blob: fd4d9423f6e6aebc3e1c89c2cf11adbeb14e6ee2 [file] [log] [blame]
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +09001#include <linux/idr.h>
2#include <linux/mutex.h>
3#include <linux/device.h>
4#include <linux/sysfs.h>
5#include <linux/gpio/consumer.h>
6#include <linux/gpio/driver.h>
7#include <linux/interrupt.h>
8#include <linux/kdev_t.h>
9
10#include "gpiolib.h"
11
12static DEFINE_IDR(dirent_idr);
13
14
15/* lock protects against unexport_gpio() being called while
16 * sysfs files are active.
17 */
18static DEFINE_MUTEX(sysfs_lock);
19
20/*
21 * /sys/class/gpio/gpioN... only for GPIOs that are exported
22 * /direction
23 * * MAY BE OMITTED if kernel won't allow direction changes
24 * * is read/write as "in" or "out"
25 * * may also be written as "high" or "low", initializing
26 * output value as specified ("out" implies "low")
27 * /value
28 * * always readable, subject to hardware behavior
29 * * may be writable, as zero/nonzero
30 * /edge
31 * * configures behavior of poll(2) on /value
32 * * available only if pin can generate IRQs on input
33 * * is read/write as "none", "falling", "rising", or "both"
34 * /active_low
35 * * configures polarity of /value
36 * * is read/write as zero/nonzero
37 * * also affects existing and subsequent "falling" and "rising"
38 * /edge configuration
39 */
40
41static ssize_t gpio_direction_show(struct device *dev,
42 struct device_attribute *attr, char *buf)
43{
Alexandre Courbot8e53b0f2014-11-25 17:16:31 +090044 struct gpio_desc *desc = dev_get_drvdata(dev);
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +090045 ssize_t status;
46
47 mutex_lock(&sysfs_lock);
48
49 if (!test_bit(FLAG_EXPORT, &desc->flags)) {
50 status = -EIO;
51 } else {
52 gpiod_get_direction(desc);
53 status = sprintf(buf, "%s\n",
54 test_bit(FLAG_IS_OUT, &desc->flags)
55 ? "out" : "in");
56 }
57
58 mutex_unlock(&sysfs_lock);
59 return status;
60}
61
62static ssize_t gpio_direction_store(struct device *dev,
63 struct device_attribute *attr, const char *buf, size_t size)
64{
65 struct gpio_desc *desc = dev_get_drvdata(dev);
66 ssize_t status;
67
68 mutex_lock(&sysfs_lock);
69
70 if (!test_bit(FLAG_EXPORT, &desc->flags))
71 status = -EIO;
72 else if (sysfs_streq(buf, "high"))
73 status = gpiod_direction_output_raw(desc, 1);
74 else if (sysfs_streq(buf, "out") || sysfs_streq(buf, "low"))
75 status = gpiod_direction_output_raw(desc, 0);
76 else if (sysfs_streq(buf, "in"))
77 status = gpiod_direction_input(desc);
78 else
79 status = -EINVAL;
80
81 mutex_unlock(&sysfs_lock);
82 return status ? : size;
83}
84
85static /* const */ DEVICE_ATTR(direction, 0644,
86 gpio_direction_show, gpio_direction_store);
87
88static ssize_t gpio_value_show(struct device *dev,
89 struct device_attribute *attr, char *buf)
90{
91 struct gpio_desc *desc = dev_get_drvdata(dev);
92 ssize_t status;
93
94 mutex_lock(&sysfs_lock);
95
96 if (!test_bit(FLAG_EXPORT, &desc->flags))
97 status = -EIO;
98 else
99 status = sprintf(buf, "%d\n", gpiod_get_value_cansleep(desc));
100
101 mutex_unlock(&sysfs_lock);
102 return status;
103}
104
105static ssize_t gpio_value_store(struct device *dev,
106 struct device_attribute *attr, const char *buf, size_t size)
107{
108 struct gpio_desc *desc = dev_get_drvdata(dev);
109 ssize_t status;
110
111 mutex_lock(&sysfs_lock);
112
