Commit | Line | Data |
---|---|---|
0eb4c6c2 AC |
1 | #include <linux/idr.h> |
2 | #include <linux/mutex.h> | |
3 | #include <linux/device.h> | |
4 | #include <linux/sysfs.h> | |
90b05b05 | 5 | #include <linux/gpio.h> |
0eb4c6c2 AC |
6 | #include <linux/gpio/consumer.h> |
7 | #include <linux/gpio/driver.h> | |
8 | #include <linux/interrupt.h> | |
9 | #include <linux/kdev_t.h> | |
c43960fb | 10 | #include <linux/slab.h> |
0eb4c6c2 AC |
11 | |
12 | #include "gpiolib.h" | |
13 | ||
cef1717b JH |
14 | #define GPIO_IRQF_TRIGGER_FALLING BIT(0) |
15 | #define GPIO_IRQF_TRIGGER_RISING BIT(1) | |
16 | #define GPIO_IRQF_TRIGGER_BOTH (GPIO_IRQF_TRIGGER_FALLING | \ | |
17 | GPIO_IRQF_TRIGGER_RISING) | |
18 | ||
c43960fb JH |
19 | struct gpiod_data { |
20 | struct gpio_desc *desc; | |
6ffcb797 JH |
21 | |
22 | struct mutex mutex; | |
a08f5c21 | 23 | struct kernfs_node *value_kn; |
2ec74a95 | 24 | int irq; |
cef1717b | 25 | unsigned char irq_flags; |
427fdeef JH |
26 | |
27 | bool direction_can_change; | |
c43960fb JH |
28 | }; |
29 | ||
6ffcb797 JH |
30 | /* |
31 | * Lock to serialise gpiod export and unexport, and prevent re-export of | |
32 | * gpiod whose chip is being unregistered. | |
0eb4c6c2 AC |
33 | */ |
34 | static DEFINE_MUTEX(sysfs_lock); | |
35 | ||
36 | /* | |
37 | * /sys/class/gpio/gpioN... only for GPIOs that are exported | |
38 | * /direction | |
39 | * * MAY BE OMITTED if kernel won't allow direction changes | |
40 | * * is read/write as "in" or "out" | |
41 | * * may also be written as "high" or "low", initializing | |
42 | * output value as specified ("out" implies "low") | |
43 | * /value | |
44 | * * always readable, subject to hardware behavior | |
45 | * * may be writable, as zero/nonzero | |
46 | * /edge | |
47 | * * configures behavior of poll(2) on /value | |
48 | * * available only if pin can generate IRQs on input | |
49 | * * is read/write as "none", "falling", "rising", or "both" | |
50 | * /active_low | |
51 | * * configures polarity of /value | |
52 | * * is read/write as zero/nonzero | |
53 | * * also affects existing and subsequent "falling" and "rising" | |
54 | * /edge configuration | |
55 | */ | |
56 | ||
6beac9d1 | 57 | static ssize_t direction_show(struct device *dev, |
0eb4c6c2 AC |
58 | struct device_attribute *attr, char *buf) |
59 | { | |
c43960fb JH |
60 | struct gpiod_data *data = dev_get_drvdata(dev); |
61 | struct gpio_desc *desc = data->desc; | |
0eb4c6c2 AC |
62 | ssize_t status; |
63 | ||
6ffcb797 | 64 | mutex_lock(&data->mutex); |
0eb4c6c2 | 65 | |
f0b7866a JH |
66 | gpiod_get_direction(desc); |
67 | status = sprintf(buf, "%s\n", | |
0eb4c6c2 AC |
68 | test_bit(FLAG_IS_OUT, &desc->flags) |
69 | ? "out" : "in"); | |
0eb4c6c2 | 70 | |
6ffcb797 JH |
71 | mutex_unlock(&data->mutex); |
72 | ||
0eb4c6c2 AC |
73 | return status; |
74 | } | |
75 | ||
6beac9d1 | 76 | static ssize_t direction_store(struct device *dev, |
0eb4c6c2 AC |
77 | struct device_attribute *attr, const char *buf, size_t size) |
78 | { | |
c43960fb JH |
79 | struct gpiod_data *data = dev_get_drvdata(dev); |
80 | struct gpio_desc *desc = data->desc; | |
0eb4c6c2 AC |
81 | ssize_t status; |
82 | ||
6ffcb797 | 83 | mutex_lock(&data->mutex); |
0eb4c6c2 | 84 | |
f0b7866a | 85 | if (sysfs_streq(buf, "high")) |
0eb4c6c2 AC |
86 | status = gpiod_direction_output_raw(desc, 1); |
87 | else if (sysfs_streq(buf, "out") || sysfs_streq(buf, "low")) | |
88 | status = gpiod_direction_output_raw(desc, 0); | |
89 | else if (sysfs_streq(buf, "in")) | |
90 | status = gpiod_direction_input(desc); | |
91 | else | |
92 | status = -EINVAL; | |
93 | ||
6ffcb797 JH |
94 | mutex_unlock(&data->mutex); |
95 | ||
0eb4c6c2 AC |
96 | return status ? : size; |
97 | } | |
6beac9d1 | 98 | static DEVICE_ATTR_RW(direction); |
0eb4c6c2 | 99 | |
