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Commit | Line | Data |
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d2876d08 DB |
1 | #include <linux/kernel.h> |
2 | #include <linux/module.h> | |
ff77c352 | 3 | #include <linux/interrupt.h> |
d2876d08 DB |
4 | #include <linux/irq.h> |
5 | #include <linux/spinlock.h> | |
d8f388d8 DB |
6 | #include <linux/device.h> |
7 | #include <linux/err.h> | |
8 | #include <linux/debugfs.h> | |
9 | #include <linux/seq_file.h> | |
10 | #include <linux/gpio.h> | |
391c970c | 11 | #include <linux/of_gpio.h> |
ff77c352 | 12 | #include <linux/idr.h> |
5a0e3ad6 | 13 | #include <linux/slab.h> |
d2876d08 DB |
14 | |
15 | ||
16 | /* Optional implementation infrastructure for GPIO interfaces. | |
17 | * | |
18 | * Platforms may want to use this if they tend to use very many GPIOs | |
19 | * that aren't part of a System-On-Chip core; or across I2C/SPI/etc. | |
20 | * | |
21 | * When kernel footprint or instruction count is an issue, simpler | |
22 | * implementations may be preferred. The GPIO programming interface | |
23 | * allows for inlining speed-critical get/set operations for common | |
24 | * cases, so that access to SOC-integrated GPIOs can sometimes cost | |
25 | * only an instruction or two per bit. | |
26 | */ | |
27 | ||
28 | ||
29 | /* When debugging, extend minimal trust to callers and platform code. | |
30 | * Also emit diagnostic messages that may help initial bringup, when | |
31 | * board setup or driver bugs are most common. | |
32 | * | |
33 | * Otherwise, minimize overhead in what may be bitbanging codepaths. | |
34 | */ | |
35 | #ifdef DEBUG | |
36 | #define extra_checks 1 | |
37 | #else | |
38 | #define extra_checks 0 | |
39 | #endif | |
40 | ||
41 | /* gpio_lock prevents conflicts during gpio_desc[] table updates. | |
42 | * While any GPIO is requested, its gpio_chip is not removable; | |
43 | * each GPIO's "requested" flag serves as a lock and refcount. | |
44 | */ | |
45 | static DEFINE_SPINLOCK(gpio_lock); | |
46 | ||
47 | struct gpio_desc { | |
48 | struct gpio_chip *chip; | |
49 | unsigned long flags; | |
50 | /* flag symbols are bit numbers */ | |
51 | #define FLAG_REQUESTED 0 | |
52 | #define FLAG_IS_OUT 1 | |
169b6a7a | 53 | #define FLAG_RESERVED 2 |
d8f388d8 DB |
54 | #define FLAG_EXPORT 3 /* protected by sysfs_lock */ |
55 | #define FLAG_SYSFS 4 /* exported via /sys/class/gpio/control */ | |
ff77c352 DG |
56 | #define FLAG_TRIG_FALL 5 /* trigger on falling edge */ |
57 | #define FLAG_TRIG_RISE 6 /* trigger on rising edge */ | |
07697461 | 58 | #define FLAG_ACTIVE_LOW 7 /* sysfs value has active low */ |
ff77c352 | 59 | |
5ba1821d | 60 | #define ID_SHIFT 16 /* add new flags before this one */ |
ff77c352 | 61 | |
5ba1821d | 62 | #define GPIO_FLAGS_MASK ((1 << ID_SHIFT) - 1) |
ff77c352 | 63 | #define GPIO_TRIGGER_MASK (BIT(FLAG_TRIG_FALL) | BIT(FLAG_TRIG_RISE)) |
d2876d08 DB |
64 | |
65 | #ifdef CONFIG_DEBUG_FS | |
66 | const char *label; | |
67 | #endif | |
68 | }; | |
69 | static struct gpio_desc gpio_desc[ARCH_NR_GPIOS]; | |
70 | ||
ff77c352 | 71 | #ifdef CONFIG_GPIO_SYSFS |
5ba1821d | 72 | static DEFINE_IDR(dirent_idr); |
ff77c352 DG |
73 | #endif |
74 | ||
d2876d08 DB |
75 | static inline void desc_set_label(struct gpio_desc *d, const char *label) |
76 | { | |
77 | #ifdef CONFIG_DEBUG_FS | |
78 | d->label = label; | |
79 | #endif | |
80 | } | |
81 | ||
82 | /* Warn when drivers omit gpio_request() calls -- legal but ill-advised | |
83 | * when setting direction, and otherwise illegal. Until board setup code | |
84 | * and drivers use explicit requests everywhere (which won't happen when | |
85 | * those calls have no teeth) we can't avoid autorequesting. This nag | |
35e8bb51 DB |
86 | * message should motivate switching to explicit requests... so should |
87 | * the weaker cleanup after faults, compared to gpio_request(). | |
8a0cecff DB |
88 | * |
89 | * NOTE: the autorequest mechanism is going away; at this point it's | |
90 | * only "legal" in the sense that (old) code using it won't break yet, | |
91 | * but instead only triggers a WARN() stack dump. | |
d2876d08 | 92 | */ |
35e8bb51 | 93 | static int gpio_ensure_requested(struct gpio_desc *desc, unsigned offset) |
d2876d08 | 94 | { |
8a0cecff DB |
95 | const struct gpio_chip *chip = desc->chip; |
96 | const int gpio = chip->base + offset; | |
35e8bb51 | 97 | |
8a0cecff DB |
98 | if (WARN(test_and_set_bit(FLAG_REQUESTED, &desc->flags) == 0, |
99 | "autorequest GPIO-%d\n", gpio)) { | |
35e8bb51 DB |
100 | if (!try_module_get(chip->owner)) { |
101 | pr_err("GPIO-%d: module can't be gotten \n", gpio); | |
102 | clear_bit(FLAG_REQUESTED, &desc->flags); | |
103 | /* lose */ | |
104 | return -EIO; | |
105 | } | |
d2876d08 | 106 | desc_set_label(desc, "[auto]"); |
35e8bb51 DB |
107 | /* caller must chip->request() w/o spinlock */ |
108 | if (chip->request) | |
109 | return 1; | |
d2876d08 | 110 | } |
35e8bb51 | 111 | return 0; |
d2876d08 DB |
112 | } |
113 | ||
114 | /* caller holds gpio_lock *OR* gpio is marked as requested */ | |
115 | static inline struct gpio_chip *gpio_to_chip(unsigned gpio) | |
116 | { | |
117 | return gpio_desc[gpio].chip; | |
118 | } | |
119 | ||
8d0aab2f AV |
120 | /* dynamic allocation of GPIOs, e.g. on a hotplugged device */ |
121 | static int gpiochip_find_base(int ngpio) | |
122 | { | |
123 | int i; | |
124 | int spare = 0; | |
125 | int base = -ENOSPC; | |
126 | ||
127 | for (i = ARCH_NR_GPIOS - 1; i >= 0 ; i--) { | |
169b6a7a AV |
128 | struct gpio_desc *desc = &gpio_desc[i]; |
129 | struct gpio_chip *chip = desc->chip; | |
8d0aab2f | 130 | |
169b6a7a | 131 | if (!chip && !test_bit(FLAG_RESERVED, &desc->flags)) { |
8d0aab2f AV |
132 | spare++; |
133 | if (spare == ngpio) { | |
134 | base = i; | |
135 | break; | |
136 | } | |
137 | } else { | |
138 | spare = 0; | |
169b6a7a AV |
139 | if (chip) |
140 | i -= chip->ngpio - 1; | |
8d0aab2f AV |
141 | } |
142 | } | |
143 | ||
144 | if (gpio_is_valid(base)) | |
145 | pr_debug("%s: found new base at %d\n", __func__, base); | |
146 | return base; | |
147 | } | |
148 | ||
169b6a7a AV |
149 | /** |
150 | * gpiochip_reserve() - reserve range of gpios to use with platform code only | |
151 | * @start: starting gpio number | |
152 | * @ngpio: number of gpios to reserve | |
153 | * Context: platform init, potentially before irqs or kmalloc will work | |
154 | * | |
155 | * Returns a negative errno if any gpio within the range is already reserved | |
156 | * or registered, else returns zero as a success code. Use this function | |
157 | * to mark a range of gpios as unavailable for dynamic gpio number allocation, | |
158 | * for example because its driver support is not yet loaded. | |
159 | */ | |
160 | int __init gpiochip_reserve(int start, int ngpio) | |
161 | { | |
162 | int ret = 0; | |
163 | unsigned long flags; | |
164 | int i; | |
165 | ||
bff5fda9 | 166 | if (!gpio_is_valid(start) || !gpio_is_valid(start + ngpio - 1)) |
169b6a7a AV |
167 | return -EINVAL; |
168 | ||
169 | spin_lock_irqsave(&gpio_lock, flags); | |
170 | ||
171 | for (i = start; i < start + ngpio; i++) { | |
172 | struct gpio_desc *desc = &gpio_desc[i]; | |
173 | ||
174 | if (desc->chip || test_bit(FLAG_RESERVED, &desc->flags)) { | |
175 | ret = -EBUSY; | |
176 | goto err; | |
177 | } | |
178 | ||
179 | set_bit(FLAG_RESERVED, &desc->flags); | |
180 | } | |
181 | ||
182 | pr_debug("%s: reserved gpios from %d to %d\n", | |
183 | __func__, start, start + ngpio - 1); | |
184 | err: | |
185 | spin_unlock_irqrestore(&gpio_lock, flags); | |
186 | ||
187 | return ret; | |
188 | } | |
189 | ||
d8f388d8 DB |