113 if (!test_bit(FLAG_EXPORT, &desc->flags))
114 status = -EIO;
115 else if (!test_bit(FLAG_IS_OUT, &desc->flags))
116 status = -EPERM;
117 else {
118 long value;
119
120 status = kstrtol(buf, 0, &value);
121 if (status == 0) {
122 gpiod_set_value_cansleep(desc, value);
123 status = size;
124 }
125 }
126
127 mutex_unlock(&sysfs_lock);
128 return status;
129}
130
Johan Hovold0915e6f2015-01-13 13:00:05 +0100131static DEVICE_ATTR(value, 0644,
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900132 gpio_value_show, gpio_value_store);
133
134static irqreturn_t gpio_sysfs_irq(int irq, void *priv)
135{
136 struct kernfs_node *value_sd = priv;
137
138 sysfs_notify_dirent(value_sd);
139 return IRQ_HANDLED;
140}
141
142static int gpio_setup_irq(struct gpio_desc *desc, struct device *dev,
143 unsigned long gpio_flags)
144{
145 struct kernfs_node *value_sd;
146 unsigned long irq_flags;
147 int ret, irq, id;
148
149 if ((desc->flags & GPIO_TRIGGER_MASK) == gpio_flags)
150 return 0;
151
152 irq = gpiod_to_irq(desc);
153 if (irq < 0)
154 return -EIO;
155
156 id = desc->flags >> ID_SHIFT;
157 value_sd = idr_find(&dirent_idr, id);
158 if (value_sd)
159 free_irq(irq, value_sd);
160
161 desc->flags &= ~GPIO_TRIGGER_MASK;
162
163 if (!gpio_flags) {
Alexandre Courbote3a2e872014-10-23 17:27:07 +0900164 gpiochip_unlock_as_irq(desc->chip, gpio_chip_hwgpio(desc));
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900165 ret = 0;
166 goto free_id;
167 }
168
169 irq_flags = IRQF_SHARED;
170 if (test_bit(FLAG_TRIG_FALL, &gpio_flags))
171 irq_flags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ?
172 IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING;
173 if (test_bit(FLAG_TRIG_RISE, &gpio_flags))
174 irq_flags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ?
175 IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING;
176
177 if (!value_sd) {
178 value_sd = sysfs_get_dirent(dev->kobj.sd, "value");
179 if (!value_sd) {
180 ret = -ENODEV;
181 goto err_out;
182 }
183
184 ret = idr_alloc(&dirent_idr, value_sd, 1, 0, GFP_KERNEL);
185 if (ret < 0)
186 goto free_sd;
187 id = ret;
188
189 desc->flags &= GPIO_FLAGS_MASK;
190 desc->flags |= (unsigned long)id << ID_SHIFT;
191
192 if (desc->flags >> ID_SHIFT != id) {
193 ret = -ERANGE;
194 goto free_id;
195 }
196 }
197
198 ret = request_any_context_irq(irq, gpio_sysfs_irq, irq_flags,
199 "gpiolib", value_sd);
200 if (ret < 0)
201 goto free_id;
202
Alexandre Courbote3a2e872014-10-23 17:27:07 +0900203 ret = gpiochip_lock_as_irq(desc->chip, gpio_chip_hwgpio(desc));
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900204 if (ret < 0) {
205 gpiod_warn(desc, "failed to flag the GPIO for IRQ\n");
206 goto free_id;
207 }
208
209 desc->flags |= gpio_flags;
210 return 0;
211
212free_id:
213 idr_remove(&dirent_idr, id);
214 desc->flags &= GPIO_FLAGS_MASK;
215free_sd:
216 if (value_sd)
217 sysfs_put(value_sd);
218err_out:
219 return ret;
220}
221
222static const struct {
223 const char *name;
224 unsigned long flags;
225} trigger_types[] = {
226 { "none", 0 },
227 { "falling", BIT(FLAG_TRIG_FALL) },
228 { "rising", BIT(FLAG_TRIG_RISE) },
229 { "both", BIT(FLAG_TRIG_FALL) | BIT(FLAG_TRIG_RISE) },
230};
231
232static ssize_t gpio_edge_show(struct device *dev,
233 struct device_attribute *attr, char *buf)
234{
235 const struct gpio_desc *desc = dev_get_drvdata(dev);
