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0eb4c6c2 AC |
1 | #include <linux/idr.h> |
2 | #include <linux/mutex.h> | |
3 | #include <linux/device.h> | |
4 | #include <linux/sysfs.h> | |
5 | #include <linux/gpio/consumer.h> | |
6 | #include <linux/gpio/driver.h> | |
7 | #include <linux/interrupt.h> | |
8 | #include <linux/kdev_t.h> | |
c43960fb | 9 | #include <linux/slab.h> |
0eb4c6c2 AC |
10 | |
11 | #include "gpiolib.h" | |
12 | ||
c43960fb JH |
13 | struct gpiod_data { |
14 | struct gpio_desc *desc; | |
a08f5c21 | 15 | struct kernfs_node *value_kn; |
2ec74a95 | 16 | int irq; |
c43960fb JH |
17 | }; |
18 | ||
0eb4c6c2 AC |
19 | /* lock protects against unexport_gpio() being called while |
20 | * sysfs files are active. | |
21 | */ | |
22 | static DEFINE_MUTEX(sysfs_lock); | |
23 | ||
24 | /* | |
25 | * /sys/class/gpio/gpioN... only for GPIOs that are exported | |
26 | * /direction | |
27 | * * MAY BE OMITTED if kernel won't allow direction changes | |
28 | * * is read/write as "in" or "out" | |
29 | * * may also be written as "high" or "low", initializing | |
30 | * output value as specified ("out" implies "low") | |
31 | * /value | |
32 | * * always readable, subject to hardware behavior | |
33 | * * may be writable, as zero/nonzero | |
34 | * /edge | |
35 | * * configures behavior of poll(2) on /value | |
36 | * * available only if pin can generate IRQs on input | |
37 | * * is read/write as "none", "falling", "rising", or "both" | |
38 | * /active_low | |
39 | * * configures polarity of /value | |
40 | * * is read/write as zero/nonzero | |
41 | * * also affects existing and subsequent "falling" and "rising" | |
42 | * /edge configuration | |
43 | */ | |
44 | ||
6beac9d1 | 45 | static ssize_t direction_show(struct device *dev, |
0eb4c6c2 AC |
46 | struct device_attribute *attr, char *buf) |
47 | { | |
c43960fb JH |
48 | struct gpiod_data *data = dev_get_drvdata(dev); |
49 | struct gpio_desc *desc = data->desc; | |
0eb4c6c2 AC |
50 | ssize_t status; |
51 | ||
52 | mutex_lock(&sysfs_lock); | |
53 | ||
f0b7866a JH |
54 | gpiod_get_direction(desc); |
55 | status = sprintf(buf, "%s\n", | |
0eb4c6c2 AC |
56 | test_bit(FLAG_IS_OUT, &desc->flags) |
57 | ? "out" : "in"); | |
0eb4c6c2 AC |
58 | |
59 | mutex_unlock(&sysfs_lock); | |
60 | return status; | |
61 | } | |
62 | ||
6beac9d1 | 63 | static ssize_t direction_store(struct device *dev, |
0eb4c6c2 AC |
64 | struct device_attribute *attr, const char *buf, size_t size) |
65 | { | |
c43960fb JH |
66 | struct gpiod_data *data = dev_get_drvdata(dev); |
67 | struct gpio_desc *desc = data->desc; | |
0eb4c6c2 AC |
68 | ssize_t status; |
69 | ||
70 | mutex_lock(&sysfs_lock); | |
71 | ||
f0b7866a | 72 | if (sysfs_streq(buf, "high")) |
0eb4c6c2 AC |
73 | status = gpiod_direction_output_raw(desc, 1); |
74 | else if (sysfs_streq(buf, "out") || sysfs_streq(buf, "low")) | |
75 | status = gpiod_direction_output_raw(desc, 0); | |
76 | else if (sysfs_streq(buf, "in")) | |
77 | status = gpiod_direction_input(desc); | |
78 | else | |
79 | status = -EINVAL; | |
80 | ||
81 | mutex_unlock(&sysfs_lock); | |
82 | return status ? : size; | |
83 | } | |
6beac9d1 | 84 | static DEVICE_ATTR_RW(direction); |
0eb4c6c2 | 85 | |
6beac9d1 | 86 | static ssize_t value_show(struct device *dev, |
0eb4c6c2 AC |
87 | struct device_attribute *attr, char *buf) |
88 | { | |
c43960fb JH |
89 | struct gpiod_data *data = dev_get_drvdata(dev); |
90 | struct gpio_desc *desc = data->desc; | |
0eb4c6c2 AC |
91 | ssize_t status; |
92 | ||
93 | mutex_lock(&sysfs_lock); | |
