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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 = strict_strtol(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 = strict_strtol(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 = strict_strtol(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 = strict_strtol(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) { |
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 | if (chip == NULL) |
1410 | goto done; |
1411 | |
1412 | if (!try_module_get(chip->owner)) |
1413 | goto done; |
1414 | |
1415 | /* NOTE: gpio_request() can be called in early boot, |
1416 | * before IRQs are enabled, for non-sleeping (SOC) GPIOs. |
1417 | */ |
1418 | |
1419 | if (test_and_set_bit(FLAG_REQUESTED, &desc->flags) == 0) { |
1420 | desc_set_label(desc, label ? : "?"); |
1421 | status = 0; |
1422 | } else { |
1423 | status = -EBUSY; |
1424 | module_put(chip->owner); |
1425 | goto done; |
1426 | } |
1427 | |
1428 | if (chip->request) { |
1429 | /* chip->request may sleep */ |
1430 | spin_unlock_irqrestore(&gpio_lock, flags); |
1431 | status = chip->request(chip, gpio_chip_hwgpio(desc)); |
1432 | spin_lock_irqsave(&gpio_lock, flags); |
1433 | |
1434 | if (status < 0) { |
1435 | desc_set_label(desc, NULL); |
1436 | module_put(chip->owner); |
1437 | clear_bit(FLAG_REQUESTED, &desc->flags); |
1438 | goto done; |
1439 | } |
1440 | } |
1441 | if (chip->get_direction) { |
1442 | /* chip->get_direction may sleep */ |
1443 | spin_unlock_irqrestore(&gpio_lock, flags); |
1444 | gpiod_get_direction(desc); |
1445 | spin_lock_irqsave(&gpio_lock, flags); |
1446 | } |
1447 | done: |
1448 | if (status) |
1449 | pr_debug("_gpio_request: gpio-%d (%s) status %d\n", |
1450 | desc_to_gpio(desc), label ? : "?", status); |
1451 | spin_unlock_irqrestore(&gpio_lock, flags); |
1452 | return status; |
1453 | } |
1454 | |
1455 | int gpio_request(unsigned gpio, const char *label) |
1456 | { |
1457 | return gpiod_request(gpio_to_desc(gpio), label); |
1458 | } |
1459 | EXPORT_SYMBOL_GPL(gpio_request); |
1460 | |
1461 | static void gpiod_free(struct gpio_desc *desc) |
1462 | { |
1463 | unsigned long flags; |
1464 | struct gpio_chip *chip; |
1465 | |
1466 | might_sleep(); |
1467 | |
1468 | if (!desc) { |
1469 | WARN_ON(extra_checks); |
1470 | return; |
1471 | } |
1472 | |
1473 | gpiod_unexport(desc); |
1474 | |
1475 | spin_lock_irqsave(&gpio_lock, flags); |
1476 | |
1477 | chip = desc->chip; |
1478 | if (chip && test_bit(FLAG_REQUESTED, &desc->flags)) { |
1479 | if (chip->free) { |
1480 | spin_unlock_irqrestore(&gpio_lock, flags); |
1481 | might_sleep_if(chip->can_sleep); |
1482 | chip->free(chip, gpio_chip_hwgpio(desc)); |
1483 | spin_lock_irqsave(&gpio_lock, flags); |
1484 | } |
1485 | desc_set_label(desc, NULL); |
1486 | module_put(desc->chip->owner); |
1487 | clear_bit(FLAG_ACTIVE_LOW, &desc->flags); |
1488 | clear_bit(FLAG_REQUESTED, &desc->flags); |
1489 | clear_bit(FLAG_OPEN_DRAIN, &desc->flags); |
1490 | clear_bit(FLAG_OPEN_SOURCE, &desc->flags); |
1491 | } else |
1492 | WARN_ON(extra_checks); |
1493 | |
1494 | spin_unlock_irqrestore(&gpio_lock, flags); |
1495 | } |
1496 | |
1497 | void gpio_free(unsigned gpio) |
