Commit | Line | Data |
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d2876d08 DB |
1 | #include <linux/kernel.h> |
2 | #include <linux/module.h> | |
ff77c352 | 3 | #include <linux/interrupt.h> |
d2876d08 DB |
4 | #include <linux/irq.h> |
5 | #include <linux/spinlock.h> | |
d8f388d8 DB |
6 | #include <linux/device.h> |
7 | #include <linux/err.h> | |
8 | #include <linux/debugfs.h> | |
9 | #include <linux/seq_file.h> | |
10 | #include <linux/gpio.h> | |
391c970c | 11 | #include <linux/of_gpio.h> |
ff77c352 | 12 | #include <linux/idr.h> |
5a0e3ad6 | 13 | #include <linux/slab.h> |
d2876d08 | 14 | |
3f397c21 UKK |
15 | #define CREATE_TRACE_POINTS |
16 | #include <trace/events/gpio.h> | |
d2876d08 DB |
17 | |
18 | /* Optional implementation infrastructure for GPIO interfaces. | |
19 | * | |
20 | * Platforms may want to use this if they tend to use very many GPIOs | |
21 | * that aren't part of a System-On-Chip core; or across I2C/SPI/etc. | |
22 | * | |
23 | * When kernel footprint or instruction count is an issue, simpler | |
24 | * implementations may be preferred. The GPIO programming interface | |
25 | * allows for inlining speed-critical get/set operations for common | |
26 | * cases, so that access to SOC-integrated GPIOs can sometimes cost | |
27 | * only an instruction or two per bit. | |
28 | */ | |
29 | ||
30 | ||
31 | /* When debugging, extend minimal trust to callers and platform code. | |
32 | * Also emit diagnostic messages that may help initial bringup, when | |
33 | * board setup or driver bugs are most common. | |
34 | * | |
35 | * Otherwise, minimize overhead in what may be bitbanging codepaths. | |
36 | */ | |
37 | #ifdef DEBUG | |
38 | #define extra_checks 1 | |
39 | #else | |
40 | #define extra_checks 0 | |
41 | #endif | |
42 | ||
43 | /* gpio_lock prevents conflicts during gpio_desc[] table updates. | |
44 | * While any GPIO is requested, its gpio_chip is not removable; | |
45 | * each GPIO's "requested" flag serves as a lock and refcount. | |
46 | */ | |
47 | static DEFINE_SPINLOCK(gpio_lock); | |
48 | ||
49 | struct gpio_desc { | |
50 | struct gpio_chip *chip; | |
51 | unsigned long flags; | |
52 | /* flag symbols are bit numbers */ | |
53 | #define FLAG_REQUESTED 0 | |
54 | #define FLAG_IS_OUT 1 | |
169b6a7a | 55 | #define FLAG_RESERVED 2 |
d8f388d8 DB |
56 | #define FLAG_EXPORT 3 /* protected by sysfs_lock */ |
57 | #define FLAG_SYSFS 4 /* exported via /sys/class/gpio/control */ | |
ff77c352 DG |
58 | #define FLAG_TRIG_FALL 5 /* trigger on falling edge */ |
59 | #define FLAG_TRIG_RISE 6 /* trigger on rising edge */ | |
07697461 | 60 | #define FLAG_ACTIVE_LOW 7 /* sysfs value has active low */ |
aca5ce14 | 61 | #define FLAG_OPEN_DRAIN 8 /* Gpio is open drain type */ |
25553ff0 | 62 | #define FLAG_OPEN_SOURCE 9 /* Gpio is open source type */ |
ff77c352 | 63 | |
5ba1821d | 64 | #define ID_SHIFT 16 /* add new flags before this one */ |
ff77c352 | 65 | |
5ba1821d | 66 | #define GPIO_FLAGS_MASK ((1 << ID_SHIFT) - 1) |
ff77c352 | 67 | #define GPIO_TRIGGER_MASK (BIT(FLAG_TRIG_FALL) | BIT(FLAG_TRIG_RISE)) |
d2876d08 DB |
68 | |
69 | #ifdef CONFIG_DEBUG_FS | |
70 | const char *label; | |
71 | #endif | |
72 | }; | |
73 | static struct gpio_desc gpio_desc[ARCH_NR_GPIOS]; | |
74 | ||
ff77c352 | 75 | #ifdef CONFIG_GPIO_SYSFS |
5ba1821d | 76 | static DEFINE_IDR(dirent_idr); |
ff77c352 DG |
77 | #endif |
78 | ||
d2876d08 DB |
79 | static inline void desc_set_label(struct gpio_desc *d, const char *label) |
80 | { | |
81 | #ifdef CONFIG_DEBUG_FS | |
82 | d->label = label; | |
83 | #endif | |
84 | } | |
85 | ||
86 | /* Warn when drivers omit gpio_request() calls -- legal but ill-advised | |
87 | * when setting direction, and otherwise illegal. Until board setup code | |
88 | * and drivers use explicit requests everywhere (which won't happen when | |
89 | * those calls have no teeth) we can't avoid autorequesting. This nag | |
35e8bb51 DB |
90 | * message should motivate switching to explicit requests... so should |
91 | * the weaker cleanup after faults, compared to gpio_request(). | |
8a0cecff DB |
92 | * |
93 | * NOTE: the autorequest mechanism is going away; at this point it's | |
94 | * only "legal" in the sense that (old) code using it won't break yet, | |
95 | * but instead only triggers a WARN() stack dump. | |
d2876d08 | 96 | */ |
35e8bb51 | 97 | static int gpio_ensure_requested(struct gpio_desc *desc, unsigned offset) |
d2876d08 | 98 | { |
8a0cecff DB |
99 | const struct gpio_chip *chip = desc->chip; |
100 | const int gpio = chip->base + offset; | |
35e8bb51 | 101 | |
8a0cecff DB |
102 | if (WARN(test_and_set_bit(FLAG_REQUESTED, &desc->flags) == 0, |
103 | "autorequest GPIO-%d\n", gpio)) { | |
35e8bb51 DB |
104 | if (!try_module_get(chip->owner)) { |
105 | pr_err("GPIO-%d: module can't be gotten \n", gpio); | |
106 | clear_bit(FLAG_REQUESTED, &desc->flags); | |
107 | /* lose */ | |
108 | return -EIO; | |
109 | } | |
d2876d08 | 110 | desc_set_label(desc, "[auto]"); |
35e8bb51 DB |
111 | /* caller must chip->request() w/o spinlock */ |
112 | if (chip->request) | |
113 | return 1; | |
d2876d08 | 114 | } |
35e8bb51 | 115 | return 0; |
d2876d08 DB |
116 | } |
117 | ||
118 | /* caller holds gpio_lock *OR* gpio is marked as requested */ | |
1a2d397a | 119 | struct gpio_chip *gpio_to_chip(unsigned gpio) |
d2876d08 DB |
120 | { |
121 | return gpio_desc[gpio].chip; | |
122 | } | |
123 | ||
8d0aab2f AV |
124 | /* dynamic allocation of GPIOs, e.g. on a hotplugged device */ |
125 | static int gpiochip_find_base(int ngpio) | |
126 | { | |
127 | int i; | |
128 | int spare = 0; | |
129 | int base = -ENOSPC; | |
130 | ||
131 | for (i = ARCH_NR_GPIOS - 1; i >= 0 ; i--) { | |
169b6a7a AV |
132 | struct gpio_desc *desc = &gpio_desc[i]; |
133 | struct gpio_chip *chip = desc->chip; | |
8d0aab2f | 134 | |
169b6a7a | 135 | if (!chip && !test_bit(FLAG_RESERVED, &desc->flags)) { |
8d0aab2f AV |
136 | spare++; |
137 | if (spare == ngpio) { | |
138 | base = i; | |
139 | break; | |
140 | } | |
141 | } else { | |
142 | spare = 0; | |
169b6a7a AV |
143 | if (chip) |
144 | i -= chip->ngpio - 1; | |
8d0aab2f AV |
145 | } |
146 | } | |
147 | ||
148 | if (gpio_is_valid(base)) | |
149 | pr_debug("%s: found new base at %d\n", __func__, base); | |
150 | return base; | |
151 | } | |
152 | ||
169b6a7a AV |
153 | /** |
154 | * gpiochip_reserve() - reserve range of gpios to use with platform code only | |
155 | * @start: starting gpio number | |
156 | * @ngpio: number of gpios to reserve | |
157 | * Context: platform init, potentially before irqs or kmalloc will work | |
158 | * | |
159 | * Returns a negative errno if any gpio within the range is already reserved | |
160 | * or registered, else returns zero as a success code. Use this function | |
161 | * to mark a range of gpios as unavailable for dynamic gpio number allocation, | |
162 | * for example because its driver support is not yet loaded. | |
163 | */ | |
164 | int __init gpiochip_reserve(int start, int ngpio) | |
165 | { | |
166 | int ret = 0; | |
167 | unsigned long flags; | |
168 | int i; | |
169 | ||
bff5fda9 | 170 | if (!gpio_is_valid(start) || !gpio_is_valid(start + ngpio - 1)) |
169b6a7a AV |
171 | return -EINVAL; |
172 | ||
173 | spin_lock_irqsave(&gpio_lock, flags); | |
174 | ||
175 | for (i = start; i < start + ngpio; i++) { | |
176 | struct gpio_desc *desc = &gpio_desc[i]; | |
177 | ||
178 | if (desc->chip || test_bit(FLAG_RESERVED, &desc->flags)) { | |
179 | ret = -EBUSY; | |
180 | goto err; | |
181 | } | |
182 | ||
183 | set_bit(FLAG_RESERVED, &desc->flags); | |
184 | } | |
185 | ||
186 | pr_debug("%s: reserved gpios from %d to %d\n", | |
187 | __func__, start, start + ngpio - 1); | |
188 | err: | |
189 | spin_unlock_irqrestore(&gpio_lock, flags); | |
190 | ||
191 | return ret; | |
192 | } | |
193 | ||
d8f388d8 DB |
194 | #ifdef CONFIG_GPIO_SYSFS |
195 | ||
196 | /* lock protects against unexport_gpio() being called while | |
197 | * sysfs files are active. | |
198 | */ | |
199 | static DEFINE_MUTEX(sysfs_lock); | |
200 | ||
201 | /* | |
202 | * /sys/class/gpio/gpioN... only for GPIOs that are exported | |
203 | * /direction | |
204 | * * MAY BE OMITTED if kernel won't allow direction changes | |
205 | * * is read/write as "in" or "out" | |
206 | * * may also be written as "high" or "low", initializing | |
207 | * output value as specified ("out" implies "low") | |
208 | * /value | |
209 | * * always readable, subject to hardware behavior | |
210 | * * may be writable, as zero/nonzero | |
