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dae5f0af | 1 | // SPDX-License-Identifier: GPL-2.0 |
0eb4c6c2 AC |
2 | #include <linux/idr.h> |
3 | #include <linux/mutex.h> | |
4 | #include <linux/device.h> | |
5 | #include <linux/sysfs.h> | |
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> |
1efba35a | 11 | #include <linux/ctype.h> |
0eb4c6c2 AC |
12 | |
13 | #include "gpiolib.h" | |
14 | ||
cef1717b JH |
15 | #define GPIO_IRQF_TRIGGER_FALLING BIT(0) |
16 | #define GPIO_IRQF_TRIGGER_RISING BIT(1) | |
17 | #define GPIO_IRQF_TRIGGER_BOTH (GPIO_IRQF_TRIGGER_FALLING | \ | |
18 | GPIO_IRQF_TRIGGER_RISING) | |
19 | ||
c43960fb JH |
20 | struct gpiod_data { |
21 | struct gpio_desc *desc; | |
6ffcb797 JH |
22 | |
23 | struct mutex mutex; | |
a08f5c21 | 24 | struct kernfs_node *value_kn; |
2ec74a95 | 25 | int irq; |
cef1717b | 26 | unsigned char irq_flags; |
427fdeef JH |
27 | |
28 | bool direction_can_change; | |
c43960fb JH |
29 | }; |
30 | ||
6ffcb797 JH |
31 | /* |
32 | * Lock to serialise gpiod export and unexport, and prevent re-export of | |
33 | * gpiod whose chip is being unregistered. | |
0eb4c6c2 AC |
34 | */ |
35 | static DEFINE_MUTEX(sysfs_lock); | |
36 | ||
37 | /* | |
38 | * /sys/class/gpio/gpioN... only for GPIOs that are exported | |
39 | * /direction | |
40 | * * MAY BE OMITTED if kernel won't allow direction changes | |
41 | * * is read/write as "in" or "out" | |
42 | * * may also be written as "high" or "low", initializing | |
43 | * output value as specified ("out" implies "low") | |
44 | * /value | |
45 | * * always readable, subject to hardware behavior | |
46 | * * may be writable, as zero/nonzero | |
47 | * /edge | |
48 | * * configures behavior of poll(2) on /value | |
49 | * * available only if pin can generate IRQs on input | |
50 | * * is read/write as "none", "falling", "rising", or "both" | |
51 | * /active_low | |
52 | * * configures polarity of /value | |
53 | * * is read/write as zero/nonzero | |
54 | * * also affects existing and subsequent "falling" and "rising" | |
55 | * /edge configuration | |
56 | */ | |
57 | ||
6beac9d1 | 58 | static ssize_t direction_show(struct device *dev, |
0eb4c6c2 AC |
59 | struct device_attribute *attr, char *buf) |
60 | { | |
c43960fb JH |
61 | struct gpiod_data *data = dev_get_drvdata(dev); |
62 | struct gpio_desc *desc = data->desc; | |
0eb4c6c2 AC |
63 | ssize_t status; |
64 | ||
6ffcb797 | 65 | mutex_lock(&data->mutex); |
0eb4c6c2 | 66 | |
f0b7866a JH |
67 | gpiod_get_direction(desc); |
68 | status = sprintf(buf, "%s\n", | |
0eb4c6c2 AC |
69 | test_bit(FLAG_IS_OUT, &desc->flags) |
70 | ? "out" : "in"); | |
0eb4c6c2 | 71 | |
6ffcb797 JH |
72 | mutex_unlock(&data->mutex); |
73 | ||
0eb4c6c2 AC |
74 | return status; |
75 | } | |
76 | ||
6beac9d1 | 77 | static ssize_t direction_store(struct device *dev, |
0eb4c6c2 AC |
78 | struct device_attribute *attr, const char *buf, size_t size) |
79 | { | |
c43960fb JH |
80 | struct gpiod_data *data = dev_get_drvdata(dev); |
81 | struct gpio_desc *desc = data->desc; | |
0eb4c6c2 AC |
82 | ssize_t status; |
83 | ||
6ffcb797 | 84 | mutex_lock(&data->mutex); |
0eb4c6c2 | 85 | |
f0b7866a | 86 | if (sysfs_streq(buf, "high")) |
0eb4c6c2 AC |
87 | status = gpiod_direction_output_raw(desc, 1); |
88 | else if (sysfs_streq(buf, "out") || sysfs_streq(buf, "low")) | |
89 | status = gpiod_direction_output_raw(desc, 0); | |
90 | else if (sysfs_streq(buf, "in")) | |
91 | status = gpiod_direction_input(desc); | |
92 | else | |
93 | status = -EINVAL; | |
94 | ||
6ffcb797 JH |
95 | mutex_unlock(&data->mutex); |
96 | ||
0eb4c6c2 AC |
97 | return status ? : size; |
98 | } | |
6beac9d1 | 99 | static DEVICE_ATTR_RW(direction); |
0eb4c6c2 | 100 | |
6beac9d1 | 101 | static ssize_t value_show(struct device *dev, |
0eb4c6c2 AC |
102 | struct device_attribute *attr, char *buf) |
