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_set_debounce(struct gpio_desc
*desc
, unsigned debounce
);
92 static int gpiod_get_value_cansleep(struct gpio_desc
*desc
);
93 static void gpiod_set_value_cansleep(struct gpio_desc
*desc
, int value
);
94 static int gpiod_get_value(struct gpio_desc
*desc
);
95 static void gpiod_set_value(struct gpio_desc
*desc
, int value
);
96 static int gpiod_cansleep(struct gpio_desc
*desc
);
97 static int gpiod_to_irq(struct gpio_desc
*desc
);
98 static int gpiod_export(struct gpio_desc
*desc
, bool direction_may_change
);
99 static int gpiod_export_link(struct device
*dev
, const char *name
,
100 struct gpio_desc
*desc
);
101 static int gpiod_sysfs_set_active_low(struct gpio_desc
*desc
, int value
);
102 static void gpiod_unexport(struct gpio_desc
*desc
);
105 static inline void desc_set_label(struct gpio_desc
*d
, const char *label
)
107 #ifdef CONFIG_DEBUG_FS
113 * Return the GPIO number of the passed descriptor relative to its chip
115 static int gpio_chip_hwgpio(const struct gpio_desc
*desc
)
117 return desc
- &desc
->chip
->desc
[0];
121 * Convert a GPIO number to its descriptor
123 static struct gpio_desc
*gpio_to_desc(unsigned gpio
)
125 if (WARN(!gpio_is_valid(gpio
), "invalid GPIO %d\n", gpio
))
128 return &gpio_desc
[gpio
];
132 * Convert a GPIO descriptor to the integer namespace.
133 * This should disappear in the future but is needed since we still
134 * use GPIO numbers for error messages and sysfs nodes
136 static int desc_to_gpio(const struct gpio_desc
*desc
)
138 return desc
->chip
->base
+ gpio_chip_hwgpio(desc
);
142 /* Warn when drivers omit gpio_request() calls -- legal but ill-advised
143 * when setting direction, and otherwise illegal. Until board setup code
144 * and drivers use explicit requests everywhere (which won't happen when
145 * those calls have no teeth) we can't avoid autorequesting. This nag
146 * message should motivate switching to explicit requests... so should
147 * the weaker cleanup after faults, compared to gpio_request().
149 * NOTE: the autorequest mechanism is going away; at this point it's
150 * only "legal" in the sense that (old) code using it won't break yet,
151 * but instead only triggers a WARN() stack dump.
153 static int gpio_ensure_requested(struct gpio_desc
*desc
)
155 const struct gpio_chip
*chip
= desc
->chip
;
156 const int gpio
= desc_to_gpio(desc
);
158 if (WARN(test_and_set_bit(FLAG_REQUESTED
, &desc
->flags
) == 0,
159 "autorequest GPIO-%d\n", gpio
)) {
160 if (!try_module_get(chip
->owner
)) {
161 pr_err("GPIO-%d: module can't be gotten \n", gpio
);
162 clear_bit(FLAG_REQUESTED
, &desc
->flags
);
166 desc_set_label(desc
, "[auto]");
167 /* caller must chip->request() w/o spinlock */
174 /* caller holds gpio_lock *OR* gpio is marked as requested */
175 static struct gpio_chip
*gpiod_to_chip(struct gpio_desc
*desc
)
180 struct gpio_chip
*gpio_to_chip(unsigned gpio
)
182 return gpiod_to_chip(gpio_to_desc(gpio
));
185 /* dynamic allocation of GPIOs, e.g. on a hotplugged device */
186 static int gpiochip_find_base(int ngpio
)
188 struct gpio_chip
*chip
;
189 int base
= ARCH_NR_GPIOS
- ngpio
;
191 list_for_each_entry_reverse(chip
, &gpio_chips
, list
) {
192 /* found a free space? */
193 if (chip
->base
+ chip
->ngpio
<= base
)
196 /* nope, check the space right before the chip */
197 base
= chip
->base
- ngpio
;
200 if (gpio_is_valid(base
)) {
201 pr_debug("%s: found new base at %d\n", __func__
, base
);
204 pr_err("%s: cannot find free range\n", __func__
);
209 /* caller ensures gpio is valid and requested, chip->get_direction may sleep */
210 static int gpiod_get_direction(struct gpio_desc
*desc
)
212 struct gpio_chip
*chip
;
214 int status
= -EINVAL
;
216 chip
= gpiod_to_chip(desc
);
217 offset
= gpio_chip_hwgpio(desc
);
219 if (!chip
->get_direction
)
222 status
= chip
->get_direction(chip
, offset
);
224 /* GPIOF_DIR_IN, or other positive */
226 clear_bit(FLAG_IS_OUT
, &desc
->flags
);
230 set_bit(FLAG_IS_OUT
, &desc
->flags
);
235 #ifdef CONFIG_GPIO_SYSFS
237 /* lock protects against unexport_gpio() being called while
238 * sysfs files are active.
240 static DEFINE_MUTEX(sysfs_lock
);
243 * /sys/class/gpio/gpioN... only for GPIOs that are exported
245 * * MAY BE OMITTED if kernel won't allow direction changes
246 * * is read/write as "in" or "out"
247 * * may also be written as "high" or "low", initializing
248 * output value as specified ("out" implies "low")
250 * * always readable, subject to hardware behavior
251 * * may be writable, as zero/nonzero
253 * * configures behavior of poll(2) on /value
254 * * available only if pin can generate IRQs on input
255 * * is read/write as "none", "falling", "rising", or "both"
257 * * configures polarity of /value
258 * * is read/write as zero/nonzero
259 * * also affects existing and subsequent "falling" and "rising"
260 * /edge configuration
263 static ssize_t
gpio_direction_show(struct device
*dev
,
264 struct device_attribute
*attr
, char *buf
)
266 struct gpio_desc
*desc
= dev_get_drvdata(dev
);
269 mutex_lock(&sysfs_lock
);
271 if (!test_bit(FLAG_EXPORT
, &desc
->flags
)) {
274 gpiod_get_direction(desc
);
275 status
= sprintf(buf
, "%s\n",
276 test_bit(FLAG_IS_OUT
, &desc
->flags
)
280 mutex_unlock(&sysfs_lock
);
284 static ssize_t
gpio_direction_store(struct device
*dev
,
285 struct device_attribute
*attr
, const char *buf
, size_t size
)
287 struct gpio_desc
*desc
= dev_get_drvdata(dev
);
290 mutex_lock(&sysfs_lock
);
292 if (!test_bit(FLAG_EXPORT
, &desc
->flags
))
294 else if (sysfs_streq(buf
, "high"))
295 status
= gpiod_direction_output(desc
, 1);
296 else if (sysfs_streq(buf
, "out") || sysfs_streq(buf
, "low"))
297 status
= gpiod_direction_output(desc
, 0);
298 else if (sysfs_streq(buf
, "in"))
299 status
= gpiod_direction_input(desc
);
303 mutex_unlock(&sysfs_lock
);
304 return status
? : size
;
307 static /* const */ DEVICE_ATTR(direction
, 0644,
308 gpio_direction_show
, gpio_direction_store
);
310 static ssize_t
gpio_value_show(struct device
*dev
,
311 struct device_attribute
*attr
, char *buf
)
313 struct gpio_desc
*desc
= dev_get_drvdata(dev
);
316 mutex_lock(&sysfs_lock
);
318 if (!test_bit(FLAG_EXPORT
, &desc
->flags
)) {
323 value
= !!gpiod_get_value_cansleep(desc
);
324 if (test_bit(FLAG_ACTIVE_LOW
, &desc
->flags
))
327 status
= sprintf(buf
, "%d\n", value
);
330 mutex_unlock(&sysfs_lock
);
334 static ssize_t
gpio_value_store(struct device
*dev
,
335 struct device_attribute
*attr
, const char *buf
, size_t size
)
337 struct gpio_desc
*desc
= dev_get_drvdata(dev
);
340 mutex_lock(&sysfs_lock
);
342 if (!test_bit(FLAG_EXPORT
, &desc
->flags
))
344 else if (!test_bit(FLAG_IS_OUT
, &desc
->flags
))
349 status
= strict_strtol(buf
, 0, &value
);
351 if (test_bit(FLAG_ACTIVE_LOW
, &desc
->flags
))
353 gpiod_set_value_cansleep(desc
, value
!= 0);
358 mutex_unlock(&sysfs_lock
);
362 static const DEVICE_ATTR(value
, 0644,
363 gpio_value_show
, gpio_value_store
);
365 static irqreturn_t
gpio_sysfs_irq(int irq
, void *priv
)
367 struct sysfs_dirent
*value_sd
= priv
;
369 sysfs_notify_dirent(value_sd
);
373 static int gpio_setup_irq(struct gpio_desc
*desc
, struct device
*dev
,
374 unsigned long gpio_flags
)
376 struct sysfs_dirent
*value_sd
;
377 unsigned long irq_flags
;
380 if ((desc
->flags
& GPIO_TRIGGER_MASK
) == gpio_flags
)
383 irq
= gpiod_to_irq(desc
);
387 id
= desc
->flags
>> ID_SHIFT
;
388 value_sd
= idr_find(&dirent_idr
, id
);
390 free_irq(irq
, value_sd
);
392 desc
->flags
&= ~GPIO_TRIGGER_MASK
;
399 irq_flags
= IRQF_SHARED
;
400 if (test_bit(FLAG_TRIG_FALL
, &gpio_flags
))
401 irq_flags
|= test_bit(FLAG_ACTIVE_LOW
, &desc
->flags
) ?
