Commit | Line | Data |
---|---|---|
0eb4c6c2 AC |
1 | #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 | ||
12 | static DEFINE_IDR(dirent_idr); | |
13 | ||
14 | ||
15 | /* lock protects against unexport_gpio() being called while | |
16 | * sysfs files are active. | |
17 | */ | |
18 | static 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 | ||
41 | static ssize_t gpio_direction_show(struct device *dev, | |
42 | struct device_attribute *attr, char *buf) | |
43 | { | |
44 | const struct gpio_desc *desc = dev_get_drvdata(dev); | |
45 | 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 | ||
62 | static 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 | ||
85 | static /* const */ DEVICE_ATTR(direction, 0644, | |
86 | gpio_direction_show, gpio_direction_store); | |
87 | ||
88 | static 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 | ||
105 | static 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 | ||
131 | static const DEVICE_ATTR(value, 0644, | |
132 | gpio_value_show, gpio_value_store); | |
133 | ||
134 | static 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 | ||
142 | static 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) { | |
d74be6df | 164 | gpio_unlock_as_irq(desc->chip, gpio_chip_hwgpio(desc)); |
0eb4c6c2 AC |
165 | 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 | ||
d74be6df | 203 | ret = gpio_lock_as_irq(desc->chip, gpio_chip_hwgpio(desc)); |
0eb4c6c2 AC |
204 | 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 | ||
212 | free_id: | |
213 | idr_remove(&dirent_idr, id); | |
214 | desc->flags &= GPIO_FLAGS_MASK; | |
215 | free_sd: | |
216 | if (value_sd) | |
217 | sysfs_put(value_sd); | |
218 | err_out: | |
219 | return ret; | |
220 | } | |
221 | ||
222 | static 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 | ||
232 | static 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 | ||
259 | static 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 | ||
271 | found: | |
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 | ||
287 | static DEVICE_ATTR(edge, 0644, gpio_edge_show, gpio_edge_store); | |
288 | ||
289 | static 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 | ||
314 | static 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 | ||
333 | static 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 | ||
356 | static const DEVICE_ATTR(active_low, 0644, | |
357 | gpio_active_low_show, gpio_active_low_store); | |
358 | ||
359 | static const struct attribute *gpio_attrs[] = { | |
360 | &dev_attr_value.attr, | |
361 | &dev_attr_active_low.attr, | |
362 | NULL, | |
363 | }; | |
364 | ||
365 | static const struct attribute_group gpio_attr_group = { | |
366 | .attrs = (struct attribute **) gpio_attrs, | |
367 | }; | |
368 | ||
369 | /* | |
370 | * /sys/class/gpio/gpiochipN/ | |
371 | * /base ... matching gpio_chip.base (N) | |
372 | * /label ... matching gpio_chip.label | |
373 | * /ngpio ... matching gpio_chip.ngpio | |
374 | */ | |
375 | ||
376 | static ssize_t chip_base_show(struct device *dev, | |
377 | struct device_attribute *attr, char *buf) | |
378 | { | |
379 | const struct gpio_chip *chip = dev_get_drvdata(dev); | |
380 | ||
381 | return sprintf(buf, "%d\n", chip->base); | |
382 | } | |
383 | static DEVICE_ATTR(base, 0444, chip_base_show, NULL); | |
384 | ||
385 | static ssize_t chip_label_show(struct device *dev, | |
386 | struct device_attribute *attr, char *buf) | |
387 | { | |
388 | const struct gpio_chip *chip = dev_get_drvdata(dev); | |
389 | ||
390 | return sprintf(buf, "%s\n", chip->label ? : ""); | |
391 | } | |