103 | { | |
c43960fb JH |
104 | struct gpiod_data *data = dev_get_drvdata(dev); |
105 | struct gpio_desc *desc = data->desc; | |
0eb4c6c2 AC |
106 | ssize_t status; |
107 | ||
6ffcb797 | 108 | mutex_lock(&data->mutex); |
0eb4c6c2 | 109 | |
9295c012 CL |
110 | status = gpiod_get_value_cansleep(desc); |
111 | if (status < 0) | |
112 | goto err; | |
0eb4c6c2 | 113 | |
7a94b88c CL |
114 | buf[0] = '0' + status; |
115 | buf[1] = '\n'; | |
116 | status = 2; | |
9295c012 | 117 | err: |
6ffcb797 JH |
118 | mutex_unlock(&data->mutex); |
119 | ||
0eb4c6c2 AC |
120 | return status; |
121 | } | |
122 | ||
6beac9d1 | 123 | static ssize_t value_store(struct device *dev, |
0eb4c6c2 AC |
124 | struct device_attribute *attr, const char *buf, size_t size) |
125 | { | |
c43960fb JH |
126 | struct gpiod_data *data = dev_get_drvdata(dev); |
127 | struct gpio_desc *desc = data->desc; | |
1efba35a | 128 | ssize_t status = 0; |
0eb4c6c2 | 129 | |
6ffcb797 | 130 | mutex_lock(&data->mutex); |
0eb4c6c2 | 131 | |
f0b7866a | 132 | if (!test_bit(FLAG_IS_OUT, &desc->flags)) { |
0eb4c6c2 | 133 | status = -EPERM; |
f0b7866a | 134 | } else { |
0eb4c6c2 AC |
135 | long value; |
136 | ||
1efba35a CL |
137 | if (size <= 2 && isdigit(buf[0]) && |
138 | (size == 1 || buf[1] == '\n')) | |
139 | value = buf[0] - '0'; | |
140 | else | |
141 | status = kstrtol(buf, 0, &value); | |
0eb4c6c2 AC |
142 | if (status == 0) { |
143 | gpiod_set_value_cansleep(desc, value); | |
144 | status = size; | |
145 | } | |
146 | } | |
147 | ||
6ffcb797 JH |
148 | mutex_unlock(&data->mutex); |
149 | ||
0eb4c6c2 AC |
150 | return status; |
151 | } | |
7fda9100 | 152 | static DEVICE_ATTR_PREALLOC(value, S_IWUSR | S_IRUGO, value_show, value_store); |
0eb4c6c2 AC |
153 | |
154 | static irqreturn_t gpio_sysfs_irq(int irq, void *priv) | |
155 | { | |
a08f5c21 JH |
156 | struct gpiod_data *data = priv; |
157 | ||
158 | sysfs_notify_dirent(data->value_kn); | |
0eb4c6c2 | 159 | |
0eb4c6c2 AC |
160 | return IRQ_HANDLED; |
161 | } | |
162 | ||
6ffcb797 | 163 | /* Caller holds gpiod-data mutex. */ |
cef1717b | 164 | static int gpio_sysfs_request_irq(struct device *dev, unsigned char flags) |
0eb4c6c2 | 165 | { |
0f628508 JH |
166 | struct gpiod_data *data = dev_get_drvdata(dev); |
167 | struct gpio_desc *desc = data->desc; | |
0eb4c6c2 | 168 | unsigned long irq_flags; |
2ec74a95 | 169 | int ret; |
0eb4c6c2 | 170 | |
2ec74a95 JH |
171 | data->irq = gpiod_to_irq(desc); |
172 | if (data->irq < 0) | |
0eb4c6c2 AC |
173 | return -EIO; |
174 | ||
2ec74a95 JH |
175 | data->value_kn = sysfs_get_dirent(dev->kobj.sd, "value"); |
176 | if (!data->value_kn) | |
177 | return -ENODEV; | |
0eb4c6c2 AC |
178 | |
179 | irq_flags = IRQF_SHARED; | |
cef1717b | 180 | if (flags & GPIO_IRQF_TRIGGER_FALLING) |
0eb4c6c2 AC |
181 | irq_flags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ? |
182 | IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING; | |
cef1717b | 183 | if (flags & GPIO_IRQF_TRIGGER_RISING) |
0eb4c6c2 AC |
184 | irq_flags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ? |
185 | IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING; | |
186 | ||
52176d0d JH |
187 | /* |
188 | * FIXME: This should be done in the irq_request_resources callback | |
189 | * when the irq is requested, but a few drivers currently fail | |
190 | * to do so. | |
191 | * | |
192 | * Remove this redundant call (along with the corresponding | |
193 | * unlock) when those drivers have been fixed. | |
194 | */ | |
fdeb8e15 | 195 | ret = gpiochip_lock_as_irq(desc->gdev->chip, gpio_chip_hwgpio(desc)); |
0eb4c6c2 | 196 | if (ret < 0) |
2ec74a95 | 197 | goto err_put_kn; |
0eb4c6c2 | 198 | |
2ec74a95 | 199 | ret = request_any_context_irq(data->irq, gpio_sysfs_irq, irq_flags, |
a08f5c21 | 200 | "gpiolib", data); |
