1 #include <linux/kernel.h>
2 #include <linux/module.h>
3 #include <linux/interrupt.h>
5 #include <linux/spinlock.h>
6 #include <linux/device.h>
8 #include <linux/debugfs.h>
9 #include <linux/seq_file.h>
10 #include <linux/gpio.h>
11 #include <linux/of_gpio.h>
12 #include <linux/idr.h>
13 #include <linux/slab.h>
15 #define CREATE_TRACE_POINTS
16 #include <trace/events/gpio.h>
18 /* Optional implementation infrastructure for GPIO interfaces.
20 * Platforms may want to use this if they tend to use very many GPIOs
21 * that aren't part of a System-On-Chip core; or across I2C/SPI/etc.
23 * When kernel footprint or instruction count is an issue, simpler
24 * implementations may be preferred. The GPIO programming interface
25 * allows for inlining speed-critical get/set operations for common
26 * cases, so that access to SOC-integrated GPIOs can sometimes cost
27 * only an instruction or two per bit.
31 /* When debugging, extend minimal trust to callers and platform code.
32 * Also emit diagnostic messages that may help initial bringup, when
33 * board setup or driver bugs are most common.
35 * Otherwise, minimize overhead in what may be bitbanging codepaths.
38 #define extra_checks 1
40 #define extra_checks 0
43 /* gpio_lock prevents conflicts during gpio_desc[] table updates.
44 * While any GPIO is requested, its gpio_chip is not removable;
45 * each GPIO's "requested" flag serves as a lock and refcount.
47 static DEFINE_SPINLOCK(gpio_lock
);
50 struct gpio_chip
*chip
;
52 /* flag symbols are bit numbers */
53 #define FLAG_REQUESTED 0
55 #define FLAG_RESERVED 2
56 #define FLAG_EXPORT 3 /* protected by sysfs_lock */
57 #define FLAG_SYSFS 4 /* exported via /sys/class/gpio/control */
58 #define FLAG_TRIG_FALL 5 /* trigger on falling edge */
59 #define FLAG_TRIG_RISE 6 /* trigger on rising edge */
60 #define FLAG_ACTIVE_LOW 7 /* sysfs value has active low */
61 #define FLAG_OPEN_DRAIN 8 /* Gpio is open drain type */
62 #define FLAG_OPEN_SOURCE 9 /* Gpio is open source type */
64 #define ID_SHIFT 16 /* add new flags before this one */
66 #define GPIO_FLAGS_MASK ((1 << ID_SHIFT) - 1)
67 #define GPIO_TRIGGER_MASK (BIT(FLAG_TRIG_FALL) | BIT(FLAG_TRIG_RISE))
69 #ifdef CONFIG_DEBUG_FS
73 static struct gpio_desc gpio_desc
[ARCH_NR_GPIOS
];
75 #ifdef CONFIG_GPIO_SYSFS
76 static DEFINE_IDR(dirent_idr
);
79 static inline void desc_set_label(struct gpio_desc
*d
, const char *label
)
81 #ifdef CONFIG_DEBUG_FS
86 /* Warn when drivers omit gpio_request() calls -- legal but ill-advised
87 * when setting direction, and otherwise illegal. Until board setup code
88 * and drivers use explicit requests everywhere (which won't happen when
89 * those calls have no teeth) we can't avoid autorequesting. This nag
90 * message should motivate switching to explicit requests... so should
91 * the weaker cleanup after faults, compared to gpio_request().
93 * NOTE: the autorequest mechanism is going away; at this point it's
94 * only "legal" in the sense that (old) code using it won't break yet,
95 * but instead only triggers a WARN() stack dump.
97 static int gpio_ensure_requested(struct gpio_desc
*desc
, unsigned offset
)
99 const struct gpio_chip
*chip
= desc
->chip
;
100 const int gpio
= chip
->base
+ offset
;
102 if (WARN(test_and_set_bit(FLAG_REQUESTED
, &desc
->flags
) == 0,
103 "autorequest GPIO-%d\n", gpio
)) {
104 if (!try_module_get(chip
->owner
)) {
105 pr_err("GPIO-%d: module can't be gotten \n", gpio
);
106 clear_bit(FLAG_REQUESTED
, &desc
->flags
);
110 desc_set_label(desc
, "[auto]");
111 /* caller must chip->request() w/o spinlock */
118 /* caller holds gpio_lock *OR* gpio is marked as requested */
119 struct gpio_chip
*gpio_to_chip(unsigned gpio
)
121 return gpio_desc
[gpio
].chip
;
124 /* dynamic allocation of GPIOs, e.g. on a hotplugged device */
125 static int gpiochip_find_base(int ngpio
)
131 for (i
= ARCH_NR_GPIOS
- 1; i
>= 0 ; i
--) {
132 struct gpio_desc
*desc
= &gpio_desc
[i
];
133 struct gpio_chip
*chip
= desc
->chip
;
135 if (!chip
&& !test_bit(FLAG_RESERVED
, &desc
->flags
)) {
137 if (spare
== ngpio
) {
144 i
-= chip
->ngpio
- 1;
148 if (gpio_is_valid(base
))
149 pr_debug("%s: found new base at %d\n", __func__
, base
);
154 * gpiochip_reserve() - reserve range of gpios to use with platform code only
155 * @start: starting gpio number
156 * @ngpio: number of gpios to reserve
157 * Context: platform init, potentially before irqs or kmalloc will work
159 * Returns a negative errno if any gpio within the range is already reserved
160 * or registered, else returns zero as a success code. Use this function
161 * to mark a range of gpios as unavailable for dynamic gpio number allocation,
162 * for example because its driver support is not yet loaded.
164 int __init
gpiochip_reserve(int start
, int ngpio
)
170 if (!gpio_is_valid(start
) || !gpio_is_valid(start
+ ngpio
- 1))
173 spin_lock_irqsave(&gpio_lock
, flags
);
175 for (i
= start
; i
< start
+ ngpio
; i
++) {
176 struct gpio_desc
*desc
= &gpio_desc
[i
];
178 if (desc
->chip
|| test_bit(FLAG_RESERVED
, &desc
->flags
)) {
183 set_bit(FLAG_RESERVED
, &desc
->flags
);
186 pr_debug("%s: reserved gpios from %d to %d\n",
187 __func__
, start
, start
+ ngpio
- 1);
189 spin_unlock_irqrestore(&gpio_lock
, flags
);
194 /* caller ensures gpio is valid and requested, chip->get_direction may sleep */
195 static int gpio_get_direction(unsigned gpio
)
197 struct gpio_chip
*chip
;
198 struct gpio_desc
*desc
= &gpio_desc
[gpio
];
199 int status
= -EINVAL
;
201 chip
= gpio_to_chip(gpio
);
204 if (!chip
->get_direction
)
207 status
= chip
->get_direction(chip
, gpio
);
209 /* GPIOF_DIR_IN, or other positive */
211 clear_bit(FLAG_IS_OUT
, &desc
->flags
);
215 set_bit(FLAG_IS_OUT
, &desc
->flags
);
220 #ifdef CONFIG_GPIO_SYSFS
222 /* lock protects against unexport_gpio() being called while
223 * sysfs files are active.
