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d2876d08 DB |
1 | #include <linux/kernel.h> |
2 | #include <linux/module.h> | |
3 | #include <linux/irq.h> | |
4 | #include <linux/spinlock.h> | |
d8f388d8 DB |
5 | #include <linux/device.h> |
6 | #include <linux/err.h> | |
7 | #include <linux/debugfs.h> | |
8 | #include <linux/seq_file.h> | |
9 | #include <linux/gpio.h> | |
d2876d08 DB |
10 | |
11 | ||
12 | /* Optional implementation infrastructure for GPIO interfaces. | |
13 | * | |
14 | * Platforms may want to use this if they tend to use very many GPIOs | |
15 | * that aren't part of a System-On-Chip core; or across I2C/SPI/etc. | |
16 | * | |
17 | * When kernel footprint or instruction count is an issue, simpler | |
18 | * implementations may be preferred. The GPIO programming interface | |
19 | * allows for inlining speed-critical get/set operations for common | |
20 | * cases, so that access to SOC-integrated GPIOs can sometimes cost | |
21 | * only an instruction or two per bit. | |
22 | */ | |
23 | ||
24 | ||
25 | /* When debugging, extend minimal trust to callers and platform code. | |
26 | * Also emit diagnostic messages that may help initial bringup, when | |
27 | * board setup or driver bugs are most common. | |
28 | * | |
29 | * Otherwise, minimize overhead in what may be bitbanging codepaths. | |
30 | */ | |
31 | #ifdef DEBUG | |
32 | #define extra_checks 1 | |
33 | #else | |
34 | #define extra_checks 0 | |
35 | #endif | |
36 | ||
37 | /* gpio_lock prevents conflicts during gpio_desc[] table updates. | |
38 | * While any GPIO is requested, its gpio_chip is not removable; | |
39 | * each GPIO's "requested" flag serves as a lock and refcount. | |
40 | */ | |
41 | static DEFINE_SPINLOCK(gpio_lock); | |
42 | ||
43 | struct gpio_desc { | |
44 | struct gpio_chip *chip; | |
45 | unsigned long flags; | |
46 | /* flag symbols are bit numbers */ | |
47 | #define FLAG_REQUESTED 0 | |
48 | #define FLAG_IS_OUT 1 | |
169b6a7a | 49 | #define FLAG_RESERVED 2 |
d8f388d8 DB |
50 | #define FLAG_EXPORT 3 /* protected by sysfs_lock */ |
51 | #define FLAG_SYSFS 4 /* exported via /sys/class/gpio/control */ | |
d2876d08 DB |
52 | |
53 | #ifdef CONFIG_DEBUG_FS | |
54 | const char *label; | |
55 | #endif | |
56 | }; | |
57 | static struct gpio_desc gpio_desc[ARCH_NR_GPIOS]; | |
58 | ||
59 | static inline void desc_set_label(struct gpio_desc *d, const char *label) | |
60 | { | |
61 | #ifdef CONFIG_DEBUG_FS | |
62 | d->label = label; | |
63 | #endif | |
64 | } | |
65 | ||
66 | /* Warn when drivers omit gpio_request() calls -- legal but ill-advised | |
67 | * when setting direction, and otherwise illegal. Until board setup code | |
68 | * and drivers use explicit requests everywhere (which won't happen when | |
69 | * those calls have no teeth) we can't avoid autorequesting. This nag | |
35e8bb51 DB |
70 | * message should motivate switching to explicit requests... so should |
71 | * the weaker cleanup after faults, compared to gpio_request(). | |
8a0cecff DB |
72 | * |
73 | * NOTE: the autorequest mechanism is going away; at this point it's | |
74 | * only "legal" in the sense that (old) code using it won't break yet, | |
75 | * but instead only triggers a WARN() stack dump. | |
d2876d08 | 76 | */ |
35e8bb51 | 77 | static int gpio_ensure_requested(struct gpio_desc *desc, unsigned offset) |
d2876d08 | 78 | { |
8a0cecff DB |
79 | const struct gpio_chip *chip = desc->chip; |
80 | const int gpio = chip->base + offset; | |
35e8bb51 | 81 | |
8a0cecff DB |
82 | if (WARN(test_and_set_bit(FLAG_REQUESTED, &desc->flags) == 0, |
83 | "autorequest GPIO-%d\n", gpio)) { | |
35e8bb51 DB |
84 | if (!try_module_get(chip->owner)) { |
85 | pr_err("GPIO-%d: module can't be gotten \n", gpio); | |
86 | clear_bit(FLAG_REQUESTED, &desc->flags); | |
87 | /* lose */ | |
88 | return -EIO; | |
89 | } | |
d2876d08 | 90 | desc_set_label(desc, "[auto]"); |
35e8bb51 DB |
91 | /* caller must chip->request() w/o spinlock */ |
92 | if (chip->request) | |
93 | return 1; | |
d2876d08 | 94 | } |
35e8bb51 | 95 | return 0; |
d2876d08 DB |
96 | } |
97 | ||
98 | /* caller holds gpio_lock *OR* gpio is marked as requested */ | |
99 | static inline struct gpio_chip *gpio_to_chip(unsigned gpio) | |
100 | { | |
101 | return gpio_desc[gpio].chip; | |
102 | } | |
103 | ||
8d0aab2f AV |
104 | /* dynamic allocation of GPIOs, e.g. on a hotplugged device */ |
105 | static int gpiochip_find_base(int ngpio) | |
106 | { | |
107 | int i; | |
108 | int spare = 0; | |
109 | int base = -ENOSPC; | |
110 | ||
111 | for (i = ARCH_NR_GPIOS - 1; i >= 0 ; i--) { | |
169b6a7a AV |
112 | struct gpio_desc *desc = &gpio_desc[i]; |
113 | struct gpio_chip *chip = desc->chip; | |
8d0aab2f | 114 | |
169b6a7a | 115 | if (!chip && !test_bit(FLAG_RESERVED, &desc->flags)) { |
8d0aab2f AV |
116 | spare++; |
117 | if (spare == ngpio) { | |
118 | base = i; | |
119 | break; | |
120 | } | |
121 | } else { | |
122 | spare = 0; | |
169b6a7a AV |
123 | if (chip) |
124 | i -= chip->ngpio - 1; | |
8d0aab2f AV |
125 | } |
126 | } | |
127 | ||
128 | if (gpio_is_valid(base)) | |
129 | pr_debug("%s: found new base at %d\n", __func__, base); | |
130 | return base; | |
131 | } | |
132 | ||
169b6a7a AV |
133 | /** |
134 | * gpiochip_reserve() - reserve range of gpios to use with platform code only | |
135 | * @start: starting gpio number | |
136 | * @ngpio: number of gpios to reserve | |
137 | * Context: platform init, potentially before irqs or kmalloc will work | |
138 | * | |
139 | * Returns a negative errno if any gpio within the range is already reserved | |
