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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 | { | |
8e53b0f1 | 44 | struct gpio_desc *desc = dev_get_drvdata(dev); |
0eb4c6c2 AC |
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) { | |
e3a2e878 | 164 | gpiochip_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 | ||
e3a2e878 | 203 | ret = gpiochip_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 | ||
121b6a79 | 403 | static struct attribute *gpiochip_attrs[] = { |
0eb4c6c2 AC |
404 | &dev_attr_base.attr, |
405 | &dev_attr_label.attr, | |
406 | &dev_attr_ngpio.attr, | |
407 | NULL, | |
408 | }; | |
121b6a79 | 409 | ATTRIBUTE_GROUPS(gpiochip); |
0eb4c6c2 AC |
410 | |
411 | /* | |
412 | * /sys/class/gpio/export ... write-only | |
413 | * integer N ... number of GPIO to export (full access) | |
414 | * /sys/class/gpio/unexport ... write-only | |
415 | * integer N ... number of GPIO to unexport | |
416 | */ | |
417 | static ssize_t export_store(struct class *class, | |
418 | struct class_attribute *attr, | |
419 | const char *buf, size_t len) | |
420 | { | |
421 | long gpio; | |
422 | struct gpio_desc *desc; | |
423 | int status; | |
424 | ||
425 | status = kstrtol(buf, 0, &gpio); | |
426 | if (status < 0) | |
427 | goto done; | |
428 | ||
429 | desc = gpio_to_desc(gpio); | |
430 | /* reject invalid GPIOs */ | |
431 | if (!desc) { | |
432 | pr_warn("%s: invalid GPIO %ld\n", __func__, gpio); | |
433 | return -EINVAL; | |
434 | } | |
435 | ||
436 | /* No extra locking here; FLAG_SYSFS just signifies that the | |
437 | * request and export were done by on behalf of userspace, so | |
438 | * they may be undone on its behalf too. | |
439 | */ | |
440 | ||
441 | status = gpiod_request(desc, "sysfs"); | |
442 | if (status < 0) { | |
443 | if (status == -EPROBE_DEFER) | |
444 | status = -ENODEV; | |
445 | goto done; | |
446 | } | |
447 | status = gpiod_export(desc, true); | |
448 | if (status < 0) | |
449 | gpiod_free(desc); | |
450 | else | |
451 | set_bit(FLAG_SYSFS, &desc->flags); | |
452 | ||
453 | done: | |
454 | if (status) | |
455 | pr_debug("%s: status %d\n", __func__, status); | |
456 | return status ? : len; | |
457 | } | |
458 | ||
459 | static ssize_t unexport_store(struct class *class, | |
460 | struct class_attribute *attr, | |
461 | const char *buf, size_t len) | |
462 | { | |
463 | long gpio; | |
464 | struct gpio_desc *desc; | |
465 | int status; | |
466 | ||
467 | status = kstrtol(buf, 0, &gpio); | |
468 | if (status < 0) | |
469 | goto done; | |
470 | ||
471 | desc = gpio_to_desc(gpio); | |
472 | /* reject bogus commands (gpio_unexport ignores them) */ | |
473 | if (!desc) { | |
474 | pr_warn("%s: invalid GPIO %ld\n", __func__, gpio); | |
475 | return -EINVAL; | |
476 | } | |
477 | ||
478 | status = -EINVAL; | |
479 | ||
480 | /* No extra locking here; FLAG_SYSFS just signifies that the | |
481 | * request and export were done by on behalf of userspace, so | |
482 | * they may be undone on its behalf too. | |
483 | */ | |
484 | if (test_and_clear_bit(FLAG_SYSFS, &desc->flags)) { | |
485 | status = 0; | |
486 | gpiod_free(desc); | |
487 | } | |
488 | done: | |
489 | if (status) | |
490 | pr_debug("%s: status %d\n", __func__, status); | |
491 | return status ? : len; | |
492 | } | |
493 | ||
494 | static struct class_attribute gpio_class_attrs[] = { | |
495 | __ATTR(export, 0200, NULL, export_store), | |
496 | __ATTR(unexport, 0200, NULL, unexport_store), | |
497 | __ATTR_NULL, | |
498 | }; | |
499 | ||
500 | static struct class gpio_class = { | |
501 | .name = "gpio", | |
502 | .owner = THIS_MODULE, | |
