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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" | |
ef087d8e | 14 | #include "gpiolib-sysfs.h" |
0eb4c6c2 | 15 | |
667630ed | 16 | #define GPIO_IRQF_TRIGGER_NONE 0 |
cef1717b JH |
17 | #define GPIO_IRQF_TRIGGER_FALLING BIT(0) |
18 | #define GPIO_IRQF_TRIGGER_RISING BIT(1) | |
19 | #define GPIO_IRQF_TRIGGER_BOTH (GPIO_IRQF_TRIGGER_FALLING | \ | |
20 | GPIO_IRQF_TRIGGER_RISING) | |
21 | ||
c43960fb JH |
22 | struct gpiod_data { |
23 | struct gpio_desc *desc; | |
6ffcb797 JH |
24 | |
25 | struct mutex mutex; | |
a08f5c21 | 26 | struct kernfs_node *value_kn; |
2ec74a95 | 27 | int irq; |
cef1717b | 28 | unsigned char irq_flags; |
427fdeef JH |
29 | |
30 | bool direction_can_change; | |
c43960fb JH |
31 | }; |
32 | ||
6ffcb797 JH |
33 | /* |
34 | * Lock to serialise gpiod export and unexport, and prevent re-export of | |
35 | * gpiod whose chip is being unregistered. | |
0eb4c6c2 AC |
36 | */ |
37 | static DEFINE_MUTEX(sysfs_lock); | |
38 | ||
39 | /* | |
40 | * /sys/class/gpio/gpioN... only for GPIOs that are exported | |
41 | * /direction | |
42 | * * MAY BE OMITTED if kernel won't allow direction changes | |
43 | * * is read/write as "in" or "out" | |
44 | * * may also be written as "high" or "low", initializing | |
45 | * output value as specified ("out" implies "low") | |
46 | * /value | |
47 | * * always readable, subject to hardware behavior | |
48 | * * may be writable, as zero/nonzero | |
49 | * /edge | |
50 | * * configures behavior of poll(2) on /value | |
51 | * * available only if pin can generate IRQs on input | |
52 | * * is read/write as "none", "falling", "rising", or "both" | |
53 | * /active_low | |
54 | * * configures polarity of /value | |
55 | * * is read/write as zero/nonzero | |
56 | * * also affects existing and subsequent "falling" and "rising" | |
57 | * /edge configuration | |
58 | */ | |
59 | ||
6beac9d1 | 60 | static ssize_t direction_show(struct device *dev, |
0eb4c6c2 AC |
61 | struct device_attribute *attr, char *buf) |
62 | { | |
c43960fb JH |
63 | struct gpiod_data *data = dev_get_drvdata(dev); |
64 | struct gpio_desc *desc = data->desc; | |
e28747da | 65 | int value; |
0eb4c6c2 | 66 | |
6ffcb797 | 67 | mutex_lock(&data->mutex); |
0eb4c6c2 | 68 | |
f0b7866a | 69 | gpiod_get_direction(desc); |
e28747da | 70 | value = !!test_bit(FLAG_IS_OUT, &desc->flags); |
0eb4c6c2 | 71 | |
6ffcb797 JH |
72 | mutex_unlock(&data->mutex); |
73 | ||
e28747da | 74 | return sysfs_emit(buf, "%s\n", value ? "out" : "in"); |
0eb4c6c2 AC |
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 | 110 | status = gpiod_get_value_cansleep(desc); |
0eb4c6c2 | 111 | |
6ffcb797 JH |
112 | mutex_unlock(&data->mutex); |
113 | ||
e28747da AS |
114 | if (status < 0) |
115 | return status; | |
116 | ||
117 | return sysfs_emit(buf, "%zd\n", status); | |
0eb4c6c2 AC |
118 | } |
119 | ||
6beac9d1 | 120 | static ssize_t value_store(struct device *dev, |
0eb4c6c2 AC |
121 | struct device_attribute *attr, const char *buf, size_t size) |
122 | { | |
