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>
16 /* Optional implementation infrastructure for GPIO interfaces.
18 * Platforms may want to use this if they tend to use very many GPIOs
19 * that aren't part of a System-On-Chip core; or across I2C/SPI/etc.
21 * When kernel footprint or instruction count is an issue, simpler
22 * implementations may be preferred. The GPIO programming interface
23 * allows for inlining speed-critical get/set operations for common
24 * cases, so that access to SOC-integrated GPIOs can sometimes cost
25 * only an instruction or two per bit.
29 /* When debugging, extend minimal trust to callers and platform code.
30 * Also emit diagnostic messages that may help initial bringup, when
31 * board setup or driver bugs are most common.
33 * Otherwise, minimize overhead in what may be bitbanging codepaths.
36 #define extra_checks 1
38 #define extra_checks 0
41 /* gpio_lock prevents conflicts during gpio_desc[] table updates.
42 * While any GPIO is requested, its gpio_chip is not removable;
43 * each GPIO's "requested" flag serves as a lock and refcount.
45 static DEFINE_SPINLOCK(gpio_lock
);
48 struct gpio_chip
*chip
;
50 /* flag symbols are bit numbers */
51 #define FLAG_REQUESTED 0
53 #define FLAG_RESERVED 2
54 #define FLAG_EXPORT 3 /* protected by sysfs_lock */
55 #define FLAG_SYSFS 4 /* exported via /sys/class/gpio/control */
56 #define FLAG_TRIG_FALL 5 /* trigger on falling edge */
57 #define FLAG_TRIG_RISE 6 /* trigger on rising edge */
58 #define FLAG_ACTIVE_LOW 7 /* sysfs value has active low */
60 #define PDESC_ID_SHIFT 16 /* add new flags before this one */
62 #define GPIO_FLAGS_MASK ((1 << PDESC_ID_SHIFT) - 1)
63 #define GPIO_TRIGGER_MASK (BIT(FLAG_TRIG_FALL) | BIT(FLAG_TRIG_RISE))
65 #ifdef CONFIG_DEBUG_FS
69 static struct gpio_desc gpio_desc
[ARCH_NR_GPIOS
];
71 #ifdef CONFIG_GPIO_SYSFS
73 struct work_struct work
;
74 struct sysfs_dirent
*value_sd
;
77 static struct idr pdesc_idr
;
80 static inline void desc_set_label(struct gpio_desc
*d
, const char *label
)
82 #ifdef CONFIG_DEBUG_FS
87 /* Warn when drivers omit gpio_request() calls -- legal but ill-advised
88 * when setting direction, and otherwise illegal. Until board setup code
89 * and drivers use explicit requests everywhere (which won't happen when
90 * those calls have no teeth) we can't avoid autorequesting. This nag
91 * message should motivate switching to explicit requests... so should
92 * the weaker cleanup after faults, compared to gpio_request().
94 * NOTE: the autorequest mechanism is going away; at this point it's
95 * only "legal" in the sense that (old) code using it won't break yet,
96 * but instead only triggers a WARN() stack dump.
98 static int gpio_ensure_requested(struct gpio_desc
*desc
, unsigned offset
)
100 const struct gpio_chip
*chip
= desc
->chip
;
101 const int gpio
= chip
->base
+ offset
;
103 if (WARN(test_and_set_bit(FLAG_REQUESTED
, &desc
->flags
) == 0,
104 "autorequest GPIO-%d\n", gpio
)) {
105 if (!try_module_get(chip
->owner
)) {
106 pr_err("GPIO-%d: module can't be gotten \n", gpio
);
107 clear_bit(FLAG_REQUESTED
, &desc
->flags
);
111 desc_set_label(desc
, "[auto]");
112 /* caller must chip->request() w/o spinlock */
119 /* caller holds gpio_lock *OR* gpio is marked as requested */
120 static inline struct gpio_chip
*gpio_to_chip(unsigned gpio
)
122 return gpio_desc
[gpio
].chip
;
125 /* dynamic allocation of GPIOs, e.g. on a hotplugged device */
126 static int gpiochip_find_base(int ngpio
)
132 for (i
= ARCH_NR_GPIOS
- 1; i
>= 0 ; i
--) {
133 struct gpio_desc
*desc
= &gpio_desc
[i
];
134 struct gpio_chip
*chip
= desc
->chip
;
136 if (!chip
&& !test_bit(FLAG_RESERVED
, &desc
->flags
)) {
138 if (spare
== ngpio
) {
145 i
-= chip
->ngpio
- 1;
149 if (gpio_is_valid(base
))
150 pr_debug("%s: found new base at %d\n", __func__
, base
);
155 * gpiochip_reserve() - reserve range of gpios to use with platform code only
156 * @start: starting gpio number
157 * @ngpio: number of gpios to reserve
158 * Context: platform init, potentially before irqs or kmalloc will work
160 * Returns a negative errno if any gpio within the range is already reserved
161 * or registered, else returns zero as a success code. Use this function
162 * to mark a range of gpios as unavailable for dynamic gpio number allocation,
163 * for example because its driver support is not yet loaded.
165 int __init
gpiochip_reserve(int start
, int ngpio
)
171 if (!gpio_is_valid(start
) || !gpio_is_valid(start
+ ngpio
- 1))
174 spin_lock_irqsave(&gpio_lock
, flags
);
176 for (i
= start
; i
< start
+ ngpio
; i
++) {
177 struct gpio_desc
*desc
= &gpio_desc
[i
];
179 if (desc
->chip
|| test_bit(FLAG_RESERVED
, &desc
->flags
)) {
184 set_bit(FLAG_RESERVED
, &desc
->flags
);
187 pr_debug("%s: reserved gpios from %d to %d\n",
188 __func__
, start
, start
+ ngpio
- 1);
190 spin_unlock_irqrestore(&gpio_lock
, flags
);
195 #ifdef CONFIG_GPIO_SYSFS
197 /* lock protects against unexport_gpio() being called while
198 * sysfs files are active.