190 | #ifdef CONFIG_GPIO_SYSFS |
191 | ||
192 | /* lock protects against unexport_gpio() being called while | |
193 | * sysfs files are active. | |
194 | */ | |
195 | static DEFINE_MUTEX(sysfs_lock); | |
196 | ||
197 | /* | |
198 | * /sys/class/gpio/gpioN... only for GPIOs that are exported | |
199 | * /direction | |
200 | * * MAY BE OMITTED if kernel won't allow direction changes | |
201 | * * is read/write as "in" or "out" | |
202 | * * may also be written as "high" or "low", initializing | |
203 | * output value as specified ("out" implies "low") | |
204 | * /value | |
205 | * * always readable, subject to hardware behavior | |
206 | * * may be writable, as zero/nonzero | |
ff77c352 DG |
207 | * /edge |
208 | * * configures behavior of poll(2) on /value | |
209 | * * available only if pin can generate IRQs on input | |
210 | * * is read/write as "none", "falling", "rising", or "both" | |
07697461 JN |
211 | * /active_low |
212 | * * configures polarity of /value | |
213 | * * is read/write as zero/nonzero | |
214 | * * also affects existing and subsequent "falling" and "rising" | |
215 | * /edge configuration | |
d8f388d8 DB |
216 | */ |
217 | ||
218 | static ssize_t gpio_direction_show(struct device *dev, | |
219 | struct device_attribute *attr, char *buf) | |
220 | { | |
221 | const struct gpio_desc *desc = dev_get_drvdata(dev); | |
222 | ssize_t status; | |
223 | ||
224 | mutex_lock(&sysfs_lock); | |
225 | ||
226 | if (!test_bit(FLAG_EXPORT, &desc->flags)) | |
227 | status = -EIO; | |
228 | else | |
229 | status = sprintf(buf, "%s\n", | |
230 | test_bit(FLAG_IS_OUT, &desc->flags) | |
231 | ? "out" : "in"); | |
232 | ||
233 | mutex_unlock(&sysfs_lock); | |
234 | return status; | |
235 | } | |
236 | ||
237 | static ssize_t gpio_direction_store(struct device *dev, | |
238 | struct device_attribute *attr, const char *buf, size_t size) | |
239 | { | |
240 | const struct gpio_desc *desc = dev_get_drvdata(dev); | |
241 | unsigned gpio = desc - gpio_desc; | |
242 | ssize_t status; | |
243 | ||
244 | mutex_lock(&sysfs_lock); | |
245 | ||
246 | if (!test_bit(FLAG_EXPORT, &desc->flags)) | |
247 | status = -EIO; | |
248 | else if (sysfs_streq(buf, "high")) | |
249 | status = gpio_direction_output(gpio, 1); | |
250 | else if (sysfs_streq(buf, "out") || sysfs_streq(buf, "low")) | |
251 | status = gpio_direction_output(gpio, 0); | |
252 | else if (sysfs_streq(buf, "in")) | |
253 | status = gpio_direction_input(gpio); | |
254 | else | |
255 | status = -EINVAL; | |
256 | ||
257 | mutex_unlock(&sysfs_lock); | |
258 | return status ? : size; | |
259 | } | |
260 | ||
07697461 | 261 | static /* const */ DEVICE_ATTR(direction, 0644, |
d8f388d8 DB |
262 | gpio_direction_show, gpio_direction_store); |
263 | ||
264 | static ssize_t gpio_value_show(struct device *dev, | |
265 | struct device_attribute *attr, char *buf) | |
266 | { | |
267 | const struct gpio_desc *desc = dev_get_drvdata(dev); | |
268 | unsigned gpio = desc - gpio_desc; | |
269 | ssize_t status; | |
270 | ||
271 | mutex_lock(&sysfs_lock); | |
272 | ||
07697461 | 273 | if (!test_bit(FLAG_EXPORT, &desc->flags)) { |
d8f388d8 | 274 | status = -EIO; |
07697461 JN |
275 | } else { |
276 | int value; | |
277 | ||
278 | value = !!gpio_get_value_cansleep(gpio); | |
279 | if (test_bit(FLAG_ACTIVE_LOW, &desc->flags)) | |
280 | value = !value; | |
281 | ||
282 | status = sprintf(buf, "%d\n", value); | |
283 | } | |
d8f388d8 DB |
284 | |
285 | mutex_unlock(&sysfs_lock); | |
286 | return status; | |
287 | } | |
288 | ||
289 | static ssize_t gpio_value_store(struct device *dev, | |
290 | struct device_attribute *attr, const char *buf, size_t size) | |
291 | { | |
292 | const struct gpio_desc *desc = dev_get_drvdata(dev); | |
293 | unsigned gpio = desc - gpio_desc; | |
294 | ssize_t status; | |
295 | ||
296 | mutex_lock(&sysfs_lock); | |
297 | ||
298 | if (!test_bit(FLAG_EXPORT, &desc->flags)) | |
299 | status = -EIO; | |
300 | else if (!test_bit(FLAG_IS_OUT, &desc->flags)) | |
301 | status = -EPERM; | |
302 | else { | |
303 | long value; | |
304 | ||
305 | status = strict_strtol(buf, 0, &value); | |
306 | if (status == 0) { | |
07697461 JN |
307 | if (test_bit(FLAG_ACTIVE_LOW, &desc->flags)) |
308 | value = !value; | |
d8f388d8 DB |
309 | gpio_set_value_cansleep(gpio, value != 0); |
310 | status = size; | |
311 | } | |
312 | } | |
313 | ||
314 | mutex_unlock(&sysfs_lock); | |
315 | return status; | |
316 | } | |
317 | ||
07697461 | 318 | static const DEVICE_ATTR(value, 0644, |
d8f388d8 DB |
319 | gpio_value_show, gpio_value_store); |
320 | ||
ff77c352 DG |
321 | static irqreturn_t gpio_sysfs_irq(int irq, void *priv) |
322 | { | |
5ba1821d | 323 | struct sysfs_dirent *value_sd = priv; |
ff77c352 | 324 | |
5ba1821d | 325 | sysfs_notify_dirent(value_sd); |
ff77c352 DG |
326 | return IRQ_HANDLED; |
327 | } | |
328 | ||
ff77c352 DG |
329 | static int gpio_setup_irq(struct gpio_desc *desc, struct device *dev, |
330 | unsigned long gpio_flags) | |
331 | { | |
5ba1821d | 332 | struct sysfs_dirent *value_sd; |
ff77c352 DG |
333 | unsigned long irq_flags; |
334 | int ret, irq, id; | |
335 | ||
336 | if ((desc->flags & GPIO_TRIGGER_MASK) == gpio_flags) | |
337 | return 0; | |
338 | ||
339 | irq = gpio_to_irq(desc - gpio_desc); | |
340 | if (irq < 0) | |
341 | return -EIO; | |
342 | ||
5ba1821d DG |
343 | id = desc->flags >> ID_SHIFT; |
344 | value_sd = idr_find(&dirent_idr, id); | |
345 | if (value_sd) | |
346 | free_irq(irq, value_sd); | |
ff77c352 DG |
347 | |
348 | desc->flags &= ~GPIO_TRIGGER_MASK; | |
349 | ||
350 | if (!gpio_flags) { | |
351 | ret = 0; | |
5ba1821d | 352 | goto free_id; |
ff77c352 DG |
353 | } |
354 | ||
355 | irq_flags = IRQF_SHARED; | |
356 | if (test_bit(FLAG_TRIG_FALL, &gpio_flags)) | |
07697461 JN |
357 | irq_flags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ? |
358 | IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING; | |
ff77c352 | 359 | if (test_bit(FLAG_TRIG_RISE, &gpio_flags)) |
07697461 JN |
360 | irq_flags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ? |
361 | IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING; | |
ff77c352 | 362 | |
5ba1821d DG |
363 | if (!value_sd) { |
364 | value_sd = sysfs_get_dirent(dev->kobj.sd, NULL, "value"); | |
365 | if (!value_sd) { | |
366 | ret = -ENODEV; | |
ff77c352 DG |
367 | goto err_out; |
368 | } | |
369 | ||
370 | do { | |
371 | ret = -ENOMEM; | |
5ba1821d DG |
372 | if (idr_pre_get(&dirent_idr, GFP_KERNEL)) |
373 | ret = idr_get_new_above(&dirent_idr, value_sd, | |
374 | 1, &id); | |
ff77c352 DG |
375 | } while (ret == -EAGAIN); |
376 | ||
377 | if (ret) | |
5ba1821d | 378 | goto free_sd; |
ff77c352 DG |
379 | |
380 | desc->flags &= GPIO_FLAGS_MASK; | |
5ba1821d | 381 | desc->flags |= (unsigned long)id << ID_SHIFT; |
ff77c352 | 382 | |
5ba1821d | 383 | if (desc->flags >> ID_SHIFT != id) { |
ff77c352 DG |
384 | ret = -ERANGE; |
385 | goto free_id; | |
386 | } | |
ff77c352 DG |
387 | } |
388 | ||
364fadb3 | 389 | ret = request_any_context_irq(irq, gpio_sysfs_irq, irq_flags, |
5ba1821d | 390 | "gpiolib", value_sd); |
364fadb3 | 391 | if (ret < 0) |
5ba1821d | 392 | goto free_id; |
ff77c352 DG |
393 | |
394 | desc->flags |= gpio_flags; | |
395 | return 0; | |
396 | ||
ff77c352 | 397 | free_id: |
5ba1821d | 398 | idr_remove(&dirent_idr, id); |
ff77c352 | 399 | desc->flags &= GPIO_FLAGS_MASK; |
5ba1821d DG |
400 | free_sd: |
401 | if (value_sd) | |
402 | sysfs_put(value_sd); | |
ff77c352 DG |
403 | err_out: |
404 | return ret; | |
405 | } | |
406 | ||
407 | static const struct { | |
408 | const char *name; | |
409 | unsigned long flags; | |