94 | ||
f0b7866a | 95 | status = sprintf(buf, "%d\n", gpiod_get_value_cansleep(desc)); |
0eb4c6c2 AC |
96 | |
97 | mutex_unlock(&sysfs_lock); | |
98 | return status; | |
99 | } | |
100 | ||
6beac9d1 | 101 | static ssize_t value_store(struct device *dev, |
0eb4c6c2 AC |
102 | struct device_attribute *attr, const char *buf, size_t size) |
103 | { | |
c43960fb JH |
104 | struct gpiod_data *data = dev_get_drvdata(dev); |
105 | struct gpio_desc *desc = data->desc; | |
0eb4c6c2 AC |
106 | ssize_t status; |
107 | ||
108 | mutex_lock(&sysfs_lock); | |
109 | ||
f0b7866a | 110 | if (!test_bit(FLAG_IS_OUT, &desc->flags)) { |
0eb4c6c2 | 111 | status = -EPERM; |
f0b7866a | 112 | } else { |
0eb4c6c2 AC |
113 | long value; |
114 | ||
115 | status = kstrtol(buf, 0, &value); | |
116 | if (status == 0) { | |
117 | gpiod_set_value_cansleep(desc, value); | |
118 | status = size; | |
119 | } | |
120 | } | |
121 | ||
122 | mutex_unlock(&sysfs_lock); | |
123 | return status; | |
124 | } | |
6beac9d1 | 125 | static DEVICE_ATTR_RW(value); |
0eb4c6c2 AC |
126 | |
127 | static irqreturn_t gpio_sysfs_irq(int irq, void *priv) | |
128 | { | |
a08f5c21 JH |
129 | struct gpiod_data *data = priv; |
130 | ||
131 | sysfs_notify_dirent(data->value_kn); | |
0eb4c6c2 | 132 | |
0eb4c6c2 AC |
133 | return IRQ_HANDLED; |
134 | } | |
135 | ||
2ec74a95 | 136 | static int gpio_sysfs_request_irq(struct device *dev, unsigned long gpio_flags) |
0eb4c6c2 | 137 | { |
0f628508 JH |
138 | struct gpiod_data *data = dev_get_drvdata(dev); |
139 | struct gpio_desc *desc = data->desc; | |
0eb4c6c2 | 140 | unsigned long irq_flags; |
2ec74a95 | 141 | int ret; |
0eb4c6c2 | 142 | |
2ec74a95 JH |
143 | data->irq = gpiod_to_irq(desc); |
144 | if (data->irq < 0) | |
0eb4c6c2 AC |
145 | return -EIO; |
146 | ||
2ec74a95 JH |
147 | data->value_kn = sysfs_get_dirent(dev->kobj.sd, "value"); |
148 | if (!data->value_kn) | |
149 | return -ENODEV; | |
0eb4c6c2 AC |
150 | |
151 | irq_flags = IRQF_SHARED; | |
152 | if (test_bit(FLAG_TRIG_FALL, &gpio_flags)) | |
153 | irq_flags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ? | |
154 | IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING; | |
155 | if (test_bit(FLAG_TRIG_RISE, &gpio_flags)) | |
156 | irq_flags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ? | |
157 | IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING; | |
158 | ||
52176d0d JH |
159 | /* |
160 | * FIXME: This should be done in the irq_request_resources callback | |
161 | * when the irq is requested, but a few drivers currently fail | |
162 | * to do so. | |
163 | * | |
164 | * Remove this redundant call (along with the corresponding | |
165 | * unlock) when those drivers have been fixed. | |
166 | */ | |
167 | ret = gpiochip_lock_as_irq(desc->chip, gpio_chip_hwgpio(desc)); | |
0eb4c6c2 | 168 | if (ret < 0) |
2ec74a95 | 169 | goto err_put_kn; |
0eb4c6c2 | 170 | |
2ec74a95 | 171 | ret = request_any_context_irq(data->irq, gpio_sysfs_irq, irq_flags, |
a08f5c21 | 172 | "gpiolib", data); |
52176d0d JH |
173 | if (ret < 0) |
174 | goto err_unlock; | |
0eb4c6c2 AC |
175 | |
176 | desc->flags |= gpio_flags; | |
2ec74a95 | 177 | |
0eb4c6c2 AC |
178 | return 0; |
179 | ||
52176d0d JH |
180 | err_unlock: |
181 | gpiochip_unlock_as_irq(desc->chip, gpio_chip_hwgpio(desc)); | |
2ec74a95 JH |
182 | err_put_kn: |
183 | sysfs_put(data->value_kn); | |
184 | ||
0eb4c6c2 AC |
185 | return ret; |
186 | } | |
187 | ||
2ec74a95 JH |
188 | static void gpio_sysfs_free_irq(struct device *dev) |
189 | { | |