6beac9d1 | 100 | static ssize_t value_show(struct device *dev, |
0eb4c6c2 AC |
101 | struct device_attribute *attr, char *buf) |
102 | { | |
c43960fb JH |
103 | struct gpiod_data *data = dev_get_drvdata(dev); |
104 | struct gpio_desc *desc = data->desc; | |
0eb4c6c2 AC |
105 | ssize_t status; |
106 | ||
6ffcb797 | 107 | mutex_lock(&data->mutex); |
0eb4c6c2 | 108 | |
f0b7866a | 109 | status = sprintf(buf, "%d\n", gpiod_get_value_cansleep(desc)); |
0eb4c6c2 | 110 | |
6ffcb797 JH |
111 | mutex_unlock(&data->mutex); |
112 | ||
0eb4c6c2 AC |
113 | return status; |
114 | } | |
115 | ||
6beac9d1 | 116 | static ssize_t value_store(struct device *dev, |
0eb4c6c2 AC |
117 | struct device_attribute *attr, const char *buf, size_t size) |
118 | { | |
c43960fb JH |
119 | struct gpiod_data *data = dev_get_drvdata(dev); |
120 | struct gpio_desc *desc = data->desc; | |
0eb4c6c2 AC |
121 | ssize_t status; |
122 | ||
6ffcb797 | 123 | mutex_lock(&data->mutex); |
0eb4c6c2 | 124 | |
f0b7866a | 125 | if (!test_bit(FLAG_IS_OUT, &desc->flags)) { |
0eb4c6c2 | 126 | status = -EPERM; |
f0b7866a | 127 | } else { |
0eb4c6c2 AC |
128 | long value; |
129 | ||
130 | status = kstrtol(buf, 0, &value); | |
131 | if (status == 0) { | |
132 | gpiod_set_value_cansleep(desc, value); | |
133 | status = size; | |
134 | } | |
135 | } | |
136 | ||
6ffcb797 JH |
137 | mutex_unlock(&data->mutex); |
138 | ||
0eb4c6c2 AC |
139 | return status; |
140 | } | |
6beac9d1 | 141 | static DEVICE_ATTR_RW(value); |
0eb4c6c2 AC |
142 | |
143 | static irqreturn_t gpio_sysfs_irq(int irq, void *priv) | |
144 | { | |
a08f5c21 JH |
145 | struct gpiod_data *data = priv; |
146 | ||
147 | sysfs_notify_dirent(data->value_kn); | |
0eb4c6c2 | 148 | |
0eb4c6c2 AC |
149 | return IRQ_HANDLED; |
150 | } | |
151 | ||
6ffcb797 | 152 | /* Caller holds gpiod-data mutex. */ |
cef1717b | 153 | static int gpio_sysfs_request_irq(struct device *dev, unsigned char flags) |
0eb4c6c2 | 154 | { |
0f628508 JH |
155 | struct gpiod_data *data = dev_get_drvdata(dev); |
156 | struct gpio_desc *desc = data->desc; | |
0eb4c6c2 | 157 | unsigned long irq_flags; |
2ec74a95 | 158 | int ret; |
0eb4c6c2 | 159 | |
2ec74a95 JH |
160 | data->irq = gpiod_to_irq(desc); |
161 | if (data->irq < 0) | |
0eb4c6c2 AC |
162 | return -EIO; |
163 | ||
2ec74a95 JH |
164 | data->value_kn = sysfs_get_dirent(dev->kobj.sd, "value"); |
165 | if (!data->value_kn) | |
166 | return -ENODEV; | |
0eb4c6c2 AC |
167 | |
168 | irq_flags = IRQF_SHARED; | |
cef1717b | 169 | if (flags & GPIO_IRQF_TRIGGER_FALLING) |
0eb4c6c2 AC |
170 | irq_flags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ? |
171 | IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING; | |
cef1717b | 172 | if (flags & GPIO_IRQF_TRIGGER_RISING) |
0eb4c6c2 AC |
173 | irq_flags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ? |
174 | IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING; | |
175 | ||
52176d0d JH |
176 | /* |
177 | * FIXME: This should be done in the irq_request_resources callback | |
178 | * when the irq is requested, but a few drivers currently fail | |
179 | * to do so. | |
180 | * | |
181 | * Remove this redundant call (along with the corresponding | |
182 | * unlock) when those drivers have been fixed. | |
183 | */ | |
fdeb8e15 | 184 | ret = gpiochip_lock_as_irq(desc->gdev->chip, gpio_chip_hwgpio(desc)); |
0eb4c6c2 | 185 | if (ret < 0) |
2ec74a95 | 186 | goto err_put_kn; |
0eb4c6c2 | 187 | |
2ec74a95 | 188 | ret = request_any_context_irq(data->irq, gpio_sysfs_irq, irq_flags, |
a08f5c21 | 189 | "gpiolib", data); |
52176d0d JH |
190 | if (ret < 0) |
191 | goto err_unlock; | |
0eb4c6c2 | 192 | |
cef1717b | 193 | data->irq_flags = flags; |
2ec74a95 | 194 | |
0eb4c6c2 AC |
195 | return 0; |
196 | ||
52176d0d | 197 | err_unlock: |
