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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 | ||
cef1717b JH |
13 | #define GPIO_IRQF_TRIGGER_FALLING BIT(0) |
14 | #define GPIO_IRQF_TRIGGER_RISING BIT(1) | |
15 | #define GPIO_IRQF_TRIGGER_BOTH (GPIO_IRQF_TRIGGER_FALLING | \ | |
16 | GPIO_IRQF_TRIGGER_RISING) | |
17 | ||
c43960fb JH |
18 | struct gpiod_data { |
19 | struct gpio_desc *desc; | |
6ffcb797 JH |
20 | |
21 | struct mutex mutex; | |
a08f5c21 | 22 | struct kernfs_node *value_kn; |
2ec74a95 | 23 | int irq; |
cef1717b | 24 | unsigned char irq_flags; |
427fdeef JH |
25 | |
26 | bool direction_can_change; | |
c43960fb JH |
27 | }; |
28 | ||
6ffcb797 JH |
29 | /* |
30 | * Lock to serialise gpiod export and unexport, and prevent re-export of | |
31 | * gpiod whose chip is being unregistered. | |
0eb4c6c2 AC |
32 | */ |
33 | static DEFINE_MUTEX(sysfs_lock); | |
34 | ||
35 | /* | |
36 | * /sys/class/gpio/gpioN... only for GPIOs that are exported | |
37 | * /direction | |
38 | * * MAY BE OMITTED if kernel won't allow direction changes | |
39 | * * is read/write as "in" or "out" | |
40 | * * may also be written as "high" or "low", initializing | |
41 | * output value as specified ("out" implies "low") | |
42 | * /value | |
43 | * * always readable, subject to hardware behavior | |
44 | * * may be writable, as zero/nonzero | |
45 | * /edge | |
46 | * * configures behavior of poll(2) on /value | |
47 | * * available only if pin can generate IRQs on input | |
48 | * * is read/write as "none", "falling", "rising", or "both" | |
49 | * /active_low | |
50 | * * configures polarity of /value | |
51 | * * is read/write as zero/nonzero | |
52 | * * also affects existing and subsequent "falling" and "rising" | |
53 | * /edge configuration | |
54 | */ | |
55 | ||
6beac9d1 | 56 | static ssize_t direction_show(struct device *dev, |
0eb4c6c2 AC |
57 | struct device_attribute *attr, char *buf) |
58 | { | |
c43960fb JH |
59 | struct gpiod_data *data = dev_get_drvdata(dev); |
60 | struct gpio_desc *desc = data->desc; | |
0eb4c6c2 AC |
61 | ssize_t status; |
62 | ||
6ffcb797 | 63 | mutex_lock(&data->mutex); |
0eb4c6c2 | 64 | |
f0b7866a JH |
65 | gpiod_get_direction(desc); |
66 | status = sprintf(buf, "%s\n", | |
0eb4c6c2 AC |
67 | test_bit(FLAG_IS_OUT, &desc->flags) |
68 | ? "out" : "in"); | |
0eb4c6c2 | 69 | |
6ffcb797 JH |
70 | mutex_unlock(&data->mutex); |
71 | ||
0eb4c6c2 AC |
72 | return status; |
73 | } | |
74 | ||
6beac9d1 | 75 | static ssize_t direction_store(struct device *dev, |
0eb4c6c2 AC |
76 | struct device_attribute *attr, const char *buf, size_t size) |
77 | { | |
c43960fb JH |
78 | struct gpiod_data *data = dev_get_drvdata(dev); |
79 | struct gpio_desc *desc = data->desc; | |
0eb4c6c2 AC |
80 | ssize_t status; |
81 | ||
6ffcb797 | 82 | mutex_lock(&data->mutex); |
0eb4c6c2 | 83 | |
f0b7866a | 84 | if (sysfs_streq(buf, "high")) |
0eb4c6c2 AC |
85 | status = gpiod_direction_output_raw(desc, 1); |
86 | else if (sysfs_streq(buf, "out") || sysfs_streq(buf, "low")) | |
87 | status = gpiod_direction_output_raw(desc, 0); | |
88 | else if (sysfs_streq(buf, "in")) | |
89 | status = gpiod_direction_input(desc); | |
90 | else | |
91 | status = -EINVAL; | |
92 | ||
6ffcb797 JH |
93 | mutex_unlock(&data->mutex); |
94 | ||
0eb4c6c2 AC |
95 | return status ? : size; |
96 | } | |
6beac9d1 | 97 | static DEVICE_ATTR_RW(direction); |
0eb4c6c2 | 98 | |
6beac9d1 | 99 | static ssize_t value_show(struct device *dev, |
0eb4c6c2 AC |
100 | struct device_attribute *attr, char *buf) |
101 | { | |
c43960fb JH |
102 | struct gpiod_data *data = dev_get_drvdata(dev); |
103 | struct gpio_desc *desc = data->desc; | |
0eb4c6c2 AC |
