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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> | |
ff77c352 | 11 | #include <linux/idr.h> |
d2876d08 DB |
12 | |
13 | ||
14 | /* Optional implementation infrastructure for GPIO interfaces. | |
15 | * | |
16 | * Platforms may want to use this if they tend to use very many GPIOs | |
17 | * that aren't part of a System-On-Chip core; or across I2C/SPI/etc. | |
18 | * | |
19 | * When kernel footprint or instruction count is an issue, simpler | |
20 | * implementations may be preferred. The GPIO programming interface | |
21 | * allows for inlining speed-critical get/set operations for common | |
22 | * cases, so that access to SOC-integrated GPIOs can sometimes cost | |
23 | * only an instruction or two per bit. | |
24 | */ | |
25 | ||
26 | ||
27 | /* When debugging, extend minimal trust to callers and platform code. | |
28 | * Also emit diagnostic messages that may help initial bringup, when | |
29 | * board setup or driver bugs are most common. | |
30 | * | |
31 | * Otherwise, minimize overhead in what may be bitbanging codepaths. | |
32 | */ | |
33 | #ifdef DEBUG | |
34 | #define extra_checks 1 | |
35 | #else | |
36 | #define extra_checks 0 | |
37 | #endif | |
38 | ||
39 | /* gpio_lock prevents conflicts during gpio_desc[] table updates. | |
40 | * While any GPIO is requested, its gpio_chip is not removable; | |
41 | * each GPIO's "requested" flag serves as a lock and refcount. | |
42 | */ | |
43 | static DEFINE_SPINLOCK(gpio_lock); | |
44 | ||
45 | struct gpio_desc { | |
46 | struct gpio_chip *chip; | |
47 | unsigned long flags; | |
48 | /* flag symbols are bit numbers */ | |
49 | #define FLAG_REQUESTED 0 | |
50 | #define FLAG_IS_OUT 1 | |
169b6a7a | 51 | #define FLAG_RESERVED 2 |
d8f388d8 DB |
52 | #define FLAG_EXPORT 3 /* protected by sysfs_lock */ |
53 | #define FLAG_SYSFS 4 /* exported via /sys/class/gpio/control */ | |
ff77c352 DG |
54 | #define FLAG_TRIG_FALL 5 /* trigger on falling edge */ |
55 | #define FLAG_TRIG_RISE 6 /* trigger on rising edge */ | |
07697461 | 56 | #define FLAG_ACTIVE_LOW 7 /* sysfs value has active low */ |
ff77c352 DG |
57 | |
58 | #define PDESC_ID_SHIFT 16 /* add new flags before this one */ | |
59 | ||
60 | #define GPIO_FLAGS_MASK ((1 << PDESC_ID_SHIFT) - 1) | |
61 | #define GPIO_TRIGGER_MASK (BIT(FLAG_TRIG_FALL) | BIT(FLAG_TRIG_RISE)) | |
d2876d08 DB |
62 | |
63 | #ifdef CONFIG_DEBUG_FS | |
64 | const char *label; | |
65 | #endif | |
66 | }; | |
67 | static struct gpio_desc gpio_desc[ARCH_NR_GPIOS]; | |
68 | ||
ff77c352 DG |
69 | #ifdef CONFIG_GPIO_SYSFS |
70 | struct poll_desc { | |
71 | struct work_struct work; | |
72 | struct sysfs_dirent *value_sd; | |
73 | }; | |
74 | ||
75 | static struct idr pdesc_idr; | |
76 | #endif | |
77 | ||
d2876d08 DB |
78 | static inline void desc_set_label(struct gpio_desc *d, const char *label) |
79 | { | |
80 | #ifdef CONFIG_DEBUG_FS | |
81 | d->label = label; | |
82 | #endif | |
83 | } | |
84 | ||
85 | /* Warn when drivers omit gpio_request() calls -- legal but ill-advised | |
86 | * when setting direction, and otherwise illegal. Until board setup code | |
87 | * and drivers use explicit requests everywhere (which won't happen when | |
88 | * those calls have no teeth) we can't avoid autorequesting. This nag | |
35e8bb51 DB |
89 | * message should motivate switching to explicit requests... so should |
90 | * the weaker cleanup after faults, compared to gpio_request(). | |
8a0cecff DB |
91 | * |
92 | * NOTE: the autorequest mechanism is going away; at this point it's | |
93 | * only "legal" in the sense that (old) code using it won't break yet, | |
94 | * but instead only triggers a WARN() stack dump. | |
d2876d08 | 95 | */ |
35e8bb51 | 96 | static int gpio_ensure_requested(struct gpio_desc *desc, unsigned offset) |
d2876d08 | 97 | { |
8a0cecff DB |
98 | const struct gpio_chip *chip = desc->chip; |
99 | const int gpio = chip->base + offset; | |
35e8bb51 | 100 | |
8a0cecff DB |
101 | if (WARN(test_and_set_bit(FLAG_REQUESTED, &desc->flags) == 0, |
102 | "autorequest GPIO-%d\n", gpio)) { | |
35e8bb51 DB |
103 | if (!try_module_get(chip->owner)) { |
104 | pr_err("GPIO-%d: module can't be gotten \n", gpio); | |
105 | clear_bit(FLAG_REQUESTED, &desc->flags); | |
106 | /* lose */ | |
107 | return -EIO; | |
108 | } | |
d2876d08 | 109 | desc_set_label(desc, "[auto]"); |
35e8bb51 DB |
110 | /* caller must chip->request() w/o spinlock */ |
111 | if (chip->request) | |
112 | return 1; | |
d2876d08 | 113 | } |
35e8bb51 | 114 | return 0; |
d2876d08 DB |
115 | } |
116 | ||
117 | /* caller holds gpio_lock *OR* gpio is marked as requested */ | |
118 | static inline struct gpio_chip *gpio_to_chip(unsigned gpio) | |
119 | { | |
120 | return gpio_desc[gpio].chip; | |
121 | } | |
122 | ||
8d0aab2f AV |
123 | /* dynamic allocation of GPIOs, e.g. on a hotplugged device */ |
124 | static int gpiochip_find_base(int ngpio) | |
125 | { | |
126 | int i; | |
127 | int spare = 0; | |
128 | int base = -ENOSPC; | |
129 | ||
130 | for (i = ARCH_NR_GPIOS - 1; i >= 0 ; i--) { | |
169b6a7a AV |
131 | struct gpio_desc *desc = &gpio_desc[i]; |
132 | struct gpio_chip *chip = desc->chip; | |
8d0aab2f | 133 | |
169b6a7a | 134 | if (!chip && !test_bit(FLAG_RESERVED, &desc->flags)) { |
8d0aab2f AV |
135 | spare++; |
136 | if (spare == ngpio) { | |
137 | base = i; | |
138 | break; | |
139 | } | |
140 | } else { | |
141 | spare = 0; | |
169b6a7a AV |
142 | if (chip) |
143 | i -= chip->ngpio - 1; | |
8d0aab2f AV |
144 | } |
145 | } | |
146 | ||
147 | if (gpio_is_valid(base)) | |
148 | pr_debug("%s: found new base at %d\n", __func__, base); | |
149 | return base; | |
150 | } | |
151 | ||
169b6a7a AV |
152 | /** |
153 | * gpiochip_reserve() - reserve range of gpios to use with platform code only | |
154 | * @start: starting gpio number | |
155 | * @ngpio: number of gpios to reserve | |
156 | * Context: platform init, potentially before irqs or kmalloc will work | |
157 | * | |
158 | * Returns a negative errno if any gpio within the range is already reserved | |
159 | * or registered, else returns zero as a success code. Use this function | |
160 | * to mark a range of gpios as unavailable for dynamic gpio number allocation, | |
161 | * for example because its driver support is not yet loaded. | |
162 | */ | |
163 | int __init gpiochip_reserve(int start, int ngpio) | |
164 | { | |
165 | int ret = 0; | |
166 | unsigned long flags; | |
167 | int i; | |
168 | ||
bff5fda9 | 169 | if (!gpio_is_valid(start) || !gpio_is_valid(start + ngpio - 1)) |
169b6a7a AV |
170 | return -EINVAL; |
171 | ||
172 | spin_lock_irqsave(&gpio_lock, flags); | |
173 | ||
174 | for (i = start; i < start + ngpio; i++) { | |
175 | struct gpio_desc *desc = &gpio_desc[i]; | |
176 | ||
177 | if (desc->chip || test_bit(FLAG_RESERVED, &desc->flags)) { | |
178 | ret = -EBUSY; | |
179 | goto err; | |
180 | } | |
181 | ||
182 | set_bit(FLAG_RESERVED, &desc->flags); | |
183 | } | |
184 | ||
185 | pr_debug("%s: reserved gpios from %d to %d\n", | |
186 | __func__, start, start + ngpio - 1); | |
187 | err: | |
188 | spin_unlock_irqrestore(&gpio_lock, flags); | |
