Commit | Line | Data |
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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; | |
6ffcb797 JH |
15 | |
16 | struct mutex mutex; | |
a08f5c21 | 17 | struct kernfs_node *value_kn; |
2ec74a95 | 18 | int irq; |
c43960fb JH |
19 | }; |
20 | ||
6ffcb797 JH |
21 | /* |
22 | * Lock to serialise gpiod export and unexport, and prevent re-export of | |
23 | * gpiod whose chip is being unregistered. | |
0eb4c6c2 AC |
24 | */ |
25 | static DEFINE_MUTEX(sysfs_lock); | |
26 | ||
27 | /* | |
28 | * /sys/class/gpio/gpioN... only for GPIOs that are exported | |
29 | * /direction | |
30 | * * MAY BE OMITTED if kernel won't allow direction changes | |
31 | * * is read/write as "in" or "out" | |
32 | * * may also be written as "high" or "low", initializing | |
33 | * output value as specified ("out" implies "low") | |
34 | * /value | |
35 | * * always readable, subject to hardware behavior | |
36 | * * may be writable, as zero/nonzero | |
37 | * /edge | |
38 | * * configures behavior of poll(2) on /value | |
39 | * * available only if pin can generate IRQs on input | |
40 | * * is read/write as "none", "falling", "rising", or "both" | |
41 | * /active_low | |
42 | * * configures polarity of /value | |
43 | * * is read/write as zero/nonzero | |
44 | * * also affects existing and subsequent "falling" and "rising" | |
45 | * /edge configuration | |
46 | */ | |
47 | ||
6beac9d1 | 48 | static ssize_t direction_show(struct device *dev, |
0eb4c6c2 AC |
49 | struct device_attribute *attr, char *buf) |
50 | { | |
c43960fb JH |
51 | struct gpiod_data *data = dev_get_drvdata(dev); |
52 | struct gpio_desc *desc = data->desc; | |
0eb4c6c2 AC |
53 | ssize_t status; |
54 | ||
6ffcb797 | 55 | mutex_lock(&data->mutex); |
0eb4c6c2 | 56 | |
f0b7866a JH |
57 | gpiod_get_direction(desc); |
58 | status = sprintf(buf, "%s\n", | |
0eb4c6c2 AC |
59 | test_bit(FLAG_IS_OUT, &desc->flags) |
60 | ? "out" : "in"); | |
0eb4c6c2 | 61 | |
6ffcb797 JH |
62 | mutex_unlock(&data->mutex); |
63 | ||
0eb4c6c2 AC |
64 | return status; |
65 | } | |
66 | ||
6beac9d1 | 67 | static ssize_t direction_store(struct device *dev, |
0eb4c6c2 AC |
68 | struct device_attribute *attr, const char *buf, size_t size) |
69 | { | |
c43960fb JH |
70 | struct gpiod_data *data = dev_get_drvdata(dev); |
71 | struct gpio_desc *desc = data->desc; | |
0eb4c6c2 AC |
72 | ssize_t status; |
73 | ||
6ffcb797 | 74 | mutex_lock(&data->mutex); |
0eb4c6c2 | 75 | |
f0b7866a | 76 | if (sysfs_streq(buf, "high")) |
0eb4c6c2 AC |
77 | status = gpiod_direction_output_raw(desc, 1); |
78 | else if (sysfs_streq(buf, "out") || sysfs_streq(buf, "low")) | |
79 | status = gpiod_direction_output_raw(desc, 0); | |
80 | else if (sysfs_streq(buf, "in")) | |
81 | status = gpiod_direction_input(desc); | |
82 | else | |
83 | status = -EINVAL; | |
84 | ||
6ffcb797 JH |
85 | mutex_unlock(&data->mutex); |
86 | ||
0eb4c6c2 AC |
87 | return status ? : size; |
88 | } | |
6beac9d1 | 89 | static DEVICE_ATTR_RW(direction); |
0eb4c6c2 | 90 | |
6beac9d1 | 91 | static ssize_t value_show(struct device *dev, |
0eb4c6c2 AC |
92 | struct device_attribute *attr, char *buf) |
93 | { | |
c43960fb JH |
94 | struct gpiod_data *data = dev_get_drvdata(dev); |
95 | struct gpio_desc *desc = data->desc; | |
0eb4c6c2 AC |
96 | ssize_t status; |
97 | ||
6ffcb797 | 98 | mutex_lock(&data->mutex); |
0eb4c6c2 | 99 | |
f0b7866a | 100 | status = sprintf(buf, "%d\n", gpiod_get_value_cansleep(desc)); |
0eb4c6c2 | 101 | |
6ffcb797 JH |
102 | mutex_unlock(&data->mutex); |
103 | ||