402 IRQF_TRIGGER_RISING
: IRQF_TRIGGER_FALLING
;
403 if (test_bit(FLAG_TRIG_RISE
, &gpio_flags
))
404 irq_flags
|= test_bit(FLAG_ACTIVE_LOW
, &desc
->flags
) ?
405 IRQF_TRIGGER_FALLING
: IRQF_TRIGGER_RISING
;
408 value_sd
= sysfs_get_dirent(dev
->kobj
.sd
, NULL
, "value");
416 if (idr_pre_get(&dirent_idr
, GFP_KERNEL
))
417 ret
= idr_get_new_above(&dirent_idr
, value_sd
,
419 } while (ret
== -EAGAIN
);
424 desc
->flags
&= GPIO_FLAGS_MASK
;
425 desc
->flags
|= (unsigned long)id
<< ID_SHIFT
;
427 if (desc
->flags
>> ID_SHIFT
!= id
) {
433 ret
= request_any_context_irq(irq
, gpio_sysfs_irq
, irq_flags
,
434 "gpiolib", value_sd
);
438 desc
->flags
|= gpio_flags
;
442 idr_remove(&dirent_idr
, id
);
443 desc
->flags
&= GPIO_FLAGS_MASK
;
451 static const struct {
454 } trigger_types
[] = {
456 { "falling", BIT(FLAG_TRIG_FALL
) },
457 { "rising", BIT(FLAG_TRIG_RISE
) },
458 { "both", BIT(FLAG_TRIG_FALL
) | BIT(FLAG_TRIG_RISE
) },
461 static ssize_t
gpio_edge_show(struct device
*dev
,
462 struct device_attribute
*attr
, char *buf
)
464 const struct gpio_desc
*desc
= dev_get_drvdata(dev
);
467 mutex_lock(&sysfs_lock
);
469 if (!test_bit(FLAG_EXPORT
, &desc
->flags
))
475 for (i
= 0; i
< ARRAY_SIZE(trigger_types
); i
++)
476 if ((desc
->flags
& GPIO_TRIGGER_MASK
)
477 == trigger_types
[i
].flags
) {
478 status
= sprintf(buf
, "%s\n",
479 trigger_types
[i
].name
);
484 mutex_unlock(&sysfs_lock
);
488 static ssize_t
gpio_edge_store(struct device
*dev
,
489 struct device_attribute
*attr
, const char *buf
, size_t size
)
491 struct gpio_desc
*desc
= dev_get_drvdata(dev
);
495 for (i
= 0; i
< ARRAY_SIZE(trigger_types
); i
++)
496 if (sysfs_streq(trigger_types
[i
].name
, buf
))
501 mutex_lock(&sysfs_lock
);
503 if (!test_bit(FLAG_EXPORT
, &desc
->flags
))
506 status
= gpio_setup_irq(desc
, dev
, trigger_types
[i
].flags
);
511 mutex_unlock(&sysfs_lock
);
516 static DEVICE_ATTR(edge
, 0644, gpio_edge_show
, gpio_edge_store
);
518 static int sysfs_set_active_low(struct gpio_desc
*desc
, struct device
*dev
,
523 if (!!test_bit(FLAG_ACTIVE_LOW
, &desc
->flags
) == !!value
)
527 set_bit(FLAG_ACTIVE_LOW
, &desc
->flags
);
529 clear_bit(FLAG_ACTIVE_LOW
, &desc
->flags
);
531 /* reconfigure poll(2) support if enabled on one edge only */
532 if (dev
!= NULL
&& (!!test_bit(FLAG_TRIG_RISE
, &desc
->flags
) ^
533 !!test_bit(FLAG_TRIG_FALL
, &desc
->flags
))) {
534 unsigned long trigger_flags
= desc
->flags
& GPIO_TRIGGER_MASK
;
536 gpio_setup_irq(desc
, dev
, 0);
537 status
= gpio_setup_irq(desc
, dev
, trigger_flags
);
543 static ssize_t
gpio_active_low_show(struct device
*dev
,
544 struct device_attribute
*attr
, char *buf
)
546 const struct gpio_desc
*desc
= dev_get_drvdata(dev
);
549 mutex_lock(&sysfs_lock
);
551 if (!test_bit(FLAG_EXPORT
, &desc
->flags
))
554 status
= sprintf(buf
, "%d\n",
555 !!test_bit(FLAG_ACTIVE_LOW
, &desc
->flags
));
557 mutex_unlock(&sysfs_lock
);
562 static ssize_t
gpio_active_low_store(struct device
*dev
,
563 struct device_attribute
*attr
, const char *buf
, size_t size
)
565 struct gpio_desc
*desc
= dev_get_drvdata(dev
);
568 mutex_lock(&sysfs_lock
);
570 if (!test_bit(FLAG_EXPORT
, &desc
->flags
)) {
575 status
= strict_strtol(buf
, 0, &value
);
577 status
= sysfs_set_active_low(desc
, dev
, value
!= 0);
580 mutex_unlock(&sysfs_lock
);
582 return status
? : size
;
585 static const DEVICE_ATTR(active_low
, 0644,
586 gpio_active_low_show
, gpio_active_low_store
);
588 static const struct attribute
*gpio_attrs
[] = {
589 &dev_attr_value
.attr
,
590 &dev_attr_active_low
.attr
,
594 static const struct attribute_group gpio_attr_group
= {
595 .attrs
= (struct attribute
**) gpio_attrs
,
599 * /sys/class/gpio/gpiochipN/
600 * /base ... matching gpio_chip.base (N)
601 * /label ... matching gpio_chip.label
602 * /ngpio ... matching gpio_chip.ngpio
605 static ssize_t
chip_base_show(struct device
*dev
,
606 struct device_attribute
*attr
, char *buf
)
608 const struct gpio_chip
*chip
= dev_get_drvdata(dev
);
610 return sprintf(buf
, "%d\n", chip
->base
);
612 static DEVICE_ATTR(base
, 0444, chip_base_show
, NULL
);
614 static ssize_t
chip_label_show(struct device
*dev
,
615 struct device_attribute
*attr
, char *buf
)
617 const struct gpio_chip
*chip
= dev_get_drvdata(dev
);
619 return sprintf(buf
, "%s\n", chip
->label
? : "");
621 static DEVICE_ATTR(label
, 0444, chip_label_show
, NULL
);
623 static ssize_t
chip_ngpio_show(struct device
*dev
,
624 struct device_attribute
*attr
, char *buf
)
626 const struct gpio_chip
*chip
= dev_get_drvdata(dev
);
628 return sprintf(buf
, "%u\n", chip
->ngpio
);
630 static DEVICE_ATTR(ngpio
, 0444, chip_ngpio_show
, NULL
);
632 static const struct attribute
*gpiochip_attrs
[] = {
634 &dev_attr_label
.attr
,
635 &dev_attr_ngpio
.attr
,
639 static const struct attribute_group gpiochip_attr_group
= {
640 .attrs
= (struct attribute
**) gpiochip_attrs
,
644 * /sys/class/gpio/export ... write-only
645 * integer N ... number of GPIO to export (full access)
646 * /sys/class/gpio/unexport ... write-only
647 * integer N ... number of GPIO to unexport
649 static ssize_t
export_store(struct class *class,
650 struct class_attribute
*attr
,
651 const char *buf
, size_t len
)
654 struct gpio_desc
*desc
;
657 status
= strict_strtol(buf
, 0, &gpio
);
661 desc
= gpio_to_desc(gpio
);
663 /* No extra locking here; FLAG_SYSFS just signifies that the
664 * request and export were done by on behalf of userspace, so
665 * they may be undone on its behalf too.