189 | ||
190 | return ret; | |
191 | } | |
192 | ||
d8f388d8 DB |
193 | #ifdef CONFIG_GPIO_SYSFS |
194 | ||
195 | /* lock protects against unexport_gpio() being called while | |
196 | * sysfs files are active. | |
197 | */ | |
198 | static DEFINE_MUTEX(sysfs_lock); | |
199 | ||
200 | /* | |
201 | * /sys/class/gpio/gpioN... only for GPIOs that are exported | |
202 | * /direction | |
203 | * * MAY BE OMITTED if kernel won't allow direction changes | |
204 | * * is read/write as "in" or "out" | |
205 | * * may also be written as "high" or "low", initializing | |
206 | * output value as specified ("out" implies "low") | |
207 | * /value | |
208 | * * always readable, subject to hardware behavior | |
209 | * * may be writable, as zero/nonzero | |
ff77c352 DG |
210 | * /edge |
211 | * * configures behavior of poll(2) on /value | |
212 | * * available only if pin can generate IRQs on input | |
213 | * * is read/write as "none", "falling", "rising", or "both" | |
07697461 JN |
214 | * /active_low |
215 | * * configures polarity of /value | |
216 | * * is read/write as zero/nonzero | |
217 | * * also affects existing and subsequent "falling" and "rising" | |
218 | * /edge configuration | |
d8f388d8 DB |
219 | */ |
220 | ||
221 | static ssize_t gpio_direction_show(struct device *dev, | |
222 | struct device_attribute *attr, char *buf) | |
223 | { | |
224 | const struct gpio_desc *desc = dev_get_drvdata(dev); | |
225 | ssize_t status; | |
226 | ||
227 | mutex_lock(&sysfs_lock); | |
228 | ||
229 | if (!test_bit(FLAG_EXPORT, &desc->flags)) | |
230 | status = -EIO; | |
231 | else | |
232 | status = sprintf(buf, "%s\n", | |
233 | test_bit(FLAG_IS_OUT, &desc->flags) | |
234 | ? "out" : "in"); | |
235 | ||
236 | mutex_unlock(&sysfs_lock); | |
237 | return status; | |
238 | } | |
239 | ||
240 | static ssize_t gpio_direction_store(struct device *dev, | |
241 | struct device_attribute *attr, const char *buf, size_t size) | |
242 | { | |
243 | const struct gpio_desc *desc = dev_get_drvdata(dev); | |
244 | unsigned gpio = desc - gpio_desc; | |
245 | ssize_t status; | |
246 | ||
247 | mutex_lock(&sysfs_lock); | |
248 | ||
249 | if (!test_bit(FLAG_EXPORT, &desc->flags)) | |
250 | status = -EIO; | |
251 | else if (sysfs_streq(buf, "high")) | |
252 | status = gpio_direction_output(gpio, 1); | |
253 | else if (sysfs_streq(buf, "out") || sysfs_streq(buf, "low")) | |
254 | status = gpio_direction_output(gpio, 0); | |
255 | else if (sysfs_streq(buf, "in")) | |
256 | status = gpio_direction_input(gpio); | |
257 | else | |
258 | status = -EINVAL; | |
259 | ||
260 | mutex_unlock(&sysfs_lock); | |
261 | return status ? : size; | |
262 | } | |
263 | ||
07697461 | 264 | static /* const */ DEVICE_ATTR(direction, 0644, |
d8f388d8 DB |
265 | gpio_direction_show, gpio_direction_store); |
266 | ||
267 | static ssize_t gpio_value_show(struct device *dev, | |
268 | struct device_attribute *attr, char *buf) | |
269 | { | |
270 | const struct gpio_desc *desc = dev_get_drvdata(dev); | |
271 | unsigned gpio = desc - gpio_desc; | |
272 | ssize_t status; | |
273 | ||
274 | mutex_lock(&sysfs_lock); | |
275 | ||
07697461 | 276 | if (!test_bit(FLAG_EXPORT, &desc->flags)) { |
d8f388d8 | 277 | status = -EIO; |
07697461 JN |
278 | } else { |
279 | int value; | |
280 | ||
281 | value = !!gpio_get_value_cansleep(gpio); | |
282 | if (test_bit(FLAG_ACTIVE_LOW, &desc->flags)) | |
283 | value = !value; | |
284 | ||
285 | status = sprintf(buf, "%d\n", value); | |
286 | } | |
d8f388d8 DB |
287 | |
288 | mutex_unlock(&sysfs_lock); | |
289 | return status; | |
290 | } | |
291 | ||
292 | static ssize_t gpio_value_store(struct device *dev, | |
293 | struct device_attribute *attr, const char *buf, size_t size) | |
294 | { | |
295 | const struct gpio_desc *desc = dev_get_drvdata(dev); | |
296 | unsigned gpio = desc - gpio_desc; | |
297 | ssize_t status; | |
298 | ||
299 | mutex_lock(&sysfs_lock); | |
300 | ||
301 | if (!test_bit(FLAG_EXPORT, &desc->flags)) | |
302 | status = -EIO; | |
303 | else if (!test_bit(FLAG_IS_OUT, &desc->flags)) | |
304 | status = -EPERM; | |
305 | else { | |
306 | long value; | |
307 | ||
308 | status = strict_strtol(buf, 0, &value); | |
309 | if (status == 0) { | |
07697461 JN |
310 | if (test_bit(FLAG_ACTIVE_LOW, &desc->flags)) |
311 | value = !value; | |
d8f388d8 DB |
312 | gpio_set_value_cansleep(gpio, value != 0); |
313 | status = size; | |
314 | } | |
315 | } | |
316 | ||
317 | mutex_unlock(&sysfs_lock); | |
318 | return status; | |
319 | } | |
320 | ||
07697461 | 321 | static const DEVICE_ATTR(value, 0644, |
d8f388d8 DB |
322 | gpio_value_show, gpio_value_store); |
323 | ||
ff77c352 DG |
324 | static irqreturn_t gpio_sysfs_irq(int irq, void *priv) |
325 | { | |
326 | struct work_struct *work = priv; | |
327 | ||
328 | schedule_work(work); | |
329 | return IRQ_HANDLED; | |
330 | } | |
331 | ||
332 | static void gpio_notify_sysfs(struct work_struct *work) | |
333 | { | |
334 | struct poll_desc *pdesc; | |
335 | ||
336 | pdesc = container_of(work, struct poll_desc, work); | |
337 | sysfs_notify_dirent(pdesc->value_sd); | |
338 | } | |
339 | ||
340 | static int gpio_setup_irq(struct gpio_desc *desc, struct device *dev, | |
341 | unsigned long gpio_flags) | |
342 | { | |
343 | struct poll_desc *pdesc; | |
344 | unsigned long irq_flags; | |
345 | int ret, irq, id; | |
346 | ||
347 | if ((desc->flags & GPIO_TRIGGER_MASK) == gpio_flags) | |
348 | return 0; | |
349 | ||
350 | irq = gpio_to_irq(desc - gpio_desc); | |
351 | if (irq < 0) | |
352 | return -EIO; | |
353 | ||
354 | id = desc->flags >> PDESC_ID_SHIFT; | |
355 | pdesc = idr_find(&pdesc_idr, id); | |
356 | if (pdesc) { | |
357 | free_irq(irq, &pdesc->work); | |
358 | cancel_work_sync(&pdesc->work); | |
359 | } | |
360 | ||
361 | desc->flags &= ~GPIO_TRIGGER_MASK; | |
362 | ||
363 | if (!gpio_flags) { | |
364 | ret = 0; | |
365 | goto free_sd; | |
366 | } | |
367 | ||
368 | irq_flags = IRQF_SHARED; | |
369 | if (test_bit(FLAG_TRIG_FALL, &gpio_flags)) | |
07697461 JN |
370 | irq_flags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ? |
371 | IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING; | |
ff77c352 | 372 | if (test_bit(FLAG_TRIG_RISE, &gpio_flags)) |
07697461 JN |
373 | irq_flags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ? |
374 | IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING; | |
ff77c352 DG |
375 | |
376 | if (!pdesc) { | |
377 | pdesc = kmalloc(sizeof(*pdesc), GFP_KERNEL); | |
378 | if (!pdesc) { | |
379 | ret = -ENOMEM; | |
380 | goto err_out; | |
381 | } | |
382 | ||
383 | do { | |
384 | ret = -ENOMEM; | |
385 | if (idr_pre_get(&pdesc_idr, GFP_KERNEL)) | |
386 | ret = idr_get_new_above(&pdesc_idr, | |
387 | pdesc, 1, &id); | |
388 | } while (ret == -EAGAIN); | |
389 | ||
390 | if (ret) | |
391 | goto free_mem; | |
392 | ||
393 | desc->flags &= GPIO_FLAGS_MASK; | |
394 | desc->flags |= (unsigned long)id << PDESC_ID_SHIFT; | |
395 | ||
396 | if (desc->flags >> PDESC_ID_SHIFT != id) { | |
397 | ret = -ERANGE; | |
398 | goto free_id; | |
399 | } | |
400 | ||
401 | pdesc->value_sd = sysfs_get_dirent(dev->kobj.sd, "value"); | |