225 static DEFINE_MUTEX(sysfs_lock
);
228 * /sys/class/gpio/gpioN... only for GPIOs that are exported
230 * * MAY BE OMITTED if kernel won't allow direction changes
231 * * is read/write as "in" or "out"
232 * * may also be written as "high" or "low", initializing
233 * output value as specified ("out" implies "low")
235 * * always readable, subject to hardware behavior
236 * * may be writable, as zero/nonzero
238 * * configures behavior of poll(2) on /value
239 * * available only if pin can generate IRQs on input
240 * * is read/write as "none", "falling", "rising", or "both"
242 * * configures polarity of /value
243 * * is read/write as zero/nonzero
244 * * also affects existing and subsequent "falling" and "rising"
245 * /edge configuration
248 static ssize_t
gpio_direction_show(struct device
*dev
,
249 struct device_attribute
*attr
, char *buf
)
251 const struct gpio_desc
*desc
= dev_get_drvdata(dev
);
252 unsigned gpio
= desc
- gpio_desc
;
255 mutex_lock(&sysfs_lock
);
257 if (!test_bit(FLAG_EXPORT
, &desc
->flags
))
260 gpio_get_direction(gpio
);
261 status
= sprintf(buf
, "%s\n",
262 test_bit(FLAG_IS_OUT
, &desc
->flags
)
265 mutex_unlock(&sysfs_lock
);
269 static ssize_t
gpio_direction_store(struct device
*dev
,
270 struct device_attribute
*attr
, const char *buf
, size_t size
)
272 const struct gpio_desc
*desc
= dev_get_drvdata(dev
);
273 unsigned gpio
= desc
- gpio_desc
;
276 mutex_lock(&sysfs_lock
);
278 if (!test_bit(FLAG_EXPORT
, &desc
->flags
))
280 else if (sysfs_streq(buf
, "high"))
281 status
= gpio_direction_output(gpio
, 1);
282 else if (sysfs_streq(buf
, "out") || sysfs_streq(buf
, "low"))
283 status
= gpio_direction_output(gpio
, 0);
284 else if (sysfs_streq(buf
, "in"))
285 status
= gpio_direction_input(gpio
);
289 mutex_unlock(&sysfs_lock
);
290 return status
? : size
;
293 static /* const */ DEVICE_ATTR(direction
, 0644,
294 gpio_direction_show
, gpio_direction_store
);
296 static ssize_t
gpio_value_show(struct device
*dev
,
297 struct device_attribute
*attr
, char *buf
)
299 const struct gpio_desc
*desc
= dev_get_drvdata(dev
);
300 unsigned gpio
= desc
- gpio_desc
;
303 mutex_lock(&sysfs_lock
);
305 if (!test_bit(FLAG_EXPORT
, &desc
->flags
)) {
310 value
= !!gpio_get_value_cansleep(gpio
);
311 if (test_bit(FLAG_ACTIVE_LOW
, &desc
->flags
))
314 status
= sprintf(buf
, "%d\n", value
);
317 mutex_unlock(&sysfs_lock
);
321 static ssize_t
gpio_value_store(struct device
*dev
,
322 struct device_attribute
*attr
, const char *buf
, size_t size
)
324 const struct gpio_desc
*desc
= dev_get_drvdata(dev
);
325 unsigned gpio
= desc
- gpio_desc
;
328 mutex_lock(&sysfs_lock
);
330 if (!test_bit(FLAG_EXPORT
, &desc
->flags
))
332 else if (!test_bit(FLAG_IS_OUT
, &desc
->flags
))
337 status
= strict_strtol(buf
, 0, &value
);
339 if (test_bit(FLAG_ACTIVE_LOW
, &desc
->flags
))
341 gpio_set_value_cansleep(gpio
, value
!= 0);
346 mutex_unlock(&sysfs_lock
);
350 static const DEVICE_ATTR(value
, 0644,
351 gpio_value_show
, gpio_value_store
);
353 static irqreturn_t
gpio_sysfs_irq(int irq
, void *priv
)
355 struct sysfs_dirent
*value_sd
= priv
;
357 sysfs_notify_dirent(value_sd
);
361 static int gpio_setup_irq(struct gpio_desc
*desc
, struct device
*dev
,
362 unsigned long gpio_flags
)
364 struct sysfs_dirent
*value_sd
;
365 unsigned long irq_flags
;
368 if ((desc
->flags
& GPIO_TRIGGER_MASK
) == gpio_flags
)
371 irq
= gpio_to_irq(desc
- gpio_desc
);
375 id
= desc
->flags
>> ID_SHIFT
;
376 value_sd
= idr_find(&dirent_idr
, id
);
378 free_irq(irq
, value_sd
);
380 desc
->flags
&= ~GPIO_TRIGGER_MASK
;
387 irq_flags
= IRQF_SHARED
;
388 if (test_bit(FLAG_TRIG_FALL
, &gpio_flags
))
389 irq_flags
|= test_bit(FLAG_ACTIVE_LOW
, &desc
->flags
) ?
390 IRQF_TRIGGER_RISING
: IRQF_TRIGGER_FALLING
;
391 if (test_bit(FLAG_TRIG_RISE
, &gpio_flags
))
392 irq_flags
|= test_bit(FLAG_ACTIVE_LOW
, &desc
->flags
) ?
393 IRQF_TRIGGER_FALLING
: IRQF_TRIGGER_RISING
;
396 value_sd
= sysfs_get_dirent(dev
->kobj
.sd
, NULL
, "value");
404 if (idr_pre_get(&dirent_idr
, GFP_KERNEL
))
405 ret
= idr_get_new_above(&dirent_idr
, value_sd
,
407 } while (ret
== -EAGAIN
);
412 desc
->flags
&= GPIO_FLAGS_MASK
;
413 desc
->flags
|= (unsigned long)id
<< ID_SHIFT
;
415 if (desc
->flags
>> ID_SHIFT
!= id
) {
421 ret
= request_any_context_irq(irq
, gpio_sysfs_irq
, irq_flags
,
422 "gpiolib", value_sd
);
426 desc
->flags
|= gpio_flags
;
430 idr_remove(&dirent_idr
, id
);
431 desc
->flags
&= GPIO_FLAGS_MASK
;
439 static const struct {
442 } trigger_types
[] = {
444 { "falling", BIT(FLAG_TRIG_FALL
) },
445 { "rising", BIT(FLAG_TRIG_RISE
) },
446 { "both", BIT(FLAG_TRIG_FALL
) | BIT(FLAG_TRIG_RISE
) },
449 static ssize_t
gpio_edge_show(struct device
*dev
,
450 struct device_attribute
*attr
, char *buf
)
452 const struct gpio_desc
*desc
= dev_get_drvdata(dev
);
455 mutex_lock(&sysfs_lock
);
457 if (!test_bit(FLAG_EXPORT
, &desc
->flags
))
463 for (i
= 0; i
< ARRAY_SIZE(trigger_types
); i
++)
464 if ((desc
->flags
& GPIO_TRIGGER_MASK
)
465 == trigger_types
[i
].flags
) {
466 status
= sprintf(buf
, "%s\n",
467 trigger_types
[i
].name
);
472 mutex_unlock(&sysfs_lock
);
476 static ssize_t
gpio_edge_store(struct device
*dev
,
477 struct device_attribute
*attr
, const char *buf
, size_t size
)
479 struct gpio_desc
*desc
= dev_get_drvdata(dev
);
483 for (i
= 0; i
< ARRAY_SIZE(trigger_types
); i
++)
484 if (sysfs_streq(trigger_types
[i
].name
, buf
))
489 mutex_lock(&sysfs_lock
);
491 if (!test_bit(FLAG_EXPORT