410 | } trigger_types[] = { | |
411 | { "none", 0 }, | |
412 | { "falling", BIT(FLAG_TRIG_FALL) }, | |
413 | { "rising", BIT(FLAG_TRIG_RISE) }, | |
414 | { "both", BIT(FLAG_TRIG_FALL) | BIT(FLAG_TRIG_RISE) }, | |
415 | }; | |
416 | ||
417 | static ssize_t gpio_edge_show(struct device *dev, | |
418 | struct device_attribute *attr, char *buf) | |
419 | { | |
420 | const struct gpio_desc *desc = dev_get_drvdata(dev); | |
421 | ssize_t status; | |
422 | ||
423 | mutex_lock(&sysfs_lock); | |
424 | ||
425 | if (!test_bit(FLAG_EXPORT, &desc->flags)) | |
426 | status = -EIO; | |
427 | else { | |
428 | int i; | |
429 | ||
430 | status = 0; | |
431 | for (i = 0; i < ARRAY_SIZE(trigger_types); i++) | |
432 | if ((desc->flags & GPIO_TRIGGER_MASK) | |
433 | == trigger_types[i].flags) { | |
434 | status = sprintf(buf, "%s\n", | |
435 | trigger_types[i].name); | |
436 | break; | |
437 | } | |
438 | } | |
439 | ||
440 | mutex_unlock(&sysfs_lock); | |
441 | return status; | |
442 | } | |
443 | ||
444 | static ssize_t gpio_edge_store(struct device *dev, | |
445 | struct device_attribute *attr, const char *buf, size_t size) | |
446 | { | |
447 | struct gpio_desc *desc = dev_get_drvdata(dev); | |
448 | ssize_t status; | |
449 | int i; | |
450 | ||
451 | for (i = 0; i < ARRAY_SIZE(trigger_types); i++) | |
452 | if (sysfs_streq(trigger_types[i].name, buf)) | |
453 | goto found; | |
454 | return -EINVAL; | |
455 | ||
456 | found: | |
457 | mutex_lock(&sysfs_lock); | |
458 | ||
459 | if (!test_bit(FLAG_EXPORT, &desc->flags)) | |
460 | status = -EIO; | |
461 | else { | |
462 | status = gpio_setup_irq(desc, dev, trigger_types[i].flags); | |
463 | if (!status) | |
464 | status = size; | |
465 | } | |
466 | ||
467 | mutex_unlock(&sysfs_lock); | |
468 | ||
469 | return status; | |
470 | } | |
471 | ||
472 | static DEVICE_ATTR(edge, 0644, gpio_edge_show, gpio_edge_store); | |
473 | ||
07697461 JN |
474 | static int sysfs_set_active_low(struct gpio_desc *desc, struct device *dev, |
475 | int value) | |
476 | { | |
477 | int status = 0; | |
478 | ||
479 | if (!!test_bit(FLAG_ACTIVE_LOW, &desc->flags) == !!value) | |
480 | return 0; | |
481 | ||
482 | if (value) | |
483 | set_bit(FLAG_ACTIVE_LOW, &desc->flags); | |
484 | else | |
485 | clear_bit(FLAG_ACTIVE_LOW, &desc->flags); | |
486 | ||
487 | /* reconfigure poll(2) support if enabled on one edge only */ | |
488 | if (dev != NULL && (!!test_bit(FLAG_TRIG_RISE, &desc->flags) ^ | |
489 | !!test_bit(FLAG_TRIG_FALL, &desc->flags))) { | |
490 | unsigned long trigger_flags = desc->flags & GPIO_TRIGGER_MASK; | |
491 | ||
492 | gpio_setup_irq(desc, dev, 0); | |
493 | status = gpio_setup_irq(desc, dev, trigger_flags); | |
494 | } | |
495 | ||
496 | return status; | |
497 | } | |
498 | ||
499 | static ssize_t gpio_active_low_show(struct device *dev, | |
500 | struct device_attribute *attr, char *buf) | |
501 | { | |
502 | const struct gpio_desc *desc = dev_get_drvdata(dev); | |
503 | ssize_t status; | |
504 | ||
505 | mutex_lock(&sysfs_lock); | |
506 | ||
507 | if (!test_bit(FLAG_EXPORT, &desc->flags)) | |
508 | status = -EIO; | |
509 | else | |
510 | status = sprintf(buf, "%d\n", | |
511 | !!test_bit(FLAG_ACTIVE_LOW, &desc->flags)); | |
512 | ||
513 | mutex_unlock(&sysfs_lock); | |
514 | ||
515 | return status; | |
516 | } | |
517 | ||
518 | static ssize_t gpio_active_low_store(struct device *dev, | |
519 | struct device_attribute *attr, const char *buf, size_t size) | |
520 | { | |
521 | struct gpio_desc *desc = dev_get_drvdata(dev); | |
522 | ssize_t status; | |
523 | ||
524 | mutex_lock(&sysfs_lock); | |
525 | ||
526 | if (!test_bit(FLAG_EXPORT, &desc->flags)) { | |
527 | status = -EIO; | |
528 | } else { | |
529 | long value; | |
530 | ||
531 | status = strict_strtol(buf, 0, &value); | |
532 | if (status == 0) | |
533 | status = sysfs_set_active_low(desc, dev, value != 0); | |
534 | } | |
535 | ||
536 | mutex_unlock(&sysfs_lock); | |
537 | ||
538 | return status ? : size; | |
539 | } | |
540 | ||
541 | static const DEVICE_ATTR(active_low, 0644, | |
542 | gpio_active_low_show, gpio_active_low_store); | |
543 | ||
d8f388d8 | 544 | static const struct attribute *gpio_attrs[] = { |
d8f388d8 | 545 | &dev_attr_value.attr, |
07697461 | 546 | &dev_attr_active_low.attr, |
d8f388d8 DB |
547 | NULL, |
548 | }; | |
549 | ||
550 | static const struct attribute_group gpio_attr_group = { | |
551 | .attrs = (struct attribute **) gpio_attrs, | |
552 | }; | |
553 | ||
554 | /* | |
555 | * /sys/class/gpio/gpiochipN/ | |
556 | * /base ... matching gpio_chip.base (N) | |
557 | * /label ... matching gpio_chip.label | |
558 | * /ngpio ... matching gpio_chip.ngpio | |
559 | */ | |
560 | ||
561 | static ssize_t chip_base_show(struct device *dev, | |
562 | struct device_attribute *attr, char *buf) | |
563 | { | |
564 | const struct gpio_chip *chip = dev_get_drvdata(dev); | |
565 | ||
566 | return sprintf(buf, "%d\n", chip->base); | |
567 | } | |
568 | static DEVICE_ATTR(base, 0444, chip_base_show, NULL); | |
569 | ||
570 | static ssize_t chip_label_show(struct device *dev, | |
571 | struct device_attribute *attr, char *buf) | |
572 | { | |
573 | const struct gpio_chip *chip = dev_get_drvdata(dev); | |
574 | ||
575 | return sprintf(buf, "%s\n", chip->label ? : ""); | |
576 | } | |
577 | static DEVICE_ATTR(label, 0444, chip_label_show, NULL); | |
578 | ||
579 | static ssize_t chip_ngpio_show(struct device *dev, | |
580 | struct device_attribute *attr, char *buf) | |
581 | { | |
582 | const struct gpio_chip *chip = dev_get_drvdata(dev); | |
583 | ||
584 | return sprintf(buf, "%u\n", chip->ngpio); | |
585 | } | |
586 | static DEVICE_ATTR(ngpio, 0444, chip_ngpio_show, NULL); | |
587 | ||
588 | static const struct attribute *gpiochip_attrs[] = { | |
589 | &dev_attr_base.attr, | |
590 | &dev_attr_label.attr, | |
591 | &dev_attr_ngpio.attr, | |
592 | NULL, | |
593 | }; | |
594 | ||
595 | static const struct attribute_group gpiochip_attr_group = { | |
596 | .attrs = (struct attribute **) gpiochip_attrs, | |
597 | }; | |
598 | ||
599 | /* | |
600 | * /sys/class/gpio/export ... write-only | |
601 | * integer N ... number of GPIO to export (full access) | |
602 | * /sys/class/gpio/unexport ... write-only | |
603 | * integer N ... number of GPIO to unexport | |
604 | */ | |
28812fe1 AK |
605 | static ssize_t export_store(struct class *class, |
606 | struct class_attribute *attr, | |
607 | const char *buf, size_t len) | |
d8f388d8 DB |
608 | { |
609 | long gpio; | |
610 | int status; | |
611 | ||
612 | status = strict_strtol(buf, 0, &gpio); | |
613 | if (status < 0) | |
614 | goto done; | |
615 | ||
616 | /* No extra locking here; FLAG_SYSFS just signifies that the | |
617 | * request and export were done by on behalf of userspace, so | |
618 | * they may be undone on its behalf too. | |
619 | */ | |
620 | ||
621 | status = gpio_request(gpio, "sysfs"); | |
622 | if (status < 0) | |
623 | goto done; | |
624 | ||
625 | status = gpio_export(gpio, true); | |
626 | if (status < 0) | |
627 | gpio_free(gpio); | |
628 | else | |
629 | set_bit(FLAG_SYSFS, &gpio_desc[gpio].flags); | |
630 | ||
631 | done: | |
632 | if (status) | |
633 | pr_debug("%s: status %d\n", __func__, status); | |
634 | return status ? : len; | |
635 | } | |
636 | ||
28812fe1 AK |
637 | static ssize_t unexport_store(struct class *class, |
638 | struct class_attribute *attr, | |
639 | const char *buf, size_t len) | |
d8f388d8 DB |
640 | { |
641 | long gpio; | |
642 | int status; | |
643 | ||
644 | status = strict_strtol(buf, 0, &gpio); | |
645 | if (status < 0) | |
646 | goto done; | |
647 | ||
648 | status = -EINVAL; | |
649 | ||
