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1 | #include <linux/kernel.h> | |
2 | #include <linux/module.h> | |
3 | #include <linux/interrupt.h> | |
4 | #include <linux/irq.h> | |
5 | #include <linux/spinlock.h> | |
6 | #include <linux/list.h> | |
7 | #include <linux/device.h> | |
8 | #include <linux/err.h> | |
9 | #include <linux/debugfs.h> | |
10 | #include <linux/seq_file.h> | |
11 | #include <linux/gpio.h> | |
12 | #include <linux/of_gpio.h> | |
13 | #include <linux/idr.h> | |
14 | #include <linux/slab.h> | |
15 | ||
16 | #define CREATE_TRACE_POINTS | |
17 | #include <trace/events/gpio.h> | |
18 | ||
19 | /* Optional implementation infrastructure for GPIO interfaces. | |
20 | * | |
21 | * Platforms may want to use this if they tend to use very many GPIOs | |
22 | * that aren't part of a System-On-Chip core; or across I2C/SPI/etc. | |
23 | * | |
24 | * When kernel footprint or instruction count is an issue, simpler | |
25 | * implementations may be preferred. The GPIO programming interface | |
26 | * allows for inlining speed-critical get/set operations for common | |
27 | * cases, so that access to SOC-integrated GPIOs can sometimes cost | |
28 | * only an instruction or two per bit. | |
29 | */ | |
30 | ||
31 | ||
32 | /* When debugging, extend minimal trust to callers and platform code. | |
33 | * Also emit diagnostic messages that may help initial bringup, when | |
34 | * board setup or driver bugs are most common. | |
35 | * | |
36 | * Otherwise, minimize overhead in what may be bitbanging codepaths. | |
37 | */ | |
38 | #ifdef DEBUG | |
39 | #define extra_checks 1 | |
40 | #else | |
41 | #define extra_checks 0 | |
42 | #endif | |
43 | ||
44 | /* gpio_lock prevents conflicts during gpio_desc[] table updates. | |
45 | * While any GPIO is requested, its gpio_chip is not removable; | |
46 | * each GPIO's "requested" flag serves as a lock and refcount. | |
47 | */ | |
48 | static DEFINE_SPINLOCK(gpio_lock); | |
49 | ||
50 | struct gpio_desc { | |
51 | struct gpio_chip *chip; | |
52 | unsigned long flags; | |
53 | /* flag symbols are bit numbers */ | |
54 | #define FLAG_REQUESTED 0 | |
55 | #define FLAG_IS_OUT 1 | |
56 | #define FLAG_EXPORT 2 /* protected by sysfs_lock */ | |
57 | #define FLAG_SYSFS 3 /* exported via /sys/class/gpio/control */ | |
58 | #define FLAG_TRIG_FALL 4 /* trigger on falling edge */ | |
59 | #define FLAG_TRIG_RISE 5 /* trigger on rising edge */ | |
60 | #define FLAG_ACTIVE_LOW 6 /* sysfs value has active low */ | |
61 | #define FLAG_OPEN_DRAIN 7 /* Gpio is open drain type */ | |
62 | #define FLAG_OPEN_SOURCE 8 /* Gpio is open source type */ | |
63 | ||
64 | #define ID_SHIFT 16 /* add new flags before this one */ | |
65 | ||
66 | #define GPIO_FLAGS_MASK ((1 << ID_SHIFT) - 1) | |
67 | #define GPIO_TRIGGER_MASK (BIT(FLAG_TRIG_FALL) | BIT(FLAG_TRIG_RISE)) | |
68 | ||
69 | #ifdef CONFIG_DEBUG_FS | |
70 | const char *label; | |
71 | #endif | |
72 | }; | |
73 | static struct gpio_desc gpio_desc[ARCH_NR_GPIOS]; | |
74 | ||
75 | #define GPIO_OFFSET_VALID(chip, offset) (offset >= 0 && offset < chip->ngpio) | |
76 | ||
77 | static LIST_HEAD(gpio_chips); | |
78 | ||
79 | #ifdef CONFIG_GPIO_SYSFS | |
80 | static DEFINE_IDR(dirent_idr); | |
81 | #endif | |
82 | ||
83 | /* | |
84 | * Internal gpiod_* API using descriptors instead of the integer namespace. | |
85 | * Most of this should eventually go public. | |
86 | */ | |
87 | static int gpiod_request(struct gpio_desc *desc, const char *label); | |
88 | static void gpiod_free(struct gpio_desc *desc); | |
89 | static int gpiod_direction_input(struct gpio_desc *desc); | |
90 | static int gpiod_direction_output(struct gpio_desc *desc, int value); | |
91 | static int gpiod_get_direction(const struct gpio_desc *desc); | |
92 | static int gpiod_set_debounce(struct gpio_desc *desc, unsigned debounce); | |
93 | static int gpiod_get_value_cansleep(const struct gpio_desc *desc); | |
94 | static void gpiod_set_value_cansleep(struct gpio_desc *desc, int value); | |
95 | static int gpiod_get_value(const struct gpio_desc *desc); | |
96 | static void gpiod_set_value(struct gpio_desc *desc, int value); | |
97 | static int gpiod_cansleep(const struct gpio_desc *desc); | |
98 | static int gpiod_to_irq(const struct gpio_desc *desc); | |
99 | static int gpiod_export(struct gpio_desc *desc, bool direction_may_change); | |
100 | static int gpiod_export_link(struct device *dev, const char *name, | |
101 | struct gpio_desc *desc); | |
102 | static int gpiod_sysfs_set_active_low(struct gpio_desc *desc, int value); | |
103 | static void gpiod_unexport(struct gpio_desc *desc); | |
104 | ||
105 | ||
106 | static inline void desc_set_label(struct gpio_desc *d, const char *label) | |
107 | { | |
108 | #ifdef CONFIG_DEBUG_FS | |
109 | d->label = label; | |
110 | #endif | |
111 | } | |
112 | ||
113 | /* | |
114 | * Return the GPIO number of the passed descriptor relative to its chip | |
115 | */ | |
116 | static int gpio_chip_hwgpio(const struct gpio_desc *desc) | |
117 | { | |
118 | return desc - &desc->chip->desc[0]; | |
119 | } | |
120 | ||
121 | /** | |
122 | * Convert a GPIO number to its descriptor | |
123 | */ | |
124 | static struct gpio_desc *gpio_to_desc(unsigned gpio) | |
125 | { | |
126 | if (WARN(!gpio_is_valid(gpio), "invalid GPIO %d\n", gpio)) | |
127 | return NULL; | |
128 | else | |
129 | return &gpio_desc[gpio]; | |
130 | } | |
131 | ||
132 | /** | |
133 | * Convert a GPIO descriptor to the integer namespace. | |
134 | * This should disappear in the future but is needed since we still | |
135 | * use GPIO numbers for error messages and sysfs nodes | |
136 | */ | |
137 | static int desc_to_gpio(const struct gpio_desc *desc) | |
138 | { | |
139 | return desc->chip->base + gpio_chip_hwgpio(desc); | |
140 | } | |
141 | ||
142 | ||
143 | /* Warn when drivers omit gpio_request() calls -- legal but ill-advised | |
144 | * when setting direction, and otherwise illegal. Until board setup code | |
145 | * and drivers use explicit requests everywhere (which won't happen when | |
146 | * those calls have no teeth) we can't avoid autorequesting. This nag | |
147 | * message should motivate switching to explicit requests... so should | |
148 | * the weaker cleanup after faults, compared to gpio_request(). | |
149 | * | |
150 | * NOTE: the autorequest mechanism is going away; at this point it's | |
151 | * only "legal" in the sense that (old) code using it won't break yet, | |
152 | * but instead only triggers a WARN() stack dump. | |
153 | */ | |
154 | static int gpio_ensure_requested(struct gpio_desc *desc) | |
155 | { | |
156 | const struct gpio_chip *chip = desc->chip; | |
157 | const int gpio = desc_to_gpio(desc); | |
158 | ||
159 | if (WARN(test_and_set_bit(FLAG_REQUESTED, &desc->flags) == 0, | |
160 | "autorequest GPIO-%d\n", gpio)) { | |
161 | if (!try_module_get(chip->owner)) { | |
162 | pr_err("GPIO-%d: module can't be gotten \n", gpio); | |
163 | clear_bit(FLAG_REQUESTED, &desc->flags); | |
164 | /* lose */ | |
165 | return -EIO; | |
166 | } | |
167 | desc_set_label(desc, "[auto]"); | |
168 | /* caller must chip->request() w/o spinlock */ | |
169 | if (chip->request) | |
170 | return 1; | |
171 | } | |
172 | return 0; | |
173 | } | |
174 | ||
175 | static struct gpio_chip *gpiod_to_chip(const struct gpio_desc *desc) | |
176 | { | |
177 | return desc ? desc->chip : NULL; | |
178 | } | |
179 | ||
180 | /* caller holds gpio_lock *OR* gpio is marked as requested */ | |
181 | struct gpio_chip *gpio_to_chip(unsigned gpio) | |
182 | { | |
183 | return gpiod_to_chip(gpio_to_desc(gpio)); | |
184 | } | |
185 | ||
186 | /* dynamic allocation of GPIOs, e.g. on a hotplugged device */ | |
187 | static int gpiochip_find_base(int ngpio) | |
188 | { | |
189 | struct gpio_chip *chip; | |
190 | int base = ARCH_NR_GPIOS - ngpio; | |
191 | ||
192 | list_for_each_entry_reverse(chip, &gpio_chips, list) { | |
193 | /* found a free space? */ | |
194 | if (chip->base + chip->ngpio <= base) | |
195 | break; | |
196 | else | |
197 | /* nope, check the space right before the chip */ | |
198 | base = chip->base - ngpio; | |
199 | } | |
200 | ||
201 | if (gpio_is_valid(base)) { | |
202 | pr_debug("%s: found new base at %d\n", __func__, base); | |
203 | return base; | |
204 | } else { | |
205 | pr_err("%s: cannot find free range\n", __func__); | |
206 | return -ENOSPC; | |
207 | } | |
208 | } | |
209 | ||
210 | /* caller ensures gpio is valid and requested, chip->get_direction may sleep */ | |
211 | static int gpiod_get_direction(const struct gpio_desc *desc) | |
212 | { | |
213 | struct gpio_chip *chip; | |
214 | unsigned offset; | |
215 | int status = -EINVAL; | |
216 | ||
217 | chip = gpiod_to_chip(desc); | |
218 | offset = gpio_chip_hwgpio(desc); | |
219 | ||
220 | if (!chip->get_direction) | |
221 | return status; | |
222 | ||
223 | status = chip->get_direction(chip, offset); | |
224 | if (status > 0) { | |
225 | /* GPIOF_DIR_IN, or other positive */ | |
226 | status = 1; | |
227 | /* FLAG_IS_OUT is just a cache of the result of get_direction(), | |
228 | * so it does not affect constness per se */ | |
229 | clear_bit(FLAG_IS_OUT, &((struct gpio_desc *)desc)->flags); | |
230 | } | |
231 | if (status == 0) { | |
232 | /* GPIOF_DIR_OUT */ | |
233 | set_bit(FLAG_IS_OUT, &((struct gpio_desc *)desc)->flags); | |
234 | } | |
235 | return status; | |
236 | } | |