52176d0d JH |
201 | if (ret < 0) |
202 | goto err_unlock; | |
0eb4c6c2 | 203 | |
cef1717b | 204 | data->irq_flags = flags; |
2ec74a95 | 205 | |
0eb4c6c2 AC |
206 | return 0; |
207 | ||
52176d0d | 208 | err_unlock: |
fdeb8e15 | 209 | gpiochip_unlock_as_irq(desc->gdev->chip, gpio_chip_hwgpio(desc)); |
2ec74a95 JH |
210 | err_put_kn: |
211 | sysfs_put(data->value_kn); | |
212 | ||
0eb4c6c2 AC |
213 | return ret; |
214 | } | |
215 | ||
6ffcb797 JH |
216 | /* |
217 | * Caller holds gpiod-data mutex (unless called after class-device | |
218 | * deregistration). | |
219 | */ | |
2ec74a95 JH |
220 | static void gpio_sysfs_free_irq(struct device *dev) |
221 | { | |
222 | struct gpiod_data *data = dev_get_drvdata(dev); | |
223 | struct gpio_desc *desc = data->desc; | |
224 | ||
cef1717b | 225 | data->irq_flags = 0; |
2ec74a95 | 226 | free_irq(data->irq, data); |
fdeb8e15 | 227 | gpiochip_unlock_as_irq(desc->gdev->chip, gpio_chip_hwgpio(desc)); |
2ec74a95 JH |
228 | sysfs_put(data->value_kn); |
229 | } | |
230 | ||
0eb4c6c2 AC |
231 | static const struct { |
232 | const char *name; | |
cef1717b | 233 | unsigned char flags; |
0eb4c6c2 AC |
234 | } trigger_types[] = { |
235 | { "none", 0 }, | |
cef1717b JH |
236 | { "falling", GPIO_IRQF_TRIGGER_FALLING }, |
237 | { "rising", GPIO_IRQF_TRIGGER_RISING }, | |
238 | { "both", GPIO_IRQF_TRIGGER_BOTH }, | |
0eb4c6c2 AC |
239 | }; |
240 | ||
6beac9d1 | 241 | static ssize_t edge_show(struct device *dev, |
0eb4c6c2 AC |
242 | struct device_attribute *attr, char *buf) |
243 | { | |
c43960fb | 244 | struct gpiod_data *data = dev_get_drvdata(dev); |
f0b7866a JH |
245 | ssize_t status = 0; |
246 | int i; | |
0eb4c6c2 | 247 | |
6ffcb797 | 248 | mutex_lock(&data->mutex); |
0eb4c6c2 | 249 | |
f0b7866a | 250 | for (i = 0; i < ARRAY_SIZE(trigger_types); i++) { |
cef1717b | 251 | if (data->irq_flags == trigger_types[i].flags) { |
f0b7866a JH |
252 | status = sprintf(buf, "%s\n", trigger_types[i].name); |
253 | break; | |
254 | } | |
0eb4c6c2 AC |
255 | } |
256 | ||
6ffcb797 JH |
257 | mutex_unlock(&data->mutex); |
258 | ||
0eb4c6c2 AC |
259 | return status; |
260 | } | |
261 | ||
6beac9d1 | 262 | static ssize_t edge_store(struct device *dev, |
0eb4c6c2 AC |
263 | struct device_attribute *attr, const char *buf, size_t size) |
264 | { | |
b91e1807 | 265 | struct gpiod_data *data = dev_get_drvdata(dev); |
cef1717b | 266 | unsigned char flags; |
2ec74a95 | 267 | ssize_t status = size; |
e4339ce3 | 268 | int i; |
0eb4c6c2 | 269 | |
e4339ce3 | 270 | for (i = 0; i < ARRAY_SIZE(trigger_types); i++) { |
0eb4c6c2 | 271 | if (sysfs_streq(trigger_types[i].name, buf)) |
e4339ce3 JH |
272 | break; |
273 | } | |
274 | ||
275 | if (i == ARRAY_SIZE(trigger_types)) | |
276 | return -EINVAL; | |
0eb4c6c2 | 277 | |
b91e1807 JH |
278 | flags = trigger_types[i].flags; |
279 | ||
6ffcb797 | 280 | mutex_lock(&data->mutex); |
0eb4c6c2 | 281 | |
cef1717b | 282 | if (flags == data->irq_flags) { |
b91e1807 JH |
283 | status = size; |
284 | goto out_unlock; | |
285 | } | |
286 | ||
cef1717b | 287 | if (data->irq_flags) |
2ec74a95 JH |
288 | gpio_sysfs_free_irq(dev); |
289 | ||
290 | if (flags) { | |
291 | status = gpio_sysfs_request_irq(dev, flags); | |
292 | if (!status) | |
293 | status = size; | |
294 | } | |
0eb4c6c2 | 295 | |
b91e1807 | 296 | out_unlock: |
6ffcb797 | 297 | mutex_unlock(&data->mutex); |
0eb4c6c2 AC |
298 | |
299 | return status; | |
300 | } | |
6beac9d1 | 301 | static DEVICE_ATTR_RW(edge); |
0eb4c6c2 | 302 | |
6ffcb797 | 303 | /* Caller holds gpiod-data mutex. */ |
2f323b85 | 304 | static int gpio_sysfs_set_active_low(struct device *dev, int value) |
0eb4c6c2 | 305 | { |
0f628508 JH |
306 | struct gpiod_data *data = dev_get_drvdata(dev); |
307 | struct gpio_desc *desc = data->desc; | |
0eb4c6c2 | 308 | int status = 0; |