190 | struct gpiod_data *data = dev_get_drvdata(dev); | |
191 | struct gpio_desc *desc = data->desc; | |
192 | ||
193 | desc->flags &= ~GPIO_TRIGGER_MASK; | |
194 | free_irq(data->irq, data); | |
195 | gpiochip_unlock_as_irq(desc->chip, gpio_chip_hwgpio(desc)); | |
196 | sysfs_put(data->value_kn); | |
197 | } | |
198 | ||
0eb4c6c2 AC |
199 | static const struct { |
200 | const char *name; | |
201 | unsigned long flags; | |
202 | } trigger_types[] = { | |
203 | { "none", 0 }, | |
204 | { "falling", BIT(FLAG_TRIG_FALL) }, | |
205 | { "rising", BIT(FLAG_TRIG_RISE) }, | |
206 | { "both", BIT(FLAG_TRIG_FALL) | BIT(FLAG_TRIG_RISE) }, | |
207 | }; | |
208 | ||
6beac9d1 | 209 | static ssize_t edge_show(struct device *dev, |
0eb4c6c2 AC |
210 | struct device_attribute *attr, char *buf) |
211 | { | |
c43960fb JH |
212 | struct gpiod_data *data = dev_get_drvdata(dev); |
213 | struct gpio_desc *desc = data->desc; | |
f0b7866a JH |
214 | unsigned long mask; |
215 | ssize_t status = 0; | |
216 | int i; | |
0eb4c6c2 AC |
217 | |
218 | mutex_lock(&sysfs_lock); | |
219 | ||
f0b7866a JH |
220 | for (i = 0; i < ARRAY_SIZE(trigger_types); i++) { |
221 | mask = desc->flags & GPIO_TRIGGER_MASK; | |
222 | if (mask == trigger_types[i].flags) { | |
223 | status = sprintf(buf, "%s\n", trigger_types[i].name); | |
224 | break; | |
225 | } | |
0eb4c6c2 AC |
226 | } |
227 | ||
228 | mutex_unlock(&sysfs_lock); | |
229 | return status; | |
230 | } | |
231 | ||
6beac9d1 | 232 | static ssize_t edge_store(struct device *dev, |
0eb4c6c2 AC |
233 | struct device_attribute *attr, const char *buf, size_t size) |
234 | { | |
b91e1807 JH |
235 | struct gpiod_data *data = dev_get_drvdata(dev); |
236 | struct gpio_desc *desc = data->desc; | |
237 | unsigned long flags; | |
2ec74a95 | 238 | ssize_t status = size; |
e4339ce3 | 239 | int i; |
0eb4c6c2 | 240 | |
e4339ce3 | 241 | for (i = 0; i < ARRAY_SIZE(trigger_types); i++) { |
0eb4c6c2 | 242 | if (sysfs_streq(trigger_types[i].name, buf)) |
e4339ce3 JH |
243 | break; |
244 | } | |
245 | ||
246 | if (i == ARRAY_SIZE(trigger_types)) | |
247 | return -EINVAL; | |
0eb4c6c2 | 248 | |
b91e1807 JH |
249 | flags = trigger_types[i].flags; |
250 | ||
0eb4c6c2 AC |
251 | mutex_lock(&sysfs_lock); |
252 | ||
b91e1807 JH |
253 | if ((desc->flags & GPIO_TRIGGER_MASK) == flags) { |
254 | status = size; | |
255 | goto out_unlock; | |
256 | } | |
257 | ||
2ec74a95 JH |
258 | if (desc->flags & GPIO_TRIGGER_MASK) |
259 | gpio_sysfs_free_irq(dev); | |
260 | ||
261 | if (flags) { | |
262 | status = gpio_sysfs_request_irq(dev, flags); | |
263 | if (!status) | |
264 | status = size; | |
265 | } | |
0eb4c6c2 | 266 | |
b91e1807 | 267 | out_unlock: |
0eb4c6c2 AC |
268 | mutex_unlock(&sysfs_lock); |
269 | ||
270 | return status; | |
271 | } | |
6beac9d1 | 272 | static DEVICE_ATTR_RW(edge); |
0eb4c6c2 | 273 | |
0f628508 | 274 | static int sysfs_set_active_low(struct device *dev, int value) |
0eb4c6c2 | 275 | { |
0f628508 JH |
276 | struct gpiod_data *data = dev_get_drvdata(dev); |
277 | struct gpio_desc *desc = data->desc; | |
0eb4c6c2 AC |
278 | int status = 0; |
279 | ||
280 | if (!!test_bit(FLAG_ACTIVE_LOW, &desc->flags) == !!value) | |
281 | return 0; | |
282 | ||
283 | if (value) | |
284 | set_bit(FLAG_ACTIVE_LOW, &desc->flags); | |
285 | else | |
286 | clear_bit(FLAG_ACTIVE_LOW, &desc->flags); | |
287 | ||
288 | /* reconfigure poll(2) support if enabled on one edge only */ | |
166a85e4 JH |
289 | if (!!test_bit(FLAG_TRIG_RISE, &desc->flags) ^ |
290 | !!test_bit(FLAG_TRIG_FALL, &desc->flags)) { | |