200 static DEFINE_MUTEX(sysfs_lock
);
203 * /sys/class/gpio/gpioN... only for GPIOs that are exported
205 * * MAY BE OMITTED if kernel won't allow direction changes
206 * * is read/write as "in" or "out"
207 * * may also be written as "high" or "low", initializing
208 * output value as specified ("out" implies "low")
210 * * always readable, subject to hardware behavior
211 * * may be writable, as zero/nonzero
213 * * configures behavior of poll(2) on /value
214 * * available only if pin can generate IRQs on input
215 * * is read/write as "none", "falling", "rising", or "both"
217 * * configures polarity of /value
218 * * is read/write as zero/nonzero
219 * * also affects existing and subsequent "falling" and "rising"
220 * /edge configuration
223 static ssize_t
gpio_direction_show(struct device
*dev
,
224 struct device_attribute
*attr
, char *buf
)
226 const struct gpio_desc
*desc
= dev_get_drvdata(dev
);
229 mutex_lock(&sysfs_lock
);
231 if (!test_bit(FLAG_EXPORT
, &desc
->flags
))
234 status
= sprintf(buf
, "%s\n",
235 test_bit(FLAG_IS_OUT
, &desc
->flags
)
238 mutex_unlock(&sysfs_lock
);
242 static ssize_t
gpio_direction_store(struct device
*dev
,
243 struct device_attribute
*attr
, const char *buf
, size_t size
)
245 const struct gpio_desc
*desc
= dev_get_drvdata(dev
);
246 unsigned gpio
= desc
- gpio_desc
;
249 mutex_lock(&sysfs_lock
);
251 if (!test_bit(FLAG_EXPORT
, &desc
->flags
))
253 else if (sysfs_streq(buf
, "high"))
254 status
= gpio_direction_output(gpio
, 1);
255 else if (sysfs_streq(buf
, "out") || sysfs_streq(buf
, "low"))
256 status
= gpio_direction_output(gpio
, 0);
257 else if (sysfs_streq(buf
, "in"))
258 status
= gpio_direction_input(gpio
);
262 mutex_unlock(&sysfs_lock
);
263 return status
? : size
;
266 static /* const */ DEVICE_ATTR(direction
, 0644,
267 gpio_direction_show
, gpio_direction_store
);
269 static ssize_t
gpio_value_show(struct device
*dev
,
270 struct device_attribute
*attr
, char *buf
)
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
)) {
283 value
= !!gpio_get_value_cansleep(gpio
);
284 if (test_bit(FLAG_ACTIVE_LOW
, &desc
->flags
))
287 status
= sprintf(buf
, "%d\n", value
);
290 mutex_unlock(&sysfs_lock
);
294 static ssize_t
gpio_value_store(struct device
*dev
,
295 struct device_attribute
*attr
, const char *buf
, size_t size
)
297 const struct gpio_desc
*desc
= dev_get_drvdata(dev
);
298 unsigned gpio
= desc
- gpio_desc
;
301 mutex_lock(&sysfs_lock
);
303 if (!test_bit(FLAG_EXPORT
, &desc
->flags
))
305 else if (!test_bit(FLAG_IS_OUT
, &desc
->flags
))
310 status
= strict_strtol(buf
, 0, &value
);
312 if (test_bit(FLAG_ACTIVE_LOW
, &desc
->flags
))
314 gpio_set_value_cansleep(gpio
, value
!= 0);
319 mutex_unlock(&sysfs_lock
);
323 static const DEVICE_ATTR(value
, 0644,
324 gpio_value_show
, gpio_value_store
);
326 static irqreturn_t
gpio_sysfs_irq(int irq
, void *priv
)
328 struct work_struct
*work
= priv
;
334 static void gpio_notify_sysfs(struct work_struct
*work
)
336 struct poll_desc
*pdesc
;
338 pdesc
= container_of(work
, struct poll_desc
, work
);
339 sysfs_notify_dirent(pdesc
->value_sd
);
342 static int gpio_setup_irq(struct gpio_desc
*desc
, struct device
*dev
,
343 unsigned long gpio_flags
)
345 struct poll_desc
*pdesc
;
346 unsigned long irq_flags
;
349 if ((desc
->flags
& GPIO_TRIGGER_MASK
) == gpio_flags
)
352 irq
= gpio_to_irq(desc
- gpio_desc
);
356 id
= desc
->flags
>> PDESC_ID_SHIFT
;
357 pdesc
= idr_find(&pdesc_idr
, id
);
359 free_irq(irq
, &pdesc
->work
);
360 cancel_work_sync(&pdesc
->work
);
363 desc
->flags
&= ~GPIO_TRIGGER_MASK
;
370 irq_flags
= IRQF_SHARED
;
371 if (test_bit(FLAG_TRIG_FALL
, &gpio_flags
))
372 irq_flags
|= test_bit(FLAG_ACTIVE_LOW
, &desc
->flags
) ?
373 IRQF_TRIGGER_RISING
: IRQF_TRIGGER_FALLING
;
374 if (test_bit(FLAG_TRIG_RISE
, &gpio_flags
))
375 irq_flags
|= test_bit(FLAG_ACTIVE_LOW
, &desc
->flags
) ?
