This function is for use by GPIO controller drivers. The label can
1602 * help with diagnostics, and knowing that the signal is used as a GPIO
1603 * can help avoid accidentally multiplexing it to another controller.
1605 const char *gpiochip_is_requested(struct gpio_chip
*chip
, unsigned offset
)
1607 struct gpio_desc
*desc
;
1609 if (!GPIO_OFFSET_VALID(chip
, offset
))
1612 desc
= &chip
->desc
[offset
];
1614 if (test_bit(FLAG_REQUESTED
, &desc
->flags
) == 0)
1616 #ifdef CONFIG_DEBUG_FS
1622 EXPORT_SYMBOL_GPL(gpiochip_is_requested
);
1625 /* Drivers MUST set GPIO direction before making get/set calls. In
1626 * some cases this is done in early boot, before IRQs are enabled.
1628 * As a rule these aren't called more than once (except for drivers
1629 * using the open-drain emulation idiom) so these are natural places
1630 * to accumulate extra debugging checks. Note that we can't (yet)
1631 * rely on gpio_request() having been called beforehand.
1634 static int gpiod_direction_input(struct gpio_desc
*desc
)
1636 unsigned long flags
;
1637 struct gpio_chip
*chip
;
1638 int status
= -EINVAL
;
1642 pr_warn("%s: invalid GPIO\n", __func__
);
1646 spin_lock_irqsave(&gpio_lock
, flags
);
1649 if (!chip
|| !chip
->get
|| !chip
->direction_input
)
1651 status
= gpio_ensure_requested(desc
);
1655 /* now we know the gpio is valid and chip won't vanish */
1657 spin_unlock_irqrestore(&gpio_lock
, flags
);
1659 might_sleep_if(chip
->can_sleep
);
1661 offset
= gpio_chip_hwgpio(desc
);
1663 status
= chip
->request(chip
, offset
);
1665 pr_debug("GPIO-%d: chip request fail, %d\n",
1666 desc_to_gpio(desc
), status
);
1667 /* and it's not available to anyone else ...
1668 * gpio_request() is the fully clean solution.
1674 status
= chip
->direction_input(chip
, offset
);
1676 clear_bit(FLAG_IS_OUT
, &desc
->flags
);
1678 trace_gpio_direction(desc_to_gpio(desc
), 1, status
);
1682 spin_unlock_irqrestore(&gpio_lock
, flags
);
1684 pr_debug("%s: gpio-%d status %d\n", __func__
,
1685 desc_to_gpio(desc
), status
);
1689 int gpio_direction_input(unsigned gpio
)
1691 return gpiod_direction_input(gpio_to_desc(gpio
));
1693 EXPORT_SYMBOL_GPL(gpio_direction_input
);
1695 static int gpiod_direction_output(struct gpio_desc
*desc
, int value
)
1697 unsigned long flags
;
1698 struct gpio_chip
*chip
;
1699 int status
= -EINVAL
;
1703 pr_warn("%s: invalid GPIO\n", __func__
);
1707 /* Open drain pin should not be driven to 1 */
1708 if (value
&& test_bit(FLAG_OPEN_DRAIN
, &desc
->flags
))
1709 return gpiod_direction_input(desc
);
1711 /* Open source pin should not be driven to 0 */
1712 if (!value
&& test_bit(FLAG_OPEN_SOURCE
, &desc
->flags
))
1713 return gpiod_direction_input(desc
);
1715 spin_lock_irqsave(&gpio_lock
, flags
);
1718 if (!chip
|| !chip
->set
|| !chip
->direction_output
)
1720 status
= gpio_ensure_requested(desc
);
1724 /* now we know the gpio is valid and chip won't vanish */
1726 spin_unlock_irqrestore(&gpio_lock
, flags
);
1728 might_sleep_if(chip
->can_sleep
);
1730 offset
= gpio_chip_hwgpio(desc
);
1732 status
= chip
->request(chip
, offset
);
1734 pr_debug("GPIO-%d: chip request fail, %d\n",
1735 desc_to_gpio(desc
), status
);
1736 /* and it's not available to anyone else ...
1737 * gpio_request() is the fully clean solution.