cef1717b | 309 | unsigned int flags = data->irq_flags; |
0eb4c6c2 AC |
310 | |
311 | if (!!test_bit(FLAG_ACTIVE_LOW, &desc->flags) == !!value) | |
312 | return 0; | |
313 | ||
314 | if (value) | |
315 | set_bit(FLAG_ACTIVE_LOW, &desc->flags); | |
316 | else | |
317 | clear_bit(FLAG_ACTIVE_LOW, &desc->flags); | |
318 | ||
319 | /* reconfigure poll(2) support if enabled on one edge only */ | |
cef1717b JH |
320 | if (flags == GPIO_IRQF_TRIGGER_FALLING || |
321 | flags == GPIO_IRQF_TRIGGER_RISING) { | |
2ec74a95 | 322 | gpio_sysfs_free_irq(dev); |
cef1717b | 323 | status = gpio_sysfs_request_irq(dev, flags); |
0eb4c6c2 AC |
324 | } |
325 | ||
326 | return status; | |
327 | } | |
328 | ||
6beac9d1 | 329 | static ssize_t active_low_show(struct device *dev, |
0eb4c6c2 AC |
330 | struct device_attribute *attr, char *buf) |
331 | { | |
c43960fb JH |
332 | struct gpiod_data *data = dev_get_drvdata(dev); |
333 | struct gpio_desc *desc = data->desc; | |
0eb4c6c2 AC |
334 | ssize_t status; |
335 | ||
6ffcb797 | 336 | mutex_lock(&data->mutex); |
0eb4c6c2 | 337 | |
f0b7866a | 338 | status = sprintf(buf, "%d\n", |
0eb4c6c2 AC |
339 | !!test_bit(FLAG_ACTIVE_LOW, &desc->flags)); |
340 | ||
6ffcb797 | 341 | mutex_unlock(&data->mutex); |
0eb4c6c2 AC |
342 | |
343 | return status; | |
344 | } | |
345 | ||
6beac9d1 | 346 | static ssize_t active_low_store(struct device *dev, |
0eb4c6c2 AC |
347 | struct device_attribute *attr, const char *buf, size_t size) |
348 | { | |
6ffcb797 | 349 | struct gpiod_data *data = dev_get_drvdata(dev); |
0eb4c6c2 | 350 | ssize_t status; |
f0b7866a | 351 | long value; |
0eb4c6c2 | 352 | |
6ffcb797 | 353 | mutex_lock(&data->mutex); |
0eb4c6c2 | 354 | |
f0b7866a JH |
355 | status = kstrtol(buf, 0, &value); |
356 | if (status == 0) | |
2f323b85 | 357 | status = gpio_sysfs_set_active_low(dev, value); |
0eb4c6c2 | 358 | |
6ffcb797 | 359 | mutex_unlock(&data->mutex); |
0eb4c6c2 AC |
360 | |
361 | return status ? : size; | |
362 | } | |
6beac9d1 | 363 | static DEVICE_ATTR_RW(active_low); |
0eb4c6c2 | 364 | |
ebbeba12 JH |
365 | static umode_t gpio_is_visible(struct kobject *kobj, struct attribute *attr, |
366 | int n) | |
367 | { | |
368 | struct device *dev = container_of(kobj, struct device, kobj); | |
c43960fb JH |
369 | struct gpiod_data *data = dev_get_drvdata(dev); |
370 | struct gpio_desc *desc = data->desc; | |
ebbeba12 | 371 | umode_t mode = attr->mode; |
427fdeef | 372 | bool show_direction = data->direction_can_change; |
ebbeba12 JH |
373 | |
374 | if (attr == &dev_attr_direction.attr) { | |
375 | if (!show_direction) | |
376 | mode = 0; | |
377 | } else if (attr == &dev_attr_edge.attr) { | |
378 | if (gpiod_to_irq(desc) < 0) | |
379 | mode = 0; | |
380 | if (!show_direction && test_bit(FLAG_IS_OUT, &desc->flags)) | |
381 | mode = 0; | |
382 | } | |
383 | ||
384 | return mode; | |
385 | } | |
386 | ||
0915e6fe | 387 | static struct attribute *gpio_attrs[] = { |
ebbeba12 JH |
388 | &dev_attr_direction.attr, |
389 | &dev_attr_edge.attr, | |
0eb4c6c2 AC |
390 | &dev_attr_value.attr, |
391 | &dev_attr_active_low.attr, | |
392 | NULL, | |
393 | }; | |
ebbeba12 JH |
394 | |
395 | static const struct attribute_group gpio_group = { | |
396 | .attrs = gpio_attrs, | |
397 | .is_visible = gpio_is_visible, | |
398 | }; | |
399 | ||
400 | static const struct attribute_group *gpio_groups[] = { | |
401 | &gpio_group, | |
402 | NULL | |
403 | }; | |
0eb4c6c2 AC |
404 | |
405 | /* | |
406 | * /sys/class/gpio/gpiochipN/ | |
407 | * /base ... matching gpio_chip.base (N) | |
408 | * /label ... matching gpio_chip.label | |
409 | * /ngpio ... matching gpio_chip.ngpio | |
410 | */ | |
411 | ||
6beac9d1 | 412 | static ssize_t base_show(struct device *dev, |
0eb4c6c2 AC |
413 | struct device_attribute *attr, char *buf) |
414 | { | |