ff77c352 DG |
211 | * /edge |
212 | * * configures behavior of poll(2) on /value | |
213 | * * available only if pin can generate IRQs on input | |
214 | * * is read/write as "none", "falling", "rising", or "both" | |
07697461 JN |
215 | * /active_low |
216 | * * configures polarity of /value | |
217 | * * is read/write as zero/nonzero | |
218 | * * also affects existing and subsequent "falling" and "rising" | |
219 | * /edge configuration | |
d8f388d8 DB |
220 | */ |
221 | ||
222 | static ssize_t gpio_direction_show(struct device *dev, | |
223 | struct device_attribute *attr, char *buf) | |
224 | { | |
225 | const struct gpio_desc *desc = dev_get_drvdata(dev); | |
226 | ssize_t status; | |
227 | ||
228 | mutex_lock(&sysfs_lock); | |
229 | ||
230 | if (!test_bit(FLAG_EXPORT, &desc->flags)) | |
231 | status = -EIO; | |
232 | else | |
233 | status = sprintf(buf, "%s\n", | |
234 | test_bit(FLAG_IS_OUT, &desc->flags) | |
235 | ? "out" : "in"); | |
236 | ||
237 | mutex_unlock(&sysfs_lock); | |
238 | return status; | |
239 | } | |
240 | ||
241 | static ssize_t gpio_direction_store(struct device *dev, | |
242 | struct device_attribute *attr, const char *buf, size_t size) | |
243 | { | |
244 | const struct gpio_desc *desc = dev_get_drvdata(dev); | |
245 | unsigned gpio = desc - gpio_desc; | |
246 | ssize_t status; | |
247 | ||
248 | mutex_lock(&sysfs_lock); | |
249 | ||
250 | if (!test_bit(FLAG_EXPORT, &desc->flags)) | |
251 | status = -EIO; | |
252 | else if (sysfs_streq(buf, "high")) | |
253 | status = gpio_direction_output(gpio, 1); | |
254 | else if (sysfs_streq(buf, "out") || sysfs_streq(buf, "low")) | |
255 | status = gpio_direction_output(gpio, 0); | |
256 | else if (sysfs_streq(buf, "in")) | |
257 | status = gpio_direction_input(gpio); | |
258 | else | |
259 | status = -EINVAL; | |
260 | ||
261 | mutex_unlock(&sysfs_lock); | |
262 | return status ? : size; | |
263 | } | |
264 | ||
07697461 | 265 | static /* const */ DEVICE_ATTR(direction, 0644, |
d8f388d8 DB |
266 | gpio_direction_show, gpio_direction_store); |
267 | ||
268 | static ssize_t gpio_value_show(struct device *dev, | |
269 | struct device_attribute *attr, char *buf) | |
270 | { | |
271 | const struct gpio_desc *desc = dev_get_drvdata(dev); | |
272 | unsigned gpio = desc - gpio_desc; | |
273 | ssize_t status; | |
274 | ||
275 | mutex_lock(&sysfs_lock); | |
276 | ||
07697461 | 277 | if (!test_bit(FLAG_EXPORT, &desc->flags)) { |
d8f388d8 | 278 | status = -EIO; |
07697461 JN |
279 | } else { |
280 | int value; | |
281 | ||
282 | value = !!gpio_get_value_cansleep(gpio); | |
283 | if (test_bit(FLAG_ACTIVE_LOW, &desc->flags)) | |
284 | value = !value; | |
285 | ||
286 | status = sprintf(buf, "%d\n", value); | |
287 | } | |
d8f388d8 DB |
288 | |
289 | mutex_unlock(&sysfs_lock); | |
290 | return status; | |
291 | } | |
292 | ||
293 | static ssize_t gpio_value_store(struct device *dev, | |
294 | struct device_attribute *attr, const char *buf, size_t size) | |
295 | { | |
296 | const struct gpio_desc *desc = dev_get_drvdata(dev); | |
297 | unsigned gpio = desc - gpio_desc; | |
298 | ssize_t status; | |
299 | ||
300 | mutex_lock(&sysfs_lock); | |
301 | ||
302 | if (!test_bit(FLAG_EXPORT, &desc->flags)) | |
303 | status = -EIO; | |
304 | else if (!test_bit(FLAG_IS_OUT, &desc->flags)) | |
305 | status = -EPERM; | |
306 | else { | |
307 | long value; | |
308 | ||
309 | status = strict_strtol(buf, 0, &value); | |
310 | if (status == 0) { | |
07697461 JN |
311 | if (test_bit(FLAG_ACTIVE_LOW, &desc->flags)) |
312 | value = !value; | |
d8f388d8 DB |
313 | gpio_set_value_cansleep(gpio, value != 0); |
314 | status = size; | |
315 | } | |
316 | } | |
317 | ||
318 | mutex_unlock(&sysfs_lock); | |
319 | return status; | |
320 | } | |
321 | ||
07697461 | 322 | static const DEVICE_ATTR(value, 0644, |
d8f388d8 DB |
323 | gpio_value_show, gpio_value_store); |
324 | ||
ff77c352 DG |
325 | static irqreturn_t gpio_sysfs_irq(int irq, void *priv) |
326 | { | |
5ba1821d | 327 | struct sysfs_dirent *value_sd = priv; |
ff77c352 | 328 | |
5ba1821d | 329 | sysfs_notify_dirent(value_sd); |
ff77c352 DG |
330 | return IRQ_HANDLED; |
331 | } | |
332 | ||
ff77c352 DG |
333 | static int gpio_setup_irq(struct gpio_desc *desc, struct device *dev, |
334 | unsigned long gpio_flags) | |
335 | { | |
5ba1821d | 336 | struct sysfs_dirent *value_sd; |
ff77c352 DG |
337 | unsigned long irq_flags; |
338 | int ret, irq, id; | |
339 | ||
340 | if ((desc->flags & GPIO_TRIGGER_MASK) == gpio_flags) | |
341 | return 0; | |
342 | ||
343 | irq = gpio_to_irq(desc - gpio_desc); | |
344 | if (irq < 0) | |
345 | return -EIO; | |
346 | ||
5ba1821d DG |
347 | id = desc->flags >> ID_SHIFT; |
348 | value_sd = idr_find(&dirent_idr, id); | |
349 | if (value_sd) | |
350 | free_irq(irq, value_sd); | |
ff77c352 DG |
351 | |
352 | desc->flags &= ~GPIO_TRIGGER_MASK; | |
353 | ||
354 | if (!gpio_flags) { | |
355 | ret = 0; | |
5ba1821d | 356 | goto free_id; |
ff77c352 DG |
357 | } |
358 | ||
359 | irq_flags = IRQF_SHARED; | |
360 | if (test_bit(FLAG_TRIG_FALL, &gpio_flags)) | |
07697461 JN |
361 | irq_flags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ? |
362 | IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING; | |
ff77c352 | 363 | if (test_bit(FLAG_TRIG_RISE, &gpio_flags)) |
07697461 JN |
364 | irq_flags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ? |
365 | IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING; | |
ff77c352 | 366 | |
5ba1821d DG |
367 | if (!value_sd) { |
368 | value_sd = sysfs_get_dirent(dev->kobj.sd, NULL, "value"); | |
369 | if (!value_sd) { | |
370 | ret = -ENODEV; | |
ff77c352 DG |
371 | goto err_out; |
372 | } | |
373 | ||
374 | do { | |
375 | ret = -ENOMEM; | |
5ba1821d DG |
376 | if (idr_pre_get(&dirent_idr, GFP_KERNEL)) |
377 | ret = idr_get_new_above(&dirent_idr, value_sd, | |
378 | 1, &id); | |
ff77c352 DG |
379 | } while (ret == -EAGAIN); |
380 | ||
381 | if (ret) | |
5ba1821d | 382 | goto free_sd; |
ff77c352 DG |
383 | |
384 | desc->flags &= GPIO_FLAGS_MASK; | |
5ba1821d | 385 | desc->flags |= (unsigned long)id << ID_SHIFT; |
ff77c352 | 386 | |
5ba1821d | 387 | if (desc->flags >> ID_SHIFT != id) { |
ff77c352 DG |
388 | ret = -ERANGE; |
389 | goto free_id; | |
390 | } | |
ff77c352 DG |
391 | } |
392 | ||
364fadb3 | 393 | ret = request_any_context_irq(irq, gpio_sysfs_irq, irq_flags, |
5ba1821d | 394 | "gpiolib", value_sd); |
364fadb3 | 395 | if (ret < 0) |
5ba1821d | 396 | goto free_id; |
ff77c352 DG |
397 | |
398 | desc->flags |= gpio_flags; | |
399 | return 0; | |
400 | ||
ff77c352 | 401 | free_id: |
5ba1821d | 402 | idr_remove(&dirent_idr, id); |
ff77c352 | 403 | desc->flags &= GPIO_FLAGS_MASK; |
5ba1821d DG |
404 | free_sd: |
405 | if (value_sd) | |
406 | sysfs_put(value_sd); | |
ff77c352 DG |
407 | err_out: |
408 | return ret; | |
409 | } | |
410 | ||
411 | static const struct { | |
412 | const char *name; | |
413 | unsigned long flags; | |
414 | } trigger_types[] = { | |
415 | { "none", 0 }, | |
416 | { "falling", BIT(FLAG_TRIG_FALL) }, | |
417 | { "rising", BIT(FLAG_TRIG_RISE) }, | |
418 | { "both", BIT(FLAG_TRIG_FALL) | BIT(FLAG_TRIG_RISE) }, | |
419 | }; | |
420 | ||
421 | static ssize_t gpio_edge_show(struct device *dev, | |
422 | struct device_attribute *attr, char *buf) | |
423 | { | |
424 | const struct gpio_desc *desc = dev_get_drvdata(dev); | |
425 | ssize_t status; | |
426 | ||
427 | mutex_lock(&sysfs_lock); | |
428 | ||
429 | if (!test_bit(FLAG_EXPORT, &desc->flags)) | |
430 | status = -EIO; | |
431 | else { | |
432 | int i; | |
433 | ||
434 | status = 0; | |
435 | for (i = 0; i < ARRAY_SIZE(trigger_types); i++) | |
436 | if ((desc->flags & GPIO_TRIGGER_MASK) | |
437 | == trigger_types[i].flags) { | |
438 | status = sprintf(buf, "%s\n", | |
439 | trigger_types[i].name); | |
440 | break; | |
441 | } | |
442 | } | |
443 | ||
444 | mutex_unlock(&sysfs_lock); | |
445 | return status; | |
446 | } | |
447 | ||
448 | static ssize_t gpio_edge_store(struct device *dev, | |
449 | struct device_attribute *attr, const char *buf, size_t size) | |
450 | { | |
451 | struct gpio_desc *desc = dev_get_drvdata(dev); | |
452 | ssize_t status; | |
453 | int i; | |
454 | ||
455 | for (i = 0; i < ARRAY_SIZE(trigger_types); i++) | |
456 | if (sysfs_streq(trigger_types[i].name, buf)) | |
457 | goto found; | |
458 | return -EINVAL; | |
459 | ||
460 | found: | |
461 | mutex_lock(&sysfs_lock); | |
462 | ||
463 | if (!test_bit(FLAG_EXPORT, &desc->flags)) | |
464 | status = -EIO; | |