668 status
= gpiod_request(desc
, "sysfs");
670 if (status
== -EPROBE_DEFER
)
674 status
= gpiod_export(desc
, true);
678 set_bit(FLAG_SYSFS
, &desc
->flags
);
682 pr_debug("%s: status %d\n", __func__
, status
);
683 return status
? : len
;
686 static ssize_t
unexport_store(struct class *class,
687 struct class_attribute
*attr
,
688 const char *buf
, size_t len
)
691 struct gpio_desc
*desc
;
694 status
= strict_strtol(buf
, 0, &gpio
);
700 desc
= gpio_to_desc(gpio
);
701 /* reject bogus commands (gpio_unexport ignores them) */
705 /* No extra locking here; FLAG_SYSFS just signifies that the
706 * request and export were done by on behalf of userspace, so
707 * they may be undone on its behalf too.
709 if (test_and_clear_bit(FLAG_SYSFS
, &desc
->flags
)) {
715 pr_debug("%s: status %d\n", __func__
, status
);
716 return status
? : len
;
719 static struct class_attribute gpio_class_attrs
[] = {
720 __ATTR(export
, 0200, NULL
, export_store
),
721 __ATTR(unexport
, 0200, NULL
, unexport_store
),
725 static struct class gpio_class
= {
727 .owner
= THIS_MODULE
,
729 .class_attrs
= gpio_class_attrs
,
734 * gpio_export - export a GPIO through sysfs
735 * @gpio: gpio to make available, already requested
736 * @direction_may_change: true if userspace may change gpio direction
737 * Context: arch_initcall or later
739 * When drivers want to make a GPIO accessible to userspace after they
740 * have requested it -- perhaps while debugging, or as part of their
741 * public interface -- they may use this routine. If the GPIO can
742 * change direction (some can't) and the caller allows it, userspace
743 * will see "direction" sysfs attribute which may be used to change
744 * the gpio's direction. A "value" attribute will always be provided.
746 * Returns zero on success, else an error.
748 static int gpiod_export(struct gpio_desc
*desc
, bool direction_may_change
)
752 const char *ioname
= NULL
;
756 /* can't export until sysfs is available ... */
758 pr_debug("%s: called too early!\n", __func__
);
763 pr_debug("%s: invalid gpio descriptor\n", __func__
);
767 mutex_lock(&sysfs_lock
);
769 spin_lock_irqsave(&gpio_lock
, flags
);
770 if (!test_bit(FLAG_REQUESTED
, &desc
->flags
) ||
771 test_bit(FLAG_EXPORT
, &desc
->flags
)) {
772 spin_unlock_irqrestore(&gpio_lock
, flags
);
773 pr_debug("%s: gpio %d unavailable (requested=%d, exported=%d)\n",
774 __func__
, desc_to_gpio(desc
),
775 test_bit(FLAG_REQUESTED
, &desc
->flags
),
776 test_bit(FLAG_EXPORT
, &desc
->flags
));
781 if (!desc
->chip
->direction_input
|| !desc
->chip
->direction_output
)
782 direction_may_change
= false;
783 spin_unlock_irqrestore(&gpio_lock
, flags
);
785 offset
= gpio_chip_hwgpio(desc
);
786 if (desc
->chip
->names
&& desc
->chip
->names
[offset
])
787 ioname
= desc
->chip
->names
[offset
];
789 dev
= device_create(&gpio_class
, desc
->chip
->dev
, MKDEV(0, 0),
790 desc
, ioname
? ioname
: "gpio%u",
793 status
= PTR_ERR(dev
);
797 status
= sysfs_create_group(&dev
->kobj
, &gpio_attr_group
);
799 goto fail_unregister_device
;
801 if (direction_may_change
) {
802 status
= device_create_file(dev
, &dev_attr_direction
);
804 goto fail_unregister_device
;
807 if (gpiod_to_irq(desc
) >= 0 && (direction_may_change
||
808 !test_bit(FLAG_IS_OUT
, &desc
->flags
))) {
809 status
= device_create_file(dev
, &dev_attr_edge
);
811 goto fail_unregister_device
;
814 set_bit(FLAG_EXPORT
, &desc
->flags
);
815 mutex_unlock(&sysfs_lock
);
818 fail_unregister_device
:
819 device_unregister(dev
);
821 mutex_unlock(&sysfs_lock
);
822 pr_debug("%s: gpio%d status %d\n", __func__
, desc_to_gpio(desc
),
827 int gpio_export(unsigned gpio
, bool direction_may_change
)
829 return gpiod_export(gpio_to_desc(gpio
), direction_may_change
);
831 EXPORT_SYMBOL_GPL(gpio_export
);
833 static int match_export(struct device
*dev
, const void *data
)
835 return dev_get_drvdata(dev
) == data
;
839 * gpio_export_link - create a sysfs link to an exported GPIO node
840 * @dev: device under which to create symlink
841 * @name: name of the symlink
842 * @gpio: gpio to create symlink to, already exported
844 * Set up a symlink from /sys/.../dev/name to /sys/class/gpio/gpioN
845 * node. Caller is responsible for unlinking.
847 * Returns zero on success, else an error.
849 static int gpiod_export_link(struct device
*dev
, const char *name
,
850 struct gpio_desc
*desc
)
852 int status
= -EINVAL
;
857 mutex_lock(&sysfs_lock
);
859 if (test_bit(FLAG_EXPORT
, &desc
->flags
)) {
862 tdev
= class_find_device(&gpio_class
, NULL
, desc
, match_export
);
864 status
= sysfs_create_link(&dev
->kobj
, &tdev
->kobj
,
871 mutex_unlock(&sysfs_lock
);
875 pr_debug("%s: gpio%d status %d\n", __func__
, desc_to_gpio(desc
),
881 int gpio_export_link(struct device
*dev
, const char *name
, unsigned gpio
)
883 return gpiod_export_link(dev
, name
, gpio_to_desc(gpio
));
885 EXPORT_SYMBOL_GPL(gpio_export_link
);
888 * gpio_sysfs_set_active_low - set the polarity of gpio sysfs value
889 * @gpio: gpio to change
890 * @value: non-zero to use active low, i.e. inverted values
892 * Set the polarity of /sys/class/gpio/gpioN/value sysfs attribute.