, &desc
->flags
))
494 status
= gpio_setup_irq(desc
, dev
, trigger_types
[i
].flags
);
499 mutex_unlock(&sysfs_lock
);
504 static DEVICE_ATTR(edge
, 0644, gpio_edge_show
, gpio_edge_store
);
506 static int sysfs_set_active_low(struct gpio_desc
*desc
, struct device
*dev
,
511 if (!!test_bit(FLAG_ACTIVE_LOW
, &desc
->flags
) == !!value
)
515 set_bit(FLAG_ACTIVE_LOW
, &desc
->flags
);
517 clear_bit(FLAG_ACTIVE_LOW
, &desc
->flags
);
519 /* reconfigure poll(2) support if enabled on one edge only */
520 if (dev
!= NULL
&& (!!test_bit(FLAG_TRIG_RISE
, &desc
->flags
) ^
521 !!test_bit(FLAG_TRIG_FALL
, &desc
->flags
))) {
522 unsigned long trigger_flags
= desc
->flags
& GPIO_TRIGGER_MASK
;
524 gpio_setup_irq(desc
, dev
, 0);
525 status
= gpio_setup_irq(desc
, dev
, trigger_flags
);
531 static ssize_t
gpio_active_low_show(struct device
*dev
,
532 struct device_attribute
*attr
, char *buf
)
534 const struct gpio_desc
*desc
= dev_get_drvdata(dev
);
537 mutex_lock(&sysfs_lock
);
539 if (!test_bit(FLAG_EXPORT
, &desc
->flags
))
542 status
= sprintf(buf
, "%d\n",
543 !!test_bit(FLAG_ACTIVE_LOW
, &desc
->flags
));
545 mutex_unlock(&sysfs_lock
);
550 static ssize_t
gpio_active_low_store(struct device
*dev
,
551 struct device_attribute
*attr
, const char *buf
, size_t size
)
553 struct gpio_desc
*desc
= dev_get_drvdata(dev
);
556 mutex_lock(&sysfs_lock
);
558 if (!test_bit(FLAG_EXPORT
, &desc
->flags
)) {
563 status
= strict_strtol(buf
, 0, &value
);
565 status
= sysfs_set_active_low(desc
, dev
, value
!= 0);
568 mutex_unlock(&sysfs_lock
);
570 return status
? : size
;
573 static const DEVICE_ATTR(active_low
, 0644,
574 gpio_active_low_show
, gpio_active_low_store
);
576 static const struct attribute
*gpio_attrs
[] = {
577 &dev_attr_value
.attr
,
578 &dev_attr_active_low
.attr
,
582 static const struct attribute_group gpio_attr_group
= {
583 .attrs
= (struct attribute
**) gpio_attrs
,
587 * /sys/class/gpio/gpiochipN/
588 * /base ... matching gpio_chip.base (N)
589 * /label ... matching gpio_chip.label
590 * /ngpio ... matching gpio_chip.ngpio
593 static ssize_t
chip_base_show(struct device
*dev
,
594 struct device_attribute
*attr
, char *buf
)
596 const struct gpio_chip
*chip
= dev_get_drvdata(dev
);
598 return sprintf(buf
, "%d\n", chip
->base
);
600 static DEVICE_ATTR(base
, 0444, chip_base_show
, NULL
);
602 static ssize_t
chip_label_show(struct device
*dev
,
603 struct device_attribute
*attr
, char *buf
)
605 const struct gpio_chip
*chip
= dev_get_drvdata(dev
);
607 return sprintf(buf
, "%s\n", chip
->label
? : "");
609 static DEVICE_ATTR(label
, 0444, chip_label_show
, NULL
);
611 static ssize_t
chip_ngpio_show(struct device
*dev
,
612 struct device_attribute
*attr
, char *buf
)
614 const struct gpio_chip
*chip
= dev_get_drvdata(dev
);
616 return sprintf(buf
, "%u\n", chip
->ngpio
);
618 static DEVICE_ATTR(ngpio
, 0444, chip_ngpio_show
, NULL
);
620 static const struct attribute
*gpiochip_attrs
[] = {
622 &dev_attr_label
.attr
,
623 &dev_attr_ngpio
.attr
,
627 static const struct attribute_group gpiochip_attr_group
= {
628 .attrs
= (struct attribute
**) gpiochip_attrs
,
632 * /sys/class/gpio/export ... write-only
633 * integer N ... number of GPIO to export (full access)
634 * /sys/class/gpio/unexport ... write-only
635 * integer N ... number of GPIO to unexport
637 static ssize_t
export_store(struct class *class,
638 struct class_attribute
*attr
,
639 const char *buf
, size_t len
)
644 status
= strict_strtol(buf
, 0, &gpio
);
648 /* No extra locking here; FLAG_SYSFS just signifies that the
649 * request and export were done by on behalf of userspace, so
650 * they may be undone on its behalf too.
653 status
= gpio_request(gpio
, "sysfs");
655 if (status
== -EPROBE_DEFER
)
659 status
= gpio_export(gpio
, true);
663 set_bit(FLAG_SYSFS
, &gpio_desc
[gpio
].flags
);
667 pr_debug("%s: status %d\n", __func__
, status
);
668 return status
? : len
;
671 static ssize_t
unexport_store(struct class *class,
672 struct class_attribute
*attr
,
673 const char *buf
, size_t len
)
678 status
= strict_strtol(buf
, 0, &gpio
);
684 /* reject bogus commands (gpio_unexport ignores them) */
685 if (!gpio_is_valid(gpio
))
688 /* No extra locking here; FLAG_SYSFS just signifies that the
689 * request and export were done by on behalf of userspace, so
690 * they may be undone on its behalf too.
692 if (test_and_clear_bit(FLAG_SYSFS
, &gpio_desc
[gpio
].flags
)) {
698 pr_debug("%s: status %d\n", __func__
, status
);
699 return status
? : len
;
702 static struct class_attribute gpio_class_attrs
[] = {
703 __ATTR(export
, 0200, NULL
, export_store
),
704 __ATTR(unexport
, 0200, NULL
, unexport_store
),
708 static struct class gpio_class
= {
710 .owner
= THIS_MODULE
,
712 .class_attrs
= gpio_class_attrs
,
717 * gpio_export - export a GPIO through sysfs
718 * @gpio: gpio to make available, already requested
719 * @direction_may_change: true if userspace may change gpio direction
720 * Context: arch_initcall or later
722 * When drivers want to make a GPIO accessible to userspace after they
723 * have requested it -- perhaps while debugging, or as part of their
724 * public interface -- they may use this routine. If the GPIO can
725 * change direction (some can't) and the caller allows it, userspace
726 * will see "direction" sysfs attribute which may be used to change
727 * the gpio's direction. A "value" attribute will always be provided.
729 * Returns zero on success, else an error.