402 | if (!pdesc->value_sd) { | |
403 | ret = -ENODEV; | |
404 | goto free_id; | |
405 | } | |
406 | INIT_WORK(&pdesc->work, gpio_notify_sysfs); | |
407 | } | |
408 | ||
409 | ret = request_irq(irq, gpio_sysfs_irq, irq_flags, | |
410 | "gpiolib", &pdesc->work); | |
411 | if (ret) | |
412 | goto free_sd; | |
413 | ||
414 | desc->flags |= gpio_flags; | |
415 | return 0; | |
416 | ||
417 | free_sd: | |
418 | sysfs_put(pdesc->value_sd); | |
419 | free_id: | |
420 | idr_remove(&pdesc_idr, id); | |
421 | desc->flags &= GPIO_FLAGS_MASK; | |
422 | free_mem: | |
423 | kfree(pdesc); | |
424 | err_out: | |
425 | return ret; | |
426 | } | |
427 | ||
428 | static const struct { | |
429 | const char *name; | |
430 | unsigned long flags; | |
431 | } trigger_types[] = { | |
432 | { "none", 0 }, | |
433 | { "falling", BIT(FLAG_TRIG_FALL) }, | |
434 | { "rising", BIT(FLAG_TRIG_RISE) }, | |
435 | { "both", BIT(FLAG_TRIG_FALL) | BIT(FLAG_TRIG_RISE) }, | |
436 | }; | |
437 | ||
438 | static ssize_t gpio_edge_show(struct device *dev, | |
439 | struct device_attribute *attr, char *buf) | |
440 | { | |
441 | const struct gpio_desc *desc = dev_get_drvdata(dev); | |
442 | ssize_t status; | |
443 | ||
444 | mutex_lock(&sysfs_lock); | |
445 | ||
446 | if (!test_bit(FLAG_EXPORT, &desc->flags)) | |
447 | status = -EIO; | |
448 | else { | |
449 | int i; | |
450 | ||
451 | status = 0; | |
452 | for (i = 0; i < ARRAY_SIZE(trigger_types); i++) | |
453 | if ((desc->flags & GPIO_TRIGGER_MASK) | |
454 | == trigger_types[i].flags) { | |
455 | status = sprintf(buf, "%s\n", | |
456 | trigger_types[i].name); | |
457 | break; | |
458 | } | |
459 | } | |
460 | ||
461 | mutex_unlock(&sysfs_lock); | |
462 | return status; | |
463 | } | |
464 | ||
465 | static ssize_t gpio_edge_store(struct device *dev, | |
466 | struct device_attribute *attr, const char *buf, size_t size) | |
467 | { | |
468 | struct gpio_desc *desc = dev_get_drvdata(dev); | |
469 | ssize_t status; | |
470 | int i; | |
471 | ||
472 | for (i = 0; i < ARRAY_SIZE(trigger_types); i++) | |
473 | if (sysfs_streq(trigger_types[i].name, buf)) | |
474 | goto found; | |
475 | return -EINVAL; | |
476 | ||
477 | found: | |
478 | mutex_lock(&sysfs_lock); | |
479 | ||
480 | if (!test_bit(FLAG_EXPORT, &desc->flags)) | |
481 | status = -EIO; | |
482 | else { | |
483 | status = gpio_setup_irq(desc, dev, trigger_types[i].flags); | |
484 | if (!status) | |
485 | status = size; | |
486 | } | |
487 | ||
488 | mutex_unlock(&sysfs_lock); | |
489 | ||
490 | return status; | |
491 | } | |
492 | ||
493 | static DEVICE_ATTR(edge, 0644, gpio_edge_show, gpio_edge_store); | |
494 | ||
07697461 JN |
495 | static int sysfs_set_active_low(struct gpio_desc *desc, struct device *dev, |
496 | int value) | |
497 | { | |
498 | int status = 0; | |
499 | ||
500 | if (!!test_bit(FLAG_ACTIVE_LOW, &desc->flags) == !!value) | |
501 | return 0; | |
502 | ||
503 | if (value) | |
504 | set_bit(FLAG_ACTIVE_LOW, &desc->flags); | |
505 | else | |
506 | clear_bit(FLAG_ACTIVE_LOW, &desc->flags); | |
507 | ||
508 | /* reconfigure poll(2) support if enabled on one edge only */ | |
509 | if (dev != NULL && (!!test_bit(FLAG_TRIG_RISE, &desc->flags) ^ | |
510 | !!test_bit(FLAG_TRIG_FALL, &desc->flags))) { | |
511 | unsigned long trigger_flags = desc->flags & GPIO_TRIGGER_MASK; | |
512 | ||
513 | gpio_setup_irq(desc, dev, 0); | |
514 | status = gpio_setup_irq(desc, dev, trigger_flags); | |
515 | } | |
516 | ||
517 | return status; | |
518 | } | |
519 | ||
520 | static ssize_t gpio_active_low_show(struct device *dev, | |
521 | struct device_attribute *attr, char *buf) | |
522 | { | |
523 | const struct gpio_desc *desc = dev_get_drvdata(dev); | |
524 | ssize_t status; | |
525 | ||
526 | mutex_lock(&sysfs_lock); | |
527 | ||
528 | if (!test_bit(FLAG_EXPORT, &desc->flags)) | |
529 | status = -EIO; | |
530 | else | |
531 | status = sprintf(buf, "%d\n", | |
532 | !!test_bit(FLAG_ACTIVE_LOW, &desc->flags)); | |
533 | ||
534 | mutex_unlock(&sysfs_lock); | |
535 | ||
536 | return status; | |
537 | } | |
538 | ||
539 | static ssize_t gpio_active_low_store(struct device *dev, | |
540 | struct device_attribute *attr, const char *buf, size_t size) | |
541 | { | |
542 | struct gpio_desc *desc = dev_get_drvdata(dev); | |
543 | ssize_t status; | |
544 | ||
545 | mutex_lock(&sysfs_lock); | |
546 | ||
547 | if (!test_bit(FLAG_EXPORT, &desc->flags)) { | |
548 | status = -EIO; | |
549 | } else { | |
550 | long value; | |
551 | ||
552 | status = strict_strtol(buf, 0, &value); | |
553 | if (status == 0) | |
554 | status = sysfs_set_active_low(desc, dev, value != 0); | |
555 | } | |
556 | ||
557 | mutex_unlock(&sysfs_lock); | |
558 | ||
559 | return status ? : size; | |
560 | } | |
561 | ||
562 | static const DEVICE_ATTR(active_low, 0644, | |
563 | gpio_active_low_show, gpio_active_low_store); | |
564 | ||
d8f388d8 | 565 | static const struct attribute *gpio_attrs[] = { |
d8f388d8 | 566 | &dev_attr_value.attr, |
07697461 | 567 | &dev_attr_active_low.attr, |
d8f388d8 DB |
568 | NULL, |
569 | }; | |
570 | ||
571 | static const struct attribute_group gpio_attr_group = { | |
572 | .attrs = (struct attribute **) gpio_attrs, | |
573 | }; | |
574 | ||
575 | /* | |
576 | * /sys/class/gpio/gpiochipN/ | |
577 | * /base ... matching gpio_chip.base (N) | |
578 | * /label ... matching gpio_chip.label | |
579 | * /ngpio ... matching gpio_chip.ngpio | |
580 | */ | |
581 | ||
582 | static ssize_t chip_base_show(struct device *dev, | |
583 | struct device_attribute *attr, char *buf) | |
584 | { | |
585 | const struct gpio_chip *chip = dev_get_drvdata(dev); | |
586 | ||
587 | return sprintf(buf, "%d\n", chip->base); | |
588 | } | |
589 | static DEVICE_ATTR(base, 0444, chip_base_show, NULL); | |
590 | ||
591 | static ssize_t chip_label_show(struct device *dev, | |
592 | struct device_attribute *attr, char *buf) | |
593 | { | |
594 | const struct gpio_chip *chip = dev_get_drvdata(dev); | |
595 | ||
596 | return sprintf(buf, "%s\n", chip->label ? : ""); | |
597 | } | |
598 | static DEVICE_ATTR(label, 0444, chip_label_show, NULL); | |
599 | ||
600 | static ssize_t chip_ngpio_show(struct device *dev, | |
601 | struct device_attribute *attr, char *buf) | |
602 | { | |
603 | const struct gpio_chip *chip = dev_get_drvdata(dev); | |
604 | ||
605 | return sprintf(buf, "%u\n", chip->ngpio); | |
606 | } | |
607 | static DEVICE_ATTR(ngpio, 0444, chip_ngpio_show, NULL); | |
608 | ||
609 | static const struct attribute *gpiochip_attrs[] = { | |
610 | &dev_attr_base.attr, | |
611 | &dev_attr_label.attr, | |
612 | &dev_attr_ngpio.attr, | |
613 | NULL, | |
614 | }; | |
615 | ||
616 | static const struct attribute_group gpiochip_attr_group = { | |
617 | .attrs = (struct attribute **) gpiochip_attrs, | |
618 | }; | |
619 | ||
620 | /* | |
621 | * /sys/class/gpio/export ... write-only | |
622 | * integer N ... number of GPIO to export (full access) | |
623 | * /sys/class/gpio/unexport ... write-only | |
624 | * integer N ... number of GPIO to unexport | |
625 | */ | |
626 | static ssize_t export_store(struct class *class, const char *buf, size_t len) | |