c43960fb JH |
123 | struct gpiod_data *data = dev_get_drvdata(dev); |
124 | struct gpio_desc *desc = data->desc; | |
6b3c1791 AS |
125 | ssize_t status; |
126 | long value; | |
127 | ||
128 | status = kstrtol(buf, 0, &value); | |
0eb4c6c2 | 129 | |
6ffcb797 | 130 | mutex_lock(&data->mutex); |
0eb4c6c2 | 131 | |
f0b7866a | 132 | if (!test_bit(FLAG_IS_OUT, &desc->flags)) { |
0eb4c6c2 | 133 | status = -EPERM; |
6b3c1791 AS |
134 | } else if (status == 0) { |
135 | gpiod_set_value_cansleep(desc, value); | |
136 | status = size; | |
0eb4c6c2 AC |
137 | } |
138 | ||
6ffcb797 JH |
139 | mutex_unlock(&data->mutex); |
140 | ||
0eb4c6c2 AC |
141 | return status; |
142 | } | |
7fda9100 | 143 | static DEVICE_ATTR_PREALLOC(value, S_IWUSR | S_IRUGO, value_show, value_store); |
0eb4c6c2 AC |
144 | |
145 | static irqreturn_t gpio_sysfs_irq(int irq, void *priv) | |
146 | { | |
a08f5c21 JH |
147 | struct gpiod_data *data = priv; |
148 | ||
149 | sysfs_notify_dirent(data->value_kn); | |
0eb4c6c2 | 150 | |
0eb4c6c2 AC |
151 | return IRQ_HANDLED; |
152 | } | |
153 | ||
6ffcb797 | 154 | /* Caller holds gpiod-data mutex. */ |
cef1717b | 155 | static int gpio_sysfs_request_irq(struct device *dev, unsigned char flags) |
0eb4c6c2 | 156 | { |
0f628508 JH |
157 | struct gpiod_data *data = dev_get_drvdata(dev); |
158 | struct gpio_desc *desc = data->desc; | |
0eb4c6c2 | 159 | unsigned long irq_flags; |
2ec74a95 | 160 | int ret; |
0eb4c6c2 | 161 | |
2ec74a95 JH |
162 | data->irq = gpiod_to_irq(desc); |
163 | if (data->irq < 0) | |
0eb4c6c2 AC |
164 | return -EIO; |
165 | ||
2ec74a95 JH |
166 | data->value_kn = sysfs_get_dirent(dev->kobj.sd, "value"); |
167 | if (!data->value_kn) | |
168 | return -ENODEV; | |
0eb4c6c2 AC |
169 | |
170 | irq_flags = IRQF_SHARED; | |
cef1717b | 171 | if (flags & GPIO_IRQF_TRIGGER_FALLING) |
0eb4c6c2 AC |
172 | irq_flags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ? |
173 | IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING; | |
cef1717b | 174 | if (flags & GPIO_IRQF_TRIGGER_RISING) |
0eb4c6c2 AC |
175 | irq_flags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ? |
176 | IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING; | |
177 | ||
52176d0d JH |
178 | /* |
179 | * FIXME: This should be done in the irq_request_resources callback | |
180 | * when the irq is requested, but a few drivers currently fail | |
181 | * to do so. | |
182 | * | |
183 | * Remove this redundant call (along with the corresponding | |
184 | * unlock) when those drivers have been fixed. | |
185 | */ | |
fdeb8e15 | 186 | ret = gpiochip_lock_as_irq(desc->gdev->chip, gpio_chip_hwgpio(desc)); |
0eb4c6c2 | 187 | if (ret < 0) |
2ec74a95 | 188 | goto err_put_kn; |
0eb4c6c2 | 189 | |
2ec74a95 | 190 | ret = request_any_context_irq(data->irq, gpio_sysfs_irq, irq_flags, |
a08f5c21 | 191 | "gpiolib", data); |
52176d0d JH |
192 | if (ret < 0) |
193 | goto err_unlock; | |
0eb4c6c2 | 194 | |
cef1717b | 195 | data->irq_flags = flags; |
2ec74a95 | 196 | |
0eb4c6c2 AC |
197 | return 0; |
198 | ||
52176d0d | 199 | err_unlock: |