237 | ||
238 | #ifdef CONFIG_GPIO_SYSFS | |
239 | ||
240 | /* lock protects against unexport_gpio() being called while | |
241 | * sysfs files are active. | |
242 | */ | |
243 | static DEFINE_MUTEX(sysfs_lock); | |
244 | ||
245 | /* | |
246 | * /sys/class/gpio/gpioN... only for GPIOs that are exported | |
247 | * /direction | |
248 | * * MAY BE OMITTED if kernel won't allow direction changes | |
249 | * * is read/write as "in" or "out" | |
250 | * * may also be written as "high" or "low", initializing | |
251 | * output value as specified ("out" implies "low") | |
252 | * /value | |
253 | * * always readable, subject to hardware behavior | |
254 | * * may be writable, as zero/nonzero | |
255 | * /edge | |
256 | * * configures behavior of poll(2) on /value | |
257 | * * available only if pin can generate IRQs on input | |
258 | * * is read/write as "none", "falling", "rising", or "both" | |
259 | * /active_low | |
260 | * * configures polarity of /value | |
261 | * * is read/write as zero/nonzero | |
262 | * * also affects existing and subsequent "falling" and "rising" | |
263 | * /edge configuration | |
264 | */ | |
265 | ||
266 | static ssize_t gpio_direction_show(struct device *dev, | |
267 | struct device_attribute *attr, char *buf) | |
268 | { | |
269 | const struct gpio_desc *desc = dev_get_drvdata(dev); | |
270 | ssize_t status; | |
271 | ||
272 | mutex_lock(&sysfs_lock); | |
273 | ||
274 | if (!test_bit(FLAG_EXPORT, &desc->flags)) { | |
275 | status = -EIO; | |
276 | } else { | |
277 | gpiod_get_direction(desc); | |
278 | status = sprintf(buf, "%s\n", | |
279 | test_bit(FLAG_IS_OUT, &desc->flags) | |
280 | ? "out" : "in"); | |
281 | } | |
282 | ||
283 | mutex_unlock(&sysfs_lock); | |
284 | return status; | |
285 | } | |
286 | ||
287 | static ssize_t gpio_direction_store(struct device *dev, | |
288 | struct device_attribute *attr, const char *buf, size_t size) | |
289 | { | |
290 | struct gpio_desc *desc = dev_get_drvdata(dev); | |
291 | ssize_t status; | |
292 | ||
293 | mutex_lock(&sysfs_lock); | |
294 | ||
295 | if (!test_bit(FLAG_EXPORT, &desc->flags)) | |
296 | status = -EIO; | |
297 | else if (sysfs_streq(buf, "high")) | |
298 | status = gpiod_direction_output(desc, 1); | |
299 | else if (sysfs_streq(buf, "out") || sysfs_streq(buf, "low")) | |
300 | status = gpiod_direction_output(desc, 0); | |
301 | else if (sysfs_streq(buf, "in")) | |
302 | status = gpiod_direction_input(desc); | |
303 | else | |
304 | status = -EINVAL; | |
305 | ||
306 | mutex_unlock(&sysfs_lock); | |
307 | return status ? : size; | |
308 | } | |
309 | ||
310 | static /* const */ DEVICE_ATTR(direction, 0644, | |
311 | gpio_direction_show, gpio_direction_store); | |
312 | ||
313 | static ssize_t gpio_value_show(struct device *dev, | |
314 | struct device_attribute *attr, char *buf) | |
315 | { | |
316 | struct gpio_desc *desc = dev_get_drvdata(dev); | |
317 | ssize_t status; | |
318 | ||
319 | mutex_lock(&sysfs_lock); | |
320 | ||
321 | if (!test_bit(FLAG_EXPORT, &desc->flags)) { | |
322 | status = -EIO; | |
323 | } else { | |
324 | int value; | |
325 | ||
326 | value = !!gpiod_get_value_cansleep(desc); | |
327 | if (test_bit(FLAG_ACTIVE_LOW, &desc->flags)) | |
328 | value = !value; | |
329 | ||
330 | status = sprintf(buf, "%d\n", value); | |
331 | } | |
332 | ||
333 | mutex_unlock(&sysfs_lock); | |
334 | return status; | |
335 | } | |
336 | ||
337 | static ssize_t gpio_value_store(struct device *dev, | |
338 | struct device_attribute *attr, const char *buf, size_t size) | |
339 | { | |
340 | struct gpio_desc *desc = dev_get_drvdata(dev); | |
341 | ssize_t status; | |
342 | ||
343 | mutex_lock(&sysfs_lock); | |
344 | ||
345 | if (!test_bit(FLAG_EXPORT, &desc->flags)) | |
346 | status = -EIO; | |
347 | else if (!test_bit(FLAG_IS_OUT, &desc->flags)) | |
348 | status = -EPERM; | |
349 | else { | |
350 | long value; | |
351 | ||
352 | status = kstrtol(buf, 0, &value); | |
353 | if (status == 0) { | |
354 | if (test_bit(FLAG_ACTIVE_LOW, &desc->flags)) | |
355 | value = !value; | |
356 | gpiod_set_value_cansleep(desc, value != 0); | |
357 | status = size; | |
358 | } | |
359 | } | |
360 | ||
361 | mutex_unlock(&sysfs_lock); | |
362 | return status; | |
363 | } | |
364 | ||
365 | static const DEVICE_ATTR(value, 0644, | |
366 | gpio_value_show, gpio_value_store); | |
367 | ||
368 | static irqreturn_t gpio_sysfs_irq(int irq, void *priv) | |
369 | { | |
370 | struct sysfs_dirent *value_sd = priv; | |
371 | ||
372 | sysfs_notify_dirent(value_sd); | |
373 | return IRQ_HANDLED; | |
374 | } | |
375 | ||
376 | static int gpio_setup_irq(struct gpio_desc *desc, struct device *dev, | |
377 | unsigned long gpio_flags) | |
378 | { | |
379 | struct sysfs_dirent *value_sd; | |
380 | unsigned long irq_flags; | |
381 | int ret, irq, id; | |
382 | ||
383 | if ((desc->flags & GPIO_TRIGGER_MASK) == gpio_flags) | |
384 | return 0; | |
385 | ||
386 | irq = gpiod_to_irq(desc); | |
387 | if (irq < 0) | |
388 | return -EIO; | |
389 | ||
390 | id = desc->flags >> ID_SHIFT; | |
391 | value_sd = idr_find(&dirent_idr, id); | |
392 | if (value_sd) | |
393 | free_irq(irq, value_sd); | |
394 | ||
395 | desc->flags &= ~GPIO_TRIGGER_MASK; | |
396 | ||
397 | if (!gpio_flags) { | |
398 | ret = 0; | |
399 | goto free_id; | |
400 | } | |
401 | ||
402 | irq_flags = IRQF_SHARED; | |
403 | if (test_bit(FLAG_TRIG_FALL, &gpio_flags)) | |
404 | irq_flags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ? | |
405 | IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING; | |
406 | if (test_bit(FLAG_TRIG_RISE, &gpio_flags)) | |
407 | irq_flags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ? | |
408 | IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING; | |
409 | ||
410 | if (!value_sd) { | |
411 | value_sd = sysfs_get_dirent(dev->kobj.sd, NULL, "value"); | |
412 | if (!value_sd) { | |
413 | ret = -ENODEV; | |
414 | goto err_out; | |
415 | } | |
416 | ||
417 | ret = idr_alloc(&dirent_idr, value_sd, 1, 0, GFP_KERNEL); | |
418 | if (ret < 0) | |
419 | goto free_sd; | |
420 | id = ret; | |
421 | ||
422 | desc->flags &= GPIO_FLAGS_MASK; | |
423 | desc->flags |= (unsigned long)id << ID_SHIFT; | |
424 | ||
425 | if (desc->flags >> ID_SHIFT != id) { | |
426 | ret = -ERANGE; | |
427 | goto free_id; | |
428 | } | |
429 | } | |
430 | ||
431 | ret = request_any_context_irq(irq, gpio_sysfs_irq, irq_flags, | |
432 | "gpiolib", value_sd); | |
433 | if (ret < 0) | |
434 | goto free_id; | |
435 | ||
436 | desc->flags |= gpio_flags; | |
437 | return 0; | |
438 | ||
439 | free_id: | |
440 | idr_remove(&dirent_idr, id); | |
441 | desc->flags &= GPIO_FLAGS_MASK; | |
442 | free_sd: | |
443 | if (value_sd) | |
444 | sysfs_put(value_sd); | |
445 | err_out: | |
446 | return ret; | |
447 | } | |
448 | ||
449 | static const struct { | |
450 | const char *name; | |
451 | unsigned long flags; | |
452 | } trigger_types[] = { | |
453 | { "none", 0 }, | |
454 | { "falling", BIT(FLAG_TRIG_FALL) }, | |
455 | { "rising", BIT(FLAG_TRIG_RISE) }, | |
456 | { "both", BIT(FLAG_TRIG_FALL) | BIT(FLAG_TRIG_RISE) }, | |
457 | }; | |
458 | ||
459 | static ssize_t gpio_edge_show(struct device *dev, | |
460 | struct device_attribute *attr, char *buf) | |
461 | { | |
462 | const struct gpio_desc *desc = dev_get_drvdata(dev); | |
463 | ssize_t status; | |
464 | ||
465 | mutex_lock(&sysfs_lock); | |
466 | ||
467 | if (!test_bit(FLAG_EXPORT, &desc->flags)) | |
468 | status = -EIO; | |
469 | else { | |
470 | int i; | |
471 | ||
472 | status = 0; | |
473 | for (i = 0; i < ARRAY_SIZE(trigger_types); i++) | |
474 | if ((desc->flags & GPIO_TRIGGER_MASK) | |
475 | == trigger_types[i].flags) { | |
476 | status = sprintf(buf, "%s\n", | |
477 | trigger_types[i].name); | |
478 | break; | |
479 | } | |
480 | } | |
481 | ||
482 | mutex_unlock(&sysfs_lock); | |
483 | return status; | |
484 | } | |
485 | ||
486 | static ssize_t gpio_edge_store(struct device *dev, | |
487 | struct device_attribute *attr, const char *buf, size_t size) | |
488 | { | |
489 | struct gpio_desc *desc = dev_get_drvdata(dev); | |
490 | ssize_t status; | |
491 | int i; | |
492 | ||
493 | for (i = 0; i < ARRAY_SIZE(trigger_types); i++) | |
494 | if (sysfs_streq(trigger_types[i].name, buf)) | |
495 | goto found; | |
496 | return -EINVAL; | |
497 | ||
498 | found: | |
499 | mutex_lock(&sysfs_lock); | |
500 | ||
501 | if (!test_bit(FLAG_EXPORT, &desc->flags)) | |
502 | status = -EIO; | |
503 | else { | |
504 | status = gpio_setup_irq(desc, dev, trigger_types[i].flags); | |
505 | if (!status) | |
506 | status = size; | |
507 | } | |
508 | ||
509 | mutex_unlock(&sysfs_lock); | |
510 | ||
511 | return status; | |
512 | } | |
513 | ||
514 | static DEVICE_ATTR(edge, 0644, gpio_edge_show, gpio_edge_store); | |
515 | ||
516 | static int sysfs_set_active_low(struct gpio_desc *desc, struct device *dev, | |
517 | int value) | |
518 | { | |
519 | int status = 0; | |
520 | ||
521 | if (!!test_bit(FLAG_ACTIVE_LOW, &desc->flags) == !!value) | |
522 | return 0; | |
523 | ||
524 | if (value) | |
525 | set_bit(FLAG_ACTIVE_LOW, &desc->flags); | |
526 | else | |
527 | clear_bit(FLAG_ACTIVE_LOW, &desc->flags); | |
528 | ||
529 | /* reconfigure poll(2) support if enabled on one edge only */ | |
530 | if (dev != NULL && (!!test_bit(FLAG_TRIG_RISE, &desc->flags) ^ | |
531 | !!test_bit(FLAG_TRIG_FALL, &desc->flags))) { | |
532 | unsigned long trigger_flags = desc->flags & GPIO_TRIGGER_MASK; | |