893 * The GPIO does not have to be exported yet. If poll(2) support has
894 * been enabled for either rising or falling edge, it will be
895 * reconfigured to follow the new polarity.
897 * Returns zero on success, else an error.
899 static int gpiod_sysfs_set_active_low(struct gpio_desc
*desc
, int value
)
901 struct device
*dev
= NULL
;
902 int status
= -EINVAL
;
907 mutex_lock(&sysfs_lock
);
909 if (test_bit(FLAG_EXPORT
, &desc
->flags
)) {
910 dev
= class_find_device(&gpio_class
, NULL
, desc
, match_export
);
917 status
= sysfs_set_active_low(desc
, dev
, value
);
920 mutex_unlock(&sysfs_lock
);
924 pr_debug("%s: gpio%d status %d\n", __func__
, desc_to_gpio(desc
),
930 int gpio_sysfs_set_active_low(unsigned gpio
, int value
)
932 return gpiod_sysfs_set_active_low(gpio_to_desc(gpio
), value
);
934 EXPORT_SYMBOL_GPL(gpio_sysfs_set_active_low
);
937 * gpio_unexport - reverse effect of gpio_export()
938 * @gpio: gpio to make unavailable
940 * This is implicit on gpio_free().
942 static void gpiod_unexport(struct gpio_desc
*desc
)
945 struct device
*dev
= NULL
;
952 mutex_lock(&sysfs_lock
);
954 if (test_bit(FLAG_EXPORT
, &desc
->flags
)) {
956 dev
= class_find_device(&gpio_class
, NULL
, desc
, match_export
);
958 gpio_setup_irq(desc
, dev
, 0);
959 clear_bit(FLAG_EXPORT
, &desc
->flags
);
964 mutex_unlock(&sysfs_lock
);
967 device_unregister(dev
);
972 pr_debug("%s: gpio%d status %d\n", __func__
, desc_to_gpio(desc
),
976 void gpio_unexport(unsigned gpio
)
978 gpiod_unexport(gpio_to_desc(gpio
));
980 EXPORT_SYMBOL_GPL(gpio_unexport
);
982 static int gpiochip_export(struct gpio_chip
*chip
)
987 /* Many systems register gpio chips for SOC support very early,
988 * before driver model support is available. In those cases we
989 * export this later, in gpiolib_sysfs_init() ... here we just
990 * verify that _some_ field of gpio_class got initialized.
995 /* use chip->base for the ID; it's already known to be unique */
996 mutex_lock(&sysfs_lock
);
997 dev
= device_create(&gpio_class
, chip
->dev
, MKDEV(0, 0), chip
,
998 "gpiochip%d", chip
->base
);
1000 status
= sysfs_create_group(&dev
->kobj
,
1001 &gpiochip_attr_group
);
1003 status
= PTR_ERR(dev
);
1004 chip
->exported
= (status
== 0);
1005 mutex_unlock(&sysfs_lock
);
1008 unsigned long flags
;
1011 spin_lock_irqsave(&gpio_lock
, flags
);
1013 while (gpio
< chip
->ngpio
)
1014 chip
->desc
[gpio
++].chip
= NULL
;
1015 spin_unlock_irqrestore(&gpio_lock
, flags
);
1017 pr_debug("%s: chip %s status %d\n", __func__
,
1018 chip
->label
, status
);
1024 static void gpiochip_unexport(struct gpio_chip
*chip
)
1029 mutex_lock(&sysfs_lock
);
1030 dev
= class_find_device(&gpio_class
, NULL
, chip
, match_export
);
1033 device_unregister(dev
);
1038 mutex_unlock(&sysfs_lock
);
1041 pr_debug("%s: chip %s status %d\n", __func__
,
1042 chip
->label
, status
);
1045 static int __init
gpiolib_sysfs_init(void)
1048 unsigned long flags
;
1049 struct gpio_chip
*chip
;
1051 status
= class_register(&gpio_class
);
1055 /* Scan and register the gpio_chips which registered very
1056 * early (e.g. before the class_register above was called).
1058 * We run before arch_initcall() so chip->dev nodes can have
1059 * registered, and so arch_initcall() can always gpio_export().
1061 spin_lock_irqsave(&gpio_lock
, flags
);
1062 list_for_each_entry(chip
, &gpio_chips
, list
) {
1063 if (!chip
|| chip
->exported
)
1066 spin_unlock_irqrestore(&gpio_lock
, flags
);
1067 status
= gpiochip_export(chip
);
1068 spin_lock_irqsave(&gpio_lock
, flags
);
1070 spin_unlock_irqrestore(&gpio_lock
, flags
);
1075 postcore_initcall(gpiolib_sysfs_init
);
1078 static inline int gpiochip_export(struct gpio_chip
*chip
)
1083 static inline void gpiochip_unexport(struct gpio_chip
*chip
)
1087 static inline int gpiod_export(struct gpio_desc
*desc
,
1088 bool direction_may_change
)
1093 static inline int gpiod_export_link(struct device
*dev
, const char *name
,
1094 struct gpio_desc
*desc
)
1099 static inline int gpiod_sysfs_set_active_low(struct gpio_desc
*desc
, int value
)
1104 static inline void gpiod_unexport(struct gpio_desc
*desc
)
1108 #endif /* CONFIG_GPIO_SYSFS */
1111 * Add a new chip to the global chips list, keeping the list of chips sorted
1114 * Return -EBUSY if the new chip overlaps with some other chip's integer
1117 static int gpiochip_add_to_list(struct gpio_chip
*chip
)
1119 struct list_head
*pos
= &gpio_chips
;
1120 struct gpio_chip
*_chip
;
1123 /* find where to insert our chip */
1124 list_for_each(pos
, &gpio_chips
) {
1125 _chip
= list_entry(pos
, struct gpio_chip
, list
);
1126 /* shall we insert before _chip? */
1127 if (_chip
->base
>= chip
->base
+ chip
->ngpio
)
1131 /* are we stepping on the chip right before? */
1132 if (pos
!= &gpio_chips
&& pos
->prev
!= &gpio_chips
) {
1133 _chip
= list_entry(pos
->prev
, struct gpio_chip
, list
);
1134 if (_chip
->base
+ _chip
->ngpio
> chip
->base
) {
1136 "GPIO integer space overlap, cannot add chip\n");
1142 list_add_tail(&chip
->list
, pos
);
1148 * gpiochip_add() - register a gpio_chip
1149 * @chip: the chip to register, with chip->base initialized
1150 * Context: potentially before irqs or kmalloc will work
1152 * Returns a negative errno if the chip can't be registered, such as
1153 * because the chip->base is invalid or already associated with a
1154 * different chip. Otherwise it returns zero as a success code.
1156 * When gpiochip_add() is called very early during boot, so that GPIOs
1157 * can be freely used, the chip->dev device must be registered before
1158 * the gpio framework's arch_initcall(). Otherwise sysfs initialization
1159 * for GPIOs will fail rudely.
1161 * If chip->base is negative, this requests dynamic assignment of
1162 * a range of valid GPIOs.