1498 | { |
1499 | gpiod_free(gpio_to_desc(gpio)); |
1500 | } |
1501 | EXPORT_SYMBOL_GPL(gpio_free); |
1502 | |
1503 | /** |
1504 | * gpio_request_one - request a single GPIO with initial configuration |
1505 | * @gpio: the GPIO number |
1506 | * @flags: GPIO configuration as specified by GPIOF_* |
1507 | * @label: a literal description string of this GPIO |
1508 | */ |
1509 | int gpio_request_one(unsigned gpio, unsigned long flags, const char *label) |
1510 | { |
1511 | struct gpio_desc *desc; |
1512 | int err; |
1513 | |
1514 | desc = gpio_to_desc(gpio); |
1515 | |
1516 | err = gpiod_request(desc, label); |
1517 | if (err) |
1518 | return err; |
1519 | |
1520 | if (flags & GPIOF_OPEN_DRAIN) |
1521 | set_bit(FLAG_OPEN_DRAIN, &desc->flags); |
1522 | |
1523 | if (flags & GPIOF_OPEN_SOURCE) |
1524 | set_bit(FLAG_OPEN_SOURCE, &desc->flags); |
1525 | |
1526 | if (flags & GPIOF_DIR_IN) |
1527 | err = gpiod_direction_input(desc); |
1528 | else |
1529 | err = gpiod_direction_output(desc, |
1530 | (flags & GPIOF_INIT_HIGH) ? 1 : 0); |
1531 | |
1532 | if (err) |
1533 | goto free_gpio; |
1534 | |
1535 | if (flags & GPIOF_EXPORT) { |
1536 | err = gpiod_export(desc, flags & GPIOF_EXPORT_CHANGEABLE); |
1537 | if (err) |
1538 | goto free_gpio; |
1539 | } |
1540 | |
1541 | return 0; |
1542 | |
1543 | free_gpio: |
1544 | gpiod_free(desc); |
1545 | return err; |
1546 | } |
1547 | EXPORT_SYMBOL_GPL(gpio_request_one); |
1548 | |
1549 | /** |
1550 | * gpio_request_array - request multiple GPIOs in a single call |
1551 | * @array: array of the 'struct gpio' |
1552 | * @num: how many GPIOs in the array |
1553 | */ |
1554 | int gpio_request_array(const struct gpio *array, size_t num) |
1555 | { |
1556 | int i, err; |
1557 | |
1558 | for (i = 0; i < num; i++, array++) { |
1559 | err = gpio_request_one(array->gpio, array->flags, array->label); |
1560 | if (err) |
1561 | goto err_free; |
1562 | } |
1563 | return 0; |
1564 | |
1565 | err_free: |
1566 | while (i--) |
1567 | gpio_free((--array)->gpio); |
1568 | return err; |
1569 | } |
1570 | EXPORT_SYMBOL_GPL(gpio_request_array); |
1571 | |
1572 | /** |
1573 | * gpio_free_array - release multiple GPIOs in a single call |
1574 | * @array: array of the 'struct gpio' |
1575 | * @num: how many GPIOs in the array |
1576 | */ |
1577 | void gpio_free_array(const struct gpio *array, size_t num) |
1578 | { |
1579 | while (num--) |
1580 | gpio_free((array++)->gpio); |
1581 | } |
1582 | EXPORT_SYMBOL_GPL(gpio_free_array); |
1583 | |
1584 | /** |
1585 | * gpiochip_is_requested - return string iff signal was requested |
1586 | * @chip: controller managing the signal |
1587 | * @offset: of signal within controller's 0..(ngpio - 1) range |
1588 | * |
1589 | * Returns NULL if the GPIO is not currently requested, else a string. |
1590 | * If debugfs support is enabled, the string returned is the label passed |
1591 | * to gpio_request(); otherwise it is a meaningless constant. |
1592 | * |
1593 | * This function is for use by GPIO controller drivers. The label can |
1594 | * help with diagnostics, and knowing that the signal is used as a GPIO |
1595 | * can help avoid accidentally multiplexing it to another controller. |