533 | ||
534 | gpio_setup_irq(desc, dev, 0); | |
535 | status = gpio_setup_irq(desc, dev, trigger_flags); | |
536 | } | |
537 | ||
538 | return status; | |
539 | } | |
540 | ||
541 | static ssize_t gpio_active_low_show(struct device *dev, | |
542 | struct device_attribute *attr, char *buf) | |
543 | { | |
544 | const struct gpio_desc *desc = dev_get_drvdata(dev); | |
545 | ssize_t status; | |
546 | ||
547 | mutex_lock(&sysfs_lock); | |
548 | ||
549 | if (!test_bit(FLAG_EXPORT, &desc->flags)) | |
550 | status = -EIO; | |
551 | else | |
552 | status = sprintf(buf, "%d\n", | |
553 | !!test_bit(FLAG_ACTIVE_LOW, &desc->flags)); | |
554 | ||
555 | mutex_unlock(&sysfs_lock); | |
556 | ||
557 | return status; | |
558 | } | |
559 | ||
560 | static ssize_t gpio_active_low_store(struct device *dev, | |
561 | struct device_attribute *attr, const char *buf, size_t size) | |
562 | { | |
563 | struct gpio_desc *desc = dev_get_drvdata(dev); | |
564 | ssize_t status; | |
565 | ||
566 | mutex_lock(&sysfs_lock); | |
567 | ||
568 | if (!test_bit(FLAG_EXPORT, &desc->flags)) { | |
569 | status = -EIO; | |
570 | } else { | |
571 | long value; | |
572 | ||
573 | status = kstrtol(buf, 0, &value); | |
574 | if (status == 0) | |
575 | status = sysfs_set_active_low(desc, dev, value != 0); | |
576 | } | |
577 | ||
578 | mutex_unlock(&sysfs_lock); | |
579 | ||
580 | return status ? : size; | |
581 | } | |
582 | ||
583 | static const DEVICE_ATTR(active_low, 0644, | |
584 | gpio_active_low_show, gpio_active_low_store); | |
585 | ||
586 | static const struct attribute *gpio_attrs[] = { | |
587 | &dev_attr_value.attr, | |
588 | &dev_attr_active_low.attr, | |
589 | NULL, | |
590 | }; | |
591 | ||
592 | static const struct attribute_group gpio_attr_group = { | |
593 | .attrs = (struct attribute **) gpio_attrs, | |
594 | }; | |
595 | ||
596 | /* | |
597 | * /sys/class/gpio/gpiochipN/ | |
598 | * /base ... matching gpio_chip.base (N) | |
599 | * /label ... matching gpio_chip.label | |
600 | * /ngpio ... matching gpio_chip.ngpio | |
601 | */ | |
602 | ||
603 | static ssize_t chip_base_show(struct device *dev, | |
604 | struct device_attribute *attr, char *buf) | |
605 | { | |
606 | const struct gpio_chip *chip = dev_get_drvdata(dev); | |
607 | ||
608 | return sprintf(buf, "%d\n", chip->base); | |
609 | } | |
610 | static DEVICE_ATTR(base, 0444, chip_base_show, NULL); | |
611 | ||
612 | static ssize_t chip_label_show(struct device *dev, | |
613 | struct device_attribute *attr, char *buf) | |
614 | { | |
615 | const struct gpio_chip *chip = dev_get_drvdata(dev); | |
616 | ||
617 | return sprintf(buf, "%s\n", chip->label ? : ""); | |
618 | } | |
619 | static DEVICE_ATTR(label, 0444, chip_label_show, NULL); | |
620 | ||
621 | static ssize_t chip_ngpio_show(struct device *dev, | |
622 | struct device_attribute *attr, char *buf) | |
623 | { | |
624 | const struct gpio_chip *chip = dev_get_drvdata(dev); | |
625 | ||
626 | return sprintf(buf, "%u\n", chip->ngpio); | |
627 | } | |
628 | static DEVICE_ATTR(ngpio, 0444, chip_ngpio_show, NULL); | |
629 | ||
630 | static const struct attribute *gpiochip_attrs[] = { | |
631 | &dev_attr_base.attr, | |
632 | &dev_attr_label.attr, | |
633 | &dev_attr_ngpio.attr, | |
634 | NULL, | |
635 | }; | |
636 | ||
637 | static const struct attribute_group gpiochip_attr_group = { | |
638 | .attrs = (struct attribute **) gpiochip_attrs, | |
639 | }; | |
640 | ||
641 | /* | |
642 | * /sys/class/gpio/export ... write-only | |
643 | * integer N ... number of GPIO to export (full access) | |
644 | * /sys/class/gpio/unexport ... write-only | |
645 | * integer N ... number of GPIO to unexport | |
646 | */ | |
647 | static ssize_t export_store(struct class *class, | |
648 | struct class_attribute *attr, | |
649 | const char *buf, size_t len) | |
650 | { | |
651 | long gpio; | |
652 | struct gpio_desc *desc; | |
653 | int status; | |
654 | ||
655 | status = kstrtol(buf, 0, &gpio); | |
656 | if (status < 0) | |
657 | goto done; | |
658 | ||
659 | desc = gpio_to_desc(gpio); | |
660 | /* reject invalid GPIOs */ | |
661 | if (!desc) { | |
662 | pr_warn("%s: invalid GPIO %ld\n", __func__, gpio); | |
663 | return -EINVAL; | |
664 | } | |
665 | ||
666 | /* No extra locking here; FLAG_SYSFS just signifies that the | |
667 | * request and export were done by on behalf of userspace, so | |
668 | * they may be undone on its behalf too. | |
669 | */ | |
670 | ||
671 | status = gpiod_request(desc, "sysfs"); | |
672 | if (status < 0) { | |
673 | if (status == -EPROBE_DEFER) | |
674 | status = -ENODEV; | |
675 | goto done; | |
676 | } | |
677 | status = gpiod_export(desc, true); | |
678 | if (status < 0) | |
679 | gpiod_free(desc); | |
680 | else | |
681 | set_bit(FLAG_SYSFS, &desc->flags); | |
682 | ||
683 | done: | |
684 | if (status) | |
685 | pr_debug("%s: status %d\n", __func__, status); | |
686 | return status ? : len; | |
687 | } | |
688 | ||
689 | static ssize_t unexport_store(struct class *class, | |
690 | struct class_attribute *attr, | |
691 | const char *buf, size_t len) | |
692 | { | |
693 | long gpio; | |
694 | struct gpio_desc *desc; | |
695 | int status; | |
696 | ||
697 | status = kstrtol(buf, 0, &gpio); | |
698 | if (status < 0) | |
699 | goto done; | |
700 | ||
701 | desc = gpio_to_desc(gpio); | |
702 | /* reject bogus commands (gpio_unexport ignores them) */ | |
703 | if (!desc) { | |
704 | pr_warn("%s: invalid GPIO %ld\n", __func__, gpio); | |
705 | return -EINVAL; | |
706 | } | |
707 | ||
708 | status = -EINVAL; | |
709 | ||
710 | /* No extra locking here; FLAG_SYSFS just signifies that the | |
711 | * request and export were done by on behalf of userspace, so | |
712 | * they may be undone on its behalf too. | |
713 | */ | |
714 | if (test_and_clear_bit(FLAG_SYSFS, &desc->flags)) { | |
715 | status = 0; | |
716 | gpiod_free(desc); | |
717 | } | |
718 | done: | |
719 | if (status) | |
720 | pr_debug("%s: status %d\n", __func__, status); | |
721 | return status ? : len; | |
722 | } | |
723 | ||
724 | static struct class_attribute gpio_class_attrs[] = { | |
725 | __ATTR(export, 0200, NULL, export_store), | |
726 | __ATTR(unexport, 0200, NULL, unexport_store), | |
727 | __ATTR_NULL, | |
728 | }; | |
729 | ||
730 | static struct class gpio_class = { | |
731 | .name = "gpio", | |
732 | .owner = THIS_MODULE, | |
733 | ||
734 | .class_attrs = gpio_class_attrs, | |
735 | }; | |
736 | ||
737 | ||
738 | /** | |
739 | * gpio_export - export a GPIO through sysfs | |
740 | * @gpio: gpio to make available, already requested | |
741 | * @direction_may_change: true if userspace may change gpio direction | |
742 | * Context: arch_initcall or later | |
743 | * | |
744 | * When drivers want to make a GPIO accessible to userspace after they | |
745 | * have requested it -- perhaps while debugging, or as part of their | |
746 | * public interface -- they may use this routine. If the GPIO can | |
747 | * change direction (some can't) and the caller allows it, userspace | |
748 | * will see "direction" sysfs attribute which may be used to change | |
749 | * the gpio's direction. A "value" attribute will always be provided. | |
750 | * | |
751 | * Returns zero on success, else an error. | |
752 | */ | |
753 | static int gpiod_export(struct gpio_desc *desc, bool direction_may_change) | |
754 | { | |
755 | unsigned long flags; | |
756 | int status; | |
757 | const char *ioname = NULL; | |
758 | struct device *dev; | |
759 | int offset; | |
760 | ||
761 | /* can't export until sysfs is available ... */ | |
762 | if (!gpio_class.p) { | |
763 | pr_debug("%s: called too early!\n", __func__); | |
764 | return -ENOENT; | |
765 | } | |
766 | ||
767 | if (!desc) { | |
768 | pr_debug("%s: invalid gpio descriptor\n", __func__); | |
769 | return -EINVAL; | |
770 | } | |
771 | ||
772 | mutex_lock(&sysfs_lock); | |
773 | ||
774 | spin_lock_irqsave(&gpio_lock, flags); | |
775 | if (!test_bit(FLAG_REQUESTED, &desc->flags) || | |
776 | test_bit(FLAG_EXPORT, &desc->flags)) { | |
777 | spin_unlock_irqrestore(&gpio_lock, flags); | |
778 | pr_debug("%s: gpio %d unavailable (requested=%d, exported=%d)\n", | |
779 | __func__, desc_to_gpio(desc), | |
780 | test_bit(FLAG_REQUESTED, &desc->flags), | |
781 | test_bit(FLAG_EXPORT, &desc->flags)); | |
782 | status = -EPERM; | |
783 | goto fail_unlock; | |
784 | } | |
785 | ||
786 | if (!desc->chip->direction_input || !desc->chip->direction_output) | |
787 | direction_may_change = false; | |
788 | spin_unlock_irqrestore(&gpio_lock, flags); | |
789 | ||
790 | offset = gpio_chip_hwgpio(desc); | |
791 | if (desc->chip->names && desc->chip->names[offset]) | |
792 | ioname = desc->chip->names[offset]; | |
793 | ||
794 | dev = device_create(&gpio_class, desc->chip->dev, MKDEV(0, 0), | |
795 | desc, ioname ? ioname : "gpio%u", | |
796 | desc_to_gpio(desc)); | |
797 | if (IS_ERR(dev)) { | |
798 | status = PTR_ERR(dev); | |
799 | goto fail_unlock; | |
800 | } | |
801 | ||
802 | status = sysfs_create_group(&dev->kobj, &gpio_attr_group); | |
803 | if (status) | |
804 | goto fail_unregister_device; | |
805 | ||
806 | if (direction_may_change) { | |
807 | status = device_create_file(dev, &dev_attr_direction); | |
808 | if (status) | |
809 | goto fail_unregister_device; | |
810 | } | |
811 | ||
812 | if (gpiod_to_irq(desc) >= 0 && (direction_may_change || | |
813 | !test_bit(FLAG_IS_OUT, &desc->flags))) { | |