650 | /* reject bogus commands (gpio_unexport ignores them) */ | |
651 | if (!gpio_is_valid(gpio)) | |
652 | goto done; | |
653 | ||
654 | /* No extra locking here; FLAG_SYSFS just signifies that the | |
655 | * request and export were done by on behalf of userspace, so | |
656 | * they may be undone on its behalf too. | |
657 | */ | |
658 | if (test_and_clear_bit(FLAG_SYSFS, &gpio_desc[gpio].flags)) { | |
659 | status = 0; | |
660 | gpio_free(gpio); | |
661 | } | |
662 | done: | |
663 | if (status) | |
664 | pr_debug("%s: status %d\n", __func__, status); | |
665 | return status ? : len; | |
666 | } | |
667 | ||
668 | static struct class_attribute gpio_class_attrs[] = { | |
669 | __ATTR(export, 0200, NULL, export_store), | |
670 | __ATTR(unexport, 0200, NULL, unexport_store), | |
671 | __ATTR_NULL, | |
672 | }; | |
673 | ||
674 | static struct class gpio_class = { | |
675 | .name = "gpio", | |
676 | .owner = THIS_MODULE, | |
677 | ||
678 | .class_attrs = gpio_class_attrs, | |
679 | }; | |
680 | ||
681 | ||
682 | /** | |
683 | * gpio_export - export a GPIO through sysfs | |
684 | * @gpio: gpio to make available, already requested | |
685 | * @direction_may_change: true if userspace may change gpio direction | |
686 | * Context: arch_initcall or later | |
687 | * | |
688 | * When drivers want to make a GPIO accessible to userspace after they | |
689 | * have requested it -- perhaps while debugging, or as part of their | |
690 | * public interface -- they may use this routine. If the GPIO can | |
691 | * change direction (some can't) and the caller allows it, userspace | |
692 | * will see "direction" sysfs attribute which may be used to change | |
693 | * the gpio's direction. A "value" attribute will always be provided. | |
694 | * | |
695 | * Returns zero on success, else an error. | |
696 | */ | |
697 | int gpio_export(unsigned gpio, bool direction_may_change) | |
698 | { | |
699 | unsigned long flags; | |
700 | struct gpio_desc *desc; | |
701 | int status = -EINVAL; | |
62154991 | 702 | const char *ioname = NULL; |
d8f388d8 DB |
703 | |
704 | /* can't export until sysfs is available ... */ | |
705 | if (!gpio_class.p) { | |
706 | pr_debug("%s: called too early!\n", __func__); | |
707 | return -ENOENT; | |
708 | } | |
709 | ||
710 | if (!gpio_is_valid(gpio)) | |
711 | goto done; | |
712 | ||
713 | mutex_lock(&sysfs_lock); | |
714 | ||
715 | spin_lock_irqsave(&gpio_lock, flags); | |
716 | desc = &gpio_desc[gpio]; | |
717 | if (test_bit(FLAG_REQUESTED, &desc->flags) | |
718 | && !test_bit(FLAG_EXPORT, &desc->flags)) { | |
719 | status = 0; | |
720 | if (!desc->chip->direction_input | |
721 | || !desc->chip->direction_output) | |
722 | direction_may_change = false; | |
723 | } | |
724 | spin_unlock_irqrestore(&gpio_lock, flags); | |
725 | ||
926b663c DS |
726 | if (desc->chip->names && desc->chip->names[gpio - desc->chip->base]) |
727 | ioname = desc->chip->names[gpio - desc->chip->base]; | |
728 | ||
d8f388d8 DB |
729 | if (status == 0) { |
730 | struct device *dev; | |
731 | ||
732 | dev = device_create(&gpio_class, desc->chip->dev, MKDEV(0, 0), | |
7cfe1395 | 733 | desc, ioname ? ioname : "gpio%u", gpio); |
d62668e1 | 734 | if (!IS_ERR(dev)) { |
07697461 | 735 | status = sysfs_create_group(&dev->kobj, |
d8f388d8 | 736 | &gpio_attr_group); |
07697461 JN |
737 | |
738 | if (!status && direction_may_change) | |
d8f388d8 | 739 | status = device_create_file(dev, |
07697461 | 740 | &dev_attr_direction); |
ff77c352 DG |
741 | |
742 | if (!status && gpio_to_irq(gpio) >= 0 | |
743 | && (direction_may_change | |
744 | || !test_bit(FLAG_IS_OUT, | |
745 | &desc->flags))) | |
746 | status = device_create_file(dev, | |
747 | &dev_attr_edge); | |
748 | ||
d8f388d8 DB |
749 | if (status != 0) |
750 | device_unregister(dev); | |
751 | } else | |
d62668e1 | 752 | status = PTR_ERR(dev); |
d8f388d8 DB |
753 | if (status == 0) |
754 | set_bit(FLAG_EXPORT, &desc->flags); | |
755 | } | |
756 | ||
757 | mutex_unlock(&sysfs_lock); | |
758 | ||
759 | done: | |
760 | if (status) | |
761 | pr_debug("%s: gpio%d status %d\n", __func__, gpio, status); | |
762 | ||
763 | return status; | |
764 | } | |
765 | EXPORT_SYMBOL_GPL(gpio_export); | |
766 | ||
767 | static int match_export(struct device *dev, void *data) | |
768 | { | |
769 | return dev_get_drvdata(dev) == data; | |
770 | } | |
771 | ||
a4177ee7 JN |
772 | /** |
773 | * gpio_export_link - create a sysfs link to an exported GPIO node | |
774 | * @dev: device under which to create symlink | |
775 | * @name: name of the symlink | |
776 | * @gpio: gpio to create symlink to, already exported | |
777 | * | |
778 | * Set up a symlink from /sys/.../dev/name to /sys/class/gpio/gpioN | |
779 | * node. Caller is responsible for unlinking. | |
780 | * | |
781 | * Returns zero on success, else an error. | |
782 | */ | |
783 | int gpio_export_link(struct device *dev, const char *name, unsigned gpio) | |
784 | { | |
785 | struct gpio_desc *desc; | |
786 | int status = -EINVAL; | |
787 | ||
788 | if (!gpio_is_valid(gpio)) | |
789 | goto done; | |
790 | ||
791 | mutex_lock(&sysfs_lock); | |
792 | ||
793 | desc = &gpio_desc[gpio]; | |
794 | ||
795 | if (test_bit(FLAG_EXPORT, &desc->flags)) { | |
796 | struct device *tdev; | |
797 | ||
798 | tdev = class_find_device(&gpio_class, NULL, desc, match_export); | |
799 | if (tdev != NULL) { | |
800 | status = sysfs_create_link(&dev->kobj, &tdev->kobj, | |
801 | name); | |
802 | } else { | |
803 | status = -ENODEV; | |
804 | } | |
805 | } | |
806 | ||
807 | mutex_unlock(&sysfs_lock); | |
808 | ||
809 | done: | |
810 | if (status) | |
811 | pr_debug("%s: gpio%d status %d\n", __func__, gpio, status); | |
812 | ||
813 | return status; | |
814 | } | |
815 | EXPORT_SYMBOL_GPL(gpio_export_link); | |
816 | ||
07697461 JN |
817 | |
818 | /** | |
819 | * gpio_sysfs_set_active_low - set the polarity of gpio sysfs value | |
820 | * @gpio: gpio to change | |
821 | * @value: non-zero to use active low, i.e. inverted values | |
822 | * | |
823 | * Set the polarity of /sys/class/gpio/gpioN/value sysfs attribute. | |
824 | * The GPIO does not have to be exported yet. If poll(2) support has | |
825 | * been enabled for either rising or falling edge, it will be | |
826 | * reconfigured to follow the new polarity. | |
827 | * | |
828 | * Returns zero on success, else an error. | |
829 | */ | |
830 | int gpio_sysfs_set_active_low(unsigned gpio, int value) | |
831 | { | |
832 | struct gpio_desc *desc; | |
833 | struct device *dev = NULL; | |
834 | int status = -EINVAL; | |
835 | ||
836 | if (!gpio_is_valid(gpio)) | |
837 | goto done; | |
838 | ||
839 | mutex_lock(&sysfs_lock); | |
840 | ||
841 | desc = &gpio_desc[gpio]; | |
842 | ||
843 | if (test_bit(FLAG_EXPORT, &desc->flags)) { | |
07697461 JN |
844 | dev = class_find_device(&gpio_class, NULL, desc, match_export); |
845 | if (dev == NULL) { | |
846 | status = -ENODEV; | |
847 | goto unlock; | |
848 | } | |
849 | } | |
850 | ||
851 | status = sysfs_set_active_low(desc, dev, value); | |
852 | ||
853 | unlock: | |
854 | mutex_unlock(&sysfs_lock); | |
855 | ||
856 | done: | |
857 | if (status) | |
858 | pr_debug("%s: gpio%d status %d\n", __func__, gpio, status); | |
859 | ||
860 | return status; | |
861 | } | |
862 | EXPORT_SYMBOL_GPL(gpio_sysfs_set_active_low); | |
863 | ||
d8f388d8 DB |
864 | /** |
865 | * gpio_unexport - reverse effect of gpio_export() | |
866 | * @gpio: gpio to make unavailable | |
867 | * | |
868 | * This is implicit on gpio_free(). | |
869 | */ | |
870 | void gpio_unexport(unsigned gpio) | |
871 | { | |
872 | struct gpio_desc *desc; | |
6a99ad4a | 873 | int status = 0; |