465 | else { | |
466 | status = gpio_setup_irq(desc, dev, trigger_types[i].flags); | |
467 | if (!status) | |
468 | status = size; | |
469 | } | |
470 | ||
471 | mutex_unlock(&sysfs_lock); | |
472 | ||
473 | return status; | |
474 | } | |
475 | ||
476 | static DEVICE_ATTR(edge, 0644, gpio_edge_show, gpio_edge_store); | |
477 | ||
07697461 JN |
478 | static int sysfs_set_active_low(struct gpio_desc *desc, struct device *dev, |
479 | int value) | |
480 | { | |
481 | int status = 0; | |
482 | ||
483 | if (!!test_bit(FLAG_ACTIVE_LOW, &desc->flags) == !!value) | |
484 | return 0; | |
485 | ||
486 | if (value) | |
487 | set_bit(FLAG_ACTIVE_LOW, &desc->flags); | |
488 | else | |
489 | clear_bit(FLAG_ACTIVE_LOW, &desc->flags); | |
490 | ||
491 | /* reconfigure poll(2) support if enabled on one edge only */ | |
492 | if (dev != NULL && (!!test_bit(FLAG_TRIG_RISE, &desc->flags) ^ | |
493 | !!test_bit(FLAG_TRIG_FALL, &desc->flags))) { | |
494 | unsigned long trigger_flags = desc->flags & GPIO_TRIGGER_MASK; | |
495 | ||
496 | gpio_setup_irq(desc, dev, 0); | |
497 | status = gpio_setup_irq(desc, dev, trigger_flags); | |
498 | } | |
499 | ||
500 | return status; | |
501 | } | |
502 | ||
503 | static ssize_t gpio_active_low_show(struct device *dev, | |
504 | struct device_attribute *attr, char *buf) | |
505 | { | |
506 | const struct gpio_desc *desc = dev_get_drvdata(dev); | |
507 | ssize_t status; | |
508 | ||
509 | mutex_lock(&sysfs_lock); | |
510 | ||
511 | if (!test_bit(FLAG_EXPORT, &desc->flags)) | |
512 | status = -EIO; | |
513 | else | |
514 | status = sprintf(buf, "%d\n", | |
515 | !!test_bit(FLAG_ACTIVE_LOW, &desc->flags)); | |
516 | ||
517 | mutex_unlock(&sysfs_lock); | |
518 | ||
519 | return status; | |
520 | } | |
521 | ||
522 | static ssize_t gpio_active_low_store(struct device *dev, | |
523 | struct device_attribute *attr, const char *buf, size_t size) | |
524 | { | |
525 | struct gpio_desc *desc = dev_get_drvdata(dev); | |
526 | ssize_t status; | |
527 | ||
528 | mutex_lock(&sysfs_lock); | |
529 | ||
530 | if (!test_bit(FLAG_EXPORT, &desc->flags)) { | |
531 | status = -EIO; | |
532 | } else { | |
533 | long value; | |
534 | ||
535 | status = strict_strtol(buf, 0, &value); | |
536 | if (status == 0) | |
537 | status = sysfs_set_active_low(desc, dev, value != 0); | |
538 | } | |
539 | ||
540 | mutex_unlock(&sysfs_lock); | |
541 | ||
542 | return status ? : size; | |
543 | } | |
544 | ||
545 | static const DEVICE_ATTR(active_low, 0644, | |
546 | gpio_active_low_show, gpio_active_low_store); | |
547 | ||
d8f388d8 | 548 | static const struct attribute *gpio_attrs[] = { |
d8f388d8 | 549 | &dev_attr_value.attr, |
07697461 | 550 | &dev_attr_active_low.attr, |
d8f388d8 DB |
551 | NULL, |
552 | }; | |
553 | ||
554 | static const struct attribute_group gpio_attr_group = { | |
555 | .attrs = (struct attribute **) gpio_attrs, | |
556 | }; | |
557 | ||
558 | /* | |
559 | * /sys/class/gpio/gpiochipN/ | |
560 | * /base ... matching gpio_chip.base (N) | |
561 | * /label ... matching gpio_chip.label | |
562 | * /ngpio ... matching gpio_chip.ngpio | |
563 | */ | |
564 | ||
565 | static ssize_t chip_base_show(struct device *dev, | |
566 | struct device_attribute *attr, char *buf) | |
567 | { | |
568 | const struct gpio_chip *chip = dev_get_drvdata(dev); | |
569 | ||
570 | return sprintf(buf, "%d\n", chip->base); | |
571 | } | |
572 | static DEVICE_ATTR(base, 0444, chip_base_show, NULL); | |
573 | ||
574 | static ssize_t chip_label_show(struct device *dev, | |
575 | struct device_attribute *attr, char *buf) | |
576 | { | |
577 | const struct gpio_chip *chip = dev_get_drvdata(dev); | |
578 | ||
579 | return sprintf(buf, "%s\n", chip->label ? : ""); | |
580 | } | |
581 | static DEVICE_ATTR(label, 0444, chip_label_show, NULL); | |
582 | ||
583 | static ssize_t chip_ngpio_show(struct device *dev, | |
584 | struct device_attribute *attr, char *buf) | |
585 | { | |
586 | const struct gpio_chip *chip = dev_get_drvdata(dev); | |
587 | ||
588 | return sprintf(buf, "%u\n", chip->ngpio); | |
589 | } | |
590 | static DEVICE_ATTR(ngpio, 0444, chip_ngpio_show, NULL); | |
591 | ||
592 | static const struct attribute *gpiochip_attrs[] = { | |
593 | &dev_attr_base.attr, | |
594 | &dev_attr_label.attr, | |
595 | &dev_attr_ngpio.attr, | |
596 | NULL, | |
597 | }; | |
598 | ||
599 | static const struct attribute_group gpiochip_attr_group = { | |
600 | .attrs = (struct attribute **) gpiochip_attrs, | |
601 | }; | |
602 | ||
603 | /* | |
604 | * /sys/class/gpio/export ... write-only | |
605 | * integer N ... number of GPIO to export (full access) | |
606 | * /sys/class/gpio/unexport ... write-only | |
607 | * integer N ... number of GPIO to unexport | |
608 | */ | |
28812fe1 AK |
609 | static ssize_t export_store(struct class *class, |
610 | struct class_attribute *attr, | |
611 | const char *buf, size_t len) | |
d8f388d8 DB |
612 | { |
613 | long gpio; | |
614 | int status; | |
615 | ||
616 | status = strict_strtol(buf, 0, &gpio); | |
617 | if (status < 0) | |
618 | goto done; | |
619 | ||
620 | /* No extra locking here; FLAG_SYSFS just signifies that the | |
621 | * request and export were done by on behalf of userspace, so | |
622 | * they may be undone on its behalf too. | |
623 | */ | |
624 | ||
625 | status = gpio_request(gpio, "sysfs"); | |
626 | if (status < 0) | |
627 | goto done; | |
628 | ||
629 | status = gpio_export(gpio, true); | |
630 | if (status < 0) | |
631 | gpio_free(gpio); | |
632 | else | |
633 | set_bit(FLAG_SYSFS, &gpio_desc[gpio].flags); | |
634 | ||
635 | done: | |
636 | if (status) | |
637 | pr_debug("%s: status %d\n", __func__, status); | |
638 | return status ? : len; | |
639 | } | |
640 | ||
28812fe1 AK |
641 | static ssize_t unexport_store(struct class *class, |
642 | struct class_attribute *attr, | |
643 | const char *buf, size_t len) | |
d8f388d8 DB |
644 | { |
645 | long gpio; | |
646 | int status; | |
647 | ||
648 | status = strict_strtol(buf, 0, &gpio); | |
649 | if (status < 0) | |
650 | goto done; | |
651 | ||
652 | status = -EINVAL; | |
653 | ||
654 | /* reject bogus commands (gpio_unexport ignores them) */ | |
655 | if (!gpio_is_valid(gpio)) | |
656 | goto done; | |
657 | ||
658 | /* No extra locking here; FLAG_SYSFS just signifies that the | |
659 | * request and export were done by on behalf of userspace, so | |
660 | * they may be undone on its behalf too. | |
661 | */ | |
662 | if (test_and_clear_bit(FLAG_SYSFS, &gpio_desc[gpio].flags)) { | |
663 | status = 0; | |
664 | gpio_free(gpio); | |
665 | } | |
666 | done: | |
667 | if (status) | |
668 | pr_debug("%s: status %d\n", __func__, status); | |
669 | return status ? : len; | |
670 | } | |
671 | ||
672 | static struct class_attribute gpio_class_attrs[] = { | |
673 | __ATTR(export, 0200, NULL, export_store), | |
674 | __ATTR(unexport, 0200, NULL, unexport_store), | |
675 | __ATTR_NULL, | |
676 | }; | |
677 | ||
678 | static struct class gpio_class = { | |
679 | .name = "gpio", | |
680 | .owner = THIS_MODULE, | |
681 | ||
682 | .class_attrs = gpio_class_attrs, | |
683 | }; | |
684 | ||
685 | ||
686 | /** | |
687 | * gpio_export - export a GPIO through sysfs | |
688 | * @gpio: gpio to make available, already requested | |
689 | * @direction_may_change: true if userspace may change gpio direction | |
690 | * Context: arch_initcall or later | |
691 | * | |
692 | * When drivers want to make a GPIO accessible to userspace after they | |
693 | * have requested it -- perhaps while debugging, or as part of their | |
694 | * public interface -- they may use this routine. If the GPIO can | |
695 | * change direction (some can't) and the caller allows it, userspace | |
696 | * will see "direction" sysfs attribute which may be used to change | |
697 | * the gpio's direction. A "value" attribute will always be provided. | |
698 | * | |
699 | * Returns zero on success, else an error. | |
700 | */ | |
701 | int gpio_export(unsigned gpio, bool direction_may_change) | |
702 | { | |
703 | unsigned long flags; | |
704 | struct gpio_desc *desc; | |
fc4e2514 | 705 | int status; |
62154991 | 706 | const char *ioname = NULL; |
fc4e2514 | 707 | struct device *dev; |
d8f388d8 DB |
708 | |
709 | /* can't export until sysfs is available ... */ | |
710 | if (!gpio_class.p) { | |
711 | pr_debug("%s: called too early!\n", __func__); | |
712 | return -ENOENT; | |
713 | } | |
714 | ||
fc4e2514 RM |
715 | if (!gpio_is_valid(gpio)) { |
716 | pr_debug("%s: gpio %d is not valid\n", __func__, gpio); | |