814 | status = device_create_file(dev, &dev_attr_edge); | |
815 | if (status) | |
816 | goto fail_unregister_device; | |
817 | } | |
818 | ||
819 | set_bit(FLAG_EXPORT, &desc->flags); | |
820 | mutex_unlock(&sysfs_lock); | |
821 | return 0; | |
822 | ||
823 | fail_unregister_device: | |
824 | device_unregister(dev); | |
825 | fail_unlock: | |
826 | mutex_unlock(&sysfs_lock); | |
827 | pr_debug("%s: gpio%d status %d\n", __func__, desc_to_gpio(desc), | |
828 | status); | |
829 | return status; | |
830 | } | |
831 | ||
832 | int gpio_export(unsigned gpio, bool direction_may_change) | |
833 | { | |
834 | return gpiod_export(gpio_to_desc(gpio), direction_may_change); | |
835 | } | |
836 | EXPORT_SYMBOL_GPL(gpio_export); | |
837 | ||
838 | static int match_export(struct device *dev, const void *data) | |
839 | { | |
840 | return dev_get_drvdata(dev) == data; | |
841 | } | |
842 | ||
843 | /** | |
844 | * gpio_export_link - create a sysfs link to an exported GPIO node | |
845 | * @dev: device under which to create symlink | |
846 | * @name: name of the symlink | |
847 | * @gpio: gpio to create symlink to, already exported | |
848 | * | |
849 | * Set up a symlink from /sys/.../dev/name to /sys/class/gpio/gpioN | |
850 | * node. Caller is responsible for unlinking. | |
851 | * | |
852 | * Returns zero on success, else an error. | |
853 | */ | |
854 | static int gpiod_export_link(struct device *dev, const char *name, | |
855 | struct gpio_desc *desc) | |
856 | { | |
857 | int status = -EINVAL; | |
858 | ||
859 | if (!desc) { | |
860 | pr_warn("%s: invalid GPIO\n", __func__); | |
861 | return -EINVAL; | |
862 | } | |
863 | ||
864 | mutex_lock(&sysfs_lock); | |
865 | ||
866 | if (test_bit(FLAG_EXPORT, &desc->flags)) { | |
867 | struct device *tdev; | |
868 | ||
869 | tdev = class_find_device(&gpio_class, NULL, desc, match_export); | |
870 | if (tdev != NULL) { | |
871 | status = sysfs_create_link(&dev->kobj, &tdev->kobj, | |
872 | name); | |
873 | } else { | |
874 | status = -ENODEV; | |
875 | } | |
876 | } | |
877 | ||
878 | mutex_unlock(&sysfs_lock); | |
879 | ||
880 | if (status) | |
881 | pr_debug("%s: gpio%d status %d\n", __func__, desc_to_gpio(desc), | |
882 | status); | |
883 | ||
884 | return status; | |
885 | } | |
886 | ||
887 | int gpio_export_link(struct device *dev, const char *name, unsigned gpio) | |
888 | { | |
889 | return gpiod_export_link(dev, name, gpio_to_desc(gpio)); | |
890 | } | |
891 | EXPORT_SYMBOL_GPL(gpio_export_link); | |
892 | ||
893 | /** | |
894 | * gpio_sysfs_set_active_low - set the polarity of gpio sysfs value | |
895 | * @gpio: gpio to change | |
896 | * @value: non-zero to use active low, i.e. inverted values | |
897 | * | |
898 | * Set the polarity of /sys/class/gpio/gpioN/value sysfs attribute. | |
899 | * The GPIO does not have to be exported yet. If poll(2) support has | |
900 | * been enabled for either rising or falling edge, it will be | |
901 | * reconfigured to follow the new polarity. | |
902 | * | |
903 | * Returns zero on success, else an error. | |
904 | */ | |
905 | static int gpiod_sysfs_set_active_low(struct gpio_desc *desc, int value) | |
906 | { | |
907 | struct device *dev = NULL; | |
908 | int status = -EINVAL; | |
909 | ||
910 | if (!desc) { | |
911 | pr_warn("%s: invalid GPIO\n", __func__); | |
912 | return -EINVAL; | |
913 | } | |
914 | ||
915 | mutex_lock(&sysfs_lock); | |
916 | ||
917 | if (test_bit(FLAG_EXPORT, &desc->flags)) { | |
918 | dev = class_find_device(&gpio_class, NULL, desc, match_export); | |
919 | if (dev == NULL) { | |
920 | status = -ENODEV; | |
921 | goto unlock; | |
922 | } | |
923 | } | |
924 | ||
925 | status = sysfs_set_active_low(desc, dev, value); | |
926 | ||
927 | unlock: | |
928 | mutex_unlock(&sysfs_lock); | |
929 | ||
930 | if (status) | |
931 | pr_debug("%s: gpio%d status %d\n", __func__, desc_to_gpio(desc), | |
932 | status); | |
933 | ||
934 | return status; | |
935 | } | |
936 | ||
937 | int gpio_sysfs_set_active_low(unsigned gpio, int value) | |
938 | { | |
939 | return gpiod_sysfs_set_active_low(gpio_to_desc(gpio), value); | |
940 | } | |
941 | EXPORT_SYMBOL_GPL(gpio_sysfs_set_active_low); | |
942 | ||
943 | /** | |
944 | * gpio_unexport - reverse effect of gpio_export() | |
945 | * @gpio: gpio to make unavailable | |
946 | * | |
947 | * This is implicit on gpio_free(). | |
948 | */ | |
949 | static void gpiod_unexport(struct gpio_desc *desc) | |
950 | { | |
951 | int status = 0; | |
952 | struct device *dev = NULL; | |
953 | ||
954 | if (!desc) { | |
955 | pr_warn("%s: invalid GPIO\n", __func__); | |
956 | return; | |
957 | } | |
958 | ||
959 | mutex_lock(&sysfs_lock); | |
960 | ||
961 | if (test_bit(FLAG_EXPORT, &desc->flags)) { | |
962 | ||
963 | dev = class_find_device(&gpio_class, NULL, desc, match_export); | |
964 | if (dev) { | |
965 | gpio_setup_irq(desc, dev, 0); | |
966 | clear_bit(FLAG_EXPORT, &desc->flags); | |
967 | } else | |
968 | status = -ENODEV; | |
969 | } | |
970 | ||
971 | mutex_unlock(&sysfs_lock); | |
972 | ||
973 | if (dev) { | |
974 | device_unregister(dev); | |
975 | put_device(dev); | |
976 | } | |
977 | ||
978 | if (status) | |
979 | pr_debug("%s: gpio%d status %d\n", __func__, desc_to_gpio(desc), | |
980 | status); | |
981 | } | |
982 | ||
983 | void gpio_unexport(unsigned gpio) | |
984 | { | |
985 | gpiod_unexport(gpio_to_desc(gpio)); | |
986 | } | |
987 | EXPORT_SYMBOL_GPL(gpio_unexport); | |
988 | ||
989 | static int gpiochip_export(struct gpio_chip *chip) | |
990 | { | |
991 | int status; | |
992 | struct device *dev; | |
993 | ||
994 | /* Many systems register gpio chips for SOC support very early, | |
995 | * before driver model support is available. In those cases we | |
996 | * export this later, in gpiolib_sysfs_init() ... here we just | |
997 | * verify that _some_ field of gpio_class got initialized. | |
998 | */ | |
999 | if (!gpio_class.p) | |
1000 | return 0; | |
1001 | ||
1002 | /* use chip->base for the ID; it's already known to be unique */ | |
1003 | mutex_lock(&sysfs_lock); | |
1004 | dev = device_create(&gpio_class, chip->dev, MKDEV(0, 0), chip, | |
1005 | "gpiochip%d", chip->base); | |
1006 | if (!IS_ERR(dev)) { | |
1007 | status = sysfs_create_group(&dev->kobj, | |
1008 | &gpiochip_attr_group); | |
1009 | } else | |
1010 | status = PTR_ERR(dev); | |
1011 | chip->exported = (status == 0); | |
1012 | mutex_unlock(&sysfs_lock); | |
1013 | ||
1014 | if (status) { | |
1015 | unsigned long flags; | |
1016 | unsigned gpio; | |
1017 | ||
1018 | spin_lock_irqsave(&gpio_lock, flags); | |
1019 | gpio = 0; | |
1020 | while (gpio < chip->ngpio) | |
1021 | chip->desc[gpio++].chip = NULL; | |
1022 | spin_unlock_irqrestore(&gpio_lock, flags); | |
1023 | ||
1024 | pr_debug("%s: chip %s status %d\n", __func__, | |
1025 | chip->label, status); | |
1026 | } | |
1027 | ||
1028 | return status; | |
1029 | } | |
1030 | ||
1031 | static void gpiochip_unexport(struct gpio_chip *chip) | |
1032 | { | |
1033 | int status; | |
1034 | struct device *dev; | |
1035 | ||
1036 | mutex_lock(&sysfs_lock); | |
1037 | dev = class_find_device(&gpio_class, NULL, chip, match_export); | |
1038 | if (dev) { | |
1039 | put_device(dev); | |
1040 | device_unregister(dev); | |
1041 | chip->exported = 0; | |
1042 | status = 0; | |
1043 | } else | |
1044 | status = -ENODEV; | |
1045 | mutex_unlock(&sysfs_lock); | |
1046 | ||
1047 | if (status) | |
1048 | pr_debug("%s: chip %s status %d\n", __func__, | |
1049 | chip->label, status); | |
1050 | } | |
1051 | ||
1052 | static int __init gpiolib_sysfs_init(void) | |
1053 | { | |
1054 | int status; | |
1055 | unsigned long flags; | |
1056 | struct gpio_chip *chip; | |
1057 | ||
1058 | status = class_register(&gpio_class); | |
1059 | if (status < 0) | |
1060 | return status; | |
1061 | ||
1062 | /* Scan and register the gpio_chips which registered very | |
1063 | * early (e.g. before the class_register above was called). | |
1064 | * | |
1065 | * We run before arch_initcall() so chip->dev nodes can have | |
1066 | * registered, and so arch_initcall() can always gpio_export(). | |
1067 | */ | |
1068 | spin_lock_irqsave(&gpio_lock, flags); | |
1069 | list_for_each_entry(chip, &gpio_chips, list) { | |
1070 | if (!chip || chip->exported) | |
1071 | continue; | |
1072 | ||
1073 | spin_unlock_irqrestore(&gpio_lock, flags); | |
1074 | status = gpiochip_export(chip); | |
1075 | spin_lock_irqsave(&gpio_lock, flags); | |
1076 | } | |
1077 | spin_unlock_irqrestore(&gpio_lock, flags); | |
1078 | ||
1079 | ||
1080 | return status; | |
1081 | } | |
1082 | postcore_initcall(gpiolib_sysfs_init); | |
1083 | ||
1084 | #else | |
1085 | static inline int gpiochip_export(struct gpio_chip *chip) | |
1086 | { | |
1087 | return 0; | |
1088 | } | |
1089 | ||
1090 | static inline void gpiochip_unexport(struct gpio_chip *chip) | |
1091 | { | |
1092 | } | |
1093 | ||
1094 | static inline int gpiod_export(struct gpio_desc *desc, | |
1095 | bool direction_may_change) | |
1096 | { | |
1097 | return -ENOSYS; | |
1098 | } | |
1099 | ||
1100 | static inline int gpiod_export_link(struct device *dev, const char *name, | |
1101 | struct gpio_desc *desc) | |
1102 | { | |
1103 | return -ENOSYS; | |
1104 | } | |
1105 | ||
1106 | static inline int gpiod_sysfs_set_active_low(struct gpio_desc *desc, int value) | |
1107 | { | |
1108 | return -ENOSYS; | |
1109 | } | |
1110 | ||