104 | ssize_t status; |
105 | ||
6ffcb797 | 106 | mutex_lock(&data->mutex); |
0eb4c6c2 | 107 | |
f0b7866a | 108 | status = sprintf(buf, "%d\n", gpiod_get_value_cansleep(desc)); |
0eb4c6c2 | 109 | |
6ffcb797 JH |
110 | mutex_unlock(&data->mutex); |
111 | ||
0eb4c6c2 AC |
112 | return status; |
113 | } | |
114 | ||
6beac9d1 | 115 | static ssize_t value_store(struct device *dev, |
0eb4c6c2 AC |
116 | struct device_attribute *attr, const char *buf, size_t size) |
117 | { | |
c43960fb JH |
118 | struct gpiod_data *data = dev_get_drvdata(dev); |
119 | struct gpio_desc *desc = data->desc; | |
0eb4c6c2 AC |
120 | ssize_t status; |
121 | ||
6ffcb797 | 122 | mutex_lock(&data->mutex); |
0eb4c6c2 | 123 | |
f0b7866a | 124 | if (!test_bit(FLAG_IS_OUT, &desc->flags)) { |
0eb4c6c2 | 125 | status = -EPERM; |
f0b7866a | 126 | } else { |
0eb4c6c2 AC |
127 | long value; |
128 | ||
129 | status = kstrtol(buf, 0, &value); | |
130 | if (status == 0) { | |
131 | gpiod_set_value_cansleep(desc, value); | |
132 | status = size; | |
133 | } | |
134 | } | |
135 | ||
6ffcb797 JH |
136 | mutex_unlock(&data->mutex); |
137 | ||
0eb4c6c2 AC |
138 | return status; |
139 | } | |
6beac9d1 | 140 | static DEVICE_ATTR_RW(value); |
0eb4c6c2 AC |
141 | |
142 | static irqreturn_t gpio_sysfs_irq(int irq, void *priv) | |
143 | { | |
a08f5c21 JH |
144 | struct gpiod_data *data = priv; |
145 | ||
146 | sysfs_notify_dirent(data->value_kn); | |
0eb4c6c2 | 147 | |
0eb4c6c2 AC |
148 | return IRQ_HANDLED; |
149 | } | |
150 | ||
6ffcb797 | 151 | /* Caller holds gpiod-data mutex. */ |
cef1717b | 152 | static int gpio_sysfs_request_irq(struct device *dev, unsigned char flags) |
0eb4c6c2 | 153 | { |
0f628508 JH |
154 | struct gpiod_data *data = dev_get_drvdata(dev); |
155 | struct gpio_desc *desc = data->desc; | |
0eb4c6c2 | 156 | unsigned long irq_flags; |
2ec74a95 | 157 | int ret; |
0eb4c6c2 | 158 | |
2ec74a95 JH |
159 | data->irq = gpiod_to_irq(desc); |
160 | if (data->irq < 0) | |
0eb4c6c2 AC |
161 | return -EIO; |
162 | ||
2ec74a95 JH |
163 | data->value_kn = sysfs_get_dirent(dev->kobj.sd, "value"); |
164 | if (!data->value_kn) | |
165 | return -ENODEV; | |
0eb4c6c2 AC |
166 | |
167 | irq_flags = IRQF_SHARED; | |
cef1717b | 168 | if (flags & GPIO_IRQF_TRIGGER_FALLING) |
0eb4c6c2 AC |
169 | irq_flags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ? |
170 | IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING; | |
cef1717b | 171 | if (flags & GPIO_IRQF_TRIGGER_RISING) |
0eb4c6c2 AC |
172 | irq_flags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ? |
173 | IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING; | |
174 | ||
52176d0d JH |
175 | /* |
176 | * FIXME: This should be done in the irq_request_resources callback | |
177 | * when the irq is requested, but a few drivers currently fail | |
178 | * to do so. | |
179 | * | |
180 | * Remove this redundant call (along with the corresponding | |
181 | * unlock) when those drivers have been fixed. | |
182 | */ | |
fdeb8e15 | 183 | ret = gpiochip_lock_as_irq(desc->gdev->chip, gpio_chip_hwgpio(desc)); |
0eb4c6c2 | 184 | if (ret < 0) |
2ec74a95 | 185 | goto err_put_kn; |
0eb4c6c2 | 186 | |
2ec74a95 | 187 | ret = request_any_context_irq(data->irq, gpio_sysfs_irq, irq_flags, |
a08f5c21 | 188 | "gpiolib", data); |
52176d0d JH |
189 | if (ret < 0) |
190 | goto err_unlock; | |
0eb4c6c2 | 191 | |
cef1717b | 192 | data->irq_flags = flags; |
2ec74a95 | 193 | |
0eb4c6c2 AC |
194 | return 0; |
195 | ||
52176d0d | 196 | err_unlock: |
fdeb8e15 | 197 | gpiochip_unlock_as_irq(desc->gdev->chip, gpio_chip_hwgpio(desc)); |
2ec74a95 JH |
198 | err_put_kn: |
199 | sysfs_put(data->value_kn); | |
200 | ||
0eb4c6c2 AC |