0eb4c6c2 AC |
104 | return status; |
105 | } | |
106 | ||
6beac9d1 | 107 | static ssize_t value_store(struct device *dev, |
0eb4c6c2 AC |
108 | struct device_attribute *attr, const char *buf, size_t size) |
109 | { | |
c43960fb JH |
110 | struct gpiod_data *data = dev_get_drvdata(dev); |
111 | struct gpio_desc *desc = data->desc; | |
0eb4c6c2 AC |
112 | ssize_t status; |
113 | ||
6ffcb797 | 114 | mutex_lock(&data->mutex); |
0eb4c6c2 | 115 | |
f0b7866a | 116 | if (!test_bit(FLAG_IS_OUT, &desc->flags)) { |
0eb4c6c2 | 117 | status = -EPERM; |
f0b7866a | 118 | } else { |
0eb4c6c2 AC |
119 | long value; |
120 | ||
121 | status = kstrtol(buf, 0, &value); | |
122 | if (status == 0) { | |
123 | gpiod_set_value_cansleep(desc, value); | |
124 | status = size; | |
125 | } | |
126 | } | |
127 | ||
6ffcb797 JH |
128 | mutex_unlock(&data->mutex); |
129 | ||
0eb4c6c2 AC |
130 | return status; |
131 | } | |
6beac9d1 | 132 | static DEVICE_ATTR_RW(value); |
0eb4c6c2 AC |
133 | |
134 | static irqreturn_t gpio_sysfs_irq(int irq, void *priv) | |
135 | { | |
a08f5c21 JH |
136 | struct gpiod_data *data = priv; |
137 | ||
138 | sysfs_notify_dirent(data->value_kn); | |
0eb4c6c2 | 139 | |
0eb4c6c2 AC |
140 | return IRQ_HANDLED; |
141 | } | |
142 | ||
6ffcb797 | 143 | /* Caller holds gpiod-data mutex. */ |
2ec74a95 | 144 | static int gpio_sysfs_request_irq(struct device *dev, unsigned long gpio_flags) |
0eb4c6c2 | 145 | { |
0f628508 JH |
146 | struct gpiod_data *data = dev_get_drvdata(dev); |
147 | struct gpio_desc *desc = data->desc; | |
0eb4c6c2 | 148 | unsigned long irq_flags; |
2ec74a95 | 149 | int ret; |
0eb4c6c2 | 150 | |
2ec74a95 JH |
151 | data->irq = gpiod_to_irq(desc); |
152 | if (data->irq < 0) | |
0eb4c6c2 AC |
153 | return -EIO; |
154 | ||
2ec74a95 JH |
155 | data->value_kn = sysfs_get_dirent(dev->kobj.sd, "value"); |
156 | if (!data->value_kn) | |
157 | return -ENODEV; | |
0eb4c6c2 AC |
158 | |
159 | irq_flags = IRQF_SHARED; | |
160 | if (test_bit(FLAG_TRIG_FALL, &gpio_flags)) | |
161 | irq_flags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ? | |
162 | IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING; | |
163 | if (test_bit(FLAG_TRIG_RISE, &gpio_flags)) | |
164 | irq_flags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ? | |
165 | IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING; | |
166 | ||
52176d0d JH |
167 | /* |
168 | * FIXME: This should be done in the irq_request_resources callback | |
169 | * when the irq is requested, but a few drivers currently fail | |
170 | * to do so. | |
171 | * | |
172 | * Remove this redundant call (along with the corresponding | |
173 | * unlock) when those drivers have been fixed. | |
174 | */ | |
175 | ret = gpiochip_lock_as_irq(desc->chip, gpio_chip_hwgpio(desc)); | |
0eb4c6c2 | 176 | if (ret < 0) |
2ec74a95 | 177 | goto err_put_kn; |
0eb4c6c2 | 178 | |
2ec74a95 | 179 | ret = request_any_context_irq(data->irq, gpio_sysfs_irq, irq_flags, |
a08f5c21 | 180 | "gpiolib", data); |
52176d0d JH |
181 | if (ret < 0) |
182 | goto err_unlock; | |
0eb4c6c2 AC |
183 | |
184 | desc->flags |= gpio_flags; | |
2ec74a95 | 185 | |
0eb4c6c2 AC |
186 | return 0; |
187 | ||
52176d0d JH |
188 | err_unlock: |
189 | gpiochip_unlock_as_irq(desc->chip, gpio_chip_hwgpio(desc)); | |
2ec74a95 JH |
190 | err_put_kn: |
191 | sysfs_put(data->value_kn); | |
192 | ||
0eb4c6c2 AC |
193 | return ret; |
194 | } | |
195 | ||
6ffcb797 JH |
196 | /* |
197 | * Caller holds gpiod-data mutex (unless called after class-device | |
198 | * deregistration). | |
199 | */ | |