1743 status
= chip
->direction_output(chip
, offset
, value
);
1745 set_bit(FLAG_IS_OUT
, &desc
->flags
);
1746 trace_gpio_value(desc_to_gpio(desc
), 0, value
);
1747 trace_gpio_direction(desc_to_gpio(desc
), 0, status
);
1751 spin_unlock_irqrestore(&gpio_lock
, flags
);
1753 pr_debug("%s: gpio-%d status %d\n", __func__
,
1754 desc_to_gpio(desc
), status
);
1758 int gpio_direction_output(unsigned gpio
, int value
)
1760 return gpiod_direction_output(gpio_to_desc(gpio
), value
);
1762 EXPORT_SYMBOL_GPL(gpio_direction_output
);
1765 * gpio_set_debounce - sets @debounce time for a @gpio
1766 * @gpio: the gpio to set debounce time
1767 * @debounce: debounce time is microseconds
1769 static int gpiod_set_debounce(struct gpio_desc
*desc
, unsigned debounce
)
1771 unsigned long flags
;
1772 struct gpio_chip
*chip
;
1773 int status
= -EINVAL
;
1777 pr_warn("%s: invalid GPIO\n", __func__
);
1781 spin_lock_irqsave(&gpio_lock
, flags
);
1784 if (!chip
|| !chip
->set
|| !chip
->set_debounce
)
1787 status
= gpio_ensure_requested(desc
);
1791 /* now we know the gpio is valid and chip won't vanish */
1793 spin_unlock_irqrestore(&gpio_lock
, flags
);
1795 might_sleep_if(chip
->can_sleep
);
1797 offset
= gpio_chip_hwgpio(desc
);
1798 return chip
->set_debounce(chip
, offset
, debounce
);
1801 spin_unlock_irqrestore(&gpio_lock
, flags
);
1803 pr_debug("%s: gpio-%d status %d\n", __func__
,
1804 desc_to_gpio(desc
), status
);
1809 int gpio_set_debounce(unsigned gpio
, unsigned debounce
)
1811 return gpiod_set_debounce(gpio_to_desc(gpio
), debounce
);
1813 EXPORT_SYMBOL_GPL(gpio_set_debounce
);
1815 /* I/O calls are only valid after configuration completed; the relevant
1816 * "is this a valid GPIO" error checks should already have been done.
1818 * "Get" operations are often inlinable as reading a pin value register,
1819 * and masking the relevant bit in that register.
1821 * When "set" operations are inlinable, they involve writing that mask to
1822 * one register to set a low value, or a different register to set it high.
1823 * Otherwise locking is needed, so there may be little value to inlining.
1825 *------------------------------------------------------------------------
1827 * IMPORTANT!!! The hot paths -- get/set value -- assume that callers
1828 * have requested the GPIO. That can include implicit requesting by
1829 * a direction setting call. Marking a gpio as requested locks its chip
1830 * in memory, guaranteeing that these table lookups need no more locking
1831 * and that gpiochip_remove() will fail.
1833 * REVISIT when debugging, consider adding some instrumentation to ensure
1834 * that the GPIO was actually requested.
1838 * __gpio_get_value() - return a gpio's value
1839 * @gpio: gpio whose value will be returned
1842 * This is used directly or indirectly to implement gpio_get_value().
1843 * It returns the zero or nonzero value provided by the associated
1844 * gpio_chip.get() method; or zero if no such method is provided.
1846 static int gpiod_get_value(const struct gpio_desc
*desc
)
1848 struct gpio_chip
*chip
;
1855 offset
= gpio_chip_hwgpio(desc
);
1856 /* Should be using gpio_get_value_cansleep() */
1857 WARN_ON(chip
->can_sleep
);
1858 value
= chip
->get
? chip
->get(chip
, offset
) : 0;
1859 trace_gpio_value(desc_to_gpio(desc
), 1, value
);
1863 int __gpio_get_value(unsigned gpio
)
1865 return gpiod_get_value(gpio_to_desc(gpio
));
1867 EXPORT_SYMBOL_GPL(__gpio_get_value
);
1870 * _gpio_set_open_drain_value() - Set the open drain gpio's value.
1871 * @gpio: Gpio whose state need to be set.
1873 * @value: Non-zero for setting it HIGH otherise it will set to LOW.
1875 static void _gpio_set_open_drain_value(struct gpio_desc
*desc
, int value
)
1878 struct gpio_chip
*chip
= desc
->chip
;
1879 int offset
= gpio_chip_hwgpio(desc
);
1882 err
= chip
->direction_input(chip
, offset
);
1884 clear_bit(FLAG_IS_OUT
, &desc
->flags
);
1886 err
= chip
->direction_output(chip
, offset
, 0);
1888 set_bit(FLAG_IS_OUT
, &desc
->flags
);
1890 trace_gpio_direction(desc_to_gpio(desc
), value
, err
);
1892 pr_err("%s: Error in set_value for open drain gpio%d err %d\n",
1893 __func__
, desc_to_gpio(desc
), err
);
1897 * _gpio_set_open_source() - Set the open source gpio's value.