201 | return ret; |
202 | } | |
203 | ||
6ffcb797 JH |
204 | /* |
205 | * Caller holds gpiod-data mutex (unless called after class-device | |
206 | * deregistration). | |
207 | */ | |
2ec74a95 JH |
208 | static void gpio_sysfs_free_irq(struct device *dev) |
209 | { | |
210 | struct gpiod_data *data = dev_get_drvdata(dev); | |
211 | struct gpio_desc *desc = data->desc; | |
212 | ||
cef1717b | 213 | data->irq_flags = 0; |
2ec74a95 | 214 | free_irq(data->irq, data); |
fdeb8e15 | 215 | gpiochip_unlock_as_irq(desc->gdev->chip, gpio_chip_hwgpio(desc)); |
2ec74a95 JH |
216 | sysfs_put(data->value_kn); |
217 | } | |
218 | ||
0eb4c6c2 AC |
219 | static const struct { |
220 | const char *name; | |
cef1717b | 221 | unsigned char flags; |
0eb4c6c2 AC |
222 | } trigger_types[] = { |
223 | { "none", 0 }, | |
cef1717b JH |
224 | { "falling", GPIO_IRQF_TRIGGER_FALLING }, |
225 | { "rising", GPIO_IRQF_TRIGGER_RISING }, | |
226 | { "both", GPIO_IRQF_TRIGGER_BOTH }, | |
0eb4c6c2 AC |
227 | }; |
228 | ||
6beac9d1 | 229 | static ssize_t edge_show(struct device *dev, |
0eb4c6c2 AC |
230 | struct device_attribute *attr, char *buf) |
231 | { | |
c43960fb | 232 | struct gpiod_data *data = dev_get_drvdata(dev); |
f0b7866a JH |
233 | ssize_t status = 0; |
234 | int i; | |
0eb4c6c2 | 235 | |
6ffcb797 | 236 | mutex_lock(&data->mutex); |
0eb4c6c2 | 237 | |
f0b7866a | 238 | for (i = 0; i < ARRAY_SIZE(trigger_types); i++) { |
cef1717b | 239 | if (data->irq_flags == trigger_types[i].flags) { |
f0b7866a JH |
240 | status = sprintf(buf, "%s\n", trigger_types[i].name); |
241 | break; | |
242 | } | |
0eb4c6c2 AC |
243 | } |
244 | ||
6ffcb797 JH |
245 | mutex_unlock(&data->mutex); |
246 | ||
0eb4c6c2 AC |
247 | return status; |
248 | } | |
249 | ||
6beac9d1 | 250 | static ssize_t edge_store(struct device *dev, |
0eb4c6c2 AC |
251 | struct device_attribute *attr, const char *buf, size_t size) |
252 | { | |
b91e1807 | 253 | struct gpiod_data *data = dev_get_drvdata(dev); |
cef1717b | 254 | unsigned char flags; |
2ec74a95 | 255 | ssize_t status = size; |
e4339ce3 | 256 | int i; |
0eb4c6c2 | 257 | |
e4339ce3 | 258 | for (i = 0; i < ARRAY_SIZE(trigger_types); i++) { |
0eb4c6c2 | 259 | if (sysfs_streq(trigger_types[i].name, buf)) |
e4339ce3 JH |
260 | break; |
261 | } | |
262 | ||
263 | if (i == ARRAY_SIZE(trigger_types)) | |
264 | return -EINVAL; | |
0eb4c6c2 | 265 | |
b91e1807 JH |
266 | flags = trigger_types[i].flags; |
267 | ||
6ffcb797 | 268 | mutex_lock(&data->mutex); |
0eb4c6c2 | 269 | |
cef1717b | 270 | if (flags == data->irq_flags) { |
b91e1807 JH |
271 | status = size; |
272 | goto out_unlock; | |
273 | } | |
274 | ||
cef1717b | 275 | if (data->irq_flags) |
2ec74a95 JH |
276 | gpio_sysfs_free_irq(dev); |
277 | ||
278 | if (flags) { | |
279 | status = gpio_sysfs_request_irq(dev, flags); | |
280 | if (!status) | |
281 | status = size; | |
282 | } | |
0eb4c6c2 | 283 | |
b91e1807 | 284 | out_unlock: |
6ffcb797 | 285 | mutex_unlock(&data->mutex); |
0eb4c6c2 AC |
286 | |
287 | return status; | |
288 | } | |
6beac9d1 | 289 | static DEVICE_ATTR_RW(edge); |
0eb4c6c2 | 290 | |
6ffcb797 | 291 | /* Caller holds gpiod-data mutex. */ |
2f323b85 | 292 | static int gpio_sysfs_set_active_low(struct device *dev, int value) |
0eb4c6c2 | 293 | { |
0f628508 JH |
294 | struct gpiod_data *data = dev_get_drvdata(dev); |
295 | struct gpio_desc *desc = data->desc; | |
0eb4c6c2 | 296 | int status = 0; |
cef1717b | 297 | unsigned int flags = data->irq_flags; |
0eb4c6c2 AC |
298 | |
299 | if (!!test_bit(FLAG_ACTIVE_LOW, &desc->flags) == !!value) | |
300 | return 0; | |
301 | ||
302 | if (value) | |
303 | set_bit(FLAG_ACTIVE_LOW, &desc->flags); | |
304 | else | |