2ec74a95 JH |
200 | static void gpio_sysfs_free_irq(struct device *dev) |
201 | { | |
202 | struct gpiod_data *data = dev_get_drvdata(dev); | |
203 | struct gpio_desc *desc = data->desc; | |
204 | ||
205 | desc->flags &= ~GPIO_TRIGGER_MASK; | |
206 | free_irq(data->irq, data); | |
207 | gpiochip_unlock_as_irq(desc->chip, gpio_chip_hwgpio(desc)); | |
208 | sysfs_put(data->value_kn); | |
209 | } | |
210 | ||
0eb4c6c2 AC |
211 | static const struct { |
212 | const char *name; | |
213 | unsigned long flags; | |
214 | } trigger_types[] = { | |
215 | { "none", 0 }, | |
216 | { "falling", BIT(FLAG_TRIG_FALL) }, | |
217 | { "rising", BIT(FLAG_TRIG_RISE) }, | |
218 | { "both", BIT(FLAG_TRIG_FALL) | BIT(FLAG_TRIG_RISE) }, | |
219 | }; | |
220 | ||
6beac9d1 | 221 | static ssize_t edge_show(struct device *dev, |
0eb4c6c2 AC |
222 | struct device_attribute *attr, char *buf) |
223 | { | |
c43960fb JH |
224 | struct gpiod_data *data = dev_get_drvdata(dev); |
225 | struct gpio_desc *desc = data->desc; | |
f0b7866a JH |
226 | unsigned long mask; |
227 | ssize_t status = 0; | |
228 | int i; | |
0eb4c6c2 | 229 | |
6ffcb797 | 230 | mutex_lock(&data->mutex); |
0eb4c6c2 | 231 | |
f0b7866a JH |
232 | for (i = 0; i < ARRAY_SIZE(trigger_types); i++) { |
233 | mask = desc->flags & GPIO_TRIGGER_MASK; | |
234 | if (mask == trigger_types[i].flags) { | |
235 | status = sprintf(buf, "%s\n", trigger_types[i].name); | |
236 | break; | |
237 | } | |
0eb4c6c2 AC |
238 | } |
239 | ||
6ffcb797 JH |
240 | mutex_unlock(&data->mutex); |
241 | ||
0eb4c6c2 AC |
242 | return status; |
243 | } | |
244 | ||
6beac9d1 | 245 | static ssize_t edge_store(struct device *dev, |
0eb4c6c2 AC |
246 | struct device_attribute *attr, const char *buf, size_t size) |
247 | { | |
b91e1807 JH |
248 | struct gpiod_data *data = dev_get_drvdata(dev); |
249 | struct gpio_desc *desc = data->desc; | |
250 | unsigned long flags; | |
2ec74a95 | 251 | ssize_t status = size; |
e4339ce3 | 252 | int i; |
0eb4c6c2 | 253 | |
e4339ce3 | 254 | for (i = 0; i < ARRAY_SIZE(trigger_types); i++) { |
0eb4c6c2 | 255 | if (sysfs_streq(trigger_types[i].name, buf)) |
e4339ce3 JH |
256 | break; |
257 | } | |
258 | ||
259 | if (i == ARRAY_SIZE(trigger_types)) | |
260 | return -EINVAL; | |
0eb4c6c2 | 261 | |
b91e1807 JH |
262 | flags = trigger_types[i].flags; |
263 | ||
6ffcb797 | 264 | mutex_lock(&data->mutex); |
0eb4c6c2 | 265 | |
b91e1807 JH |
266 | if ((desc->flags & GPIO_TRIGGER_MASK) == flags) { |
267 | status = size; | |
268 | goto out_unlock; | |
269 | } | |
270 | ||
2ec74a95 JH |
271 | if (desc->flags & GPIO_TRIGGER_MASK) |
272 | gpio_sysfs_free_irq(dev); | |
273 | ||
274 | if (flags) { | |
275 | status = gpio_sysfs_request_irq(dev, flags); | |
276 | if (!status) | |
277 | status = size; | |
278 | } | |
0eb4c6c2 | 279 | |
b91e1807 | 280 | out_unlock: |
6ffcb797 | 281 | mutex_unlock(&data->mutex); |
0eb4c6c2 AC |
282 | |
283 | return status; | |
284 | } | |
6beac9d1 | 285 | static DEVICE_ATTR_RW(edge); |
0eb4c6c2 | 286 | |
6ffcb797 | 287 | /* Caller holds gpiod-data mutex. */ |
2f323b85 | 288 | static int gpio_sysfs_set_active_low(struct device *dev, int value) |
0eb4c6c2 | 289 | { |
0f628508 JH |
290 | struct gpiod_data *data = dev_get_drvdata(dev); |
291 | struct gpio_desc *desc = data->desc; | |
0eb4c6c2 AC |
292 | int status = 0; |
293 | ||
294 | if (!!test_bit(FLAG_ACTIVE_LOW, &desc->flags) == !!value) | |
295 | return 0; | |
296 | ||
297 | if (value) | |
298 | set_bit(FLAG_ACTIVE_LOW, &desc->flags); | |
299 | else | |
300 | clear_bit(FLAG_ACTIVE_LOW, &desc->flags); | |