376 IRQF_TRIGGER_FALLING
: IRQF_TRIGGER_RISING
;
379 pdesc
= kmalloc(sizeof(*pdesc
), GFP_KERNEL
);
387 if (idr_pre_get(&pdesc_idr
, GFP_KERNEL
))
388 ret
= idr_get_new_above(&pdesc_idr
,
390 } while (ret
== -EAGAIN
);
395 desc
->flags
&= GPIO_FLAGS_MASK
;
396 desc
->flags
|= (unsigned long)id
<< PDESC_ID_SHIFT
;
398 if (desc
->flags
>> PDESC_ID_SHIFT
!= id
) {
403 pdesc
->value_sd
= sysfs_get_dirent(dev
->kobj
.sd
, NULL
, "value");
404 if (!pdesc
->value_sd
) {
408 INIT_WORK(&pdesc
->work
, gpio_notify_sysfs
);
411 ret
= request_irq(irq
, gpio_sysfs_irq
, irq_flags
,
412 "gpiolib", &pdesc
->work
);
416 desc
->flags
|= gpio_flags
;
421 sysfs_put(pdesc
->value_sd
);
423 idr_remove(&pdesc_idr
, id
);
424 desc
->flags
&= GPIO_FLAGS_MASK
;
431 static const struct {
434 } trigger_types
[] = {
436 { "falling", BIT(FLAG_TRIG_FALL
) },
437 { "rising", BIT(FLAG_TRIG_RISE
) },
438 { "both", BIT(FLAG_TRIG_FALL
) | BIT(FLAG_TRIG_RISE
) },
441 static ssize_t
gpio_edge_show(struct device
*dev
,
442 struct device_attribute
*attr
, char *buf
)
444 const struct gpio_desc
*desc
= dev_get_drvdata(dev
);
447 mutex_lock(&sysfs_lock
);
449 if (!test_bit(FLAG_EXPORT
, &desc
->flags
))
455 for (i
= 0; i
< ARRAY_SIZE(trigger_types
); i
++)
456 if ((desc
->flags
& GPIO_TRIGGER_MASK
)
457 == trigger_types
[i
].flags
) {
458 status
= sprintf(buf
, "%s\n",
459 trigger_types
[i
].name
);
464 mutex_unlock(&sysfs_lock
);
468 static ssize_t
gpio_edge_store(struct device
*dev
,
469 struct device_attribute
*attr
, const char *buf
, size_t size
)
471 struct gpio_desc
*desc
= dev_get_drvdata(dev
);
475 for (i
= 0; i
< ARRAY_SIZE(trigger_types
); i
++)
476 if (sysfs_streq(trigger_types
[i
].name
, buf
))
481 mutex_lock(&sysfs_lock
);
483 if (!test_bit(FLAG_EXPORT
, &desc
->flags
))
486 status
= gpio_setup_irq(desc
, dev
, trigger_types
[i
].flags
);
491 mutex_unlock(&sysfs_lock
);
496 static DEVICE_ATTR(edge
, 0644, gpio_edge_show
, gpio_edge_store
);
498 static int sysfs_set_active_low(struct gpio_desc
*desc
, struct device
*dev
,
503 if (!!test_bit(FLAG_ACTIVE_LOW
, &desc
->flags
) == !!value
)
507 set_bit(FLAG_ACTIVE_LOW
, &desc
->flags
);
509 clear_bit(FLAG_ACTIVE_LOW
, &desc
->flags
);
511 /* reconfigure poll(2) support if enabled on one edge only */
512 if (dev
!= NULL
&& (!!test_bit(FLAG_TRIG_RISE
, &desc
->flags
) ^
513 !!test_bit(FLAG_TRIG_FALL
, &desc
->flags
))) {
514 unsigned long trigger_flags
= desc
->flags
& GPIO_TRIGGER_MASK
;
516 gpio_setup_irq(desc
, dev
, 0);
517 status
= gpio_setup_irq(desc
, dev
, trigger_flags
);
523 static ssize_t
gpio_active_low_show(struct device
*dev
,
524 struct device_attribute
*attr
, char *buf
)
526 const struct gpio_desc
*desc
= dev_get_drvdata(dev
);
529 mutex_lock(&sysfs_lock
);
531 if (!test_bit(FLAG_EXPORT
, &desc
->flags
))
534 status
= sprintf(buf
, "%d\n",
535 !!test_bit(FLAG_ACTIVE_LOW
, &desc
->flags
));
537 mutex_unlock(&sysfs_lock
);
542 static ssize_t
gpio_active_low_store(struct device
*dev
,
543 struct device_attribute
*attr
, const char *buf
, size_t size
)
545 struct gpio_desc
*desc
= dev_get_drvdata(dev
);
548 mutex_lock(&sysfs_lock
);
550 if (!test_bit(FLAG_EXPORT
, &desc
->flags
)) {
555 status
= strict_strtol(buf
, 0, &value
);
557 status
= sysfs_set_active_low(desc
, dev
, value
!= 0);
560 mutex_unlock(&sysfs_lock
);
562 return status
? : size
;
565 static const DEVICE_ATTR(active_low
, 0644,
566 gpio_active_low_show
, gpio_active_low_store
);
568 static const struct attribute
*gpio_attrs
[] = {
569 &dev_attr_value
.attr
,
570 &dev_attr_active_low
.attr
,
574 static const struct attribute_group gpio_attr_group
= {
575 .attrs
= (struct attribute
**) gpio_attrs
,
579 * /sys/class/gpio/gpiochipN/
580 * /base ... matching gpio_chip.base (N)
581 * /label ... matching gpio_chip.label
582 * /ngpio ... matching gpio_chip.ngpio
585 static ssize_t
chip_base_show(struct device
*dev
,
586 struct device_attribute
*attr
, char *buf
)
588 const struct gpio_chip
*chip
= dev_get_drvdata(dev
);
590 return sprintf(buf
, "%d\n", chip
->base
);
592 static DEVICE_ATTR(base
, 0444, chip_base_show
, NULL
);
594 static ssize_t
chip_label_show(struct device
*dev
,
595 struct device_attribute
*attr
, char *buf
)
597 const struct gpio_chip
*chip
= dev_get_drvdata(dev
);
599 return sprintf(buf
, "%s\n", chip
->label
? : "");
601 static DEVICE_ATTR(label
, 0444, chip_label_show
, NULL
);
603 static ssize_t
chip_ngpio_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
, "%u\n", chip
->ngpio
);
610 static DEVICE_ATTR(ngpio
, 0444, chip_ngpio_show
, NULL
);
612 static const struct attribute
*gpiochip_attrs
[] = {
614 &dev_attr_label
.attr
,
615 &dev_attr_ngpio
.attr
,
619 static const struct attribute_group gpiochip_attr_group
= {
620 .attrs
= (struct attribute
**) gpiochip_attrs
,
624 * /sys/class/gpio/export ... write-only
625 * integer N ... number of GPIO to export (full access)
626 * /sys/class/gpio/unexport ... write-only
627 * integer N ... number of GPIO to unexport
629 static ssize_t
export_store(struct class *class,
630 struct class_attribute
*attr
,
631 const char *buf
, size_t len
)
636 status
= strict_strtol(buf
, 0, &gpio
);
640 /* No extra locking here; FLAG_SYSFS just signifies that the
641 * request and export were done by on behalf of userspace, so
642 * they may be undone on its behalf too.
645 status
= gpio_request(gpio
, "sysfs");
649 status
= gpio_export(gpio
, true);
653 set_bit(FLAG_SYSFS
, &gpio_desc
[gpio
].flags
);
657 pr_debug("%s: status %d\n", __func__
, status
);
658 return status
? : len
;
661 static ssize_t
unexport_store(struct class *class,
662 struct class_attribute
*attr
,
663 const char *buf
, size_t len
)
668 status
= strict_strtol(buf
, 0, &gpio
);
674 /* reject bogus commands (gpio_unexport ignores them) */
675 if (!gpio_is_valid(gpio
))
678 /* No extra locking here; FLAG_SYSFS just signifies that the
679 * request and export were done by on behalf of userspace, so
680 * they may be undone on its behalf too.