731 int gpio_export(unsigned gpio
, bool direction_may_change
)
734 struct gpio_desc
*desc
;
736 const char *ioname
= NULL
;
739 /* can't export until sysfs is available ... */
741 pr_debug("%s: called too early!\n", __func__
);
745 if (!gpio_is_valid(gpio
)) {
746 pr_debug("%s: gpio %d is not valid\n", __func__
, gpio
);
750 mutex_lock(&sysfs_lock
);
752 spin_lock_irqsave(&gpio_lock
, flags
);
753 desc
= &gpio_desc
[gpio
];
754 if (!test_bit(FLAG_REQUESTED
, &desc
->flags
) ||
755 test_bit(FLAG_EXPORT
, &desc
->flags
)) {
756 spin_unlock_irqrestore(&gpio_lock
, flags
);
757 pr_debug("%s: gpio %d unavailable (requested=%d, exported=%d)\n",
759 test_bit(FLAG_REQUESTED
, &desc
->flags
),
760 test_bit(FLAG_EXPORT
, &desc
->flags
));
765 if (!desc
->chip
->direction_input
|| !desc
->chip
->direction_output
)
766 direction_may_change
= false;
767 spin_unlock_irqrestore(&gpio_lock
, flags
);
769 if (desc
->chip
->names
&& desc
->chip
->names
[gpio
- desc
->chip
->base
])
770 ioname
= desc
->chip
->names
[gpio
- desc
->chip
->base
];
772 dev
= device_create(&gpio_class
, desc
->chip
->dev
, MKDEV(0, 0),
773 desc
, ioname
? ioname
: "gpio%u", gpio
);
775 status
= PTR_ERR(dev
);
779 status
= sysfs_create_group(&dev
->kobj
, &gpio_attr_group
);
781 goto fail_unregister_device
;
783 if (direction_may_change
) {
784 status
= device_create_file(dev
, &dev_attr_direction
);
786 goto fail_unregister_device
;
789 if (gpio_to_irq(gpio
) >= 0 && (direction_may_change
||
790 !test_bit(FLAG_IS_OUT
, &desc
->flags
))) {
791 status
= device_create_file(dev
, &dev_attr_edge
);
793 goto fail_unregister_device
;
796 set_bit(FLAG_EXPORT
, &desc
->flags
);
797 mutex_unlock(&sysfs_lock
);
800 fail_unregister_device
:
801 device_unregister(dev
);
803 mutex_unlock(&sysfs_lock
);
804 pr_debug("%s: gpio%d status %d\n", __func__
, gpio
, status
);
807 EXPORT_SYMBOL_GPL(gpio_export
);
809 static int match_export(struct device
*dev
, const void *data
)
811 return dev_get_drvdata(dev
) == data
;
815 * gpio_export_link - create a sysfs link to an exported GPIO node
816 * @dev: device under which to create symlink
817 * @name: name of the symlink
818 * @gpio: gpio to create symlink to, already exported
820 * Set up a symlink from /sys/.../dev/name to /sys/class/gpio/gpioN
821 * node. Caller is responsible for unlinking.
823 * Returns zero on success, else an error.
825 int gpio_export_link(struct device
*dev
, const char *name
, unsigned gpio
)
827 struct gpio_desc
*desc
;
828 int status
= -EINVAL
;
830 if (!gpio_is_valid(gpio
))
833 mutex_lock(&sysfs_lock
);
835 desc
= &gpio_desc
[gpio
];
837 if (test_bit(FLAG_EXPORT
, &desc
->flags
)) {
840 tdev
= class_find_device(&gpio_class
, NULL
, desc
, match_export
);
842 status
= sysfs_create_link(&dev
->kobj
, &tdev
->kobj
,
849 mutex_unlock(&sysfs_lock
);
853 pr_debug("%s: gpio%d status %d\n", __func__
, gpio
, status
);
857 EXPORT_SYMBOL_GPL(gpio_export_link
);
861 * gpio_sysfs_set_active_low - set the polarity of gpio sysfs value
862 * @gpio: gpio to change
863 * @value: non-zero to use active low, i.e. inverted values
865 * Set the polarity of /sys/class/gpio/gpioN/value sysfs attribute.
866 * The GPIO does not have to be exported yet. If poll(2) support has
867 * been enabled for either rising or falling edge, it will be
868 * reconfigured to follow the new polarity.
870 * Returns zero on success, else an error.
872 int gpio_sysfs_set_active_low(unsigned gpio
, int value
)
874 struct gpio_desc
*desc
;
875 struct device
*dev
= NULL
;
876 int status
= -EINVAL
;
878 if (!gpio_is_valid(gpio
))
881 mutex_lock(&sysfs_lock
);
883 desc
= &gpio_desc
[gpio
];
885 if (test_bit(FLAG_EXPORT
, &desc
->flags
)) {
886 dev
= class_find_device(&gpio_class
, NULL
, desc
, match_export
);
893 status
= sysfs_set_active_low(desc
, dev
, value
);
896 mutex_unlock(&sysfs_lock
);
900 pr_debug("%s: gpio%d status %d\n", __func__
, gpio
, status
);
904 EXPORT_SYMBOL_GPL(gpio_sysfs_set_active_low
);
907 * gpio_unexport - reverse effect of gpio_export()
908 * @gpio: gpio to make unavailable
910 * This is implicit on gpio_free().
912 void gpio_unexport(unsigned gpio
)
914 struct gpio_desc
*desc
;
916 struct device
*dev
= NULL
;
918 if (!gpio_is_valid(gpio
)) {
923 mutex_lock(&sysfs_lock
);
925 desc
= &gpio_desc
[gpio
];
927 if (test_bit(FLAG_EXPORT
, &desc
->flags
)) {
929 dev
= class_find_device(&gpio_class
, NULL
, desc
, match_export
);
931 gpio_setup_irq(desc
, dev
, 0);
932 clear_bit(FLAG_EXPORT
, &desc
->flags
);
937 mutex_unlock(&sysfs_lock
);
939 device_unregister(dev
);
944 pr_debug("%s: gpio%d status %d\n", __func__
, gpio
, status
);
946 EXPORT_SYMBOL_GPL(gpio_unexport
);
948 static int gpiochip_export(struct gpio_chip
*chip
)
953 /* Many systems register gpio chips for SOC support very early,
954 * before driver model support is available. In those cases we
955 * export this later, in gpiolib_sysfs_init() ... here we just
956 * verify that _some_ field of gpio_class got initialized.
961 /* use chip->base for the ID; it's already known to be unique */
962 mutex_lock(&sysfs_lock
);
963 dev
= device_create(&gpio_class
, chip
->dev
, MKDEV(0, 0), chip
,
964 "gpiochip%d", chip
->base
);
966 status
= sysfs_create_group(&dev
->kobj
,
967 &gpiochip_attr_group
);
969 status
= PTR_ERR(dev
);
970 chip
->exported
= (status
== 0);
971 mutex_unlock(&sysfs_lock
);
977 spin_lock_irqsave(&gpio_lock
, flags
);
979 while (gpio_desc
[gpio
].chip
== chip
)
980 gpio_desc
[gpio
++].chip
= NULL
;
981 spin_unlock_irqrestore(&gpio_lock
, flags
);
983 pr_debug("%s: chip %s status %d\n", __func__
,
984 chip
->label
, status
);
990 static void gpiochip_unexport(struct gpio_chip
*chip
)
995 mutex_lock(&sysfs_lock
);
996 dev
= class_find_device(&gpio_class
, NULL
, chip
, match_export
);
999 device_unregister(dev
);
1004 mutex_unlock(&sysfs_lock
);
1007 pr_debug("%s: chip %s status %d\n", __func__
,
1008 chip
->label
, status
);
1011 static int __init
gpiolib_sysfs_init(void)
1014 unsigned long flags
;
1017 status
= class_register(&gpio_class
);
1021 /* Scan and register the gpio_chips which registered very
1022 * early (e.g. before the class_register above was called).
1024 * We run before arch_initcall() so chip->dev nodes can have
1025 * registered, and so arch_initcall() can always gpio_export().
1027 spin_lock_irqsave(&gpio_lock
, flags
);
1028 for (gpio
= 0; gpio
< ARCH_NR_GPIOS
; gpio
++) {
1029 struct gpio_chip
*chip
;
1031 chip
= gpio_desc
[gpio
].chip
;
1032 if (!chip
|| chip
->exported
)
1035 spin_unlock_irqrestore(&gpio_lock
, flags
);
1036 status
= gpiochip_export(chip
);
1037 spin_lock_irqsave(&gpio_lock
, flags
);
1039 spin_unlock_irqrestore(&gpio_lock
, flags
);
1044 postcore_initcall(gpiolib_sysfs_init
);
1047 static inline int gpiochip_export(struct gpio_chip
*chip
)
1052 static inline void gpiochip_unexport(struct gpio_chip
*chip
)
1056 #endif /* CONFIG_GPIO_SYSFS */
1059 * gpiochip_add() - register a gpio_chip
1060 * @chip: the chip to register, with chip->base initialized
1061 * Context: potentially before irqs or kmalloc will work
1063 * Returns a negative errno if the chip can't be registered, such as
1064 * because the chip->base is invalid or already associated with a
1065 * different chip. Otherwise it returns zero as a success code.