0eb4c6c2 AC |
291 | unsigned long trigger_flags = desc->flags & GPIO_TRIGGER_MASK; |
292 | ||
2ec74a95 JH |
293 | gpio_sysfs_free_irq(dev); |
294 | status = gpio_sysfs_request_irq(dev, trigger_flags); | |
0eb4c6c2 AC |
295 | } |
296 | ||
297 | return status; | |
298 | } | |
299 | ||
6beac9d1 | 300 | static ssize_t active_low_show(struct device *dev, |
0eb4c6c2 AC |
301 | struct device_attribute *attr, char *buf) |
302 | { | |
c43960fb JH |
303 | struct gpiod_data *data = dev_get_drvdata(dev); |
304 | struct gpio_desc *desc = data->desc; | |
0eb4c6c2 AC |
305 | ssize_t status; |
306 | ||
307 | mutex_lock(&sysfs_lock); | |
308 | ||
f0b7866a | 309 | status = sprintf(buf, "%d\n", |
0eb4c6c2 AC |
310 | !!test_bit(FLAG_ACTIVE_LOW, &desc->flags)); |
311 | ||
312 | mutex_unlock(&sysfs_lock); | |
313 | ||
314 | return status; | |
315 | } | |
316 | ||
6beac9d1 | 317 | static ssize_t active_low_store(struct device *dev, |
0eb4c6c2 AC |
318 | struct device_attribute *attr, const char *buf, size_t size) |
319 | { | |
0eb4c6c2 | 320 | ssize_t status; |
f0b7866a | 321 | long value; |
0eb4c6c2 AC |
322 | |
323 | mutex_lock(&sysfs_lock); | |
324 | ||
f0b7866a JH |
325 | status = kstrtol(buf, 0, &value); |
326 | if (status == 0) | |
0f628508 | 327 | status = sysfs_set_active_low(dev, value != 0); |
0eb4c6c2 AC |
328 | |
329 | mutex_unlock(&sysfs_lock); | |
330 | ||
331 | return status ? : size; | |
332 | } | |
6beac9d1 | 333 | static DEVICE_ATTR_RW(active_low); |
0eb4c6c2 | 334 | |
ebbeba12 JH |
335 | static umode_t gpio_is_visible(struct kobject *kobj, struct attribute *attr, |
336 | int n) | |
337 | { | |
338 | struct device *dev = container_of(kobj, struct device, kobj); | |
c43960fb JH |
339 | struct gpiod_data *data = dev_get_drvdata(dev); |
340 | struct gpio_desc *desc = data->desc; | |
ebbeba12 JH |
341 | umode_t mode = attr->mode; |
342 | bool show_direction = test_bit(FLAG_SYSFS_DIR, &desc->flags); | |
343 | ||
344 | if (attr == &dev_attr_direction.attr) { | |
345 | if (!show_direction) | |
346 | mode = 0; | |
347 | } else if (attr == &dev_attr_edge.attr) { | |
348 | if (gpiod_to_irq(desc) < 0) | |
349 | mode = 0; | |
350 | if (!show_direction && test_bit(FLAG_IS_OUT, &desc->flags)) | |
351 | mode = 0; | |
352 | } | |
353 | ||
354 | return mode; | |
355 | } | |
356 | ||
0915e6fe | 357 | static struct attribute *gpio_attrs[] = { |
ebbeba12 JH |
358 | &dev_attr_direction.attr, |
359 | &dev_attr_edge.attr, | |
0eb4c6c2 AC |
360 | &dev_attr_value.attr, |
361 | &dev_attr_active_low.attr, | |
362 | NULL, | |
363 | }; | |
ebbeba12 JH |
364 | |
365 | static const struct attribute_group gpio_group = { | |
366 | .attrs = gpio_attrs, | |
367 | .is_visible = gpio_is_visible, | |
368 | }; | |
369 | ||
370 | static const struct attribute_group *gpio_groups[] = { | |
371 | &gpio_group, | |
372 | NULL | |
373 | }; | |
0eb4c6c2 AC |
374 | |
375 | /* | |
376 | * /sys/class/gpio/gpiochipN/ | |
377 | * /base ... matching gpio_chip.base (N) | |
378 | * /label ... matching gpio_chip.label | |
379 | * /ngpio ... matching gpio_chip.ngpio | |
380 | */ | |
381 | ||
6beac9d1 | 382 | static ssize_t base_show(struct device *dev, |
0eb4c6c2 AC |
383 | struct device_attribute *attr, char *buf) |
384 | { | |
385 | const struct gpio_chip *chip = dev_get_drvdata(dev); | |
386 | ||
387 | return sprintf(buf, "%d\n", chip->base); | |
388 | } | |
6beac9d1 | 389 | static DEVICE_ATTR_RO(base); |
0eb4c6c2 | 390 | |
6beac9d1 | 391 | static ssize_t label_show(struct device *dev, |
0eb4c6c2 AC |