392 | static DEVICE_ATTR(label, 0444, chip_label_show, NULL); | |
393 | ||
394 | static ssize_t chip_ngpio_show(struct device *dev, | |
395 | struct device_attribute *attr, char *buf) | |
396 | { | |
397 | const struct gpio_chip *chip = dev_get_drvdata(dev); | |
398 | ||
399 | return sprintf(buf, "%u\n", chip->ngpio); | |
400 | } | |
401 | static DEVICE_ATTR(ngpio, 0444, chip_ngpio_show, NULL); | |
402 | ||
403 | static const struct attribute *gpiochip_attrs[] = { | |
404 | &dev_attr_base.attr, | |
405 | &dev_attr_label.attr, | |
406 | &dev_attr_ngpio.attr, | |
407 | NULL, | |
408 | }; | |
409 | ||
410 | static const struct attribute_group gpiochip_attr_group = { | |
411 | .attrs = (struct attribute **) gpiochip_attrs, | |
412 | }; | |
413 | ||
414 | /* | |
415 | * /sys/class/gpio/export ... write-only | |
416 | * integer N ... number of GPIO to export (full access) | |
417 | * /sys/class/gpio/unexport ... write-only | |
418 | * integer N ... number of GPIO to unexport | |
419 | */ | |
420 | static ssize_t export_store(struct class *class, | |
421 | struct class_attribute *attr, | |
422 | const char *buf, size_t len) | |
423 | { | |
424 | long gpio; | |
425 | struct gpio_desc *desc; | |
426 | int status; | |
427 | ||
428 | status = kstrtol(buf, 0, &gpio); | |
429 | if (status < 0) | |
430 | goto done; | |
431 | ||
432 | desc = gpio_to_desc(gpio); | |
433 | /* reject invalid GPIOs */ | |
434 | if (!desc) { | |
435 | pr_warn("%s: invalid GPIO %ld\n", __func__, gpio); | |
436 | return -EINVAL; | |
437 | } | |
438 | ||
439 | /* No extra locking here; FLAG_SYSFS just signifies that the | |
440 | * request and export were done by on behalf of userspace, so | |
441 | * they may be undone on its behalf too. | |
442 | */ | |
443 | ||
444 | status = gpiod_request(desc, "sysfs"); | |
445 | if (status < 0) { | |
446 | if (status == -EPROBE_DEFER) | |
447 | status = -ENODEV; | |
448 | goto done; | |
449 | } | |
450 | status = gpiod_export(desc, true); | |
451 | if (status < 0) | |
452 | gpiod_free(desc); | |
453 | else | |
454 | set_bit(FLAG_SYSFS, &desc->flags); | |
455 | ||
456 | done: | |
457 | if (status) | |
458 | pr_debug("%s: status %d\n", __func__, status); | |
459 | return status ? : len; | |
460 | } | |
461 | ||
462 | static ssize_t unexport_store(struct class *class, | |
463 | struct class_attribute *attr, | |
464 | const char *buf, size_t len) | |
465 | { | |
466 | long gpio; | |
467 | struct gpio_desc *desc; | |
468 | int status; | |
469 | ||
470 | status = kstrtol(buf, 0, &gpio); | |
471 | if (status < 0) | |
472 | goto done; | |
473 | ||
474 | desc = gpio_to_desc(gpio); | |
475 | /* reject bogus commands (gpio_unexport ignores them) */ | |
476 | if (!desc) { | |
477 | pr_warn("%s: invalid GPIO %ld\n", __func__, gpio); | |
478 | return -EINVAL; | |
479 | } | |
480 | ||
481 | status = -EINVAL; | |
482 | ||
483 | /* No extra locking here; FLAG_SYSFS just signifies that the | |
484 | * request and export were done by on behalf of userspace, so | |
485 | * they may be undone on its behalf too. | |
486 | */ | |
487 | if (test_and_clear_bit(FLAG_SYSFS, &desc->flags)) { | |
488 | status = 0; | |
489 | gpiod_free(desc); | |
490 | } | |
491 | done: | |
492 | if (status) | |
493 | pr_debug("%s: status %d\n", __func__, status); | |
494 | return status ? : len; | |
495 | } | |
496 | ||
497 | static struct class_attribute gpio_class_attrs[] = { | |
498 | __ATTR(export, 0200, NULL, export_store), | |
499 | __ATTR(unexport, 0200, NULL, unexport_store), | |
500 | __ATTR_NULL, | |
501 | }; | |
502 | ||
503 | static struct class gpio_class = { | |
504 | .name = "gpio", | |