627 | { | |
628 | long gpio; | |
629 | int status; | |
630 | ||
631 | status = strict_strtol(buf, 0, &gpio); | |
632 | if (status < 0) | |
633 | goto done; | |
634 | ||
635 | /* No extra locking here; FLAG_SYSFS just signifies that the | |
636 | * request and export were done by on behalf of userspace, so | |
637 | * they may be undone on its behalf too. | |
638 | */ | |
639 | ||
640 | status = gpio_request(gpio, "sysfs"); | |
641 | if (status < 0) | |
642 | goto done; | |
643 | ||
644 | status = gpio_export(gpio, true); | |
645 | if (status < 0) | |
646 | gpio_free(gpio); | |
647 | else | |
648 | set_bit(FLAG_SYSFS, &gpio_desc[gpio].flags); | |
649 | ||
650 | done: | |
651 | if (status) | |
652 | pr_debug("%s: status %d\n", __func__, status); | |
653 | return status ? : len; | |
654 | } | |
655 | ||
656 | static ssize_t unexport_store(struct class *class, const char *buf, size_t len) | |
657 | { | |
658 | long gpio; | |
659 | int status; | |
660 | ||
661 | status = strict_strtol(buf, 0, &gpio); | |
662 | if (status < 0) | |
663 | goto done; | |
664 | ||
665 | status = -EINVAL; | |
666 | ||
667 | /* reject bogus commands (gpio_unexport ignores them) */ | |
668 | if (!gpio_is_valid(gpio)) | |
669 | goto done; | |
670 | ||
671 | /* No extra locking here; FLAG_SYSFS just signifies that the | |
672 | * request and export were done by on behalf of userspace, so | |
673 | * they may be undone on its behalf too. | |
674 | */ | |
675 | if (test_and_clear_bit(FLAG_SYSFS, &gpio_desc[gpio].flags)) { | |
676 | status = 0; | |
677 | gpio_free(gpio); | |
678 | } | |
679 | done: | |
680 | if (status) | |
681 | pr_debug("%s: status %d\n", __func__, status); | |
682 | return status ? : len; | |
683 | } | |
684 | ||
685 | static struct class_attribute gpio_class_attrs[] = { | |
686 | __ATTR(export, 0200, NULL, export_store), | |
687 | __ATTR(unexport, 0200, NULL, unexport_store), | |
688 | __ATTR_NULL, | |
689 | }; | |
690 | ||
691 | static struct class gpio_class = { | |
692 | .name = "gpio", | |
693 | .owner = THIS_MODULE, | |
694 | ||
695 | .class_attrs = gpio_class_attrs, | |
696 | }; | |
697 | ||
698 | ||
699 | /** | |
700 | * gpio_export - export a GPIO through sysfs | |
701 | * @gpio: gpio to make available, already requested | |
702 | * @direction_may_change: true if userspace may change gpio direction | |
703 | * Context: arch_initcall or later | |
704 | * | |
705 | * When drivers want to make a GPIO accessible to userspace after they | |
706 | * have requested it -- perhaps while debugging, or as part of their | |
707 | * public interface -- they may use this routine. If the GPIO can | |
708 | * change direction (some can't) and the caller allows it, userspace | |
709 | * will see "direction" sysfs attribute which may be used to change | |
710 | * the gpio's direction. A "value" attribute will always be provided. | |
711 | * | |
712 | * Returns zero on success, else an error. | |
713 | */ | |
714 | int gpio_export(unsigned gpio, bool direction_may_change) | |
715 | { | |
716 | unsigned long flags; | |
717 | struct gpio_desc *desc; | |
718 | int status = -EINVAL; | |
926b663c | 719 | char *ioname = NULL; |
d8f388d8 DB |
720 | |
721 | /* can't export until sysfs is available ... */ | |
722 | if (!gpio_class.p) { | |
723 | pr_debug("%s: called too early!\n", __func__); | |
724 | return -ENOENT; | |
725 | } | |
726 | ||
727 | if (!gpio_is_valid(gpio)) | |
728 | goto done; | |
729 | ||
730 | mutex_lock(&sysfs_lock); | |
731 | ||
732 | spin_lock_irqsave(&gpio_lock, flags); | |
733 | desc = &gpio_desc[gpio]; | |
734 | if (test_bit(FLAG_REQUESTED, &desc->flags) | |
735 | && !test_bit(FLAG_EXPORT, &desc->flags)) { | |
736 | status = 0; | |
737 | if (!desc->chip->direction_input | |
738 | || !desc->chip->direction_output) | |
739 | direction_may_change = false; | |
740 | } | |
741 | spin_unlock_irqrestore(&gpio_lock, flags); | |
742 | ||
926b663c DS |
743 | if (desc->chip->names && desc->chip->names[gpio - desc->chip->base]) |
744 | ioname = desc->chip->names[gpio - desc->chip->base]; | |
745 | ||
d8f388d8 DB |
746 | if (status == 0) { |
747 | struct device *dev; | |
748 | ||
749 | dev = device_create(&gpio_class, desc->chip->dev, MKDEV(0, 0), | |
ff77c352 | 750 | desc, ioname ? ioname : "gpio%d", gpio); |
d62668e1 | 751 | if (!IS_ERR(dev)) { |
07697461 | 752 | status = sysfs_create_group(&dev->kobj, |
d8f388d8 | 753 | &gpio_attr_group); |
07697461 JN |
754 | |
755 | if (!status && direction_may_change) | |
d8f388d8 | 756 | status = device_create_file(dev, |
07697461 | 757 | &dev_attr_direction); |
ff77c352 DG |
758 | |
759 | if (!status && gpio_to_irq(gpio) >= 0 | |
760 | && (direction_may_change | |
761 | || !test_bit(FLAG_IS_OUT, | |
762 | &desc->flags))) | |
763 | status = device_create_file(dev, | |
764 | &dev_attr_edge); | |
765 | ||
d8f388d8 DB |
766 | if (status != 0) |
767 | device_unregister(dev); | |
768 | } else | |
d62668e1 | 769 | status = PTR_ERR(dev); |
d8f388d8 DB |
770 | if (status == 0) |
771 | set_bit(FLAG_EXPORT, &desc->flags); | |
772 | } | |
773 | ||
774 | mutex_unlock(&sysfs_lock); | |
775 | ||
776 | done: | |
777 | if (status) | |
778 | pr_debug("%s: gpio%d status %d\n", __func__, gpio, status); | |
779 | ||
780 | return status; | |
781 | } | |
782 | EXPORT_SYMBOL_GPL(gpio_export); | |
783 | ||
784 | static int match_export(struct device *dev, void *data) | |
785 | { | |
786 | return dev_get_drvdata(dev) == data; | |
787 | } | |
788 | ||
a4177ee7 JN |
789 | /** |
790 | * gpio_export_link - create a sysfs link to an exported GPIO node | |
791 | * @dev: device under which to create symlink | |
792 | * @name: name of the symlink | |
793 | * @gpio: gpio to create symlink to, already exported | |
794 | * | |
795 | * Set up a symlink from /sys/.../dev/name to /sys/class/gpio/gpioN | |
796 | * node. Caller is responsible for unlinking. | |
797 | * | |
798 | * Returns zero on success, else an error. | |
799 | */ | |
800 | int gpio_export_link(struct device *dev, const char *name, unsigned gpio) | |
801 | { | |
802 | struct gpio_desc *desc; | |
803 | int status = -EINVAL; | |
804 | ||
805 | if (!gpio_is_valid(gpio)) | |
806 | goto done; | |
807 | ||
808 | mutex_lock(&sysfs_lock); | |
809 | ||
810 | desc = &gpio_desc[gpio]; | |
811 | ||
812 | if (test_bit(FLAG_EXPORT, &desc->flags)) { | |
813 | struct device *tdev; | |
814 | ||
815 | tdev = class_find_device(&gpio_class, NULL, desc, match_export); | |
816 | if (tdev != NULL) { | |
817 | status = sysfs_create_link(&dev->kobj, &tdev->kobj, | |
818 | name); | |
819 | } else { | |
820 | status = -ENODEV; | |
821 | } | |
822 | } | |
823 | ||
824 | mutex_unlock(&sysfs_lock); | |
825 | ||
826 | done: | |
827 | if (status) | |
828 | pr_debug("%s: gpio%d status %d\n", __func__, gpio, status); | |
829 | ||
830 | return status; | |
831 | } | |
832 | EXPORT_SYMBOL_GPL(gpio_export_link); | |
833 | ||
07697461 JN |
834 | |
835 | /** | |
836 | * gpio_sysfs_set_active_low - set the polarity of gpio sysfs value | |
837 | * @gpio: gpio to change | |
838 | * @value: non-zero to use active low, i.e. inverted values | |
839 | * | |