392 | struct device_attribute *attr, char *buf) |
393 | { | |
394 | const struct gpio_chip *chip = dev_get_drvdata(dev); | |
395 | ||
396 | return sprintf(buf, "%s\n", chip->label ? : ""); | |
397 | } | |
6beac9d1 | 398 | static DEVICE_ATTR_RO(label); |
0eb4c6c2 | 399 | |
6beac9d1 | 400 | static ssize_t ngpio_show(struct device *dev, |
0eb4c6c2 AC |
401 | struct device_attribute *attr, char *buf) |
402 | { | |
403 | const struct gpio_chip *chip = dev_get_drvdata(dev); | |
404 | ||
405 | return sprintf(buf, "%u\n", chip->ngpio); | |
406 | } | |
6beac9d1 | 407 | static DEVICE_ATTR_RO(ngpio); |
0eb4c6c2 | 408 | |
121b6a79 | 409 | static struct attribute *gpiochip_attrs[] = { |
0eb4c6c2 AC |
410 | &dev_attr_base.attr, |
411 | &dev_attr_label.attr, | |
412 | &dev_attr_ngpio.attr, | |
413 | NULL, | |
414 | }; | |
121b6a79 | 415 | ATTRIBUTE_GROUPS(gpiochip); |
0eb4c6c2 AC |
416 | |
417 | /* | |
418 | * /sys/class/gpio/export ... write-only | |
419 | * integer N ... number of GPIO to export (full access) | |
420 | * /sys/class/gpio/unexport ... write-only | |
421 | * integer N ... number of GPIO to unexport | |
422 | */ | |
423 | static ssize_t export_store(struct class *class, | |
424 | struct class_attribute *attr, | |
425 | const char *buf, size_t len) | |
426 | { | |
427 | long gpio; | |
428 | struct gpio_desc *desc; | |
429 | int status; | |
430 | ||
431 | status = kstrtol(buf, 0, &gpio); | |
432 | if (status < 0) | |
433 | goto done; | |
434 | ||
435 | desc = gpio_to_desc(gpio); | |
436 | /* reject invalid GPIOs */ | |
437 | if (!desc) { | |
438 | pr_warn("%s: invalid GPIO %ld\n", __func__, gpio); | |
439 | return -EINVAL; | |
440 | } | |
441 | ||
442 | /* No extra locking here; FLAG_SYSFS just signifies that the | |
443 | * request and export were done by on behalf of userspace, so | |
444 | * they may be undone on its behalf too. | |
445 | */ | |
446 | ||
447 | status = gpiod_request(desc, "sysfs"); | |
448 | if (status < 0) { | |
449 | if (status == -EPROBE_DEFER) | |
450 | status = -ENODEV; | |
451 | goto done; | |
452 | } | |
453 | status = gpiod_export(desc, true); | |
454 | if (status < 0) | |
455 | gpiod_free(desc); | |
456 | else | |
457 | set_bit(FLAG_SYSFS, &desc->flags); | |
458 | ||
459 | done: | |
460 | if (status) | |
461 | pr_debug("%s: status %d\n", __func__, status); | |
462 | return status ? : len; | |
463 | } | |
464 | ||
465 | static ssize_t unexport_store(struct class *class, | |
466 | struct class_attribute *attr, | |
467 | const char *buf, size_t len) | |
468 | { | |
469 | long gpio; | |
470 | struct gpio_desc *desc; | |
471 | int status; | |
472 | ||
473 | status = kstrtol(buf, 0, &gpio); | |
474 | if (status < 0) | |
475 | goto done; | |
476 | ||
477 | desc = gpio_to_desc(gpio); | |
478 | /* reject bogus commands (gpio_unexport ignores them) */ | |
479 | if (!desc) { | |
480 | pr_warn("%s: invalid GPIO %ld\n", __func__, gpio); | |
481 | return -EINVAL; | |
482 | } | |
483 | ||
484 | status = -EINVAL; | |
485 | ||
486 | /* No extra locking here; FLAG_SYSFS just signifies that the | |
487 | * request and export were done by on behalf of userspace, so | |
488 | * they may be undone on its behalf too. | |
489 | */ | |
490 | if (test_and_clear_bit(FLAG_SYSFS, &desc->flags)) { | |
491 | status = 0; | |
492 | gpiod_free(desc); | |
493 | } | |
494 | done: | |
495 | if (status) | |
496 | pr_debug("%s: status %d\n", __func__, status); | |
497 | return status ? : len; | |
498 | } | |
499 | ||
500 | static struct class_attribute gpio_class_attrs[] = { | |