1067 * When gpiochip_add() is called very early during boot, so that GPIOs
1068 * can be freely used, the chip->dev device must be registered before
1069 * the gpio framework's arch_initcall(). Otherwise sysfs initialization
1070 * for GPIOs will fail rudely.
1072 * If chip->base is negative, this requests dynamic assignment of
1073 * a range of valid GPIOs.
1075 int gpiochip_add(struct gpio_chip
*chip
)
1077 unsigned long flags
;
1080 int base
= chip
->base
;
1082 if ((!gpio_is_valid(base
) || !gpio_is_valid(base
+ chip
->ngpio
- 1))
1088 spin_lock_irqsave(&gpio_lock
, flags
);
1091 base
= gpiochip_find_base(chip
->ngpio
);
1099 /* these GPIO numbers must not be managed by another gpio_chip */
1100 for (id
= base
; id
< base
+ chip
->ngpio
; id
++) {
1101 if (gpio_desc
[id
].chip
!= NULL
) {
1107 for (id
= base
; id
< base
+ chip
->ngpio
; id
++) {
1108 gpio_desc
[id
].chip
= chip
;
1110 /* REVISIT: most hardware initializes GPIOs as
1111 * inputs (often with pullups enabled) so power
1112 * usage is minimized. Linux code should set the
1113 * gpio direction first thing; but until it does,
1114 * and in case chip->get_direction is not set,
1115 * we may expose the wrong direction in sysfs.
1117 gpio_desc
[id
].flags
= !chip
->direction_input
1118 ? (1 << FLAG_IS_OUT
)
1123 #ifdef CONFIG_PINCTRL
1124 INIT_LIST_HEAD(&chip
->pin_ranges
);
1127 of_gpiochip_add(chip
);
1130 spin_unlock_irqrestore(&gpio_lock
, flags
);
1135 status
= gpiochip_export(chip
);
1139 pr_debug("gpiochip_add: registered GPIOs %d to %d on device: %s\n",
1140 chip
->base
, chip
->base
+ chip
->ngpio
- 1,
1141 chip
->label
? : "generic");
1145 /* failures here can mean systems won't boot... */
1146 pr_err("gpiochip_add: gpios %d..%d (%s) failed to register\n",
1147 chip
->base
, chip
->base
+ chip
->ngpio
- 1,
1148 chip
->label
? : "generic");
1151 EXPORT_SYMBOL_GPL(gpiochip_add
);
1154 * gpiochip_remove() - unregister a gpio_chip
1155 * @chip: the chip to unregister
1157 * A gpio_chip with any GPIOs still requested may not be removed.
1159 int gpiochip_remove(struct gpio_chip
*chip
)
1161 unsigned long flags
;
1165 spin_lock_irqsave(&gpio_lock
, flags
);
1167 gpiochip_remove_pin_ranges(chip
);
1168 of_gpiochip_remove(chip
);
1170 for (id
= chip
->base
; id
< chip
->base
+ chip
->ngpio
; id
++) {
1171 if (test_bit(FLAG_REQUESTED
, &gpio_desc
[id
].flags
)) {
1177 for (id
= chip
->base
; id
< chip
->base
+ chip
->ngpio
; id
++)
1178 gpio_desc
[id
].chip
= NULL
;
1181 spin_unlock_irqrestore(&gpio_lock
, flags
);
1184 gpiochip_unexport(chip
);
1188 EXPORT_SYMBOL_GPL(gpiochip_remove
);
1191 * gpiochip_find() - iterator for locating a specific gpio_chip
1192 * @data: data to pass to match function
1193 * @callback: Callback function to check gpio_chip
1195 * Similar to bus_find_device. It returns a reference to a gpio_chip as
1196 * determined by a user supplied @match callback. The callback should return
1197 * 0 if the device doesn't match and non-zero if it does. If the callback is
1198 * non-zero, this function will return to the caller and not iterate over any
1201 struct gpio_chip
*gpiochip_find(void *data
,
1202 int (*match
)(struct gpio_chip
*chip
,
1205 struct gpio_chip
*chip
= NULL
;
1206 unsigned long flags
;
1209 spin_lock_irqsave(&gpio_lock
, flags
);
1210 for (i
= 0; i
< ARCH_NR_GPIOS
; i
++) {
1211 if (!gpio_desc
[i
].chip
)
1214 if (match(gpio_desc
[i
].chip
, data
)) {
1215 chip
= gpio_desc
[i
].chip
;
1219 spin_unlock_irqrestore(&gpio_lock
, flags
);
1223 EXPORT_SYMBOL_GPL(gpiochip_find
);
1225 #ifdef CONFIG_PINCTRL
1228 * gpiochip_add_pin_range() - add a range for GPIO <-> pin mapping
1229 * @chip: the gpiochip to add the range for
1230 * @pinctrl_name: the dev_name() of the pin controller to map to
1231 * @gpio_offset: the start offset in the current gpio_chip number space
1232 * @pin_offset: the start offset in the pin controller number space
1233 * @npins: the number of pins from the offset of each pin space (GPIO and
1234 * pin controller) to accumulate in this range
1236 int gpiochip_add_pin_range(struct gpio_chip
*chip
, const char *pinctl_name
,
1237 unsigned int gpio_offset
, unsigned int pin_offset
,
1240 struct gpio_pin_range
*pin_range
;
1243 pin_range
= kzalloc(sizeof(*pin_range
), GFP_KERNEL
);
1245 pr_err("%s: GPIO chip: failed to allocate pin ranges\n",
1250 /* Use local offset as range ID */
1251 pin_range
->range
.id
= gpio_offset
;
1252 pin_range
->range
.gc
= chip
;
1253 pin_range
->range
.name
= chip
->label
;
1254 pin_range
->range
.base
= chip
->base
+ gpio_offset
;
1255 pin_range
->range
.pin_base
= pin_offset
;
1256 pin_range
->range
.npins
= npins
;
1257 pin_range
->pctldev
= pinctrl_find_and_add_gpio_range(pinctl_name
,
1259 if (IS_ERR(pin_range
->pctldev
)) {
1260 ret
= PTR_ERR(pin_range
->pctldev
);
1261 pr_err("%s: GPIO chip: could not create pin range\n",
1266 pr_debug("GPIO chip %s: created GPIO range %d->%d ==> %s PIN %d->%d\n",
1267 chip
->label
, gpio_offset
, gpio_offset
+ npins
- 1,
1269 pin_offset
, pin_offset
+ npins
- 1);
1271 list_add_tail(&pin_range
->node
, &chip
->pin_ranges
);
1275 EXPORT_SYMBOL_GPL(gpiochip_add_pin_range
);
1278 * gpiochip_remove_pin_ranges() - remove all the GPIO <-> pin mappings
1279 * @chip: the chip to remove all the mappings for
1281 void gpiochip_remove_pin_ranges(struct gpio_chip
*chip
)
1283 struct gpio_pin_range
*pin_range
, *tmp
;
1285 list_for_each_entry_safe(pin_range
, tmp
, &chip
->pin_ranges
, node
) {
1286 list_del(&pin_range
->node
);
1287 pinctrl_remove_gpio_range(pin_range
->pctldev
,
1292 EXPORT_SYMBOL_GPL(gpiochip_remove_pin_ranges
);
1294 #endif /* CONFIG_PINCTRL */
1296 /* These "optional" allocation calls help prevent drivers from stomping
1297 * on each other, and help provide better diagnostics in debugfs.