1596 | */ |
1597 | const char *gpiochip_is_requested(struct gpio_chip *chip, unsigned offset) |
1598 | { |
1599 | struct gpio_desc *desc; |
1600 | |
1601 | if (!GPIO_OFFSET_VALID(chip, offset)) |
1602 | return NULL; |
1603 | |
1604 | desc = &chip->desc[offset]; |
1605 | |
1606 | if (test_bit(FLAG_REQUESTED, &desc->flags) == 0) |
1607 | return NULL; |
1608 | #ifdef CONFIG_DEBUG_FS |
1609 | return desc->label; |
1610 | #else |
1611 | return "?"; |
1612 | #endif |
1613 | } |
1614 | EXPORT_SYMBOL_GPL(gpiochip_is_requested); |
1615 | |
1616 | |
1617 | /* Drivers MUST set GPIO direction before making get/set calls. In |
1618 | * some cases this is done in early boot, before IRQs are enabled. |
1619 | * |
1620 | * As a rule these aren't called more than once (except for drivers |
1621 | * using the open-drain emulation idiom) so these are natural places |
1622 | * to accumulate extra debugging checks. Note that we can't (yet) |
1623 | * rely on gpio_request() having been called beforehand. |
1624 | */ |
1625 | |
1626 | static int gpiod_direction_input(struct gpio_desc *desc) |
1627 | { |
1628 | unsigned long flags; |
1629 | struct gpio_chip *chip; |
1630 | int status = -EINVAL; |
1631 | int offset; |
1632 | |
1633 | if (!desc) { |
1634 | pr_warn("%s: invalid GPIO\n", __func__); |
1635 | return -EINVAL; |
1636 | } |
1637 | |
1638 | spin_lock_irqsave(&gpio_lock, flags); |
1639 | |
1640 | chip = desc->chip; |
1641 | if (!chip || !chip->get || !chip->direction_input) |
1642 | goto fail; |
1643 | status = gpio_ensure_requested(desc); |
1644 | if (status < 0) |
1645 | goto fail; |
1646 | |
1647 | /* now we know the gpio is valid and chip won't vanish */ |
1648 | |
1649 | spin_unlock_irqrestore(&gpio_lock, flags); |
1650 | |
1651 | might_sleep_if(chip->can_sleep); |
1652 | |
1653 | offset = gpio_chip_hwgpio(desc); |
1654 | if (status) { |
1655 | status = chip->request(chip, offset); |
1656 | if (status < 0) { |
1657 | pr_debug("GPIO-%d: chip request fail, %d\n", |
1658 | desc_to_gpio(desc), status); |
1659 | /* and it's not available to anyone else ... |
1660 | * gpio_request() is the fully clean solution. |
1661 | */ |
1662 | goto lose; |
1663 | } |
1664 | } |
1665 | |
1666 | status = chip->direction_input(chip, offset); |
1667 | if (status == 0) |
1668 | clear_bit(FLAG_IS_OUT, &desc->flags); |
1669 | |
1670 | trace_gpio_direction(desc_to_gpio(desc), 1, status); |
1671 | lose: |
1672 | return status; |
1673 | fail: |
1674 | spin_unlock_irqrestore(&gpio_lock, flags); |
1675 | if (status) |
1676 | pr_debug("%s: gpio-%d status %d\n", __func__, |
1677 | desc_to_gpio(desc), status); |
1678 | return status; |
1679 | } |
1680 | |
1681 | int gpio_direction_input(unsigned gpio) |
1682 | { |
1683 | return gpiod_direction_input(gpio_to_desc(gpio)); |
1684 | } |
1685 | EXPORT_SYMBOL_GPL(gpio_direction_input); |
1686 | |
1687 | static int gpiod_direction_output(struct gpio_desc *desc, int value) |
1688 | { |
1689 | unsigned long flags; |
1690 | struct gpio_chip *chip; |
1691 | int status = -EINVAL; |
1692 | int offset; |
1693 | |
1694 | if (!desc) { |
1695 | pr_warn("%s: invalid GPIO\n", __func__); |
1696 | return -EINVAL; |
1697 | } |
1698 | |