501 | __ATTR(export, 0200, NULL, export_store), | |
502 | __ATTR(unexport, 0200, NULL, unexport_store), | |
503 | __ATTR_NULL, | |
504 | }; | |
505 | ||
506 | static struct class gpio_class = { | |
507 | .name = "gpio", | |
508 | .owner = THIS_MODULE, | |
509 | ||
510 | .class_attrs = gpio_class_attrs, | |
511 | }; | |
512 | ||
513 | ||
514 | /** | |
515 | * gpiod_export - export a GPIO through sysfs | |
516 | * @gpio: gpio to make available, already requested | |
517 | * @direction_may_change: true if userspace may change gpio direction | |
518 | * Context: arch_initcall or later | |
519 | * | |
520 | * When drivers want to make a GPIO accessible to userspace after they | |
521 | * have requested it -- perhaps while debugging, or as part of their | |
522 | * public interface -- they may use this routine. If the GPIO can | |
523 | * change direction (some can't) and the caller allows it, userspace | |
524 | * will see "direction" sysfs attribute which may be used to change | |
525 | * the gpio's direction. A "value" attribute will always be provided. | |
526 | * | |
527 | * Returns zero on success, else an error. | |
528 | */ | |
529 | int gpiod_export(struct gpio_desc *desc, bool direction_may_change) | |
530 | { | |
483d8211 | 531 | struct gpio_chip *chip; |
c43960fb | 532 | struct gpiod_data *data; |
0eb4c6c2 AC |
533 | unsigned long flags; |
534 | int status; | |
535 | const char *ioname = NULL; | |
536 | struct device *dev; | |
537 | int offset; | |
538 | ||
539 | /* can't export until sysfs is available ... */ | |
540 | if (!gpio_class.p) { | |
541 | pr_debug("%s: called too early!\n", __func__); | |
542 | return -ENOENT; | |
543 | } | |
544 | ||
545 | if (!desc) { | |
546 | pr_debug("%s: invalid gpio descriptor\n", __func__); | |
547 | return -EINVAL; | |
548 | } | |
549 | ||
483d8211 JH |
550 | chip = desc->chip; |
551 | ||
0eb4c6c2 AC |
552 | mutex_lock(&sysfs_lock); |
553 | ||
483d8211 | 554 | /* check if chip is being removed */ |
6a4b6b0a | 555 | if (!chip || !chip->cdev) { |
483d8211 | 556 | status = -ENODEV; |
c43960fb | 557 | goto err_unlock; |
483d8211 JH |
558 | } |
559 | ||
0eb4c6c2 AC |
560 | spin_lock_irqsave(&gpio_lock, flags); |
561 | if (!test_bit(FLAG_REQUESTED, &desc->flags) || | |
562 | test_bit(FLAG_EXPORT, &desc->flags)) { | |
563 | spin_unlock_irqrestore(&gpio_lock, flags); | |
564 | gpiod_dbg(desc, "%s: unavailable (requested=%d, exported=%d)\n", | |
565 | __func__, | |
566 | test_bit(FLAG_REQUESTED, &desc->flags), | |
567 | test_bit(FLAG_EXPORT, &desc->flags)); | |
568 | status = -EPERM; | |
c43960fb | 569 | goto err_unlock; |
0eb4c6c2 AC |
570 | } |
571 | ||
cecf58ab | 572 | if (chip->direction_input && chip->direction_output && |
ebbeba12 JH |
573 | direction_may_change) { |
574 | set_bit(FLAG_SYSFS_DIR, &desc->flags); | |
575 | } | |
576 | ||
0eb4c6c2 AC |
577 | spin_unlock_irqrestore(&gpio_lock, flags); |
578 | ||
c43960fb JH |
579 | data = kzalloc(sizeof(*data), GFP_KERNEL); |
580 | if (!data) { | |
581 | status = -ENOMEM; | |
582 | goto err_unlock; | |
583 | } | |
584 | ||
585 | data->desc = desc; | |
586 | ||
0eb4c6c2 | 587 | offset = gpio_chip_hwgpio(desc); |
cecf58ab JH |
588 | if (chip->names && chip->names[offset]) |
589 | ioname = chip->names[offset]; | |
0eb4c6c2 | 590 | |
cecf58ab | 591 | dev = device_create_with_groups(&gpio_class, chip->dev, |
c43960fb | 592 | MKDEV(0, 0), data, gpio_groups, |
0915e6fe JH |
593 | ioname ? ioname : "gpio%u", |
594 | desc_to_gpio(desc)); | |
0eb4c6c2 AC |
595 | if (IS_ERR(dev)) { |
596 | status = PTR_ERR(dev); | |