301 | ||
302 | /* reconfigure poll(2) support if enabled on one edge only */ | |
166a85e4 JH |
303 | if (!!test_bit(FLAG_TRIG_RISE, &desc->flags) ^ |
304 | !!test_bit(FLAG_TRIG_FALL, &desc->flags)) { | |
0eb4c6c2 AC |
305 | unsigned long trigger_flags = desc->flags & GPIO_TRIGGER_MASK; |
306 | ||
2ec74a95 JH |
307 | gpio_sysfs_free_irq(dev); |
308 | status = gpio_sysfs_request_irq(dev, trigger_flags); | |
0eb4c6c2 AC |
309 | } |
310 | ||
311 | return status; | |
312 | } | |
313 | ||
6beac9d1 | 314 | static ssize_t active_low_show(struct device *dev, |
0eb4c6c2 AC |
315 | struct device_attribute *attr, char *buf) |
316 | { | |
c43960fb JH |
317 | struct gpiod_data *data = dev_get_drvdata(dev); |
318 | struct gpio_desc *desc = data->desc; | |
0eb4c6c2 AC |
319 | ssize_t status; |
320 | ||
6ffcb797 | 321 | mutex_lock(&data->mutex); |
0eb4c6c2 | 322 | |
f0b7866a | 323 | status = sprintf(buf, "%d\n", |
0eb4c6c2 AC |
324 | !!test_bit(FLAG_ACTIVE_LOW, &desc->flags)); |
325 | ||
6ffcb797 | 326 | mutex_unlock(&data->mutex); |
0eb4c6c2 AC |
327 | |
328 | return status; | |
329 | } | |
330 | ||
6beac9d1 | 331 | static ssize_t active_low_store(struct device *dev, |
0eb4c6c2 AC |
332 | struct device_attribute *attr, const char *buf, size_t size) |
333 | { | |
6ffcb797 | 334 | struct gpiod_data *data = dev_get_drvdata(dev); |
0eb4c6c2 | 335 | ssize_t status; |
f0b7866a | 336 | long value; |
0eb4c6c2 | 337 | |
6ffcb797 | 338 | mutex_lock(&data->mutex); |
0eb4c6c2 | 339 | |
f0b7866a JH |
340 | status = kstrtol(buf, 0, &value); |
341 | if (status == 0) | |
2f323b85 | 342 | status = gpio_sysfs_set_active_low(dev, value); |
0eb4c6c2 | 343 | |
6ffcb797 | 344 | mutex_unlock(&data->mutex); |
0eb4c6c2 AC |
345 | |
346 | return status ? : size; | |
347 | } | |
6beac9d1 | 348 | static DEVICE_ATTR_RW(active_low); |
0eb4c6c2 | 349 | |
ebbeba12 JH |
350 | static umode_t gpio_is_visible(struct kobject *kobj, struct attribute *attr, |
351 | int n) | |
352 | { | |
353 | struct device *dev = container_of(kobj, struct device, kobj); | |
c43960fb JH |
354 | struct gpiod_data *data = dev_get_drvdata(dev); |
355 | struct gpio_desc *desc = data->desc; | |
ebbeba12 JH |
356 | umode_t mode = attr->mode; |
357 | bool show_direction = test_bit(FLAG_SYSFS_DIR, &desc->flags); | |
358 | ||
359 | if (attr == &dev_attr_direction.attr) { | |
360 | if (!show_direction) | |
361 | mode = 0; | |
362 | } else if (attr == &dev_attr_edge.attr) { | |
363 | if (gpiod_to_irq(desc) < 0) | |
364 | mode = 0; | |
365 | if (!show_direction && test_bit(FLAG_IS_OUT, &desc->flags)) | |
366 | mode = 0; | |
367 | } | |
368 | ||
369 | return mode; | |
370 | } | |
371 | ||
0915e6fe | 372 | static struct attribute *gpio_attrs[] = { |
ebbeba12 JH |
373 | &dev_attr_direction.attr, |
374 | &dev_attr_edge.attr, | |
0eb4c6c2 AC |
375 | &dev_attr_value.attr, |
376 | &dev_attr_active_low.attr, | |
377 | NULL, | |
378 | }; | |
ebbeba12 JH |
379 | |
380 | static const struct attribute_group gpio_group = { | |
381 | .attrs = gpio_attrs, | |
382 | .is_visible = gpio_is_visible, | |
383 | }; | |
384 | ||
385 | static const struct attribute_group *gpio_groups[] = { | |
386 | &gpio_group, | |
387 | NULL | |
388 | }; | |
0eb4c6c2 AC |
389 | |
390 | /* | |
391 | * /sys/class/gpio/gpiochipN/ | |
392 | * /base ... matching gpio_chip.base (N) | |
393 | * /label ... matching gpio_chip.label | |
394 | * /ngpio ... matching gpio_chip.ngpio | |
395 | */ | |
396 | ||
6beac9d1 | 397 | static ssize_t base_show(struct device *dev, |
0eb4c6c2 AC |
398 | struct device_attribute *attr, char *buf) |