fdeb8e15 | 200 | gpiochip_unlock_as_irq(desc->gdev->chip, gpio_chip_hwgpio(desc)); |
2ec74a95 JH |
201 | err_put_kn: |
202 | sysfs_put(data->value_kn); | |
203 | ||
0eb4c6c2 AC |
204 | return ret; |
205 | } | |
206 | ||
6ffcb797 JH |
207 | /* |
208 | * Caller holds gpiod-data mutex (unless called after class-device | |
209 | * deregistration). | |
210 | */ | |
2ec74a95 JH |
211 | static void gpio_sysfs_free_irq(struct device *dev) |
212 | { | |
213 | struct gpiod_data *data = dev_get_drvdata(dev); | |
214 | struct gpio_desc *desc = data->desc; | |
215 | ||
cef1717b | 216 | data->irq_flags = 0; |
2ec74a95 | 217 | free_irq(data->irq, data); |
fdeb8e15 | 218 | gpiochip_unlock_as_irq(desc->gdev->chip, gpio_chip_hwgpio(desc)); |
2ec74a95 JH |
219 | sysfs_put(data->value_kn); |
220 | } | |
221 | ||
667630ed AS |
222 | static const char * const trigger_names[] = { |
223 | [GPIO_IRQF_TRIGGER_NONE] = "none", | |
224 | [GPIO_IRQF_TRIGGER_FALLING] = "falling", | |
225 | [GPIO_IRQF_TRIGGER_RISING] = "rising", | |
226 | [GPIO_IRQF_TRIGGER_BOTH] = "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); |
667630ed | 233 | int flags; |
0eb4c6c2 | 234 | |
6ffcb797 | 235 | mutex_lock(&data->mutex); |
0eb4c6c2 | 236 | |
667630ed | 237 | flags = data->irq_flags; |
0eb4c6c2 | 238 | |
6ffcb797 JH |
239 | mutex_unlock(&data->mutex); |
240 | ||
667630ed | 241 | if (flags >= ARRAY_SIZE(trigger_names)) |
e28747da AS |
242 | return 0; |
243 | ||
667630ed | 244 | return sysfs_emit(buf, "%s\n", trigger_names[flags]); |
0eb4c6c2 AC |
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 | 250 | struct gpiod_data *data = dev_get_drvdata(dev); |
2ec74a95 | 251 | ssize_t status = size; |
667630ed | 252 | int flags; |
e4339ce3 | 253 | |
667630ed AS |
254 | flags = sysfs_match_string(trigger_names, buf); |
255 | if (flags < 0) | |
256 | return flags; | |
b91e1807 | 257 | |
6ffcb797 | 258 | mutex_lock(&data->mutex); |
0eb4c6c2 | 259 | |
cef1717b | 260 | if (flags == data->irq_flags) { |
b91e1807 JH |
261 | status = size; |
262 | goto out_unlock; | |
263 | } | |
264 | ||
cef1717b | 265 | if (data->irq_flags) |
2ec74a95 JH |
266 | gpio_sysfs_free_irq(dev); |
267 | ||
268 | if (flags) { | |
269 | status = gpio_sysfs_request_irq(dev, flags); | |
270 | if (!status) | |
271 | status = size; | |
272 | } | |
0eb4c6c2 | 273 | |
b91e1807 | 274 | out_unlock: |
6ffcb797 | 275 | mutex_unlock(&data->mutex); |
0eb4c6c2 AC |
276 | |
277 | return status; | |
278 | } | |
6beac9d1 | 279 | static DEVICE_ATTR_RW(edge); |
0eb4c6c2 | 280 | |
6ffcb797 | 281 | /* Caller holds gpiod-data mutex. */ |
2f323b85 | 282 | static int gpio_sysfs_set_active_low(struct device *dev, int value) |
0eb4c6c2 | 283 | { |
0f628508 JH |
284 | struct gpiod_data *data = dev_get_drvdata(dev); |
285 | struct gpio_desc *desc = data->desc; | |
0eb4c6c2 | 286 | int status = 0; |
cef1717b | 287 | unsigned int flags = data->irq_flags; |
0eb4c6c2 AC |
288 | |
289 | if (!!test_bit(FLAG_ACTIVE_LOW, &desc->flags) == !!value) | |
290 | return 0; | |
291 | ||