140 | * or registered, else returns zero as a success code. Use this function | |
141 | * to mark a range of gpios as unavailable for dynamic gpio number allocation, | |
142 | * for example because its driver support is not yet loaded. | |
143 | */ | |
144 | int __init gpiochip_reserve(int start, int ngpio) | |
145 | { | |
146 | int ret = 0; | |
147 | unsigned long flags; | |
148 | int i; | |
149 | ||
bff5fda9 | 150 | if (!gpio_is_valid(start) || !gpio_is_valid(start + ngpio - 1)) |
169b6a7a AV |
151 | return -EINVAL; |
152 | ||
153 | spin_lock_irqsave(&gpio_lock, flags); | |
154 | ||
155 | for (i = start; i < start + ngpio; i++) { | |
156 | struct gpio_desc *desc = &gpio_desc[i]; | |
157 | ||
158 | if (desc->chip || test_bit(FLAG_RESERVED, &desc->flags)) { | |
159 | ret = -EBUSY; | |
160 | goto err; | |
161 | } | |
162 | ||
163 | set_bit(FLAG_RESERVED, &desc->flags); | |
164 | } | |
165 | ||
166 | pr_debug("%s: reserved gpios from %d to %d\n", | |
167 | __func__, start, start + ngpio - 1); | |
168 | err: | |
169 | spin_unlock_irqrestore(&gpio_lock, flags); | |
170 | ||
171 | return ret; | |
172 | } | |
173 | ||
d8f388d8 DB |
174 | #ifdef CONFIG_GPIO_SYSFS |
175 | ||
176 | /* lock protects against unexport_gpio() being called while | |
177 | * sysfs files are active. | |
178 | */ | |
179 | static DEFINE_MUTEX(sysfs_lock); | |
180 | ||
181 | /* | |
182 | * /sys/class/gpio/gpioN... only for GPIOs that are exported | |
183 | * /direction | |
184 | * * MAY BE OMITTED if kernel won't allow direction changes | |
185 | * * is read/write as "in" or "out" | |
186 | * * may also be written as "high" or "low", initializing | |
187 | * output value as specified ("out" implies "low") | |
188 | * /value | |
189 | * * always readable, subject to hardware behavior | |
190 | * * may be writable, as zero/nonzero | |
191 | * | |
192 | * REVISIT there will likely be an attribute for configuring async | |
193 | * notifications, e.g. to specify polling interval or IRQ trigger type | |
194 | * that would for example trigger a poll() on the "value". | |
195 | */ | |
196 | ||
197 | static ssize_t gpio_direction_show(struct device *dev, | |
198 | struct device_attribute *attr, char *buf) | |
199 | { | |
200 | const struct gpio_desc *desc = dev_get_drvdata(dev); | |
201 | ssize_t status; | |
202 | ||
203 | mutex_lock(&sysfs_lock); | |
204 | ||
205 | if (!test_bit(FLAG_EXPORT, &desc->flags)) | |
206 | status = -EIO; | |
207 | else | |
208 | status = sprintf(buf, "%s\n", | |
209 | test_bit(FLAG_IS_OUT, &desc->flags) | |
210 | ? "out" : "in"); | |
211 | ||
212 | mutex_unlock(&sysfs_lock); | |
213 | return status; | |
214 | } | |
215 | ||
216 | static ssize_t gpio_direction_store(struct device *dev, | |
217 | struct device_attribute *attr, const char *buf, size_t size) | |
218 | { | |
219 | const struct gpio_desc *desc = dev_get_drvdata(dev); | |
220 | unsigned gpio = desc - gpio_desc; | |
221 | ssize_t status; | |
222 | ||
223 | mutex_lock(&sysfs_lock); | |
224 | ||
225 | if (!test_bit(FLAG_EXPORT, &desc->flags)) | |
226 | status = -EIO; | |
227 | else if (sysfs_streq(buf, "high")) | |
228 | status = gpio_direction_output(gpio, 1); | |
229 | else if (sysfs_streq(buf, "out") || sysfs_streq(buf, "low")) | |
230 | status = gpio_direction_output(gpio, 0); | |
231 | else if (sysfs_streq(buf, "in")) | |
232 | status = gpio_direction_input(gpio); | |
233 | else | |
234 | status = -EINVAL; | |
235 | ||
236 | mutex_unlock(&sysfs_lock); | |
237 | return status ? : size; | |
238 | } | |
239 | ||
240 | static const DEVICE_ATTR(direction, 0644, | |
241 | gpio_direction_show, gpio_direction_store); | |
242 | ||
243 | static ssize_t gpio_value_show(struct device *dev, | |
244 | struct device_attribute *attr, char *buf) | |
245 | { | |
246 | const struct gpio_desc *desc = dev_get_drvdata(dev); | |
247 | unsigned gpio = desc - gpio_desc; | |
248 | ssize_t status; | |
249 | ||
250 | mutex_lock(&sysfs_lock); | |
251 | ||
252 | if (!test_bit(FLAG_EXPORT, &desc->flags)) | |
253 | status = -EIO; | |
254 | else | |
e3274e91 | 255 | status = sprintf(buf, "%d\n", !!gpio_get_value_cansleep(gpio)); |
d8f388d8 DB |
256 | |
257 | mutex_unlock(&sysfs_lock); | |
258 | return status; | |
259 | } | |
260 | ||
261 | static ssize_t gpio_value_store(struct device *dev, | |
262 | struct device_attribute *attr, const char *buf, size_t size) | |
263 | { | |
264 | const struct gpio_desc *desc = dev_get_drvdata(dev); | |
265 | unsigned gpio = desc - gpio_desc; | |
266 | ssize_t status; | |
267 | ||
268 | mutex_lock(&sysfs_lock); | |
269 | ||
270 | if (!test_bit(FLAG_EXPORT, &desc->flags)) | |
271 | status = -EIO; | |
272 | else if (!test_bit(FLAG_IS_OUT, &desc->flags)) | |
273 | status = -EPERM; | |
274 | else { | |
275 | long value; | |
276 | ||
277 | status = strict_strtol(buf, 0, &value); | |
278 | if (status == 0) { | |
279 | gpio_set_value_cansleep(gpio, value != 0); | |
280 | status = size; | |
281 | } | |
282 | } | |
283 | ||
284 | mutex_unlock(&sysfs_lock); | |
285 | return status; | |
286 | } | |
287 | ||
288 | static /*const*/ DEVICE_ATTR(value, 0644, | |
289 | gpio_value_show, gpio_value_store); | |
290 | ||
291 | static const struct attribute *gpio_attrs[] = { | |
292 | &dev_attr_direction.attr, | |
293 | &dev_attr_value.attr, | |
294 | NULL, | |
295 | }; | |
296 | ||
297 | static const struct attribute_group gpio_attr_group = { | |
298 | .attrs = (struct attribute **) gpio_attrs, | |
299 | }; | |
300 | ||
301 | /* | |
302 | * /sys/class/gpio/gpiochipN/ | |
303 | * /base ... matching gpio_chip.base (N) | |