840 | * Set the polarity of /sys/class/gpio/gpioN/value sysfs attribute. | |
841 | * The GPIO does not have to be exported yet. If poll(2) support has | |
842 | * been enabled for either rising or falling edge, it will be | |
843 | * reconfigured to follow the new polarity. | |
844 | * | |
845 | * Returns zero on success, else an error. | |
846 | */ | |
847 | int gpio_sysfs_set_active_low(unsigned gpio, int value) | |
848 | { | |
849 | struct gpio_desc *desc; | |
850 | struct device *dev = NULL; | |
851 | int status = -EINVAL; | |
852 | ||
853 | if (!gpio_is_valid(gpio)) | |
854 | goto done; | |
855 | ||
856 | mutex_lock(&sysfs_lock); | |
857 | ||
858 | desc = &gpio_desc[gpio]; | |
859 | ||
860 | if (test_bit(FLAG_EXPORT, &desc->flags)) { | |
07697461 JN |
861 | dev = class_find_device(&gpio_class, NULL, desc, match_export); |
862 | if (dev == NULL) { | |
863 | status = -ENODEV; | |
864 | goto unlock; | |
865 | } | |
866 | } | |
867 | ||
868 | status = sysfs_set_active_low(desc, dev, value); | |
869 | ||
870 | unlock: | |
871 | mutex_unlock(&sysfs_lock); | |
872 | ||
873 | done: | |
874 | if (status) | |
875 | pr_debug("%s: gpio%d status %d\n", __func__, gpio, status); | |
876 | ||
877 | return status; | |
878 | } | |
879 | EXPORT_SYMBOL_GPL(gpio_sysfs_set_active_low); | |
880 | ||
d8f388d8 DB |
881 | /** |
882 | * gpio_unexport - reverse effect of gpio_export() | |
883 | * @gpio: gpio to make unavailable | |
884 | * | |
885 | * This is implicit on gpio_free(). | |
886 | */ | |
887 | void gpio_unexport(unsigned gpio) | |
888 | { | |
889 | struct gpio_desc *desc; | |
890 | int status = -EINVAL; | |
891 | ||
892 | if (!gpio_is_valid(gpio)) | |
893 | goto done; | |
894 | ||
895 | mutex_lock(&sysfs_lock); | |
896 | ||
897 | desc = &gpio_desc[gpio]; | |
926b663c | 898 | |
d8f388d8 DB |
899 | if (test_bit(FLAG_EXPORT, &desc->flags)) { |
900 | struct device *dev = NULL; | |
901 | ||
902 | dev = class_find_device(&gpio_class, NULL, desc, match_export); | |
903 | if (dev) { | |
ff77c352 | 904 | gpio_setup_irq(desc, dev, 0); |
d8f388d8 DB |
905 | clear_bit(FLAG_EXPORT, &desc->flags); |
906 | put_device(dev); | |
907 | device_unregister(dev); | |
908 | status = 0; | |
909 | } else | |
910 | status = -ENODEV; | |
911 | } | |
912 | ||
913 | mutex_unlock(&sysfs_lock); | |
914 | done: | |
915 | if (status) | |
916 | pr_debug("%s: gpio%d status %d\n", __func__, gpio, status); | |
917 | } | |
918 | EXPORT_SYMBOL_GPL(gpio_unexport); | |
919 | ||
920 | static int gpiochip_export(struct gpio_chip *chip) | |
921 | { | |
922 | int status; | |
923 | struct device *dev; | |
924 | ||
925 | /* Many systems register gpio chips for SOC support very early, | |
926 | * before driver model support is available. In those cases we | |
927 | * export this later, in gpiolib_sysfs_init() ... here we just | |
928 | * verify that _some_ field of gpio_class got initialized. | |
929 | */ | |
930 | if (!gpio_class.p) | |
931 | return 0; | |
932 | ||
933 | /* use chip->base for the ID; it's already known to be unique */ | |
934 | mutex_lock(&sysfs_lock); | |
935 | dev = device_create(&gpio_class, chip->dev, MKDEV(0, 0), chip, | |
936 | "gpiochip%d", chip->base); | |
d62668e1 | 937 | if (!IS_ERR(dev)) { |
d8f388d8 DB |
938 | status = sysfs_create_group(&dev->kobj, |
939 | &gpiochip_attr_group); | |
940 | } else | |
d62668e1 | 941 | status = PTR_ERR(dev); |
d8f388d8 DB |
942 | chip->exported = (status == 0); |
943 | mutex_unlock(&sysfs_lock); | |
944 | ||
945 | if (status) { | |
946 | unsigned long flags; | |
947 | unsigned gpio; | |
948 | ||
949 | spin_lock_irqsave(&gpio_lock, flags); | |
950 | gpio = chip->base; | |
951 | while (gpio_desc[gpio].chip == chip) | |
952 | gpio_desc[gpio++].chip = NULL; | |
953 | spin_unlock_irqrestore(&gpio_lock, flags); | |
954 | ||
955 | pr_debug("%s: chip %s status %d\n", __func__, | |
956 | chip->label, status); | |
957 | } | |
958 | ||
959 | return status; | |
960 | } | |
961 | ||
962 | static void gpiochip_unexport(struct gpio_chip *chip) | |
963 | { | |
964 | int status; | |
965 | struct device *dev; | |
966 | ||
967 | mutex_lock(&sysfs_lock); | |
968 | dev = class_find_device(&gpio_class, NULL, chip, match_export); | |
969 | if (dev) { | |
970 | put_device(dev); | |
971 | device_unregister(dev); | |
972 | chip->exported = 0; | |
973 | status = 0; | |
974 | } else | |
975 | status = -ENODEV; | |
976 | mutex_unlock(&sysfs_lock); | |
977 | ||
978 | if (status) | |
979 | pr_debug("%s: chip %s status %d\n", __func__, | |
980 | chip->label, status); | |
981 | } | |
982 | ||
983 | static int __init gpiolib_sysfs_init(void) | |
984 | { | |
985 | int status; | |
986 | unsigned long flags; | |
987 | unsigned gpio; | |
988 | ||
ff77c352 DG |
989 | idr_init(&pdesc_idr); |
990 | ||
d8f388d8 DB |
991 | status = class_register(&gpio_class); |
992 | if (status < 0) | |
993 | return status; | |
994 | ||
995 | /* Scan and register the gpio_chips which registered very | |
996 | * early (e.g. before the class_register above was called). | |
997 | * | |
998 | * We run before arch_initcall() so chip->dev nodes can have | |
999 | * registered, and so arch_initcall() can always gpio_export(). | |
1000 | */ | |
1001 | spin_lock_irqsave(&gpio_lock, flags); | |
1002 | for (gpio = 0; gpio < ARCH_NR_GPIOS; gpio++) { | |
1003 | struct gpio_chip *chip; | |
1004 | ||
1005 | chip = gpio_desc[gpio].chip; | |
1006 | if (!chip || chip->exported) | |
1007 | continue; | |
1008 | ||
1009 | spin_unlock_irqrestore(&gpio_lock, flags); | |
1010 | status = gpiochip_export(chip); | |
1011 | spin_lock_irqsave(&gpio_lock, flags); | |
1012 | } | |
1013 | spin_unlock_irqrestore(&gpio_lock, flags); | |
1014 | ||
1015 | ||
1016 | return status; | |
1017 | } | |
1018 | postcore_initcall(gpiolib_sysfs_init); | |
1019 | ||
1020 | #else | |
1021 | static inline int gpiochip_export(struct gpio_chip *chip) | |
1022 | { | |
1023 | return 0; | |
1024 | } | |
1025 | ||
1026 | static inline void gpiochip_unexport(struct gpio_chip *chip) | |
1027 | { | |
1028 | } | |
1029 | ||
1030 | #endif /* CONFIG_GPIO_SYSFS */ | |
1031 | ||
d2876d08 DB |
1032 | /** |
1033 | * gpiochip_add() - register a gpio_chip | |
1034 | * @chip: the chip to register, with chip->base initialized | |
1035 | * Context: potentially before irqs or kmalloc will work | |
1036 | * | |
1037 | * Returns a negative errno if the chip can't be registered, such as | |
1038 | * because the chip->base is invalid or already associated with a | |
1039 | * different chip. Otherwise it returns zero as a success code. | |
8d0aab2f | 1040 | * |
d8f388d8 DB |
1041 | * When gpiochip_add() is called very early during boot, so that GPIOs |
1042 | * can be freely used, the chip->dev device must be registered before | |
1043 | * the gpio framework's arch_initcall(). Otherwise sysfs initialization | |
1044 | * for GPIOs will fail rudely. | |
1045 | * | |
8d0aab2f AV |
1046 | * If chip->base is negative, this requests dynamic assignment of |
1047 | * a range of valid GPIOs. | |
d2876d08 DB |
1048 | */ |
1049 | int gpiochip_add(struct gpio_chip *chip) | |
1050 | { | |
1051 | unsigned long flags; | |