505 | .owner = THIS_MODULE, | |
506 | ||
507 | .class_attrs = gpio_class_attrs, | |
508 | }; | |
509 | ||
510 | ||
511 | /** | |
512 | * gpiod_export - export a GPIO through sysfs | |
513 | * @gpio: gpio to make available, already requested | |
514 | * @direction_may_change: true if userspace may change gpio direction | |
515 | * Context: arch_initcall or later | |
516 | * | |
517 | * When drivers want to make a GPIO accessible to userspace after they | |
518 | * have requested it -- perhaps while debugging, or as part of their | |
519 | * public interface -- they may use this routine. If the GPIO can | |
520 | * change direction (some can't) and the caller allows it, userspace | |
521 | * will see "direction" sysfs attribute which may be used to change | |
522 | * the gpio's direction. A "value" attribute will always be provided. | |
523 | * | |
524 | * Returns zero on success, else an error. | |
525 | */ | |
526 | int gpiod_export(struct gpio_desc *desc, bool direction_may_change) | |
527 | { | |
528 | unsigned long flags; | |
529 | int status; | |
530 | const char *ioname = NULL; | |
531 | struct device *dev; | |
532 | int offset; | |
533 | ||
534 | /* can't export until sysfs is available ... */ | |
535 | if (!gpio_class.p) { | |
536 | pr_debug("%s: called too early!\n", __func__); | |
537 | return -ENOENT; | |
538 | } | |
539 | ||
540 | if (!desc) { | |
541 | pr_debug("%s: invalid gpio descriptor\n", __func__); | |
542 | return -EINVAL; | |
543 | } | |
544 | ||
545 | mutex_lock(&sysfs_lock); | |
546 | ||
547 | spin_lock_irqsave(&gpio_lock, flags); | |
548 | if (!test_bit(FLAG_REQUESTED, &desc->flags) || | |
549 | test_bit(FLAG_EXPORT, &desc->flags)) { | |
550 | spin_unlock_irqrestore(&gpio_lock, flags); | |
551 | gpiod_dbg(desc, "%s: unavailable (requested=%d, exported=%d)\n", | |
552 | __func__, | |
553 | test_bit(FLAG_REQUESTED, &desc->flags), | |
554 | test_bit(FLAG_EXPORT, &desc->flags)); | |
555 | status = -EPERM; | |
556 | goto fail_unlock; | |
557 | } | |
558 | ||
559 | if (!desc->chip->direction_input || !desc->chip->direction_output) | |
560 | direction_may_change = false; | |
561 | spin_unlock_irqrestore(&gpio_lock, flags); | |
562 | ||
563 | offset = gpio_chip_hwgpio(desc); | |
564 | if (desc->chip->names && desc->chip->names[offset]) | |
565 | ioname = desc->chip->names[offset]; | |
566 | ||
567 | dev = device_create(&gpio_class, desc->chip->dev, MKDEV(0, 0), | |
568 | desc, ioname ? ioname : "gpio%u", | |
569 | desc_to_gpio(desc)); | |
570 | if (IS_ERR(dev)) { | |
571 | status = PTR_ERR(dev); | |
572 | goto fail_unlock; | |
573 | } | |
574 | ||
575 | status = sysfs_create_group(&dev->kobj, &gpio_attr_group); | |
576 | if (status) | |
577 | goto fail_unregister_device; | |
578 | ||
579 | if (direction_may_change) { | |
580 | status = device_create_file(dev, &dev_attr_direction); | |
581 | if (status) | |
582 | goto fail_unregister_device; | |
583 | } | |
584 | ||
585 | if (gpiod_to_irq(desc) >= 0 && (direction_may_change || | |
586 | !test_bit(FLAG_IS_OUT, &desc->flags))) { | |
587 | status = device_create_file(dev, &dev_attr_edge); | |
588 | if (status) | |
589 | goto fail_unregister_device; | |
590 | } | |
591 | ||
592 | set_bit(FLAG_EXPORT, &desc->flags); | |
593 | mutex_unlock(&sysfs_lock); | |
594 | return 0; | |
595 | ||
596 | fail_unregister_device: | |
597 | device_unregister(dev); | |
598 | fail_unlock: | |
599 | mutex_unlock(&sysfs_lock); | |
600 | gpiod_dbg(desc, "%s: status %d\n", __func__, status); | |
601 | return status; | |
602 | } | |
603 | EXPORT_SYMBOL_GPL(gpiod_export); | |
604 | ||