399 | { | |
400 | const struct gpio_chip *chip = dev_get_drvdata(dev); | |
401 | ||
402 | return sprintf(buf, "%d\n", chip->base); | |
403 | } | |
6beac9d1 | 404 | static DEVICE_ATTR_RO(base); |
0eb4c6c2 | 405 | |
6beac9d1 | 406 | static ssize_t label_show(struct device *dev, |
0eb4c6c2 AC |
407 | struct device_attribute *attr, char *buf) |
408 | { | |
409 | const struct gpio_chip *chip = dev_get_drvdata(dev); | |
410 | ||
411 | return sprintf(buf, "%s\n", chip->label ? : ""); | |
412 | } | |
6beac9d1 | 413 | static DEVICE_ATTR_RO(label); |
0eb4c6c2 | 414 | |
6beac9d1 | 415 | static ssize_t ngpio_show(struct device *dev, |
0eb4c6c2 AC |
416 | struct device_attribute *attr, char *buf) |
417 | { | |
418 | const struct gpio_chip *chip = dev_get_drvdata(dev); | |
419 | ||
420 | return sprintf(buf, "%u\n", chip->ngpio); | |
421 | } | |
6beac9d1 | 422 | static DEVICE_ATTR_RO(ngpio); |
0eb4c6c2 | 423 | |
121b6a79 | 424 | static struct attribute *gpiochip_attrs[] = { |
0eb4c6c2 AC |
425 | &dev_attr_base.attr, |
426 | &dev_attr_label.attr, | |
427 | &dev_attr_ngpio.attr, | |
428 | NULL, | |
429 | }; | |
121b6a79 | 430 | ATTRIBUTE_GROUPS(gpiochip); |
0eb4c6c2 AC |
431 | |
432 | /* | |
433 | * /sys/class/gpio/export ... write-only | |
434 | * integer N ... number of GPIO to export (full access) | |
435 | * /sys/class/gpio/unexport ... write-only | |
436 | * integer N ... number of GPIO to unexport | |
437 | */ | |
438 | static ssize_t export_store(struct class *class, | |
439 | struct class_attribute *attr, | |
440 | const char *buf, size_t len) | |
441 | { | |
442 | long gpio; | |
443 | struct gpio_desc *desc; | |
444 | int status; | |
445 | ||
446 | status = kstrtol(buf, 0, &gpio); | |
447 | if (status < 0) | |
448 | goto done; | |
449 | ||
450 | desc = gpio_to_desc(gpio); | |
451 | /* reject invalid GPIOs */ | |
452 | if (!desc) { | |
453 | pr_warn("%s: invalid GPIO %ld\n", __func__, gpio); | |
454 | return -EINVAL; | |
455 | } | |
456 | ||
457 | /* No extra locking here; FLAG_SYSFS just signifies that the | |
458 | * request and export were done by on behalf of userspace, so | |
459 | * they may be undone on its behalf too. | |
460 | */ | |
461 | ||
462 | status = gpiod_request(desc, "sysfs"); | |
463 | if (status < 0) { | |
464 | if (status == -EPROBE_DEFER) | |
465 | status = -ENODEV; | |
466 | goto done; | |
467 | } | |
468 | status = gpiod_export(desc, true); | |
469 | if (status < 0) | |
470 | gpiod_free(desc); | |
471 | else | |
472 | set_bit(FLAG_SYSFS, &desc->flags); | |
473 | ||
474 | done: | |
475 | if (status) | |
476 | pr_debug("%s: status %d\n", __func__, status); | |
477 | return status ? : len; | |
478 | } | |
479 | ||
480 | static ssize_t unexport_store(struct class *class, | |
481 | struct class_attribute *attr, | |
482 | const char *buf, size_t len) | |
483 | { | |
484 | long gpio; | |
485 | struct gpio_desc *desc; | |
486 | int status; | |
487 | ||
488 | status = kstrtol(buf, 0, &gpio); | |
489 | if (status < 0) | |
490 | goto done; | |
491 | ||
492 | desc = gpio_to_desc(gpio); | |
493 | /* reject bogus commands (gpio_unexport ignores them) */ | |
494 | if (!desc) { | |
495 | pr_warn("%s: invalid GPIO %ld\n", __func__, gpio); | |
496 | return -EINVAL; | |
497 | } | |
498 | ||
499 | status = -EINVAL; | |
500 | ||
501 | /* No extra locking here; FLAG_SYSFS just signifies that the | |
502 | * request and export were done by on behalf of userspace, so | |
503 | * they may be undone on its behalf too. | |
504 | */ | |
505 | if (test_and_clear_bit(FLAG_SYSFS, &desc->flags)) { | |