1111 | static inline void gpiod_unexport(struct gpio_desc *desc) | |
1112 | { | |
1113 | } | |
1114 | ||
1115 | #endif /* CONFIG_GPIO_SYSFS */ | |
1116 | ||
1117 | /* | |
1118 | * Add a new chip to the global chips list, keeping the list of chips sorted | |
1119 | * by base order. | |
1120 | * | |
1121 | * Return -EBUSY if the new chip overlaps with some other chip's integer | |
1122 | * space. | |
1123 | */ | |
1124 | static int gpiochip_add_to_list(struct gpio_chip *chip) | |
1125 | { | |
1126 | struct list_head *pos = &gpio_chips; | |
1127 | struct gpio_chip *_chip; | |
1128 | int err = 0; | |
1129 | ||
1130 | /* find where to insert our chip */ | |
1131 | list_for_each(pos, &gpio_chips) { | |
1132 | _chip = list_entry(pos, struct gpio_chip, list); | |
1133 | /* shall we insert before _chip? */ | |
1134 | if (_chip->base >= chip->base + chip->ngpio) | |
1135 | break; | |
1136 | } | |
1137 | ||
1138 | /* are we stepping on the chip right before? */ | |
1139 | if (pos != &gpio_chips && pos->prev != &gpio_chips) { | |
1140 | _chip = list_entry(pos->prev, struct gpio_chip, list); | |
1141 | if (_chip->base + _chip->ngpio > chip->base) { | |
1142 | dev_err(chip->dev, | |
1143 | "GPIO integer space overlap, cannot add chip\n"); | |
1144 | err = -EBUSY; | |
1145 | } | |
1146 | } | |
1147 | ||
1148 | if (!err) | |
1149 | list_add_tail(&chip->list, pos); | |
1150 | ||
1151 | return err; | |
1152 | } | |
1153 | ||
1154 | /** | |
1155 | * gpiochip_add() - register a gpio_chip | |
1156 | * @chip: the chip to register, with chip->base initialized | |
1157 | * Context: potentially before irqs or kmalloc will work | |
1158 | * | |
1159 | * Returns a negative errno if the chip can't be registered, such as | |
1160 | * because the chip->base is invalid or already associated with a | |
1161 | * different chip. Otherwise it returns zero as a success code. | |
1162 | * | |
1163 | * When gpiochip_add() is called very early during boot, so that GPIOs | |
1164 | * can be freely used, the chip->dev device must be registered before | |
1165 | * the gpio framework's arch_initcall(). Otherwise sysfs initialization | |
1166 | * for GPIOs will fail rudely. | |
1167 | * | |
1168 | * If chip->base is negative, this requests dynamic assignment of | |
1169 | * a range of valid GPIOs. | |
1170 | */ | |
1171 | int gpiochip_add(struct gpio_chip *chip) | |
1172 | { | |
1173 | unsigned long flags; | |
1174 | int status = 0; | |
1175 | unsigned id; | |
1176 | int base = chip->base; | |
1177 | ||
1178 | if ((!gpio_is_valid(base) || !gpio_is_valid(base + chip->ngpio - 1)) | |
1179 | && base >= 0) { | |
1180 | status = -EINVAL; | |
1181 | goto fail; | |
1182 | } | |
1183 | ||
1184 | spin_lock_irqsave(&gpio_lock, flags); | |
1185 | ||
1186 | if (base < 0) { | |
1187 | base = gpiochip_find_base(chip->ngpio); | |
1188 | if (base < 0) { | |
1189 | status = base; | |
1190 | goto unlock; | |
1191 | } | |
1192 | chip->base = base; | |
1193 | } | |
1194 | ||
1195 | status = gpiochip_add_to_list(chip); | |
1196 | ||
1197 | if (status == 0) { | |
1198 | chip->desc = &gpio_desc[chip->base]; | |
1199 | ||
1200 | for (id = 0; id < chip->ngpio; id++) { | |
1201 | struct gpio_desc *desc = &chip->desc[id]; | |
1202 | desc->chip = chip; | |
1203 | ||
1204 | /* REVISIT: most hardware initializes GPIOs as | |
1205 | * inputs (often with pullups enabled) so power | |
1206 | * usage is minimized. Linux code should set the | |
1207 | * gpio direction first thing; but until it does, | |
1208 | * and in case chip->get_direction is not set, | |
1209 | * we may expose the wrong direction in sysfs. | |
1210 | */ | |
1211 | desc->flags = !chip->direction_input | |
1212 | ? (1 << FLAG_IS_OUT) | |
1213 | : 0; | |
1214 | } | |
1215 | } | |
1216 | ||
1217 | spin_unlock_irqrestore(&gpio_lock, flags); | |
1218 | ||
1219 | #ifdef CONFIG_PINCTRL | |
1220 | INIT_LIST_HEAD(&chip->pin_ranges); | |
1221 | #endif | |
1222 | ||
1223 | of_gpiochip_add(chip); | |
1224 | ||
1225 | if (status) | |
1226 | goto fail; | |
1227 | ||
1228 | status = gpiochip_export(chip); | |
1229 | if (status) | |
1230 | goto fail; | |
1231 | ||
1232 | pr_debug("gpiochip_add: registered GPIOs %d to %d on device: %s\n", | |
1233 | chip->base, chip->base + chip->ngpio - 1, | |
1234 | chip->label ? : "generic"); | |
1235 | ||
1236 | return 0; | |
1237 | ||
1238 | unlock: | |
1239 | spin_unlock_irqrestore(&gpio_lock, flags); | |
1240 | fail: | |
1241 | /* failures here can mean systems won't boot... */ | |
1242 | pr_err("gpiochip_add: gpios %d..%d (%s) failed to register\n", | |
1243 | chip->base, chip->base + chip->ngpio - 1, | |
1244 | chip->label ? : "generic"); | |
1245 | return status; | |
1246 | } | |
1247 | EXPORT_SYMBOL_GPL(gpiochip_add); | |
1248 | ||
1249 | /** | |
1250 | * gpiochip_remove() - unregister a gpio_chip | |
1251 | * @chip: the chip to unregister | |
1252 | * | |
1253 | * A gpio_chip with any GPIOs still requested may not be removed. | |
1254 | */ | |
1255 | int gpiochip_remove(struct gpio_chip *chip) | |
1256 | { | |
1257 | unsigned long flags; | |
1258 | int status = 0; | |
1259 | unsigned id; | |
1260 | ||
1261 | spin_lock_irqsave(&gpio_lock, flags); | |
1262 | ||
1263 | gpiochip_remove_pin_ranges(chip); | |
1264 | of_gpiochip_remove(chip); | |
1265 | ||
1266 | for (id = 0; id < chip->ngpio; id++) { | |
1267 | if (test_bit(FLAG_REQUESTED, &chip->desc[id].flags)) { | |
1268 | status = -EBUSY; | |
1269 | break; | |
1270 | } | |
1271 | } | |
1272 | if (status == 0) { | |
1273 | for (id = 0; id < chip->ngpio; id++) | |
1274 | chip->desc[id].chip = NULL; | |
1275 | ||
1276 | list_del(&chip->list); | |
1277 | } | |
1278 | ||
1279 | spin_unlock_irqrestore(&gpio_lock, flags); | |
1280 | ||
1281 | if (status == 0) | |
1282 | gpiochip_unexport(chip); | |
1283 | ||
1284 | return status; | |
1285 | } | |
1286 | EXPORT_SYMBOL_GPL(gpiochip_remove); | |
1287 | ||
1288 | /** | |
1289 | * gpiochip_find() - iterator for locating a specific gpio_chip | |
1290 | * @data: data to pass to match function | |
1291 | * @callback: Callback function to check gpio_chip | |
1292 | * | |
1293 | * Similar to bus_find_device. It returns a reference to a gpio_chip as | |
1294 | * determined by a user supplied @match callback. The callback should return | |
1295 | * 0 if the device doesn't match and non-zero if it does. If the callback is | |
1296 | * non-zero, this function will return to the caller and not iterate over any | |
1297 | * more gpio_chips. | |
1298 | */ | |
1299 | struct gpio_chip *gpiochip_find(void *data, | |
1300 | int (*match)(struct gpio_chip *chip, | |
1301 | void *data)) | |
1302 | { | |
1303 | struct gpio_chip *chip; | |
1304 | unsigned long flags; | |
1305 | ||
1306 | spin_lock_irqsave(&gpio_lock, flags); | |
1307 | list_for_each_entry(chip, &gpio_chips, list) | |
1308 | if (match(chip, data)) | |
1309 | break; | |
1310 | ||
1311 | /* No match? */ | |
1312 | if (&chip->list == &gpio_chips) | |
1313 | chip = NULL; | |
1314 | spin_unlock_irqrestore(&gpio_lock, flags); | |
1315 | ||
1316 | return chip; | |
1317 | } | |
1318 | EXPORT_SYMBOL_GPL(gpiochip_find); | |
1319 | ||
1320 | #ifdef CONFIG_PINCTRL | |
1321 | ||
1322 | /** | |
1323 | * gpiochip_add_pin_range() - add a range for GPIO <-> pin mapping | |
1324 | * @chip: the gpiochip to add the range for | |
1325 | * @pinctrl_name: the dev_name() of the pin controller to map to | |
1326 | * @gpio_offset: the start offset in the current gpio_chip number space | |
1327 | * @pin_offset: the start offset in the pin controller number space | |
1328 | * @npins: the number of pins from the offset of each pin space (GPIO and | |
1329 | * pin controller) to accumulate in this range | |
1330 | */ | |
1331 | int gpiochip_add_pin_range(struct gpio_chip *chip, const char *pinctl_name, | |
1332 | unsigned int gpio_offset, unsigned int pin_offset, | |
1333 | unsigned int npins) | |
1334 | { | |
1335 | struct gpio_pin_range *pin_range; | |
1336 | int ret; | |
1337 | ||
1338 | pin_range = kzalloc(sizeof(*pin_range), GFP_KERNEL); | |
1339 | if (!pin_range) { | |
1340 | pr_err("%s: GPIO chip: failed to allocate pin ranges\n", | |
1341 | chip->label); | |
1342 | return -ENOMEM; | |
1343 | } | |
1344 | ||
1345 | /* Use local offset as range ID */ | |
1346 | pin_range->range.id = gpio_offset; | |
1347 | pin_range->range.gc = chip; | |
1348 | pin_range->range.name = chip->label; | |
1349 | pin_range->range.base = chip->base + gpio_offset; | |
1350 | pin_range->range.pin_base = pin_offset; | |
1351 | pin_range->range.npins = npins; | |
1352 | pin_range->pctldev = pinctrl_find_and_add_gpio_range(pinctl_name, | |
1353 | &pin_range->range); | |
1354 | if (IS_ERR(pin_range->pctldev)) { | |
1355 | ret = PTR_ERR(pin_range->pctldev); | |
1356 | pr_err("%s: GPIO chip: could not create pin range\n", | |
1357 | chip->label); | |
1358 | kfree(pin_range); | |
1359 | return ret; | |
1360 | } | |
1361 | pr_debug("GPIO chip %s: created GPIO range %d->%d ==> %s PIN %d->%d\n", | |
1362 | chip->label, gpio_offset, gpio_offset + npins - 1, | |
1363 | pinctl_name, | |
1364 | pin_offset, pin_offset + npins - 1); | |
1365 | ||
1366 | list_add_tail(&pin_range->node, &chip->pin_ranges); | |
1367 | ||
1368 | return 0; | |
1369 | } | |
1370 | EXPORT_SYMBOL_GPL(gpiochip_add_pin_range); | |
1371 | ||
1372 | /** | |
1373 | * gpiochip_remove_pin_ranges() - remove all the GPIO <-> pin mappings | |