d8f388d8 | 874 | |
6a99ad4a JP |
875 | if (!gpio_is_valid(gpio)) { |
876 | status = -EINVAL; | |
d8f388d8 | 877 | goto done; |
6a99ad4a | 878 | } |
d8f388d8 DB |
879 | |
880 | mutex_lock(&sysfs_lock); | |
881 | ||
882 | desc = &gpio_desc[gpio]; | |
926b663c | 883 | |
d8f388d8 DB |
884 | if (test_bit(FLAG_EXPORT, &desc->flags)) { |
885 | struct device *dev = NULL; | |
886 | ||
887 | dev = class_find_device(&gpio_class, NULL, desc, match_export); | |
888 | if (dev) { | |
ff77c352 | 889 | gpio_setup_irq(desc, dev, 0); |
d8f388d8 DB |
890 | clear_bit(FLAG_EXPORT, &desc->flags); |
891 | put_device(dev); | |
892 | device_unregister(dev); | |
d8f388d8 DB |
893 | } else |
894 | status = -ENODEV; | |
895 | } | |
896 | ||
897 | mutex_unlock(&sysfs_lock); | |
898 | done: | |
899 | if (status) | |
900 | pr_debug("%s: gpio%d status %d\n", __func__, gpio, status); | |
901 | } | |
902 | EXPORT_SYMBOL_GPL(gpio_unexport); | |
903 | ||
904 | static int gpiochip_export(struct gpio_chip *chip) | |
905 | { | |
906 | int status; | |
907 | struct device *dev; | |
908 | ||
909 | /* Many systems register gpio chips for SOC support very early, | |
910 | * before driver model support is available. In those cases we | |
911 | * export this later, in gpiolib_sysfs_init() ... here we just | |
912 | * verify that _some_ field of gpio_class got initialized. | |
913 | */ | |
914 | if (!gpio_class.p) | |
915 | return 0; | |
916 | ||
917 | /* use chip->base for the ID; it's already known to be unique */ | |
918 | mutex_lock(&sysfs_lock); | |
919 | dev = device_create(&gpio_class, chip->dev, MKDEV(0, 0), chip, | |
920 | "gpiochip%d", chip->base); | |
d62668e1 | 921 | if (!IS_ERR(dev)) { |
d8f388d8 DB |
922 | status = sysfs_create_group(&dev->kobj, |
923 | &gpiochip_attr_group); | |
924 | } else | |
d62668e1 | 925 | status = PTR_ERR(dev); |
d8f388d8 DB |
926 | chip->exported = (status == 0); |
927 | mutex_unlock(&sysfs_lock); | |
928 | ||
929 | if (status) { | |
930 | unsigned long flags; | |
931 | unsigned gpio; | |
932 | ||
933 | spin_lock_irqsave(&gpio_lock, flags); | |
934 | gpio = chip->base; | |
935 | while (gpio_desc[gpio].chip == chip) | |
936 | gpio_desc[gpio++].chip = NULL; | |
937 | spin_unlock_irqrestore(&gpio_lock, flags); | |
938 | ||
939 | pr_debug("%s: chip %s status %d\n", __func__, | |
940 | chip->label, status); | |
941 | } | |
942 | ||
943 | return status; | |
944 | } | |
945 | ||
946 | static void gpiochip_unexport(struct gpio_chip *chip) | |
947 | { | |
948 | int status; | |
949 | struct device *dev; | |
950 | ||
951 | mutex_lock(&sysfs_lock); | |
952 | dev = class_find_device(&gpio_class, NULL, chip, match_export); | |
953 | if (dev) { | |
954 | put_device(dev); | |
955 | device_unregister(dev); | |
956 | chip->exported = 0; | |
957 | status = 0; | |
958 | } else | |
959 | status = -ENODEV; | |
960 | mutex_unlock(&sysfs_lock); | |
961 | ||
962 | if (status) | |
963 | pr_debug("%s: chip %s status %d\n", __func__, | |
964 | chip->label, status); | |
965 | } | |
966 | ||
967 | static int __init gpiolib_sysfs_init(void) | |
968 | { | |
969 | int status; | |
970 | unsigned long flags; | |
971 | unsigned gpio; | |
972 | ||
973 | status = class_register(&gpio_class); | |
974 | if (status < 0) | |
975 | return status; | |
976 | ||
977 | /* Scan and register the gpio_chips which registered very | |
978 | * early (e.g. before the class_register above was called). | |
979 | * | |
980 | * We run before arch_initcall() so chip->dev nodes can have | |
981 | * registered, and so arch_initcall() can always gpio_export(). | |
982 | */ | |
983 | spin_lock_irqsave(&gpio_lock, flags); | |
984 | for (gpio = 0; gpio < ARCH_NR_GPIOS; gpio++) { | |
985 | struct gpio_chip *chip; | |
986 | ||
987 | chip = gpio_desc[gpio].chip; | |
988 | if (!chip || chip->exported) | |
989 | continue; | |
990 | ||
991 | spin_unlock_irqrestore(&gpio_lock, flags); | |
992 | status = gpiochip_export(chip); | |
993 | spin_lock_irqsave(&gpio_lock, flags); | |
994 | } | |
995 | spin_unlock_irqrestore(&gpio_lock, flags); | |
996 | ||
997 | ||
998 | return status; | |
999 | } | |
1000 | postcore_initcall(gpiolib_sysfs_init); | |
1001 | ||
1002 | #else | |
1003 | static inline int gpiochip_export(struct gpio_chip *chip) | |
1004 | { | |
1005 | return 0; | |
1006 | } | |
1007 | ||
1008 | static inline void gpiochip_unexport(struct gpio_chip *chip) | |
1009 | { | |
1010 | } | |
1011 | ||
1012 | #endif /* CONFIG_GPIO_SYSFS */ | |
1013 | ||
d2876d08 DB |
1014 | /** |
1015 | * gpiochip_add() - register a gpio_chip | |
1016 | * @chip: the chip to register, with chip->base initialized | |
1017 | * Context: potentially before irqs or kmalloc will work | |
1018 | * | |
1019 | * Returns a negative errno if the chip can't be registered, such as | |
1020 | * because the chip->base is invalid or already associated with a | |
1021 | * different chip. Otherwise it returns zero as a success code. | |
8d0aab2f | 1022 | * |
d8f388d8 DB |
1023 | * When gpiochip_add() is called very early during boot, so that GPIOs |
1024 | * can be freely used, the chip->dev device must be registered before | |
1025 | * the gpio framework's arch_initcall(). Otherwise sysfs initialization | |
1026 | * for GPIOs will fail rudely. | |
1027 | * | |
8d0aab2f AV |
1028 | * If chip->base is negative, this requests dynamic assignment of |
1029 | * a range of valid GPIOs. | |
d2876d08 DB |
1030 | */ |
1031 | int gpiochip_add(struct gpio_chip *chip) | |
1032 | { | |
1033 | unsigned long flags; | |
1034 | int status = 0; | |
1035 | unsigned id; | |
8d0aab2f | 1036 | int base = chip->base; |
d2876d08 | 1037 | |
bff5fda9 | 1038 | if ((!gpio_is_valid(base) || !gpio_is_valid(base + chip->ngpio - 1)) |
8d0aab2f | 1039 | && base >= 0) { |
d2876d08 DB |
1040 | status = -EINVAL; |
1041 | goto fail; | |
1042 | } | |
1043 | ||
1044 | spin_lock_irqsave(&gpio_lock, flags); | |
1045 | ||
8d0aab2f AV |
1046 | if (base < 0) { |
1047 | base = gpiochip_find_base(chip->ngpio); | |
1048 | if (base < 0) { | |
1049 | status = base; | |
d8f388d8 | 1050 | goto unlock; |
8d0aab2f AV |
1051 | } |
1052 | chip->base = base; | |
1053 | } | |
1054 | ||
d2876d08 | 1055 | /* these GPIO numbers must not be managed by another gpio_chip */ |
8d0aab2f | 1056 | for (id = base; id < base + chip->ngpio; id++) { |
d2876d08 DB |
1057 | if (gpio_desc[id].chip != NULL) { |
1058 | status = -EBUSY; | |
1059 | break; | |
1060 | } | |
1061 | } | |
1062 | if (status == 0) { | |
8d0aab2f | 1063 | for (id = base; id < base + chip->ngpio; id++) { |
d2876d08 | 1064 | gpio_desc[id].chip = chip; |
d8f388d8 DB |
1065 | |
1066 | /* REVISIT: most hardware initializes GPIOs as | |
1067 | * inputs (often with pullups enabled) so power | |
1068 | * usage is minimized. Linux code should set the | |
1069 | * gpio direction first thing; but until it does, | |
1070 | * we may expose the wrong direction in sysfs. | |
1071 | */ | |
1072 | gpio_desc[id].flags = !chip->direction_input | |
1073 | ? (1 << FLAG_IS_OUT) | |
1074 | : 0; | |
d2876d08 DB |
1075 | } |
1076 | } | |
1077 | ||
391c970c AV |
1078 | of_gpiochip_add(chip); |
1079 | ||
d8f388d8 | 1080 | unlock: |
d2876d08 | 1081 | spin_unlock_irqrestore(&gpio_lock, flags); |
cedb1881 AV |
1082 | |
1083 | if (status) | |
1084 | goto fail; | |
1085 | ||
1086 | status = gpiochip_export(chip); | |
1087 | if (status) | |
1088 | goto fail; | |
1089 | ||
1090 | return 0; | |
d2876d08 DB |
1091 | fail: |
1092 | /* failures here can mean systems won't boot... */ | |
cedb1881 AV |
1093 | pr_err("gpiochip_add: gpios %d..%d (%s) failed to register\n", |
1094 | chip->base, chip->base + chip->ngpio - 1, | |