415 | const struct gpio_chip *chip = dev_get_drvdata(dev); | |
416 | ||
417 | return sprintf(buf, "%d\n", chip->base); | |
418 | } | |
6beac9d1 | 419 | static DEVICE_ATTR_RO(base); |
0eb4c6c2 | 420 | |
6beac9d1 | 421 | static ssize_t label_show(struct device *dev, |
0eb4c6c2 AC |
422 | struct device_attribute *attr, char *buf) |
423 | { | |
424 | const struct gpio_chip *chip = dev_get_drvdata(dev); | |
425 | ||
426 | return sprintf(buf, "%s\n", chip->label ? : ""); | |
427 | } | |
6beac9d1 | 428 | static DEVICE_ATTR_RO(label); |
0eb4c6c2 | 429 | |
6beac9d1 | 430 | static ssize_t ngpio_show(struct device *dev, |
0eb4c6c2 AC |
431 | struct device_attribute *attr, char *buf) |
432 | { | |
433 | const struct gpio_chip *chip = dev_get_drvdata(dev); | |
434 | ||
435 | return sprintf(buf, "%u\n", chip->ngpio); | |
436 | } | |
6beac9d1 | 437 | static DEVICE_ATTR_RO(ngpio); |
0eb4c6c2 | 438 | |
121b6a79 | 439 | static struct attribute *gpiochip_attrs[] = { |
0eb4c6c2 AC |
440 | &dev_attr_base.attr, |
441 | &dev_attr_label.attr, | |
442 | &dev_attr_ngpio.attr, | |
443 | NULL, | |
444 | }; | |
121b6a79 | 445 | ATTRIBUTE_GROUPS(gpiochip); |
0eb4c6c2 AC |
446 | |
447 | /* | |
448 | * /sys/class/gpio/export ... write-only | |
449 | * integer N ... number of GPIO to export (full access) | |
450 | * /sys/class/gpio/unexport ... write-only | |
451 | * integer N ... number of GPIO to unexport | |
452 | */ | |
453 | static ssize_t export_store(struct class *class, | |
454 | struct class_attribute *attr, | |
455 | const char *buf, size_t len) | |
456 | { | |
457 | long gpio; | |
458 | struct gpio_desc *desc; | |
459 | int status; | |
460 | ||
461 | status = kstrtol(buf, 0, &gpio); | |
462 | if (status < 0) | |
463 | goto done; | |
464 | ||
f13a0b0b | 465 | desc = gpio_to_desc(gpio); |
0eb4c6c2 AC |
466 | /* reject invalid GPIOs */ |
467 | if (!desc) { | |
468 | pr_warn("%s: invalid GPIO %ld\n", __func__, gpio); | |
469 | return -EINVAL; | |
470 | } | |
471 | ||
472 | /* No extra locking here; FLAG_SYSFS just signifies that the | |
473 | * request and export were done by on behalf of userspace, so | |
474 | * they may be undone on its behalf too. | |
475 | */ | |
476 | ||
477 | status = gpiod_request(desc, "sysfs"); | |
478 | if (status < 0) { | |
479 | if (status == -EPROBE_DEFER) | |
480 | status = -ENODEV; | |
481 | goto done; | |
482 | } | |
e10f72bf AJ |
483 | |
484 | status = gpiod_set_transitory(desc, false); | |
485 | if (!status) { | |
486 | status = gpiod_export(desc, true); | |
487 | if (status < 0) | |
488 | gpiod_free(desc); | |
489 | else | |
490 | set_bit(FLAG_SYSFS, &desc->flags); | |
491 | } | |
0eb4c6c2 AC |
492 | |
493 | done: | |
494 | if (status) | |
495 | pr_debug("%s: status %d\n", __func__, status); | |
496 | return status ? : len; | |
497 | } | |
d83bb159 | 498 | static CLASS_ATTR_WO(export); |
0eb4c6c2 AC |
499 | |
500 | static ssize_t unexport_store(struct class *class, | |
501 | struct class_attribute *attr, | |
502 | const char *buf, size_t len) | |
503 | { | |
504 | long gpio; | |
505 | struct gpio_desc *desc; | |
506 | int status; | |
507 | ||
508 | status = kstrtol(buf, 0, &gpio); | |
509 | if (status < 0) | |
510 | goto done; | |
511 | ||
f13a0b0b | 512 | desc = gpio_to_desc(gpio); |
0eb4c6c2 AC |
513 | /* reject bogus commands (gpio_unexport ignores them) */ |
514 | if (!desc) { | |
515 | pr_warn("%s: invalid GPIO %ld\n", __func__, gpio); | |
516 | return -EINVAL; | |
517 | } | |
518 | ||
519 | status = -EINVAL; | |
520 | ||
521 | /* No extra locking here; FLAG_SYSFS just signifies that the | |
522 | * request and export were done by on behalf of userspace, so | |
523 | * they may be undone on its behalf too. | |
524 | */ | |
525 | if (test_and_clear_bit(FLAG_SYSFS, &desc->flags)) { | |
526 | status = 0; | |
527 | gpiod_free(desc); | |
528 | } | |