236 ssize_t status;
237
238 mutex_lock(&sysfs_lock);
239
240 if (!test_bit(FLAG_EXPORT, &desc->flags))
241 status = -EIO;
242 else {
243 int i;
244
245 status = 0;
246 for (i = 0; i < ARRAY_SIZE(trigger_types); i++)
247 if ((desc->flags & GPIO_TRIGGER_MASK)
248 == trigger_types[i].flags) {
249 status = sprintf(buf, "%s\n",
250 trigger_types[i].name);
251 break;
252 }
253 }
254
255 mutex_unlock(&sysfs_lock);
256 return status;
257}
258
259static ssize_t gpio_edge_store(struct device *dev,
260 struct device_attribute *attr, const char *buf, size_t size)
261{
262 struct gpio_desc *desc = dev_get_drvdata(dev);
263 ssize_t status;
264 int i;
265
266 for (i = 0; i < ARRAY_SIZE(trigger_types); i++)
267 if (sysfs_streq(trigger_types[i].name, buf))
268 goto found;
269 return -EINVAL;
270
271found:
272 mutex_lock(&sysfs_lock);
273
274 if (!test_bit(FLAG_EXPORT, &desc->flags))
275 status = -EIO;
276 else {
277 status = gpio_setup_irq(desc, dev, trigger_types[i].flags);
278 if (!status)
279 status = size;
280 }
281
282 mutex_unlock(&sysfs_lock);
283
284 return status;
285}
286
287static DEVICE_ATTR(edge, 0644, gpio_edge_show, gpio_edge_store);
288
289static int sysfs_set_active_low(struct gpio_desc *desc, struct device *dev,
290 int value)
291{
292 int status = 0;
293
294 if (!!test_bit(FLAG_ACTIVE_LOW, &desc->flags) == !!value)
295 return 0;
296
297 if (value)
298 set_bit(FLAG_ACTIVE_LOW, &desc->flags);
299 else
300 clear_bit(FLAG_ACTIVE_LOW, &desc->flags);
301
302 /* reconfigure poll(2) support if enabled on one edge only */
303 if (dev != NULL && (!!test_bit(FLAG_TRIG_RISE, &desc->flags) ^
304 !!test_bit(FLAG_TRIG_FALL, &desc->flags))) {
305 unsigned long trigger_flags = desc->flags & GPIO_TRIGGER_MASK;
306
307 gpio_setup_irq(desc, dev, 0);
308 status = gpio_setup_irq(desc, dev, trigger_flags);
309 }
310
311 return status;
312}
313
314static ssize_t gpio_active_low_show(struct device *dev,
315 struct device_attribute *attr, char *buf)
316{
317 const struct gpio_desc *desc = dev_get_drvdata(dev);
318 ssize_t status;
319
320 mutex_lock(&sysfs_lock);
321
322 if (!test_bit(FLAG_EXPORT, &desc->flags))
323 status = -EIO;
324 else
325 status = sprintf(buf, "%d\n",
326 !!test_bit(FLAG_ACTIVE_LOW, &desc->flags));
327
328 mutex_unlock(&sysfs_lock);
329
330 return status;
331}
332
333static ssize_t gpio_active_low_store(struct device *dev,
334 struct device_attribute *attr, const char *buf, size_t size)
335{
336 struct gpio_desc *desc = dev_get_drvdata(dev);
337 ssize_t status;
338
339 mutex_lock(&sysfs_lock);
340
341 if (!test_bit(FLAG_EXPORT, &desc->flags)) {
342 status = -EIO;
343 } else {
344 long value;
345
346 status = kstrtol(buf, 0, &value);
347 if (status == 0)
348 status = sysfs_set_active_low(desc, dev, value != 0);
349 }
350
351 mutex_unlock(&sysfs_lock);
352
353 return status ? : size;
354}
355
Johan Hovold0915e6f2015-01-13 13:00:05 +0100356static DEVICE_ATTR(active_low, 0644,
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900357 gpio_active_low_show, gpio_active_low_store);
358
Johan Hovold0915e6f2015-01-13 13:00:05 +0100359static struct attribute *gpio_attrs[] = {
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900360 &dev_attr_value.attr,
361 &dev_attr_active_low.attr,
362 NULL,
363};
Johan Hovold0915e6f2015-01-13 13:00:05 +0100364ATTRIBUTE_GROUPS(gpio);