503 | ||
504 | .class_attrs = gpio_class_attrs, | |
505 | }; | |
506 | ||
507 | ||
508 | /** | |
509 | * gpiod_export - export a GPIO through sysfs | |
510 | * @gpio: gpio to make available, already requested | |
511 | * @direction_may_change: true if userspace may change gpio direction | |
512 | * Context: arch_initcall or later | |
513 | * | |
514 | * When drivers want to make a GPIO accessible to userspace after they | |
515 | * have requested it -- perhaps while debugging, or as part of their | |
516 | * public interface -- they may use this routine. If the GPIO can | |
517 | * change direction (some can't) and the caller allows it, userspace | |
518 | * will see "direction" sysfs attribute which may be used to change | |
519 | * the gpio's direction. A "value" attribute will always be provided. | |
520 | * | |
521 | * Returns zero on success, else an error. | |
522 | */ | |
523 | int gpiod_export(struct gpio_desc *desc, bool direction_may_change) | |
524 | { | |
525 | unsigned long flags; | |
526 | int status; | |
527 | const char *ioname = NULL; | |
528 | struct device *dev; | |
529 | int offset; | |
530 | ||
531 | /* can't export until sysfs is available ... */ | |
532 | if (!gpio_class.p) { | |
533 | pr_debug("%s: called too early!\n", __func__); | |
534 | return -ENOENT; | |
535 | } | |
536 | ||
537 | if (!desc) { | |
538 | pr_debug("%s: invalid gpio descriptor\n", __func__); | |
539 | return -EINVAL; | |
540 | } | |
541 | ||
542 | mutex_lock(&sysfs_lock); | |
543 | ||
544 | spin_lock_irqsave(&gpio_lock, flags); | |
545 | if (!test_bit(FLAG_REQUESTED, &desc->flags) || | |
546 | test_bit(FLAG_EXPORT, &desc->flags)) { | |
547 | spin_unlock_irqrestore(&gpio_lock, flags); | |
548 | gpiod_dbg(desc, "%s: unavailable (requested=%d, exported=%d)\n", | |
549 | __func__, | |
550 | test_bit(FLAG_REQUESTED, &desc->flags), | |
551 | test_bit(FLAG_EXPORT, &desc->flags)); | |
552 | status = -EPERM; | |
553 | goto fail_unlock; | |
554 | } | |
555 | ||
556 | if (!desc->chip->direction_input || !desc->chip->direction_output) | |
557 | direction_may_change = false; | |
558 | spin_unlock_irqrestore(&gpio_lock, flags); | |
559 | ||
560 | offset = gpio_chip_hwgpio(desc); | |
561 | if (desc->chip->names && desc->chip->names[offset]) | |
562 | ioname = desc->chip->names[offset]; | |
563 | ||
564 | dev = device_create(&gpio_class, desc->chip->dev, MKDEV(0, 0), | |
565 | desc, ioname ? ioname : "gpio%u", | |
566 | desc_to_gpio(desc)); | |
567 | if (IS_ERR(dev)) { | |
568 | status = PTR_ERR(dev); | |
569 | goto fail_unlock; | |
570 | } | |
571 | ||
572 | status = sysfs_create_group(&dev->kobj, &gpio_attr_group); | |
573 | if (status) | |
574 | goto fail_unregister_device; | |
575 | ||
576 | if (direction_may_change) { | |
577 | status = device_create_file(dev, &dev_attr_direction); | |
578 | if (status) | |
579 | goto fail_unregister_device; | |
580 | } | |
581 | ||
582 | if (gpiod_to_irq(desc) >= 0 && (direction_may_change || | |
583 | !test_bit(FLAG_IS_OUT, &desc->flags))) { | |
584 | status = device_create_file(dev, &dev_attr_edge); | |
585 | if (status) | |
586 | goto fail_unregister_device; | |
587 | } | |
588 | ||
589 | set_bit(FLAG_EXPORT, &desc->flags); | |
590 | mutex_unlock(&sysfs_lock); | |
591 | return 0; | |
592 | ||
593 | fail_unregister_device: | |
594 | device_unregister(dev); | |
595 | fail_unlock: | |
596 | mutex_unlock(&sysfs_lock); | |
597 | gpiod_dbg(desc, "%s: status %d\n", __func__, status); | |
598 | return status; | |
599 | } | |
600 | EXPORT_SYMBOL_GPL(gpiod_export); | |
601 | ||
602 | static int match_export(struct device *dev, const void *data) | |