1699 | /* Open drain pin should not be driven to 1 */ |
1700 | if (value && test_bit(FLAG_OPEN_DRAIN, &desc->flags)) |
1701 | return gpiod_direction_input(desc); |
1702 | |
1703 | /* Open source pin should not be driven to 0 */ |
1704 | if (!value && test_bit(FLAG_OPEN_SOURCE, &desc->flags)) |
1705 | return gpiod_direction_input(desc); |
1706 | |
1707 | spin_lock_irqsave(&gpio_lock, flags); |
1708 | |
1709 | chip = desc->chip; |
1710 | if (!chip || !chip->set || !chip->direction_output) |
1711 | goto fail; |
1712 | status = gpio_ensure_requested(desc); |
1713 | if (status < 0) |
1714 | goto fail; |
1715 | |
1716 | /* now we know the gpio is valid and chip won't vanish */ |
1717 | |
1718 | spin_unlock_irqrestore(&gpio_lock, flags); |
1719 | |
1720 | might_sleep_if(chip->can_sleep); |
1721 | |
1722 | offset = gpio_chip_hwgpio(desc); |
1723 | if (status) { |
1724 | status = chip->request(chip, offset); |
1725 | if (status < 0) { |
1726 | pr_debug("GPIO-%d: chip request fail, %d\n", |
1727 | desc_to_gpio(desc), status); |
1728 | /* and it's not available to anyone else ... |
1729 | * gpio_request() is the fully clean solution. |
1730 | */ |
1731 | goto lose; |
1732 | } |
1733 | } |
1734 | |
1735 | status = chip->direction_output(chip, offset, value); |
1736 | if (status == 0) |
1737 | set_bit(FLAG_IS_OUT, &desc->flags); |
1738 | trace_gpio_value(desc_to_gpio(desc), 0, value); |
1739 | trace_gpio_direction(desc_to_gpio(desc), 0, status); |
1740 | lose: |
1741 | return status; |
1742 | fail: |
1743 | spin_unlock_irqrestore(&gpio_lock, flags); |
1744 | if (status) |
1745 | pr_debug("%s: gpio-%d status %d\n", __func__, |
1746 | desc_to_gpio(desc), status); |
1747 | return status; |
1748 | } |
1749 | |
1750 | int gpio_direction_output(unsigned gpio, int value) |
1751 | { |
1752 | return gpiod_direction_output(gpio_to_desc(gpio), value); |
1753 | } |
1754 | EXPORT_SYMBOL_GPL(gpio_direction_output); |
1755 | |
1756 | /** |
1757 | * gpio_set_debounce - sets @debounce time for a @gpio |
1758 | * @gpio: the gpio to set debounce time |
1759 | * @debounce: debounce time is microseconds |
1760 | */ |
1761 | static int gpiod_set_debounce(struct gpio_desc *desc, unsigned debounce) |
1762 | { |
1763 | unsigned long flags; |
1764 | struct gpio_chip *chip; |
1765 | int status = -EINVAL; |
1766 | int offset; |
1767 | |
1768 | if (!desc) { |
1769 | pr_warn("%s: invalid GPIO\n", __func__); |
1770 | return -EINVAL; |
1771 | } |
1772 | |
1773 | spin_lock_irqsave(&gpio_lock, flags); |
1774 | |
1775 | chip = desc->chip; |
1776 | if (!chip || !chip->set || !chip->set_debounce) |
1777 | goto fail; |
1778 | |
1779 | status = gpio_ensure_requested(desc); |
1780 | if (status < 0) |
1781 | goto fail; |
1782 | |
1783 | /* now we know the gpio is valid and chip won't vanish */ |
1784 | |
1785 | spin_unlock_irqrestore(&gpio_lock, flags); |
1786 | |
1787 | might_sleep_if(chip->can_sleep); |
1788 | |
1789 | offset = gpio_chip_hwgpio(desc); |
1790 | return chip->set_debounce(chip, offset, debounce); |
1791 | |
1792 | fail: |
1793 | spin_unlock_irqrestore(&gpio_lock, flags); |
1794 | if (status) |
1795 | pr_debug("%s: gpio-%d status %d\n", __func__, |