717 | return -EINVAL; | |
718 | } | |
d8f388d8 DB |
719 | |
720 | mutex_lock(&sysfs_lock); | |
721 | ||
722 | spin_lock_irqsave(&gpio_lock, flags); | |
723 | desc = &gpio_desc[gpio]; | |
fc4e2514 RM |
724 | if (!test_bit(FLAG_REQUESTED, &desc->flags) || |
725 | test_bit(FLAG_EXPORT, &desc->flags)) { | |
726 | spin_unlock_irqrestore(&gpio_lock, flags); | |
727 | pr_debug("%s: gpio %d unavailable (requested=%d, exported=%d)\n", | |
728 | __func__, gpio, | |
729 | test_bit(FLAG_REQUESTED, &desc->flags), | |
730 | test_bit(FLAG_EXPORT, &desc->flags)); | |
731 | return -EPERM; | |
d8f388d8 | 732 | } |
fc4e2514 RM |
733 | |
734 | if (!desc->chip->direction_input || !desc->chip->direction_output) | |
735 | direction_may_change = false; | |
d8f388d8 DB |
736 | spin_unlock_irqrestore(&gpio_lock, flags); |
737 | ||
926b663c DS |
738 | if (desc->chip->names && desc->chip->names[gpio - desc->chip->base]) |
739 | ioname = desc->chip->names[gpio - desc->chip->base]; | |
740 | ||
fc4e2514 RM |
741 | dev = device_create(&gpio_class, desc->chip->dev, MKDEV(0, 0), |
742 | desc, ioname ? ioname : "gpio%u", gpio); | |
743 | if (IS_ERR(dev)) { | |
744 | status = PTR_ERR(dev); | |
745 | goto fail_unlock; | |
d8f388d8 DB |
746 | } |
747 | ||
fc4e2514 | 748 | status = sysfs_create_group(&dev->kobj, &gpio_attr_group); |
d8f388d8 | 749 | if (status) |
fc4e2514 RM |
750 | goto fail_unregister_device; |
751 | ||
752 | if (direction_may_change) { | |
753 | status = device_create_file(dev, &dev_attr_direction); | |
754 | if (status) | |
755 | goto fail_unregister_device; | |
756 | } | |
757 | ||
758 | if (gpio_to_irq(gpio) >= 0 && (direction_may_change || | |
759 | !test_bit(FLAG_IS_OUT, &desc->flags))) { | |
760 | status = device_create_file(dev, &dev_attr_edge); | |
761 | if (status) | |
762 | goto fail_unregister_device; | |
763 | } | |
d8f388d8 | 764 | |
fc4e2514 RM |
765 | set_bit(FLAG_EXPORT, &desc->flags); |
766 | mutex_unlock(&sysfs_lock); | |
767 | return 0; | |
768 | ||
769 | fail_unregister_device: | |
770 | device_unregister(dev); | |
771 | fail_unlock: | |
772 | mutex_unlock(&sysfs_lock); | |
773 | pr_debug("%s: gpio%d status %d\n", __func__, gpio, status); | |
d8f388d8 DB |
774 | return status; |
775 | } | |
776 | EXPORT_SYMBOL_GPL(gpio_export); | |
777 | ||
778 | static int match_export(struct device *dev, void *data) | |
779 | { | |
780 | return dev_get_drvdata(dev) == data; | |
781 | } | |
782 | ||
a4177ee7 JN |
783 | /** |
784 | * gpio_export_link - create a sysfs link to an exported GPIO node | |
785 | * @dev: device under which to create symlink | |
786 | * @name: name of the symlink | |
787 | * @gpio: gpio to create symlink to, already exported | |
788 | * | |
789 | * Set up a symlink from /sys/.../dev/name to /sys/class/gpio/gpioN | |
790 | * node. Caller is responsible for unlinking. | |
791 | * | |
792 | * Returns zero on success, else an error. | |
793 | */ | |
794 | int gpio_export_link(struct device *dev, const char *name, unsigned gpio) | |
795 | { | |
796 | struct gpio_desc *desc; | |
797 | int status = -EINVAL; | |
798 | ||
799 | if (!gpio_is_valid(gpio)) | |
800 | goto done; | |
801 | ||
802 | mutex_lock(&sysfs_lock); | |
803 | ||
804 | desc = &gpio_desc[gpio]; | |
805 | ||
806 | if (test_bit(FLAG_EXPORT, &desc->flags)) { | |
807 | struct device *tdev; | |
808 | ||
809 | tdev = class_find_device(&gpio_class, NULL, desc, match_export); | |
810 | if (tdev != NULL) { | |
811 | status = sysfs_create_link(&dev->kobj, &tdev->kobj, | |
812 | name); | |
813 | } else { | |
814 | status = -ENODEV; | |
815 | } | |
816 | } | |
817 | ||
818 | mutex_unlock(&sysfs_lock); | |
819 | ||
820 | done: | |
821 | if (status) | |
822 | pr_debug("%s: gpio%d status %d\n", __func__, gpio, status); | |
823 | ||
824 | return status; | |
825 | } | |
826 | EXPORT_SYMBOL_GPL(gpio_export_link); | |
827 | ||
07697461 JN |
828 | |
829 | /** | |
830 | * gpio_sysfs_set_active_low - set the polarity of gpio sysfs value | |
831 | * @gpio: gpio to change | |
832 | * @value: non-zero to use active low, i.e. inverted values | |
833 | * | |
834 | * Set the polarity of /sys/class/gpio/gpioN/value sysfs attribute. | |
835 | * The GPIO does not have to be exported yet. If poll(2) support has | |
836 | * been enabled for either rising or falling edge, it will be | |
837 | * reconfigured to follow the new polarity. | |
838 | * | |
839 | * Returns zero on success, else an error. | |
840 | */ | |
841 | int gpio_sysfs_set_active_low(unsigned gpio, int value) | |
842 | { | |
843 | struct gpio_desc *desc; | |
844 | struct device *dev = NULL; | |
845 | int status = -EINVAL; | |
846 | ||
847 | if (!gpio_is_valid(gpio)) | |
848 | goto done; | |
849 | ||
850 | mutex_lock(&sysfs_lock); | |
851 | ||
852 | desc = &gpio_desc[gpio]; | |
853 | ||
854 | if (test_bit(FLAG_EXPORT, &desc->flags)) { | |
07697461 JN |
855 | dev = class_find_device(&gpio_class, NULL, desc, match_export); |
856 | if (dev == NULL) { | |
857 | status = -ENODEV; | |
858 | goto unlock; | |
859 | } | |
860 | } | |
861 | ||
862 | status = sysfs_set_active_low(desc, dev, value); | |
863 | ||
864 | unlock: | |
865 | mutex_unlock(&sysfs_lock); | |
866 | ||
867 | done: | |
868 | if (status) | |
869 | pr_debug("%s: gpio%d status %d\n", __func__, gpio, status); | |
870 | ||
871 | return status; | |
872 | } | |
873 | EXPORT_SYMBOL_GPL(gpio_sysfs_set_active_low); | |
874 | ||
d8f388d8 DB |
875 | /** |
876 | * gpio_unexport - reverse effect of gpio_export() | |
877 | * @gpio: gpio to make unavailable | |
878 | * | |
879 | * This is implicit on gpio_free(). | |
880 | */ | |
881 | void gpio_unexport(unsigned gpio) | |
882 | { | |
883 | struct gpio_desc *desc; | |
6a99ad4a | 884 | int status = 0; |
864533ce | 885 | struct device *dev = NULL; |
d8f388d8 | 886 | |
6a99ad4a JP |
887 | if (!gpio_is_valid(gpio)) { |
888 | status = -EINVAL; | |
d8f388d8 | 889 | goto done; |
6a99ad4a | 890 | } |
d8f388d8 DB |
891 | |
892 | mutex_lock(&sysfs_lock); | |
893 | ||
894 | desc = &gpio_desc[gpio]; | |
926b663c | 895 | |
d8f388d8 | 896 | if (test_bit(FLAG_EXPORT, &desc->flags)) { |
d8f388d8 DB |
897 | |
898 | dev = class_find_device(&gpio_class, NULL, desc, match_export); | |
899 | if (dev) { | |
ff77c352 | 900 | gpio_setup_irq(desc, dev, 0); |
d8f388d8 | 901 | clear_bit(FLAG_EXPORT, &desc->flags); |
d8f388d8 DB |
902 | } else |
903 | status = -ENODEV; | |
904 | } | |
905 | ||
906 | mutex_unlock(&sysfs_lock); | |
864533ce ML |
907 | if (dev) { |
908 | device_unregister(dev); | |
909 | put_device(dev); | |
910 | } | |
d8f388d8 DB |
911 | done: |
912 | if (status) | |
913 | pr_debug("%s: gpio%d status %d\n", __func__, gpio, status); | |
914 | } | |
915 | EXPORT_SYMBOL_GPL(gpio_unexport); | |
916 | ||
917 | static int gpiochip_export(struct gpio_chip *chip) | |
918 | { | |
919 | int status; | |
920 | struct device *dev; | |
921 | ||
922 | /* Many systems register gpio chips for SOC support very early, | |
923 | * before driver model support is available. In those cases we | |
924 | * export this later, in gpiolib_sysfs_init() ... here we just | |
925 | * verify that _some_ field of gpio_class got initialized. | |
926 | */ | |
927 | if (!gpio_class.p) | |
928 | return 0; | |
929 | ||
930 | /* use chip->base for the ID; it's already known to be unique */ | |
931 | mutex_lock(&sysfs_lock); | |
932 | dev = device_create(&gpio_class, chip->dev, MKDEV(0, 0), chip, | |
933 | "gpiochip%d", chip->base); | |
d62668e1 | 934 | if (!IS_ERR(dev)) { |
d8f388d8 DB |
935 | status = sysfs_create_group(&dev->kobj, |
936 | &gpiochip_attr_group); | |
937 | } else | |
d62668e1 | 938 | status = PTR_ERR(dev); |
d8f388d8 DB |
939 | chip->exported = (status == 0); |
940 | mutex_unlock(&sysfs_lock); | |
941 | ||
942 | if (status) { | |
943 | unsigned long flags; | |
944 | unsigned gpio; | |
945 | ||
946 | spin_lock_irqsave(&gpio_lock, flags); | |
947 | gpio = chip->base; | |
948 | while (gpio_desc[gpio].chip == chip) | |
949 | gpio_desc[gpio++].chip = NULL; | |
950 | spin_unlock_irqrestore(&gpio_lock, flags); | |
951 | ||
952 | pr_debug("%s: chip %s status %d\n", __func__, | |
953 | chip->label, status); | |
954 | } | |
955 | ||
956 | return status; | |
957 | } | |
958 | ||
959 | static void gpiochip_unexport(struct gpio_chip *chip) | |
960 | { | |
961 | int status; | |
962 | struct device *dev; | |
963 | ||
964 | mutex_lock(&sysfs_lock); | |
965 | dev = class_find_device(&gpio_class, NULL, chip, match_export); | |
966 | if (dev) { | |
967 | put_device(dev); | |