506 | status = 0; | |
507 | gpiod_free(desc); | |
508 | } | |
509 | done: | |
510 | if (status) | |
511 | pr_debug("%s: status %d\n", __func__, status); | |
512 | return status ? : len; | |
513 | } | |
514 | ||
515 | static struct class_attribute gpio_class_attrs[] = { | |
516 | __ATTR(export, 0200, NULL, export_store), | |
517 | __ATTR(unexport, 0200, NULL, unexport_store), | |
518 | __ATTR_NULL, | |
519 | }; | |
520 | ||
521 | static struct class gpio_class = { | |
522 | .name = "gpio", | |
523 | .owner = THIS_MODULE, | |
524 | ||
525 | .class_attrs = gpio_class_attrs, | |
526 | }; | |
527 | ||
528 | ||
529 | /** | |
530 | * gpiod_export - export a GPIO through sysfs | |
531 | * @gpio: gpio to make available, already requested | |
532 | * @direction_may_change: true if userspace may change gpio direction | |
533 | * Context: arch_initcall or later | |
534 | * | |
535 | * When drivers want to make a GPIO accessible to userspace after they | |
536 | * have requested it -- perhaps while debugging, or as part of their | |
537 | * public interface -- they may use this routine. If the GPIO can | |
538 | * change direction (some can't) and the caller allows it, userspace | |
539 | * will see "direction" sysfs attribute which may be used to change | |
540 | * the gpio's direction. A "value" attribute will always be provided. | |
541 | * | |
542 | * Returns zero on success, else an error. | |
543 | */ | |
544 | int gpiod_export(struct gpio_desc *desc, bool direction_may_change) | |
545 | { | |
483d8211 | 546 | struct gpio_chip *chip; |
c43960fb | 547 | struct gpiod_data *data; |
0eb4c6c2 AC |
548 | unsigned long flags; |
549 | int status; | |
550 | const char *ioname = NULL; | |
551 | struct device *dev; | |
552 | int offset; | |
553 | ||
554 | /* can't export until sysfs is available ... */ | |
555 | if (!gpio_class.p) { | |
556 | pr_debug("%s: called too early!\n", __func__); | |
557 | return -ENOENT; | |
558 | } | |
559 | ||
560 | if (!desc) { | |
561 | pr_debug("%s: invalid gpio descriptor\n", __func__); | |
562 | return -EINVAL; | |
563 | } | |
564 | ||
483d8211 JH |
565 | chip = desc->chip; |
566 | ||
0eb4c6c2 AC |
567 | mutex_lock(&sysfs_lock); |
568 | ||
483d8211 | 569 | /* check if chip is being removed */ |
6a4b6b0a | 570 | if (!chip || !chip->cdev) { |
483d8211 | 571 | status = -ENODEV; |
c43960fb | 572 | goto err_unlock; |
483d8211 JH |
573 | } |
574 | ||
0eb4c6c2 AC |
575 | spin_lock_irqsave(&gpio_lock, flags); |
576 | if (!test_bit(FLAG_REQUESTED, &desc->flags) || | |
577 | test_bit(FLAG_EXPORT, &desc->flags)) { | |
578 | spin_unlock_irqrestore(&gpio_lock, flags); | |
579 | gpiod_dbg(desc, "%s: unavailable (requested=%d, exported=%d)\n", | |
580 | __func__, | |
581 | test_bit(FLAG_REQUESTED, &desc->flags), | |
582 | test_bit(FLAG_EXPORT, &desc->flags)); | |
583 | status = -EPERM; | |
c43960fb | 584 | goto err_unlock; |
0eb4c6c2 AC |
585 | } |
586 | ||
cecf58ab | 587 | if (chip->direction_input && chip->direction_output && |
ebbeba12 JH |
588 | direction_may_change) { |
589 | set_bit(FLAG_SYSFS_DIR, &desc->flags); | |
590 | } | |
591 | ||
0eb4c6c2 AC |
592 | spin_unlock_irqrestore(&gpio_lock, flags); |
593 | ||
c43960fb JH |
594 | data = kzalloc(sizeof(*data), GFP_KERNEL); |
595 | if (!data) { | |
596 | status = -ENOMEM; | |
597 | goto err_unlock; | |
598 | } | |
599 | ||
600 | data->desc = desc; | |
6ffcb797 | 601 | mutex_init(&data->mutex); |
c43960fb | 602 | |
0eb4c6c2 | 603 | offset = gpio_chip_hwgpio(desc); |
cecf58ab JH |
604 | if (chip->names && chip->names[offset]) |