305 | clear_bit(FLAG_ACTIVE_LOW, &desc->flags); | |
306 | ||
307 | /* reconfigure poll(2) support if enabled on one edge only */ | |
cef1717b JH |
308 | if (flags == GPIO_IRQF_TRIGGER_FALLING || |
309 | flags == GPIO_IRQF_TRIGGER_RISING) { | |
2ec74a95 | 310 | gpio_sysfs_free_irq(dev); |
cef1717b | 311 | status = gpio_sysfs_request_irq(dev, flags); |
0eb4c6c2 AC |
312 | } |
313 | ||
314 | return status; | |
315 | } | |
316 | ||
6beac9d1 | 317 | static ssize_t active_low_show(struct device *dev, |
0eb4c6c2 AC |
318 | struct device_attribute *attr, char *buf) |
319 | { | |
c43960fb JH |
320 | struct gpiod_data *data = dev_get_drvdata(dev); |
321 | struct gpio_desc *desc = data->desc; | |
0eb4c6c2 AC |
322 | ssize_t status; |
323 | ||
6ffcb797 | 324 | mutex_lock(&data->mutex); |
0eb4c6c2 | 325 | |
f0b7866a | 326 | status = sprintf(buf, "%d\n", |
0eb4c6c2 AC |
327 | !!test_bit(FLAG_ACTIVE_LOW, &desc->flags)); |
328 | ||
6ffcb797 | 329 | mutex_unlock(&data->mutex); |
0eb4c6c2 AC |
330 | |
331 | return status; | |
332 | } | |
333 | ||
6beac9d1 | 334 | static ssize_t active_low_store(struct device *dev, |
0eb4c6c2 AC |
335 | struct device_attribute *attr, const char *buf, size_t size) |
336 | { | |
6ffcb797 | 337 | struct gpiod_data *data = dev_get_drvdata(dev); |
0eb4c6c2 | 338 | ssize_t status; |
f0b7866a | 339 | long value; |
0eb4c6c2 | 340 | |
6ffcb797 | 341 | mutex_lock(&data->mutex); |
0eb4c6c2 | 342 | |
f0b7866a JH |
343 | status = kstrtol(buf, 0, &value); |
344 | if (status == 0) | |
2f323b85 | 345 | status = gpio_sysfs_set_active_low(dev, value); |
0eb4c6c2 | 346 | |
6ffcb797 | 347 | mutex_unlock(&data->mutex); |
0eb4c6c2 AC |
348 | |
349 | return status ? : size; | |
350 | } | |
6beac9d1 | 351 | static DEVICE_ATTR_RW(active_low); |
0eb4c6c2 | 352 | |
ebbeba12 JH |
353 | static umode_t gpio_is_visible(struct kobject *kobj, struct attribute *attr, |
354 | int n) | |
355 | { | |
356 | struct device *dev = container_of(kobj, struct device, kobj); | |
c43960fb JH |
357 | struct gpiod_data *data = dev_get_drvdata(dev); |
358 | struct gpio_desc *desc = data->desc; | |
ebbeba12 | 359 | umode_t mode = attr->mode; |
427fdeef | 360 | bool show_direction = data->direction_can_change; |
ebbeba12 JH |
361 | |
362 | if (attr == &dev_attr_direction.attr) { | |
363 | if (!show_direction) | |
364 | mode = 0; | |
365 | } else if (attr == &dev_attr_edge.attr) { | |
366 | if (gpiod_to_irq(desc) < 0) | |
367 | mode = 0; | |
368 | if (!show_direction && test_bit(FLAG_IS_OUT, &desc->flags)) | |
369 | mode = 0; | |
370 | } | |
371 | ||
372 | return mode; | |
373 | } | |
374 | ||
0915e6fe | 375 | static struct attribute *gpio_attrs[] = { |
ebbeba12 JH |
376 | &dev_attr_direction.attr, |
377 | &dev_attr_edge.attr, | |
0eb4c6c2 AC |
378 | &dev_attr_value.attr, |
379 | &dev_attr_active_low.attr, | |
380 | NULL, | |
381 | }; | |
ebbeba12 JH |
382 | |
383 | static const struct attribute_group gpio_group = { | |
384 | .attrs = gpio_attrs, | |
385 | .is_visible = gpio_is_visible, | |
386 | }; | |
387 | ||
388 | static const struct attribute_group *gpio_groups[] = { | |
389 | &gpio_group, | |
390 | NULL | |
391 | }; | |
0eb4c6c2 AC |
392 | |
393 | /* | |
394 | * /sys/class/gpio/gpiochipN/ | |
395 | * /base ... matching gpio_chip.base (N) | |
396 | * /label ... matching gpio_chip.label | |
397 | * /ngpio ... matching gpio_chip.ngpio | |
398 | */ | |
399 | ||
6beac9d1 | 400 | static ssize_t base_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, "%d\n", chip->base); | |
406 | } | |
6beac9d1 | 407 | static DEVICE_ATTR_RO(base); |
0eb4c6c2 | 408 | |
6beac9d1 | 409 | static ssize_t label_show(struct device *dev, |
0eb4c6c2 AC |
410 | struct device_attribute *attr, char *buf) |