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900365
366/*
367 * /sys/class/gpio/gpiochipN/
368 * /base ... matching gpio_chip.base (N)
369 * /label ... matching gpio_chip.label
370 * /ngpio ... matching gpio_chip.ngpio
371 */
372
373static ssize_t chip_base_show(struct device *dev,
374 struct device_attribute *attr, char *buf)
375{
376 const struct gpio_chip *chip = dev_get_drvdata(dev);
377
378 return sprintf(buf, "%d\n", chip->base);
379}
380static DEVICE_ATTR(base, 0444, chip_base_show, NULL);
381
382static ssize_t chip_label_show(struct device *dev,
383 struct device_attribute *attr, char *buf)
384{
385 const struct gpio_chip *chip = dev_get_drvdata(dev);
386
387 return sprintf(buf, "%s\n", chip->label ? : "");
388}
389static DEVICE_ATTR(label, 0444, chip_label_show, NULL);
390
391static ssize_t chip_ngpio_show(struct device *dev,
392 struct device_attribute *attr, char *buf)
393{
394 const struct gpio_chip *chip = dev_get_drvdata(dev);
395
396 return sprintf(buf, "%u\n", chip->ngpio);
397}
398static DEVICE_ATTR(ngpio, 0444, chip_ngpio_show, NULL);
399
Johan Hovold121b6a72015-01-13 13:00:04 +0100400static struct attribute *gpiochip_attrs[] = {
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900401 &dev_attr_base.attr,
402 &dev_attr_label.attr,
403 &dev_attr_ngpio.attr,
404 NULL,
405};
Johan Hovold121b6a72015-01-13 13:00:04 +0100406ATTRIBUTE_GROUPS(gpiochip);
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900407
408/*
409 * /sys/class/gpio/export ... write-only
410 * integer N ... number of GPIO to export (full access)
411 * /sys/class/gpio/unexport ... write-only
412 * integer N ... number of GPIO to unexport
413 */
414static ssize_t export_store(struct class *class,
415 struct class_attribute *attr,
416 const char *buf, size_t len)
417{
418 long gpio;
419 struct gpio_desc *desc;
420 int status;
421
422 status = kstrtol(buf, 0, &gpio);
423 if (status < 0)
424 goto done;
425
426 desc = gpio_to_desc(gpio);
427 /* reject invalid GPIOs */
428 if (!desc) {
429 pr_warn("%s: invalid GPIO %ld\n", __func__, gpio);
430 return -EINVAL;
431 }
432
433 /* No extra locking here; FLAG_SYSFS just signifies that the
434 * request and export were done by on behalf of userspace, so
435 * they may be undone on its behalf too.
436 */
437
438 status = gpiod_request(desc, "sysfs");
439 if (status < 0) {
440 if (status == -EPROBE_DEFER)
441 status = -ENODEV;
442 goto done;
443 }
444 status = gpiod_export(desc, true);
445 if (status < 0)
446 gpiod_free(desc);
447 else
448 set_bit(FLAG_SYSFS, &desc->flags);
449
450done:
451 if (status)
452 pr_debug("%s: status %d\n", __func__, status);
453 return status ? : len;
454}
455
456static ssize_t unexport_store(struct class *class,
457 struct class_attribute *attr,
458 const char *buf, size_t len)
459{
460 long gpio;
461 struct gpio_desc *desc;
462 int status;
463
464 status = kstrtol(buf, 0, &gpio);
465 if (status < 0)
466 goto done;
467
468 desc = gpio_to_desc(gpio);
469 /* reject bogus commands (gpio_unexport ignores them) */
470 if (!desc) {
471 pr_warn("%s: invalid GPIO %ld\n", __func__, gpio);
472 return -EINVAL;
473 }
474
475 status = -EINVAL;
476
477 /* No extra locking here; FLAG_SYSFS just signifies that the
478 * request and export were done by on behalf of userspace, so
479 * they may be undone on its behalf too.