1164 int gpiochip_add(struct gpio_chip
*chip
)
1166 unsigned long flags
;
1169 int base
= chip
->base
;
1171 if ((!gpio_is_valid(base
) || !gpio_is_valid(base
+ chip
->ngpio
- 1))
1177 spin_lock_irqsave(&gpio_lock
, flags
);
1180 base
= gpiochip_find_base(chip
->ngpio
);
1188 status
= gpiochip_add_to_list(chip
);
1191 chip
->desc
= &gpio_desc
[chip
->base
];
1193 for (id
= 0; id
< chip
->ngpio
; id
++) {
1194 struct gpio_desc
*desc
= &chip
->desc
[id
];
1197 /* REVISIT: most hardware initializes GPIOs as
1198 * inputs (often with pullups enabled) so power
1199 * usage is minimized. Linux code should set the
1200 * gpio direction first thing; but until it does,
1201 * and in case chip->get_direction is not set,
1202 * we may expose the wrong direction in sysfs.
1204 desc
->flags
= !chip
->direction_input
1205 ? (1 << FLAG_IS_OUT
)
1210 #ifdef CONFIG_PINCTRL
1211 INIT_LIST_HEAD(&chip
->pin_ranges
);
1214 of_gpiochip_add(chip
);
1217 spin_unlock_irqrestore(&gpio_lock
, flags
);
1222 status
= gpiochip_export(chip
);
1226 pr_debug("gpiochip_add: registered GPIOs %d to %d on device: %s\n",
1227 chip
->base
, chip
->base
+ chip
->ngpio
- 1,
1228 chip
->label
? : "generic");
1232 /* failures here can mean systems won't boot... */
1233 pr_err("gpiochip_add: gpios %d..%d (%s) failed to register\n",
1234 chip
->base
, chip
->base
+ chip
->ngpio
- 1,
1235 chip
->label
? : "generic");
1238 EXPORT_SYMBOL_GPL(gpiochip_add
);
1241 * gpiochip_remove() - unregister a gpio_chip
1242 * @chip: the chip to unregister
1244 * A gpio_chip with any GPIOs still requested may not be removed.
1246 int gpiochip_remove(struct gpio_chip
*chip
)
1248 unsigned long flags
;
1252 spin_lock_irqsave(&gpio_lock
, flags
);
1254 gpiochip_remove_pin_ranges(chip
);
1255 of_gpiochip_remove(chip
);
1257 for (id
= 0; id
< chip
->ngpio
; id
++) {
1258 if (test_bit(FLAG_REQUESTED
, &chip
->desc
[id
].flags
)) {
1264 for (id
= 0; id
< chip
->ngpio
; id
++)
1265 chip
->desc
[id
].chip
= NULL
;
1267 list_del(&chip
->list
);
1270 spin_unlock_irqrestore(&gpio_lock
, flags
);
1273 gpiochip_unexport(chip
);
1277 EXPORT_SYMBOL_GPL(gpiochip_remove
);
1280 * gpiochip_find() - iterator for locating a specific gpio_chip
1281 * @data: data to pass to match function
1282 * @callback: Callback function to check gpio_chip
1284 * Similar to bus_find_device. It returns a reference to a gpio_chip as
1285 * determined by a user supplied @match callback. The callback should return
1286 * 0 if the device doesn't match and non-zero if it does. If the callback is
1287 * non-zero, this function will return to the caller and not iterate over any
1290 struct gpio_chip
*gpiochip_find(void *data
,
1291 int (*match
)(struct gpio_chip
*chip
,
1294 struct gpio_chip
*chip
;
1295 unsigned long flags
;
1297 spin_lock_irqsave(&gpio_lock
, flags
);
1298 list_for_each_entry(chip
, &gpio_chips
, list
)
1299 if (match(chip
, data
))
1303 if (&chip
->list
== &gpio_chips
)
1305 spin_unlock_irqrestore(&gpio_lock
, flags
);
1309 EXPORT_SYMBOL_GPL(gpiochip_find
);
1311 #ifdef CONFIG_PINCTRL
1314 * gpiochip_add_pin_range() - add a range for GPIO <-> pin mapping
1315 * @chip: the gpiochip to add the range for
1316 * @pinctrl_name: the dev_name() of the pin controller to map to
1317 * @gpio_offset: the start offset in the current gpio_chip number space
1318 * @pin_offset: the start offset in the pin controller number space
1319 * @npins: the number of pins from the offset of each pin space (GPIO and
1320 * pin controller) to accumulate in this range
1322 int gpiochip_add_pin_range(struct gpio_chip
*chip
, const char *pinctl_name
,
1323 unsigned int gpio_offset
, unsigned int pin_offset
,
1326 struct gpio_pin_range
*pin_range
;
1329 pin_range
= kzalloc(sizeof(*pin_range
), GFP_KERNEL
);
1331 pr_err("%s: GPIO chip: failed to allocate pin ranges\n",
1336 /* Use local offset as range ID */
1337 pin_range
->range
.id
= gpio_offset
;
1338 pin_range
->range
.gc
= chip
;
1339 pin_range
->range
.name
= chip
->label
;
1340 pin_range
->range
.base
= chip
->base
+ gpio_offset
;
1341 pin_range
->range
.pin_base
= pin_offset
;
1342 pin_range
->range
.npins
= npins
;
1343 pin_range
->pctldev
= pinctrl_find_and_add_gpio_range(pinctl_name
,
1345 if (IS_ERR(pin_range
->pctldev
)) {
1346 ret
= PTR_ERR(pin_range
->pctldev
);
1347 pr_err("%s: GPIO chip: could not create pin range\n",
1352 pr_debug("GPIO chip %s: created GPIO range %d->%d ==> %s PIN %d->%d\n",
1353 chip
->label
, gpio_offset
, gpio_offset
+ npins
- 1,
1355 pin_offset
, pin_offset
+ npins
- 1);
1357 list_add_tail(&pin_range
->node
, &chip
->pin_ranges
);
1361 EXPORT_SYMBOL_GPL(gpiochip_add_pin_range
);
1364 * gpiochip_remove_pin_ranges() - remove all the GPIO <-> pin mappings
1365 * @chip: the chip to remove all the mappings for
1367 void gpiochip_remove_pin_ranges(struct gpio_chip
*chip
)
1369 struct gpio_pin_range
*pin_range
, *tmp
;
1371 list_for_each_entry_safe(pin_range
, tmp
, &chip
->pin_ranges
, node
) {
1372 list_del(&pin_range
->node
);
1373 pinctrl_remove_gpio_range(pin_range
->pctldev
,
1378 EXPORT_SYMBOL_GPL(gpiochip_remove_pin_ranges
);
1380 #endif /* CONFIG_PINCTRL */
1382 /* These "optional" allocation calls help prevent drivers from stomping
1383 * on each other, and help provide better diagnostics in debugfs.
1384 * They're called even less than the "set direction" calls.
1386 static int gpiod_request(struct gpio_desc
*desc
, const char *label
)
1388 struct gpio_chip
*chip
;
1389 int status
= -EPROBE_DEFER
;
1390 unsigned long flags
;
1392 spin_lock_irqsave(&gpio_lock
, flags
);
1402 if (!try_module_get(chip
->owner
))
1405 /* NOTE: gpio_request() can be called in early boot,
1406 * before IRQs are enabled, for non-sleeping (SOC) GPIOs.