968 | device_unregister(dev); | |
969 | chip->exported = 0; | |
970 | status = 0; | |
971 | } else | |
972 | status = -ENODEV; | |
973 | mutex_unlock(&sysfs_lock); | |
974 | ||
975 | if (status) | |
976 | pr_debug("%s: chip %s status %d\n", __func__, | |
977 | chip->label, status); | |
978 | } | |
979 | ||
980 | static int __init gpiolib_sysfs_init(void) | |
981 | { | |
982 | int status; | |
983 | unsigned long flags; | |
984 | unsigned gpio; | |
985 | ||
986 | status = class_register(&gpio_class); | |
987 | if (status < 0) | |
988 | return status; | |
989 | ||
990 | /* Scan and register the gpio_chips which registered very | |
991 | * early (e.g. before the class_register above was called). | |
992 | * | |
993 | * We run before arch_initcall() so chip->dev nodes can have | |
994 | * registered, and so arch_initcall() can always gpio_export(). | |
995 | */ | |
996 | spin_lock_irqsave(&gpio_lock, flags); | |
997 | for (gpio = 0; gpio < ARCH_NR_GPIOS; gpio++) { | |
998 | struct gpio_chip *chip; | |
999 | ||
1000 | chip = gpio_desc[gpio].chip; | |
1001 | if (!chip || chip->exported) | |
1002 | continue; | |
1003 | ||
1004 | spin_unlock_irqrestore(&gpio_lock, flags); | |
1005 | status = gpiochip_export(chip); | |
1006 | spin_lock_irqsave(&gpio_lock, flags); | |
1007 | } | |
1008 | spin_unlock_irqrestore(&gpio_lock, flags); | |
1009 | ||
1010 | ||
1011 | return status; | |
1012 | } | |
1013 | postcore_initcall(gpiolib_sysfs_init); | |
1014 | ||
1015 | #else | |
1016 | static inline int gpiochip_export(struct gpio_chip *chip) | |
1017 | { | |
1018 | return 0; | |
1019 | } | |
1020 | ||
1021 | static inline void gpiochip_unexport(struct gpio_chip *chip) | |
1022 | { | |
1023 | } | |
1024 | ||
1025 | #endif /* CONFIG_GPIO_SYSFS */ | |
1026 | ||
d2876d08 DB |
1027 | /** |
1028 | * gpiochip_add() - register a gpio_chip | |
1029 | * @chip: the chip to register, with chip->base initialized | |
1030 | * Context: potentially before irqs or kmalloc will work | |
1031 | * | |
1032 | * Returns a negative errno if the chip can't be registered, such as | |
1033 | * because the chip->base is invalid or already associated with a | |
1034 | * different chip. Otherwise it returns zero as a success code. | |
8d0aab2f | 1035 | * |
d8f388d8 DB |
1036 | * When gpiochip_add() is called very early during boot, so that GPIOs |
1037 | * can be freely used, the chip->dev device must be registered before | |
1038 | * the gpio framework's arch_initcall(). Otherwise sysfs initialization | |
1039 | * for GPIOs will fail rudely. | |
1040 | * | |
8d0aab2f AV |
1041 | * If chip->base is negative, this requests dynamic assignment of |
1042 | * a range of valid GPIOs. | |
d2876d08 DB |
1043 | */ |
1044 | int gpiochip_add(struct gpio_chip *chip) | |
1045 | { | |
1046 | unsigned long flags; | |
1047 | int status = 0; | |
1048 | unsigned id; | |
8d0aab2f | 1049 | int base = chip->base; |
d2876d08 | 1050 | |
bff5fda9 | 1051 | if ((!gpio_is_valid(base) || !gpio_is_valid(base + chip->ngpio - 1)) |
8d0aab2f | 1052 | && base >= 0) { |
d2876d08 DB |
1053 | status = -EINVAL; |
1054 | goto fail; | |
1055 | } | |
1056 | ||
1057 | spin_lock_irqsave(&gpio_lock, flags); | |
1058 | ||
8d0aab2f AV |
1059 | if (base < 0) { |
1060 | base = gpiochip_find_base(chip->ngpio); | |
1061 | if (base < 0) { | |
1062 | status = base; | |
d8f388d8 | 1063 | goto unlock; |
8d0aab2f AV |
1064 | } |
1065 | chip->base = base; | |
1066 | } | |
1067 | ||
d2876d08 | 1068 | /* these GPIO numbers must not be managed by another gpio_chip */ |
8d0aab2f | 1069 | for (id = base; id < base + chip->ngpio; id++) { |
d2876d08 DB |
1070 | if (gpio_desc[id].chip != NULL) { |
1071 | status = -EBUSY; | |
1072 | break; | |
1073 | } | |
1074 | } | |
1075 | if (status == 0) { | |
8d0aab2f | 1076 | for (id = base; id < base + chip->ngpio; id++) { |
d2876d08 | 1077 | gpio_desc[id].chip = chip; |
d8f388d8 DB |
1078 | |
1079 | /* REVISIT: most hardware initializes GPIOs as | |
1080 | * inputs (often with pullups enabled) so power | |
1081 | * usage is minimized. Linux code should set the | |
1082 | * gpio direction first thing; but until it does, | |
1083 | * we may expose the wrong direction in sysfs. | |
1084 | */ | |
1085 | gpio_desc[id].flags = !chip->direction_input | |
1086 | ? (1 << FLAG_IS_OUT) | |
1087 | : 0; | |
d2876d08 DB |
1088 | } |
1089 | } | |
1090 | ||
391c970c AV |
1091 | of_gpiochip_add(chip); |
1092 | ||
d8f388d8 | 1093 | unlock: |
d2876d08 | 1094 | spin_unlock_irqrestore(&gpio_lock, flags); |
cedb1881 AV |
1095 | |
1096 | if (status) | |
1097 | goto fail; | |
1098 | ||
1099 | status = gpiochip_export(chip); | |
1100 | if (status) | |
1101 | goto fail; | |
1102 | ||
ee1c1e7d | 1103 | pr_debug("gpiochip_add: registered GPIOs %d to %d on device: %s\n", |
64842aad GL |
1104 | chip->base, chip->base + chip->ngpio - 1, |
1105 | chip->label ? : "generic"); | |
1106 | ||
cedb1881 | 1107 | return 0; |
d2876d08 DB |
1108 | fail: |
1109 | /* failures here can mean systems won't boot... */ | |
cedb1881 AV |
1110 | pr_err("gpiochip_add: gpios %d..%d (%s) failed to register\n", |
1111 | chip->base, chip->base + chip->ngpio - 1, | |
1112 | chip->label ? : "generic"); | |
d2876d08 DB |
1113 | return status; |
1114 | } | |
1115 | EXPORT_SYMBOL_GPL(gpiochip_add); | |
1116 | ||
1117 | /** | |
1118 | * gpiochip_remove() - unregister a gpio_chip | |
1119 | * @chip: the chip to unregister | |
1120 | * | |
1121 | * A gpio_chip with any GPIOs still requested may not be removed. | |
1122 | */ | |
1123 | int gpiochip_remove(struct gpio_chip *chip) | |
1124 | { | |
1125 | unsigned long flags; | |
1126 | int status = 0; | |
1127 | unsigned id; | |
1128 | ||
1129 | spin_lock_irqsave(&gpio_lock, flags); | |
1130 | ||
391c970c AV |
1131 | of_gpiochip_remove(chip); |
1132 | ||
d2876d08 DB |
1133 | for (id = chip->base; id < chip->base + chip->ngpio; id++) { |
1134 | if (test_bit(FLAG_REQUESTED, &gpio_desc[id].flags)) { | |
1135 | status = -EBUSY; | |
1136 | break; | |
1137 | } | |
1138 | } | |
1139 | if (status == 0) { | |
1140 | for (id = chip->base; id < chip->base + chip->ngpio; id++) | |
1141 | gpio_desc[id].chip = NULL; | |
1142 | } | |
1143 | ||
1144 | spin_unlock_irqrestore(&gpio_lock, flags); | |
d8f388d8 DB |
1145 | |
1146 | if (status == 0) | |
1147 | gpiochip_unexport(chip); | |
1148 | ||
d2876d08 DB |
1149 | return status; |
1150 | } | |
1151 | EXPORT_SYMBOL_GPL(gpiochip_remove); | |
1152 | ||
594fa265 GL |
1153 | /** |
1154 | * gpiochip_find() - iterator for locating a specific gpio_chip | |
1155 | * @data: data to pass to match function | |
1156 | * @callback: Callback function to check gpio_chip | |
1157 | * | |
1158 | * Similar to bus_find_device. It returns a reference to a gpio_chip as | |
1159 | * determined by a user supplied @match callback. The callback should return | |
1160 | * 0 if the device doesn't match and non-zero if it does. If the callback is | |
1161 | * non-zero, this function will return to the caller and not iterate over any | |
1162 | * more gpio_chips. | |
1163 | */ | |
07ce8ec7 | 1164 | struct gpio_chip *gpiochip_find(void *data, |
6e2cf651 | 1165 | int (*match)(struct gpio_chip *chip, |
3d0f7cf0 | 1166 | void *data)) |
594fa265 GL |
1167 | { |
1168 | struct gpio_chip *chip = NULL; | |
1169 | unsigned long flags; | |
1170 | int i; | |
1171 | ||
1172 | spin_lock_irqsave(&gpio_lock, flags); | |
1173 | for (i = 0; i < ARCH_NR_GPIOS; i++) { | |
1174 | if (!gpio_desc[i].chip) | |
1175 | continue; | |
1176 | ||
1177 | if (match(gpio_desc[i].chip, data)) { | |
1178 | chip = gpio_desc[i].chip; | |
1179 | break; | |
1180 | } | |
1181 | } | |
1182 | spin_unlock_irqrestore(&gpio_lock, flags); | |
1183 | ||
1184 | return chip; | |
1185 | } | |
8fa0c9bf | 1186 | EXPORT_SYMBOL_GPL(gpiochip_find); |
d2876d08 DB |
1187 | |
1188 | /* These "optional" allocation calls help prevent drivers from stomping | |
1189 | * on each other, and help provide better diagnostics in debugfs. | |
1190 | * They're called even less than the "set direction" calls. | |
1191 | */ | |
1192 | int gpio_request(unsigned gpio, const char *label) | |
1193 | { | |
1194 | struct gpio_desc *desc; | |
35e8bb51 | 1195 | struct gpio_chip *chip; |
e9354576 | 1196 | int status = -EPROBE_DEFER; |
d2876d08 DB |
1197 | unsigned long flags; |
1198 | ||
1199 | spin_lock_irqsave(&gpio_lock, flags); | |
1200 | ||
e6de1808 | 1201 | if (!gpio_is_valid(gpio)) |
d2876d08 DB |
1202 | goto done; |
1203 | desc = &gpio_desc[gpio]; | |
35e8bb51 DB |