603 | { | |
604 | return dev_get_drvdata(dev) == data; | |
605 | } | |
606 | ||
607 | /** | |
608 | * gpiod_export_link - create a sysfs link to an exported GPIO node | |
609 | * @dev: device under which to create symlink | |
610 | * @name: name of the symlink | |
611 | * @gpio: gpio to create symlink to, already exported | |
612 | * | |
613 | * Set up a symlink from /sys/.../dev/name to /sys/class/gpio/gpioN | |
614 | * node. Caller is responsible for unlinking. | |
615 | * | |
616 | * Returns zero on success, else an error. | |
617 | */ | |
618 | int gpiod_export_link(struct device *dev, const char *name, | |
619 | struct gpio_desc *desc) | |
620 | { | |
621 | int status = -EINVAL; | |
622 | ||
623 | if (!desc) { | |
624 | pr_warn("%s: invalid GPIO\n", __func__); | |
625 | return -EINVAL; | |
626 | } | |
627 | ||
628 | mutex_lock(&sysfs_lock); | |
629 | ||
630 | if (test_bit(FLAG_EXPORT, &desc->flags)) { | |
631 | struct device *tdev; | |
632 | ||
633 | tdev = class_find_device(&gpio_class, NULL, desc, match_export); | |
634 | if (tdev != NULL) { | |
635 | status = sysfs_create_link(&dev->kobj, &tdev->kobj, | |
636 | name); | |
637 | } else { | |
638 | status = -ENODEV; | |
639 | } | |
640 | } | |
641 | ||
642 | mutex_unlock(&sysfs_lock); | |
643 | ||
644 | if (status) | |
645 | gpiod_dbg(desc, "%s: status %d\n", __func__, status); | |
646 | ||
647 | return status; | |
648 | } | |
649 | EXPORT_SYMBOL_GPL(gpiod_export_link); | |
650 | ||
651 | /** | |
652 | * gpiod_sysfs_set_active_low - set the polarity of gpio sysfs value | |
653 | * @gpio: gpio to change | |
654 | * @value: non-zero to use active low, i.e. inverted values | |
655 | * | |
656 | * Set the polarity of /sys/class/gpio/gpioN/value sysfs attribute. | |
657 | * The GPIO does not have to be exported yet. If poll(2) support has | |
658 | * been enabled for either rising or falling edge, it will be | |
659 | * reconfigured to follow the new polarity. | |
660 | * | |
661 | * Returns zero on success, else an error. | |
662 | */ | |
663 | int gpiod_sysfs_set_active_low(struct gpio_desc *desc, int value) | |
664 | { | |
665 | struct device *dev = NULL; | |
666 | int status = -EINVAL; | |
667 | ||
668 | if (!desc) { | |
669 | pr_warn("%s: invalid GPIO\n", __func__); | |
670 | return -EINVAL; | |
671 | } | |
672 | ||
673 | mutex_lock(&sysfs_lock); | |
674 | ||
675 | if (test_bit(FLAG_EXPORT, &desc->flags)) { | |
676 | dev = class_find_device(&gpio_class, NULL, desc, match_export); | |
677 | if (dev == NULL) { | |
678 | status = -ENODEV; | |
679 | goto unlock; | |
680 | } | |
681 | } | |
682 | ||
683 | status = sysfs_set_active_low(desc, dev, value); | |
684 | ||
685 | unlock: | |
686 | mutex_unlock(&sysfs_lock); | |
687 | ||
688 | if (status) | |
689 | gpiod_dbg(desc, "%s: status %d\n", __func__, status); | |
690 | ||
691 | return status; | |
692 | } | |
693 | EXPORT_SYMBOL_GPL(gpiod_sysfs_set_active_low); | |
694 | ||
695 | /** | |
696 | * gpiod_unexport - reverse effect of gpio_export() | |
697 | * @gpio: gpio to make unavailable | |
698 | * | |
699 | * This is implicit on gpio_free(). | |
700 | */ | |
701 | void gpiod_unexport(struct gpio_desc *desc) | |
702 | { | |
703 | int status = 0; | |
704 | struct device *dev = NULL; | |
705 | ||
706 | if (!desc) { | |
707 | pr_warn("%s: invalid GPIO\n", __func__); | |
708 | return; | |
709 | } | |
710 | ||
711 | mutex_lock(&sysfs_lock); | |
712 | ||
713 | if (test_bit(FLAG_EXPORT, &desc->flags)) { | |
714 | ||
715 | dev = class_find_device(&gpio_class, NULL, desc, match_export); | |
716 | if (dev) { | |
717 | gpio_setup_irq(desc, dev, 0); | |