605 | ioname = chip->names[offset]; | |
0eb4c6c2 | 606 | |
cecf58ab | 607 | dev = device_create_with_groups(&gpio_class, chip->dev, |
c43960fb | 608 | MKDEV(0, 0), data, gpio_groups, |
0915e6fe JH |
609 | ioname ? ioname : "gpio%u", |
610 | desc_to_gpio(desc)); | |
0eb4c6c2 AC |
611 | if (IS_ERR(dev)) { |
612 | status = PTR_ERR(dev); | |
c43960fb | 613 | goto err_free_data; |
0eb4c6c2 AC |
614 | } |
615 | ||
0eb4c6c2 AC |
616 | set_bit(FLAG_EXPORT, &desc->flags); |
617 | mutex_unlock(&sysfs_lock); | |
618 | return 0; | |
619 | ||
c43960fb JH |
620 | err_free_data: |
621 | kfree(data); | |
622 | err_unlock: | |
0eb4c6c2 AC |
623 | mutex_unlock(&sysfs_lock); |
624 | gpiod_dbg(desc, "%s: status %d\n", __func__, status); | |
625 | return status; | |
626 | } | |
627 | EXPORT_SYMBOL_GPL(gpiod_export); | |
628 | ||
c43960fb | 629 | static int match_export(struct device *dev, const void *desc) |
0eb4c6c2 | 630 | { |
c43960fb JH |
631 | struct gpiod_data *data = dev_get_drvdata(dev); |
632 | ||
633 | return data->desc == desc; | |
0eb4c6c2 AC |
634 | } |
635 | ||
636 | /** | |
637 | * gpiod_export_link - create a sysfs link to an exported GPIO node | |
638 | * @dev: device under which to create symlink | |
639 | * @name: name of the symlink | |
640 | * @gpio: gpio to create symlink to, already exported | |
641 | * | |
642 | * Set up a symlink from /sys/.../dev/name to /sys/class/gpio/gpioN | |
643 | * node. Caller is responsible for unlinking. | |
644 | * | |
645 | * Returns zero on success, else an error. | |
646 | */ | |
647 | int gpiod_export_link(struct device *dev, const char *name, | |
648 | struct gpio_desc *desc) | |
649 | { | |
56d30ec1 JH |
650 | struct device *cdev; |
651 | int ret; | |
0eb4c6c2 AC |
652 | |
653 | if (!desc) { | |
654 | pr_warn("%s: invalid GPIO\n", __func__); | |
655 | return -EINVAL; | |
656 | } | |
657 | ||
56d30ec1 JH |
658 | cdev = class_find_device(&gpio_class, NULL, desc, match_export); |
659 | if (!cdev) | |
660 | return -ENODEV; | |
0eb4c6c2 | 661 | |
56d30ec1 JH |
662 | ret = sysfs_create_link(&dev->kobj, &cdev->kobj, name); |
663 | put_device(cdev); | |
0eb4c6c2 | 664 | |
56d30ec1 | 665 | return ret; |
0eb4c6c2 AC |
666 | } |
667 | EXPORT_SYMBOL_GPL(gpiod_export_link); | |
668 | ||
0eb4c6c2 AC |
669 | /** |
670 | * gpiod_unexport - reverse effect of gpio_export() | |
671 | * @gpio: gpio to make unavailable | |
672 | * | |
673 | * This is implicit on gpio_free(). | |
674 | */ | |
675 | void gpiod_unexport(struct gpio_desc *desc) | |
676 | { | |
72eba6f6 JH |
677 | struct gpiod_data *data; |
678 | struct device *dev; | |
0eb4c6c2 AC |
679 | |
680 | if (!desc) { | |
681 | pr_warn("%s: invalid GPIO\n", __func__); | |
682 | return; | |
683 | } | |
684 | ||
685 | mutex_lock(&sysfs_lock); | |
686 | ||
72eba6f6 JH |
687 | if (!test_bit(FLAG_EXPORT, &desc->flags)) |
688 | goto err_unlock; | |
0eb4c6c2 | 689 | |
72eba6f6 JH |
690 | dev = class_find_device(&gpio_class, NULL, desc, match_export); |
691 | if (!dev) | |
692 | goto err_unlock; | |
693 | ||
694 | data = dev_get_drvdata(dev); | |
695 | ||
696 | clear_bit(FLAG_SYSFS_DIR, &desc->flags); | |
697 | clear_bit(FLAG_EXPORT, &desc->flags); | |
698 | ||
699 | device_unregister(dev); | |
700 | ||
701 | /* | |
702 | * Release irq after deregistration to prevent race with edge_store. | |
703 | */ | |
704 | if (desc->flags & GPIO_TRIGGER_MASK) | |
705 | gpio_sysfs_free_irq(dev); | |
0eb4c6c2 AC |
706 | |
707 | mutex_unlock(&sysfs_lock); | |
708 | ||
72eba6f6 JH |
709 | put_device(dev); |
710 | kfree(data); | |