1095 | chip->label ? : "generic"); | |
d2876d08 DB |
1096 | return status; |
1097 | } | |
1098 | EXPORT_SYMBOL_GPL(gpiochip_add); | |
1099 | ||
1100 | /** | |
1101 | * gpiochip_remove() - unregister a gpio_chip | |
1102 | * @chip: the chip to unregister | |
1103 | * | |
1104 | * A gpio_chip with any GPIOs still requested may not be removed. | |
1105 | */ | |
1106 | int gpiochip_remove(struct gpio_chip *chip) | |
1107 | { | |
1108 | unsigned long flags; | |
1109 | int status = 0; | |
1110 | unsigned id; | |
1111 | ||
1112 | spin_lock_irqsave(&gpio_lock, flags); | |
1113 | ||
391c970c AV |
1114 | of_gpiochip_remove(chip); |
1115 | ||
d2876d08 DB |
1116 | for (id = chip->base; id < chip->base + chip->ngpio; id++) { |
1117 | if (test_bit(FLAG_REQUESTED, &gpio_desc[id].flags)) { | |
1118 | status = -EBUSY; | |
1119 | break; | |
1120 | } | |
1121 | } | |
1122 | if (status == 0) { | |
1123 | for (id = chip->base; id < chip->base + chip->ngpio; id++) | |
1124 | gpio_desc[id].chip = NULL; | |
1125 | } | |
1126 | ||
1127 | spin_unlock_irqrestore(&gpio_lock, flags); | |
d8f388d8 DB |
1128 | |
1129 | if (status == 0) | |
1130 | gpiochip_unexport(chip); | |
1131 | ||
d2876d08 DB |
1132 | return status; |
1133 | } | |
1134 | EXPORT_SYMBOL_GPL(gpiochip_remove); | |
1135 | ||
594fa265 GL |
1136 | /** |
1137 | * gpiochip_find() - iterator for locating a specific gpio_chip | |
1138 | * @data: data to pass to match function | |
1139 | * @callback: Callback function to check gpio_chip | |
1140 | * | |
1141 | * Similar to bus_find_device. It returns a reference to a gpio_chip as | |
1142 | * determined by a user supplied @match callback. The callback should return | |
1143 | * 0 if the device doesn't match and non-zero if it does. If the callback is | |
1144 | * non-zero, this function will return to the caller and not iterate over any | |
1145 | * more gpio_chips. | |
1146 | */ | |
1147 | struct gpio_chip *gpiochip_find(void *data, | |
1148 | int (*match)(struct gpio_chip *chip, void *data)) | |
1149 | { | |
1150 | struct gpio_chip *chip = NULL; | |
1151 | unsigned long flags; | |
1152 | int i; | |
1153 | ||
1154 | spin_lock_irqsave(&gpio_lock, flags); | |
1155 | for (i = 0; i < ARCH_NR_GPIOS; i++) { | |
1156 | if (!gpio_desc[i].chip) | |
1157 | continue; | |
1158 | ||
1159 | if (match(gpio_desc[i].chip, data)) { | |
1160 | chip = gpio_desc[i].chip; | |
1161 | break; | |
1162 | } | |
1163 | } | |
1164 | spin_unlock_irqrestore(&gpio_lock, flags); | |
1165 | ||
1166 | return chip; | |
1167 | } | |
d2876d08 DB |
1168 | |
1169 | /* These "optional" allocation calls help prevent drivers from stomping | |
1170 | * on each other, and help provide better diagnostics in debugfs. | |
1171 | * They're called even less than the "set direction" calls. | |
1172 | */ | |
1173 | int gpio_request(unsigned gpio, const char *label) | |
1174 | { | |
1175 | struct gpio_desc *desc; | |
35e8bb51 | 1176 | struct gpio_chip *chip; |
d2876d08 DB |
1177 | int status = -EINVAL; |
1178 | unsigned long flags; | |
1179 | ||
1180 | spin_lock_irqsave(&gpio_lock, flags); | |
1181 | ||
e6de1808 | 1182 | if (!gpio_is_valid(gpio)) |
d2876d08 DB |
1183 | goto done; |
1184 | desc = &gpio_desc[gpio]; | |
35e8bb51 DB |
1185 | chip = desc->chip; |
1186 | if (chip == NULL) | |
d2876d08 DB |
1187 | goto done; |
1188 | ||
35e8bb51 | 1189 | if (!try_module_get(chip->owner)) |
438d8908 GL |
1190 | goto done; |
1191 | ||
d2876d08 | 1192 | /* NOTE: gpio_request() can be called in early boot, |
35e8bb51 | 1193 | * before IRQs are enabled, for non-sleeping (SOC) GPIOs. |
d2876d08 DB |
1194 | */ |
1195 | ||
1196 | if (test_and_set_bit(FLAG_REQUESTED, &desc->flags) == 0) { | |
1197 | desc_set_label(desc, label ? : "?"); | |
1198 | status = 0; | |
438d8908 | 1199 | } else { |
d2876d08 | 1200 | status = -EBUSY; |
35e8bb51 | 1201 | module_put(chip->owner); |
7460db56 | 1202 | goto done; |
35e8bb51 DB |
1203 | } |
1204 | ||
1205 | if (chip->request) { | |
1206 | /* chip->request may sleep */ | |
1207 | spin_unlock_irqrestore(&gpio_lock, flags); | |
1208 | status = chip->request(chip, gpio - chip->base); | |
1209 | spin_lock_irqsave(&gpio_lock, flags); | |
1210 | ||
1211 | if (status < 0) { | |
1212 | desc_set_label(desc, NULL); | |
1213 | module_put(chip->owner); | |
1214 | clear_bit(FLAG_REQUESTED, &desc->flags); | |
1215 | } | |
438d8908 | 1216 | } |
d2876d08 DB |
1217 | |
1218 | done: | |
1219 | if (status) | |
1220 | pr_debug("gpio_request: gpio-%d (%s) status %d\n", | |
1221 | gpio, label ? : "?", status); | |
1222 | spin_unlock_irqrestore(&gpio_lock, flags); | |
1223 | return status; | |
1224 | } | |
1225 | EXPORT_SYMBOL_GPL(gpio_request); | |
1226 | ||
1227 | void gpio_free(unsigned gpio) | |
1228 | { | |
1229 | unsigned long flags; | |
1230 | struct gpio_desc *desc; | |
35e8bb51 | 1231 | struct gpio_chip *chip; |
d2876d08 | 1232 | |
3d599d1c UKK |
1233 | might_sleep(); |
1234 | ||
e6de1808 | 1235 | if (!gpio_is_valid(gpio)) { |
d2876d08 DB |
1236 | WARN_ON(extra_checks); |
1237 | return; | |
1238 | } | |
1239 | ||
d8f388d8 DB |
1240 | gpio_unexport(gpio); |
1241 | ||
d2876d08 DB |
1242 | spin_lock_irqsave(&gpio_lock, flags); |
1243 | ||
1244 | desc = &gpio_desc[gpio]; | |
35e8bb51 DB |
1245 | chip = desc->chip; |
1246 | if (chip && test_bit(FLAG_REQUESTED, &desc->flags)) { | |
1247 | if (chip->free) { | |
1248 | spin_unlock_irqrestore(&gpio_lock, flags); | |
9c4ba946 | 1249 | might_sleep_if(chip->can_sleep); |
35e8bb51 DB |
1250 | chip->free(chip, gpio - chip->base); |
1251 | spin_lock_irqsave(&gpio_lock, flags); | |
1252 | } | |
d2876d08 | 1253 | desc_set_label(desc, NULL); |
438d8908 | 1254 | module_put(desc->chip->owner); |
07697461 | 1255 | clear_bit(FLAG_ACTIVE_LOW, &desc->flags); |
35e8bb51 | 1256 | clear_bit(FLAG_REQUESTED, &desc->flags); |
438d8908 | 1257 | } else |
d2876d08 DB |
1258 | WARN_ON(extra_checks); |
1259 | ||
1260 | spin_unlock_irqrestore(&gpio_lock, flags); | |
1261 | } | |
1262 | EXPORT_SYMBOL_GPL(gpio_free); | |
1263 | ||
3e45f1d1 EM |
1264 | /** |
1265 | * gpio_request_one - request a single GPIO with initial configuration | |
1266 | * @gpio: the GPIO number | |
1267 | * @flags: GPIO configuration as specified by GPIOF_* | |
1268 | * @label: a literal description string of this GPIO | |
1269 | */ | |
1270 | int gpio_request_one(unsigned gpio, unsigned long flags, const char *label) | |
1271 | { | |
1272 | int err; | |
1273 | ||
1274 | err = gpio_request(gpio, label); | |
1275 | if (err) | |
1276 | return err; | |
1277 | ||
1278 | if (flags & GPIOF_DIR_IN) | |
1279 | err = gpio_direction_input(gpio); | |
1280 | else | |
1281 | err = gpio_direction_output(gpio, | |
1282 | (flags & GPIOF_INIT_HIGH) ? 1 : 0); | |
1283 | ||
e254811c AK |
1284 | if (err) |
1285 | gpio_free(gpio); | |
1286 | ||
3e45f1d1 EM |
1287 | return err; |
1288 | } | |
1289 | EXPORT_SYMBOL_GPL(gpio_request_one); | |
1290 | ||
1291 | /** | |
1292 | * gpio_request_array - request multiple GPIOs in a single call | |
1293 | * @array: array of the 'struct gpio' | |
1294 | * @num: how many GPIOs in the array | |
1295 | */ | |
1296 | int gpio_request_array(struct gpio *array, size_t num) | |
1297 | { | |
1298 | int i, err; | |
1299 | ||
1300 | for (i = 0; i < num; i++, array++) { | |
1301 | err = gpio_request_one(array->gpio, array->flags, array->label); | |
1302 | if (err) | |
1303 | goto err_free; | |
1304 | } | |
1305 | return 0; | |
1306 | ||
1307 | err_free: | |
1308 | while (i--) | |
1309 | gpio_free((--array)->gpio); | |
1310 | return err; | |
1311 | } | |
1312 | EXPORT_SYMBOL_GPL(gpio_request_array); | |
1313 | ||
1314 | /** | |