411 | { | |
412 | const struct gpio_chip *chip = dev_get_drvdata(dev); | |
413 | ||
414 | return sprintf(buf, "%s\n", chip->label ? : ""); | |
415 | } | |
6beac9d1 | 416 | static DEVICE_ATTR_RO(label); |
0eb4c6c2 | 417 | |
6beac9d1 | 418 | static ssize_t ngpio_show(struct device *dev, |
0eb4c6c2 AC |
419 | struct device_attribute *attr, char *buf) |
420 | { | |
421 | const struct gpio_chip *chip = dev_get_drvdata(dev); | |
422 | ||
423 | return sprintf(buf, "%u\n", chip->ngpio); | |
424 | } | |
6beac9d1 | 425 | static DEVICE_ATTR_RO(ngpio); |
0eb4c6c2 | 426 | |
121b6a79 | 427 | static struct attribute *gpiochip_attrs[] = { |
0eb4c6c2 AC |
428 | &dev_attr_base.attr, |
429 | &dev_attr_label.attr, | |
430 | &dev_attr_ngpio.attr, | |
431 | NULL, | |
432 | }; | |
121b6a79 | 433 | ATTRIBUTE_GROUPS(gpiochip); |
0eb4c6c2 AC |
434 | |
435 | /* | |
436 | * /sys/class/gpio/export ... write-only | |
437 | * integer N ... number of GPIO to export (full access) | |
438 | * /sys/class/gpio/unexport ... write-only | |
439 | * integer N ... number of GPIO to unexport | |
440 | */ | |
441 | static ssize_t export_store(struct class *class, | |
442 | struct class_attribute *attr, | |
443 | const char *buf, size_t len) | |
444 | { | |
445 | long gpio; | |
446 | struct gpio_desc *desc; | |
447 | int status; | |
448 | ||
449 | status = kstrtol(buf, 0, &gpio); | |
450 | if (status < 0) | |
451 | goto done; | |
452 | ||
453 | desc = gpio_to_desc(gpio); | |
454 | /* reject invalid GPIOs */ | |
455 | if (!desc) { | |
456 | pr_warn("%s: invalid GPIO %ld\n", __func__, gpio); | |
457 | return -EINVAL; | |
458 | } | |
459 | ||
460 | /* No extra locking here; FLAG_SYSFS just signifies that the | |
461 | * request and export were done by on behalf of userspace, so | |
462 | * they may be undone on its behalf too. | |
463 | */ | |
464 | ||
465 | status = gpiod_request(desc, "sysfs"); | |
466 | if (status < 0) { | |
467 | if (status == -EPROBE_DEFER) | |
468 | status = -ENODEV; | |
469 | goto done; | |
470 | } | |
471 | status = gpiod_export(desc, true); | |
472 | if (status < 0) | |
473 | gpiod_free(desc); | |
474 | else | |
475 | set_bit(FLAG_SYSFS, &desc->flags); | |
476 | ||
477 | done: | |
478 | if (status) | |
479 | pr_debug("%s: status %d\n", __func__, status); | |
480 | return status ? : len; | |
481 | } | |
d83bb159 | 482 | static CLASS_ATTR_WO(export); |
0eb4c6c2 AC |
483 | |
484 | static ssize_t unexport_store(struct class *class, | |
485 | struct class_attribute *attr, | |
486 | const char *buf, size_t len) | |
487 | { | |
488 | long gpio; | |
489 | struct gpio_desc *desc; | |
490 | int status; | |
491 | ||
492 | status = kstrtol(buf, 0, &gpio); | |
493 | if (status < 0) | |
494 | goto done; | |
495 | ||
496 | desc = gpio_to_desc(gpio); | |
497 | /* reject bogus commands (gpio_unexport ignores them) */ | |
498 | if (!desc) { | |
499 | pr_warn("%s: invalid GPIO %ld\n", __func__, gpio); | |
500 | return -EINVAL; | |
501 | } | |
502 | ||
503 | status = -EINVAL; | |
504 | ||
505 | /* No extra locking here; FLAG_SYSFS just signifies that the | |
506 | * request and export were done by on behalf of userspace, so | |
507 | * they may be undone on its behalf too. | |
508 | */ | |
509 | if (test_and_clear_bit(FLAG_SYSFS, &desc->flags)) { | |
510 | status = 0; | |
511 | gpiod_free(desc); | |
512 | } | |
513 | done: | |
514 | if (status) | |
515 | pr_debug("%s: status %d\n", __func__, status); | |
516 | return status ? : len; | |
517 | } | |
d83bb159 | 518 | static CLASS_ATTR_WO(unexport); |
0eb4c6c2 | 519 | |
d83bb159 GKH |
520 | static struct attribute *gpio_class_attrs[] = { |
521 | &class_attr_export.attr, | |
522 | &class_attr_unexport.attr, | |