1298 * They're called even less than the "set direction" calls.
1300 int gpio_request(unsigned gpio
, const char *label
)
1302 struct gpio_desc
*desc
;
1303 struct gpio_chip
*chip
;
1304 int status
= -EPROBE_DEFER
;
1305 unsigned long flags
;
1307 spin_lock_irqsave(&gpio_lock
, flags
);
1309 if (!gpio_is_valid(gpio
)) {
1313 desc
= &gpio_desc
[gpio
];
1318 if (!try_module_get(chip
->owner
))
1321 /* NOTE: gpio_request() can be called in early boot,
1322 * before IRQs are enabled, for non-sleeping (SOC) GPIOs.
1325 if (test_and_set_bit(FLAG_REQUESTED
, &desc
->flags
) == 0) {
1326 desc_set_label(desc
, label
? : "?");
1330 module_put(chip
->owner
);
1334 if (chip
->request
) {
1335 /* chip->request may sleep */
1336 spin_unlock_irqrestore(&gpio_lock
, flags
);
1337 status
= chip
->request(chip
, gpio
- chip
->base
);
1338 spin_lock_irqsave(&gpio_lock
, flags
);
1341 desc_set_label(desc
, NULL
);
1342 module_put(chip
->owner
);
1343 clear_bit(FLAG_REQUESTED
, &desc
->flags
);
1347 if (chip
->get_direction
) {
1348 /* chip->get_direction may sleep */
1349 spin_unlock_irqrestore(&gpio_lock
, flags
);
1350 gpio_get_direction(gpio
);
1351 spin_lock_irqsave(&gpio_lock
, flags
);
1355 pr_debug("gpio_request: gpio-%d (%s) status %d\n",
1356 gpio
, label
? : "?", status
);
1357 spin_unlock_irqrestore(&gpio_lock
, flags
);
1360 EXPORT_SYMBOL_GPL(gpio_request
);
1362 void gpio_free(unsigned gpio
)
1364 unsigned long flags
;
1365 struct gpio_desc
*desc
;
1366 struct gpio_chip
*chip
;
1370 if (!gpio_is_valid(gpio
)) {
1371 WARN_ON(extra_checks
);
1375 gpio_unexport(gpio
);
1377 spin_lock_irqsave(&gpio_lock
, flags
);
1379 desc
= &gpio_desc
[gpio
];
1381 if (chip
&& test_bit(FLAG_REQUESTED
, &desc
->flags
)) {
1383 spin_unlock_irqrestore(&gpio_lock
, flags
);
1384 might_sleep_if(chip
->can_sleep
);
1385 chip
->free(chip
, gpio
- chip
->base
);
1386 spin_lock_irqsave(&gpio_lock
, flags
);
1388 desc_set_label(desc
, NULL
);
1389 module_put(desc
->chip
->owner
);
1390 clear_bit(FLAG_ACTIVE_LOW
, &desc
->flags
);
1391 clear_bit(FLAG_REQUESTED
, &desc
->flags
);
1392 clear_bit(FLAG_OPEN_DRAIN
, &desc
->flags
);
1393 clear_bit(FLAG_OPEN_SOURCE
, &desc
->flags
);
1395 WARN_ON(extra_checks
);
1397 spin_unlock_irqrestore(&gpio_lock
, flags
);
1399 EXPORT_SYMBOL_GPL(gpio_free
);
1402 * gpio_request_one - request a single GPIO with initial configuration
1403 * @gpio: the GPIO number
1404 * @flags: GPIO configuration as specified by GPIOF_*
1405 * @label: a literal description string of this GPIO
1407 int gpio_request_one(unsigned gpio
, unsigned long flags
, const char *label
)
1411 err
= gpio_request(gpio
, label
);
1415 if (flags
& GPIOF_OPEN_DRAIN
)
1416 set_bit(FLAG_OPEN_DRAIN
, &gpio_desc
[gpio
].flags
);
1418 if (flags
& GPIOF_OPEN_SOURCE
)
1419 set_bit(FLAG_OPEN_SOURCE
, &gpio_desc
[gpio
].flags
);
1421 if (flags
& GPIOF_DIR_IN
)
1422 err
= gpio_direction_input(gpio
);
1424 err
= gpio_direction_output(gpio
,
1425 (flags
& GPIOF_INIT_HIGH
) ? 1 : 0);
1430 if (flags
& GPIOF_EXPORT
) {
1431 err
= gpio_export(gpio
, flags
& GPIOF_EXPORT_CHANGEABLE
);
1442 EXPORT_SYMBOL_GPL(gpio_request_one
);
1445 * gpio_request_array - request multiple GPIOs in a single call
1446 * @array: array of the 'struct gpio'
1447 * @num: how many GPIOs in the array
1449 int gpio_request_array(const struct gpio
*array
, size_t num
)
1453 for (i
= 0; i
< num
; i
++, array
++) {
1454 err
= gpio_request_one(array
->gpio
, array
->flags
, array
->label
);
1462 gpio_free((--array
)->gpio
);
1465 EXPORT_SYMBOL_GPL(gpio_request_array
);
1468 * gpio_free_array - release multiple GPIOs in a single call
1469 * @array: array of the 'struct gpio'
1470 * @num: how many GPIOs in the array
1472 void gpio_free_array(const struct gpio
*array
, size_t num
)
1475 gpio_free((array
++)->gpio
);
1477 EXPORT_SYMBOL_GPL(gpio_free_array
);
1480 * gpiochip_is_requested - return string iff signal was requested
1481 * @chip: controller managing the signal
1482 * @offset: of signal within controller's 0..(ngpio - 1) range
1484 * Returns NULL if the GPIO is not currently requested, else a string.
1485 * If debugfs support is enabled, the string returned is the label passed
1486 * to gpio_request(); otherwise it is a meaningless constant.
1488 * This function is for use by GPIO controller drivers. The label can
1489 * help with diagnostics, and knowing that the signal is used as a GPIO
1490 * can help avoid accidentally multiplexing it to another controller.
1492 const char *gpiochip_is_requested(struct gpio_chip
*chip
, unsigned offset
)
1494 unsigned gpio
= chip
->base
+ offset
;
1496 if (!gpio_is_valid(gpio
) || gpio_desc
[gpio
].chip
!= chip
)
1498 if (test_bit(FLAG_REQUESTED
, &gpio_desc
[gpio
].flags
) == 0)
1500 #ifdef CONFIG_DEBUG_FS
1501 return gpio_desc
[gpio
].label
;
1506 EXPORT_SYMBOL_GPL(gpiochip_is_requested
);
1509 /* Drivers MUST set GPIO direction before making get/set calls. In
1510 * some cases this is done in early boot, before IRQs are enabled.
1512 * As a rule these aren't called more than once (except for drivers
1513 * using the open-drain emulation idiom) so these are natural places
1514 * to accumulate extra debugging checks. Note that we can't (yet)
1515 * rely on gpio_request() having been called beforehand.