1796 | desc_to_gpio(desc), status); |
1797 | |
1798 | return status; |
1799 | } |
1800 | |
1801 | int gpio_set_debounce(unsigned gpio, unsigned debounce) |
1802 | { |
1803 | return gpiod_set_debounce(gpio_to_desc(gpio), debounce); |
1804 | } |
1805 | EXPORT_SYMBOL_GPL(gpio_set_debounce); |
1806 | |
1807 | /* I/O calls are only valid after configuration completed; the relevant |
1808 | * "is this a valid GPIO" error checks should already have been done. |
1809 | * |
1810 | * "Get" operations are often inlinable as reading a pin value register, |
1811 | * and masking the relevant bit in that register. |
1812 | * |
1813 | * When "set" operations are inlinable, they involve writing that mask to |
1814 | * one register to set a low value, or a different register to set it high. |
1815 | * Otherwise locking is needed, so there may be little value to inlining. |
1816 | * |
1817 | *------------------------------------------------------------------------ |
1818 | * |
1819 | * IMPORTANT!!! The hot paths -- get/set value -- assume that callers |
1820 | * have requested the GPIO. That can include implicit requesting by |
1821 | * a direction setting call. Marking a gpio as requested locks its chip |
1822 | * in memory, guaranteeing that these table lookups need no more locking |
1823 | * and that gpiochip_remove() will fail. |
1824 | * |
1825 | * REVISIT when debugging, consider adding some instrumentation to ensure |
1826 | * that the GPIO was actually requested. |
1827 | */ |
1828 | |
1829 | /** |
1830 | * __gpio_get_value() - return a gpio's value |
1831 | * @gpio: gpio whose value will be returned |
1832 | * Context: any |
1833 | * |
1834 | * This is used directly or indirectly to implement gpio_get_value(). |
1835 | * It returns the zero or nonzero value provided by the associated |
1836 | * gpio_chip.get() method; or zero if no such method is provided. |
1837 | */ |
1838 | static int gpiod_get_value(const struct gpio_desc *desc) |
1839 | { |
1840 | struct gpio_chip *chip; |
1841 | int value; |
1842 | int offset; |
1843 | |
1844 | if (!desc) |
1845 | return 0; |
1846 | chip = desc->chip; |
1847 | offset = gpio_chip_hwgpio(desc); |
1848 | /* Should be using gpio_get_value_cansleep() */ |
1849 | WARN_ON(chip->can_sleep); |
1850 | value = chip->get ? chip->get(chip, offset) : 0; |
1851 | trace_gpio_value(desc_to_gpio(desc), 1, value); |
1852 | return value; |
1853 | } |
1854 | |
1855 | int __gpio_get_value(unsigned gpio) |
1856 | { |
1857 | return gpiod_get_value(gpio_to_desc(gpio)); |
1858 | } |
1859 | EXPORT_SYMBOL_GPL(__gpio_get_value); |
1860 | |
1861 | /* |
1862 | * _gpio_set_open_drain_value() - Set the open drain gpio's value. |
1863 | * @gpio: Gpio whose state need to be set. |
1864 | * @chip: Gpio chip. |
1865 | * @value: Non-zero for setting it HIGH otherise it will set to LOW. |
1866 | */ |
1867 | static void _gpio_set_open_drain_value(struct gpio_desc *desc, int value) |
1868 | { |
1869 | int err = 0; |
1870 | struct gpio_chip *chip = desc->chip; |
1871 | int offset = gpio_chip_hwgpio(desc); |
1872 | |
1873 | if (value) { |
1874 | err = chip->direction_input(chip, offset); |
1875 | if (!err) |
1876 | clear_bit(FLAG_IS_OUT, &desc->flags); |