523 | NULL, | |
0eb4c6c2 | 524 | }; |
d83bb159 | 525 | ATTRIBUTE_GROUPS(gpio_class); |
0eb4c6c2 AC |
526 | |
527 | static struct class gpio_class = { | |
528 | .name = "gpio", | |
529 | .owner = THIS_MODULE, | |
530 | ||
d83bb159 | 531 | .class_groups = gpio_class_groups, |
0eb4c6c2 AC |
532 | }; |
533 | ||
534 | ||
535 | /** | |
536 | * gpiod_export - export a GPIO through sysfs | |
537 | * @gpio: gpio to make available, already requested | |
538 | * @direction_may_change: true if userspace may change gpio direction | |
539 | * Context: arch_initcall or later | |
540 | * | |
541 | * When drivers want to make a GPIO accessible to userspace after they | |
542 | * have requested it -- perhaps while debugging, or as part of their | |
543 | * public interface -- they may use this routine. If the GPIO can | |
544 | * change direction (some can't) and the caller allows it, userspace | |
545 | * will see "direction" sysfs attribute which may be used to change | |
546 | * the gpio's direction. A "value" attribute will always be provided. | |
547 | * | |
548 | * Returns zero on success, else an error. | |
549 | */ | |
550 | int gpiod_export(struct gpio_desc *desc, bool direction_may_change) | |
551 | { | |
483d8211 | 552 | struct gpio_chip *chip; |
ff2b1359 | 553 | struct gpio_device *gdev; |
c43960fb | 554 | struct gpiod_data *data; |
0eb4c6c2 AC |
555 | unsigned long flags; |
556 | int status; | |
557 | const char *ioname = NULL; | |
558 | struct device *dev; | |
559 | int offset; | |
560 | ||
561 | /* can't export until sysfs is available ... */ | |
562 | if (!gpio_class.p) { | |
563 | pr_debug("%s: called too early!\n", __func__); | |
564 | return -ENOENT; | |
565 | } | |
566 | ||
567 | if (!desc) { | |
568 | pr_debug("%s: invalid gpio descriptor\n", __func__); | |
569 | return -EINVAL; | |
570 | } | |
571 | ||
fdeb8e15 LW |
572 | gdev = desc->gdev; |
573 | chip = gdev->chip; | |
483d8211 | 574 | |
0eb4c6c2 AC |
575 | mutex_lock(&sysfs_lock); |
576 | ||
483d8211 | 577 | /* check if chip is being removed */ |
afbc4f31 | 578 | if (!chip || !gdev->mockdev) { |
483d8211 | 579 | status = -ENODEV; |
c43960fb | 580 | goto err_unlock; |
483d8211 JH |
581 | } |
582 | ||
0eb4c6c2 AC |
583 | spin_lock_irqsave(&gpio_lock, flags); |
584 | if (!test_bit(FLAG_REQUESTED, &desc->flags) || | |
585 | test_bit(FLAG_EXPORT, &desc->flags)) { | |
586 | spin_unlock_irqrestore(&gpio_lock, flags); | |
587 | gpiod_dbg(desc, "%s: unavailable (requested=%d, exported=%d)\n", | |
588 | __func__, | |
589 | test_bit(FLAG_REQUESTED, &desc->flags), | |
590 | test_bit(FLAG_EXPORT, &desc->flags)); | |
591 | status = -EPERM; | |
c43960fb | 592 | goto err_unlock; |
0eb4c6c2 | 593 | } |
0eb4c6c2 AC |
594 | spin_unlock_irqrestore(&gpio_lock, flags); |
595 | ||
c43960fb JH |
596 | data = kzalloc(sizeof(*data), GFP_KERNEL); |
597 | if (!data) { | |
598 | status = -ENOMEM; | |
599 | goto err_unlock; | |
600 | } | |
601 | ||
602 | data->desc = desc; | |
6ffcb797 | 603 | mutex_init(&data->mutex); |
427fdeef JH |
604 | if (chip->direction_input && chip->direction_output) |
605 | data->direction_can_change = direction_may_change; | |
606 | else | |
607 | data->direction_can_change = false; | |
c43960fb | 608 | |
0eb4c6c2 | 609 | offset = gpio_chip_hwgpio(desc); |
cecf58ab JH |
610 | if (chip->names && chip->names[offset]) |
611 | ioname = chip->names[offset]; | |
0eb4c6c2 | 612 | |
ff2b1359 | 613 | dev = device_create_with_groups(&gpio_class, &gdev->dev, |
c43960fb | 614 | MKDEV(0, 0), data, gpio_groups, |
0915e6fe JH |
615 | ioname ? ioname : "gpio%u", |
616 | desc_to_gpio(desc)); | |
0eb4c6c2 AC |
617 | if (IS_ERR(dev)) { |
618 | status = PTR_ERR(dev); | |