1052 | int status = 0; | |
1053 | unsigned id; | |
8d0aab2f | 1054 | int base = chip->base; |
d2876d08 | 1055 | |
bff5fda9 | 1056 | if ((!gpio_is_valid(base) || !gpio_is_valid(base + chip->ngpio - 1)) |
8d0aab2f | 1057 | && base >= 0) { |
d2876d08 DB |
1058 | status = -EINVAL; |
1059 | goto fail; | |
1060 | } | |
1061 | ||
1062 | spin_lock_irqsave(&gpio_lock, flags); | |
1063 | ||
8d0aab2f AV |
1064 | if (base < 0) { |
1065 | base = gpiochip_find_base(chip->ngpio); | |
1066 | if (base < 0) { | |
1067 | status = base; | |
d8f388d8 | 1068 | goto unlock; |
8d0aab2f AV |
1069 | } |
1070 | chip->base = base; | |
1071 | } | |
1072 | ||
d2876d08 | 1073 | /* these GPIO numbers must not be managed by another gpio_chip */ |
8d0aab2f | 1074 | for (id = base; id < base + chip->ngpio; id++) { |
d2876d08 DB |
1075 | if (gpio_desc[id].chip != NULL) { |
1076 | status = -EBUSY; | |
1077 | break; | |
1078 | } | |
1079 | } | |
1080 | if (status == 0) { | |
8d0aab2f | 1081 | for (id = base; id < base + chip->ngpio; id++) { |
d2876d08 | 1082 | gpio_desc[id].chip = chip; |
d8f388d8 DB |
1083 | |
1084 | /* REVISIT: most hardware initializes GPIOs as | |
1085 | * inputs (often with pullups enabled) so power | |
1086 | * usage is minimized. Linux code should set the | |
1087 | * gpio direction first thing; but until it does, | |
1088 | * we may expose the wrong direction in sysfs. | |
1089 | */ | |
1090 | gpio_desc[id].flags = !chip->direction_input | |
1091 | ? (1 << FLAG_IS_OUT) | |
1092 | : 0; | |
d2876d08 DB |
1093 | } |
1094 | } | |
1095 | ||
d8f388d8 | 1096 | unlock: |
d2876d08 | 1097 | spin_unlock_irqrestore(&gpio_lock, flags); |
d8f388d8 DB |
1098 | if (status == 0) |
1099 | status = gpiochip_export(chip); | |
d2876d08 DB |
1100 | fail: |
1101 | /* failures here can mean systems won't boot... */ | |
1102 | if (status) | |
1103 | pr_err("gpiochip_add: gpios %d..%d (%s) not registered\n", | |
bff5fda9 | 1104 | chip->base, chip->base + chip->ngpio - 1, |
d2876d08 DB |
1105 | chip->label ? : "generic"); |
1106 | return status; | |
1107 | } | |
1108 | EXPORT_SYMBOL_GPL(gpiochip_add); | |
1109 | ||
1110 | /** | |
1111 | * gpiochip_remove() - unregister a gpio_chip | |
1112 | * @chip: the chip to unregister | |
1113 | * | |
1114 | * A gpio_chip with any GPIOs still requested may not be removed. | |
1115 | */ | |
1116 | int gpiochip_remove(struct gpio_chip *chip) | |
1117 | { | |
1118 | unsigned long flags; | |
1119 | int status = 0; | |
1120 | unsigned id; | |
1121 | ||
1122 | spin_lock_irqsave(&gpio_lock, flags); | |
1123 | ||
1124 | for (id = chip->base; id < chip->base + chip->ngpio; id++) { | |
1125 | if (test_bit(FLAG_REQUESTED, &gpio_desc[id].flags)) { | |
1126 | status = -EBUSY; | |
1127 | break; | |
1128 | } | |
1129 | } | |
1130 | if (status == 0) { | |
1131 | for (id = chip->base; id < chip->base + chip->ngpio; id++) | |
1132 | gpio_desc[id].chip = NULL; | |
1133 | } | |
1134 | ||
1135 | spin_unlock_irqrestore(&gpio_lock, flags); | |
d8f388d8 DB |
1136 | |
1137 | if (status == 0) | |
1138 | gpiochip_unexport(chip); | |
1139 | ||
d2876d08 DB |
1140 | return status; |
1141 | } | |
1142 | EXPORT_SYMBOL_GPL(gpiochip_remove); | |
1143 | ||
1144 | ||
1145 | /* These "optional" allocation calls help prevent drivers from stomping | |
1146 | * on each other, and help provide better diagnostics in debugfs. | |
1147 | * They're called even less than the "set direction" calls. | |
1148 | */ | |
1149 | int gpio_request(unsigned gpio, const char *label) | |
1150 | { | |
1151 | struct gpio_desc *desc; | |
35e8bb51 | 1152 | struct gpio_chip *chip; |
d2876d08 DB |
1153 | int status = -EINVAL; |
1154 | unsigned long flags; | |
1155 | ||
1156 | spin_lock_irqsave(&gpio_lock, flags); | |
1157 | ||
e6de1808 | 1158 | if (!gpio_is_valid(gpio)) |
d2876d08 DB |
1159 | goto done; |
1160 | desc = &gpio_desc[gpio]; | |
35e8bb51 DB |
1161 | chip = desc->chip; |
1162 | if (chip == NULL) | |
d2876d08 DB |
1163 | goto done; |
1164 | ||
35e8bb51 | 1165 | if (!try_module_get(chip->owner)) |
438d8908 GL |
1166 | goto done; |
1167 | ||
d2876d08 | 1168 | /* NOTE: gpio_request() can be called in early boot, |
35e8bb51 | 1169 | * before IRQs are enabled, for non-sleeping (SOC) GPIOs. |
d2876d08 DB |
1170 | */ |
1171 | ||
1172 | if (test_and_set_bit(FLAG_REQUESTED, &desc->flags) == 0) { | |
1173 | desc_set_label(desc, label ? : "?"); | |
1174 | status = 0; | |
438d8908 | 1175 | } else { |
d2876d08 | 1176 | status = -EBUSY; |
35e8bb51 | 1177 | module_put(chip->owner); |
7460db56 | 1178 | goto done; |
35e8bb51 DB |
1179 | } |
1180 | ||
1181 | if (chip->request) { | |
1182 | /* chip->request may sleep */ | |
1183 | spin_unlock_irqrestore(&gpio_lock, flags); | |
1184 | status = chip->request(chip, gpio - chip->base); | |
1185 | spin_lock_irqsave(&gpio_lock, flags); | |
1186 | ||
1187 | if (status < 0) { | |
1188 | desc_set_label(desc, NULL); | |
1189 | module_put(chip->owner); | |
1190 | clear_bit(FLAG_REQUESTED, &desc->flags); | |
1191 | } | |
438d8908 | 1192 | } |
d2876d08 DB |
1193 | |
1194 | done: | |
1195 | if (status) | |
1196 | pr_debug("gpio_request: gpio-%d (%s) status %d\n", | |
1197 | gpio, label ? : "?", status); | |
1198 | spin_unlock_irqrestore(&gpio_lock, flags); | |
1199 | return status; | |
1200 | } | |
1201 | EXPORT_SYMBOL_GPL(gpio_request); | |
1202 | ||
1203 | void gpio_free(unsigned gpio) | |
1204 | { | |
1205 | unsigned long flags; | |
1206 | struct gpio_desc *desc; | |
35e8bb51 | 1207 | struct gpio_chip *chip; |
d2876d08 | 1208 | |
3d599d1c UKK |
1209 | might_sleep(); |
1210 | ||
e6de1808 | 1211 | if (!gpio_is_valid(gpio)) { |
d2876d08 DB |
1212 | WARN_ON(extra_checks); |
1213 | return; | |
1214 | } | |
1215 | ||
d8f388d8 DB |
1216 | gpio_unexport(gpio); |
1217 | ||
d2876d08 DB |
1218 | spin_lock_irqsave(&gpio_lock, flags); |
1219 | ||
1220 | desc = &gpio_desc[gpio]; | |
35e8bb51 DB |
1221 | chip = desc->chip; |
1222 | if (chip && test_bit(FLAG_REQUESTED, &desc->flags)) { | |
1223 | if (chip->free) { | |
1224 | spin_unlock_irqrestore(&gpio_lock, flags); | |
1225 | might_sleep_if(extra_checks && chip->can_sleep); | |
1226 | chip->free(chip, gpio - chip->base); | |
1227 | spin_lock_irqsave(&gpio_lock, flags); | |
1228 | } | |
d2876d08 | 1229 | desc_set_label(desc, NULL); |
438d8908 | 1230 | module_put(desc->chip->owner); |
07697461 | 1231 | clear_bit(FLAG_ACTIVE_LOW, &desc->flags); |
35e8bb51 | 1232 | clear_bit(FLAG_REQUESTED, &desc->flags); |
438d8908 | 1233 | } else |
d2876d08 DB |
1234 | WARN_ON(extra_checks); |
1235 | ||
1236 | spin_unlock_irqrestore(&gpio_lock, flags); | |
1237 | } | |
1238 | EXPORT_SYMBOL_GPL(gpio_free); | |
1239 | ||
1240 | ||
1241 | /** | |
1242 | * gpiochip_is_requested - return string iff signal was requested | |
1243 | * @chip: controller managing the signal | |
1244 | * @offset: of signal within controller's 0..(ngpio - 1) range | |
1245 | * | |
1246 | * Returns NULL if the GPIO is not currently requested, else a string. | |
1247 | * If debugfs support is enabled, the string returned is the label passed | |
1248 | * to gpio_request(); otherwise it is a meaningless constant. | |