682 if (test_and_clear_bit(FLAG_SYSFS
, &gpio_desc
[gpio
].flags
)) {
688 pr_debug("%s: status %d\n", __func__
, status
);
689 return status
? : len
;
692 static struct class_attribute gpio_class_attrs
[] = {
693 __ATTR(export
, 0200, NULL
, export_store
),
694 __ATTR(unexport
, 0200, NULL
, unexport_store
),
698 static struct class gpio_class
= {
700 .owner
= THIS_MODULE
,
702 .class_attrs
= gpio_class_attrs
,
707 * gpio_export - export a GPIO through sysfs
708 * @gpio: gpio to make available, already requested
709 * @direction_may_change: true if userspace may change gpio direction
710 * Context: arch_initcall or later
712 * When drivers want to make a GPIO accessible to userspace after they
713 * have requested it -- perhaps while debugging, or as part of their
714 * public interface -- they may use this routine. If the GPIO can
715 * change direction (some can't) and the caller allows it, userspace
716 * will see "direction" sysfs attribute which may be used to change
717 * the gpio's direction. A "value" attribute will always be provided.
719 * Returns zero on success, else an error.
721 int gpio_export(unsigned gpio
, bool direction_may_change
)
724 struct gpio_desc
*desc
;
725 int status
= -EINVAL
;
726 const char *ioname
= NULL
;
728 /* can't export until sysfs is available ... */
730 pr_debug("%s: called too early!\n", __func__
);
734 if (!gpio_is_valid(gpio
))
737 mutex_lock(&sysfs_lock
);
739 spin_lock_irqsave(&gpio_lock
, flags
);
740 desc
= &gpio_desc
[gpio
];
741 if (test_bit(FLAG_REQUESTED
, &desc
->flags
)
742 && !test_bit(FLAG_EXPORT
, &desc
->flags
)) {
744 if (!desc
->chip
->direction_input
745 || !desc
->chip
->direction_output
)
746 direction_may_change
= false;
748 spin_unlock_irqrestore(&gpio_lock
, flags
);
750 if (desc
->chip
->names
&& desc
->chip
->names
[gpio
- desc
->chip
->base
])
751 ioname
= desc
->chip
->names
[gpio
- desc
->chip
->base
];
756 dev
= device_create(&gpio_class
, desc
->chip
->dev
, MKDEV(0, 0),
757 desc
, ioname
? ioname
: "gpio%u", gpio
);
759 status
= sysfs_create_group(&dev
->kobj
,
762 if (!status
&& direction_may_change
)
763 status
= device_create_file(dev
,
764 &dev_attr_direction
);
766 if (!status
&& gpio_to_irq(gpio
) >= 0
767 && (direction_may_change
768 || !test_bit(FLAG_IS_OUT
,
770 status
= device_create_file(dev
,
774 device_unregister(dev
);
776 status
= PTR_ERR(dev
);
778 set_bit(FLAG_EXPORT
, &desc
->flags
);
781 mutex_unlock(&sysfs_lock
);
785 pr_debug("%s: gpio%d status %d\n", __func__
, gpio
, status
);
789 EXPORT_SYMBOL_GPL(gpio_export
);
791 static int match_export(struct device
*dev
, void *data
)
793 return dev_get_drvdata(dev
) == data
;
797 * gpio_export_link - create a sysfs link to an exported GPIO node
798 * @dev: device under which to create symlink
799 * @name: name of the symlink
800 * @gpio: gpio to create symlink to, already exported
802 * Set up a symlink from /sys/.../dev/name to /sys/class/gpio/gpioN
803 * node. Caller is responsible for unlinking.
805 * Returns zero on success, else an error.
807 int gpio_export_link(struct device
*dev
, const char *name
, unsigned gpio
)
809 struct gpio_desc
*desc
;
810 int status
= -EINVAL
;
812 if (!gpio_is_valid(gpio
))
815 mutex_lock(&sysfs_lock
);
817 desc
= &gpio_desc
[gpio
];
819 if (test_bit(FLAG_EXPORT
, &desc
->flags
)) {
822 tdev
= class_find_device(&gpio_class
, NULL
, desc
, match_export
);
824 status
= sysfs_create_link(&dev
->kobj
, &tdev
->kobj
,
831 mutex_unlock(&sysfs_lock
);
835 pr_debug("%s: gpio%d status %d\n", __func__
, gpio
, status
);
839 EXPORT_SYMBOL_GPL(gpio_export_link
);
843 * gpio_sysfs_set_active_low - set the polarity of gpio sysfs value
844 * @gpio: gpio to change
845 * @value: non-zero to use active low, i.e. inverted values
847 * Set the polarity of /sys/class/gpio/gpioN/value sysfs attribute.
848 * The GPIO does not have to be exported yet. If poll(2) support has
849 * been enabled for either rising or falling edge, it will be
850 * reconfigured to follow the new polarity.
852 * Returns zero on success, else an error.
854 int gpio_sysfs_set_active_low(unsigned gpio
, int value
)
856 struct gpio_desc
*desc
;
857 struct device
*dev
= NULL
;
858 int status
= -EINVAL
;
860 if (!gpio_is_valid(gpio
))
863 mutex_lock(&sysfs_lock
);
865 desc
= &gpio_desc
[gpio
];
867 if (test_bit(FLAG_EXPORT
, &desc
->flags
)) {
868 dev
= class_find_device(&gpio_class
, NULL
, desc
, match_export
);
875 status
= sysfs_set_active_low(desc
, dev
, value
);
878 mutex_unlock(&sysfs_lock
);
882 pr_debug("%s: gpio%d status %d\n", __func__
, gpio
, status
);
886 EXPORT_SYMBOL_GPL(gpio_sysfs_set_active_low
);
889 * gpio_unexport - reverse effect of gpio_export()
890 * @gpio: gpio to make unavailable
892 * This is implicit on gpio_free().
894 void gpio_unexport(unsigned gpio
)
896 struct gpio_desc
*desc
;
899 if (!gpio_is_valid(gpio
)) {
904 mutex_lock(&sysfs_lock
);
906 desc
= &gpio_desc
[gpio
];
908 if (test_bit(FLAG_EXPORT
, &desc
->flags
)) {
909 struct device
*dev
= NULL
;
911 dev
= class_find_device(&gpio_class
, NULL
, desc
, match_export
);
913 gpio_setup_irq(desc
, dev
, 0);
914 clear_bit(FLAG_EXPORT
, &desc
->flags
);
916 device_unregister(dev
);
921 mutex_unlock(&sysfs_lock
);
924 pr_debug("%s: gpio%d status %d\n", __func__
, gpio
, status
);
926 EXPORT_SYMBOL_GPL(gpio_unexport
);
928 static int gpiochip_export(struct gpio_chip
*chip
)
933 /* Many systems register gpio chips for SOC support very early,
934 * before driver model support is available. In those cases we
935 * export this later, in gpiolib_sysfs_init() ... here we just
936 * verify that _some_ field of gpio_class got initialized.