1315 | * gpio_free_array - release multiple GPIOs in a single call | |
1316 | * @array: array of the 'struct gpio' | |
1317 | * @num: how many GPIOs in the array | |
1318 | */ | |
1319 | void gpio_free_array(struct gpio *array, size_t num) | |
1320 | { | |
1321 | while (num--) | |
1322 | gpio_free((array++)->gpio); | |
1323 | } | |
1324 | EXPORT_SYMBOL_GPL(gpio_free_array); | |
d2876d08 DB |
1325 | |
1326 | /** | |
1327 | * gpiochip_is_requested - return string iff signal was requested | |
1328 | * @chip: controller managing the signal | |
1329 | * @offset: of signal within controller's 0..(ngpio - 1) range | |
1330 | * | |
1331 | * Returns NULL if the GPIO is not currently requested, else a string. | |
1332 | * If debugfs support is enabled, the string returned is the label passed | |
1333 | * to gpio_request(); otherwise it is a meaningless constant. | |
1334 | * | |
1335 | * This function is for use by GPIO controller drivers. The label can | |
1336 | * help with diagnostics, and knowing that the signal is used as a GPIO | |
1337 | * can help avoid accidentally multiplexing it to another controller. | |
1338 | */ | |
1339 | const char *gpiochip_is_requested(struct gpio_chip *chip, unsigned offset) | |
1340 | { | |
1341 | unsigned gpio = chip->base + offset; | |
1342 | ||
e6de1808 | 1343 | if (!gpio_is_valid(gpio) || gpio_desc[gpio].chip != chip) |
d2876d08 DB |
1344 | return NULL; |
1345 | if (test_bit(FLAG_REQUESTED, &gpio_desc[gpio].flags) == 0) | |
1346 | return NULL; | |
1347 | #ifdef CONFIG_DEBUG_FS | |
1348 | return gpio_desc[gpio].label; | |
1349 | #else | |
1350 | return "?"; | |
1351 | #endif | |
1352 | } | |
1353 | EXPORT_SYMBOL_GPL(gpiochip_is_requested); | |
1354 | ||
1355 | ||
1356 | /* Drivers MUST set GPIO direction before making get/set calls. In | |
1357 | * some cases this is done in early boot, before IRQs are enabled. | |
1358 | * | |
1359 | * As a rule these aren't called more than once (except for drivers | |
1360 | * using the open-drain emulation idiom) so these are natural places | |
1361 | * to accumulate extra debugging checks. Note that we can't (yet) | |
1362 | * rely on gpio_request() having been called beforehand. | |
1363 | */ | |
1364 | ||
1365 | int gpio_direction_input(unsigned gpio) | |
1366 | { | |
1367 | unsigned long flags; | |
1368 | struct gpio_chip *chip; | |
1369 | struct gpio_desc *desc = &gpio_desc[gpio]; | |
1370 | int status = -EINVAL; | |
1371 | ||
1372 | spin_lock_irqsave(&gpio_lock, flags); | |
1373 | ||
e6de1808 | 1374 | if (!gpio_is_valid(gpio)) |
d2876d08 DB |
1375 | goto fail; |
1376 | chip = desc->chip; | |
1377 | if (!chip || !chip->get || !chip->direction_input) | |
1378 | goto fail; | |
1379 | gpio -= chip->base; | |
1380 | if (gpio >= chip->ngpio) | |
1381 | goto fail; | |
35e8bb51 DB |
1382 | status = gpio_ensure_requested(desc, gpio); |
1383 | if (status < 0) | |
1384 | goto fail; | |
d2876d08 DB |
1385 | |
1386 | /* now we know the gpio is valid and chip won't vanish */ | |
1387 | ||
1388 | spin_unlock_irqrestore(&gpio_lock, flags); | |
1389 | ||
9c4ba946 | 1390 | might_sleep_if(chip->can_sleep); |
d2876d08 | 1391 | |
35e8bb51 DB |
1392 | if (status) { |
1393 | status = chip->request(chip, gpio); | |
1394 | if (status < 0) { | |
1395 | pr_debug("GPIO-%d: chip request fail, %d\n", | |
1396 | chip->base + gpio, status); | |
1397 | /* and it's not available to anyone else ... | |
1398 | * gpio_request() is the fully clean solution. | |
1399 | */ | |
1400 | goto lose; | |
1401 | } | |
1402 | } | |
1403 | ||
d2876d08 DB |
1404 | status = chip->direction_input(chip, gpio); |
1405 | if (status == 0) | |
1406 | clear_bit(FLAG_IS_OUT, &desc->flags); | |
35e8bb51 | 1407 | lose: |
d2876d08 DB |
1408 | return status; |
1409 | fail: | |
1410 | spin_unlock_irqrestore(&gpio_lock, flags); | |
1411 | if (status) | |
1412 | pr_debug("%s: gpio-%d status %d\n", | |
145980a0 | 1413 | __func__, gpio, status); |
d2876d08 DB |
1414 | return status; |
1415 | } | |
1416 | EXPORT_SYMBOL_GPL(gpio_direction_input); | |
1417 | ||
1418 | int gpio_direction_output(unsigned gpio, int value) | |
1419 | { | |
1420 | unsigned long flags; | |
1421 | struct gpio_chip *chip; | |
1422 | struct gpio_desc *desc = &gpio_desc[gpio]; | |
1423 | int status = -EINVAL; | |
1424 | ||
1425 | spin_lock_irqsave(&gpio_lock, flags); | |
1426 | ||
e6de1808 | 1427 | if (!gpio_is_valid(gpio)) |
d2876d08 DB |
1428 | goto fail; |
1429 | chip = desc->chip; | |
1430 | if (!chip || !chip->set || !chip->direction_output) | |
1431 | goto fail; | |
1432 | gpio -= chip->base; | |
1433 | if (gpio >= chip->ngpio) | |
1434 | goto fail; | |
35e8bb51 DB |
1435 | status = gpio_ensure_requested(desc, gpio); |
1436 | if (status < 0) | |
1437 | goto fail; | |
d2876d08 DB |
1438 | |
1439 | /* now we know the gpio is valid and chip won't vanish */ | |
1440 | ||
1441 | spin_unlock_irqrestore(&gpio_lock, flags); | |
1442 | ||
9c4ba946 | 1443 | might_sleep_if(chip->can_sleep); |
d2876d08 | 1444 | |
35e8bb51 DB |
1445 | if (status) { |
1446 | status = chip->request(chip, gpio); | |
1447 | if (status < 0) { | |
1448 | pr_debug("GPIO-%d: chip request fail, %d\n", | |
1449 | chip->base + gpio, status); | |
1450 | /* and it's not available to anyone else ... | |
1451 | * gpio_request() is the fully clean solution. | |
1452 | */ | |
1453 | goto lose; | |
1454 | } | |
1455 | } | |
1456 | ||
d2876d08 DB |
1457 | status = chip->direction_output(chip, gpio, value); |
1458 | if (status == 0) | |
1459 | set_bit(FLAG_IS_OUT, &desc->flags); | |
35e8bb51 | 1460 | lose: |
d2876d08 DB |
1461 | return status; |
1462 | fail: | |
1463 | spin_unlock_irqrestore(&gpio_lock, flags); | |
1464 | if (status) | |
1465 | pr_debug("%s: gpio-%d status %d\n", | |
145980a0 | 1466 | __func__, gpio, status); |
d2876d08 DB |
1467 | return status; |
1468 | } | |
1469 | EXPORT_SYMBOL_GPL(gpio_direction_output); | |
1470 | ||
c4b5be98 FB |
1471 | /** |
1472 | * gpio_set_debounce - sets @debounce time for a @gpio | |
1473 | * @gpio: the gpio to set debounce time | |
1474 | * @debounce: debounce time is microseconds | |
1475 | */ | |
1476 | int gpio_set_debounce(unsigned gpio, unsigned debounce) | |
1477 | { | |
1478 | unsigned long flags; | |
1479 | struct gpio_chip *chip; | |
1480 | struct gpio_desc *desc = &gpio_desc[gpio]; | |
1481 | int status = -EINVAL; | |
1482 | ||
1483 | spin_lock_irqsave(&gpio_lock, flags); | |
1484 | ||
1485 | if (!gpio_is_valid(gpio)) | |
1486 | goto fail; | |
1487 | chip = desc->chip; | |
1488 | if (!chip || !chip->set || !chip->set_debounce) | |
1489 | goto fail; | |
1490 | gpio -= chip->base; | |
1491 | if (gpio >= chip->ngpio) | |
1492 | goto fail; | |
1493 | status = gpio_ensure_requested(desc, gpio); | |
1494 | if (status < 0) | |
1495 | goto fail; | |
1496 | ||
1497 | /* now we know the gpio is valid and chip won't vanish */ | |
1498 | ||
1499 | spin_unlock_irqrestore(&gpio_lock, flags); | |
1500 | ||
9c4ba946 | 1501 | might_sleep_if(chip->can_sleep); |
c4b5be98 FB |
1502 | |
1503 | return chip->set_debounce(chip, gpio, debounce); | |
1504 | ||
1505 | fail: | |
1506 | spin_unlock_irqrestore(&gpio_lock, flags); | |
1507 | if (status) | |
1508 | pr_debug("%s: gpio-%d status %d\n", | |
1509 | __func__, gpio, status); | |
1510 | ||
1511 | return status; | |
1512 | } | |
1513 | EXPORT_SYMBOL_GPL(gpio_set_debounce); | |
d2876d08 DB |
1514 | |
1515 | /* I/O calls are only valid after configuration completed; the relevant | |
1516 | * "is this a valid GPIO" error checks should already have been done. | |
1517 | * | |
1518 | * "Get" operations are often inlinable as reading a pin value register, | |