529 | done: | |
530 | if (status) | |
531 | pr_debug("%s: status %d\n", __func__, status); | |
532 | return status ? : len; | |
533 | } | |
d83bb159 | 534 | static CLASS_ATTR_WO(unexport); |
0eb4c6c2 | 535 | |
d83bb159 GKH |
536 | static struct attribute *gpio_class_attrs[] = { |
537 | &class_attr_export.attr, | |
538 | &class_attr_unexport.attr, | |
539 | NULL, | |
0eb4c6c2 | 540 | }; |
d83bb159 | 541 | ATTRIBUTE_GROUPS(gpio_class); |
0eb4c6c2 AC |
542 | |
543 | static struct class gpio_class = { | |
544 | .name = "gpio", | |
545 | .owner = THIS_MODULE, | |
546 | ||
d83bb159 | 547 | .class_groups = gpio_class_groups, |
0eb4c6c2 AC |
548 | }; |
549 | ||
550 | ||
551 | /** | |
552 | * gpiod_export - export a GPIO through sysfs | |
2d9d0519 TR |
553 | * @desc: GPIO to make available, already requested |
554 | * @direction_may_change: true if userspace may change GPIO direction | |
0eb4c6c2 AC |
555 | * Context: arch_initcall or later |
556 | * | |
557 | * When drivers want to make a GPIO accessible to userspace after they | |
558 | * have requested it -- perhaps while debugging, or as part of their | |
559 | * public interface -- they may use this routine. If the GPIO can | |
560 | * change direction (some can't) and the caller allows it, userspace | |
561 | * will see "direction" sysfs attribute which may be used to change | |
562 | * the gpio's direction. A "value" attribute will always be provided. | |
563 | * | |
564 | * Returns zero on success, else an error. | |
565 | */ | |
566 | int gpiod_export(struct gpio_desc *desc, bool direction_may_change) | |
567 | { | |
483d8211 | 568 | struct gpio_chip *chip; |
ff2b1359 | 569 | struct gpio_device *gdev; |
c43960fb | 570 | struct gpiod_data *data; |
0eb4c6c2 AC |
571 | unsigned long flags; |
572 | int status; | |
573 | const char *ioname = NULL; | |
574 | struct device *dev; | |
575 | int offset; | |
576 | ||
577 | /* can't export until sysfs is available ... */ | |
578 | if (!gpio_class.p) { | |
579 | pr_debug("%s: called too early!\n", __func__); | |
580 | return -ENOENT; | |
581 | } | |
582 | ||
583 | if (!desc) { | |
584 | pr_debug("%s: invalid gpio descriptor\n", __func__); | |
585 | return -EINVAL; | |
586 | } | |
587 | ||
fdeb8e15 LW |
588 | gdev = desc->gdev; |
589 | chip = gdev->chip; | |
483d8211 | 590 | |
0eb4c6c2 AC |
591 | mutex_lock(&sysfs_lock); |
592 | ||
483d8211 | 593 | /* check if chip is being removed */ |
afbc4f31 | 594 | if (!chip || !gdev->mockdev) { |
483d8211 | 595 | status = -ENODEV; |
c43960fb | 596 | goto err_unlock; |
483d8211 JH |
597 | } |
598 | ||
0eb4c6c2 AC |
599 | spin_lock_irqsave(&gpio_lock, flags); |
600 | if (!test_bit(FLAG_REQUESTED, &desc->flags) || | |
601 | test_bit(FLAG_EXPORT, &desc->flags)) { | |
602 | spin_unlock_irqrestore(&gpio_lock, flags); | |
603 | gpiod_dbg(desc, "%s: unavailable (requested=%d, exported=%d)\n", | |
604 | __func__, | |
605 | test_bit(FLAG_REQUESTED, &desc->flags), | |
606 | test_bit(FLAG_EXPORT, &desc->flags)); | |
607 | status = -EPERM; | |
c43960fb | 608 | goto err_unlock; |
0eb4c6c2 | 609 | } |
0eb4c6c2 AC |
610 | spin_unlock_irqrestore(&gpio_lock, flags); |
611 | ||
c43960fb JH |
612 | data = kzalloc(sizeof(*data), GFP_KERNEL); |
613 | if (!data) { | |
614 | status = -ENOMEM; | |
615 | goto err_unlock; | |
616 | } | |
617 | ||
618 | data->desc = desc; | |
6ffcb797 | 619 | mutex_init(&data->mutex); |
427fdeef JH |
620 | if (chip->direction_input && chip->direction_output) |
621 | data->direction_can_change = direction_may_change; | |
622 | else | |
623 | data->direction_can_change = false; | |
c43960fb | 624 | |
0eb4c6c2 | 625 | offset = gpio_chip_hwgpio(desc); |
cecf58ab JH |
626 | if (chip->names && chip->names[offset]) |
627 | ioname = chip->names[offset]; | |
0eb4c6c2 | 628 | |
ff2b1359 | 629 | dev = device_create_with_groups(&gpio_class, &gdev->dev, |