480 */
481 if (test_and_clear_bit(FLAG_SYSFS, &desc->flags)) {
482 status = 0;
483 gpiod_free(desc);
484 }
485done:
486 if (status)
487 pr_debug("%s: status %d\n", __func__, status);
488 return status ? : len;
489}
490
491static struct class_attribute gpio_class_attrs[] = {
492 __ATTR(export, 0200, NULL, export_store),
493 __ATTR(unexport, 0200, NULL, unexport_store),
494 __ATTR_NULL,
495};
496
497static struct class gpio_class = {
498 .name = "gpio",
499 .owner = THIS_MODULE,
500
501 .class_attrs = gpio_class_attrs,
502};
503
504
505/**
506 * gpiod_export - export a GPIO through sysfs
507 * @gpio: gpio to make available, already requested
508 * @direction_may_change: true if userspace may change gpio direction
509 * Context: arch_initcall or later
510 *
511 * When drivers want to make a GPIO accessible to userspace after they
512 * have requested it -- perhaps while debugging, or as part of their
513 * public interface -- they may use this routine. If the GPIO can
514 * change direction (some can't) and the caller allows it, userspace
515 * will see "direction" sysfs attribute which may be used to change
516 * the gpio's direction. A "value" attribute will always be provided.
517 *
518 * Returns zero on success, else an error.
519 */
520int gpiod_export(struct gpio_desc *desc, bool direction_may_change)
521{
522 unsigned long flags;
523 int status;
524 const char *ioname = NULL;
525 struct device *dev;
526 int offset;
527
528 /* can't export until sysfs is available ... */
529 if (!gpio_class.p) {
530 pr_debug("%s: called too early!\n", __func__);
531 return -ENOENT;
532 }
533
534 if (!desc) {
535 pr_debug("%s: invalid gpio descriptor\n", __func__);
536 return -EINVAL;
537 }
538
539 mutex_lock(&sysfs_lock);
540
541 spin_lock_irqsave(&gpio_lock, flags);
542 if (!test_bit(FLAG_REQUESTED, &desc->flags) ||
543 test_bit(FLAG_EXPORT, &desc->flags)) {
544 spin_unlock_irqrestore(&gpio_lock, flags);
545 gpiod_dbg(desc, "%s: unavailable (requested=%d, exported=%d)\n",
546 __func__,
547 test_bit(FLAG_REQUESTED, &desc->flags),
548 test_bit(FLAG_EXPORT, &desc->flags));
549 status = -EPERM;
550 goto fail_unlock;
551 }
552
553 if (!desc->chip->direction_input || !desc->chip->direction_output)
554 direction_may_change = false;
555 spin_unlock_irqrestore(&gpio_lock, flags);
556
557 offset = gpio_chip_hwgpio(desc);
558 if (desc->chip->names && desc->chip->names[offset])
559 ioname = desc->chip->names[offset];
560
Johan Hovold0915e6f2015-01-13 13:00:05 +0100561 dev = device_create_with_groups(&gpio_class, desc->chip->dev,
562 MKDEV(0, 0), desc, gpio_groups,
563 ioname ? ioname : "gpio%u",
564 desc_to_gpio(desc));
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900565 if (IS_ERR(dev)) {
566 status = PTR_ERR(dev);
567 goto fail_unlock;
568 }
569
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900570 if (direction_may_change) {
571 status = device_create_file(dev, &dev_attr_direction);
572 if (status)
573 goto fail_unregister_device;
574 }
575
576 if (gpiod_to_irq(desc) >= 0 && (direction_may_change ||
577 !test_bit(FLAG_IS_OUT, &desc->flags))) {
578 status = device_create_file(dev, &dev_attr_edge);
579 if (status)
Johan Hovold0915e6f2015-01-13 13:00:05 +0100580 goto fail_remove_attr_direction;
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900581 }
582
583 set_bit(FLAG_EXPORT, &desc->flags);
584 mutex_unlock(&sysfs_lock);
585 return 0;
586
Johan Hovold0915e6f2015-01-13 13:00:05 +0100587fail_remove_attr_direction:
588 device_remove_file(dev, &dev_attr_direction);
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900589fail_unregister_device:
590 device_unregister(dev);
591fail_unlock:
592 mutex_unlock(&sysfs_lock);
593 gpiod_dbg(desc, "%s: status %d\n", __func__, status);
594 return status;
595}
596EXPORT_SYMBOL_GPL(gpiod_export);
597
598static int match_export(struct device *dev, const void *data)
599{
600 return dev_get_drvdata(dev) == data;
601}
602
603/**
604 * gpiod_export_link - create a sysfs link to an exported GPIO node
605 * @dev: device under which to create symlink
606 * @name: name of the symlink
607 * @gpio: gpio to create symlink to, already exported
608 *
609 * Set up a symlink from /sys/.../dev/name to /sys/class/gpio/gpioN
610 * node. Caller is responsible for unlinking.