fdeb8e15 | 198 | gpiochip_unlock_as_irq(desc->gdev->chip, gpio_chip_hwgpio(desc)); |
2ec74a95 JH |
199 | err_put_kn: |
200 | sysfs_put(data->value_kn); | |
201 | ||
0eb4c6c2 AC |
202 | return ret; |
203 | } | |
204 | ||
6ffcb797 JH |
205 | /* |
206 | * Caller holds gpiod-data mutex (unless called after class-device | |
207 | * deregistration). | |
208 | */ | |
2ec74a95 JH |
209 | static void gpio_sysfs_free_irq(struct device *dev) |
210 | { | |
211 | struct gpiod_data *data = dev_get_drvdata(dev); | |
212 | struct gpio_desc *desc = data->desc; | |
213 | ||
cef1717b | 214 | data->irq_flags = 0; |
2ec74a95 | 215 | free_irq(data->irq, data); |
fdeb8e15 | 216 | gpiochip_unlock_as_irq(desc->gdev->chip, gpio_chip_hwgpio(desc)); |
2ec74a95 JH |
217 | sysfs_put(data->value_kn); |
218 | } | |
219 | ||
0eb4c6c2 AC |
220 | static const struct { |
221 | const char *name; | |
cef1717b | 222 | unsigned char flags; |
0eb4c6c2 AC |
223 | } trigger_types[] = { |
224 | { "none", 0 }, | |
cef1717b JH |
225 | { "falling", GPIO_IRQF_TRIGGER_FALLING }, |
226 | { "rising", GPIO_IRQF_TRIGGER_RISING }, | |
227 | { "both", GPIO_IRQF_TRIGGER_BOTH }, | |
0eb4c6c2 AC |
228 | }; |
229 | ||
6beac9d1 | 230 | static ssize_t edge_show(struct device *dev, |
0eb4c6c2 AC |
231 | struct device_attribute *attr, char *buf) |
232 | { | |
c43960fb | 233 | struct gpiod_data *data = dev_get_drvdata(dev); |
f0b7866a JH |
234 | ssize_t status = 0; |
235 | int i; | |
0eb4c6c2 | 236 | |
6ffcb797 | 237 | mutex_lock(&data->mutex); |
0eb4c6c2 | 238 | |
f0b7866a | 239 | for (i = 0; i < ARRAY_SIZE(trigger_types); i++) { |
cef1717b | 240 | if (data->irq_flags == trigger_types[i].flags) { |
f0b7866a JH |
241 | status = sprintf(buf, "%s\n", trigger_types[i].name); |
242 | break; | |
243 | } | |
0eb4c6c2 AC |
244 | } |
245 | ||
6ffcb797 JH |
246 | mutex_unlock(&data->mutex); |
247 | ||
0eb4c6c2 AC |
248 | return status; |
249 | } | |
250 | ||
6beac9d1 | 251 | static ssize_t edge_store(struct device *dev, |
0eb4c6c2 AC |
252 | struct device_attribute *attr, const char *buf, size_t size) |
253 | { | |
b91e1807 | 254 | struct gpiod_data *data = dev_get_drvdata(dev); |
cef1717b | 255 | unsigned char flags; |
2ec74a95 | 256 | ssize_t status = size; |
e4339ce3 | 257 | int i; |
0eb4c6c2 | 258 | |
e4339ce3 | 259 | for (i = 0; i < ARRAY_SIZE(trigger_types); i++) { |
0eb4c6c2 | 260 | if (sysfs_streq(trigger_types[i].name, buf)) |
e4339ce3 JH |
261 | break; |
262 | } | |
263 | ||
264 | if (i == ARRAY_SIZE(trigger_types)) | |
265 | return -EINVAL; | |
0eb4c6c2 | 266 | |
b91e1807 JH |
267 | flags = trigger_types[i].flags; |
268 | ||
6ffcb797 | 269 | mutex_lock(&data->mutex); |
0eb4c6c2 | 270 | |
cef1717b | 271 | if (flags == data->irq_flags) { |
b91e1807 JH |
272 | status = size; |
273 | goto out_unlock; | |
274 | } | |
275 | ||
cef1717b | 276 | if (data->irq_flags) |
2ec74a95 JH |
277 | gpio_sysfs_free_irq(dev); |
278 | ||
279 | if (flags) { | |
280 | status = gpio_sysfs_request_irq(dev, flags); | |
281 | if (!status) | |
282 | status = size; | |
283 | } | |
0eb4c6c2 | 284 | |
b91e1807 | 285 | out_unlock: |
6ffcb797 | 286 | mutex_unlock(&data->mutex); |
0eb4c6c2 AC |
287 | |
288 | return status; | |
289 | } | |
6beac9d1 | 290 | static DEVICE_ATTR_RW(edge); |
0eb4c6c2 | 291 | |
6ffcb797 | 292 | /* Caller holds gpiod-data mutex. */ |
2f323b85 | 293 | static int gpio_sysfs_set_active_low(struct device *dev, int value) |
0eb4c6c2 | 294 | { |
0f628508 JH |
295 | struct gpiod_data *data = dev_get_drvdata(dev); |
296 | struct gpio_desc *desc = data->desc; | |
0eb4c6c2 | 297 | int status = 0; |
cef1717b | 298 | unsigned int flags = data->irq_flags; |
0eb4c6c2 AC |
299 | |
300 | if (!!test_bit(FLAG_ACTIVE_LOW, &desc->flags) == !!value) | |
301 | return 0; | |
302 | ||
303 | if (value) | |