c43960fb | 630 | MKDEV(0, 0), data, gpio_groups, |
0915e6fe JH |
631 | ioname ? ioname : "gpio%u", |
632 | desc_to_gpio(desc)); | |
0eb4c6c2 AC |
633 | if (IS_ERR(dev)) { |
634 | status = PTR_ERR(dev); | |
c43960fb | 635 | goto err_free_data; |
0eb4c6c2 AC |
636 | } |
637 | ||
0eb4c6c2 AC |
638 | set_bit(FLAG_EXPORT, &desc->flags); |
639 | mutex_unlock(&sysfs_lock); | |
640 | return 0; | |
641 | ||
c43960fb JH |
642 | err_free_data: |
643 | kfree(data); | |
644 | err_unlock: | |
0eb4c6c2 AC |
645 | mutex_unlock(&sysfs_lock); |
646 | gpiod_dbg(desc, "%s: status %d\n", __func__, status); | |
647 | return status; | |
648 | } | |
649 | EXPORT_SYMBOL_GPL(gpiod_export); | |
650 | ||
c43960fb | 651 | static int match_export(struct device *dev, const void *desc) |
0eb4c6c2 | 652 | { |
c43960fb JH |
653 | struct gpiod_data *data = dev_get_drvdata(dev); |
654 | ||
655 | return data->desc == desc; | |
0eb4c6c2 AC |
656 | } |
657 | ||
658 | /** | |
659 | * gpiod_export_link - create a sysfs link to an exported GPIO node | |
660 | * @dev: device under which to create symlink | |
661 | * @name: name of the symlink | |
2d9d0519 | 662 | * @desc: GPIO to create symlink to, already exported |
0eb4c6c2 AC |
663 | * |
664 | * Set up a symlink from /sys/.../dev/name to /sys/class/gpio/gpioN | |
665 | * node. Caller is responsible for unlinking. | |
666 | * | |
667 | * Returns zero on success, else an error. | |
668 | */ | |
669 | int gpiod_export_link(struct device *dev, const char *name, | |
670 | struct gpio_desc *desc) | |
671 | { | |
56d30ec1 JH |
672 | struct device *cdev; |
673 | int ret; | |
0eb4c6c2 AC |
674 | |
675 | if (!desc) { | |
676 | pr_warn("%s: invalid GPIO\n", __func__); | |
677 | return -EINVAL; | |
678 | } | |
679 | ||
56d30ec1 JH |
680 | cdev = class_find_device(&gpio_class, NULL, desc, match_export); |
681 | if (!cdev) | |
682 | return -ENODEV; | |
0eb4c6c2 | 683 | |
56d30ec1 JH |
684 | ret = sysfs_create_link(&dev->kobj, &cdev->kobj, name); |
685 | put_device(cdev); | |
0eb4c6c2 | 686 | |
56d30ec1 | 687 | return ret; |
0eb4c6c2 AC |
688 | } |
689 | EXPORT_SYMBOL_GPL(gpiod_export_link); | |
690 | ||
0eb4c6c2 | 691 | /** |
31963eb0 | 692 | * gpiod_unexport - reverse effect of gpiod_export() |
2d9d0519 | 693 | * @desc: GPIO to make unavailable |
0eb4c6c2 | 694 | * |
31963eb0 | 695 | * This is implicit on gpiod_free(). |
0eb4c6c2 AC |
696 | */ |
697 | void gpiod_unexport(struct gpio_desc *desc) | |
698 | { | |
72eba6f6 JH |
699 | struct gpiod_data *data; |
700 | struct device *dev; | |
0eb4c6c2 AC |
701 | |
702 | if (!desc) { | |
703 | pr_warn("%s: invalid GPIO\n", __func__); | |
704 | return; | |
705 | } | |
706 | ||
707 | mutex_lock(&sysfs_lock); | |
708 | ||
72eba6f6 JH |
709 | if (!test_bit(FLAG_EXPORT, &desc->flags)) |
710 | goto err_unlock; | |
0eb4c6c2 | 711 | |
72eba6f6 JH |
712 | dev = class_find_device(&gpio_class, NULL, desc, match_export); |
713 | if (!dev) | |
714 | goto err_unlock; | |
715 | ||
716 | data = dev_get_drvdata(dev); | |
717 | ||
72eba6f6 JH |
718 | clear_bit(FLAG_EXPORT, &desc->flags); |
719 | ||
720 | device_unregister(dev); | |
721 | ||
722 | /* | |
723 | * Release irq after deregistration to prevent race with edge_store. | |
724 | */ | |
cef1717b | 725 | if (data->irq_flags) |
72eba6f6 | 726 | gpio_sysfs_free_irq(dev); |
0eb4c6c2 AC |
727 | |
728 | mutex_unlock(&sysfs_lock); | |
729 | ||
72eba6f6 JH |
730 | put_device(dev); |
731 | kfree(data); | |
0eb4c6c2 | 732 | |
72eba6f6 JH |
733 | return; |
734 | ||
735 | err_unlock: | |
736 | mutex_unlock(&sysfs_lock); | |
0eb4c6c2 AC |
737 | } |
738 | EXPORT_SYMBOL_GPL(gpiod_unexport); | |
739 | ||
afbc4f31 | 740 | int gpiochip_sysfs_register(struct gpio_device *gdev) |
0eb4c6c2 | 741 | { |
0eb4c6c2 | 742 | struct device *dev; |