611 *
612 * Returns zero on success, else an error.
613 */
614int gpiod_export_link(struct device *dev, const char *name,
615 struct gpio_desc *desc)
616{
617 int status = -EINVAL;
618
619 if (!desc) {
620 pr_warn("%s: invalid GPIO\n", __func__);
621 return -EINVAL;
622 }
623
624 mutex_lock(&sysfs_lock);
625
626 if (test_bit(FLAG_EXPORT, &desc->flags)) {
627 struct device *tdev;
628
629 tdev = class_find_device(&gpio_class, NULL, desc, match_export);
630 if (tdev != NULL) {
631 status = sysfs_create_link(&dev->kobj, &tdev->kobj,
632 name);
633 } else {
634 status = -ENODEV;
635 }
636 }
637
638 mutex_unlock(&sysfs_lock);
639
640 if (status)
641 gpiod_dbg(desc, "%s: status %d\n", __func__, status);
642
643 return status;
644}
645EXPORT_SYMBOL_GPL(gpiod_export_link);
646
647/**
648 * gpiod_sysfs_set_active_low - set the polarity of gpio sysfs value
649 * @gpio: gpio to change
650 * @value: non-zero to use active low, i.e. inverted values
651 *
652 * Set the polarity of /sys/class/gpio/gpioN/value sysfs attribute.
653 * The GPIO does not have to be exported yet. If poll(2) support has
654 * been enabled for either rising or falling edge, it will be
655 * reconfigured to follow the new polarity.
656 *
657 * Returns zero on success, else an error.
658 */
659int gpiod_sysfs_set_active_low(struct gpio_desc *desc, int value)
660{
661 struct device *dev = NULL;
662 int status = -EINVAL;
663
664 if (!desc) {
665 pr_warn("%s: invalid GPIO\n", __func__);
666 return -EINVAL;
667 }
668
669 mutex_lock(&sysfs_lock);
670
671 if (test_bit(FLAG_EXPORT, &desc->flags)) {
672 dev = class_find_device(&gpio_class, NULL, desc, match_export);
673 if (dev == NULL) {
674 status = -ENODEV;
675 goto unlock;
676 }
677 }
678
679 status = sysfs_set_active_low(desc, dev, value);
680
681unlock:
682 mutex_unlock(&sysfs_lock);
683
684 if (status)
685 gpiod_dbg(desc, "%s: status %d\n", __func__, status);
686
687 return status;
688}
689EXPORT_SYMBOL_GPL(gpiod_sysfs_set_active_low);
690
691/**
692 * gpiod_unexport - reverse effect of gpio_export()
693 * @gpio: gpio to make unavailable
694 *
695 * This is implicit on gpio_free().