1204 | chip = desc->chip; |
1205 | if (chip == NULL) | |
d2876d08 DB |
1206 | goto done; |
1207 | ||
35e8bb51 | 1208 | if (!try_module_get(chip->owner)) |
438d8908 GL |
1209 | goto done; |
1210 | ||
d2876d08 | 1211 | /* NOTE: gpio_request() can be called in early boot, |
35e8bb51 | 1212 | * before IRQs are enabled, for non-sleeping (SOC) GPIOs. |
d2876d08 DB |
1213 | */ |
1214 | ||
1215 | if (test_and_set_bit(FLAG_REQUESTED, &desc->flags) == 0) { | |
1216 | desc_set_label(desc, label ? : "?"); | |
1217 | status = 0; | |
438d8908 | 1218 | } else { |
d2876d08 | 1219 | status = -EBUSY; |
35e8bb51 | 1220 | module_put(chip->owner); |
7460db56 | 1221 | goto done; |
35e8bb51 DB |
1222 | } |
1223 | ||
1224 | if (chip->request) { | |
1225 | /* chip->request may sleep */ | |
1226 | spin_unlock_irqrestore(&gpio_lock, flags); | |
1227 | status = chip->request(chip, gpio - chip->base); | |
1228 | spin_lock_irqsave(&gpio_lock, flags); | |
1229 | ||
1230 | if (status < 0) { | |
1231 | desc_set_label(desc, NULL); | |
1232 | module_put(chip->owner); | |
1233 | clear_bit(FLAG_REQUESTED, &desc->flags); | |
1234 | } | |
438d8908 | 1235 | } |
d2876d08 DB |
1236 | |
1237 | done: | |
1238 | if (status) | |
1239 | pr_debug("gpio_request: gpio-%d (%s) status %d\n", | |
1240 | gpio, label ? : "?", status); | |
1241 | spin_unlock_irqrestore(&gpio_lock, flags); | |
1242 | return status; | |
1243 | } | |
1244 | EXPORT_SYMBOL_GPL(gpio_request); | |
1245 | ||
1246 | void gpio_free(unsigned gpio) | |
1247 | { | |
1248 | unsigned long flags; | |
1249 | struct gpio_desc *desc; | |
35e8bb51 | 1250 | struct gpio_chip *chip; |
d2876d08 | 1251 | |
3d599d1c UKK |
1252 | might_sleep(); |
1253 | ||
e6de1808 | 1254 | if (!gpio_is_valid(gpio)) { |
d2876d08 DB |
1255 | WARN_ON(extra_checks); |
1256 | return; | |
1257 | } | |
1258 | ||
d8f388d8 DB |
1259 | gpio_unexport(gpio); |
1260 | ||
d2876d08 DB |
1261 | spin_lock_irqsave(&gpio_lock, flags); |
1262 | ||
1263 | desc = &gpio_desc[gpio]; | |
35e8bb51 DB |
1264 | chip = desc->chip; |
1265 | if (chip && test_bit(FLAG_REQUESTED, &desc->flags)) { | |
1266 | if (chip->free) { | |
1267 | spin_unlock_irqrestore(&gpio_lock, flags); | |
9c4ba946 | 1268 | might_sleep_if(chip->can_sleep); |
35e8bb51 DB |
1269 | chip->free(chip, gpio - chip->base); |
1270 | spin_lock_irqsave(&gpio_lock, flags); | |
1271 | } | |
d2876d08 | 1272 | desc_set_label(desc, NULL); |
438d8908 | 1273 | module_put(desc->chip->owner); |
07697461 | 1274 | clear_bit(FLAG_ACTIVE_LOW, &desc->flags); |
35e8bb51 | 1275 | clear_bit(FLAG_REQUESTED, &desc->flags); |
aca5ce14 | 1276 | clear_bit(FLAG_OPEN_DRAIN, &desc->flags); |
25553ff0 | 1277 | clear_bit(FLAG_OPEN_SOURCE, &desc->flags); |
438d8908 | 1278 | } else |
d2876d08 DB |
1279 | WARN_ON(extra_checks); |
1280 | ||
1281 | spin_unlock_irqrestore(&gpio_lock, flags); | |
1282 | } | |
1283 | EXPORT_SYMBOL_GPL(gpio_free); | |
1284 | ||
3e45f1d1 EM |
1285 | /** |
1286 | * gpio_request_one - request a single GPIO with initial configuration | |
1287 | * @gpio: the GPIO number | |
1288 | * @flags: GPIO configuration as specified by GPIOF_* | |
1289 | * @label: a literal description string of this GPIO | |
1290 | */ | |
1291 | int gpio_request_one(unsigned gpio, unsigned long flags, const char *label) | |
1292 | { | |
1293 | int err; | |
1294 | ||
1295 | err = gpio_request(gpio, label); | |
1296 | if (err) | |
1297 | return err; | |
1298 | ||
aca5ce14 LD |
1299 | if (flags & GPIOF_OPEN_DRAIN) |
1300 | set_bit(FLAG_OPEN_DRAIN, &gpio_desc[gpio].flags); | |
1301 | ||
25553ff0 LD |
1302 | if (flags & GPIOF_OPEN_SOURCE) |
1303 | set_bit(FLAG_OPEN_SOURCE, &gpio_desc[gpio].flags); | |
1304 | ||
3e45f1d1 EM |
1305 | if (flags & GPIOF_DIR_IN) |
1306 | err = gpio_direction_input(gpio); | |
1307 | else | |
1308 | err = gpio_direction_output(gpio, | |
1309 | (flags & GPIOF_INIT_HIGH) ? 1 : 0); | |
1310 | ||
e254811c | 1311 | if (err) |
fc3a1f04 WS |
1312 | goto free_gpio; |
1313 | ||
1314 | if (flags & GPIOF_EXPORT) { | |
1315 | err = gpio_export(gpio, flags & GPIOF_EXPORT_CHANGEABLE); | |
1316 | if (err) | |
1317 | goto free_gpio; | |
1318 | } | |
1319 | ||
1320 | return 0; | |
e254811c | 1321 | |
fc3a1f04 WS |
1322 | free_gpio: |
1323 | gpio_free(gpio); | |
3e45f1d1 EM |
1324 | return err; |
1325 | } | |
1326 | EXPORT_SYMBOL_GPL(gpio_request_one); | |
1327 | ||
1328 | /** | |
1329 | * gpio_request_array - request multiple GPIOs in a single call | |
1330 | * @array: array of the 'struct gpio' | |
1331 | * @num: how many GPIOs in the array | |
1332 | */ | |
7c295975 | 1333 | int gpio_request_array(const struct gpio *array, size_t num) |
3e45f1d1 EM |
1334 | { |
1335 | int i, err; | |
1336 | ||
1337 | for (i = 0; i < num; i++, array++) { | |
1338 | err = gpio_request_one(array->gpio, array->flags, array->label); | |
1339 | if (err) | |
1340 | goto err_free; | |
1341 | } | |
1342 | return 0; | |
1343 | ||
1344 | err_free: | |
1345 | while (i--) | |
1346 | gpio_free((--array)->gpio); | |
1347 | return err; | |
1348 | } | |
1349 | EXPORT_SYMBOL_GPL(gpio_request_array); | |
1350 | ||
1351 | /** | |
1352 | * gpio_free_array - release multiple GPIOs in a single call | |
1353 | * @array: array of the 'struct gpio' | |
1354 | * @num: how many GPIOs in the array | |
1355 | */ | |
7c295975 | 1356 | void gpio_free_array(const struct gpio *array, size_t num) |
3e45f1d1 EM |
1357 | { |
1358 | while (num--) | |
1359 | gpio_free((array++)->gpio); | |
1360 | } | |
1361 | EXPORT_SYMBOL_GPL(gpio_free_array); | |
d2876d08 DB |
1362 | |
1363 | /** | |
1364 | * gpiochip_is_requested - return string iff signal was requested | |
1365 | * @chip: controller managing the signal | |
1366 | * @offset: of signal within controller's 0..(ngpio - 1) range | |
1367 | * | |
1368 | * Returns NULL if the GPIO is not currently requested, else a string. | |
1369 | * If debugfs support is enabled, the string returned is the label passed | |
1370 | * to gpio_request(); otherwise it is a meaningless constant. | |
1371 | * | |
1372 | * This function is for use by GPIO controller drivers. The label can | |
1373 | * help with diagnostics, and knowing that the signal is used as a GPIO | |
1374 | * can help avoid accidentally multiplexing it to another controller. | |
1375 | */ | |
1376 | const char *gpiochip_is_requested(struct gpio_chip *chip, unsigned offset) | |
1377 | { | |
1378 | unsigned gpio = chip->base + offset; | |
1379 | ||
e6de1808 | 1380 | if (!gpio_is_valid(gpio) || gpio_desc[gpio].chip != chip) |
d2876d08 DB |
1381 | return NULL; |
1382 | if (test_bit(FLAG_REQUESTED, &gpio_desc[gpio].flags) == 0) | |
1383 | return NULL; | |
1384 | #ifdef CONFIG_DEBUG_FS | |
1385 | return gpio_desc[gpio].label; | |
1386 | #else | |
1387 | return "?"; | |
1388 | #endif | |
1389 | } | |
1390 | EXPORT_SYMBOL_GPL(gpiochip_is_requested); | |
1391 | ||
1392 | ||
1393 | /* Drivers MUST set GPIO direction before making get/set calls. In | |
1394 | * some cases this is done in early boot, before IRQs are enabled. | |
1395 | * | |
1396 | * As a rule these aren't called more than once (except for drivers | |
1397 | * using the open-drain emulation idiom) so these are natural places | |
1398 | * to accumulate extra debugging checks. Note that we can't (yet) | |
1399 | * rely on gpio_request() having been called beforehand. | |
1400 | */ | |
1401 | ||
1402 | int gpio_direction_input(unsigned gpio) | |
1403 | { | |
1404 | unsigned long flags; | |
1405 | struct gpio_chip *chip; | |
1406 | struct gpio_desc *desc = &gpio_desc[gpio]; | |
1407 | int status = -EINVAL; | |
1408 | ||
1409 | spin_lock_irqsave(&gpio_lock, flags); | |
1410 | ||
e6de1808 | 1411 | if (!gpio_is_valid(gpio)) |
d2876d08 DB |
1412 | goto fail; |
1413 | chip = desc->chip; | |
1414 | if (!chip || !chip->get || !chip->direction_input) | |
1415 | goto fail; | |
1416 | gpio -= chip->base; | |
1417 | if (gpio >= chip->ngpio) | |
1418 | goto fail; | |
35e8bb51 DB |
1419 | status = gpio_ensure_requested(desc, gpio); |
1420 | if (status < 0) | |
1421 | goto fail; | |
d2876d08 DB |
1422 | |
1423 | /* now we know the gpio is valid and chip won't vanish */ | |
1424 | ||
1425 | spin_unlock_irqrestore(&gpio_lock, flags); | |
1426 | ||
9c4ba946 | 1427 | might_sleep_if(chip->can_sleep); |
d2876d08 | 1428 | |
35e8bb51 DB |
1429 | if (status) { |
1430 | status = chip->request(chip, gpio); | |
1431 | if (status < 0) { | |
1432 | pr_debug("GPIO-%d: chip request fail, %d\n", | |
1433 | chip->base + gpio, status); | |