1519 | * and masking the relevant bit in that register. | |
1520 | * | |
1521 | * When "set" operations are inlinable, they involve writing that mask to | |
1522 | * one register to set a low value, or a different register to set it high. | |
1523 | * Otherwise locking is needed, so there may be little value to inlining. | |
1524 | * | |
1525 | *------------------------------------------------------------------------ | |
1526 | * | |
1527 | * IMPORTANT!!! The hot paths -- get/set value -- assume that callers | |
1528 | * have requested the GPIO. That can include implicit requesting by | |
1529 | * a direction setting call. Marking a gpio as requested locks its chip | |
1530 | * in memory, guaranteeing that these table lookups need no more locking | |
1531 | * and that gpiochip_remove() will fail. | |
1532 | * | |
1533 | * REVISIT when debugging, consider adding some instrumentation to ensure | |
1534 | * that the GPIO was actually requested. | |
1535 | */ | |
1536 | ||
1537 | /** | |
1538 | * __gpio_get_value() - return a gpio's value | |
1539 | * @gpio: gpio whose value will be returned | |
1540 | * Context: any | |
1541 | * | |
1542 | * This is used directly or indirectly to implement gpio_get_value(). | |
1543 | * It returns the zero or nonzero value provided by the associated | |
1544 | * gpio_chip.get() method; or zero if no such method is provided. | |
1545 | */ | |
1546 | int __gpio_get_value(unsigned gpio) | |
1547 | { | |
1548 | struct gpio_chip *chip; | |
1549 | ||
1550 | chip = gpio_to_chip(gpio); | |
9c4ba946 | 1551 | WARN_ON(chip->can_sleep); |
d2876d08 DB |
1552 | return chip->get ? chip->get(chip, gpio - chip->base) : 0; |
1553 | } | |
1554 | EXPORT_SYMBOL_GPL(__gpio_get_value); | |
1555 | ||
1556 | /** | |
1557 | * __gpio_set_value() - assign a gpio's value | |
1558 | * @gpio: gpio whose value will be assigned | |
1559 | * @value: value to assign | |
1560 | * Context: any | |
1561 | * | |
1562 | * This is used directly or indirectly to implement gpio_set_value(). | |
1563 | * It invokes the associated gpio_chip.set() method. | |
1564 | */ | |
1565 | void __gpio_set_value(unsigned gpio, int value) | |
1566 | { | |
1567 | struct gpio_chip *chip; | |
1568 | ||
1569 | chip = gpio_to_chip(gpio); | |
9c4ba946 | 1570 | WARN_ON(chip->can_sleep); |
d2876d08 DB |
1571 | chip->set(chip, gpio - chip->base, value); |
1572 | } | |
1573 | EXPORT_SYMBOL_GPL(__gpio_set_value); | |
1574 | ||
1575 | /** | |
1576 | * __gpio_cansleep() - report whether gpio value access will sleep | |
1577 | * @gpio: gpio in question | |
1578 | * Context: any | |
1579 | * | |
1580 | * This is used directly or indirectly to implement gpio_cansleep(). It | |
1581 | * returns nonzero if access reading or writing the GPIO value can sleep. | |
1582 | */ | |
1583 | int __gpio_cansleep(unsigned gpio) | |
1584 | { | |
1585 | struct gpio_chip *chip; | |
1586 | ||
1587 | /* only call this on GPIOs that are valid! */ | |
1588 | chip = gpio_to_chip(gpio); | |
1589 | ||
1590 | return chip->can_sleep; | |
1591 | } | |
1592 | EXPORT_SYMBOL_GPL(__gpio_cansleep); | |
1593 | ||
0f6d504e DB |
1594 | /** |
1595 | * __gpio_to_irq() - return the IRQ corresponding to a GPIO | |
1596 | * @gpio: gpio whose IRQ will be returned (already requested) | |
1597 | * Context: any | |
1598 | * | |
1599 | * This is used directly or indirectly to implement gpio_to_irq(). | |
1600 | * It returns the number of the IRQ signaled by this (input) GPIO, | |
1601 | * or a negative errno. | |
1602 | */ | |
1603 | int __gpio_to_irq(unsigned gpio) | |
1604 | { | |
1605 | struct gpio_chip *chip; | |
1606 | ||
1607 | chip = gpio_to_chip(gpio); | |
1608 | return chip->to_irq ? chip->to_irq(chip, gpio - chip->base) : -ENXIO; | |
1609 | } | |
1610 | EXPORT_SYMBOL_GPL(__gpio_to_irq); | |
1611 | ||
d2876d08 DB |
1612 | |
1613 | ||
1614 | /* There's no value in making it easy to inline GPIO calls that may sleep. | |
1615 | * Common examples include ones connected to I2C or SPI chips. | |
1616 | */ | |
1617 | ||
1618 | int gpio_get_value_cansleep(unsigned gpio) | |
1619 | { | |
1620 | struct gpio_chip *chip; | |
1621 | ||
1622 | might_sleep_if(extra_checks); | |
1623 | chip = gpio_to_chip(gpio); | |
978ccaa8 | 1624 | return chip->get ? chip->get(chip, gpio - chip->base) : 0; |
d2876d08 DB |
1625 | } |
1626 | EXPORT_SYMBOL_GPL(gpio_get_value_cansleep); | |
1627 | ||
1628 | void gpio_set_value_cansleep(unsigned gpio, int value) | |
1629 | { | |
1630 | struct gpio_chip *chip; | |
1631 | ||
1632 | might_sleep_if(extra_checks); | |
1633 | chip = gpio_to_chip(gpio); | |
1634 | chip->set(chip, gpio - chip->base, value); | |
1635 | } | |
1636 | EXPORT_SYMBOL_GPL(gpio_set_value_cansleep); | |
1637 | ||
1638 | ||
1639 | #ifdef CONFIG_DEBUG_FS | |
1640 | ||
d2876d08 DB |
1641 | static void gpiolib_dbg_show(struct seq_file *s, struct gpio_chip *chip) |
1642 | { | |
1643 | unsigned i; | |
1644 | unsigned gpio = chip->base; | |
1645 | struct gpio_desc *gdesc = &gpio_desc[gpio]; | |
1646 | int is_out; | |
1647 | ||
1648 | for (i = 0; i < chip->ngpio; i++, gpio++, gdesc++) { | |
1649 | if (!test_bit(FLAG_REQUESTED, &gdesc->flags)) | |
1650 | continue; | |
1651 | ||
1652 | is_out = test_bit(FLAG_IS_OUT, &gdesc->flags); | |
6e8ba729 | 1653 | seq_printf(s, " gpio-%-3d (%-20.20s) %s %s", |
d2876d08 DB |
1654 | gpio, gdesc->label, |
1655 | is_out ? "out" : "in ", | |
1656 | chip->get | |
1657 | ? (chip->get(chip, i) ? "hi" : "lo") | |
1658 | : "? "); | |
d2876d08 DB |
1659 | seq_printf(s, "\n"); |
1660 | } | |
1661 | } | |
1662 | ||
1663 | static int gpiolib_show(struct seq_file *s, void *unused) | |
1664 | { | |
1665 | struct gpio_chip *chip = NULL; | |
1666 | unsigned gpio; | |
1667 | int started = 0; | |
1668 | ||
1669 | /* REVISIT this isn't locked against gpio_chip removal ... */ | |
1670 | ||
e6de1808 | 1671 | for (gpio = 0; gpio_is_valid(gpio); gpio++) { |
d8f388d8 DB |
1672 | struct device *dev; |
1673 | ||
d2876d08 DB |
1674 | if (chip == gpio_desc[gpio].chip) |
1675 | continue; | |
1676 | chip = gpio_desc[gpio].chip; | |
1677 | if (!chip) | |
1678 | continue; | |
1679 | ||
d8f388d8 | 1680 | seq_printf(s, "%sGPIOs %d-%d", |
d2876d08 | 1681 | started ? "\n" : "", |
d8f388d8 DB |
1682 | chip->base, chip->base + chip->ngpio - 1); |
1683 | dev = chip->dev; | |
1684 | if (dev) | |
1685 | seq_printf(s, ", %s/%s", | |
1686 | dev->bus ? dev->bus->name : "no-bus", | |
14ab309d | 1687 | dev_name(dev)); |
d8f388d8 DB |
1688 | if (chip->label) |
1689 | seq_printf(s, ", %s", chip->label); | |
1690 | if (chip->can_sleep) | |
1691 | seq_printf(s, ", can sleep"); | |
1692 | seq_printf(s, ":\n"); | |
1693 | ||
d2876d08 DB |
1694 | started = 1; |
1695 | if (chip->dbg_show) | |
1696 | chip->dbg_show(s, chip); | |
1697 | else | |
1698 | gpiolib_dbg_show(s, chip); | |
1699 | } | |
1700 | return 0; | |
1701 | } | |
1702 | ||
1703 | static int gpiolib_open(struct inode *inode, struct file *file) | |
1704 | { | |
1705 | return single_open(file, gpiolib_show, NULL); | |
1706 | } | |
1707 | ||
828c0950 | 1708 | static const struct file_operations gpiolib_operations = { |
d2876d08 DB |
1709 | .open = gpiolib_open, |
1710 | .read = seq_read, | |
1711 | .llseek = seq_lseek, | |
1712 | .release = single_release, | |
1713 | }; | |
1714 | ||
1715 | static int __init gpiolib_debugfs_init(void) | |
1716 | { | |
1717 | /* /sys/kernel/debug/gpio */ | |
1718 | (void) debugfs_create_file("gpio", S_IFREG | S_IRUGO, | |
1719 | NULL, NULL, &gpiolib_operations); | |
1720 | return 0; | |
1721 | } | |
1722 | subsys_initcall(gpiolib_debugfs_init); | |
1723 | ||
1724 | #endif /* DEBUG_FS */ |