304 | * /label ... matching gpio_chip.label | |
305 | * /ngpio ... matching gpio_chip.ngpio | |
306 | */ | |
307 | ||
308 | static ssize_t chip_base_show(struct device *dev, | |
309 | struct device_attribute *attr, char *buf) | |
310 | { | |
311 | const struct gpio_chip *chip = dev_get_drvdata(dev); | |
312 | ||
313 | return sprintf(buf, "%d\n", chip->base); | |
314 | } | |
315 | static DEVICE_ATTR(base, 0444, chip_base_show, NULL); | |
316 | ||
317 | static ssize_t chip_label_show(struct device *dev, | |
318 | struct device_attribute *attr, char *buf) | |
319 | { | |
320 | const struct gpio_chip *chip = dev_get_drvdata(dev); | |
321 | ||
322 | return sprintf(buf, "%s\n", chip->label ? : ""); | |
323 | } | |
324 | static DEVICE_ATTR(label, 0444, chip_label_show, NULL); | |
325 | ||
326 | static ssize_t chip_ngpio_show(struct device *dev, | |
327 | struct device_attribute *attr, char *buf) | |
328 | { | |
329 | const struct gpio_chip *chip = dev_get_drvdata(dev); | |
330 | ||
331 | return sprintf(buf, "%u\n", chip->ngpio); | |
332 | } | |
333 | static DEVICE_ATTR(ngpio, 0444, chip_ngpio_show, NULL); | |
334 | ||
335 | static const struct attribute *gpiochip_attrs[] = { | |
336 | &dev_attr_base.attr, | |
337 | &dev_attr_label.attr, | |
338 | &dev_attr_ngpio.attr, | |
339 | NULL, | |
340 | }; | |
341 | ||
342 | static const struct attribute_group gpiochip_attr_group = { | |
343 | .attrs = (struct attribute **) gpiochip_attrs, | |
344 | }; | |
345 | ||
346 | /* | |
347 | * /sys/class/gpio/export ... write-only | |
348 | * integer N ... number of GPIO to export (full access) | |
349 | * /sys/class/gpio/unexport ... write-only | |
350 | * integer N ... number of GPIO to unexport | |
351 | */ | |
352 | static ssize_t export_store(struct class *class, const char *buf, size_t len) | |
353 | { | |
354 | long gpio; | |
355 | int status; | |
356 | ||
357 | status = strict_strtol(buf, 0, &gpio); | |
358 | if (status < 0) | |
359 | goto done; | |
360 | ||
361 | /* No extra locking here; FLAG_SYSFS just signifies that the | |
362 | * request and export were done by on behalf of userspace, so | |
363 | * they may be undone on its behalf too. | |
364 | */ | |
365 | ||
366 | status = gpio_request(gpio, "sysfs"); | |
367 | if (status < 0) | |
368 | goto done; | |
369 | ||
370 | status = gpio_export(gpio, true); | |
371 | if (status < 0) | |
372 | gpio_free(gpio); | |
373 | else | |
374 | set_bit(FLAG_SYSFS, &gpio_desc[gpio].flags); | |
375 | ||
376 | done: | |
377 | if (status) | |
378 | pr_debug("%s: status %d\n", __func__, status); | |
379 | return status ? : len; | |
380 | } | |
381 | ||
382 | static ssize_t unexport_store(struct class *class, const char *buf, size_t len) | |
383 | { | |
384 | long gpio; | |
385 | int status; | |
386 | ||
387 | status = strict_strtol(buf, 0, &gpio); | |
388 | if (status < 0) | |
389 | goto done; | |
390 | ||
391 | status = -EINVAL; | |
392 | ||
393 | /* reject bogus commands (gpio_unexport ignores them) */ | |
394 | if (!gpio_is_valid(gpio)) | |
395 | goto done; | |
396 | ||
397 | /* No extra locking here; FLAG_SYSFS just signifies that the | |
398 | * request and export were done by on behalf of userspace, so | |
399 | * they may be undone on its behalf too. | |
400 | */ | |
401 | if (test_and_clear_bit(FLAG_SYSFS, &gpio_desc[gpio].flags)) { | |
402 | status = 0; | |
403 | gpio_free(gpio); | |
404 | } | |
405 | done: | |
406 | if (status) | |
407 | pr_debug("%s: status %d\n", __func__, status); | |
408 | return status ? : len; | |
409 | } | |
410 | ||
411 | static struct class_attribute gpio_class_attrs[] = { | |
412 | __ATTR(export, 0200, NULL, export_store), | |
413 | __ATTR(unexport, 0200, NULL, unexport_store), | |
414 | __ATTR_NULL, | |
415 | }; | |
416 | ||
417 | static struct class gpio_class = { | |
418 | .name = "gpio", | |
419 | .owner = THIS_MODULE, | |
420 | ||
421 | .class_attrs = gpio_class_attrs, | |
422 | }; | |
423 | ||
424 | ||
425 | /** | |
426 | * gpio_export - export a GPIO through sysfs | |
427 | * @gpio: gpio to make available, already requested | |
428 | * @direction_may_change: true if userspace may change gpio direction | |
429 | * Context: arch_initcall or later | |
430 | * | |
431 | * When drivers want to make a GPIO accessible to userspace after they | |
432 | * have requested it -- perhaps while debugging, or as part of their | |
433 | * public interface -- they may use this routine. If the GPIO can | |
434 | * change direction (some can't) and the caller allows it, userspace | |
435 | * will see "direction" sysfs attribute which may be used to change | |
436 | * the gpio's direction. A "value" attribute will always be provided. | |
437 | * | |
438 | * Returns zero on success, else an error. | |
439 | */ | |
440 | int gpio_export(unsigned gpio, bool direction_may_change) | |
441 | { | |
442 | unsigned long flags; | |
443 | struct gpio_desc *desc; | |
444 | int status = -EINVAL; | |
926b663c | 445 | char *ioname = NULL; |
d8f388d8 DB |
446 | |
447 | /* can't export until sysfs is available ... */ | |
448 | if (!gpio_class.p) { | |
449 | pr_debug("%s: called too early!\n", __func__); | |
450 | return -ENOENT; | |
451 | } | |
452 | ||
453 | if (!gpio_is_valid(gpio)) | |
454 | goto done; | |
455 | ||
456 | mutex_lock(&sysfs_lock); | |
457 | ||
458 | spin_lock_irqsave(&gpio_lock, flags); | |
459 | desc = &gpio_desc[gpio]; | |
460 | if (test_bit(FLAG_REQUESTED, &desc->flags) | |
461 | && !test_bit(FLAG_EXPORT, &desc->flags)) { | |
462 | status = 0; | |
463 | if (!desc->chip->direction_input | |
464 | || !desc->chip->direction_output) | |