c43960fb | 619 | goto err_free_data; |
0eb4c6c2 AC |
620 | } |
621 | ||
0eb4c6c2 AC |
622 | set_bit(FLAG_EXPORT, &desc->flags); |
623 | mutex_unlock(&sysfs_lock); | |
624 | return 0; | |
625 | ||
c43960fb JH |
626 | err_free_data: |
627 | kfree(data); | |
628 | err_unlock: | |
0eb4c6c2 AC |
629 | mutex_unlock(&sysfs_lock); |
630 | gpiod_dbg(desc, "%s: status %d\n", __func__, status); | |
631 | return status; | |
632 | } | |
633 | EXPORT_SYMBOL_GPL(gpiod_export); | |
634 | ||
c43960fb | 635 | static int match_export(struct device *dev, const void *desc) |
0eb4c6c2 | 636 | { |
c43960fb JH |
637 | struct gpiod_data *data = dev_get_drvdata(dev); |
638 | ||
639 | return data->desc == desc; | |
0eb4c6c2 AC |
640 | } |
641 | ||
642 | /** | |
643 | * gpiod_export_link - create a sysfs link to an exported GPIO node | |
644 | * @dev: device under which to create symlink | |
645 | * @name: name of the symlink | |
646 | * @gpio: gpio to create symlink to, already exported | |
647 | * | |
648 | * Set up a symlink from /sys/.../dev/name to /sys/class/gpio/gpioN | |
649 | * node. Caller is responsible for unlinking. | |
650 | * | |
651 | * Returns zero on success, else an error. | |
652 | */ | |
653 | int gpiod_export_link(struct device *dev, const char *name, | |
654 | struct gpio_desc *desc) | |
655 | { | |
56d30ec1 JH |
656 | struct device *cdev; |
657 | int ret; | |
0eb4c6c2 AC |
658 | |
659 | if (!desc) { | |
660 | pr_warn("%s: invalid GPIO\n", __func__); | |
661 | return -EINVAL; | |
662 | } | |
663 | ||
56d30ec1 JH |
664 | cdev = class_find_device(&gpio_class, NULL, desc, match_export); |
665 | if (!cdev) | |
666 | return -ENODEV; | |
0eb4c6c2 | 667 | |
56d30ec1 JH |
668 | ret = sysfs_create_link(&dev->kobj, &cdev->kobj, name); |
669 | put_device(cdev); | |
0eb4c6c2 | 670 | |
56d30ec1 | 671 | return ret; |
0eb4c6c2 AC |
672 | } |
673 | EXPORT_SYMBOL_GPL(gpiod_export_link); | |
674 | ||
0eb4c6c2 | 675 | /** |
31963eb0 | 676 | * gpiod_unexport - reverse effect of gpiod_export() |
0eb4c6c2 AC |
677 | * @gpio: gpio to make unavailable |
678 | * | |
31963eb0 | 679 | * This is implicit on gpiod_free(). |
0eb4c6c2 AC |
680 | */ |
681 | void gpiod_unexport(struct gpio_desc *desc) | |
682 | { | |
72eba6f6 JH |
683 | struct gpiod_data *data; |
684 | struct device *dev; | |
0eb4c6c2 AC |
685 | |
686 | if (!desc) { | |
687 | pr_warn("%s: invalid GPIO\n", __func__); | |
688 | return; | |
689 | } | |
690 | ||
691 | mutex_lock(&sysfs_lock); | |
692 | ||
72eba6f6 JH |
693 | if (!test_bit(FLAG_EXPORT, &desc->flags)) |
694 | goto err_unlock; | |
0eb4c6c2 | 695 | |
72eba6f6 JH |
696 | dev = class_find_device(&gpio_class, NULL, desc, match_export); |
697 | if (!dev) | |
698 | goto err_unlock; | |
699 | ||
700 | data = dev_get_drvdata(dev); | |
701 | ||
72eba6f6 JH |
702 | clear_bit(FLAG_EXPORT, &desc->flags); |
703 | ||
704 | device_unregister(dev); | |
705 | ||
706 | /* | |
707 | * Release irq after deregistration to prevent race with edge_store. | |
708 | */ | |
cef1717b | 709 | if (data->irq_flags) |
72eba6f6 | 710 | gpio_sysfs_free_irq(dev); |
0eb4c6c2 AC |
711 | |
712 | mutex_unlock(&sysfs_lock); | |
713 | ||
72eba6f6 JH |
714 | put_device(dev); |
715 | kfree(data); | |
0eb4c6c2 | 716 | |
72eba6f6 JH |
717 | return; |
718 | ||
719 | err_unlock: | |
720 | mutex_unlock(&sysfs_lock); | |
0eb4c6c2 AC |
721 | } |
722 | EXPORT_SYMBOL_GPL(gpiod_unexport); | |
723 | ||
afbc4f31 | 724 | int gpiochip_sysfs_register(struct gpio_device *gdev) |
0eb4c6c2 | 725 | { |
0eb4c6c2 | 726 | struct device *dev; |
d27c1728 | 727 | struct device *parent; |
afbc4f31 | 728 | struct gpio_chip *chip = gdev->chip; |
0eb4c6c2 | 729 | |
426577bd JH |
730 | /* |