718 | clear_bit(FLAG_EXPORT, &desc->flags); | |
719 | } else | |
720 | status = -ENODEV; | |
721 | } | |
722 | ||
723 | mutex_unlock(&sysfs_lock); | |
724 | ||
725 | if (dev) { | |
726 | device_unregister(dev); | |
727 | put_device(dev); | |
728 | } | |
729 | ||
730 | if (status) | |
731 | gpiod_dbg(desc, "%s: status %d\n", __func__, status); | |
732 | } | |
733 | EXPORT_SYMBOL_GPL(gpiod_unexport); | |
734 | ||
735 | int gpiochip_export(struct gpio_chip *chip) | |
736 | { | |
737 | int status; | |
738 | struct device *dev; | |
739 | ||
740 | /* Many systems register gpio chips for SOC support very early, | |
741 | * before driver model support is available. In those cases we | |
742 | * export this later, in gpiolib_sysfs_init() ... here we just | |
743 | * verify that _some_ field of gpio_class got initialized. | |
744 | */ | |
745 | if (!gpio_class.p) | |
746 | return 0; | |
747 | ||
748 | /* use chip->base for the ID; it's already known to be unique */ | |
749 | mutex_lock(&sysfs_lock); | |
121b6a79 JH |
750 | dev = device_create_with_groups(&gpio_class, chip->dev, MKDEV(0, 0), |
751 | chip, gpiochip_groups, | |
752 | "gpiochip%d", chip->base); | |
753 | if (IS_ERR(dev)) | |
0eb4c6c2 | 754 | status = PTR_ERR(dev); |
121b6a79 JH |
755 | else |
756 | status = 0; | |
0eb4c6c2 AC |
757 | chip->exported = (status == 0); |
758 | mutex_unlock(&sysfs_lock); | |
759 | ||
14141a93 | 760 | if (status) |
0eb4c6c2 | 761 | chip_dbg(chip, "%s: status %d\n", __func__, status); |
0eb4c6c2 AC |
762 | |
763 | return status; | |
764 | } | |
765 | ||
766 | void gpiochip_unexport(struct gpio_chip *chip) | |
767 | { | |
768 | int status; | |
769 | struct device *dev; | |
770 | ||
771 | mutex_lock(&sysfs_lock); | |
772 | dev = class_find_device(&gpio_class, NULL, chip, match_export); | |
773 | if (dev) { | |
774 | put_device(dev); | |
775 | device_unregister(dev); | |
776 | chip->exported = false; | |
777 | status = 0; | |
778 | } else | |
779 | status = -ENODEV; | |
780 | mutex_unlock(&sysfs_lock); | |
781 | ||
782 | if (status) | |
783 | chip_dbg(chip, "%s: status %d\n", __func__, status); | |
784 | } | |
785 | ||
786 | static int __init gpiolib_sysfs_init(void) | |
787 | { | |
788 | int status; | |
789 | unsigned long flags; | |
790 | struct gpio_chip *chip; | |
791 | ||
792 | status = class_register(&gpio_class); | |
793 | if (status < 0) | |
794 | return status; | |
795 | ||
796 | /* Scan and register the gpio_chips which registered very | |
797 | * early (e.g. before the class_register above was called). | |
798 | * | |
799 | * We run before arch_initcall() so chip->dev nodes can have | |
800 | * registered, and so arch_initcall() can always gpio_export(). | |
801 | */ | |
802 | spin_lock_irqsave(&gpio_lock, flags); | |
803 | list_for_each_entry(chip, &gpio_chips, list) { | |
7fd834ad | 804 | if (chip->exported) |
0eb4c6c2 AC |
805 | continue; |
806 | ||
14141a93 AC |
807 | /* |
808 | * TODO we yield gpio_lock here because gpiochip_export() | |
809 | * acquires a mutex. This is unsafe and needs to be fixed. | |
810 | * | |
811 | * Also it would be nice to use gpiochip_find() here so we | |
812 | * can keep gpio_chips local to gpiolib.c, but the yield of | |
813 | * gpio_lock prevents us from doing this. | |
814 | */ | |
0eb4c6c2 AC |
815 | spin_unlock_irqrestore(&gpio_lock, flags); |
816 | status = gpiochip_export(chip); | |
817 | spin_lock_irqsave(&gpio_lock, flags); | |
818 | } | |
819 | spin_unlock_irqrestore(&gpio_lock, flags); | |
820 | ||
821 | ||
822 | return status; | |
823 | } | |
824 | postcore_initcall(gpiolib_sysfs_init); |