465 | direction_may_change = false; | |
466 | } | |
467 | spin_unlock_irqrestore(&gpio_lock, flags); | |
468 | ||
926b663c DS |
469 | if (desc->chip->names && desc->chip->names[gpio - desc->chip->base]) |
470 | ioname = desc->chip->names[gpio - desc->chip->base]; | |
471 | ||
d8f388d8 DB |
472 | if (status == 0) { |
473 | struct device *dev; | |
474 | ||
475 | dev = device_create(&gpio_class, desc->chip->dev, MKDEV(0, 0), | |
926b663c | 476 | desc, ioname ? ioname : "gpio%d", gpio); |
d8f388d8 DB |
477 | if (dev) { |
478 | if (direction_may_change) | |
479 | status = sysfs_create_group(&dev->kobj, | |
480 | &gpio_attr_group); | |
481 | else | |
482 | status = device_create_file(dev, | |
483 | &dev_attr_value); | |
484 | if (status != 0) | |
485 | device_unregister(dev); | |
486 | } else | |
487 | status = -ENODEV; | |
488 | if (status == 0) | |
489 | set_bit(FLAG_EXPORT, &desc->flags); | |
490 | } | |
491 | ||
492 | mutex_unlock(&sysfs_lock); | |
493 | ||
494 | done: | |
495 | if (status) | |
496 | pr_debug("%s: gpio%d status %d\n", __func__, gpio, status); | |
497 | ||
498 | return status; | |
499 | } | |
500 | EXPORT_SYMBOL_GPL(gpio_export); | |
501 | ||
502 | static int match_export(struct device *dev, void *data) | |
503 | { | |
504 | return dev_get_drvdata(dev) == data; | |
505 | } | |
506 | ||
507 | /** | |
508 | * gpio_unexport - reverse effect of gpio_export() | |
509 | * @gpio: gpio to make unavailable | |
510 | * | |
511 | * This is implicit on gpio_free(). | |
512 | */ | |
513 | void gpio_unexport(unsigned gpio) | |
514 | { | |
515 | struct gpio_desc *desc; | |
516 | int status = -EINVAL; | |
517 | ||
518 | if (!gpio_is_valid(gpio)) | |
519 | goto done; | |
520 | ||
521 | mutex_lock(&sysfs_lock); | |
522 | ||
523 | desc = &gpio_desc[gpio]; | |
926b663c | 524 | |
d8f388d8 DB |
525 | if (test_bit(FLAG_EXPORT, &desc->flags)) { |
526 | struct device *dev = NULL; | |
527 | ||
528 | dev = class_find_device(&gpio_class, NULL, desc, match_export); | |
529 | if (dev) { | |
530 | clear_bit(FLAG_EXPORT, &desc->flags); | |
531 | put_device(dev); | |
532 | device_unregister(dev); | |
533 | status = 0; | |
534 | } else | |
535 | status = -ENODEV; | |
536 | } | |
537 | ||
538 | mutex_unlock(&sysfs_lock); | |
539 | done: | |
540 | if (status) | |
541 | pr_debug("%s: gpio%d status %d\n", __func__, gpio, status); | |
542 | } | |
543 | EXPORT_SYMBOL_GPL(gpio_unexport); | |
544 | ||
545 | static int gpiochip_export(struct gpio_chip *chip) | |
546 | { | |
547 | int status; | |
548 | struct device *dev; | |
549 | ||
550 | /* Many systems register gpio chips for SOC support very early, | |
551 | * before driver model support is available. In those cases we | |
552 | * export this later, in gpiolib_sysfs_init() ... here we just | |
553 | * verify that _some_ field of gpio_class got initialized. | |
554 | */ | |
555 | if (!gpio_class.p) | |
556 | return 0; | |
557 | ||
558 | /* use chip->base for the ID; it's already known to be unique */ | |
559 | mutex_lock(&sysfs_lock); | |
560 | dev = device_create(&gpio_class, chip->dev, MKDEV(0, 0), chip, | |
561 | "gpiochip%d", chip->base); | |
562 | if (dev) { | |
563 | status = sysfs_create_group(&dev->kobj, | |
564 | &gpiochip_attr_group); | |
565 | } else | |
566 | status = -ENODEV; | |
567 | chip->exported = (status == 0); | |
568 | mutex_unlock(&sysfs_lock); | |
569 | ||
570 | if (status) { | |
571 | unsigned long flags; | |
572 | unsigned gpio; | |
573 | ||
574 | spin_lock_irqsave(&gpio_lock, flags); | |
575 | gpio = chip->base; | |
576 | while (gpio_desc[gpio].chip == chip) | |
577 | gpio_desc[gpio++].chip = NULL; | |
578 | spin_unlock_irqrestore(&gpio_lock, flags); | |
579 | ||
580 | pr_debug("%s: chip %s status %d\n", __func__, | |
581 | chip->label, status); | |
582 | } | |
583 | ||
584 | return status; | |
585 | } | |
586 | ||
587 | static void gpiochip_unexport(struct gpio_chip *chip) | |
588 | { | |
589 | int status; | |
590 | struct device *dev; | |
591 | ||
592 | mutex_lock(&sysfs_lock); | |
593 | dev = class_find_device(&gpio_class, NULL, chip, match_export); | |
594 | if (dev) { | |
595 | put_device(dev); | |
596 | device_unregister(dev); | |
597 | chip->exported = 0; | |
598 | status = 0; | |
599 | } else | |
600 | status = -ENODEV; | |
601 | mutex_unlock(&sysfs_lock); | |
602 | ||
603 | if (status) | |
604 | pr_debug("%s: chip %s status %d\n", __func__, | |
605 | chip->label, status); | |
606 | } | |
607 | ||
608 | static int __init gpiolib_sysfs_init(void) | |
609 | { | |
610 | int status; | |
611 | unsigned long flags; | |
612 | unsigned gpio; | |
613 | ||
614 | status = class_register(&gpio_class); | |
615 | if (status < 0) | |
616 | return status; | |
617 | ||
618 | /* Scan and register the gpio_chips which registered very | |
619 | * early (e.g. before the class_register above was called). | |
620 | * | |
621 | * We run before arch_initcall() so chip->dev nodes can have | |
622 | * registered, and so arch_initcall() can always gpio_export(). | |
623 | */ | |
624 | spin_lock_irqsave(&gpio_lock, flags); | |
625 | for (gpio = 0; gpio < ARCH_NR_GPIOS; gpio++) { | |
626 | struct gpio_chip *chip; | |
627 | ||
628 | chip = gpio_desc[gpio].chip; | |
629 | if (!chip || chip->exported) | |
630 | continue; | |
631 | ||
632 | spin_unlock_irqrestore(&gpio_lock, flags); | |
633 | status = gpiochip_export(chip); | |
634 | spin_lock_irqsave(&gpio_lock, flags); | |
635 | } | |
636 | spin_unlock_irqrestore(&gpio_lock, flags); | |
637 | ||
638 | ||
639 | return status; | |
640 | } | |
