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