941 /* use chip->base for the ID; it's already known to be unique */
942 mutex_lock(&sysfs_lock
);
943 dev
= device_create(&gpio_class
, chip
->dev
, MKDEV(0, 0), chip
,
944 "gpiochip%d", chip
->base
);
946 status
= sysfs_create_group(&dev
->kobj
,
947 &gpiochip_attr_group
);
949 status
= PTR_ERR(dev
);
950 chip
->exported
= (status
== 0);
951 mutex_unlock(&sysfs_lock
);
957 spin_lock_irqsave(&gpio_lock
, flags
);
959 while (gpio_desc
[gpio
].chip
== chip
)
960 gpio_desc
[gpio
++].chip
= NULL
;
961 spin_unlock_irqrestore(&gpio_lock
, flags
);
963 pr_debug("%s: chip %s status %d\n", __func__
,
964 chip
->label
, status
);
970 static void gpiochip_unexport(struct gpio_chip
*chip
)
975 mutex_lock(&sysfs_lock
);
976 dev
= class_find_device(&gpio_class
, NULL
, chip
, match_export
);
979 device_unregister(dev
);
984 mutex_unlock(&sysfs_lock
);
987 pr_debug("%s: chip %s status %d\n", __func__
,
988 chip
->label
, status
);
991 static int __init
gpiolib_sysfs_init(void)
997 idr_init(&pdesc_idr
);
999 status
= class_register(&gpio_class
);
1003 /* Scan and register the gpio_chips which registered very
1004 * early (e.g. before the class_register above was called).
1006 * We run before arch_initcall() so chip->dev nodes can have
1007 * registered, and so arch_initcall() can always gpio_export().
1009 spin_lock_irqsave(&gpio_lock
, flags
);
1010 for (gpio
= 0; gpio
< ARCH_NR_GPIOS
; gpio
++) {
1011 struct gpio_chip
*chip
;
1013 chip
= gpio_desc
[gpio
].chip
;
1014 if (!chip
|| chip
->exported
)
1017 spin_unlock_irqrestore(&gpio_lock
, flags
);
1018 status
= gpiochip_export(chip
);
1019 spin_lock_irqsave(&gpio_lock
, flags
);
1021 spin_unlock_irqrestore(&gpio_lock
, flags
);
1026 postcore_initcall(gpiolib_sysfs_init
);
1029 static inline int gpiochip_export(struct gpio_chip
*chip
)
1034 static inline void gpiochip_unexport(struct gpio_chip
*chip
)
1038 #endif /* CONFIG_GPIO_SYSFS */
1041 * gpiochip_add() - register a gpio_chip
1042 * @chip: the chip to register, with chip->base initialized
1043 * Context: potentially before irqs or kmalloc will work
1045 * Returns a negative errno if the chip can't be registered, such as
1046 * because the chip->base is invalid or already associated with a
1047 * different chip. Otherwise it returns zero as a success code.
1049 * When gpiochip_add() is called very early during boot, so that GPIOs
1050 * can be freely used, the chip->dev device must be registered before
1051 * the gpio framework's arch_initcall(). Otherwise sysfs initialization
1052 * for GPIOs will fail rudely.
1054 * If chip->base is negative, this requests dynamic assignment of
1055 * a range of valid GPIOs.
1057 int gpiochip_add(struct gpio_chip
*chip
)
1059 unsigned long flags
;
1062 int base
= chip
->base
;
1064 if ((!gpio_is_valid(base
) || !gpio_is_valid(base
+ chip
->ngpio
- 1))
1070 spin_lock_irqsave(&gpio_lock
, flags
);
1073 base
= gpiochip_find_base(chip
->ngpio
);
1081 /* these GPIO numbers must not be managed by another gpio_chip */
1082 for (id
= base
; id
< base
+ chip
->ngpio
; id
++) {
1083 if (gpio_desc
[id
].chip
!= NULL
) {
1089 for (id
= base
; id
< base
+ chip
->ngpio
; id
++) {
1090 gpio_desc
[id
].chip
= chip
;
1092 /* REVISIT: most hardware initializes GPIOs as
1093 * inputs (often with pullups enabled) so power
1094 * usage is minimized. Linux code should set the
1095 * gpio direction first thing; but until it does,
1096 * we may expose the wrong direction in sysfs.
1098 gpio_desc
[id
].flags
= !chip
->direction_input
1099 ? (1 << FLAG_IS_OUT
)
1104 of_gpiochip_add(chip
);
1107 spin_unlock_irqrestore(&gpio_lock
, flags
);
1112 status
= gpiochip_export(chip
);
1118 /* failures here can mean systems won't boot... */
1119 pr_err("gpiochip_add: gpios %d..%d (%s) failed to register\n",
1120 chip
->base
, chip
->base
+ chip
->ngpio
- 1,
1121 chip
->label
? : "generic");
1124 EXPORT_SYMBOL_GPL(gpiochip_add
);
1127 * gpiochip_remove() - unregister a gpio_chip
1128 * @chip: the chip to unregister
1130 * A gpio_chip with any GPIOs still requested may not be removed.
1132 int gpiochip_remove(struct gpio_chip
*chip
)
1134 unsigned long flags
;
1138 spin_lock_irqsave(&gpio_lock
, flags
);
1140 of_gpiochip_remove(chip
);
1142 for (id
= chip
->base
; id
< chip
->base
+ chip
->ngpio
; id
++) {
1143 if (test_bit(FLAG_REQUESTED
, &gpio_desc
[id
].flags
)) {
1149 for (id
= chip
->base
; id
< chip
->base
+ chip
->ngpio
; id
++)
1150 gpio_desc
[id
].chip
= NULL
;
1153 spin_unlock_irqrestore(&gpio_lock
, flags
);
1156 gpiochip_unexport(chip
);
1160 EXPORT_SYMBOL_GPL(gpiochip_remove
);
1163 * gpiochip_find() - iterator for locating a specific gpio_chip
1164 * @data: data to pass to match function
1165 * @callback: Callback function to check gpio_chip
1167 * Similar to bus_find_device. It returns a reference to a gpio_chip as
1168 * determined by a user supplied @match callback. The callback should return
1169 * 0 if the device doesn't match and non-zero if it does. If the callback is
1170 * non-zero, this function will return to the caller and not iterate over any
1173 struct gpio_chip
*gpiochip_find(void *data
,
1174 int (*match
)(struct gpio_chip
*chip
, void *data
))
1176 struct gpio_chip
*chip
= NULL
;
1177 unsigned long flags
;
1180 spin_lock_irqsave(&gpio_lock
, flags
);
1181 for (i
= 0; i
< ARCH_NR_GPIOS
; i
++) {
1182 if (!gpio_desc
[i
].chip
)
1185 if (match(gpio_desc
[i
].chip
, data
)) {
1186 chip
= gpio_desc
[i
].chip
;
1190 spin_unlock_irqrestore(&gpio_lock
, flags
);
1195 /* These "optional" allocation calls help prevent drivers from stomping
1196 * on each other, and help provide better diagnostics in debugfs.