0eb4c6c2 | 711 | |
72eba6f6 JH |
712 | return; |
713 | ||
714 | err_unlock: | |
715 | mutex_unlock(&sysfs_lock); | |
0eb4c6c2 AC |
716 | } |
717 | EXPORT_SYMBOL_GPL(gpiod_unexport); | |
718 | ||
426577bd | 719 | int gpiochip_sysfs_register(struct gpio_chip *chip) |
0eb4c6c2 | 720 | { |
0eb4c6c2 AC |
721 | struct device *dev; |
722 | ||
426577bd JH |
723 | /* |
724 | * Many systems add gpio chips for SOC support very early, | |
0eb4c6c2 | 725 | * before driver model support is available. In those cases we |
426577bd | 726 | * register later, in gpiolib_sysfs_init() ... here we just |
0eb4c6c2 AC |
727 | * verify that _some_ field of gpio_class got initialized. |
728 | */ | |
729 | if (!gpio_class.p) | |
730 | return 0; | |
731 | ||
732 | /* use chip->base for the ID; it's already known to be unique */ | |
121b6a79 JH |
733 | dev = device_create_with_groups(&gpio_class, chip->dev, MKDEV(0, 0), |
734 | chip, gpiochip_groups, | |
735 | "gpiochip%d", chip->base); | |
736 | if (IS_ERR(dev)) | |
6a4b6b0a | 737 | return PTR_ERR(dev); |
3ff74be5 JH |
738 | |
739 | mutex_lock(&sysfs_lock); | |
6a4b6b0a | 740 | chip->cdev = dev; |
0eb4c6c2 AC |
741 | mutex_unlock(&sysfs_lock); |
742 | ||
6a4b6b0a | 743 | return 0; |
0eb4c6c2 AC |
744 | } |
745 | ||
426577bd | 746 | void gpiochip_sysfs_unregister(struct gpio_chip *chip) |
0eb4c6c2 | 747 | { |
483d8211 JH |
748 | struct gpio_desc *desc; |
749 | unsigned int i; | |
0eb4c6c2 | 750 | |
6a4b6b0a JH |
751 | if (!chip->cdev) |
752 | return; | |
0eb4c6c2 | 753 | |
6a4b6b0a JH |
754 | device_unregister(chip->cdev); |
755 | ||
756 | /* prevent further gpiod exports */ | |
757 | mutex_lock(&sysfs_lock); | |
758 | chip->cdev = NULL; | |
759 | mutex_unlock(&sysfs_lock); | |
483d8211 JH |
760 | |
761 | /* unregister gpiod class devices owned by sysfs */ | |
762 | for (i = 0; i < chip->ngpio; i++) { | |
763 | desc = &chip->desc[i]; | |
764 | if (test_and_clear_bit(FLAG_SYSFS, &desc->flags)) | |
765 | gpiod_free(desc); | |
766 | } | |
0eb4c6c2 AC |
767 | } |
768 | ||
769 | static int __init gpiolib_sysfs_init(void) | |
770 | { | |
771 | int status; | |
772 | unsigned long flags; | |
773 | struct gpio_chip *chip; | |
774 | ||
775 | status = class_register(&gpio_class); | |
776 | if (status < 0) | |
777 | return status; | |
778 | ||
779 | /* Scan and register the gpio_chips which registered very | |
780 | * early (e.g. before the class_register above was called). | |
781 | * | |
782 | * We run before arch_initcall() so chip->dev nodes can have | |
783 | * registered, and so arch_initcall() can always gpio_export(). | |
784 | */ | |
785 | spin_lock_irqsave(&gpio_lock, flags); | |
786 | list_for_each_entry(chip, &gpio_chips, list) { | |
6a4b6b0a | 787 | if (chip->cdev) |
0eb4c6c2 AC |
788 | continue; |
789 | ||
14141a93 | 790 | /* |
426577bd JH |
791 | * TODO we yield gpio_lock here because |
792 | * gpiochip_sysfs_register() acquires a mutex. This is unsafe | |
793 | * and needs to be fixed. | |
14141a93 AC |
794 | * |
795 | * Also it would be nice to use gpiochip_find() here so we | |
796 | * can keep gpio_chips local to gpiolib.c, but the yield of | |
797 | * gpio_lock prevents us from doing this. | |
798 | */ | |
0eb4c6c2 | 799 | spin_unlock_irqrestore(&gpio_lock, flags); |
426577bd | 800 | status = gpiochip_sysfs_register(chip); |
0eb4c6c2 AC |
801 | spin_lock_irqsave(&gpio_lock, flags); |
802 | } | |
803 | spin_unlock_irqrestore(&gpio_lock, flags); | |
804 | ||
805 | ||
806 | return status; | |
807 | } | |
808 | postcore_initcall(gpiolib_sysfs_init); |