1249 | * | |
1250 | * This function is for use by GPIO controller drivers. The label can | |
1251 | * help with diagnostics, and knowing that the signal is used as a GPIO | |
1252 | * can help avoid accidentally multiplexing it to another controller. | |
1253 | */ | |
1254 | const char *gpiochip_is_requested(struct gpio_chip *chip, unsigned offset) | |
1255 | { | |
1256 | unsigned gpio = chip->base + offset; | |
1257 | ||
e6de1808 | 1258 | if (!gpio_is_valid(gpio) || gpio_desc[gpio].chip != chip) |
d2876d08 DB |
1259 | return NULL; |
1260 | if (test_bit(FLAG_REQUESTED, &gpio_desc[gpio].flags) == 0) | |
1261 | return NULL; | |
1262 | #ifdef CONFIG_DEBUG_FS | |
1263 | return gpio_desc[gpio].label; | |
1264 | #else | |
1265 | return "?"; | |
1266 | #endif | |
1267 | } | |
1268 | EXPORT_SYMBOL_GPL(gpiochip_is_requested); | |
1269 | ||
1270 | ||
1271 | /* Drivers MUST set GPIO direction before making get/set calls. In | |
1272 | * some cases this is done in early boot, before IRQs are enabled. | |
1273 | * | |
1274 | * As a rule these aren't called more than once (except for drivers | |
1275 | * using the open-drain emulation idiom) so these are natural places | |
1276 | * to accumulate extra debugging checks. Note that we can't (yet) | |
1277 | * rely on gpio_request() having been called beforehand. | |
1278 | */ | |
1279 | ||
1280 | int gpio_direction_input(unsigned gpio) | |
1281 | { | |
1282 | unsigned long flags; | |
1283 | struct gpio_chip *chip; | |
1284 | struct gpio_desc *desc = &gpio_desc[gpio]; | |
1285 | int status = -EINVAL; | |
1286 | ||
1287 | spin_lock_irqsave(&gpio_lock, flags); | |
1288 | ||
e6de1808 | 1289 | if (!gpio_is_valid(gpio)) |
d2876d08 DB |
1290 | goto fail; |
1291 | chip = desc->chip; | |
1292 | if (!chip || !chip->get || !chip->direction_input) | |
1293 | goto fail; | |
1294 | gpio -= chip->base; | |
1295 | if (gpio >= chip->ngpio) | |
1296 | goto fail; | |
35e8bb51 DB |
1297 | status = gpio_ensure_requested(desc, gpio); |
1298 | if (status < 0) | |
1299 | goto fail; | |
d2876d08 DB |
1300 | |
1301 | /* now we know the gpio is valid and chip won't vanish */ | |
1302 | ||
1303 | spin_unlock_irqrestore(&gpio_lock, flags); | |
1304 | ||
1305 | might_sleep_if(extra_checks && chip->can_sleep); | |
1306 | ||
35e8bb51 DB |
1307 | if (status) { |
1308 | status = chip->request(chip, gpio); | |
1309 | if (status < 0) { | |
1310 | pr_debug("GPIO-%d: chip request fail, %d\n", | |
1311 | chip->base + gpio, status); | |
1312 | /* and it's not available to anyone else ... | |
1313 | * gpio_request() is the fully clean solution. | |
1314 | */ | |
1315 | goto lose; | |
1316 | } | |
1317 | } | |
1318 | ||
d2876d08 DB |
1319 | status = chip->direction_input(chip, gpio); |
1320 | if (status == 0) | |
1321 | clear_bit(FLAG_IS_OUT, &desc->flags); | |
35e8bb51 | 1322 | lose: |
d2876d08 DB |
1323 | return status; |
1324 | fail: | |
1325 | spin_unlock_irqrestore(&gpio_lock, flags); | |
1326 | if (status) | |
1327 | pr_debug("%s: gpio-%d status %d\n", | |
145980a0 | 1328 | __func__, gpio, status); |
d2876d08 DB |
1329 | return status; |
1330 | } | |
1331 | EXPORT_SYMBOL_GPL(gpio_direction_input); | |
1332 | ||
1333 | int gpio_direction_output(unsigned gpio, int value) | |
1334 | { | |
1335 | unsigned long flags; | |
1336 | struct gpio_chip *chip; | |
1337 | struct gpio_desc *desc = &gpio_desc[gpio]; | |
1338 | int status = -EINVAL; | |
1339 | ||
1340 | spin_lock_irqsave(&gpio_lock, flags); | |
1341 | ||
e6de1808 | 1342 | if (!gpio_is_valid(gpio)) |
d2876d08 DB |
1343 | goto fail; |
1344 | chip = desc->chip; | |
1345 | if (!chip || !chip->set || !chip->direction_output) | |
1346 | goto fail; | |
1347 | gpio -= chip->base; | |
1348 | if (gpio >= chip->ngpio) | |
1349 | goto fail; | |
35e8bb51 DB |
1350 | status = gpio_ensure_requested(desc, gpio); |
1351 | if (status < 0) | |
1352 | goto fail; | |
d2876d08 DB |
1353 | |
1354 | /* now we know the gpio is valid and chip won't vanish */ | |
1355 | ||
1356 | spin_unlock_irqrestore(&gpio_lock, flags); | |
1357 | ||
1358 | might_sleep_if(extra_checks && chip->can_sleep); | |
1359 | ||
35e8bb51 DB |
1360 | if (status) { |
1361 | status = chip->request(chip, gpio); | |
1362 | if (status < 0) { | |
1363 | pr_debug("GPIO-%d: chip request fail, %d\n", | |
1364 | chip->base + gpio, status); | |
1365 | /* and it's not available to anyone else ... | |
1366 | * gpio_request() is the fully clean solution. | |
1367 | */ | |
1368 | goto lose; | |
1369 | } | |
1370 | } | |
1371 | ||
d2876d08 DB |
1372 | status = chip->direction_output(chip, gpio, value); |
1373 | if (status == 0) | |
1374 | set_bit(FLAG_IS_OUT, &desc->flags); | |
35e8bb51 | 1375 | lose: |
d2876d08 DB |
1376 | return status; |
1377 | fail: | |
1378 | spin_unlock_irqrestore(&gpio_lock, flags); | |
1379 | if (status) | |
1380 | pr_debug("%s: gpio-%d status %d\n", | |
145980a0 | 1381 | __func__, gpio, status); |
d2876d08 DB |
1382 | return status; |
1383 | } | |
1384 | EXPORT_SYMBOL_GPL(gpio_direction_output); | |
1385 | ||
1386 | ||
1387 | /* I/O calls are only valid after configuration completed; the relevant | |
1388 | * "is this a valid GPIO" error checks should already have been done. | |
1389 | * | |
1390 | * "Get" operations are often inlinable as reading a pin value register, | |
1391 | * and masking the relevant bit in that register. | |
1392 | * | |
1393 | * When "set" operations are inlinable, they involve writing that mask to | |
1394 | * one register to set a low value, or a different register to set it high. | |
1395 | * Otherwise locking is needed, so there may be little value to inlining. | |
1396 | * | |
1397 | *------------------------------------------------------------------------ | |
1398 | * | |
1399 | * IMPORTANT!!! The hot paths -- get/set value -- assume that callers | |
1400 | * have requested the GPIO. That can include implicit requesting by | |
1401 | * a direction setting call. Marking a gpio as requested locks its chip | |
1402 | * in memory, guaranteeing that these table lookups need no more locking | |
1403 | * and that gpiochip_remove() will fail. | |
1404 | * | |
1405 | * REVISIT when debugging, consider adding some instrumentation to ensure | |
1406 | * that the GPIO was actually requested. | |
1407 | */ | |
1408 | ||
1409 | /** | |
1410 | * __gpio_get_value() - return a gpio's value | |
1411 | * @gpio: gpio whose value will be returned | |
1412 | * Context: any | |
1413 | * | |
1414 | * This is used directly or indirectly to implement gpio_get_value(). | |
1415 | * It returns the zero or nonzero value provided by the associated | |
1416 | * gpio_chip.get() method; or zero if no such method is provided. | |
1417 | */ | |
1418 | int __gpio_get_value(unsigned gpio) | |
1419 | { | |
1420 | struct gpio_chip *chip; | |
1421 | ||
1422 | chip = gpio_to_chip(gpio); | |
1423 | WARN_ON(extra_checks && chip->can_sleep); | |
1424 | return chip->get ? chip->get(chip, gpio - chip->base) : 0; | |
1425 | } | |
1426 | EXPORT_SYMBOL_GPL(__gpio_get_value); | |
1427 | ||
1428 | /** | |
1429 | * __gpio_set_value() - assign a gpio's value | |