731 | * Many systems add gpio chips for SOC support very early, | |
0eb4c6c2 | 732 | * before driver model support is available. In those cases we |
426577bd | 733 | * register later, in gpiolib_sysfs_init() ... here we just |
0eb4c6c2 AC |
734 | * verify that _some_ field of gpio_class got initialized. |
735 | */ | |
736 | if (!gpio_class.p) | |
737 | return 0; | |
738 | ||
d27c1728 BJZ |
739 | /* |
740 | * For sysfs backward compatibility we need to preserve this | |
741 | * preferred parenting to the gpio_chip parent field, if set. | |
742 | */ | |
743 | if (chip->parent) | |
744 | parent = chip->parent; | |
745 | else | |
746 | parent = &gdev->dev; | |
747 | ||
0eb4c6c2 | 748 | /* use chip->base for the ID; it's already known to be unique */ |
d27c1728 | 749 | dev = device_create_with_groups(&gpio_class, parent, |
58383c78 | 750 | MKDEV(0, 0), |
121b6a79 JH |
751 | chip, gpiochip_groups, |
752 | "gpiochip%d", chip->base); | |
753 | if (IS_ERR(dev)) | |
6a4b6b0a | 754 | return PTR_ERR(dev); |
3ff74be5 JH |
755 | |
756 | mutex_lock(&sysfs_lock); | |
afbc4f31 | 757 | gdev->mockdev = dev; |
0eb4c6c2 AC |
758 | mutex_unlock(&sysfs_lock); |
759 | ||
6a4b6b0a | 760 | return 0; |
0eb4c6c2 AC |
761 | } |
762 | ||
afbc4f31 | 763 | void gpiochip_sysfs_unregister(struct gpio_device *gdev) |
0eb4c6c2 | 764 | { |
483d8211 | 765 | struct gpio_desc *desc; |
afbc4f31 | 766 | struct gpio_chip *chip = gdev->chip; |
483d8211 | 767 | unsigned int i; |
0eb4c6c2 | 768 | |
afbc4f31 | 769 | if (!gdev->mockdev) |
6a4b6b0a | 770 | return; |
0eb4c6c2 | 771 | |
afbc4f31 | 772 | device_unregister(gdev->mockdev); |
6a4b6b0a JH |
773 | |
774 | /* prevent further gpiod exports */ | |
775 | mutex_lock(&sysfs_lock); | |
afbc4f31 | 776 | gdev->mockdev = NULL; |
6a4b6b0a | 777 | mutex_unlock(&sysfs_lock); |
483d8211 JH |
778 | |
779 | /* unregister gpiod class devices owned by sysfs */ | |
780 | for (i = 0; i < chip->ngpio; i++) { | |
fdeb8e15 | 781 | desc = &gdev->descs[i]; |
483d8211 JH |
782 | if (test_and_clear_bit(FLAG_SYSFS, &desc->flags)) |
783 | gpiod_free(desc); | |
784 | } | |
0eb4c6c2 AC |
785 | } |
786 | ||
787 | static int __init gpiolib_sysfs_init(void) | |
788 | { | |
789 | int status; | |
790 | unsigned long flags; | |
ff2b1359 | 791 | struct gpio_device *gdev; |
0eb4c6c2 AC |
792 | |
793 | status = class_register(&gpio_class); | |
794 | if (status < 0) | |
795 | return status; | |
796 | ||
797 | /* Scan and register the gpio_chips which registered very | |
798 | * early (e.g. before the class_register above was called). | |
799 | * | |
800 | * We run before arch_initcall() so chip->dev nodes can have | |
801 | * registered, and so arch_initcall() can always gpio_export(). | |
802 | */ | |
803 | spin_lock_irqsave(&gpio_lock, flags); | |
ff2b1359 | 804 | list_for_each_entry(gdev, &gpio_devices, list) { |
afbc4f31 | 805 | if (gdev->mockdev) |
0eb4c6c2 AC |
806 | continue; |
807 | ||
14141a93 | 808 | /* |
426577bd JH |
809 | * TODO we yield gpio_lock here because |
810 | * gpiochip_sysfs_register() acquires a mutex. This is unsafe | |
811 | * and needs to be fixed. | |
14141a93 AC |
812 | * |
813 | * Also it would be nice to use gpiochip_find() here so we | |
814 | * can keep gpio_chips local to gpiolib.c, but the yield of | |
815 | * gpio_lock prevents us from doing this. | |
816 | */ | |
0eb4c6c2 | 817 | spin_unlock_irqrestore(&gpio_lock, flags); |
afbc4f31 | 818 | status = gpiochip_sysfs_register(gdev); |
0eb4c6c2 AC |
819 | spin_lock_irqsave(&gpio_lock, flags); |
820 | } | |
821 | spin_unlock_irqrestore(&gpio_lock, flags); | |
822 | ||
0eb4c6c2 AC |
823 | return status; |
824 | } | |
825 | postcore_initcall(gpiolib_sysfs_init); |