1374 | * @chip: the chip to remove all the mappings for | |
1375 | */ | |
1376 | void gpiochip_remove_pin_ranges(struct gpio_chip *chip) | |
1377 | { | |
1378 | struct gpio_pin_range *pin_range, *tmp; | |
1379 | ||
1380 | list_for_each_entry_safe(pin_range, tmp, &chip->pin_ranges, node) { | |
1381 | list_del(&pin_range->node); | |
1382 | pinctrl_remove_gpio_range(pin_range->pctldev, | |
1383 | &pin_range->range); | |
1384 | kfree(pin_range); | |
1385 | } | |
1386 | } | |
1387 | EXPORT_SYMBOL_GPL(gpiochip_remove_pin_ranges); | |
1388 | ||
1389 | #endif /* CONFIG_PINCTRL */ | |
1390 | ||
1391 | /* These "optional" allocation calls help prevent drivers from stomping | |
1392 | * on each other, and help provide better diagnostics in debugfs. | |
1393 | * They're called even less than the "set direction" calls. | |
1394 | */ | |
1395 | static int gpiod_request(struct gpio_desc *desc, const char *label) | |
1396 | { | |
1397 | struct gpio_chip *chip; | |
1398 | int status = -EPROBE_DEFER; | |
1399 | unsigned long flags; | |
1400 | ||
1401 | if (!desc || !desc->chip) { | |
1402 | pr_warn("%s: invalid GPIO\n", __func__); | |
1403 | return -EINVAL; | |
1404 | } | |
1405 | ||
1406 | spin_lock_irqsave(&gpio_lock, flags); | |
1407 | ||
1408 | chip = desc->chip; | |
1409 | ||
1410 | if (!try_module_get(chip->owner)) | |
1411 | goto done; | |
1412 | ||
1413 | /* NOTE: gpio_request() can be called in early boot, | |
1414 | * before IRQs are enabled, for non-sleeping (SOC) GPIOs. | |
1415 | */ | |
1416 | ||
1417 | if (test_and_set_bit(FLAG_REQUESTED, &desc->flags) == 0) { | |
1418 | desc_set_label(desc, label ? : "?"); | |
1419 | status = 0; | |
1420 | } else { | |
1421 | status = -EBUSY; | |
1422 | module_put(chip->owner); | |
1423 | goto done; | |
1424 | } | |
1425 | ||
1426 | if (chip->request) { | |
1427 | /* chip->request may sleep */ | |
1428 | spin_unlock_irqrestore(&gpio_lock, flags); | |
1429 | status = chip->request(chip, gpio_chip_hwgpio(desc)); | |
1430 | spin_lock_irqsave(&gpio_lock, flags); | |
1431 | ||
1432 | if (status < 0) { | |
1433 | desc_set_label(desc, NULL); | |
1434 | module_put(chip->owner); | |
1435 | clear_bit(FLAG_REQUESTED, &desc->flags); | |
1436 | goto done; | |
1437 | } | |
1438 | } | |
1439 | if (chip->get_direction) { | |
1440 | /* chip->get_direction may sleep */ | |
1441 | spin_unlock_irqrestore(&gpio_lock, flags); | |
1442 | gpiod_get_direction(desc); | |
1443 | spin_lock_irqsave(&gpio_lock, flags); | |
1444 | } | |
1445 | done: | |
1446 | if (status) | |
1447 | pr_debug("_gpio_request: gpio-%d (%s) status %d\n", | |
1448 | desc_to_gpio(desc), label ? : "?", status); | |
1449 | spin_unlock_irqrestore(&gpio_lock, flags); | |
1450 | return status; | |
1451 | } | |
1452 | ||
1453 | int gpio_request(unsigned gpio, const char *label) | |
1454 | { | |
1455 | return gpiod_request(gpio_to_desc(gpio), label); | |
1456 | } | |
1457 | EXPORT_SYMBOL_GPL(gpio_request); | |
1458 | ||
1459 | static void gpiod_free(struct gpio_desc *desc) | |
1460 | { | |
1461 | unsigned long flags; | |
1462 | struct gpio_chip *chip; | |
1463 | ||
1464 | might_sleep(); | |
1465 | ||
1466 | if (!desc) { | |
1467 | WARN_ON(extra_checks); | |
1468 | return; | |
1469 | } | |
1470 | ||
1471 | gpiod_unexport(desc); | |
1472 | ||
1473 | spin_lock_irqsave(&gpio_lock, flags); | |
1474 | ||
1475 | chip = desc->chip; | |
1476 | if (chip && test_bit(FLAG_REQUESTED, &desc->flags)) { | |
1477 | if (chip->free) { | |
1478 | spin_unlock_irqrestore(&gpio_lock, flags); | |
1479 | might_sleep_if(chip->can_sleep); | |
1480 | chip->free(chip, gpio_chip_hwgpio(desc)); | |
1481 | spin_lock_irqsave(&gpio_lock, flags); | |
1482 | } | |
1483 | desc_set_label(desc, NULL); | |
1484 | module_put(desc->chip->owner); | |
1485 | clear_bit(FLAG_ACTIVE_LOW, &desc->flags); | |
1486 | clear_bit(FLAG_REQUESTED, &desc->flags); | |
1487 | clear_bit(FLAG_OPEN_DRAIN, &desc->flags); | |
1488 | clear_bit(FLAG_OPEN_SOURCE, &desc->flags); | |
1489 | } else | |
1490 | WARN_ON(extra_checks); | |
1491 | ||
1492 | spin_unlock_irqrestore(&gpio_lock, flags); | |
1493 | } | |
1494 | ||
1495 | void gpio_free(unsigned gpio) | |
1496 | { | |
1497 | gpiod_free(gpio_to_desc(gpio)); | |
1498 | } | |
1499 | EXPORT_SYMBOL_GPL(gpio_free); | |
1500 | ||
1501 | /** | |
1502 | * gpio_request_one - request a single GPIO with initial configuration | |
1503 | * @gpio: the GPIO number | |
1504 | * @flags: GPIO configuration as specified by GPIOF_* | |
1505 | * @label: a literal description string of this GPIO | |
1506 | */ | |
1507 | int gpio_request_one(unsigned gpio, unsigned long flags, const char *label) | |
1508 | { | |
1509 | struct gpio_desc *desc; | |
1510 | int err; | |
1511 | ||
1512 | desc = gpio_to_desc(gpio); | |
1513 | ||
1514 | err = gpiod_request(desc, label); | |
1515 | if (err) | |
1516 | return err; | |
1517 | ||
1518 | if (flags & GPIOF_OPEN_DRAIN) | |
1519 | set_bit(FLAG_OPEN_DRAIN, &desc->flags); | |
1520 | ||
1521 | if (flags & GPIOF_OPEN_SOURCE) | |
1522 | set_bit(FLAG_OPEN_SOURCE, &desc->flags); | |
1523 | ||
1524 | if (flags & GPIOF_DIR_IN) | |
1525 | err = gpiod_direction_input(desc); | |
1526 | else | |
1527 | err = gpiod_direction_output(desc, | |
1528 | (flags & GPIOF_INIT_HIGH) ? 1 : 0); | |
1529 | ||
1530 | if (err) | |
1531 | goto free_gpio; | |
1532 | ||
1533 | if (flags & GPIOF_EXPORT) { | |
1534 | err = gpiod_export(desc, flags & GPIOF_EXPORT_CHANGEABLE); | |
1535 | if (err) | |
1536 | goto free_gpio; | |
1537 | } | |
1538 | ||
1539 | return 0; | |
1540 | ||
1541 | free_gpio: | |
1542 | gpiod_free(desc); | |
1543 | return err; | |
1544 | } | |
1545 | EXPORT_SYMBOL_GPL(gpio_request_one); | |
1546 | ||
1547 | /** | |
1548 | * gpio_request_array - request multiple GPIOs in a single call | |
1549 | * @array: array of the 'struct gpio' | |
1550 | * @num: how many GPIOs in the array | |
1551 | */ | |
1552 | int gpio_request_array(const struct gpio *array, size_t num) | |
1553 | { | |
1554 | int i, err; | |
1555 | ||
1556 | for (i = 0; i < num; i++, array++) { | |
1557 | err = gpio_request_one(array->gpio, array->flags, array->label); | |
1558 | if (err) | |
1559 | goto err_free; | |
1560 | } | |
1561 | return 0; | |
1562 | ||
1563 | err_free: | |
1564 | while (i--) | |
1565 | gpio_free((--array)->gpio); | |
1566 | return err; | |
1567 | } | |
1568 | EXPORT_SYMBOL_GPL(gpio_request_array); | |
1569 | ||
1570 | /** | |
1571 | * gpio_free_array - release multiple GPIOs in a single call | |
1572 | * @array: array of the 'struct gpio' | |
1573 | * @num: how many GPIOs in the array | |
1574 | */ | |
1575 | void gpio_free_array(const struct gpio *array, size_t num) | |
1576 | { | |
1577 | while (num--) | |
1578 | gpio_free((array++)->gpio); | |
1579 | } | |
1580 | EXPORT_SYMBOL_GPL(gpio_free_array); | |
1581 | ||
1582 | /** | |
1583 | * gpiochip_is_requested - return string iff signal was requested | |
1584 | * @chip: controller managing the signal | |
1585 | * @offset: of signal within controller's 0..(ngpio - 1) range | |
1586 | * | |
1587 | * Returns NULL if the GPIO is not currently requested, else a string. | |
1588 | * If debugfs support is enabled, the string returned is the label passed | |
1589 | * to gpio_request(); otherwise it is a meaningless constant. | |
1590 | * | |
1591 | * This function is for use by GPIO controller drivers. The label can | |
1592 | * help with diagnostics, and knowing that the signal is used as a GPIO | |
1593 | * can help avoid accidentally multiplexing it to another controller. | |
1594 | */ | |
1595 | const char *gpiochip_is_requested(struct gpio_chip *chip, unsigned offset) | |
1596 | { | |
1597 | struct gpio_desc *desc; | |
1598 | ||
1599 | if (!GPIO_OFFSET_VALID(chip, offset)) | |
1600 | return NULL; | |
1601 | ||
1602 | desc = &chip->desc[offset]; | |
1603 | ||
1604 | if (test_bit(FLAG_REQUESTED, &desc->flags) == 0) | |
1605 | return NULL; | |
1606 | #ifdef CONFIG_DEBUG_FS | |
1607 | return desc->label; | |
1608 | #else | |
1609 | return "?"; | |
1610 | #endif | |
1611 | } | |
1612 | EXPORT_SYMBOL_GPL(gpiochip_is_requested); | |
1613 | ||
1614 | ||
1615 | /* Drivers MUST set GPIO direction before making get/set calls. In | |
1616 | * some cases this is done in early boot, before IRQs are enabled. | |
1617 | * | |
1618 | * As a rule these aren't called more than once (except for drivers | |
1619 | * using the open-drain emulation idiom) so these are natural places | |
1620 | * to accumulate extra debugging checks. Note that we can't (yet) | |
1621 | * rely on gpio_request() having been called beforehand. | |
1622 | */ | |
1623 | ||
1624 | static int gpiod_direction_input(struct gpio_desc *desc) | |
1625 | { | |
1626 | unsigned long flags; | |
1627 | struct gpio_chip *chip; | |
1628 | int status = -EINVAL; | |
1629 | int offset; | |
1630 | ||
1631 | if (!desc || !desc->chip) { | |
1632 | pr_warn("%s: invalid GPIO\n", __func__); | |
1633 | return -EINVAL; | |
1634 | } | |
1635 | ||
1636 | chip = desc->chip; | |
1637 | if (!chip->get || !chip->direction_input) { | |
1638 | pr_warn("%s: missing get() or direction_input() operations\n", | |
1639 | __func__); | |
1640 | return -EIO; | |
1641 | } | |
1642 | ||
1643 | spin_lock_irqsave(&gpio_lock, flags); | |
1644 | ||
1645 | status = gpio_ensure_requested(desc); | |
1646 | if (status < 0) | |
1647 | goto fail; | |
1648 | ||