1409 if (test_and_set_bit(FLAG_REQUESTED
, &desc
->flags
) == 0) {
1410 desc_set_label(desc
, label
? : "?");
1414 module_put(chip
->owner
);
1418 if (chip
->request
) {
1419 /* chip->request may sleep */
1420 spin_unlock_irqrestore(&gpio_lock
, flags
);
1421 status
= chip
->request(chip
, gpio_chip_hwgpio(desc
));
1422 spin_lock_irqsave(&gpio_lock
, flags
);
1425 desc_set_label(desc
, NULL
);
1426 module_put(chip
->owner
);
1427 clear_bit(FLAG_REQUESTED
, &desc
->flags
);
1431 if (chip
->get_direction
) {
1432 /* chip->get_direction may sleep */
1433 spin_unlock_irqrestore(&gpio_lock
, flags
);
1434 gpiod_get_direction(desc
);
1435 spin_lock_irqsave(&gpio_lock
, flags
);
1439 pr_debug("_gpio_request: gpio-%d (%s) status %d\n",
1440 desc
? desc_to_gpio(desc
) : -1,
1441 label
? : "?", status
);
1442 spin_unlock_irqrestore(&gpio_lock
, flags
);
1446 int gpio_request(unsigned gpio
, const char *label
)
1448 return gpiod_request(gpio_to_desc(gpio
), label
);
1450 EXPORT_SYMBOL_GPL(gpio_request
);
1452 static void gpiod_free(struct gpio_desc
*desc
)
1454 unsigned long flags
;
1455 struct gpio_chip
*chip
;
1460 WARN_ON(extra_checks
);
1464 gpiod_unexport(desc
);
1466 spin_lock_irqsave(&gpio_lock
, flags
);
1469 if (chip
&& test_bit(FLAG_REQUESTED
, &desc
->flags
)) {
1471 spin_unlock_irqrestore(&gpio_lock
, flags
);
1472 might_sleep_if(chip
->can_sleep
);
1473 chip
->free(chip
, gpio_chip_hwgpio(desc
));
1474 spin_lock_irqsave(&gpio_lock
, flags
);
1476 desc_set_label(desc
, NULL
);
1477 module_put(desc
->chip
->owner
);
1478 clear_bit(FLAG_ACTIVE_LOW
, &desc
->flags
);
1479 clear_bit(FLAG_REQUESTED
, &desc
->flags
);
1480 clear_bit(FLAG_OPEN_DRAIN
, &desc
->flags
);
1481 clear_bit(FLAG_OPEN_SOURCE
, &desc
->flags
);
1483 WARN_ON(extra_checks
);
1485 spin_unlock_irqrestore(&gpio_lock
, flags
);
1488 void gpio_free(unsigned gpio
)
1490 gpiod_free(gpio_to_desc(gpio
));
1492 EXPORT_SYMBOL_GPL(gpio_free
);
1495 * gpio_request_one - request a single GPIO with initial configuration
1496 * @gpio: the GPIO number
1497 * @flags: GPIO configuration as specified by GPIOF_*
1498 * @label: a literal description string of this GPIO
1500 int gpio_request_one(unsigned gpio
, unsigned long flags
, const char *label
)
1502 struct gpio_desc
*desc
;
1505 desc
= gpio_to_desc(gpio
);
1507 err
= gpiod_request(desc
, label
);
1511 if (flags
& GPIOF_OPEN_DRAIN
)
1512 set_bit(FLAG_OPEN_DRAIN
, &desc
->flags
);
1514 if (flags
& GPIOF_OPEN_SOURCE
)
1515 set_bit(FLAG_OPEN_SOURCE
, &desc
->flags
);
1517 if (flags
& GPIOF_DIR_IN
)
1518 err
= gpiod_direction_input(desc
);
1520 err
= gpiod_direction_output(desc
,
1521 (flags
& GPIOF_INIT_HIGH
) ? 1 : 0);
1526 if (flags
& GPIOF_EXPORT
) {
1527 err
= gpiod_export(desc
, flags
& GPIOF_EXPORT_CHANGEABLE
);
1538 EXPORT_SYMBOL_GPL(gpio_request_one
);
1541 * gpio_request_array - request multiple GPIOs in a single call
1542 * @array: array of the 'struct gpio'
1543 * @num: how many GPIOs in the array
1545 int gpio_request_array(const struct gpio
*array
, size_t num
)
1549 for (i
= 0; i
< num
; i
++, array
++) {
1550 err
= gpio_request_one(array
->gpio
, array
->flags
, array
->label
);
1558 gpio_free((--array
)->gpio
);
1561 EXPORT_SYMBOL_GPL(gpio_request_array
);
1564 * gpio_free_array - release multiple GPIOs in a single call
1565 * @array: array of the 'struct gpio'
1566 * @num: how many GPIOs in the array
1568 void gpio_free_array(const struct gpio
*array
, size_t num
)
1571 gpio_free((array
++)->gpio
);
1573 EXPORT_SYMBOL_GPL(gpio_free_array
);
1576 * gpiochip_is_requested - return string iff signal was requested
1577 * @chip: controller managing the signal
1578 * @offset: of signal within controller's 0..(ngpio - 1) range
1580 * Returns NULL if the GPIO is not currently requested, else a string.
1581 * If debugfs support is enabled, the string returned is the label passed
1582 * to gpio_request(); otherwise it is a meaningless constant.
1584 * This function is for use by GPIO controller drivers. The label can
1585 * help with diagnostics, and knowing that the signal is used as a GPIO
1586 * can help avoid accidentally multiplexing it to another controller.
1588 const char *gpiochip_is_requested(struct gpio_chip
*chip
, unsigned offset
)
1590 struct gpio_desc
*desc
;
1592 if (!GPIO_OFFSET_VALID(chip
, offset
))
1595 desc
= &chip
->desc
[offset
];
1597 if (test_bit(FLAG_REQUESTED
, &desc
->flags
) == 0)
1599 #ifdef CONFIG_DEBUG_FS
1605 EXPORT_SYMBOL_GPL(gpiochip_is_requested
);
1608 /* Drivers MUST set GPIO direction before making get/set calls. In
1609 * some cases this is done in early boot, before IRQs are enabled.
1611 * As a rule these aren't called more than once (except for drivers
1612 * using the open-drain emulation idiom) so these are natural places
1613 * to accumulate extra debugging checks. Note that we can't (yet)
1614 * rely on gpio_request() having been called beforehand.
1617 static int gpiod_direction_input(struct gpio_desc
*desc
)
1619 unsigned long flags
;
1620 struct gpio_chip
*chip
;
1621 int status
= -EINVAL
;
1624 spin_lock_irqsave(&gpio_lock
, flags
);
1629 if (!chip
|| !chip
->get
|| !chip
->direction_input
)
1631 status
= gpio_ensure_requested(desc
);
1635 /* now we know the gpio is valid and chip won't vanish */
1637 spin_unlock_irqrestore(&gpio_lock
, flags
);
1639 might_sleep_if(chip
->can_sleep
);
1641 offset
= gpio_chip_hwgpio(desc
);
1643 status
= chip
->request(chip
, offset
);
1645 pr_debug("GPIO-%d: chip request fail, %d\n",
1646 desc_to_gpio(desc
), status
);
1647 /* and it's not available to anyone else ...
1648 * gpio_request() is the fully clean solution.