641 | postcore_initcall(gpiolib_sysfs_init); | |
642 | ||
643 | #else | |
644 | static inline int gpiochip_export(struct gpio_chip *chip) | |
645 | { | |
646 | return 0; | |
647 | } | |
648 | ||
649 | static inline void gpiochip_unexport(struct gpio_chip *chip) | |
650 | { | |
651 | } | |
652 | ||
653 | #endif /* CONFIG_GPIO_SYSFS */ | |
654 | ||
d2876d08 DB |
655 | /** |
656 | * gpiochip_add() - register a gpio_chip | |
657 | * @chip: the chip to register, with chip->base initialized | |
658 | * Context: potentially before irqs or kmalloc will work | |
659 | * | |
660 | * Returns a negative errno if the chip can't be registered, such as | |
661 | * because the chip->base is invalid or already associated with a | |
662 | * different chip. Otherwise it returns zero as a success code. | |
8d0aab2f | 663 | * |
d8f388d8 DB |
664 | * When gpiochip_add() is called very early during boot, so that GPIOs |
665 | * can be freely used, the chip->dev device must be registered before | |
666 | * the gpio framework's arch_initcall(). Otherwise sysfs initialization | |
667 | * for GPIOs will fail rudely. | |
668 | * | |
8d0aab2f AV |
669 | * If chip->base is negative, this requests dynamic assignment of |
670 | * a range of valid GPIOs. | |
d2876d08 DB |
671 | */ |
672 | int gpiochip_add(struct gpio_chip *chip) | |
673 | { | |
674 | unsigned long flags; | |
675 | int status = 0; | |
676 | unsigned id; | |
8d0aab2f | 677 | int base = chip->base; |
d2876d08 | 678 | |
bff5fda9 | 679 | if ((!gpio_is_valid(base) || !gpio_is_valid(base + chip->ngpio - 1)) |
8d0aab2f | 680 | && base >= 0) { |
d2876d08 DB |
681 | status = -EINVAL; |
682 | goto fail; | |
683 | } | |
684 | ||
685 | spin_lock_irqsave(&gpio_lock, flags); | |
686 | ||
8d0aab2f AV |
687 | if (base < 0) { |
688 | base = gpiochip_find_base(chip->ngpio); | |
689 | if (base < 0) { | |
690 | status = base; | |
d8f388d8 | 691 | goto unlock; |
8d0aab2f AV |
692 | } |
693 | chip->base = base; | |
694 | } | |
695 | ||
d2876d08 | 696 | /* these GPIO numbers must not be managed by another gpio_chip */ |
8d0aab2f | 697 | for (id = base; id < base + chip->ngpio; id++) { |
d2876d08 DB |
698 | if (gpio_desc[id].chip != NULL) { |
699 | status = -EBUSY; | |
700 | break; | |
701 | } | |
702 | } | |
703 | if (status == 0) { | |
8d0aab2f | 704 | for (id = base; id < base + chip->ngpio; id++) { |
d2876d08 | 705 | gpio_desc[id].chip = chip; |
d8f388d8 DB |
706 | |
707 | /* REVISIT: most hardware initializes GPIOs as | |
708 | * inputs (often with pullups enabled) so power | |
709 | * usage is minimized. Linux code should set the | |
710 | * gpio direction first thing; but until it does, | |
711 | * we may expose the wrong direction in sysfs. | |
712 | */ | |
713 | gpio_desc[id].flags = !chip->direction_input | |
714 | ? (1 << FLAG_IS_OUT) | |
715 | : 0; | |
d2876d08 DB |
716 | } |
717 | } | |
718 | ||
d8f388d8 | 719 | unlock: |
d2876d08 | 720 | spin_unlock_irqrestore(&gpio_lock, flags); |
d8f388d8 DB |
721 | if (status == 0) |
722 | status = gpiochip_export(chip); | |
d2876d08 DB |
723 | fail: |
724 | /* failures here can mean systems won't boot... */ | |
725 | if (status) | |
726 | pr_err("gpiochip_add: gpios %d..%d (%s) not registered\n", | |
bff5fda9 | 727 | chip->base, chip->base + chip->ngpio - 1, |
d2876d08 DB |
728 | chip->label ? : "generic"); |
729 | return status; | |
730 | } | |
731 | EXPORT_SYMBOL_GPL(gpiochip_add); | |
732 | ||
733 | /** | |
734 | * gpiochip_remove() - unregister a gpio_chip | |
735 | * @chip: the chip to unregister | |
736 | * | |
737 | * A gpio_chip with any GPIOs still requested may not be removed. | |
738 | */ | |
739 | int gpiochip_remove(struct gpio_chip *chip) | |
740 | { | |
741 | unsigned long flags; | |
742 | int status = 0; | |
743 | unsigned id; | |
744 | ||
745 | spin_lock_irqsave(&gpio_lock, flags); | |
746 | ||
747 | for (id = chip->base; id < chip->base + chip->ngpio; id++) { | |
748 | if (test_bit(FLAG_REQUESTED, &gpio_desc[id].flags)) { | |
749 | status = -EBUSY; | |
750 | break; | |
751 | } | |
752 | } | |
753 | if (status == 0) { | |
754 | for (id = chip->base; id < chip->base + chip->ngpio; id++) | |
755 | gpio_desc[id].chip = NULL; | |
756 | } | |
757 | ||
758 | spin_unlock_irqrestore(&gpio_lock, flags); | |
d8f388d8 DB |
759 | |
760 | if (status == 0) | |
761 | gpiochip_unexport(chip); | |
762 | ||
d2876d08 DB |
763 | return status; |
764 | } | |
765 | EXPORT_SYMBOL_GPL(gpiochip_remove); | |
766 | ||
767 | ||
768 | /* These "optional" allocation calls help prevent drivers from stomping | |
769 | * on each other, and help provide better diagnostics in debugfs. | |
770 | * They're called even less than the "set direction" calls. | |
771 | */ | |
772 | int gpio_request(unsigned gpio, const char *label) | |
773 | { | |
774 | struct gpio_desc *desc; | |
35e8bb51 | 775 | struct gpio_chip *chip; |
d2876d08 DB |
776 | int status = -EINVAL; |
777 | unsigned long flags; | |
778 | ||
779 | spin_lock_irqsave(&gpio_lock, flags); | |
780 | ||
e6de1808 | 781 | if (!gpio_is_valid(gpio)) |
d2876d08 DB |
782 | goto done; |
783 | desc = &gpio_desc[gpio]; | |
35e8bb51 DB |
784 | chip = desc->chip; |
785 | if (chip == NULL) | |
d2876d08 DB |
786 | goto done; |
787 | ||
35e8bb51 | 788 | if (!try_module_get(chip->owner)) |
438d8908 GL |
789 | goto done; |
790 | ||
d2876d08 | 791 | /* NOTE: gpio_request() can be called in early boot, |
35e8bb51 | 792 | * before IRQs are enabled, for non-sleeping (SOC) GPIOs. |
d2876d08 DB |
793 | */ |
794 | ||
795 | if (test_and_set_bit(FLAG_REQUESTED, &desc->flags) == 0) { | |