304 | set_bit(FLAG_ACTIVE_LOW, &desc->flags); | |
305 | else | |
306 | clear_bit(FLAG_ACTIVE_LOW, &desc->flags); | |
307 | ||
308 | /* reconfigure poll(2) support if enabled on one edge only */ | |
cef1717b JH |
309 | if (flags == GPIO_IRQF_TRIGGER_FALLING || |
310 | flags == GPIO_IRQF_TRIGGER_RISING) { | |
2ec74a95 | 311 | gpio_sysfs_free_irq(dev); |
cef1717b | 312 | status = gpio_sysfs_request_irq(dev, flags); |
0eb4c6c2 AC |
313 | } |
314 | ||
315 | return status; | |
316 | } | |
317 | ||
6beac9d1 | 318 | static ssize_t active_low_show(struct device *dev, |
0eb4c6c2 AC |
319 | struct device_attribute *attr, char *buf) |
320 | { | |
c43960fb JH |
321 | struct gpiod_data *data = dev_get_drvdata(dev); |
322 | struct gpio_desc *desc = data->desc; | |
0eb4c6c2 AC |
323 | ssize_t status; |
324 | ||
6ffcb797 | 325 | mutex_lock(&data->mutex); |
0eb4c6c2 | 326 | |
f0b7866a | 327 | status = sprintf(buf, "%d\n", |
0eb4c6c2 AC |
328 | !!test_bit(FLAG_ACTIVE_LOW, &desc->flags)); |
329 | ||
6ffcb797 | 330 | mutex_unlock(&data->mutex); |
0eb4c6c2 AC |
331 | |
332 | return status; | |
333 | } | |
334 | ||
6beac9d1 | 335 | static ssize_t active_low_store(struct device *dev, |
0eb4c6c2 AC |
336 | struct device_attribute *attr, const char *buf, size_t size) |
337 | { | |
6ffcb797 | 338 | struct gpiod_data *data = dev_get_drvdata(dev); |
0eb4c6c2 | 339 | ssize_t status; |
f0b7866a | 340 | long value; |
0eb4c6c2 | 341 | |
6ffcb797 | 342 | mutex_lock(&data->mutex); |
0eb4c6c2 | 343 | |
f0b7866a JH |
344 | status = kstrtol(buf, 0, &value); |
345 | if (status == 0) | |
2f323b85 | 346 | status = gpio_sysfs_set_active_low(dev, value); |
0eb4c6c2 | 347 | |
6ffcb797 | 348 | mutex_unlock(&data->mutex); |
0eb4c6c2 AC |
349 | |
350 | return status ? : size; | |
351 | } | |
6beac9d1 | 352 | static DEVICE_ATTR_RW(active_low); |
0eb4c6c2 | 353 | |
ebbeba12 JH |
354 | static umode_t gpio_is_visible(struct kobject *kobj, struct attribute *attr, |
355 | int n) | |
356 | { | |
357 | struct device *dev = container_of(kobj, struct device, kobj); | |
c43960fb JH |
358 | struct gpiod_data *data = dev_get_drvdata(dev); |
359 | struct gpio_desc *desc = data->desc; | |
ebbeba12 | 360 | umode_t mode = attr->mode; |
427fdeef | 361 | bool show_direction = data->direction_can_change; |
ebbeba12 JH |
362 | |
363 | if (attr == &dev_attr_direction.attr) { | |
364 | if (!show_direction) | |
365 | mode = 0; | |
366 | } else if (attr == &dev_attr_edge.attr) { | |
367 | if (gpiod_to_irq(desc) < 0) | |
368 | mode = 0; | |
369 | if (!show_direction && test_bit(FLAG_IS_OUT, &desc->flags)) | |
370 | mode = 0; | |
371 | } | |
372 | ||
373 | return mode; | |
374 | } | |
375 | ||
0915e6fe | 376 | static struct attribute *gpio_attrs[] = { |
ebbeba12 JH |
377 | &dev_attr_direction.attr, |
378 | &dev_attr_edge.attr, | |
0eb4c6c2 AC |
379 | &dev_attr_value.attr, |
380 | &dev_attr_active_low.attr, | |
381 | NULL, | |
382 | }; | |
ebbeba12 JH |
383 | |
384 | static const struct attribute_group gpio_group = { | |
385 | .attrs = gpio_attrs, | |
386 | .is_visible = gpio_is_visible, | |
387 | }; | |
388 | ||
389 | static const struct attribute_group *gpio_groups[] = { | |
390 | &gpio_group, | |
391 | NULL | |
392 | }; | |
0eb4c6c2 AC |
393 | |
394 | /* | |
395 | * /sys/class/gpio/gpiochipN/ | |
396 | * /base ... matching gpio_chip.base (N) | |
397 | * /label ... matching gpio_chip.label | |
398 | * /ngpio ... matching gpio_chip.ngpio | |
399 | */ | |
400 | ||
6beac9d1 | 401 | static ssize_t base_show(struct device *dev, |
0eb4c6c2 AC |
402 | struct device_attribute *attr, char *buf) |
403 | { | |
404 | const struct gpio_chip *chip = dev_get_drvdata(dev); | |
405 | ||
406 | return sprintf(buf, "%d\n", chip->base); | |
407 | } | |
6beac9d1 | 408 | static DEVICE_ATTR_RO(base); |
0eb4c6c2 | 409 | |