1898 * @gpio: Gpio whose state need to be set.
1900 * @value: Non-zero for setting it HIGH otherise it will set to LOW.
1902 static void _gpio_set_open_source_value(struct gpio_desc
*desc
, int value
)
1905 struct gpio_chip
*chip
= desc
->chip
;
1906 int offset
= gpio_chip_hwgpio(desc
);
1909 err
= chip
->direction_output(chip
, offset
, 1);
1911 set_bit(FLAG_IS_OUT
, &desc
->flags
);
1913 err
= chip
->direction_input(chip
, offset
);
1915 clear_bit(FLAG_IS_OUT
, &desc
->flags
);
1917 trace_gpio_direction(desc_to_gpio(desc
), !value
, err
);
1919 pr_err("%s: Error in set_value for open source gpio%d err %d\n",
1920 __func__
, desc_to_gpio(desc
), err
);
1924 * __gpio_set_value() - assign a gpio's value
1925 * @gpio: gpio whose value will be assigned
1926 * @value: value to assign
1929 * This is used directly or indirectly to implement gpio_set_value().
1930 * It invokes the associated gpio_chip.set() method.
1932 static void gpiod_set_value(struct gpio_desc
*desc
, int value
)
1934 struct gpio_chip
*chip
;
1939 /* Should be using gpio_set_value_cansleep() */
1940 WARN_ON(chip
->can_sleep
);
1941 trace_gpio_value(desc_to_gpio(desc
), 0, value
);
1942 if (test_bit(FLAG_OPEN_DRAIN
, &desc
->flags
))
1943 _gpio_set_open_drain_value(desc
, value
);
1944 else if (test_bit(FLAG_OPEN_SOURCE
, &desc
->flags
))
1945 _gpio_set_open_source_value(desc
, value
);
1947 chip
->set(chip
, gpio_chip_hwgpio(desc
), value
);
1950 void __gpio_set_value(unsigned gpio
, int value
)
1952 return gpiod_set_value(gpio_to_desc(gpio
), value
);
1954 EXPORT_SYMBOL_GPL(__gpio_set_value
);
1957 * __gpio_cansleep() - report whether gpio value access will sleep
1958 * @gpio: gpio in question
1961 * This is used directly or indirectly to implement gpio_cansleep(). It
1962 * returns nonzero if access reading or writing the GPIO value can sleep.
1964 static int gpiod_cansleep(const struct gpio_desc
*desc
)
1968 /* only call this on GPIOs that are valid! */
1969 return desc
->chip
->can_sleep
;
1972 int __gpio_cansleep(unsigned gpio
)
1974 return gpiod_cansleep(gpio_to_desc(gpio
));
1976 EXPORT_SYMBOL_GPL(__gpio_cansleep
);
1979 * __gpio_to_irq() - return the IRQ corresponding to a GPIO
1980 * @gpio: gpio whose IRQ will be returned (already requested)
1983 * This is used directly or indirectly to implement gpio_to_irq().
1984 * It returns the number of the IRQ signaled by this (input) GPIO,
1985 * or a negative errno.
1987 static int gpiod_to_irq(const struct gpio_desc
*desc
)
1989 struct gpio_chip
*chip
;
1995 offset
= gpio_chip_hwgpio(desc
);
1996 return chip
->to_irq
? chip
->to_irq(chip
, offset
) : -ENXIO
;
1999 int __gpio_to_irq(unsigned gpio
)
2001 return gpiod_to_irq(gpio_to_desc(gpio
));
2003 EXPORT_SYMBOL_GPL(__gpio_to_irq
);
2006 /* There's no value in making it easy to inline GPIO calls that may sleep.
2007 * Common examples include ones connected to I2C or SPI chips.