796 | desc_set_label(desc, label ? : "?"); | |
797 | status = 0; | |
438d8908 | 798 | } else { |
d2876d08 | 799 | status = -EBUSY; |
35e8bb51 | 800 | module_put(chip->owner); |
7460db56 | 801 | goto done; |
35e8bb51 DB |
802 | } |
803 | ||
804 | if (chip->request) { | |
805 | /* chip->request may sleep */ | |
806 | spin_unlock_irqrestore(&gpio_lock, flags); | |
807 | status = chip->request(chip, gpio - chip->base); | |
808 | spin_lock_irqsave(&gpio_lock, flags); | |
809 | ||
810 | if (status < 0) { | |
811 | desc_set_label(desc, NULL); | |
812 | module_put(chip->owner); | |
813 | clear_bit(FLAG_REQUESTED, &desc->flags); | |
814 | } | |
438d8908 | 815 | } |
d2876d08 DB |
816 | |
817 | done: | |
818 | if (status) | |
819 | pr_debug("gpio_request: gpio-%d (%s) status %d\n", | |
820 | gpio, label ? : "?", status); | |
821 | spin_unlock_irqrestore(&gpio_lock, flags); | |
822 | return status; | |
823 | } | |
824 | EXPORT_SYMBOL_GPL(gpio_request); | |
825 | ||
826 | void gpio_free(unsigned gpio) | |
827 | { | |
828 | unsigned long flags; | |
829 | struct gpio_desc *desc; | |
35e8bb51 | 830 | struct gpio_chip *chip; |
d2876d08 | 831 | |
3d599d1c UKK |
832 | might_sleep(); |
833 | ||
e6de1808 | 834 | if (!gpio_is_valid(gpio)) { |
d2876d08 DB |
835 | WARN_ON(extra_checks); |
836 | return; | |
837 | } | |
838 | ||
d8f388d8 DB |
839 | gpio_unexport(gpio); |
840 | ||
d2876d08 DB |
841 | spin_lock_irqsave(&gpio_lock, flags); |
842 | ||
843 | desc = &gpio_desc[gpio]; | |
35e8bb51 DB |
844 | chip = desc->chip; |
845 | if (chip && test_bit(FLAG_REQUESTED, &desc->flags)) { | |
846 | if (chip->free) { | |
847 | spin_unlock_irqrestore(&gpio_lock, flags); | |
848 | might_sleep_if(extra_checks && chip->can_sleep); | |
849 | chip->free(chip, gpio - chip->base); | |
850 | spin_lock_irqsave(&gpio_lock, flags); | |
851 | } | |
d2876d08 | 852 | desc_set_label(desc, NULL); |
438d8908 | 853 | module_put(desc->chip->owner); |
35e8bb51 | 854 | clear_bit(FLAG_REQUESTED, &desc->flags); |
438d8908 | 855 | } else |
d2876d08 DB |
856 | WARN_ON(extra_checks); |
857 | ||
858 | spin_unlock_irqrestore(&gpio_lock, flags); | |
859 | } | |
860 | EXPORT_SYMBOL_GPL(gpio_free); | |
861 | ||
862 | ||
863 | /** | |
864 | * gpiochip_is_requested - return string iff signal was requested | |
865 | * @chip: controller managing the signal | |
866 | * @offset: of signal within controller's 0..(ngpio - 1) range | |
867 | * | |
868 | * Returns NULL if the GPIO is not currently requested, else a string. | |
869 | * If debugfs support is enabled, the string returned is the label passed | |
870 | * to gpio_request(); otherwise it is a meaningless constant. | |
871 | * | |
872 | * This function is for use by GPIO controller drivers. The label can | |
873 | * help with diagnostics, and knowing that the signal is used as a GPIO | |
874 | * can help avoid accidentally multiplexing it to another controller. | |
875 | */ | |
876 | const char *gpiochip_is_requested(struct gpio_chip *chip, unsigned offset) | |
877 | { | |
878 | unsigned gpio = chip->base + offset; | |
879 | ||
e6de1808 | 880 | if (!gpio_is_valid(gpio) || gpio_desc[gpio].chip != chip) |
d2876d08 DB |
881 | return NULL; |
882 | if (test_bit(FLAG_REQUESTED, &gpio_desc[gpio].flags) == 0) | |
883 | return NULL; | |
884 | #ifdef CONFIG_DEBUG_FS | |
885 | return gpio_desc[gpio].label; | |
886 | #else | |
887 | return "?"; | |
888 | #endif | |
889 | } | |
890 | EXPORT_SYMBOL_GPL(gpiochip_is_requested); | |
891 | ||
892 | ||
893 | /* Drivers MUST set GPIO direction before making get/set calls. In | |
894 | * some cases this is done in early boot, before IRQs are enabled. | |
895 | * | |
896 | * As a rule these aren't called more than once (except for drivers | |
897 | * using the open-drain emulation idiom) so these are natural places | |
898 | * to accumulate extra debugging checks. Note that we can't (yet) | |
899 | * rely on gpio_request() having been called beforehand. | |
900 | */ | |
901 | ||
902 | int gpio_direction_input(unsigned gpio) | |
903 | { | |
904 | unsigned long flags; | |
905 | struct gpio_chip *chip; | |
906 | struct gpio_desc *desc = &gpio_desc[gpio]; | |
907 | int status = -EINVAL; | |
908 | ||
909 | spin_lock_irqsave(&gpio_lock, flags); | |
910 | ||
e6de1808 | 911 | if (!gpio_is_valid(gpio)) |
d2876d08 DB |
912 | goto fail; |
913 | chip = desc->chip; | |
914 | if (!chip || !chip->get || !chip->direction_input) | |
915 | goto fail; | |
916 | gpio -= chip->base; | |
917 | if (gpio >= chip->ngpio) | |
918 | goto fail; | |
35e8bb51 DB |
919 | status = gpio_ensure_requested(desc, gpio); |
920 | if (status < 0) | |
921 | goto fail; | |
d2876d08 DB |
922 | |
923 | /* now we know the gpio is valid and chip won't vanish */ | |
924 | ||
925 | spin_unlock_irqrestore(&gpio_lock, flags); | |
926 | ||
927 | might_sleep_if(extra_checks && chip->can_sleep); | |
928 | ||
35e8bb51 DB |
929 | if (status) { |
930 | status = chip->request(chip, gpio); | |
931 | if (status < 0) { | |
932 | pr_debug("GPIO-%d: chip request fail, %d\n", | |
933 | chip->base + gpio, status); | |
934 | /* and it's not available to anyone else ... | |
935 | * gpio_request() is the fully clean solution. | |
936 | */ | |
937 | goto lose; | |
938 | } | |
939 | } | |
940 | ||
d2876d08 DB |
941 | status = chip->direction_input(chip, gpio); |
942 | if (status == 0) | |
943 | clear_bit(FLAG_IS_OUT, &desc->flags); | |
35e8bb51 | 944 | lose: |
d2876d08 DB |
945 | return status; |
946 | fail: | |
947 | spin_unlock_irqrestore(&gpio_lock, flags); | |
948 | if (status) | |
949 | pr_debug("%s: gpio-%d status %d\n", | |