d27c1728 | 743 | struct device *parent; |
afbc4f31 | 744 | struct gpio_chip *chip = gdev->chip; |
0eb4c6c2 | 745 | |
426577bd JH |
746 | /* |
747 | * Many systems add gpio chips for SOC support very early, | |
0eb4c6c2 | 748 | * before driver model support is available. In those cases we |
426577bd | 749 | * register later, in gpiolib_sysfs_init() ... here we just |
0eb4c6c2 AC |
750 | * verify that _some_ field of gpio_class got initialized. |
751 | */ | |
752 | if (!gpio_class.p) | |
753 | return 0; | |
754 | ||
d27c1728 BJZ |
755 | /* |
756 | * For sysfs backward compatibility we need to preserve this | |
757 | * preferred parenting to the gpio_chip parent field, if set. | |
758 | */ | |
759 | if (chip->parent) | |
760 | parent = chip->parent; | |
761 | else | |
762 | parent = &gdev->dev; | |
763 | ||
0eb4c6c2 | 764 | /* use chip->base for the ID; it's already known to be unique */ |
d27c1728 | 765 | dev = device_create_with_groups(&gpio_class, parent, |
58383c78 | 766 | MKDEV(0, 0), |
121b6a79 JH |
767 | chip, gpiochip_groups, |
768 | "gpiochip%d", chip->base); | |
769 | if (IS_ERR(dev)) | |
6a4b6b0a | 770 | return PTR_ERR(dev); |
3ff74be5 JH |
771 | |
772 | mutex_lock(&sysfs_lock); | |
afbc4f31 | 773 | gdev->mockdev = dev; |
0eb4c6c2 AC |
774 | mutex_unlock(&sysfs_lock); |
775 | ||
6a4b6b0a | 776 | return 0; |
0eb4c6c2 AC |
777 | } |
778 | ||
afbc4f31 | 779 | void gpiochip_sysfs_unregister(struct gpio_device *gdev) |
0eb4c6c2 | 780 | { |
483d8211 | 781 | struct gpio_desc *desc; |
afbc4f31 | 782 | struct gpio_chip *chip = gdev->chip; |
483d8211 | 783 | unsigned int i; |
0eb4c6c2 | 784 | |
afbc4f31 | 785 | if (!gdev->mockdev) |
6a4b6b0a | 786 | return; |
0eb4c6c2 | 787 | |
afbc4f31 | 788 | device_unregister(gdev->mockdev); |
6a4b6b0a JH |
789 | |
790 | /* prevent further gpiod exports */ | |
791 | mutex_lock(&sysfs_lock); | |
afbc4f31 | 792 | gdev->mockdev = NULL; |
6a4b6b0a | 793 | mutex_unlock(&sysfs_lock); |
483d8211 JH |
794 | |
795 | /* unregister gpiod class devices owned by sysfs */ | |
796 | for (i = 0; i < chip->ngpio; i++) { | |
fdeb8e15 | 797 | desc = &gdev->descs[i]; |
483d8211 JH |
798 | if (test_and_clear_bit(FLAG_SYSFS, &desc->flags)) |
799 | gpiod_free(desc); | |
800 | } | |
0eb4c6c2 AC |
801 | } |
802 | ||
803 | static int __init gpiolib_sysfs_init(void) | |
804 | { | |
805 | int status; | |
806 | unsigned long flags; | |
ff2b1359 | 807 | struct gpio_device *gdev; |
0eb4c6c2 AC |
808 | |
809 | status = class_register(&gpio_class); | |
810 | if (status < 0) | |
811 | return status; | |
812 | ||
813 | /* Scan and register the gpio_chips which registered very | |
814 | * early (e.g. before the class_register above was called). | |
815 | * | |
816 | * We run before arch_initcall() so chip->dev nodes can have | |
817 | * registered, and so arch_initcall() can always gpio_export(). | |
818 | */ | |
819 | spin_lock_irqsave(&gpio_lock, flags); | |
ff2b1359 | 820 | list_for_each_entry(gdev, &gpio_devices, list) { |
afbc4f31 | 821 | if (gdev->mockdev) |
0eb4c6c2 AC |
822 | continue; |
823 | ||
14141a93 | 824 | /* |
426577bd JH |
825 | * TODO we yield gpio_lock here because |
826 | * gpiochip_sysfs_register() acquires a mutex. This is unsafe | |
827 | * and needs to be fixed. | |
14141a93 AC |
828 | * |
829 | * Also it would be nice to use gpiochip_find() here so we | |
830 | * can keep gpio_chips local to gpiolib.c, but the yield of | |
831 | * gpio_lock prevents us from doing this. | |
832 | */ | |
0eb4c6c2 | 833 | spin_unlock_irqrestore(&gpio_lock, flags); |
afbc4f31 | 834 | status = gpiochip_sysfs_register(gdev); |
0eb4c6c2 AC |
835 | spin_lock_irqsave(&gpio_lock, flags); |
836 | } | |
837 | spin_unlock_irqrestore(&gpio_lock, flags); | |
838 | ||
0eb4c6c2 AC |
839 | return status; |
840 | } | |
841 | postcore_initcall(gpiolib_sysfs_init); |