2010 static int gpiod_get_value_cansleep(const struct gpio_desc
*desc
)
2012 struct gpio_chip
*chip
;
2016 might_sleep_if(extra_checks
);
2020 offset
= gpio_chip_hwgpio(desc
);
2021 value
= chip
->get
? chip
->get(chip
, offset
) : 0;
2022 trace_gpio_value(desc_to_gpio(desc
), 1, value
);
2026 int gpio_get_value_cansleep(unsigned gpio
)
2028 return gpiod_get_value_cansleep(gpio_to_desc(gpio
));
2030 EXPORT_SYMBOL_GPL(gpio_get_value_cansleep
);
2032 static void gpiod_set_value_cansleep(struct gpio_desc
*desc
, int value
)
2034 struct gpio_chip
*chip
;
2036 might_sleep_if(extra_checks
);
2040 trace_gpio_value(desc_to_gpio(desc
), 0, value
);
2041 if (test_bit(FLAG_OPEN_DRAIN
, &desc
->flags
))
2042 _gpio_set_open_drain_value(desc
, value
);
2043 else if (test_bit(FLAG_OPEN_SOURCE
, &desc
->flags
))
2044 _gpio_set_open_source_value(desc
, value
);
2046 chip
->set(chip
, gpio_chip_hwgpio(desc
), value
);
2049 void gpio_set_value_cansleep(unsigned gpio
, int value
)
2051 return gpiod_set_value_cansleep(gpio_to_desc(gpio
), value
);
2053 EXPORT_SYMBOL_GPL(gpio_set_value_cansleep
);
2055 #ifdef CONFIG_DEBUG_FS
2057 static void gpiolib_dbg_show(struct seq_file
*s
, struct gpio_chip
*chip
)
2060 unsigned gpio
= chip
->base
;
2061 struct gpio_desc
*gdesc
= &chip
->desc
[0];
2064 for (i
= 0; i
< chip
->ngpio
; i
++, gpio
++, gdesc
++) {
2065 if (!test_bit(FLAG_REQUESTED
, &gdesc
->flags
))
2068 gpiod_get_direction(gdesc
);
2069 is_out
= test_bit(FLAG_IS_OUT
, &gdesc
->flags
);
2070 seq_printf(s
, " gpio-%-3d (%-20.20s) %s %s",
2072 is_out
? "out" : "in ",
2074 ? (chip
->get(chip
, i
) ? "hi" : "lo")
2076 seq_printf(s
, "\n");
2080 static void *gpiolib_seq_start(struct seq_file
*s
, loff_t
*pos
)
2082 unsigned long flags
;
2083 struct gpio_chip
*chip
= NULL
;
2084 loff_t index
= *pos
;
2088 spin_lock_irqsave(&gpio_lock
, flags
);
2089 list_for_each_entry(chip
, &gpio_chips
, list
)
2091 spin_unlock_irqrestore(&gpio_lock
, flags
);
2094 spin_unlock_irqrestore(&gpio_lock
, flags
);
2099 static void *gpiolib_seq_next(struct seq_file
*s
, void *v
, loff_t
*pos
)
2101 unsigned long flags
;
2102 struct gpio_chip
*chip
= v
;
2105 spin_lock_irqsave(&gpio_lock
, flags
);
2106 if (list_is_last(&chip
->list
, &gpio_chips
))
2109 ret
= list_entry(chip
->list
.next
, struct gpio_chip
, list
);
2110 spin_unlock_irqrestore(&gpio_lock
, flags
);
2118 static void gpiolib_seq_stop(struct seq_file
*s
, void *v
)
2122 static int gpiolib_seq_show(struct seq_file
*s
, void *v
)
2124 struct gpio_chip
*chip
= v
;
2127 seq_printf(s
, "%sGPIOs %d-%d", (char *)s
->private,
2128 chip
->base
, chip
->base
+ chip
->ngpio
- 1);
2131 seq_printf(s
, ", %s/%s", dev
->bus
? dev
->bus
->name
: "no-bus",
2134 seq_printf(s
, ", %s", chip
->label
);
2135 if (chip
->can_sleep
)
2136 seq_printf(s
, ", can sleep");
2137 seq_printf(s
, ":\n");
2140 chip
->dbg_show(s
, chip
);
2142 gpiolib_dbg_show(s
, chip
);
2147 static const struct seq_operations gpiolib_seq_ops
= {
2148 .start
= gpiolib_seq_start
,
2149 .next
= gpiolib_seq_next
,
2150 .stop
= gpiolib_seq_stop
,
2151 .show
= gpiolib_seq_show
,
2154 static int gpiolib_open(struct inode
*inode
, struct file
*file
)
2156 return seq_open(file
, &gpiolib_seq_ops
);
2159 static const struct file_operations gpiolib_operations
= {
2160 .owner
= THIS_MODULE
,
2161 .open
= gpiolib_open
,
2163 .llseek
= seq_lseek
,
2164 .release
= seq_release
,
2167 static int __init
gpiolib_debugfs_init(void)
2169 /* /sys/kernel/debug/gpio */
2170 (void) debugfs_create_file("gpio", S_IFREG
| S_IRUGO
,
2171 NULL
, NULL
, &gpiolib_operations
);
2174 subsys_initcall(gpiolib_debugfs_init
);
2176 #endif /* DEBUG_FS */