605 | static int match_export(struct device *dev, const void *data) | |
606 | { | |
607 | return dev_get_drvdata(dev) == data; | |
608 | } | |
609 | ||
610 | /** | |
611 | * gpiod_export_link - create a sysfs link to an exported GPIO node | |
612 | * @dev: device under which to create symlink | |
613 | * @name: name of the symlink | |
614 | * @gpio: gpio to create symlink to, already exported | |
615 | * | |
616 | * Set up a symlink from /sys/.../dev/name to /sys/class/gpio/gpioN | |
617 | * node. Caller is responsible for unlinking. | |
618 | * | |
619 | * Returns zero on success, else an error. | |
620 | */ | |
621 | int gpiod_export_link(struct device *dev, const char *name, | |
622 | struct gpio_desc *desc) | |
623 | { | |
624 | int status = -EINVAL; | |
625 | ||
626 | if (!desc) { | |
627 | pr_warn("%s: invalid GPIO\n", __func__); | |
628 | return -EINVAL; | |
629 | } | |
630 | ||
631 | mutex_lock(&sysfs_lock); | |
632 | ||
633 | if (test_bit(FLAG_EXPORT, &desc->flags)) { | |
634 | struct device *tdev; | |
635 | ||
636 | tdev = class_find_device(&gpio_class, NULL, desc, match_export); | |
637 | if (tdev != NULL) { | |
638 | status = sysfs_create_link(&dev->kobj, &tdev->kobj, | |
639 | name); | |
640 | } else { | |
641 | status = -ENODEV; | |
642 | } | |
643 | } | |
644 | ||
645 | mutex_unlock(&sysfs_lock); | |
646 | ||
647 | if (status) | |
648 | gpiod_dbg(desc, "%s: status %d\n", __func__, status); | |
649 | ||
650 | return status; | |
651 | } | |
652 | EXPORT_SYMBOL_GPL(gpiod_export_link); | |
653 | ||
654 | /** | |
655 | * gpiod_sysfs_set_active_low - set the polarity of gpio sysfs value | |
656 | * @gpio: gpio to change | |
657 | * @value: non-zero to use active low, i.e. inverted values | |
658 | * | |
659 | * Set the polarity of /sys/class/gpio/gpioN/value sysfs attribute. | |
660 | * The GPIO does not have to be exported yet. If poll(2) support has | |
661 | * been enabled for either rising or falling edge, it will be | |
662 | * reconfigured to follow the new polarity. | |
663 | * | |
664 | * Returns zero on success, else an error. | |
665 | */ | |
666 | int gpiod_sysfs_set_active_low(struct gpio_desc *desc, int value) | |
667 | { | |
668 | struct device *dev = NULL; | |
669 | int status = -EINVAL; | |
670 | ||
671 | if (!desc) { | |
672 | pr_warn("%s: invalid GPIO\n", __func__); | |
673 | return -EINVAL; | |
674 | } | |
675 | ||
676 | mutex_lock(&sysfs_lock); | |
677 | ||
678 | if (test_bit(FLAG_EXPORT, &desc->flags)) { | |
679 | dev = class_find_device(&gpio_class, NULL, desc, match_export); | |
680 | if (dev == NULL) { | |
681 | status = -ENODEV; | |
682 | goto unlock; | |
683 | } | |
684 | } | |
685 | ||
686 | status = sysfs_set_active_low(desc, dev, value); | |
687 | ||
688 | unlock: | |
689 | mutex_unlock(&sysfs_lock); | |
690 | ||
691 | if (status) | |
692 | gpiod_dbg(desc, "%s: status %d\n", __func__, status); | |
693 | ||
694 | return status; | |
695 | } | |
696 | EXPORT_SYMBOL_GPL(gpiod_sysfs_set_active_low); | |
697 | ||
698 | /** | |
699 | * gpiod_unexport - reverse effect of gpio_export() | |
700 | * @gpio: gpio to make unavailable | |
701 | * | |
702 | * This is implicit on gpio_free(). | |
703 | */ | |
704 | void gpiod_unexport(struct gpio_desc *desc) | |
705 | { | |
706 | int status = 0; | |
707 | struct device *dev = NULL; | |
708 | ||
709 | if (!desc) { | |
710 | pr_warn("%s: invalid GPIO\n", __func__); | |
711 | return; | |
712 | } | |
713 | ||
714 | mutex_lock(&sysfs_lock); | |
715 | ||
716 | if (test_bit(FLAG_EXPORT, &desc->flags)) { | |
717 | ||
718 | dev = class_find_device(&gpio_class, NULL, desc, match_export); | |
719 | if (dev) { | |