1434 | /* and it's not available to anyone else ... | |
1435 | * gpio_request() is the fully clean solution. | |
1436 | */ | |
1437 | goto lose; | |
1438 | } | |
1439 | } | |
1440 | ||
d2876d08 DB |
1441 | status = chip->direction_input(chip, gpio); |
1442 | if (status == 0) | |
1443 | clear_bit(FLAG_IS_OUT, &desc->flags); | |
3f397c21 UKK |
1444 | |
1445 | trace_gpio_direction(chip->base + gpio, 1, status); | |
35e8bb51 | 1446 | lose: |
d2876d08 DB |
1447 | return status; |
1448 | fail: | |
1449 | spin_unlock_irqrestore(&gpio_lock, flags); | |
1450 | if (status) | |
1451 | pr_debug("%s: gpio-%d status %d\n", | |
145980a0 | 1452 | __func__, gpio, status); |
d2876d08 DB |
1453 | return status; |
1454 | } | |
1455 | EXPORT_SYMBOL_GPL(gpio_direction_input); | |
1456 | ||
1457 | int gpio_direction_output(unsigned gpio, int value) | |
1458 | { | |
1459 | unsigned long flags; | |
1460 | struct gpio_chip *chip; | |
1461 | struct gpio_desc *desc = &gpio_desc[gpio]; | |
1462 | int status = -EINVAL; | |
1463 | ||
aca5ce14 LD |
1464 | /* Open drain pin should not be driven to 1 */ |
1465 | if (value && test_bit(FLAG_OPEN_DRAIN, &desc->flags)) | |
1466 | return gpio_direction_input(gpio); | |
1467 | ||
25553ff0 LD |
1468 | /* Open source pin should not be driven to 0 */ |
1469 | if (!value && test_bit(FLAG_OPEN_SOURCE, &desc->flags)) | |
1470 | return gpio_direction_input(gpio); | |
1471 | ||
d2876d08 DB |
1472 | spin_lock_irqsave(&gpio_lock, flags); |
1473 | ||
e6de1808 | 1474 | if (!gpio_is_valid(gpio)) |
d2876d08 DB |
1475 | goto fail; |
1476 | chip = desc->chip; | |
1477 | if (!chip || !chip->set || !chip->direction_output) | |
1478 | goto fail; | |
1479 | gpio -= chip->base; | |
1480 | if (gpio >= chip->ngpio) | |
1481 | goto fail; | |
35e8bb51 DB |
1482 | status = gpio_ensure_requested(desc, gpio); |
1483 | if (status < 0) | |
1484 | goto fail; | |
d2876d08 DB |
1485 | |
1486 | /* now we know the gpio is valid and chip won't vanish */ | |
1487 | ||
1488 | spin_unlock_irqrestore(&gpio_lock, flags); | |
1489 | ||
9c4ba946 | 1490 | might_sleep_if(chip->can_sleep); |
d2876d08 | 1491 | |
35e8bb51 DB |
1492 | if (status) { |
1493 | status = chip->request(chip, gpio); | |
1494 | if (status < 0) { | |
1495 | pr_debug("GPIO-%d: chip request fail, %d\n", | |
1496 | chip->base + gpio, status); | |
1497 | /* and it's not available to anyone else ... | |
1498 | * gpio_request() is the fully clean solution. | |
1499 | */ | |
1500 | goto lose; | |
1501 | } | |
1502 | } | |
1503 | ||
d2876d08 DB |
1504 | status = chip->direction_output(chip, gpio, value); |
1505 | if (status == 0) | |
1506 | set_bit(FLAG_IS_OUT, &desc->flags); | |
3f397c21 UKK |
1507 | trace_gpio_value(chip->base + gpio, 0, value); |
1508 | trace_gpio_direction(chip->base + gpio, 0, status); | |
35e8bb51 | 1509 | lose: |
d2876d08 DB |
1510 | return status; |
1511 | fail: | |
1512 | spin_unlock_irqrestore(&gpio_lock, flags); | |
1513 | if (status) | |
1514 | pr_debug("%s: gpio-%d status %d\n", | |
145980a0 | 1515 | __func__, gpio, status); |
d2876d08 DB |
1516 | return status; |
1517 | } | |
1518 | EXPORT_SYMBOL_GPL(gpio_direction_output); | |
1519 | ||
c4b5be98 FB |
1520 | /** |
1521 | * gpio_set_debounce - sets @debounce time for a @gpio | |
1522 | * @gpio: the gpio to set debounce time | |
1523 | * @debounce: debounce time is microseconds | |
1524 | */ | |
1525 | int gpio_set_debounce(unsigned gpio, unsigned debounce) | |
1526 | { | |
1527 | unsigned long flags; | |
1528 | struct gpio_chip *chip; | |
1529 | struct gpio_desc *desc = &gpio_desc[gpio]; | |
1530 | int status = -EINVAL; | |
1531 | ||
1532 | spin_lock_irqsave(&gpio_lock, flags); | |
1533 | ||
1534 | if (!gpio_is_valid(gpio)) | |
1535 | goto fail; | |
1536 | chip = desc->chip; | |
1537 | if (!chip || !chip->set || !chip->set_debounce) | |
1538 | goto fail; | |
1539 | gpio -= chip->base; | |
1540 | if (gpio >= chip->ngpio) | |
1541 | goto fail; | |
1542 | status = gpio_ensure_requested(desc, gpio); | |
1543 | if (status < 0) | |
1544 | goto fail; | |
1545 | ||
1546 | /* now we know the gpio is valid and chip won't vanish */ | |
1547 | ||
1548 | spin_unlock_irqrestore(&gpio_lock, flags); | |
1549 | ||
9c4ba946 | 1550 | might_sleep_if(chip->can_sleep); |
c4b5be98 FB |
1551 | |
1552 | return chip->set_debounce(chip, gpio, debounce); | |
1553 | ||
1554 | fail: | |
1555 | spin_unlock_irqrestore(&gpio_lock, flags); | |
1556 | if (status) | |
1557 | pr_debug("%s: gpio-%d status %d\n", | |
1558 | __func__, gpio, status); | |
1559 | ||
1560 | return status; | |
1561 | } | |
1562 | EXPORT_SYMBOL_GPL(gpio_set_debounce); | |
d2876d08 DB |
1563 | |
1564 | /* I/O calls are only valid after configuration completed; the relevant | |
1565 | * "is this a valid GPIO" error checks should already have been done. | |
1566 | * | |
1567 | * "Get" operations are often inlinable as reading a pin value register, | |
1568 | * and masking the relevant bit in that register. | |
1569 | * | |
1570 | * When "set" operations are inlinable, they involve writing that mask to | |
1571 | * one register to set a low value, or a different register to set it high. | |
1572 | * Otherwise locking is needed, so there may be little value to inlining. | |
1573 | * | |
1574 | *------------------------------------------------------------------------ | |
1575 | * | |
1576 | * IMPORTANT!!! The hot paths -- get/set value -- assume that callers | |
1577 | * have requested the GPIO. That can include implicit requesting by | |
1578 | * a direction setting call. Marking a gpio as requested locks its chip | |
1579 | * in memory, guaranteeing that these table lookups need no more locking | |
1580 | * and that gpiochip_remove() will fail. | |
1581 | * | |
1582 | * REVISIT when debugging, consider adding some instrumentation to ensure | |
1583 | * that the GPIO was actually requested. | |
1584 | */ | |
1585 | ||
1586 | /** | |
1587 | * __gpio_get_value() - return a gpio's value | |
1588 | * @gpio: gpio whose value will be returned | |
1589 | * Context: any | |
1590 | * | |
1591 | * This is used directly or indirectly to implement gpio_get_value(). | |
1592 | * It returns the zero or nonzero value provided by the associated | |
1593 | * gpio_chip.get() method; or zero if no such method is provided. | |
1594 | */ | |
1595 | int __gpio_get_value(unsigned gpio) | |
1596 | { | |
1597 | struct gpio_chip *chip; | |
3f397c21 | 1598 | int value; |
d2876d08 DB |
1599 | |
1600 | chip = gpio_to_chip(gpio); | |
e4e449e8 | 1601 | /* Should be using gpio_get_value_cansleep() */ |
9c4ba946 | 1602 | WARN_ON(chip->can_sleep); |
3f397c21 UKK |
1603 | value = chip->get ? chip->get(chip, gpio - chip->base) : 0; |
1604 | trace_gpio_value(gpio, 1, value); | |
1605 | return value; | |
d2876d08 DB |
1606 | } |
1607 | EXPORT_SYMBOL_GPL(__gpio_get_value); | |
1608 | ||
aca5ce14 LD |
1609 | /* |
1610 | * _gpio_set_open_drain_value() - Set the open drain gpio's value. | |
1611 | * @gpio: Gpio whose state need to be set. | |
1612 | * @chip: Gpio chip. | |
1613 | * @value: Non-zero for setting it HIGH otherise it will set to LOW. | |
1614 | */ | |
1615 | static void _gpio_set_open_drain_value(unsigned gpio, | |
1616 | struct gpio_chip *chip, int value) | |
1617 | { | |
1618 | int err = 0; | |
1619 | if (value) { | |
1620 | err = chip->direction_input(chip, gpio - chip->base); | |
1621 | if (!err) | |
1622 | clear_bit(FLAG_IS_OUT, &gpio_desc[gpio].flags); | |
1623 | } else { | |
1624 | err = chip->direction_output(chip, gpio - chip->base, 0); | |
1625 | if (!err) | |
1626 | set_bit(FLAG_IS_OUT, &gpio_desc[gpio].flags); | |
1627 | } | |
1628 | trace_gpio_direction(gpio, value, err); | |
1629 | if (err < 0) | |
1630 | pr_err("%s: Error in set_value for open drain gpio%d err %d\n", | |
1631 | __func__, gpio, err); | |
1632 | } | |
1633 | ||
25553ff0 LD |
1634 | /* |
1635 | * _gpio_set_open_source() - Set the open source gpio's value. | |
1636 | * @gpio: Gpio whose state need to be set. | |
1637 | * @chip: Gpio chip. | |
1638 | * @value: Non-zero for setting it HIGH otherise it will set to LOW. | |
1639 | */ | |
1640 | static void _gpio_set_open_source_value(unsigned gpio, | |
1641 | struct gpio_chip *chip, int value) | |
1642 | { | |
1643 | int err = 0; | |
1644 | if (value) { | |
1645 | err = chip->direction_output(chip, gpio - chip->base, 1); | |
1646 | if (!err) | |
1647 | set_bit(FLAG_IS_OUT, &gpio_desc[gpio].flags); | |
1648 | } else { | |
1649 | err = chip->direction_input(chip, gpio - chip->base); | |
1650 | if (!err) | |