1197 * They're called even less than the "set direction" calls.
1199 int gpio_request(unsigned gpio
, const char *label
)
1201 struct gpio_desc
*desc
;
1202 struct gpio_chip
*chip
;
1203 int status
= -EINVAL
;
1204 unsigned long flags
;
1206 spin_lock_irqsave(&gpio_lock
, flags
);
1208 if (!gpio_is_valid(gpio
))
1210 desc
= &gpio_desc
[gpio
];
1215 if (!try_module_get(chip
->owner
))
1218 /* NOTE: gpio_request() can be called in early boot,
1219 * before IRQs are enabled, for non-sleeping (SOC) GPIOs.
1222 if (test_and_set_bit(FLAG_REQUESTED
, &desc
->flags
) == 0) {
1223 desc_set_label(desc
, label
? : "?");
1227 module_put(chip
->owner
);
1231 if (chip
->request
) {
1232 /* chip->request may sleep */
1233 spin_unlock_irqrestore(&gpio_lock
, flags
);
1234 status
= chip
->request(chip
, gpio
- chip
->base
);
1235 spin_lock_irqsave(&gpio_lock
, flags
);
1238 desc_set_label(desc
, NULL
);
1239 module_put(chip
->owner
);
1240 clear_bit(FLAG_REQUESTED
, &desc
->flags
);
1246 pr_debug("gpio_request: gpio-%d (%s) status %d\n",
1247 gpio
, label
? : "?", status
);
1248 spin_unlock_irqrestore(&gpio_lock
, flags
);
1251 EXPORT_SYMBOL_GPL(gpio_request
);
1253 void gpio_free(unsigned gpio
)
1255 unsigned long flags
;
1256 struct gpio_desc
*desc
;
1257 struct gpio_chip
*chip
;
1261 if (!gpio_is_valid(gpio
)) {
1262 WARN_ON(extra_checks
);
1266 gpio_unexport(gpio
);
1268 spin_lock_irqsave(&gpio_lock
, flags
);
1270 desc
= &gpio_desc
[gpio
];
1272 if (chip
&& test_bit(FLAG_REQUESTED
, &desc
->flags
)) {
1274 spin_unlock_irqrestore(&gpio_lock
, flags
);
1275 might_sleep_if(extra_checks
&& chip
->can_sleep
);
1276 chip
->free(chip
, gpio
- chip
->base
);
1277 spin_lock_irqsave(&gpio_lock
, flags
);
1279 desc_set_label(desc
, NULL
);
1280 module_put(desc
->chip
->owner
);
1281 clear_bit(FLAG_ACTIVE_LOW
, &desc
->flags
);
1282 clear_bit(FLAG_REQUESTED
, &desc
->flags
);
1284 WARN_ON(extra_checks
);
1286 spin_unlock_irqrestore(&gpio_lock
, flags
);
1288 EXPORT_SYMBOL_GPL(gpio_free
);
1291 * gpio_request_one - request a single GPIO with initial configuration
1292 * @gpio: the GPIO number
1293 * @flags: GPIO configuration as specified by GPIOF_*
1294 * @label: a literal description string of this GPIO
1296 int gpio_request_one(unsigned gpio
, unsigned long flags
, const char *label
)
1300 err
= gpio_request(gpio
, label
);
1304 if (flags
& GPIOF_DIR_IN
)
1305 err
= gpio_direction_input(gpio
);
1307 err
= gpio_direction_output(gpio
,
1308 (flags
& GPIOF_INIT_HIGH
) ? 1 : 0);
1312 EXPORT_SYMBOL_GPL(gpio_request_one
);
1315 * gpio_request_array - request multiple GPIOs in a single call
1316 * @array: array of the 'struct gpio'
1317 * @num: how many GPIOs in the array
1319 int gpio_request_array(struct gpio
*array
, size_t num
)
1323 for (i
= 0; i
< num
; i
++, array
++) {
1324 err
= gpio_request_one(array
->gpio
, array
->flags
, array
->label
);
1332 gpio_free((--array
)->gpio
);
1335 EXPORT_SYMBOL_GPL(gpio_request_array
);
1338 * gpio_free_array - release multiple GPIOs in a single call
1339 * @array: array of the 'struct gpio'
1340 * @num: how many GPIOs in the array
1342 void gpio_free_array(struct gpio
*array
, size_t num
)
1345 gpio_free((array
++)->gpio
);
1347 EXPORT_SYMBOL_GPL(gpio_free_array
);
1350 * gpiochip_is_requested - return string iff signal was requested
1351 * @chip: controller managing the signal
1352 * @offset: of signal within controller's 0..(ngpio - 1) range
1354 * Returns NULL if the GPIO is not currently requested, else a string.
1355 * If debugfs support is enabled, the string returned is the label passed
1356 * to gpio_request(); otherwise it is a meaningless constant.
1358 * This function is for use by GPIO controller drivers. The label can
1359 * help with diagnostics, and knowing that the signal is used as a GPIO
1360 * can help avoid accidentally multiplexing it to another controller.
1362 const char *gpiochip_is_requested(struct gpio_chip
*chip
, unsigned offset
)
1364 unsigned gpio
= chip
->base
+ offset
;
1366 if (!gpio_is_valid(gpio
) || gpio_desc
[gpio
].chip
!= chip
)
1368 if (test_bit(FLAG_REQUESTED
, &gpio_desc
[gpio
].flags
) == 0)
1370 #ifdef CONFIG_DEBUG_FS
1371 return gpio_desc
[gpio
].label
;
1376 EXPORT_SYMBOL_GPL(gpiochip_is_requested
);
1379 /* Drivers MUST set GPIO direction before making get/set calls. In
1380 * some cases this is done in early boot, before IRQs are enabled.