1518 int gpio_direction_input(unsigned gpio
)
1520 unsigned long flags
;
1521 struct gpio_chip
*chip
;
1522 struct gpio_desc
*desc
= &gpio_desc
[gpio
];
1523 int status
= -EINVAL
;
1525 spin_lock_irqsave(&gpio_lock
, flags
);
1527 if (!gpio_is_valid(gpio
))
1530 if (!chip
|| !chip
->get
|| !chip
->direction_input
)
1533 if (gpio
>= chip
->ngpio
)
1535 status
= gpio_ensure_requested(desc
, gpio
);
1539 /* now we know the gpio is valid and chip won't vanish */
1541 spin_unlock_irqrestore(&gpio_lock
, flags
);
1543 might_sleep_if(chip
->can_sleep
);
1546 status
= chip
->request(chip
, gpio
);
1548 pr_debug("GPIO-%d: chip request fail, %d\n",
1549 chip
->base
+ gpio
, status
);
1550 /* and it's not available to anyone else ...
1551 * gpio_request() is the fully clean solution.
1557 status
= chip
->direction_input(chip
, gpio
);
1559 clear_bit(FLAG_IS_OUT
, &desc
->flags
);
1561 trace_gpio_direction(chip
->base
+ gpio
, 1, status
);
1565 spin_unlock_irqrestore(&gpio_lock
, flags
);
1567 pr_debug("%s: gpio-%d status %d\n",
1568 __func__
, gpio
, status
);
1571 EXPORT_SYMBOL_GPL(gpio_direction_input
);
1573 int gpio_direction_output(unsigned gpio
, int value
)
1575 unsigned long flags
;
1576 struct gpio_chip
*chip
;
1577 struct gpio_desc
*desc
= &gpio_desc
[gpio
];
1578 int status
= -EINVAL
;
1580 /* Open drain pin should not be driven to 1 */
1581 if (value
&& test_bit(FLAG_OPEN_DRAIN
, &desc
->flags
))
1582 return gpio_direction_input(gpio
);
1584 /* Open source pin should not be driven to 0 */
1585 if (!value
&& test_bit(FLAG_OPEN_SOURCE
, &desc
->flags
))
1586 return gpio_direction_input(gpio
);
1588 spin_lock_irqsave(&gpio_lock
, flags
);
1590 if (!gpio_is_valid(gpio
))
1593 if (!chip
|| !chip
->set
|| !chip
->direction_output
)
1596 if (gpio
>= chip
->ngpio
)
1598 status
= gpio_ensure_requested(desc
, gpio
);
1602 /* now we know the gpio is valid and chip won't vanish */
1604 spin_unlock_irqrestore(&gpio_lock
, flags
);
1606 might_sleep_if(chip
->can_sleep
);
1609 status
= chip
->request(chip
, gpio
);
1611 pr_debug("GPIO-%d: chip request fail, %d\n",
1612 chip
->base
+ gpio
, status
);
1613 /* and it's not available to anyone else ...
1614 * gpio_request() is the fully clean solution.
1620 status
= chip
->direction_output(chip
, gpio
, value
);
1622 set_bit(FLAG_IS_OUT
, &desc
->flags
);
1623 trace_gpio_value(chip
->base
+ gpio
, 0, value
);
1624 trace_gpio_direction(chip
->base
+ gpio
, 0, status
);
1628 spin_unlock_irqrestore(&gpio_lock
, flags
);
1630 pr_debug("%s: gpio-%d status %d\n",
1631 __func__
, gpio
, status
);
1634 EXPORT_SYMBOL_GPL(gpio_direction_output
);
1637 * gpio_set_debounce - sets @debounce time for a @gpio
1638 * @gpio: the gpio to set debounce time
1639 * @debounce: debounce time is microseconds
1641 int gpio_set_debounce(unsigned gpio
, unsigned debounce
)
1643 unsigned long flags
;
1644 struct gpio_chip
*chip
;
1645 struct gpio_desc
*desc
= &gpio_desc
[gpio
];
1646 int status
= -EINVAL
;
1648 spin_lock_irqsave(&gpio_lock
, flags
);
1650 if (!gpio_is_valid(gpio
))
1653 if (!chip
|| !chip
->set
|| !chip
->set_debounce
)
1656 if (gpio
>= chip
->ngpio
)
1658 status
= gpio_ensure_requested(desc
, gpio
);
1662 /* now we know the gpio is valid and chip won't vanish */
1664 spin_unlock_irqrestore(&gpio_lock
, flags
);
1666 might_sleep_if(chip
->can_sleep
);
1668 return chip
->set_debounce(chip
, gpio
, debounce
);
1671 spin_unlock_irqrestore(&gpio_lock
, flags
);
1673 pr_debug("%s: gpio-%d status %d\n",
1674 __func__
, gpio
, status
);
1678 EXPORT_SYMBOL_GPL(gpio_set_debounce
);
1680 /* I/O calls are only valid after configuration completed; the relevant
1681 * "is this a valid GPIO" error checks should already have been done.
1683 * "Get" operations are often inlinable as reading a pin value register,
1684 * and masking the relevant bit in that register.
1686 * When "set" operations are inlinable, they involve writing that mask to
1687 * one register to set a low value, or a different register to set it high.
1688 * Otherwise locking is needed, so there may be little value to inlining.
1690 *------------------------------------------------------------------------
1692 * IMPORTANT!!! The hot paths -- get/set value -- assume that callers
1693 * have requested the GPIO. That can include implicit requesting by
1694 * a direction setting call. Marking a gpio as requested locks its chip
1695 * in memory, guaranteeing that these table lookups need no more locking
1696 * and that gpiochip_remove() will fail.
1698 * REVISIT when debugging, consider adding some instrumentation to ensure
1699 * that the GPIO was actually requested.
1703 * __gpio_get_value() - return a gpio's value
1704 * @gpio: gpio whose value will be returned
1707 * This is used directly or indirectly to implement gpio_get_value().
1708 * It returns the zero or nonzero value provided by the associated
1709 * gpio_chip.get() method; or zero if no such method is provided.
1711 int __gpio_get_value(unsigned gpio
)
1713 struct gpio_chip
*chip
;
1716 chip
= gpio_to_chip(gpio
);
1717 /* Should be using gpio_get_value_cansleep() */
1718 WARN_ON(chip
->can_sleep
);
1719 value
= chip
->get
? chip
->get(chip
, gpio
- chip
->base
) : 0;
1720 trace_gpio_value(gpio
, 1, value
);
1723 EXPORT_SYMBOL_GPL(__gpio_get_value
);
1726 * _gpio_set_open_drain_value() - Set the open drain gpio's value.
1727 * @gpio: Gpio whose state need to be set.
1729 * @value: Non-zero for setting it HIGH otherise it will set to LOW.
1731 static void _gpio_set_open_drain_value(unsigned gpio
,
1732 struct gpio_chip
*chip
, int value
)
1736 err
= chip
->direction_input(chip
, gpio
- chip
->base
);
1738 clear_bit(FLAG_IS_OUT
, &gpio_desc
[gpio
].flags
);
1740 err
= chip
->direction_output(chip
, gpio
- chip
->base
, 0);
1742 set_bit(FLAG_IS_OUT
, &gpio_desc
[gpio
].flags
);
1744 trace_gpio_direction(gpio
, value
, err
);
1746 pr_err("%s: Error in set_value for open drain gpio%d err %d\n",
1747 __func__
, gpio
, err
);
1751 * _gpio_set_open_source() - Set the open source gpio's value.
1752 * @gpio: Gpio whose state need to be set.
1754 * @value: Non-zero for setting it HIGH otherise it will set to LOW.
1756 static void _gpio_set_open_source_value(unsigned gpio
,
1757 struct gpio_chip
*chip
, int value
)
1761 err
= chip
->direction_output(chip
, gpio
- chip
->base
, 1);
1763 set_bit(FLAG_IS_OUT
, &gpio_desc
[gpio
].flags
);
1765 err
= chip
->direction_input(chip
, gpio
- chip
->base
);
1767 clear_bit(FLAG_IS_OUT
, &gpio_desc
[gpio
].flags
);
1769 trace_gpio_direction(gpio
, !value
, err
);
1771 pr_err("%s: Error in set_value for open source gpio%d err %d\n",
1772 __func__
, gpio
, err
);
1777 * __gpio_set_value() - assign a gpio's value
1778 * @gpio: gpio whose value will be assigned
1779 * @value: value to assign
1782 * This is used directly or indirectly to implement gpio_set_value().