145980a0 | 950 | __func__, gpio, status); |
d2876d08 DB |
951 | return status; |
952 | } | |
953 | EXPORT_SYMBOL_GPL(gpio_direction_input); | |
954 | ||
955 | int gpio_direction_output(unsigned gpio, int value) | |
956 | { | |
957 | unsigned long flags; | |
958 | struct gpio_chip *chip; | |
959 | struct gpio_desc *desc = &gpio_desc[gpio]; | |
960 | int status = -EINVAL; | |
961 | ||
962 | spin_lock_irqsave(&gpio_lock, flags); | |
963 | ||
e6de1808 | 964 | if (!gpio_is_valid(gpio)) |
d2876d08 DB |
965 | goto fail; |
966 | chip = desc->chip; | |
967 | if (!chip || !chip->set || !chip->direction_output) | |
968 | goto fail; | |
969 | gpio -= chip->base; | |
970 | if (gpio >= chip->ngpio) | |
971 | goto fail; | |
35e8bb51 DB |
972 | status = gpio_ensure_requested(desc, gpio); |
973 | if (status < 0) | |
974 | goto fail; | |
d2876d08 DB |
975 | |
976 | /* now we know the gpio is valid and chip won't vanish */ | |
977 | ||
978 | spin_unlock_irqrestore(&gpio_lock, flags); | |
979 | ||
980 | might_sleep_if(extra_checks && chip->can_sleep); | |
981 | ||
35e8bb51 DB |
982 | if (status) { |
983 | status = chip->request(chip, gpio); | |
984 | if (status < 0) { | |
985 | pr_debug("GPIO-%d: chip request fail, %d\n", | |
986 | chip->base + gpio, status); | |
987 | /* and it's not available to anyone else ... | |
988 | * gpio_request() is the fully clean solution. | |
989 | */ | |
990 | goto lose; | |
991 | } | |
992 | } | |
993 | ||
d2876d08 DB |
994 | status = chip->direction_output(chip, gpio, value); |
995 | if (status == 0) | |
996 | set_bit(FLAG_IS_OUT, &desc->flags); | |
35e8bb51 | 997 | lose: |
d2876d08 DB |
998 | return status; |
999 | fail: | |
1000 | spin_unlock_irqrestore(&gpio_lock, flags); | |
1001 | if (status) | |
1002 | pr_debug("%s: gpio-%d status %d\n", | |
145980a0 | 1003 | __func__, gpio, status); |
d2876d08 DB |
1004 | return status; |
1005 | } | |
1006 | EXPORT_SYMBOL_GPL(gpio_direction_output); | |
1007 | ||
1008 | ||
1009 | /* I/O calls are only valid after configuration completed; the relevant | |
1010 | * "is this a valid GPIO" error checks should already have been done. | |
1011 | * | |
1012 | * "Get" operations are often inlinable as reading a pin value register, | |
1013 | * and masking the relevant bit in that register. | |
1014 | * | |
1015 | * When "set" operations are inlinable, they involve writing that mask to | |
1016 | * one register to set a low value, or a different register to set it high. | |
1017 | * Otherwise locking is needed, so there may be little value to inlining. | |
1018 | * | |
1019 | *------------------------------------------------------------------------ | |
1020 | * | |
1021 | * IMPORTANT!!! The hot paths -- get/set value -- assume that callers | |
1022 | * have requested the GPIO. That can include implicit requesting by | |
1023 | * a direction setting call. Marking a gpio as requested locks its chip | |
1024 | * in memory, guaranteeing that these table lookups need no more locking | |
1025 | * and that gpiochip_remove() will fail. | |
1026 | * | |
1027 | * REVISIT when debugging, consider adding some instrumentation to ensure | |
1028 | * that the GPIO was actually requested. | |
1029 | */ | |
1030 | ||
1031 | /** | |
1032 | * __gpio_get_value() - return a gpio's value | |
1033 | * @gpio: gpio whose value will be returned | |
1034 | * Context: any | |
1035 | * | |
1036 | * This is used directly or indirectly to implement gpio_get_value(). | |
1037 | * It returns the zero or nonzero value provided by the associated | |
1038 | * gpio_chip.get() method; or zero if no such method is provided. | |
1039 | */ | |
1040 | int __gpio_get_value(unsigned gpio) | |
1041 | { | |
1042 | struct gpio_chip *chip; | |
1043 | ||
1044 | chip = gpio_to_chip(gpio); | |
1045 | WARN_ON(extra_checks && chip->can_sleep); | |
1046 | return chip->get ? chip->get(chip, gpio - chip->base) : 0; | |
1047 | } | |
1048 | EXPORT_SYMBOL_GPL(__gpio_get_value); | |
1049 | ||
1050 | /** | |
1051 | * __gpio_set_value() - assign a gpio's value | |
1052 | * @gpio: gpio whose value will be assigned | |
1053 | * @value: value to assign | |
1054 | * Context: any | |
1055 | * | |
1056 | * This is used directly or indirectly to implement gpio_set_value(). | |
1057 | * It invokes the associated gpio_chip.set() method. | |
1058 | */ | |
1059 | void __gpio_set_value(unsigned gpio, int value) | |
1060 | { | |
1061 | struct gpio_chip *chip; | |
1062 | ||
1063 | chip = gpio_to_chip(gpio); | |
1064 | WARN_ON(extra_checks && chip->can_sleep); | |
1065 | chip->set(chip, gpio - chip->base, value); | |
1066 | } | |
1067 | EXPORT_SYMBOL_GPL(__gpio_set_value); | |
1068 | ||
1069 | /** | |
1070 | * __gpio_cansleep() - report whether gpio value access will sleep | |
1071 | * @gpio: gpio in question | |
1072 | * Context: any | |
1073 | * | |
1074 | * This is used directly or indirectly to implement gpio_cansleep(). It | |
1075 | * returns nonzero if access reading or writing the GPIO value can sleep. | |
1076 | */ | |
1077 | int __gpio_cansleep(unsigned gpio) | |
1078 | { | |
1079 | struct gpio_chip *chip; | |
1080 | ||
1081 | /* only call this on GPIOs that are valid! */ | |
1082 | chip = gpio_to_chip(gpio); | |
1083 | ||
1084 | return chip->can_sleep; | |
1085 | } | |
1086 | EXPORT_SYMBOL_GPL(__gpio_cansleep); | |
1087 | ||
0f6d504e DB |
1088 | /** |
1089 | * __gpio_to_irq() - return the IRQ corresponding to a GPIO | |
1090 | * @gpio: gpio whose IRQ will be returned (already requested) | |
1091 | * Context: any | |
1092 | * | |
1093 | * This is used directly or indirectly to implement gpio_to_irq(). | |