696 */
697void gpiod_unexport(struct gpio_desc *desc)
698{
699 int status = 0;
700 struct device *dev = NULL;
701
702 if (!desc) {
703 pr_warn("%s: invalid GPIO\n", __func__);
704 return;
705 }
706
707 mutex_lock(&sysfs_lock);
708
709 if (test_bit(FLAG_EXPORT, &desc->flags)) {
710
711 dev = class_find_device(&gpio_class, NULL, desc, match_export);
712 if (dev) {
713 gpio_setup_irq(desc, dev, 0);
714 clear_bit(FLAG_EXPORT, &desc->flags);
715 } else
716 status = -ENODEV;
717 }
718
719 mutex_unlock(&sysfs_lock);
720
721 if (dev) {
Johan Hovold0915e6f2015-01-13 13:00:05 +0100722 device_remove_file(dev, &dev_attr_edge);
723 device_remove_file(dev, &dev_attr_direction);
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900724 device_unregister(dev);
725 put_device(dev);
726 }
727
728 if (status)
729 gpiod_dbg(desc, "%s: status %d\n", __func__, status);
730}
731EXPORT_SYMBOL_GPL(gpiod_unexport);
732
733int gpiochip_export(struct gpio_chip *chip)
734{
735 int status;
736 struct device *dev;
737
738 /* Many systems register gpio chips for SOC support very early,
739 * before driver model support is available. In those cases we
740 * export this later, in gpiolib_sysfs_init() ... here we just
741 * verify that _some_ field of gpio_class got initialized.
742 */
743 if (!gpio_class.p)
744 return 0;
745
746 /* use chip->base for the ID; it's already known to be unique */
747 mutex_lock(&sysfs_lock);
Johan Hovold121b6a72015-01-13 13:00:04 +0100748 dev = device_create_with_groups(&gpio_class, chip->dev, MKDEV(0, 0),
749 chip, gpiochip_groups,
750 "gpiochip%d", chip->base);
751 if (IS_ERR(dev))
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900752 status = PTR_ERR(dev);
Johan Hovold121b6a72015-01-13 13:00:04 +0100753 else
754 status = 0;
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900755 chip->exported = (status == 0);
756 mutex_unlock(&sysfs_lock);
757
Alexandre Courbot14141a92014-07-22 16:17:40 +0900758 if (status)
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900759 chip_dbg(chip, "%s: status %d\n", __func__, status);
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900760
761 return status;
762}
763
764void gpiochip_unexport(struct gpio_chip *chip)
765{
766 int status;
767 struct device *dev;
768
769 mutex_lock(&sysfs_lock);
770 dev = class_find_device(&gpio_class, NULL, chip, match_export);
771 if (dev) {
772 put_device(dev);
773 device_unregister(dev);
774 chip->exported = false;
775 status = 0;
776 } else
777 status = -ENODEV;
778 mutex_unlock(&sysfs_lock);
779
780 if (status)
781 chip_dbg(chip, "%s: status %d\n", __func__, status);
782}
783
784static int __init gpiolib_sysfs_init(void)
785{
786 int status;
787 unsigned long flags;
788 struct gpio_chip *chip;
789
790 status = class_register(&gpio_class);
791 if (status < 0)
792 return status;
793
794 /* Scan and register the gpio_chips which registered very
795 * early (e.g. before the class_register above was called).
796 *
797 * We run before arch_initcall() so chip->dev nodes can have
798 * registered, and so arch_initcall() can always gpio_export().
799 */
800 spin_lock_irqsave(&gpio_lock, flags);
801 list_for_each_entry(chip, &gpio_chips, list) {
Alexandre Courbot7fd834a2014-07-23 23:56:53 +0900802 if (chip->exported)
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900803 continue;
804
Alexandre Courbot14141a92014-07-22 16:17:40 +0900805 /*
806 * TODO we yield gpio_lock here because gpiochip_export()
807 * acquires a mutex. This is unsafe and needs to be fixed.
808 *
809 * Also it would be nice to use gpiochip_find() here so we
810 * can keep gpio_chips local to gpiolib.c, but the yield of
811 * gpio_lock prevents us from doing this.
812 */
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900813 spin_unlock_irqrestore(&gpio_lock, flags);
814 status = gpiochip_export(chip);
815 spin_lock_irqsave(&gpio_lock, flags);
816 }
817 spin_unlock_irqrestore(&gpio_lock, flags);
818
819
820 return status;
821}
822postcore_initcall(gpiolib_sysfs_init);