1430 | * @gpio: gpio whose value will be assigned | |
1431 | * @value: value to assign | |
1432 | * Context: any | |
1433 | * | |
1434 | * This is used directly or indirectly to implement gpio_set_value(). | |
1435 | * It invokes the associated gpio_chip.set() method. | |
1436 | */ | |
1437 | void __gpio_set_value(unsigned gpio, int value) | |
1438 | { | |
1439 | struct gpio_chip *chip; | |
1440 | ||
1441 | chip = gpio_to_chip(gpio); | |
1442 | WARN_ON(extra_checks && chip->can_sleep); | |
1443 | chip->set(chip, gpio - chip->base, value); | |
1444 | } | |
1445 | EXPORT_SYMBOL_GPL(__gpio_set_value); | |
1446 | ||
1447 | /** | |
1448 | * __gpio_cansleep() - report whether gpio value access will sleep | |
1449 | * @gpio: gpio in question | |
1450 | * Context: any | |
1451 | * | |
1452 | * This is used directly or indirectly to implement gpio_cansleep(). It | |
1453 | * returns nonzero if access reading or writing the GPIO value can sleep. | |
1454 | */ | |
1455 | int __gpio_cansleep(unsigned gpio) | |
1456 | { | |
1457 | struct gpio_chip *chip; | |
1458 | ||
1459 | /* only call this on GPIOs that are valid! */ | |
1460 | chip = gpio_to_chip(gpio); | |
1461 | ||
1462 | return chip->can_sleep; | |
1463 | } | |
1464 | EXPORT_SYMBOL_GPL(__gpio_cansleep); | |
1465 | ||
0f6d504e DB |
1466 | /** |
1467 | * __gpio_to_irq() - return the IRQ corresponding to a GPIO | |
1468 | * @gpio: gpio whose IRQ will be returned (already requested) | |
1469 | * Context: any | |
1470 | * | |
1471 | * This is used directly or indirectly to implement gpio_to_irq(). | |
1472 | * It returns the number of the IRQ signaled by this (input) GPIO, | |
1473 | * or a negative errno. | |
1474 | */ | |
1475 | int __gpio_to_irq(unsigned gpio) | |
1476 | { | |
1477 | struct gpio_chip *chip; | |
1478 | ||
1479 | chip = gpio_to_chip(gpio); | |
1480 | return chip->to_irq ? chip->to_irq(chip, gpio - chip->base) : -ENXIO; | |
1481 | } | |
1482 | EXPORT_SYMBOL_GPL(__gpio_to_irq); | |
1483 | ||
d2876d08 DB |
1484 | |
1485 | ||
1486 | /* There's no value in making it easy to inline GPIO calls that may sleep. | |
1487 | * Common examples include ones connected to I2C or SPI chips. | |
1488 | */ | |
1489 | ||
1490 | int gpio_get_value_cansleep(unsigned gpio) | |
1491 | { | |
1492 | struct gpio_chip *chip; | |
1493 | ||
1494 | might_sleep_if(extra_checks); | |
1495 | chip = gpio_to_chip(gpio); | |
978ccaa8 | 1496 | return chip->get ? chip->get(chip, gpio - chip->base) : 0; |
d2876d08 DB |
1497 | } |
1498 | EXPORT_SYMBOL_GPL(gpio_get_value_cansleep); | |
1499 | ||
1500 | void gpio_set_value_cansleep(unsigned gpio, int value) | |
1501 | { | |
1502 | struct gpio_chip *chip; | |
1503 | ||
1504 | might_sleep_if(extra_checks); | |
1505 | chip = gpio_to_chip(gpio); | |
1506 | chip->set(chip, gpio - chip->base, value); | |
1507 | } | |
1508 | EXPORT_SYMBOL_GPL(gpio_set_value_cansleep); | |
1509 | ||
1510 | ||
1511 | #ifdef CONFIG_DEBUG_FS | |
1512 | ||
d2876d08 DB |
1513 | static void gpiolib_dbg_show(struct seq_file *s, struct gpio_chip *chip) |
1514 | { | |
1515 | unsigned i; | |
1516 | unsigned gpio = chip->base; | |
1517 | struct gpio_desc *gdesc = &gpio_desc[gpio]; | |
1518 | int is_out; | |
1519 | ||
1520 | for (i = 0; i < chip->ngpio; i++, gpio++, gdesc++) { | |
1521 | if (!test_bit(FLAG_REQUESTED, &gdesc->flags)) | |
1522 | continue; | |
1523 | ||
1524 | is_out = test_bit(FLAG_IS_OUT, &gdesc->flags); | |
6e8ba729 | 1525 | seq_printf(s, " gpio-%-3d (%-20.20s) %s %s", |
d2876d08 DB |
1526 | gpio, gdesc->label, |
1527 | is_out ? "out" : "in ", | |
1528 | chip->get | |
1529 | ? (chip->get(chip, i) ? "hi" : "lo") | |
1530 | : "? "); | |
1531 | ||
1532 | if (!is_out) { | |
1533 | int irq = gpio_to_irq(gpio); | |
08678b08 | 1534 | struct irq_desc *desc = irq_to_desc(irq); |
d2876d08 DB |
1535 | |
1536 | /* This races with request_irq(), set_irq_type(), | |
1537 | * and set_irq_wake() ... but those are "rare". | |
1538 | * | |
1539 | * More significantly, trigger type flags aren't | |
1540 | * currently maintained by genirq. | |
1541 | */ | |
1542 | if (irq >= 0 && desc->action) { | |
1543 | char *trigger; | |
1544 | ||
1545 | switch (desc->status & IRQ_TYPE_SENSE_MASK) { | |
1546 | case IRQ_TYPE_NONE: | |
1547 | trigger = "(default)"; | |
1548 | break; | |
1549 | case IRQ_TYPE_EDGE_FALLING: | |
1550 | trigger = "edge-falling"; | |
1551 | break; | |
1552 | case IRQ_TYPE_EDGE_RISING: | |
1553 | trigger = "edge-rising"; | |
1554 | break; | |
1555 | case IRQ_TYPE_EDGE_BOTH: | |
1556 | trigger = "edge-both"; | |
1557 | break; | |
1558 | case IRQ_TYPE_LEVEL_HIGH: | |
1559 | trigger = "level-high"; | |
1560 | break; | |
1561 | case IRQ_TYPE_LEVEL_LOW: | |
1562 | trigger = "level-low"; | |
1563 | break; | |
1564 | default: | |
1565 | trigger = "?trigger?"; | |
1566 | break; | |
1567 | } | |
1568 | ||
1569 | seq_printf(s, " irq-%d %s%s", | |
1570 | irq, trigger, | |
1571 | (desc->status & IRQ_WAKEUP) | |
1572 | ? " wakeup" : ""); | |
1573 | } | |
1574 | } | |
1575 | ||
1576 | seq_printf(s, "\n"); | |
1577 | } | |
1578 | } | |
1579 | ||
1580 | static int gpiolib_show(struct seq_file *s, void *unused) | |
1581 | { | |
1582 | struct gpio_chip *chip = NULL; | |
1583 | unsigned gpio; | |
1584 | int started = 0; | |
1585 | ||
1586 | /* REVISIT this isn't locked against gpio_chip removal ... */ | |
1587 | ||
e6de1808 | 1588 | for (gpio = 0; gpio_is_valid(gpio); gpio++) { |
d8f388d8 DB |
1589 | struct device *dev; |
1590 | ||
d2876d08 DB |
1591 | if (chip == gpio_desc[gpio].chip) |
1592 | continue; | |
1593 | chip = gpio_desc[gpio].chip; | |
1594 | if (!chip) | |
1595 | continue; | |
1596 | ||
d8f388d8 | 1597 | seq_printf(s, "%sGPIOs %d-%d", |
d2876d08 | 1598 | started ? "\n" : "", |
d8f388d8 DB |
1599 | chip->base, chip->base + chip->ngpio - 1); |
1600 | dev = chip->dev; | |
1601 | if (dev) | |
1602 | seq_printf(s, ", %s/%s", | |
1603 | dev->bus ? dev->bus->name : "no-bus", | |
14ab309d | 1604 | dev_name(dev)); |
d8f388d8 DB |
1605 | if (chip->label) |
1606 | seq_printf(s, ", %s", chip->label); | |
1607 | if (chip->can_sleep) | |
1608 | seq_printf(s, ", can sleep"); | |
1609 | seq_printf(s, ":\n"); | |
1610 | ||
d2876d08 DB |
1611 | started = 1; |
1612 | if (chip->dbg_show) | |
1613 | chip->dbg_show(s, chip); | |
1614 | else | |
1615 | gpiolib_dbg_show(s, chip); | |
1616 | } | |
1617 | return 0; | |
1618 | } | |
1619 | ||
1620 | static int gpiolib_open(struct inode *inode, struct file *file) | |
1621 | { | |
1622 | return single_open(file, gpiolib_show, NULL); | |
1623 | } | |
1624 | ||
828c0950 | 1625 | static const struct file_operations gpiolib_operations = { |
d2876d08 DB |
1626 | .open = gpiolib_open, |
1627 | .read = seq_read, | |
1628 | .llseek = seq_lseek, | |
1629 | .release = single_release, | |
1630 | }; | |
1631 | ||
1632 | static int __init gpiolib_debugfs_init(void) | |
1633 | { | |
1634 | /* /sys/kernel/debug/gpio */ | |
1635 | (void) debugfs_create_file("gpio", S_IFREG | S_IRUGO, | |
1636 | NULL, NULL, &gpiolib_operations); | |
1637 | return 0; | |
1638 | } | |
1639 | subsys_initcall(gpiolib_debugfs_init); | |
1640 | ||
1641 | #endif /* DEBUG_FS */ |