1382 * As a rule these aren't called more than once (except for drivers
1383 * using the open-drain emulation idiom) so these are natural places
1384 * to accumulate extra debugging checks. Note that we can't (yet)
1385 * rely on gpio_request() having been called beforehand.
1388 int gpio_direction_input(unsigned gpio
)
1390 unsigned long flags
;
1391 struct gpio_chip
*chip
;
1392 struct gpio_desc
*desc
= &gpio_desc
[gpio
];
1393 int status
= -EINVAL
;
1395 spin_lock_irqsave(&gpio_lock
, flags
);
1397 if (!gpio_is_valid(gpio
))
1400 if (!chip
|| !chip
->get
|| !chip
->direction_input
)
1403 if (gpio
>= chip
->ngpio
)
1405 status
= gpio_ensure_requested(desc
, gpio
);
1409 /* now we know the gpio is valid and chip won't vanish */
1411 spin_unlock_irqrestore(&gpio_lock
, flags
);
1413 might_sleep_if(extra_checks
&& chip
->can_sleep
);
1416 status
= chip
->request(chip
, gpio
);
1418 pr_debug("GPIO-%d: chip request fail, %d\n",
1419 chip
->base
+ gpio
, status
);
1420 /* and it's not available to anyone else ...
1421 * gpio_request() is the fully clean solution.
1427 status
= chip
->direction_input(chip
, gpio
);
1429 clear_bit(FLAG_IS_OUT
, &desc
->flags
);
1433 spin_unlock_irqrestore(&gpio_lock
, flags
);
1435 pr_debug("%s: gpio-%d status %d\n",
1436 __func__
, gpio
, status
);
1439 EXPORT_SYMBOL_GPL(gpio_direction_input
);
1441 int gpio_direction_output(unsigned gpio
, int value
)
1443 unsigned long flags
;
1444 struct gpio_chip
*chip
;
1445 struct gpio_desc
*desc
= &gpio_desc
[gpio
];
1446 int status
= -EINVAL
;
1448 spin_lock_irqsave(&gpio_lock
, flags
);
1450 if (!gpio_is_valid(gpio
))
1453 if (!chip
|| !chip
->set
|| !chip
->direction_output
)
1456 if (gpio
>= chip
->ngpio
)
1458 status
= gpio_ensure_requested(desc
, gpio
);
1462 /* now we know the gpio is valid and chip won't vanish */
1464 spin_unlock_irqrestore(&gpio_lock
, flags
);
1466 might_sleep_if(extra_checks
&& chip
->can_sleep
);
1469 status
= chip
->request(chip
, gpio
);
1471 pr_debug("GPIO-%d: chip request fail, %d\n",
1472 chip
->base
+ gpio
, status
);
1473 /* and it's not available to anyone else ...
1474 * gpio_request() is the fully clean solution.
1480 status
= chip
->direction_output(chip
, gpio
, value
);
1482 set_bit(FLAG_IS_OUT
, &desc
->flags
);
1486 spin_unlock_irqrestore(&gpio_lock
, flags
);
1488 pr_debug("%s: gpio-%d status %d\n",
1489 __func__
, gpio
, status
);
1492 EXPORT_SYMBOL_GPL(gpio_direction_output
);
1495 * gpio_set_debounce - sets @debounce time for a @gpio
1496 * @gpio: the gpio to set debounce time
1497 * @debounce: debounce time is microseconds
1499 int gpio_set_debounce(unsigned gpio
, unsigned debounce
)
1501 unsigned long flags
;
1502 struct gpio_chip
*chip
;
1503 struct gpio_desc
*desc
= &gpio_desc
[gpio
];
1504 int status
= -EINVAL
;
1506 spin_lock_irqsave(&gpio_lock
, flags
);
1508 if (!gpio_is_valid(gpio
))
1511 if (!chip
|| !chip
->set
|| !chip
->set_debounce
)
1514 if (gpio
>= chip
->ngpio
)
1516 status
= gpio_ensure_requested(desc
, gpio
);
1520 /* now we know the gpio is valid and chip won't vanish */
1522 spin_unlock_irqrestore(&gpio_lock
, flags
);
1524 might_sleep_if(extra_checks
&& chip
->can_sleep
);
1526 return chip
->set_debounce(chip
, gpio
, debounce
);
1529 spin_unlock_irqrestore(&gpio_lock
, flags
);
1531 pr_debug("%s: gpio-%d status %d\n",
1532 __func__
, gpio
, status
);
1536 EXPORT_SYMBOL_GPL(gpio_set_debounce
);
1538 /* I/O calls are only valid after configuration completed; the relevant
1539 * "is this a valid GPIO" error checks should already have been done.
1541 * "Get" operations are often inlinable as reading a pin value register,
1542 * and masking the relevant bit in that register.
1544 * When "set" operations are inlinable, they involve writing that mask to
1545 * one register to set a low value, or a different register to set it high.
1546 * Otherwise locking is needed, so there may be little value to inlining.
1548 *------------------------------------------------------------------------
1550 * IMPORTANT!!! The hot paths -- get/set value -- assume that callers
1551 * have requested the GPIO. That can include implicit requesting by
1552 * a direction setting call. Marking a gpio as requested locks its chip
1553 * in memory, guaranteeing that these table lookups need no more locking
1554 * and that gpiochip_remove() will fail.
1556 * REVISIT when debugging, consider adding some instrumentation to ensure
1557 * that the GPIO was actually requested.
1561 * __gpio_get_value() - return a gpio's value
1562 * @gpio: gpio whose value will be returned
1565 * This is used directly or indirectly to implement gpio_get_value().
1566 * It returns the zero or nonzero value provided by the associated
1567 * gpio_chip.get() method; or zero if no such method is provided.
1569 int __gpio_get_value(unsigned gpio
)
1571 struct gpio_chip
*chip
;
1573 chip
= gpio_to_chip(gpio
);
1574 WARN_ON(extra_checks
&& chip
->can_sleep
);
1575 return chip
->get
? chip
->get(chip
, gpio
- chip
->base
) : 0;
1577 EXPORT_SYMBOL_GPL(__gpio_get_value
);
1580 * __gpio_set_value() - assign a gpio's value
1581 * @gpio: gpio whose value will be assigned
1582 * @value: value to assign
1585 * This is used directly or indirectly to implement gpio_set_value().