6beac9d1 | 410 | static ssize_t label_show(struct device *dev, |
0eb4c6c2 AC |
411 | struct device_attribute *attr, char *buf) |
412 | { | |
413 | const struct gpio_chip *chip = dev_get_drvdata(dev); | |
414 | ||
415 | return sprintf(buf, "%s\n", chip->label ? : ""); | |
416 | } | |
6beac9d1 | 417 | static DEVICE_ATTR_RO(label); |
0eb4c6c2 | 418 | |
6beac9d1 | 419 | static ssize_t ngpio_show(struct device *dev, |
0eb4c6c2 AC |
420 | struct device_attribute *attr, char *buf) |
421 | { | |
422 | const struct gpio_chip *chip = dev_get_drvdata(dev); | |
423 | ||
424 | return sprintf(buf, "%u\n", chip->ngpio); | |
425 | } | |
6beac9d1 | 426 | static DEVICE_ATTR_RO(ngpio); |
0eb4c6c2 | 427 | |
121b6a79 | 428 | static struct attribute *gpiochip_attrs[] = { |
0eb4c6c2 AC |
429 | &dev_attr_base.attr, |
430 | &dev_attr_label.attr, | |
431 | &dev_attr_ngpio.attr, | |
432 | NULL, | |
433 | }; | |
121b6a79 | 434 | ATTRIBUTE_GROUPS(gpiochip); |
0eb4c6c2 | 435 | |
90b05b05 MH |
436 | static struct gpio_desc *gpio_to_valid_desc(int gpio) |
437 | { | |
438 | return gpio_is_valid(gpio) ? gpio_to_desc(gpio) : NULL; | |
439 | } | |
440 | ||
0eb4c6c2 AC |
441 | /* |
442 | * /sys/class/gpio/export ... write-only | |
443 | * integer N ... number of GPIO to export (full access) | |
444 | * /sys/class/gpio/unexport ... write-only | |
445 | * integer N ... number of GPIO to unexport | |
446 | */ | |
447 | static ssize_t export_store(struct class *class, | |
448 | struct class_attribute *attr, | |
449 | const char *buf, size_t len) | |
450 | { | |
451 | long gpio; | |
452 | struct gpio_desc *desc; | |
453 | int status; | |
454 | ||
455 | status = kstrtol(buf, 0, &gpio); | |
456 | if (status < 0) | |
457 | goto done; | |
458 | ||
90b05b05 | 459 | desc = gpio_to_valid_desc(gpio); |
0eb4c6c2 AC |
460 | /* reject invalid GPIOs */ |
461 | if (!desc) { | |
462 | pr_warn("%s: invalid GPIO %ld\n", __func__, gpio); | |
463 | return -EINVAL; | |
464 | } | |
465 | ||
466 | /* No extra locking here; FLAG_SYSFS just signifies that the | |
467 | * request and export were done by on behalf of userspace, so | |
468 | * they may be undone on its behalf too. | |
469 | */ | |
470 | ||
471 | status = gpiod_request(desc, "sysfs"); | |
472 | if (status < 0) { | |
473 | if (status == -EPROBE_DEFER) | |
474 | status = -ENODEV; | |
475 | goto done; | |
476 | } | |
477 | status = gpiod_export(desc, true); | |
478 | if (status < 0) | |
479 | gpiod_free(desc); | |
480 | else | |
481 | set_bit(FLAG_SYSFS, &desc->flags); | |
482 | ||
483 | done: | |
484 | if (status) | |
485 | pr_debug("%s: status %d\n", __func__, status); | |
486 | return status ? : len; | |
487 | } | |
d83bb159 | 488 | static CLASS_ATTR_WO(export); |
0eb4c6c2 AC |
489 | |
490 | static ssize_t unexport_store(struct class *class, | |
491 | struct class_attribute *attr, | |
492 | const char *buf, size_t len) | |
493 | { | |
494 | long gpio; | |
495 | struct gpio_desc *desc; | |
496 | int status; | |
497 | ||
498 | status = kstrtol(buf, 0, &gpio); | |
499 | if (status < 0) | |
500 | goto done; | |
501 | ||
90b05b05 | 502 | desc = gpio_to_valid_desc(gpio); |
0eb4c6c2 AC |
503 | /* reject bogus commands (gpio_unexport ignores them) */ |
504 | if (!desc) { | |
505 | pr_warn("%s: invalid GPIO %ld\n", __func__, gpio); | |
506 | return -EINVAL; | |
507 | } | |
508 | ||
509 | status = -EINVAL; | |
510 | ||
511 | /* No extra locking here; FLAG_SYSFS just signifies that the | |
512 | * request and export were done by on behalf of userspace, so | |
513 | * they may be undone on its behalf too. | |
514 | */ | |
515 | if (test_and_clear_bit(FLAG_SYSFS, &desc->flags)) { | |
516 | status = 0; | |
517 | gpiod_free(desc); | |
518 | } | |
519 | done: | |
520 | if (status) | |
521 | pr_debug("%s: status %d\n", __func__, status); | |