c43960fb | 597 | goto err_free_data; |
0eb4c6c2 AC |
598 | } |
599 | ||
0eb4c6c2 AC |
600 | set_bit(FLAG_EXPORT, &desc->flags); |
601 | mutex_unlock(&sysfs_lock); | |
602 | return 0; | |
603 | ||
c43960fb JH |
604 | err_free_data: |
605 | kfree(data); | |
606 | err_unlock: | |
0eb4c6c2 AC |
607 | mutex_unlock(&sysfs_lock); |
608 | gpiod_dbg(desc, "%s: status %d\n", __func__, status); | |
609 | return status; | |
610 | } | |
611 | EXPORT_SYMBOL_GPL(gpiod_export); | |
612 | ||
c43960fb | 613 | static int match_export(struct device *dev, const void *desc) |
0eb4c6c2 | 614 | { |
c43960fb JH |
615 | struct gpiod_data *data = dev_get_drvdata(dev); |
616 | ||
617 | return data->desc == desc; | |
0eb4c6c2 AC |
618 | } |
619 | ||
620 | /** | |
621 | * gpiod_export_link - create a sysfs link to an exported GPIO node | |
622 | * @dev: device under which to create symlink | |
623 | * @name: name of the symlink | |
624 | * @gpio: gpio to create symlink to, already exported | |
625 | * | |
626 | * Set up a symlink from /sys/.../dev/name to /sys/class/gpio/gpioN | |
627 | * node. Caller is responsible for unlinking. | |
628 | * | |
629 | * Returns zero on success, else an error. | |
630 | */ | |
631 | int gpiod_export_link(struct device *dev, const char *name, | |
632 | struct gpio_desc *desc) | |
633 | { | |
634 | int status = -EINVAL; | |
635 | ||
636 | if (!desc) { | |
637 | pr_warn("%s: invalid GPIO\n", __func__); | |
638 | return -EINVAL; | |
639 | } | |
640 | ||
641 | mutex_lock(&sysfs_lock); | |
642 | ||
643 | if (test_bit(FLAG_EXPORT, &desc->flags)) { | |
644 | struct device *tdev; | |
645 | ||
646 | tdev = class_find_device(&gpio_class, NULL, desc, match_export); | |
647 | if (tdev != NULL) { | |
648 | status = sysfs_create_link(&dev->kobj, &tdev->kobj, | |
649 | name); | |
0f303db0 | 650 | put_device(tdev); |
0eb4c6c2 AC |
651 | } else { |
652 | status = -ENODEV; | |
653 | } | |
654 | } | |
655 | ||
656 | mutex_unlock(&sysfs_lock); | |
657 | ||
658 | if (status) | |
659 | gpiod_dbg(desc, "%s: status %d\n", __func__, status); | |
660 | ||
661 | return status; | |
662 | } | |
663 | EXPORT_SYMBOL_GPL(gpiod_export_link); | |
664 | ||
0eb4c6c2 AC |
665 | /** |
666 | * gpiod_unexport - reverse effect of gpio_export() | |
667 | * @gpio: gpio to make unavailable | |
668 | * | |
669 | * This is implicit on gpio_free(). | |
670 | */ | |
671 | void gpiod_unexport(struct gpio_desc *desc) | |
672 | { | |
c43960fb | 673 | struct gpiod_data *data; |
0eb4c6c2 AC |
674 | int status = 0; |
675 | struct device *dev = NULL; | |
676 | ||
677 | if (!desc) { | |
678 | pr_warn("%s: invalid GPIO\n", __func__); | |
679 | return; | |
680 | } | |
681 | ||
682 | mutex_lock(&sysfs_lock); | |
683 | ||
684 | if (test_bit(FLAG_EXPORT, &desc->flags)) { | |
685 | ||
686 | dev = class_find_device(&gpio_class, NULL, desc, match_export); | |
687 | if (dev) { | |
ebbeba12 | 688 | clear_bit(FLAG_SYSFS_DIR, &desc->flags); |
0eb4c6c2 AC |
689 | clear_bit(FLAG_EXPORT, &desc->flags); |
690 | } else | |
691 | status = -ENODEV; | |
692 | } | |
693 | ||
694 | mutex_unlock(&sysfs_lock); | |
695 | ||
696 | if (dev) { | |
c43960fb | 697 | data = dev_get_drvdata(dev); |
0eb4c6c2 | 698 | device_unregister(dev); |
54d9acd7 JH |
699 | /* |
700 | * Release irq after deregistration to prevent race with | |
701 | * edge_store. | |
702 | */ | |
b91e1807 | 703 | if (desc->flags & GPIO_TRIGGER_MASK) |
2ec74a95 | 704 | gpio_sysfs_free_irq(dev); |
0eb4c6c2 | 705 | put_device(dev); |
c43960fb | 706 | kfree(data); |