1877 | } else { |
1878 | err = chip->direction_output(chip, offset, 0); |
1879 | if (!err) |
1880 | set_bit(FLAG_IS_OUT, &desc->flags); |
1881 | } |
1882 | trace_gpio_direction(desc_to_gpio(desc), value, err); |
1883 | if (err < 0) |
1884 | pr_err("%s: Error in set_value for open drain gpio%d err %d\n", |
1885 | __func__, desc_to_gpio(desc), err); |
1886 | } |
1887 | |
1888 | /* |
1889 | * _gpio_set_open_source() - Set the open source gpio's value. |
1890 | * @gpio: Gpio whose state need to be set. |
1891 | * @chip: Gpio chip. |
1892 | * @value: Non-zero for setting it HIGH otherise it will set to LOW. |
1893 | */ |
1894 | static void _gpio_set_open_source_value(struct gpio_desc *desc, int value) |
1895 | { |
1896 | int err = 0; |
1897 | struct gpio_chip *chip = desc->chip; |
1898 | int offset = gpio_chip_hwgpio(desc); |
1899 | |
1900 | if (value) { |
1901 | err = chip->direction_output(chip, offset, 1); |
1902 | if (!err) |
1903 | set_bit(FLAG_IS_OUT, &desc->flags); |
1904 | } else { |
1905 | err = chip->direction_input(chip, offset); |
1906 | if (!err) |
1907 | clear_bit(FLAG_IS_OUT, &desc->flags); |
1908 | } |
1909 | trace_gpio_direction(desc_to_gpio(desc), !value, err); |
1910 | if (err < 0) |
1911 | pr_err("%s: Error in set_value for open source gpio%d err %d\n", |
1912 | __func__, desc_to_gpio(desc), err); |
1913 | } |
1914 | |
1915 | /** |
1916 | * __gpio_set_value() - assign a gpio's value |
1917 | * @gpio: gpio whose value will be assigned |
1918 | * @value: value to assign |
1919 | * Context: any |
1920 | * |
1921 | * This is used directly or indirectly to implement gpio_set_value(). |
1922 | * It invokes the associated gpio_chip.set() method. |
1923 | */ |
1924 | static void gpiod_set_value(struct gpio_desc *desc, int value) |
1925 | { |
1926 | struct gpio_chip *chip; |
1927 | |
1928 | if (!desc) |
1929 | return; |
1930 | chip = desc->chip; |
1931 | /* Should be using gpio_set_value_cansleep() */ |
1932 | WARN_ON(chip->can_sleep); |
1933 | trace_gpio_value(desc_to_gpio(desc), 0, value); |
1934 | if (test_bit(FLAG_OPEN_DRAIN, &desc->flags)) |
1935 | _gpio_set_open_drain_value(desc, value); |
1936 | else if (test_bit(FLAG_OPEN_SOURCE, &desc->flags)) |
1937 | _gpio_set_open_source_value(desc, value); |
1938 | else |
1939 | chip->set(chip, gpio_chip_hwgpio(desc), value); |
1940 | } |
1941 | |
1942 | void __gpio_set_value(unsigned gpio, int value) |
1943 | { |
1944 | return gpiod_set_value(gpio_to_desc(gpio), value); |
1945 | } |
1946 | EXPORT_SYMBOL_GPL(__gpio_set_value); |
1947 | |
1948 | /** |
1949 | * __gpio_cansleep() - report whether gpio value access will sleep |
1950 | * @gpio: gpio in question |
1951 | * Context: any |
1952 | * |
1953 | * This is used directly or indirectly to implement gpio_cansleep(). It |
1954 | * returns nonzero if access reading or writing the GPIO value can sleep. |
1955 | */ |
1956 | static int gpiod_cansleep(const struct gpio_desc *desc) |
1957 | { |
1958 | if (!desc) |
1959 | return 0; |
1960 | /* only call this on GPIOs that are valid! */ |
1961 | return desc->chip->can_sleep; |
1962 | } |
1963 | |
1964 | int __gpio_cansleep(unsigned gpio) |
1965 | { |
1966 | return gpiod_cansleep(gpio_to_desc(gpio)); |