522 | return status ? : len; | |
523 | } | |
d83bb159 | 524 | static CLASS_ATTR_WO(unexport); |
0eb4c6c2 | 525 | |
d83bb159 GKH |
526 | static struct attribute *gpio_class_attrs[] = { |
527 | &class_attr_export.attr, | |
528 | &class_attr_unexport.attr, | |
529 | NULL, | |
0eb4c6c2 | 530 | }; |
d83bb159 | 531 | ATTRIBUTE_GROUPS(gpio_class); |
0eb4c6c2 AC |
532 | |
533 | static struct class gpio_class = { | |
534 | .name = "gpio", | |
535 | .owner = THIS_MODULE, | |
536 | ||
d83bb159 | 537 | .class_groups = gpio_class_groups, |
0eb4c6c2 AC |
538 | }; |
539 | ||
540 | ||
541 | /** | |
542 | * gpiod_export - export a GPIO through sysfs | |
2d9d0519 TR |
543 | * @desc: GPIO to make available, already requested |
544 | * @direction_may_change: true if userspace may change GPIO direction | |
0eb4c6c2 AC |
545 | * Context: arch_initcall or later |
546 | * | |
547 | * When drivers want to make a GPIO accessible to userspace after they | |
548 | * have requested it -- perhaps while debugging, or as part of their | |
549 | * public interface -- they may use this routine. If the GPIO can | |
550 | * change direction (some can't) and the caller allows it, userspace | |
551 | * will see "direction" sysfs attribute which may be used to change | |
552 | * the gpio's direction. A "value" attribute will always be provided. | |
553 | * | |
554 | * Returns zero on success, else an error. | |
555 | */ | |
556 | int gpiod_export(struct gpio_desc *desc, bool direction_may_change) | |
557 | { | |
483d8211 | 558 | struct gpio_chip *chip; |
ff2b1359 | 559 | struct gpio_device *gdev; |
c43960fb | 560 | struct gpiod_data *data; |
0eb4c6c2 AC |
561 | unsigned long flags; |
562 | int status; | |
563 | const char *ioname = NULL; | |
564 | struct device *dev; | |
565 | int offset; | |
566 | ||
567 | /* can't export until sysfs is available ... */ | |
568 | if (!gpio_class.p) { | |
569 | pr_debug("%s: called too early!\n", __func__); | |
570 | return -ENOENT; | |
571 | } | |
572 | ||
573 | if (!desc) { | |
574 | pr_debug("%s: invalid gpio descriptor\n", __func__); | |
575 | return -EINVAL; | |
576 | } | |
577 | ||
fdeb8e15 LW |
578 | gdev = desc->gdev; |
579 | chip = gdev->chip; | |
483d8211 | 580 | |
0eb4c6c2 AC |
581 | mutex_lock(&sysfs_lock); |
582 | ||
483d8211 | 583 | /* check if chip is being removed */ |
afbc4f31 | 584 | if (!chip || !gdev->mockdev) { |
483d8211 | 585 | status = -ENODEV; |
c43960fb | 586 | goto err_unlock; |
483d8211 JH |
587 | } |
588 | ||
0eb4c6c2 AC |
589 | spin_lock_irqsave(&gpio_lock, flags); |
590 | if (!test_bit(FLAG_REQUESTED, &desc->flags) || | |
591 | test_bit(FLAG_EXPORT, &desc->flags)) { | |
592 | spin_unlock_irqrestore(&gpio_lock, flags); | |
593 | gpiod_dbg(desc, "%s: unavailable (requested=%d, exported=%d)\n", | |
594 | __func__, | |
595 | test_bit(FLAG_REQUESTED, &desc->flags), | |
596 | test_bit(FLAG_EXPORT, &desc->flags)); | |
597 | status = -EPERM; | |
c43960fb | 598 | goto err_unlock; |
0eb4c6c2 | 599 | } |
0eb4c6c2 AC |
600 | spin_unlock_irqrestore(&gpio_lock, flags); |
601 | ||
c43960fb JH |
602 | data = kzalloc(sizeof(*data), GFP_KERNEL); |
603 | if (!data) { | |
604 | status = -ENOMEM; | |
605 | goto err_unlock; | |
606 | } | |
607 | ||
608 | data->desc = desc; | |
6ffcb797 | 609 | mutex_init(&data->mutex); |
427fdeef JH |
610 | if (chip->direction_input && chip->direction_output) |
611 | data->direction_can_change = direction_may_change; | |
612 | else | |
613 | data->direction_can_change = false; | |
c43960fb | 614 | |
0eb4c6c2 | 615 | offset = gpio_chip_hwgpio(desc); |
cecf58ab JH |
616 | if (chip->names && chip->names[offset]) |
617 | ioname = chip->names[offset]; | |
0eb4c6c2 | 618 | |
ff2b1359 | 619 | dev = device_create_with_groups(&gpio_class, &gdev->dev, |