1783 * It invokes the associated gpio_chip.set() method.
1785 void __gpio_set_value(unsigned gpio
, int value
)
1787 struct gpio_chip
*chip
;
1789 chip
= gpio_to_chip(gpio
);
1790 /* Should be using gpio_set_value_cansleep() */
1791 WARN_ON(chip
->can_sleep
);
1792 trace_gpio_value(gpio
, 0, value
);
1793 if (test_bit(FLAG_OPEN_DRAIN
, &gpio_desc
[gpio
].flags
))
1794 _gpio_set_open_drain_value(gpio
, chip
, value
);
1795 else if (test_bit(FLAG_OPEN_SOURCE
, &gpio_desc
[gpio
].flags
))
1796 _gpio_set_open_source_value(gpio
, chip
, value
);
1798 chip
->set(chip
, gpio
- chip
->base
, value
);
1800 EXPORT_SYMBOL_GPL(__gpio_set_value
);
1803 * __gpio_cansleep() - report whether gpio value access will sleep
1804 * @gpio: gpio in question
1807 * This is used directly or indirectly to implement gpio_cansleep(). It
1808 * returns nonzero if access reading or writing the GPIO value can sleep.
1810 int __gpio_cansleep(unsigned gpio
)
1812 struct gpio_chip
*chip
;
1814 /* only call this on GPIOs that are valid! */
1815 chip
= gpio_to_chip(gpio
);
1817 return chip
->can_sleep
;
1819 EXPORT_SYMBOL_GPL(__gpio_cansleep
);
1822 * __gpio_to_irq() - return the IRQ corresponding to a GPIO
1823 * @gpio: gpio whose IRQ will be returned (already requested)
1826 * This is used directly or indirectly to implement gpio_to_irq().
1827 * It returns the number of the IRQ signaled by this (input) GPIO,
1828 * or a negative errno.
1830 int __gpio_to_irq(unsigned gpio
)
1832 struct gpio_chip
*chip
;
1834 chip
= gpio_to_chip(gpio
);
1835 return chip
->to_irq
? chip
->to_irq(chip
, gpio
- chip
->base
) : -ENXIO
;
1837 EXPORT_SYMBOL_GPL(__gpio_to_irq
);
1841 /* There's no value in making it easy to inline GPIO calls that may sleep.
1842 * Common examples include ones connected to I2C or SPI chips.
1845 int gpio_get_value_cansleep(unsigned gpio
)
1847 struct gpio_chip
*chip
;
1850 might_sleep_if(extra_checks
);
1851 chip
= gpio_to_chip(gpio
);
1852 value
= chip
->get
? chip
->get(chip
, gpio
- chip
->base
) : 0;
1853 trace_gpio_value(gpio
, 1, value
);
1856 EXPORT_SYMBOL_GPL(gpio_get_value_cansleep
);
1858 void gpio_set_value_cansleep(unsigned gpio
, int value
)
1860 struct gpio_chip
*chip
;
1862 might_sleep_if(extra_checks
);
1863 chip
= gpio_to_chip(gpio
);
1864 trace_gpio_value(gpio
, 0, value
);
1865 if (test_bit(FLAG_OPEN_DRAIN
, &gpio_desc
[gpio
].flags
))
1866 _gpio_set_open_drain_value(gpio
, chip
, value
);
1867 else if (test_bit(FLAG_OPEN_SOURCE
, &gpio_desc
[gpio
].flags
))
1868 _gpio_set_open_source_value(gpio
, chip
, value
);
1870 chip
->set(chip
, gpio
- chip
->base
, value
);
1872 EXPORT_SYMBOL_GPL(gpio_set_value_cansleep
);
1875 #ifdef CONFIG_DEBUG_FS
1877 static void gpiolib_dbg_show(struct seq_file
*s
, struct gpio_chip
*chip
)
1880 unsigned gpio
= chip
->base
;
1881 struct gpio_desc
*gdesc
= &gpio_desc
[gpio
];
1884 for (i
= 0; i
< chip
->ngpio
; i
++, gpio
++, gdesc
++) {
1885 if (!test_bit(FLAG_REQUESTED
, &gdesc
->flags
))
1888 gpio_get_direction(gpio
);
1889 is_out
= test_bit(FLAG_IS_OUT
, &gdesc
->flags
);
1890 seq_printf(s
, " gpio-%-3d (%-20.20s) %s %s",
1892 is_out
? "out" : "in ",
1894 ? (chip
->get(chip
, i
) ? "hi" : "lo")
1896 seq_printf(s
, "\n");
1900 static void *gpiolib_seq_start(struct seq_file
*s
, loff_t
*pos
)
1902 struct gpio_chip
*chip
= NULL
;
1907 /* REVISIT this isn't locked against gpio_chip removal ... */
1909 for (gpio
= 0; gpio_is_valid(gpio
); gpio
++) {
1910 if (gpio_desc
[gpio
].chip
== chip
)
1913 chip
= gpio_desc
[gpio
].chip
;
1917 if (index
++ >= *pos
) {
1928 static void *gpiolib_seq_next(struct seq_file
*s
, void *v
, loff_t
*pos
)
1930 struct gpio_chip
*chip
= v
;
1934 /* skip GPIOs provided by the current chip */
1935 for (gpio
= chip
->base
+ chip
->ngpio
; gpio_is_valid(gpio
); gpio
++) {
1936 chip
= gpio_desc
[gpio
].chip
;
1949 static void gpiolib_seq_stop(struct seq_file
*s
, void *v
)
1953 static int gpiolib_seq_show(struct seq_file
*s
, void *v
)
1955 struct gpio_chip
*chip
= v
;
1958 seq_printf(s
, "%sGPIOs %d-%d", (char *)s
->private,
1959 chip
->base
, chip
->base
+ chip
->ngpio
- 1);
1962 seq_printf(s
, ", %s/%s", dev
->bus
? dev
->bus
->name
: "no-bus",
1965 seq_printf(s
, ", %s", chip
->label
);
1966 if (chip
->can_sleep
)
1967 seq_printf(s
, ", can sleep");
1968 seq_printf(s
, ":\n");
1971 chip
->dbg_show(s
, chip
);
1973 gpiolib_dbg_show(s
, chip
);
1978 static const struct seq_operations gpiolib_seq_ops
= {
1979 .start
= gpiolib_seq_start
,
1980 .next
= gpiolib_seq_next
,
1981 .stop
= gpiolib_seq_stop
,
1982 .show
= gpiolib_seq_show
,
1985 static int gpiolib_open(struct inode
*inode
, struct file
*file
)
1987 return seq_open(file
, &gpiolib_seq_ops
);
1990 static const struct file_operations gpiolib_operations
= {
1991 .owner
= THIS_MODULE
,
1992 .open
= gpiolib_open
,
1994 .llseek
= seq_lseek
,
1995 .release
= seq_release
,
1998 static int __init
gpiolib_debugfs_init(void)
2000 /* /sys/kernel/debug/gpio */
2001 (void) debugfs_create_file("gpio", S_IFREG
| S_IRUGO
,
2002 NULL
, NULL
, &gpiolib_operations
);
2005 subsys_initcall(gpiolib_debugfs_init
);
2007 #endif /* DEBUG_FS */