1094 | * It returns the number of the IRQ signaled by this (input) GPIO, | |
1095 | * or a negative errno. | |
1096 | */ | |
1097 | int __gpio_to_irq(unsigned gpio) | |
1098 | { | |
1099 | struct gpio_chip *chip; | |
1100 | ||
1101 | chip = gpio_to_chip(gpio); | |
1102 | return chip->to_irq ? chip->to_irq(chip, gpio - chip->base) : -ENXIO; | |
1103 | } | |
1104 | EXPORT_SYMBOL_GPL(__gpio_to_irq); | |
1105 | ||
d2876d08 DB |
1106 | |
1107 | ||
1108 | /* There's no value in making it easy to inline GPIO calls that may sleep. | |
1109 | * Common examples include ones connected to I2C or SPI chips. | |
1110 | */ | |
1111 | ||
1112 | int gpio_get_value_cansleep(unsigned gpio) | |
1113 | { | |
1114 | struct gpio_chip *chip; | |
1115 | ||
1116 | might_sleep_if(extra_checks); | |
1117 | chip = gpio_to_chip(gpio); | |
978ccaa8 | 1118 | return chip->get ? chip->get(chip, gpio - chip->base) : 0; |
d2876d08 DB |
1119 | } |
1120 | EXPORT_SYMBOL_GPL(gpio_get_value_cansleep); | |
1121 | ||
1122 | void gpio_set_value_cansleep(unsigned gpio, int value) | |
1123 | { | |
1124 | struct gpio_chip *chip; | |
1125 | ||
1126 | might_sleep_if(extra_checks); | |
1127 | chip = gpio_to_chip(gpio); | |
1128 | chip->set(chip, gpio - chip->base, value); | |
1129 | } | |
1130 | EXPORT_SYMBOL_GPL(gpio_set_value_cansleep); | |
1131 | ||
1132 | ||
1133 | #ifdef CONFIG_DEBUG_FS | |
1134 | ||
d2876d08 DB |
1135 | static void gpiolib_dbg_show(struct seq_file *s, struct gpio_chip *chip) |
1136 | { | |
1137 | unsigned i; | |
1138 | unsigned gpio = chip->base; | |
1139 | struct gpio_desc *gdesc = &gpio_desc[gpio]; | |
1140 | int is_out; | |
1141 | ||
1142 | for (i = 0; i < chip->ngpio; i++, gpio++, gdesc++) { | |
1143 | if (!test_bit(FLAG_REQUESTED, &gdesc->flags)) | |
1144 | continue; | |
1145 | ||
1146 | is_out = test_bit(FLAG_IS_OUT, &gdesc->flags); | |
6e8ba729 | 1147 | seq_printf(s, " gpio-%-3d (%-20.20s) %s %s", |
d2876d08 DB |
1148 | gpio, gdesc->label, |
1149 | is_out ? "out" : "in ", | |
1150 | chip->get | |
1151 | ? (chip->get(chip, i) ? "hi" : "lo") | |
1152 | : "? "); | |
1153 | ||
1154 | if (!is_out) { | |
1155 | int irq = gpio_to_irq(gpio); | |
08678b08 | 1156 | struct irq_desc *desc = irq_to_desc(irq); |
d2876d08 DB |
1157 | |
1158 | /* This races with request_irq(), set_irq_type(), | |
1159 | * and set_irq_wake() ... but those are "rare". | |
1160 | * | |
1161 | * More significantly, trigger type flags aren't | |
1162 | * currently maintained by genirq. | |
1163 | */ | |
1164 | if (irq >= 0 && desc->action) { | |
1165 | char *trigger; | |
1166 | ||
1167 | switch (desc->status & IRQ_TYPE_SENSE_MASK) { | |
1168 | case IRQ_TYPE_NONE: | |
1169 | trigger = "(default)"; | |
1170 | break; | |
1171 | case IRQ_TYPE_EDGE_FALLING: | |
1172 | trigger = "edge-falling"; | |
1173 | break; | |
1174 | case IRQ_TYPE_EDGE_RISING: | |
1175 | trigger = "edge-rising"; | |
1176 | break; | |
1177 | case IRQ_TYPE_EDGE_BOTH: | |
1178 | trigger = "edge-both"; | |
1179 | break; | |
1180 | case IRQ_TYPE_LEVEL_HIGH: | |
1181 | trigger = "level-high"; | |
1182 | break; | |
1183 | case IRQ_TYPE_LEVEL_LOW: | |
1184 | trigger = "level-low"; | |
1185 | break; | |
1186 | default: | |
1187 | trigger = "?trigger?"; | |
1188 | break; | |
1189 | } | |
1190 | ||
1191 | seq_printf(s, " irq-%d %s%s", | |
1192 | irq, trigger, | |
1193 | (desc->status & IRQ_WAKEUP) | |
1194 | ? " wakeup" : ""); | |
1195 | } | |
1196 | } | |
1197 | ||
1198 | seq_printf(s, "\n"); | |
1199 | } | |
1200 | } | |
1201 | ||
1202 | static int gpiolib_show(struct seq_file *s, void *unused) | |
1203 | { | |
1204 | struct gpio_chip *chip = NULL; | |
1205 | unsigned gpio; | |
1206 | int started = 0; | |
1207 | ||
1208 | /* REVISIT this isn't locked against gpio_chip removal ... */ | |
1209 | ||
e6de1808 | 1210 | for (gpio = 0; gpio_is_valid(gpio); gpio++) { |
d8f388d8 DB |
1211 | struct device *dev; |
1212 | ||
d2876d08 DB |
1213 | if (chip == gpio_desc[gpio].chip) |
1214 | continue; | |
1215 | chip = gpio_desc[gpio].chip; | |
1216 | if (!chip) | |
1217 | continue; | |
1218 | ||
d8f388d8 | 1219 | seq_printf(s, "%sGPIOs %d-%d", |
d2876d08 | 1220 | started ? "\n" : "", |
d8f388d8 DB |
1221 | chip->base, chip->base + chip->ngpio - 1); |
1222 | dev = chip->dev; | |
1223 | if (dev) | |
1224 | seq_printf(s, ", %s/%s", | |
1225 | dev->bus ? dev->bus->name : "no-bus", | |
14ab309d | 1226 | dev_name(dev)); |
d8f388d8 DB |
1227 | if (chip->label) |
1228 | seq_printf(s, ", %s", chip->label); | |
1229 | if (chip->can_sleep) | |
1230 | seq_printf(s, ", can sleep"); | |
1231 | seq_printf(s, ":\n"); | |
1232 | ||
d2876d08 DB |
1233 | started = 1; |
1234 | if (chip->dbg_show) | |
1235 | chip->dbg_show(s, chip); | |
1236 | else | |
1237 | gpiolib_dbg_show(s, chip); | |
1238 | } | |
1239 | return 0; | |
1240 | } | |
1241 | ||
1242 | static int gpiolib_open(struct inode *inode, struct file *file) | |
1243 | { | |
1244 | return single_open(file, gpiolib_show, NULL); | |
1245 | } | |
1246 | ||
1247 | static struct file_operations gpiolib_operations = { | |
1248 | .open = gpiolib_open, | |
1249 | .read = seq_read, | |
1250 | .llseek = seq_lseek, | |
1251 | .release = single_release, | |
1252 | }; | |
1253 | ||
1254 | static int __init gpiolib_debugfs_init(void) | |
1255 | { | |
1256 | /* /sys/kernel/debug/gpio */ | |
1257 | (void) debugfs_create_file("gpio", S_IFREG | S_IRUGO, | |
1258 | NULL, NULL, &gpiolib_operations); | |
1259 | return 0; | |
1260 | } | |
1261 | subsys_initcall(gpiolib_debugfs_init); | |
1262 | ||
1263 | #endif /* DEBUG_FS */ |