1649 | /* now we know the gpio is valid and chip won't vanish */ | |
1650 | ||
1651 | spin_unlock_irqrestore(&gpio_lock, flags); | |
1652 | ||
1653 | might_sleep_if(chip->can_sleep); | |
1654 | ||
1655 | offset = gpio_chip_hwgpio(desc); | |
1656 | if (status) { | |
1657 | status = chip->request(chip, offset); | |
1658 | if (status < 0) { | |
1659 | pr_debug("GPIO-%d: chip request fail, %d\n", | |
1660 | desc_to_gpio(desc), status); | |
1661 | /* and it's not available to anyone else ... | |
1662 | * gpio_request() is the fully clean solution. | |
1663 | */ | |
1664 | goto lose; | |
1665 | } | |
1666 | } | |
1667 | ||
1668 | status = chip->direction_input(chip, offset); | |
1669 | if (status == 0) | |
1670 | clear_bit(FLAG_IS_OUT, &desc->flags); | |
1671 | ||
1672 | trace_gpio_direction(desc_to_gpio(desc), 1, status); | |
1673 | lose: | |
1674 | return status; | |
1675 | fail: | |
1676 | spin_unlock_irqrestore(&gpio_lock, flags); | |
1677 | if (status) | |
1678 | pr_debug("%s: gpio-%d status %d\n", __func__, | |
1679 | desc_to_gpio(desc), status); | |
1680 | return status; | |
1681 | } | |
1682 | ||
1683 | int gpio_direction_input(unsigned gpio) | |
1684 | { | |
1685 | return gpiod_direction_input(gpio_to_desc(gpio)); | |
1686 | } | |
1687 | EXPORT_SYMBOL_GPL(gpio_direction_input); | |
1688 | ||
1689 | static int gpiod_direction_output(struct gpio_desc *desc, int value) | |
1690 | { | |
1691 | unsigned long flags; | |
1692 | struct gpio_chip *chip; | |
1693 | int status = -EINVAL; | |
1694 | int offset; | |
1695 | ||
1696 | if (!desc || !desc->chip) { | |
1697 | pr_warn("%s: invalid GPIO\n", __func__); | |
1698 | return -EINVAL; | |
1699 | } | |
1700 | ||
1701 | /* Open drain pin should not be driven to 1 */ | |
1702 | if (value && test_bit(FLAG_OPEN_DRAIN, &desc->flags)) | |
1703 | return gpiod_direction_input(desc); | |
1704 | ||
1705 | /* Open source pin should not be driven to 0 */ | |
1706 | if (!value && test_bit(FLAG_OPEN_SOURCE, &desc->flags)) | |
1707 | return gpiod_direction_input(desc); | |
1708 | ||
1709 | chip = desc->chip; | |
1710 | if (!chip->set || !chip->direction_output) { | |
1711 | pr_warn("%s: missing set() or direction_output() operations\n", | |
1712 | __func__); | |
1713 | return -EIO; | |
1714 | } | |
1715 | ||
1716 | spin_lock_irqsave(&gpio_lock, flags); | |
1717 | ||
1718 | status = gpio_ensure_requested(desc); | |
1719 | if (status < 0) | |
1720 | goto fail; | |
1721 | ||
1722 | /* now we know the gpio is valid and chip won't vanish */ | |
1723 | ||
1724 | spin_unlock_irqrestore(&gpio_lock, flags); | |
1725 | ||
1726 | might_sleep_if(chip->can_sleep); | |
1727 | ||
1728 | offset = gpio_chip_hwgpio(desc); | |
1729 | if (status) { | |
1730 | status = chip->request(chip, offset); | |
1731 | if (status < 0) { | |
1732 | pr_debug("GPIO-%d: chip request fail, %d\n", | |
1733 | desc_to_gpio(desc), status); | |
1734 | /* and it's not available to anyone else ... | |
1735 | * gpio_request() is the fully clean solution. | |
1736 | */ | |
1737 | goto lose; | |
1738 | } | |
1739 | } | |
1740 | ||
1741 | status = chip->direction_output(chip, offset, value); | |
1742 | if (status == 0) | |
1743 | set_bit(FLAG_IS_OUT, &desc->flags); | |
1744 | trace_gpio_value(desc_to_gpio(desc), 0, value); | |
1745 | trace_gpio_direction(desc_to_gpio(desc), 0, status); | |
1746 | lose: | |
1747 | return status; | |
1748 | fail: | |
1749 | spin_unlock_irqrestore(&gpio_lock, flags); | |
1750 | if (status) | |
1751 | pr_debug("%s: gpio-%d status %d\n", __func__, | |
1752 | desc_to_gpio(desc), status); | |
1753 | return status; | |
1754 | } | |
1755 | ||
1756 | int gpio_direction_output(unsigned gpio, int value) | |
1757 | { | |
1758 | return gpiod_direction_output(gpio_to_desc(gpio), value); | |
1759 | } | |
1760 | EXPORT_SYMBOL_GPL(gpio_direction_output); | |
1761 | ||
1762 | /** | |
1763 | * gpio_set_debounce - sets @debounce time for a @gpio | |
1764 | * @gpio: the gpio to set debounce time | |
1765 | * @debounce: debounce time is microseconds | |
1766 | * | |
1767 | * returns -ENOTSUPP if the controller does not support setting | |
1768 | * debounce. | |
1769 | */ | |
1770 | static int gpiod_set_debounce(struct gpio_desc *desc, unsigned debounce) | |
1771 | { | |
1772 | unsigned long flags; | |
1773 | struct gpio_chip *chip; | |
1774 | int status = -EINVAL; | |
1775 | int offset; | |
1776 | ||
1777 | if (!desc || !desc->chip) { | |
1778 | pr_warn("%s: invalid GPIO\n", __func__); | |
1779 | return -EINVAL; | |
1780 | } | |
1781 | ||
1782 | chip = desc->chip; | |
1783 | if (!chip->set || !chip->set_debounce) { | |
1784 | pr_debug("%s: missing set() or set_debounce() operations\n", | |
1785 | __func__); | |
1786 | return -ENOTSUPP; | |
1787 | } | |
1788 | ||
1789 | spin_lock_irqsave(&gpio_lock, flags); | |
1790 | ||
1791 | status = gpio_ensure_requested(desc); | |
1792 | if (status < 0) | |
1793 | goto fail; | |
1794 | ||
1795 | /* now we know the gpio is valid and chip won't vanish */ | |
1796 | ||
1797 | spin_unlock_irqrestore(&gpio_lock, flags); | |
1798 | ||
1799 | might_sleep_if(chip->can_sleep); | |
1800 | ||
1801 | offset = gpio_chip_hwgpio(desc); | |
1802 | return chip->set_debounce(chip, offset, debounce); | |
1803 | ||
1804 | fail: | |
1805 | spin_unlock_irqrestore(&gpio_lock, flags); | |
1806 | if (status) | |
1807 | pr_debug("%s: gpio-%d status %d\n", __func__, | |
1808 | desc_to_gpio(desc), status); | |
1809 | ||
1810 | return status; | |
1811 | } | |
1812 | ||
1813 | int gpio_set_debounce(unsigned gpio, unsigned debounce) | |
1814 | { | |
1815 | return gpiod_set_debounce(gpio_to_desc(gpio), debounce); | |
1816 | } | |
1817 | EXPORT_SYMBOL_GPL(gpio_set_debounce); | |
1818 | ||
1819 | /* I/O calls are only valid after configuration completed; the relevant | |
1820 | * "is this a valid GPIO" error checks should already have been done. | |
1821 | * | |
1822 | * "Get" operations are often inlinable as reading a pin value register, | |
1823 | * and masking the relevant bit in that register. | |
1824 | * | |
1825 | * When "set" operations are inlinable, they involve writing that mask to | |
1826 | * one register to set a low value, or a different register to set it high. | |
1827 | * Otherwise locking is needed, so there may be little value to inlining. | |
1828 | * | |
1829 | *------------------------------------------------------------------------ | |
1830 | * | |
1831 | * IMPORTANT!!! The hot paths -- get/set value -- assume that callers | |
1832 | * have requested the GPIO. That can include implicit requesting by | |
1833 | * a direction setting call. Marking a gpio as requested locks its chip | |
1834 | * in memory, guaranteeing that these table lookups need no more locking | |
1835 | * and that gpiochip_remove() will fail. | |
1836 | * | |
1837 | * REVISIT when debugging, consider adding some instrumentation to ensure | |
1838 | * that the GPIO was actually requested. | |
1839 | */ | |
1840 | ||
1841 | /** | |
1842 | * __gpio_get_value() - return a gpio's value | |
1843 | * @gpio: gpio whose value will be returned | |
1844 | * Context: any | |
1845 | * | |
1846 | * This is used directly or indirectly to implement gpio_get_value(). | |
1847 | * It returns the zero or nonzero value provided by the associated | |
1848 | * gpio_chip.get() method; or zero if no such method is provided. | |
1849 | */ | |
1850 | static int gpiod_get_value(const struct gpio_desc *desc) | |
1851 | { | |
1852 | struct gpio_chip *chip; | |
1853 | int value; | |
1854 | int offset; | |
1855 | ||
1856 | if (!desc) | |
1857 | return 0; | |
1858 | chip = desc->chip; | |
1859 | offset = gpio_chip_hwgpio(desc); | |
1860 | /* Should be using gpio_get_value_cansleep() */ | |
1861 | WARN_ON(chip->can_sleep); | |
1862 | value = chip->get ? chip->get(chip, offset) : 0; | |
1863 | trace_gpio_value(desc_to_gpio(desc), 1, value); | |
1864 | return value; | |
1865 | } | |
1866 | ||
1867 | int __gpio_get_value(unsigned gpio) | |
1868 | { | |
1869 | return gpiod_get_value(gpio_to_desc(gpio)); | |
1870 | } | |
1871 | EXPORT_SYMBOL_GPL(__gpio_get_value); | |
1872 | ||
1873 | /* | |
1874 | * _gpio_set_open_drain_value() - Set the open drain gpio's value. | |
1875 | * @gpio: Gpio whose state need to be set. | |
1876 | * @chip: Gpio chip. | |
1877 | * @value: Non-zero for setting it HIGH otherise it will set to LOW. | |
1878 | */ | |
1879 | static void _gpio_set_open_drain_value(struct gpio_desc *desc, int value) | |
1880 | { | |
1881 | int err = 0; | |
1882 | struct gpio_chip *chip = desc->chip; | |
1883 | int offset = gpio_chip_hwgpio(desc); | |
1884 | ||
1885 | if (value) { | |
1886 | err = chip->direction_input(chip, offset); | |
1887 | if (!err) | |
1888 | clear_bit(FLAG_IS_OUT, &desc->flags); | |
1889 | } else { | |
1890 | err = chip->direction_output(chip, offset, 0); | |
1891 | if (!err) | |
1892 | set_bit(FLAG_IS_OUT, &desc->flags); | |
1893 | } | |
1894 | trace_gpio_direction(desc_to_gpio(desc), value, err); | |
1895 | if (err < 0) | |
1896 | pr_err("%s: Error in set_value for open drain gpio%d err %d\n", | |
1897 | __func__, desc_to_gpio(desc), err); | |
1898 | } | |
1899 | ||
1900 | /* | |
1901 | * _gpio_set_open_source() - Set the open source gpio's value. | |
1902 | * @gpio: Gpio whose state need to be set. | |
1903 | * @chip: Gpio chip. | |
1904 | * @value: Non-zero for setting it HIGH otherise it will set to LOW. | |
1905 | */ | |