720 | gpio_setup_irq(desc, dev, 0); | |
721 | clear_bit(FLAG_EXPORT, &desc->flags); | |
722 | } else | |
723 | status = -ENODEV; | |
724 | } | |
725 | ||
726 | mutex_unlock(&sysfs_lock); | |
727 | ||
728 | if (dev) { | |
729 | device_unregister(dev); | |
730 | put_device(dev); | |
731 | } | |
732 | ||
733 | if (status) | |
734 | gpiod_dbg(desc, "%s: status %d\n", __func__, status); | |
735 | } | |
736 | EXPORT_SYMBOL_GPL(gpiod_unexport); | |
737 | ||
738 | int gpiochip_export(struct gpio_chip *chip) | |
739 | { | |
740 | int status; | |
741 | struct device *dev; | |
742 | ||
743 | /* Many systems register gpio chips for SOC support very early, | |
744 | * before driver model support is available. In those cases we | |
745 | * export this later, in gpiolib_sysfs_init() ... here we just | |
746 | * verify that _some_ field of gpio_class got initialized. | |
747 | */ | |
748 | if (!gpio_class.p) | |
749 | return 0; | |
750 | ||
751 | /* use chip->base for the ID; it's already known to be unique */ | |
752 | mutex_lock(&sysfs_lock); | |
753 | dev = device_create(&gpio_class, chip->dev, MKDEV(0, 0), chip, | |
754 | "gpiochip%d", chip->base); | |
755 | if (!IS_ERR(dev)) { | |
756 | status = sysfs_create_group(&dev->kobj, | |
757 | &gpiochip_attr_group); | |
758 | } else | |
759 | status = PTR_ERR(dev); | |
760 | chip->exported = (status == 0); | |
761 | mutex_unlock(&sysfs_lock); | |
762 | ||
14141a93 | 763 | if (status) |
0eb4c6c2 | 764 | chip_dbg(chip, "%s: status %d\n", __func__, status); |
0eb4c6c2 AC |
765 | |
766 | return status; | |
767 | } | |
768 | ||
769 | void gpiochip_unexport(struct gpio_chip *chip) | |
770 | { | |
771 | int status; | |
772 | struct device *dev; | |
773 | ||
774 | mutex_lock(&sysfs_lock); | |
775 | dev = class_find_device(&gpio_class, NULL, chip, match_export); | |
776 | if (dev) { | |
777 | put_device(dev); | |
778 | device_unregister(dev); | |
779 | chip->exported = false; | |
780 | status = 0; | |
781 | } else | |
782 | status = -ENODEV; | |
783 | mutex_unlock(&sysfs_lock); | |
784 | ||
785 | if (status) | |
786 | chip_dbg(chip, "%s: status %d\n", __func__, status); | |
787 | } | |
788 | ||
789 | static int __init gpiolib_sysfs_init(void) | |
790 | { | |
791 | int status; | |
792 | unsigned long flags; | |
793 | struct gpio_chip *chip; | |
794 | ||
795 | status = class_register(&gpio_class); | |
796 | if (status < 0) | |
797 | return status; | |
798 | ||
799 | /* Scan and register the gpio_chips which registered very | |
800 | * early (e.g. before the class_register above was called). | |
801 | * | |
802 | * We run before arch_initcall() so chip->dev nodes can have | |
803 | * registered, and so arch_initcall() can always gpio_export(). | |
804 | */ | |
805 | spin_lock_irqsave(&gpio_lock, flags); | |
806 | list_for_each_entry(chip, &gpio_chips, list) { | |
7fd834ad | 807 | if (chip->exported) |
0eb4c6c2 AC |
808 | continue; |
809 | ||
14141a93 AC |
810 | /* |
811 | * TODO we yield gpio_lock here because gpiochip_export() | |
812 | * acquires a mutex. This is unsafe and needs to be fixed. | |
813 | * | |
814 | * Also it would be nice to use gpiochip_find() here so we | |
815 | * can keep gpio_chips local to gpiolib.c, but the yield of | |
816 | * gpio_lock prevents us from doing this. | |
817 | */ | |
0eb4c6c2 AC |
818 | spin_unlock_irqrestore(&gpio_lock, flags); |
819 | status = gpiochip_export(chip); | |
820 | spin_lock_irqsave(&gpio_lock, flags); | |
821 | } | |
822 | spin_unlock_irqrestore(&gpio_lock, flags); | |
823 | ||
824 | ||
825 | return status; | |
826 | } | |
827 | postcore_initcall(gpiolib_sysfs_init); |