c43960fb | 620 | MKDEV(0, 0), data, gpio_groups, |
0915e6fe JH |
621 | ioname ? ioname : "gpio%u", |
622 | desc_to_gpio(desc)); | |
0eb4c6c2 AC |
623 | if (IS_ERR(dev)) { |
624 | status = PTR_ERR(dev); | |
c43960fb | 625 | goto err_free_data; |
0eb4c6c2 AC |
626 | } |
627 | ||
0eb4c6c2 AC |
628 | set_bit(FLAG_EXPORT, &desc->flags); |
629 | mutex_unlock(&sysfs_lock); | |
630 | return 0; | |
631 | ||
c43960fb JH |
632 | err_free_data: |
633 | kfree(data); | |
634 | err_unlock: | |
0eb4c6c2 AC |
635 | mutex_unlock(&sysfs_lock); |
636 | gpiod_dbg(desc, "%s: status %d\n", __func__, status); | |
637 | return status; | |
638 | } | |
639 | EXPORT_SYMBOL_GPL(gpiod_export); | |
640 | ||
c43960fb | 641 | static int match_export(struct device *dev, const void *desc) |
0eb4c6c2 | 642 | { |
c43960fb JH |
643 | struct gpiod_data *data = dev_get_drvdata(dev); |
644 | ||
645 | return data->desc == desc; | |
0eb4c6c2 AC |
646 | } |
647 | ||
648 | /** | |
649 | * gpiod_export_link - create a sysfs link to an exported GPIO node | |
650 | * @dev: device under which to create symlink | |
651 | * @name: name of the symlink | |
2d9d0519 | 652 | * @desc: GPIO to create symlink to, already exported |
0eb4c6c2 AC |
653 | * |
654 | * Set up a symlink from /sys/.../dev/name to /sys/class/gpio/gpioN | |
655 | * node. Caller is responsible for unlinking. | |
656 | * | |
657 | * Returns zero on success, else an error. | |
658 | */ | |
659 | int gpiod_export_link(struct device *dev, const char *name, | |
660 | struct gpio_desc *desc) | |
661 | { | |
56d30ec1 JH |
662 | struct device *cdev; |
663 | int ret; | |
0eb4c6c2 AC |
664 | |
665 | if (!desc) { | |
666 | pr_warn("%s: invalid GPIO\n", __func__); | |
667 | return -EINVAL; | |
668 | } | |
669 | ||
56d30ec1 JH |
670 | cdev = class_find_device(&gpio_class, NULL, desc, match_export); |
671 | if (!cdev) | |
672 | return -ENODEV; | |
0eb4c6c2 | 673 | |
56d30ec1 JH |
674 | ret = sysfs_create_link(&dev->kobj, &cdev->kobj, name); |
675 | put_device(cdev); | |
0eb4c6c2 | 676 | |
56d30ec1 | 677 | return ret; |
0eb4c6c2 AC |
678 | } |
679 | EXPORT_SYMBOL_GPL(gpiod_export_link); | |
680 | ||
0eb4c6c2 | 681 | /** |
31963eb0 | 682 | * gpiod_unexport - reverse effect of gpiod_export() |
2d9d0519 | 683 | * @desc: GPIO to make unavailable |
0eb4c6c2 | 684 | * |
31963eb0 | 685 | * This is implicit on gpiod_free(). |
0eb4c6c2 AC |
686 | */ |
687 | void gpiod_unexport(struct gpio_desc *desc) | |
688 | { | |
72eba6f6 JH |
689 | struct gpiod_data *data; |
690 | struct device *dev; | |
0eb4c6c2 AC |
691 | |
692 | if (!desc) { | |
693 | pr_warn("%s: invalid GPIO\n", __func__); | |
694 | return; | |
695 | } | |
696 | ||
697 | mutex_lock(&sysfs_lock); | |
698 | ||
72eba6f6 JH |
699 | if (!test_bit(FLAG_EXPORT, &desc->flags)) |
700 | goto err_unlock; | |
0eb4c6c2 | 701 | |
72eba6f6 JH |
702 | dev = class_find_device(&gpio_class, NULL, desc, match_export); |
703 | if (!dev) | |
704 | goto err_unlock; | |
705 | ||
706 | data = dev_get_drvdata(dev); | |
707 | ||
72eba6f6 JH |
708 | clear_bit(FLAG_EXPORT, &desc->flags); |
709 | ||
710 | device_unregister(dev); | |
711 | ||
712 | /* | |
713 | * Release irq after deregistration to prevent race with edge_store. | |
714 | */ | |
cef1717b | 715 | if (data->irq_flags) |
72eba6f6 | 716 | gpio_sysfs_free_irq(dev); |
0eb4c6c2 AC |
717 | |
718 | mutex_unlock(&sysfs_lock); | |
719 | ||
72eba6f6 JH |
720 | put_device(dev); |
721 | kfree(data); | |
0eb4c6c2 | 722 | |
72eba6f6 JH |
723 | return; |
724 | ||
725 | err_unlock: | |
726 | mutex_unlock(&sysfs_lock); | |
0eb4c6c2 AC |
727 | } |
728 | EXPORT_SYMBOL_GPL(gpiod_unexport); | |
729 | ||
afbc4f31 | 730 | int gpiochip_sysfs_register(struct gpio_device *gdev) |
0eb4c6c2 | 731 | { |
0eb4c6c2 | 732 | struct device *dev; |
d27c1728 | 733 | struct device *parent; |