1654 status
= chip
->direction_input(chip
, offset
);
1656 clear_bit(FLAG_IS_OUT
, &desc
->flags
);
1658 trace_gpio_direction(desc_to_gpio(desc
), 1, status
);
1662 spin_unlock_irqrestore(&gpio_lock
, flags
);
1666 gpio
= desc_to_gpio(desc
);
1667 pr_debug("%s: gpio-%d status %d\n",
1668 __func__
, gpio
, status
);
1673 int gpio_direction_input(unsigned gpio
)
1675 return gpiod_direction_input(gpio_to_desc(gpio
));
1677 EXPORT_SYMBOL_GPL(gpio_direction_input
);
1679 static int gpiod_direction_output(struct gpio_desc
*desc
, int value
)
1681 unsigned long flags
;
1682 struct gpio_chip
*chip
;
1683 int status
= -EINVAL
;
1686 /* Open drain pin should not be driven to 1 */
1687 if (value
&& test_bit(FLAG_OPEN_DRAIN
, &desc
->flags
))
1688 return gpiod_direction_input(desc
);
1690 /* Open source pin should not be driven to 0 */
1691 if (!value
&& test_bit(FLAG_OPEN_SOURCE
, &desc
->flags
))
1692 return gpiod_direction_input(desc
);
1694 spin_lock_irqsave(&gpio_lock
, flags
);
1699 if (!chip
|| !chip
->set
|| !chip
->direction_output
)
1701 status
= gpio_ensure_requested(desc
);
1705 /* now we know the gpio is valid and chip won't vanish */
1707 spin_unlock_irqrestore(&gpio_lock
, flags
);
1709 might_sleep_if(chip
->can_sleep
);
1711 offset
= gpio_chip_hwgpio(desc
);
1713 status
= chip
->request(chip
, offset
);
1715 pr_debug("GPIO-%d: chip request fail, %d\n",
1716 desc_to_gpio(desc
), status
);
1717 /* and it's not available to anyone else ...
1718 * gpio_request() is the fully clean solution.
1724 status
= chip
->direction_output(chip
, offset
, value
);
1726 set_bit(FLAG_IS_OUT
, &desc
->flags
);
1727 trace_gpio_value(desc_to_gpio(desc
), 0, value
);
1728 trace_gpio_direction(desc_to_gpio(desc
), 0, status
);
1732 spin_unlock_irqrestore(&gpio_lock
, flags
);
1736 gpio
= desc_to_gpio(desc
);
1737 pr_debug("%s: gpio-%d status %d\n",
1738 __func__
, gpio
, status
);
1743 int gpio_direction_output(unsigned gpio
, int value
)
1745 return gpiod_direction_output(gpio_to_desc(gpio
), value
);
1747 EXPORT_SYMBOL_GPL(gpio_direction_output
);
1750 * gpio_set_debounce - sets @debounce time for a @gpio
1751 * @gpio: the gpio to set debounce time
1752 * @debounce: debounce time is microseconds
1754 static int gpiod_set_debounce(struct gpio_desc
*desc
, unsigned debounce
)
1756 unsigned long flags
;
1757 struct gpio_chip
*chip
;
1758 int status
= -EINVAL
;
1761 spin_lock_irqsave(&gpio_lock
, flags
);
1766 if (!chip
|| !chip
->set
|| !chip
->set_debounce
)
1769 status
= gpio_ensure_requested(desc
);
1773 /* now we know the gpio is valid and chip won't vanish */
1775 spin_unlock_irqrestore(&gpio_lock
, flags
);
1777 might_sleep_if(chip
->can_sleep
);
1779 offset
= gpio_chip_hwgpio(desc
);
1780 return chip
->set_debounce(chip
, offset
, debounce
);
1783 spin_unlock_irqrestore(&gpio_lock
, flags
);
1787 gpio
= desc_to_gpio(desc
);
1788 pr_debug("%s: gpio-%d status %d\n",
1789 __func__
, gpio
, status
);
1795 int gpio_set_debounce(unsigned gpio
, unsigned debounce
)
1797 return gpiod_set_debounce(gpio_to_desc(gpio
), debounce
);
1799 EXPORT_SYMBOL_GPL(gpio_set_debounce
);
1801 /* I/O calls are only valid after configuration completed; the relevant
1802 * "is this a valid GPIO" error checks should already have been done.
1804 * "Get" operations are often inlinable as reading a pin value register,
1805 * and masking the relevant bit in that register.
1807 * When "set" operations are inlinable, they involve writing that mask to
1808 * one register to set a low value, or a different register to set it high.
1809 * Otherwise locking is needed, so there may be little value to inlining.
1811 *------------------------------------------------------------------------
1813 * IMPORTANT!!! The hot paths -- get/set value -- assume that callers
1814 * have requested the GPIO. That can include implicit requesting by
1815 * a direction setting call. Marking a gpio as requested locks its chip
1816 * in memory, guaranteeing that these table lookups need no more locking
1817 * and that gpiochip_remove() will fail.
1819 * REVISIT when debugging, consider adding some instrumentation to ensure
1820 * that the GPIO was actually requested.
1824 * __gpio_get_value() - return a gpio's value
1825 * @gpio: gpio whose value will be returned
1828 * This is used directly or indirectly to implement gpio_get_value().
1829 * It returns the zero or nonzero value provided by the associated
1830 * gpio_chip.get() method; or zero if no such method is provided.
1832 static int gpiod_get_value(struct gpio_desc
*desc
)
1834 struct gpio_chip
*chip
;
1839 offset
= gpio_chip_hwgpio(desc
);
1840 /* Should be using gpio_get_value_cansleep() */
1841 WARN_ON(chip
->can_sleep
);
1842 value
= chip
->get
? chip
->get(chip
, offset
) : 0;
1843 trace_gpio_value(desc_to_gpio(desc
), 1, value
);
1847 int __gpio_get_value(unsigned gpio
)
1849 return gpiod_get_value(gpio_to_desc(gpio
));
1851 EXPORT_SYMBOL_GPL(__gpio_get_value
);
1854 * _gpio_set_open_drain_value() - Set the open drain gpio's value.
1855 * @gpio: Gpio whose state need to be set.
1857 * @value: Non-zero for setting it HIGH otherise it will set to LOW.
1859 static void _gpio_set_open_drain_value(struct gpio_desc
*desc
, int value
)
1862 struct gpio_chip
*chip
= desc
->chip
;
1863 int offset
= gpio_chip_hwgpio(desc
);
1866 err
= chip
->direction_input(chip
, offset
);
1868 clear_bit(FLAG_IS_OUT
, &desc
->flags
);
1870 err
= chip
->direction_output(chip
, offset
, 0);
1872 set_bit(FLAG_IS_OUT
, &desc
->flags
);
1874 trace_gpio_direction(desc_to_gpio(desc
), value
, err
);
1876 pr_err("%s: Error in set_value for open drain gpio%d err %d\n",
1877 __func__
, desc_to_gpio(desc
), err
);
1881 * _gpio_set_open_source() - Set the open source gpio's value.
1882 * @gpio: Gpio whose state need to be set.
1884 * @value: Non-zero for setting it HIGH otherise it will set to LOW.
1886 static void _gpio_set_open_source_value(struct gpio_desc
*desc
, int value
)
1889 struct gpio_chip
*chip
= desc
->chip
;
1890 int offset
= gpio_chip_hwgpio(desc
);
1893 err
= chip
->direction_output(chip
, offset
, 1);
1895 set_bit(FLAG_IS_OUT
, &desc
->flags
);
1897 err
= chip
->direction_input(chip
, offset
);
1899 clear_bit(FLAG_IS_OUT
, &desc
->flags
);
1901 trace_gpio_direction(desc_to_gpio(desc
), !value
, err
);
1903 pr_err("%s: Error in set_value for open source gpio%d err %d\n",
1904 __func__
, desc_to_gpio(desc
), err
);
1908 * __gpio_set_value() - assign a gpio's value
1909 * @gpio: gpio whose value will be assigned
1910 * @value: value to assign
1913 * This is used directly or indirectly to implement gpio_set_value().
1914 * It invokes the associated gpio_chip.set() method.