1651 | clear_bit(FLAG_IS_OUT, &gpio_desc[gpio].flags); | |
1652 | } | |
1653 | trace_gpio_direction(gpio, !value, err); | |
1654 | if (err < 0) | |
1655 | pr_err("%s: Error in set_value for open source gpio%d err %d\n", | |
1656 | __func__, gpio, err); | |
1657 | } | |
1658 | ||
1659 | ||
d2876d08 DB |
1660 | /** |
1661 | * __gpio_set_value() - assign a gpio's value | |
1662 | * @gpio: gpio whose value will be assigned | |
1663 | * @value: value to assign | |
1664 | * Context: any | |
1665 | * | |
1666 | * This is used directly or indirectly to implement gpio_set_value(). | |
1667 | * It invokes the associated gpio_chip.set() method. | |
1668 | */ | |
1669 | void __gpio_set_value(unsigned gpio, int value) | |
1670 | { | |
1671 | struct gpio_chip *chip; | |
1672 | ||
1673 | chip = gpio_to_chip(gpio); | |
e4e449e8 | 1674 | /* Should be using gpio_set_value_cansleep() */ |
9c4ba946 | 1675 | WARN_ON(chip->can_sleep); |
3f397c21 | 1676 | trace_gpio_value(gpio, 0, value); |
aca5ce14 LD |
1677 | if (test_bit(FLAG_OPEN_DRAIN, &gpio_desc[gpio].flags)) |
1678 | _gpio_set_open_drain_value(gpio, chip, value); | |
25553ff0 LD |
1679 | else if (test_bit(FLAG_OPEN_SOURCE, &gpio_desc[gpio].flags)) |
1680 | _gpio_set_open_source_value(gpio, chip, value); | |
aca5ce14 LD |
1681 | else |
1682 | chip->set(chip, gpio - chip->base, value); | |
d2876d08 DB |
1683 | } |
1684 | EXPORT_SYMBOL_GPL(__gpio_set_value); | |
1685 | ||
1686 | /** | |
1687 | * __gpio_cansleep() - report whether gpio value access will sleep | |
1688 | * @gpio: gpio in question | |
1689 | * Context: any | |
1690 | * | |
1691 | * This is used directly or indirectly to implement gpio_cansleep(). It | |
1692 | * returns nonzero if access reading or writing the GPIO value can sleep. | |
1693 | */ | |
1694 | int __gpio_cansleep(unsigned gpio) | |
1695 | { | |
1696 | struct gpio_chip *chip; | |
1697 | ||
1698 | /* only call this on GPIOs that are valid! */ | |
1699 | chip = gpio_to_chip(gpio); | |
1700 | ||
1701 | return chip->can_sleep; | |
1702 | } | |
1703 | EXPORT_SYMBOL_GPL(__gpio_cansleep); | |
1704 | ||
0f6d504e DB |
1705 | /** |
1706 | * __gpio_to_irq() - return the IRQ corresponding to a GPIO | |
1707 | * @gpio: gpio whose IRQ will be returned (already requested) | |
1708 | * Context: any | |
1709 | * | |
1710 | * This is used directly or indirectly to implement gpio_to_irq(). | |
1711 | * It returns the number of the IRQ signaled by this (input) GPIO, | |
1712 | * or a negative errno. | |
1713 | */ | |
1714 | int __gpio_to_irq(unsigned gpio) | |
1715 | { | |
1716 | struct gpio_chip *chip; | |
1717 | ||
1718 | chip = gpio_to_chip(gpio); | |
1719 | return chip->to_irq ? chip->to_irq(chip, gpio - chip->base) : -ENXIO; | |
1720 | } | |
1721 | EXPORT_SYMBOL_GPL(__gpio_to_irq); | |
1722 | ||
d2876d08 DB |
1723 | |
1724 | ||
1725 | /* There's no value in making it easy to inline GPIO calls that may sleep. | |
1726 | * Common examples include ones connected to I2C or SPI chips. | |
1727 | */ | |
1728 | ||
1729 | int gpio_get_value_cansleep(unsigned gpio) | |
1730 | { | |
1731 | struct gpio_chip *chip; | |
3f397c21 | 1732 | int value; |
d2876d08 DB |
1733 | |
1734 | might_sleep_if(extra_checks); | |
1735 | chip = gpio_to_chip(gpio); | |
3f397c21 UKK |
1736 | value = chip->get ? chip->get(chip, gpio - chip->base) : 0; |
1737 | trace_gpio_value(gpio, 1, value); | |
1738 | return value; | |
d2876d08 DB |
1739 | } |
1740 | EXPORT_SYMBOL_GPL(gpio_get_value_cansleep); | |
1741 | ||
1742 | void gpio_set_value_cansleep(unsigned gpio, int value) | |
1743 | { | |
1744 | struct gpio_chip *chip; | |
1745 | ||
1746 | might_sleep_if(extra_checks); | |
1747 | chip = gpio_to_chip(gpio); | |
3f397c21 | 1748 | trace_gpio_value(gpio, 0, value); |
aca5ce14 LD |
1749 | if (test_bit(FLAG_OPEN_DRAIN, &gpio_desc[gpio].flags)) |
1750 | _gpio_set_open_drain_value(gpio, chip, value); | |
25553ff0 LD |
1751 | else if (test_bit(FLAG_OPEN_SOURCE, &gpio_desc[gpio].flags)) |
1752 | _gpio_set_open_source_value(gpio, chip, value); | |
aca5ce14 LD |
1753 | else |
1754 | chip->set(chip, gpio - chip->base, value); | |
d2876d08 DB |
1755 | } |
1756 | EXPORT_SYMBOL_GPL(gpio_set_value_cansleep); | |
1757 | ||
1758 | ||
1759 | #ifdef CONFIG_DEBUG_FS | |
1760 | ||
d2876d08 DB |
1761 | static void gpiolib_dbg_show(struct seq_file *s, struct gpio_chip *chip) |
1762 | { | |
1763 | unsigned i; | |
1764 | unsigned gpio = chip->base; | |
1765 | struct gpio_desc *gdesc = &gpio_desc[gpio]; | |
1766 | int is_out; | |
1767 | ||
1768 | for (i = 0; i < chip->ngpio; i++, gpio++, gdesc++) { | |
1769 | if (!test_bit(FLAG_REQUESTED, &gdesc->flags)) | |
1770 | continue; | |
1771 | ||
1772 | is_out = test_bit(FLAG_IS_OUT, &gdesc->flags); | |
6e8ba729 | 1773 | seq_printf(s, " gpio-%-3d (%-20.20s) %s %s", |
d2876d08 DB |
1774 | gpio, gdesc->label, |
1775 | is_out ? "out" : "in ", | |
1776 | chip->get | |
1777 | ? (chip->get(chip, i) ? "hi" : "lo") | |
1778 | : "? "); | |
d2876d08 DB |
1779 | seq_printf(s, "\n"); |
1780 | } | |
1781 | } | |
1782 | ||
f9c4a31f | 1783 | static void *gpiolib_seq_start(struct seq_file *s, loff_t *pos) |
d2876d08 | 1784 | { |
f9c4a31f TR |
1785 | struct gpio_chip *chip = NULL; |
1786 | unsigned int gpio; | |
1787 | void *ret = NULL; | |
1788 | loff_t index = 0; | |
d2876d08 DB |
1789 | |
1790 | /* REVISIT this isn't locked against gpio_chip removal ... */ | |
1791 | ||
e6de1808 | 1792 | for (gpio = 0; gpio_is_valid(gpio); gpio++) { |
f9c4a31f | 1793 | if (gpio_desc[gpio].chip == chip) |
d2876d08 | 1794 | continue; |
f9c4a31f | 1795 | |
d2876d08 DB |
1796 | chip = gpio_desc[gpio].chip; |
1797 | if (!chip) | |
1798 | continue; | |
1799 | ||
f9c4a31f TR |
1800 | if (index++ >= *pos) { |
1801 | ret = chip; | |
1802 | break; | |
1803 | } | |
d2876d08 | 1804 | } |
f9c4a31f TR |
1805 | |
1806 | s->private = ""; | |
1807 | ||
1808 | return ret; | |
1809 | } | |
1810 | ||
1811 | static void *gpiolib_seq_next(struct seq_file *s, void *v, loff_t *pos) | |
1812 | { | |
1813 | struct gpio_chip *chip = v; | |
1814 | unsigned int gpio; | |
1815 | void *ret = NULL; | |
1816 | ||
1817 | /* skip GPIOs provided by the current chip */ | |
1818 | for (gpio = chip->base + chip->ngpio; gpio_is_valid(gpio); gpio++) { | |
1819 | chip = gpio_desc[gpio].chip; | |
1820 | if (chip) { | |
1821 | ret = chip; | |
1822 | break; | |
1823 | } | |
1824 | } | |
1825 | ||
1826 | s->private = "\n"; | |
1827 | ++*pos; | |
1828 | ||
1829 | return ret; | |
1830 | } | |
1831 | ||
1832 | static void gpiolib_seq_stop(struct seq_file *s, void *v) | |
1833 | { | |
1834 | } | |
1835 | ||
1836 | static int gpiolib_seq_show(struct seq_file *s, void *v) | |
1837 | { | |
1838 | struct gpio_chip *chip = v; | |
1839 | struct device *dev; | |
1840 | ||
1841 | seq_printf(s, "%sGPIOs %d-%d", (char *)s->private, | |
1842 | chip->base, chip->base + chip->ngpio - 1); | |
1843 | dev = chip->dev; | |
1844 | if (dev) | |
1845 | seq_printf(s, ", %s/%s", dev->bus ? dev->bus->name : "no-bus", | |
1846 | dev_name(dev)); | |
1847 | if (chip->label) | |
1848 | seq_printf(s, ", %s", chip->label); | |
1849 | if (chip->can_sleep) | |
1850 | seq_printf(s, ", can sleep"); | |
1851 | seq_printf(s, ":\n"); | |
1852 | ||
1853 | if (chip->dbg_show) | |
1854 | chip->dbg_show(s, chip); | |
1855 | else | |
1856 | gpiolib_dbg_show(s, chip); | |
1857 | ||
d2876d08 DB |
1858 | return 0; |
1859 | } | |
1860 | ||
f9c4a31f TR |
1861 | static const struct seq_operations gpiolib_seq_ops = { |
1862 | .start = gpiolib_seq_start, | |
1863 | .next = gpiolib_seq_next, | |
1864 | .stop = gpiolib_seq_stop, | |
1865 | .show = gpiolib_seq_show, | |
1866 | }; | |
1867 | ||
d2876d08 DB |
1868 | static int gpiolib_open(struct inode *inode, struct file *file) |
1869 | { | |
f9c4a31f | 1870 | return seq_open(file, &gpiolib_seq_ops); |
d2876d08 DB |
1871 | } |
1872 | ||
828c0950 | 1873 | static const struct file_operations gpiolib_operations = { |
f9c4a31f | 1874 | .owner = THIS_MODULE, |
d2876d08 DB |
1875 | .open = gpiolib_open, |
1876 | .read = seq_read, | |
1877 | .llseek = seq_lseek, | |
f9c4a31f | 1878 | .release = seq_release, |
d2876d08 DB |
1879 | }; |
1880 | ||
1881 | static int __init gpiolib_debugfs_init(void) | |
1882 | { | |
1883 | /* /sys/kernel/debug/gpio */ | |
1884 | (void) debugfs_create_file("gpio", S_IFREG | S_IRUGO, | |
1885 | NULL, NULL, &gpiolib_operations); | |
1886 | return 0; | |
1887 | } | |
1888 | subsys_initcall(gpiolib_debugfs_init); | |
1889 | ||
1890 | #endif /* DEBUG_FS */ |