afbc4f31 | 734 | struct gpio_chip *chip = gdev->chip; |
0eb4c6c2 | 735 | |
426577bd JH |
736 | /* |
737 | * Many systems add gpio chips for SOC support very early, | |
0eb4c6c2 | 738 | * before driver model support is available. In those cases we |
426577bd | 739 | * register later, in gpiolib_sysfs_init() ... here we just |
0eb4c6c2 AC |
740 | * verify that _some_ field of gpio_class got initialized. |
741 | */ | |
742 | if (!gpio_class.p) | |
743 | return 0; | |
744 | ||
d27c1728 BJZ |
745 | /* |
746 | * For sysfs backward compatibility we need to preserve this | |
747 | * preferred parenting to the gpio_chip parent field, if set. | |
748 | */ | |
749 | if (chip->parent) | |
750 | parent = chip->parent; | |
751 | else | |
752 | parent = &gdev->dev; | |
753 | ||
0eb4c6c2 | 754 | /* use chip->base for the ID; it's already known to be unique */ |
d27c1728 | 755 | dev = device_create_with_groups(&gpio_class, parent, |
58383c78 | 756 | MKDEV(0, 0), |
121b6a79 JH |
757 | chip, gpiochip_groups, |
758 | "gpiochip%d", chip->base); | |
759 | if (IS_ERR(dev)) | |
6a4b6b0a | 760 | return PTR_ERR(dev); |
3ff74be5 JH |
761 | |
762 | mutex_lock(&sysfs_lock); | |
afbc4f31 | 763 | gdev->mockdev = dev; |
0eb4c6c2 AC |
764 | mutex_unlock(&sysfs_lock); |
765 | ||
6a4b6b0a | 766 | return 0; |
0eb4c6c2 AC |
767 | } |
768 | ||
afbc4f31 | 769 | void gpiochip_sysfs_unregister(struct gpio_device *gdev) |
0eb4c6c2 | 770 | { |
483d8211 | 771 | struct gpio_desc *desc; |
afbc4f31 | 772 | struct gpio_chip *chip = gdev->chip; |
483d8211 | 773 | unsigned int i; |
0eb4c6c2 | 774 | |
afbc4f31 | 775 | if (!gdev->mockdev) |
6a4b6b0a | 776 | return; |
0eb4c6c2 | 777 | |
afbc4f31 | 778 | device_unregister(gdev->mockdev); |
6a4b6b0a JH |
779 | |
780 | /* prevent further gpiod exports */ | |
781 | mutex_lock(&sysfs_lock); | |
afbc4f31 | 782 | gdev->mockdev = NULL; |
6a4b6b0a | 783 | mutex_unlock(&sysfs_lock); |
483d8211 JH |
784 | |
785 | /* unregister gpiod class devices owned by sysfs */ | |
786 | for (i = 0; i < chip->ngpio; i++) { | |
fdeb8e15 | 787 | desc = &gdev->descs[i]; |
483d8211 JH |
788 | if (test_and_clear_bit(FLAG_SYSFS, &desc->flags)) |
789 | gpiod_free(desc); | |
790 | } | |
0eb4c6c2 AC |
791 | } |
792 | ||
793 | static int __init gpiolib_sysfs_init(void) | |
794 | { | |
795 | int status; | |
796 | unsigned long flags; | |
ff2b1359 | 797 | struct gpio_device *gdev; |
0eb4c6c2 AC |
798 | |
799 | status = class_register(&gpio_class); | |
800 | if (status < 0) | |
801 | return status; | |
802 | ||
803 | /* Scan and register the gpio_chips which registered very | |
804 | * early (e.g. before the class_register above was called). | |
805 | * | |
806 | * We run before arch_initcall() so chip->dev nodes can have | |
807 | * registered, and so arch_initcall() can always gpio_export(). | |
808 | */ | |
809 | spin_lock_irqsave(&gpio_lock, flags); | |
ff2b1359 | 810 | list_for_each_entry(gdev, &gpio_devices, list) { |
afbc4f31 | 811 | if (gdev->mockdev) |
0eb4c6c2 AC |
812 | continue; |
813 | ||
14141a93 | 814 | /* |
426577bd JH |
815 | * TODO we yield gpio_lock here because |
816 | * gpiochip_sysfs_register() acquires a mutex. This is unsafe | |
817 | * and needs to be fixed. | |
14141a93 AC |
818 | * |
819 | * Also it would be nice to use gpiochip_find() here so we | |
820 | * can keep gpio_chips local to gpiolib.c, but the yield of | |
821 | * gpio_lock prevents us from doing this. | |
822 | */ | |
0eb4c6c2 | 823 | spin_unlock_irqrestore(&gpio_lock, flags); |
afbc4f31 | 824 | status = gpiochip_sysfs_register(gdev); |
0eb4c6c2 AC |
825 | spin_lock_irqsave(&gpio_lock, flags); |
826 | } | |
827 | spin_unlock_irqrestore(&gpio_lock, flags); | |
828 | ||
0eb4c6c2 AC |
829 | return status; |
830 | } | |
831 | postcore_initcall(gpiolib_sysfs_init); |