1916 static void gpiod_set_value(struct gpio_desc
*desc
, int value
)
1918 struct gpio_chip
*chip
;
1921 /* Should be using gpio_set_value_cansleep() */
1922 WARN_ON(chip
->can_sleep
);
1923 trace_gpio_value(desc_to_gpio(desc
), 0, value
);
1924 if (test_bit(FLAG_OPEN_DRAIN
, &desc
->flags
))
1925 _gpio_set_open_drain_value(desc
, value
);
1926 else if (test_bit(FLAG_OPEN_SOURCE
, &desc
->flags
))
1927 _gpio_set_open_source_value(desc
, value
);
1929 chip
->set(chip
, gpio_chip_hwgpio(desc
), value
);
1932 void __gpio_set_value(unsigned gpio
, int value
)
1934 return gpiod_set_value(gpio_to_desc(gpio
), value
);
1936 EXPORT_SYMBOL_GPL(__gpio_set_value
);
1939 * __gpio_cansleep() - report whether gpio value access will sleep
1940 * @gpio: gpio in question
1943 * This is used directly or indirectly to implement gpio_cansleep(). It
1944 * returns nonzero if access reading or writing the GPIO value can sleep.
1946 static int gpiod_cansleep(struct gpio_desc
*desc
)
1948 /* only call this on GPIOs that are valid! */
1949 return desc
->chip
->can_sleep
;
1952 int __gpio_cansleep(unsigned gpio
)
1954 return gpiod_cansleep(gpio_to_desc(gpio
));
1956 EXPORT_SYMBOL_GPL(__gpio_cansleep
);
1959 * __gpio_to_irq() - return the IRQ corresponding to a GPIO
1960 * @gpio: gpio whose IRQ will be returned (already requested)
1963 * This is used directly or indirectly to implement gpio_to_irq().
1964 * It returns the number of the IRQ signaled by this (input) GPIO,
1965 * or a negative errno.
1967 static int gpiod_to_irq(struct gpio_desc
*desc
)
1969 struct gpio_chip
*chip
;
1973 offset
= gpio_chip_hwgpio(desc
);
1974 return chip
->to_irq
? chip
->to_irq(chip
, offset
) : -ENXIO
;
1977 int __gpio_to_irq(unsigned gpio
)
1979 return gpiod_to_irq(gpio_to_desc(gpio
));
1981 EXPORT_SYMBOL_GPL(__gpio_to_irq
);
1984 /* There's no value in making it easy to inline GPIO calls that may sleep.
1985 * Common examples include ones connected to I2C or SPI chips.
1988 static int gpiod_get_value_cansleep(struct gpio_desc
*desc
)
1990 struct gpio_chip
*chip
;
1994 might_sleep_if(extra_checks
);
1996 offset
= gpio_chip_hwgpio(desc
);
1997 value
= chip
->get
? chip
->get(chip
, offset
) : 0;
1998 trace_gpio_value(desc_to_gpio(desc
), 1, value
);
2002 int gpio_get_value_cansleep(unsigned gpio
)
2004 return gpiod_get_value_cansleep(gpio_to_desc(gpio
));
2006 EXPORT_SYMBOL_GPL(gpio_get_value_cansleep
);
2008 static void gpiod_set_value_cansleep(struct gpio_desc
*desc
, int value
)
2010 struct gpio_chip
*chip
;
2012 might_sleep_if(extra_checks
);
2014 trace_gpio_value(desc_to_gpio(desc
), 0, value
);
2015 if (test_bit(FLAG_OPEN_DRAIN
, &desc
->flags
))
2016 _gpio_set_open_drain_value(desc
, value
);
2017 else if (test_bit(FLAG_OPEN_SOURCE
, &desc
->flags
))
2018 _gpio_set_open_source_value(desc
, value
);
2020 chip
->set(chip
, gpio_chip_hwgpio(desc
), value
);
2023 void gpio_set_value_cansleep(unsigned gpio
, int value
)
2025 return gpiod_set_value_cansleep(gpio_to_desc(gpio
), value
);
2027 EXPORT_SYMBOL_GPL(gpio_set_value_cansleep
);
2029 #ifdef CONFIG_DEBUG_FS
2031 static void gpiolib_dbg_show(struct seq_file
*s
, struct gpio_chip
*chip
)
2034 unsigned gpio
= chip
->base
;
2035 struct gpio_desc
*gdesc
= &chip
->desc
[0];
2038 for (i
= 0; i
< chip
->ngpio
; i
++, gpio
++, gdesc
++) {
2039 if (!test_bit(FLAG_REQUESTED
, &gdesc
->flags
))
2042 gpiod_get_direction(gdesc
);
2043 is_out
= test_bit(FLAG_IS_OUT
, &gdesc
->flags
);
2044 seq_printf(s
, " gpio-%-3d (%-20.20s) %s %s",
2046 is_out
? "out" : "in ",
2048 ? (chip
->get(chip
, i
) ? "hi" : "lo")
2050 seq_printf(s
, "\n");
2054 static void *gpiolib_seq_start(struct seq_file
*s
, loff_t
*pos
)
2056 unsigned long flags
;
2057 struct gpio_chip
*chip
= NULL
;
2058 loff_t index
= *pos
;
2062 spin_lock_irqsave(&gpio_lock
, flags
);
2063 list_for_each_entry(chip
, &gpio_chips
, list
)
2065 spin_unlock_irqrestore(&gpio_lock
, flags
);
2068 spin_unlock_irqrestore(&gpio_lock
, flags
);
2073 static void *gpiolib_seq_next(struct seq_file
*s
, void *v
, loff_t
*pos
)
2075 unsigned long flags
;
2076 struct gpio_chip
*chip
= v
;
2079 spin_lock_irqsave(&gpio_lock
, flags
);
2080 if (list_is_last(&chip
->list
, &gpio_chips
))
2083 ret
= list_entry(chip
->list
.next
, struct gpio_chip
, list
);
2084 spin_unlock_irqrestore(&gpio_lock
, flags
);
2092 static void gpiolib_seq_stop(struct seq_file
*s
, void *v
)
2096 static int gpiolib_seq_show(struct seq_file
*s
, void *v
)
2098 struct gpio_chip
*chip
= v
;
2101 seq_printf(s
, "%sGPIOs %d-%d", (char *)s
->private,
2102 chip
->base
, chip
->base
+ chip
->ngpio
- 1);
2105 seq_printf(s
, ", %s/%s", dev
->bus
? dev
->bus
->name
: "no-bus",
2108 seq_printf(s
, ", %s", chip
->label
);
2109 if (chip
->can_sleep
)
2110 seq_printf(s
, ", can sleep");
2111 seq_printf(s
, ":\n");
2114 chip
->dbg_show(s
, chip
);
2116 gpiolib_dbg_show(s
, chip
);
2121 static const struct seq_operations gpiolib_seq_ops
= {
2122 .start
= gpiolib_seq_start
,
2123 .next
= gpiolib_seq_next
,
2124 .stop
= gpiolib_seq_stop
,
2125 .show
= gpiolib_seq_show
,
2128 static int gpiolib_open(struct inode
*inode
, struct file
*file
)
2130 return seq_open(file
, &gpiolib_seq_ops
);
2133 static const struct file_operations gpiolib_operations
= {
2134 .owner
= THIS_MODULE
,
2135 .open
= gpiolib_open
,
2137 .llseek
= seq_lseek
,
2138 .release
= seq_release
,
2141 static int __init
gpiolib_debugfs_init(void)
2143 /* /sys/kernel/debug/gpio */
2144 (void) debugfs_create_file("gpio", S_IFREG
| S_IRUGO
,
2145 NULL
, NULL
, &gpiolib_operations
);
2148 subsys_initcall(gpiolib_debugfs_init
);
2150 #endif /* DEBUG_FS */