0eb4c6c2 AC |
707 | } |
708 | ||
709 | if (status) | |
710 | gpiod_dbg(desc, "%s: status %d\n", __func__, status); | |
711 | } | |
712 | EXPORT_SYMBOL_GPL(gpiod_unexport); | |
713 | ||
426577bd | 714 | int gpiochip_sysfs_register(struct gpio_chip *chip) |
0eb4c6c2 | 715 | { |
0eb4c6c2 AC |
716 | struct device *dev; |
717 | ||
426577bd JH |
718 | /* |
719 | * Many systems add gpio chips for SOC support very early, | |
0eb4c6c2 | 720 | * before driver model support is available. In those cases we |
426577bd | 721 | * register later, in gpiolib_sysfs_init() ... here we just |
0eb4c6c2 AC |
722 | * verify that _some_ field of gpio_class got initialized. |
723 | */ | |
724 | if (!gpio_class.p) | |
725 | return 0; | |
726 | ||
727 | /* use chip->base for the ID; it's already known to be unique */ | |
121b6a79 JH |
728 | dev = device_create_with_groups(&gpio_class, chip->dev, MKDEV(0, 0), |
729 | chip, gpiochip_groups, | |
730 | "gpiochip%d", chip->base); | |
731 | if (IS_ERR(dev)) | |
6a4b6b0a | 732 | return PTR_ERR(dev); |
3ff74be5 JH |
733 | |
734 | mutex_lock(&sysfs_lock); | |
6a4b6b0a | 735 | chip->cdev = dev; |
0eb4c6c2 AC |
736 | mutex_unlock(&sysfs_lock); |
737 | ||
6a4b6b0a | 738 | return 0; |
0eb4c6c2 AC |
739 | } |
740 | ||
426577bd | 741 | void gpiochip_sysfs_unregister(struct gpio_chip *chip) |
0eb4c6c2 | 742 | { |
483d8211 JH |
743 | struct gpio_desc *desc; |
744 | unsigned int i; | |
0eb4c6c2 | 745 | |
6a4b6b0a JH |
746 | if (!chip->cdev) |
747 | return; | |
0eb4c6c2 | 748 | |
6a4b6b0a JH |
749 | device_unregister(chip->cdev); |
750 | ||
751 | /* prevent further gpiod exports */ | |
752 | mutex_lock(&sysfs_lock); | |
753 | chip->cdev = NULL; | |
754 | mutex_unlock(&sysfs_lock); | |
483d8211 JH |
755 | |
756 | /* unregister gpiod class devices owned by sysfs */ | |
757 | for (i = 0; i < chip->ngpio; i++) { | |
758 | desc = &chip->desc[i]; | |
759 | if (test_and_clear_bit(FLAG_SYSFS, &desc->flags)) | |
760 | gpiod_free(desc); | |
761 | } | |
0eb4c6c2 AC |
762 | } |
763 | ||
764 | static int __init gpiolib_sysfs_init(void) | |
765 | { | |
766 | int status; | |
767 | unsigned long flags; | |
768 | struct gpio_chip *chip; | |
769 | ||
770 | status = class_register(&gpio_class); | |
771 | if (status < 0) | |
772 | return status; | |
773 | ||
774 | /* Scan and register the gpio_chips which registered very | |
775 | * early (e.g. before the class_register above was called). | |
776 | * | |
777 | * We run before arch_initcall() so chip->dev nodes can have | |
778 | * registered, and so arch_initcall() can always gpio_export(). | |
779 | */ | |
780 | spin_lock_irqsave(&gpio_lock, flags); | |
781 | list_for_each_entry(chip, &gpio_chips, list) { | |
6a4b6b0a | 782 | if (chip->cdev) |
0eb4c6c2 AC |
783 | continue; |
784 | ||
14141a93 | 785 | /* |
426577bd JH |
786 | * TODO we yield gpio_lock here because |
787 | * gpiochip_sysfs_register() acquires a mutex. This is unsafe | |
788 | * and needs to be fixed. | |
14141a93 AC |
789 | * |
790 | * Also it would be nice to use gpiochip_find() here so we | |
791 | * can keep gpio_chips local to gpiolib.c, but the yield of | |
792 | * gpio_lock prevents us from doing this. | |
793 | */ | |
0eb4c6c2 | 794 | spin_unlock_irqrestore(&gpio_lock, flags); |
426577bd | 795 | status = gpiochip_sysfs_register(chip); |
0eb4c6c2 AC |
796 | spin_lock_irqsave(&gpio_lock, flags); |
797 | } | |
798 | spin_unlock_irqrestore(&gpio_lock, flags); | |
799 | ||
800 | ||
801 | return status; | |
802 | } | |
803 | postcore_initcall(gpiolib_sysfs_init); |