1967 | } |
1968 | EXPORT_SYMBOL_GPL(__gpio_cansleep); |
1969 | |
1970 | /** |
1971 | * __gpio_to_irq() - return the IRQ corresponding to a GPIO |
1972 | * @gpio: gpio whose IRQ will be returned (already requested) |
1973 | * Context: any |
1974 | * |
1975 | * This is used directly or indirectly to implement gpio_to_irq(). |
1976 | * It returns the number of the IRQ signaled by this (input) GPIO, |
1977 | * or a negative errno. |
1978 | */ |
1979 | static int gpiod_to_irq(const struct gpio_desc *desc) |
1980 | { |
1981 | struct gpio_chip *chip; |
1982 | int offset; |
1983 | |
1984 | if (!desc) |
1985 | return -EINVAL; |
1986 | chip = desc->chip; |
1987 | offset = gpio_chip_hwgpio(desc); |
1988 | return chip->to_irq ? chip->to_irq(chip, offset) : -ENXIO; |
1989 | } |
1990 | |
1991 | int __gpio_to_irq(unsigned gpio) |
1992 | { |
1993 | return gpiod_to_irq(gpio_to_desc(gpio)); |
1994 | } |
1995 | EXPORT_SYMBOL_GPL(__gpio_to_irq); |
1996 | |
1997 | |
1998 | /* There's no value in making it easy to inline GPIO calls that may sleep. |
1999 | * Common examples include ones connected to I2C or SPI chips. |
2000 | */ |
2001 | |
2002 | static int gpiod_get_value_cansleep(const struct gpio_desc *desc) |
2003 | { |
2004 | struct gpio_chip *chip; |
2005 | int value; |
2006 | int offset; |
2007 | |
2008 | might_sleep_if(extra_checks); |
2009 | if (!desc) |
2010 | return 0; |
2011 | chip = desc->chip; |
2012 | offset = gpio_chip_hwgpio(desc); |
2013 | value = chip->get ? chip->get(chip, offset) : 0; |
2014 | trace_gpio_value(desc_to_gpio(desc), 1, value); |
2015 | return value; |
2016 | } |
2017 | |
2018 | int gpio_get_value_cansleep(unsigned gpio) |
2019 | { |
2020 | return gpiod_get_value_cansleep(gpio_to_desc(gpio)); |
2021 | } |
2022 | EXPORT_SYMBOL_GPL(gpio_get_value_cansleep); |
2023 | |
2024 | static void gpiod_set_value_cansleep(struct gpio_desc *desc, int value) |
2025 | { |
2026 | struct gpio_chip *chip; |
2027 | |
2028 | might_sleep_if(extra_checks); |
2029 | if (!desc) |
2030 | return; |
2031 | chip = desc->chip; |
2032 | trace_gpio_value(desc_to_gpio(desc), 0, value); |
2033 | if (test_bit(FLAG_OPEN_DRAIN, &desc->flags)) |
2034 | _gpio_set_open_drain_value(desc, value); |
2035 | else if (test_bit(FLAG_OPEN_SOURCE, &desc->flags)) |
2036 | _gpio_set_open_source_value(desc, value); |
2037 | else |
2038 | chip->set(chip, gpio_chip_hwgpio(desc), value); |
2039 | } |
2040 | |
2041 | void gpio_set_value_cansleep(unsigned gpio, int value) |
2042 | { |
2043 | return gpiod_set_value_cansleep(gpio_to_desc(gpio), value); |
2044 | } |
2045 | EXPORT_SYMBOL_GPL(gpio_set_value_cansleep); |
2046 | |
2047 | #ifdef CONFIG_DEBUG_FS |
2048 | |
2049 | static void gpiolib_dbg_show(struct seq_file *s, struct gpio_chip *chip) |
2050 | { |
2051 | unsigned i; |
2052 | unsigned gpio = chip->base; |
2053 | struct gpio_desc *gdesc = &chip->desc[0]; |
2054 | int is_out; |
2055 | |
2056 | for (i = 0; i < chip->ngpio; i++, gpio++, gdesc++) { |
2057 | if (!test_bit(FLAG_REQUESTED, &gdesc->flags)) |
2058 | continue; |
2059 | |
2060 | gpiod_get_direction(gdesc); |
2061 | is_out = test_bit(FLAG_IS_OUT, &gdesc->flags); |
2062 | seq_printf(s, " gpio-%-3d (%-20.20s) %s %s", |