1586 * It invokes the associated gpio_chip.set() method.
1588 void __gpio_set_value(unsigned gpio
, int value
)
1590 struct gpio_chip
*chip
;
1592 chip
= gpio_to_chip(gpio
);
1593 WARN_ON(extra_checks
&& chip
->can_sleep
);
1594 chip
->set(chip
, gpio
- chip
->base
, value
);
1596 EXPORT_SYMBOL_GPL(__gpio_set_value
);
1599 * __gpio_cansleep() - report whether gpio value access will sleep
1600 * @gpio: gpio in question
1603 * This is used directly or indirectly to implement gpio_cansleep(). It
1604 * returns nonzero if access reading or writing the GPIO value can sleep.
1606 int __gpio_cansleep(unsigned gpio
)
1608 struct gpio_chip
*chip
;
1610 /* only call this on GPIOs that are valid! */
1611 chip
= gpio_to_chip(gpio
);
1613 return chip
->can_sleep
;
1615 EXPORT_SYMBOL_GPL(__gpio_cansleep
);
1618 * __gpio_to_irq() - return the IRQ corresponding to a GPIO
1619 * @gpio: gpio whose IRQ will be returned (already requested)
1622 * This is used directly or indirectly to implement gpio_to_irq().
1623 * It returns the number of the IRQ signaled by this (input) GPIO,
1624 * or a negative errno.
1626 int __gpio_to_irq(unsigned gpio
)
1628 struct gpio_chip
*chip
;
1630 chip
= gpio_to_chip(gpio
);
1631 return chip
->to_irq
? chip
->to_irq(chip
, gpio
- chip
->base
) : -ENXIO
;
1633 EXPORT_SYMBOL_GPL(__gpio_to_irq
);
1637 /* There's no value in making it easy to inline GPIO calls that may sleep.
1638 * Common examples include ones connected to I2C or SPI chips.
1641 int gpio_get_value_cansleep(unsigned gpio
)
1643 struct gpio_chip
*chip
;
1645 might_sleep_if(extra_checks
);
1646 chip
= gpio_to_chip(gpio
);
1647 return chip
->get
? chip
->get(chip
, gpio
- chip
->base
) : 0;
1649 EXPORT_SYMBOL_GPL(gpio_get_value_cansleep
);
1651 void gpio_set_value_cansleep(unsigned gpio
, int value
)
1653 struct gpio_chip
*chip
;
1655 might_sleep_if(extra_checks
);
1656 chip
= gpio_to_chip(gpio
);
1657 chip
->set(chip
, gpio
- chip
->base
, value
);
1659 EXPORT_SYMBOL_GPL(gpio_set_value_cansleep
);
1662 #ifdef CONFIG_DEBUG_FS
1664 static void gpiolib_dbg_show(struct seq_file
*s
, struct gpio_chip
*chip
)
1667 unsigned gpio
= chip
->base
;
1668 struct gpio_desc
*gdesc
= &gpio_desc
[gpio
];
1671 for (i
= 0; i
< chip
->ngpio
; i
++, gpio
++, gdesc
++) {
1672 if (!test_bit(FLAG_REQUESTED
, &gdesc
->flags
))
1675 is_out
= test_bit(FLAG_IS_OUT
, &gdesc
->flags
);
1676 seq_printf(s
, " gpio-%-3d (%-20.20s) %s %s",
1678 is_out
? "out" : "in ",
1680 ? (chip
->get(chip
, i
) ? "hi" : "lo")
1684 int irq
= gpio_to_irq(gpio
);
1685 struct irq_desc
*desc
= irq_to_desc(irq
);
1687 /* This races with request_irq(), set_irq_type(),
1688 * and set_irq_wake() ... but those are "rare".
1690 * More significantly, trigger type flags aren't
1691 * currently maintained by genirq.
1693 if (irq
>= 0 && desc
->action
) {
1696 switch (desc
->status
& IRQ_TYPE_SENSE_MASK
) {
1698 trigger
= "(default)";
1700 case IRQ_TYPE_EDGE_FALLING
:
1701 trigger
= "edge-falling";
1703 case IRQ_TYPE_EDGE_RISING
:
1704 trigger
= "edge-rising";
1706 case IRQ_TYPE_EDGE_BOTH
:
1707 trigger
= "edge-both";
1709 case IRQ_TYPE_LEVEL_HIGH
:
1710 trigger
= "level-high";
1712 case IRQ_TYPE_LEVEL_LOW
:
1713 trigger
= "level-low";
1716 trigger
= "?trigger?";
1720 seq_printf(s
, " irq-%d %s%s",
1722 (desc
->status
& IRQ_WAKEUP
)
1727 seq_printf(s
, "\n");
1731 static int gpiolib_show(struct seq_file
*s
, void *unused
)
1733 struct gpio_chip
*chip
= NULL
;
1737 /* REVISIT this isn't locked against gpio_chip removal ... */
1739 for (gpio
= 0; gpio_is_valid(gpio
); gpio
++) {
1742 if (chip
== gpio_desc
[gpio
].chip
)
1744 chip
= gpio_desc
[gpio
].chip
;
1748 seq_printf(s
, "%sGPIOs %d-%d",
1749 started
? "\n" : "",
1750 chip
->base
, chip
->base
+ chip
->ngpio
- 1);
1753 seq_printf(s
, ", %s/%s",
1754 dev
->bus
? dev
->bus
->name
: "no-bus",
1757 seq_printf(s
, ", %s", chip
->label
);
1758 if (chip
->can_sleep
)
1759 seq_printf(s
, ", can sleep");
1760 seq_printf(s
, ":\n");
1764 chip
->dbg_show(s
, chip
);
1766 gpiolib_dbg_show(s
, chip
);
1771 static int gpiolib_open(struct inode
*inode
, struct file
*file
)
1773 return single_open(file
, gpiolib_show
, NULL
);
1776 static const struct file_operations gpiolib_operations
= {
1777 .open
= gpiolib_open
,
1779 .llseek
= seq_lseek
,
1780 .release
= single_release
,
1783 static int __init
gpiolib_debugfs_init(void)
1785 /* /sys/kernel/debug/gpio */
1786 (void) debugfs_create_file("gpio", S_IFREG
| S_IRUGO
,
1787 NULL
, NULL
, &gpiolib_operations
);
1790 subsys_initcall(gpiolib_debugfs_init
);
1792 #endif /* DEBUG_FS */