1906 | static void _gpio_set_open_source_value(struct gpio_desc *desc, int value) | |
1907 | { | |
1908 | int err = 0; | |
1909 | struct gpio_chip *chip = desc->chip; | |
1910 | int offset = gpio_chip_hwgpio(desc); | |
1911 | ||
1912 | if (value) { | |
1913 | err = chip->direction_output(chip, offset, 1); | |
1914 | if (!err) | |
1915 | set_bit(FLAG_IS_OUT, &desc->flags); | |
1916 | } else { | |
1917 | err = chip->direction_input(chip, offset); | |
1918 | if (!err) | |
1919 | clear_bit(FLAG_IS_OUT, &desc->flags); | |
1920 | } | |
1921 | trace_gpio_direction(desc_to_gpio(desc), !value, err); | |
1922 | if (err < 0) | |
1923 | pr_err("%s: Error in set_value for open source gpio%d err %d\n", | |
1924 | __func__, desc_to_gpio(desc), err); | |
1925 | } | |
1926 | ||
1927 | /** | |
1928 | * __gpio_set_value() - assign a gpio's value | |
1929 | * @gpio: gpio whose value will be assigned | |
1930 | * @value: value to assign | |
1931 | * Context: any | |
1932 | * | |
1933 | * This is used directly or indirectly to implement gpio_set_value(). | |
1934 | * It invokes the associated gpio_chip.set() method. | |
1935 | */ | |
1936 | static void gpiod_set_value(struct gpio_desc *desc, int value) | |
1937 | { | |
1938 | struct gpio_chip *chip; | |
1939 | ||
1940 | if (!desc) | |
1941 | return; | |
1942 | chip = desc->chip; | |
1943 | /* Should be using gpio_set_value_cansleep() */ | |
1944 | WARN_ON(chip->can_sleep); | |
1945 | trace_gpio_value(desc_to_gpio(desc), 0, value); | |
1946 | if (test_bit(FLAG_OPEN_DRAIN, &desc->flags)) | |
1947 | _gpio_set_open_drain_value(desc, value); | |
1948 | else if (test_bit(FLAG_OPEN_SOURCE, &desc->flags)) | |
1949 | _gpio_set_open_source_value(desc, value); | |
1950 | else | |
1951 | chip->set(chip, gpio_chip_hwgpio(desc), value); | |
1952 | } | |
1953 | ||
1954 | void __gpio_set_value(unsigned gpio, int value) | |
1955 | { | |
1956 | return gpiod_set_value(gpio_to_desc(gpio), value); | |
1957 | } | |
1958 | EXPORT_SYMBOL_GPL(__gpio_set_value); | |
1959 | ||
1960 | /** | |
1961 | * __gpio_cansleep() - report whether gpio value access will sleep | |
1962 | * @gpio: gpio in question | |
1963 | * Context: any | |
1964 | * | |
1965 | * This is used directly or indirectly to implement gpio_cansleep(). It | |
1966 | * returns nonzero if access reading or writing the GPIO value can sleep. | |
1967 | */ | |
1968 | static int gpiod_cansleep(const struct gpio_desc *desc) | |
1969 | { | |
1970 | if (!desc) | |
1971 | return 0; | |
1972 | /* only call this on GPIOs that are valid! */ | |
1973 | return desc->chip->can_sleep; | |
1974 | } | |
1975 | ||
1976 | int __gpio_cansleep(unsigned gpio) | |
1977 | { | |
1978 | return gpiod_cansleep(gpio_to_desc(gpio)); | |
1979 | } | |
1980 | EXPORT_SYMBOL_GPL(__gpio_cansleep); | |
1981 | ||
1982 | /** | |
1983 | * __gpio_to_irq() - return the IRQ corresponding to a GPIO | |
1984 | * @gpio: gpio whose IRQ will be returned (already requested) | |
1985 | * Context: any | |
1986 | * | |
1987 | * This is used directly or indirectly to implement gpio_to_irq(). | |
1988 | * It returns the number of the IRQ signaled by this (input) GPIO, | |
1989 | * or a negative errno. | |
1990 | */ | |
1991 | static int gpiod_to_irq(const struct gpio_desc *desc) | |
1992 | { | |
1993 | struct gpio_chip *chip; | |
1994 | int offset; | |
1995 | ||
1996 | if (!desc) | |
1997 | return -EINVAL; | |
1998 | chip = desc->chip; | |
1999 | offset = gpio_chip_hwgpio(desc); | |
2000 | return chip->to_irq ? chip->to_irq(chip, offset) : -ENXIO; | |
2001 | } | |
2002 | ||
2003 | int __gpio_to_irq(unsigned gpio) | |
2004 | { | |
2005 | return gpiod_to_irq(gpio_to_desc(gpio)); | |
2006 | } | |
2007 | EXPORT_SYMBOL_GPL(__gpio_to_irq); | |
2008 | ||
2009 | ||
2010 | /* There's no value in making it easy to inline GPIO calls that may sleep. | |
2011 | * Common examples include ones connected to I2C or SPI chips. | |
2012 | */ | |
2013 | ||
2014 | static int gpiod_get_value_cansleep(const struct gpio_desc *desc) | |
2015 | { | |
2016 | struct gpio_chip *chip; | |
2017 | int value; | |
2018 | int offset; | |
2019 | ||
2020 | might_sleep_if(extra_checks); | |
2021 | if (!desc) | |
2022 | return 0; | |
2023 | chip = desc->chip; | |
2024 | offset = gpio_chip_hwgpio(desc); | |
2025 | value = chip->get ? chip->get(chip, offset) : 0; | |
2026 | trace_gpio_value(desc_to_gpio(desc), 1, value); | |
2027 | return value; | |
2028 | } | |
2029 | ||
2030 | int gpio_get_value_cansleep(unsigned gpio) | |
2031 | { | |
2032 | return gpiod_get_value_cansleep(gpio_to_desc(gpio)); | |
2033 | } | |
2034 | EXPORT_SYMBOL_GPL(gpio_get_value_cansleep); | |
2035 | ||
2036 | static void gpiod_set_value_cansleep(struct gpio_desc *desc, int value) | |
2037 | { | |
2038 | struct gpio_chip *chip; | |
2039 | ||
2040 | might_sleep_if(extra_checks); | |
2041 | if (!desc) | |
2042 | return; | |
2043 | chip = desc->chip; | |
2044 | trace_gpio_value(desc_to_gpio(desc), 0, value); | |
2045 | if (test_bit(FLAG_OPEN_DRAIN, &desc->flags)) | |
2046 | _gpio_set_open_drain_value(desc, value); | |
2047 | else if (test_bit(FLAG_OPEN_SOURCE, &desc->flags)) | |
2048 | _gpio_set_open_source_value(desc, value); | |
2049 | else | |
2050 | chip->set(chip, gpio_chip_hwgpio(desc), value); | |
2051 | } | |
2052 | ||
2053 | void gpio_set_value_cansleep(unsigned gpio, int value) | |
2054 | { | |
2055 | return gpiod_set_value_cansleep(gpio_to_desc(gpio), value); | |
2056 | } | |
2057 | EXPORT_SYMBOL_GPL(gpio_set_value_cansleep); | |
2058 | ||
2059 | #ifdef CONFIG_DEBUG_FS | |
2060 | ||
2061 | static void gpiolib_dbg_show(struct seq_file *s, struct gpio_chip *chip) | |
2062 | { | |
2063 | unsigned i; | |
2064 | unsigned gpio = chip->base; | |
2065 | struct gpio_desc *gdesc = &chip->desc[0]; | |
2066 | int is_out; | |
2067 | ||
2068 | for (i = 0; i < chip->ngpio; i++, gpio++, gdesc++) { | |
2069 | if (!test_bit(FLAG_REQUESTED, &gdesc->flags)) | |
2070 | continue; | |
2071 | ||
2072 | gpiod_get_direction(gdesc); | |
2073 | is_out = test_bit(FLAG_IS_OUT, &gdesc->flags); | |
2074 | seq_printf(s, " gpio-%-3d (%-20.20s) %s %s", | |
2075 | gpio, gdesc->label, | |
2076 | is_out ? "out" : "in ", | |
2077 | chip->get | |
2078 | ? (chip->get(chip, i) ? "hi" : "lo") | |
2079 | : "? "); | |
2080 | seq_printf(s, "\n"); | |
2081 | } | |
2082 | } | |
2083 | ||
2084 | static void *gpiolib_seq_start(struct seq_file *s, loff_t *pos) | |
2085 | { | |
2086 | unsigned long flags; | |
2087 | struct gpio_chip *chip = NULL; | |
2088 | loff_t index = *pos; | |
2089 | ||
2090 | s->private = ""; | |
2091 | ||
2092 | spin_lock_irqsave(&gpio_lock, flags); | |
2093 | list_for_each_entry(chip, &gpio_chips, list) | |
2094 | if (index-- == 0) { | |
2095 | spin_unlock_irqrestore(&gpio_lock, flags); | |
2096 | return chip; | |
2097 | } | |
2098 | spin_unlock_irqrestore(&gpio_lock, flags); | |
2099 | ||
2100 | return NULL; | |
2101 | } | |
2102 | ||
2103 | static void *gpiolib_seq_next(struct seq_file *s, void *v, loff_t *pos) | |
2104 | { | |
2105 | unsigned long flags; | |
2106 | struct gpio_chip *chip = v; | |
2107 | void *ret = NULL; | |
2108 | ||
2109 | spin_lock_irqsave(&gpio_lock, flags); | |
2110 | if (list_is_last(&chip->list, &gpio_chips)) | |
2111 | ret = NULL; | |
2112 | else | |
2113 | ret = list_entry(chip->list.next, struct gpio_chip, list); | |
2114 | spin_unlock_irqrestore(&gpio_lock, flags); | |
2115 | ||
2116 | s->private = "\n"; | |
2117 | ++*pos; | |
2118 | ||
2119 | return ret; | |
2120 | } | |
2121 | ||
2122 | static void gpiolib_seq_stop(struct seq_file *s, void *v) | |
2123 | { | |
2124 | } | |
2125 | ||
2126 | static int gpiolib_seq_show(struct seq_file *s, void *v) | |
2127 | { | |
2128 | struct gpio_chip *chip = v; | |
2129 | struct device *dev; | |
2130 | ||
2131 | seq_printf(s, "%sGPIOs %d-%d", (char *)s->private, | |
2132 | chip->base, chip->base + chip->ngpio - 1); | |
2133 | dev = chip->dev; | |
2134 | if (dev) | |
2135 | seq_printf(s, ", %s/%s", dev->bus ? dev->bus->name : "no-bus", | |
2136 | dev_name(dev)); | |
2137 | if (chip->label) | |
2138 | seq_printf(s, ", %s", chip->label); | |
2139 | if (chip->can_sleep) | |
2140 | seq_printf(s, ", can sleep"); | |
2141 | seq_printf(s, ":\n"); | |
2142 | ||
2143 | if (chip->dbg_show) | |
2144 | chip->dbg_show(s, chip); | |
2145 | else | |
2146 | gpiolib_dbg_show(s, chip); | |
2147 | ||
2148 | return 0; | |
2149 | } | |
2150 | ||
2151 | static const struct seq_operations gpiolib_seq_ops = { | |
2152 | .start = gpiolib_seq_start, | |
2153 | .next = gpiolib_seq_next, | |
2154 | .stop = gpiolib_seq_stop, | |
2155 | .show = gpiolib_seq_show, | |
2156 | }; | |
2157 | ||
2158 | static int gpiolib_open(struct inode *inode, struct file *file) | |
2159 | { | |
2160 | return seq_open(file, &gpiolib_seq_ops); | |
2161 | } | |
2162 | ||
2163 | static const struct file_operations gpiolib_operations = { | |
2164 | .owner = THIS_MODULE, | |
2165 | .open = gpiolib_open, | |
2166 | .read = seq_read, | |
2167 | .llseek = seq_lseek, | |
2168 | .release = seq_release, | |
2169 | }; | |
2170 | ||
2171 | static int __init gpiolib_debugfs_init(void) | |
2172 | { | |
2173 | /* /sys/kernel/debug/gpio */ | |
2174 | (void) debugfs_create_file("gpio", S_IFREG | S_IRUGO, | |
2175 | NULL, NULL, &gpiolib_operations); | |
2176 | return 0; | |
2177 | } | |
2178 | subsys_initcall(gpiolib_debugfs_init); | |
2179 | ||
2180 | #endif /* DEBUG_FS */ |