2063 | gpio, gdesc->label, |
2064 | is_out ? "out" : "in ", |
2065 | chip->get |
2066 | ? (chip->get(chip, i) ? "hi" : "lo") |
2067 | : "? "); |
2068 | seq_printf(s, "\n"); |
2069 | } |
2070 | } |
2071 | |
2072 | static void *gpiolib_seq_start(struct seq_file *s, loff_t *pos) |
2073 | { |
2074 | unsigned long flags; |
2075 | struct gpio_chip *chip = NULL; |
2076 | loff_t index = *pos; |
2077 | |
2078 | s->private = ""; |
2079 | |
2080 | spin_lock_irqsave(&gpio_lock, flags); |
2081 | list_for_each_entry(chip, &gpio_chips, list) |
2082 | if (index-- == 0) { |
2083 | spin_unlock_irqrestore(&gpio_lock, flags); |
2084 | return chip; |
2085 | } |
2086 | spin_unlock_irqrestore(&gpio_lock, flags); |
2087 | |
2088 | return NULL; |
2089 | } |
2090 | |
2091 | static void *gpiolib_seq_next(struct seq_file *s, void *v, loff_t *pos) |
2092 | { |
2093 | unsigned long flags; |
2094 | struct gpio_chip *chip = v; |
2095 | void *ret = NULL; |
2096 | |
2097 | spin_lock_irqsave(&gpio_lock, flags); |
2098 | if (list_is_last(&chip->list, &gpio_chips)) |
2099 | ret = NULL; |
2100 | else |
2101 | ret = list_entry(chip->list.next, struct gpio_chip, list); |
2102 | spin_unlock_irqrestore(&gpio_lock, flags); |
2103 | |
2104 | s->private = "\n"; |
2105 | ++*pos; |
2106 | |
2107 | return ret; |
2108 | } |
2109 | |
2110 | static void gpiolib_seq_stop(struct seq_file *s, void *v) |
2111 | { |
2112 | } |
2113 | |
2114 | static int gpiolib_seq_show(struct seq_file *s, void *v) |
2115 | { |
2116 | struct gpio_chip *chip = v; |
2117 | struct device *dev; |
2118 | |
2119 | seq_printf(s, "%sGPIOs %d-%d", (char *)s->private, |
2120 | chip->base, chip->base + chip->ngpio - 1); |
2121 | dev = chip->dev; |
2122 | if (dev) |
2123 | seq_printf(s, ", %s/%s", dev->bus ? dev->bus->name : "no-bus", |
2124 | dev_name(dev)); |
2125 | if (chip->label) |
2126 | seq_printf(s, ", %s", chip->label); |
2127 | if (chip->can_sleep) |
2128 | seq_printf(s, ", can sleep"); |
2129 | seq_printf(s, ":\n"); |
2130 | |
2131 | if (chip->dbg_show) |
2132 | chip->dbg_show(s, chip); |
2133 | else |
2134 | gpiolib_dbg_show(s, chip); |
2135 | |
2136 | return 0; |
2137 | } |
2138 | |
2139 | static const struct seq_operations gpiolib_seq_ops = { |
2140 | .start = gpiolib_seq_start, |
2141 | .next = gpiolib_seq_next, |
2142 | .stop = gpiolib_seq_stop, |
2143 | .show = gpiolib_seq_show, |
2144 | }; |
2145 | |
2146 | static int gpiolib_open(struct inode *inode, struct file *file) |
2147 | { |
2148 | return seq_open(file, &gpiolib_seq_ops); |
2149 | } |
2150 | |
2151 | static const struct file_operations gpiolib_operations = { |
2152 | .owner = THIS_MODULE, |
2153 | .open = gpiolib_open, |
2154 | .read = seq_read, |
2155 | .llseek = seq_lseek, |
2156 | .release = seq_release, |
2157 | }; |
2158 | |
2159 | static int __init gpiolib_debugfs_init(void) |
2160 | { |
2161 | /* /sys/kernel/debug/gpio */ |
2162 | (void) debugfs_create_file("gpio", S_IFREG | S_IRUGO, |
2163 | NULL, NULL, &gpiolib_operations); |
2164 | return 0; |
2165 | } |
2166 | subsys_initcall(gpiolib_debugfs_init); |
2167 | |
2168 | #endif /* DEBUG_FS */ |
2169 |
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