fd80b8ba | 292 | assign_bit(FLAG_ACTIVE_LOW, &desc->flags, value); |
0eb4c6c2 AC |
293 | |
294 | /* reconfigure poll(2) support if enabled on one edge only */ | |
cef1717b JH |
295 | if (flags == GPIO_IRQF_TRIGGER_FALLING || |
296 | flags == GPIO_IRQF_TRIGGER_RISING) { | |
2ec74a95 | 297 | gpio_sysfs_free_irq(dev); |
cef1717b | 298 | status = gpio_sysfs_request_irq(dev, flags); |
0eb4c6c2 AC |
299 | } |
300 | ||
301 | return status; | |
302 | } | |
303 | ||
6beac9d1 | 304 | static ssize_t active_low_show(struct device *dev, |
0eb4c6c2 AC |
305 | struct device_attribute *attr, char *buf) |
306 | { | |
c43960fb JH |
307 | struct gpiod_data *data = dev_get_drvdata(dev); |
308 | struct gpio_desc *desc = data->desc; | |
e28747da | 309 | int value; |
0eb4c6c2 | 310 | |
6ffcb797 | 311 | mutex_lock(&data->mutex); |
0eb4c6c2 | 312 | |
e28747da | 313 | value = !!test_bit(FLAG_ACTIVE_LOW, &desc->flags); |
0eb4c6c2 | 314 | |
6ffcb797 | 315 | mutex_unlock(&data->mutex); |
0eb4c6c2 | 316 | |
e28747da | 317 | return sysfs_emit(buf, "%d\n", value); |
0eb4c6c2 AC |
318 | } |
319 | ||
6beac9d1 | 320 | static ssize_t active_low_store(struct device *dev, |
0eb4c6c2 AC |
321 | struct device_attribute *attr, const char *buf, size_t size) |
322 | { | |
6ffcb797 | 323 | struct gpiod_data *data = dev_get_drvdata(dev); |
0eb4c6c2 | 324 | ssize_t status; |
f0b7866a | 325 | long value; |
0eb4c6c2 | 326 | |
6b3c1791 AS |
327 | status = kstrtol(buf, 0, &value); |
328 | if (status) | |
329 | return status; | |
330 | ||
6ffcb797 | 331 | mutex_lock(&data->mutex); |
0eb4c6c2 | 332 | |
6b3c1791 | 333 | status = gpio_sysfs_set_active_low(dev, value); |
0eb4c6c2 | 334 | |
6ffcb797 | 335 | mutex_unlock(&data->mutex); |
0eb4c6c2 AC |
336 | |
337 | return status ? : size; | |
338 | } | |
6beac9d1 | 339 | static DEVICE_ATTR_RW(active_low); |
0eb4c6c2 | 340 | |
ebbeba12 JH |
341 | static umode_t gpio_is_visible(struct kobject *kobj, struct attribute *attr, |
342 | int n) | |
343 | { | |
97cd738c | 344 | struct device *dev = kobj_to_dev(kobj); |
c43960fb JH |
345 | struct gpiod_data *data = dev_get_drvdata(dev); |
346 | struct gpio_desc *desc = data->desc; | |
ebbeba12 | 347 | umode_t mode = attr->mode; |
427fdeef | 348 | bool show_direction = data->direction_can_change; |
ebbeba12 JH |
349 | |
350 | if (attr == &dev_attr_direction.attr) { | |
351 | if (!show_direction) | |
352 | mode = 0; | |
353 | } else if (attr == &dev_attr_edge.attr) { | |
354 | if (gpiod_to_irq(desc) < 0) | |
355 | mode = 0; | |
356 | if (!show_direction && test_bit(FLAG_IS_OUT, &desc->flags)) | |
357 | mode = 0; | |
358 | } | |
359 | ||
360 | return mode; | |
361 | } | |
362 | ||
0915e6fe | 363 | static struct attribute *gpio_attrs[] = { |
ebbeba12 JH |
364 | &dev_attr_direction.attr, |
365 | &dev_attr_edge.attr, | |
0eb4c6c2 AC |
366 | &dev_attr_value.attr, |
367 | &dev_attr_active_low.attr, | |
368 | NULL, | |
369 | }; | |
ebbeba12 JH |
370 | |
371 | static const struct attribute_group gpio_group = { | |
372 | .attrs = gpio_attrs, | |
373 | .is_visible = gpio_is_visible, | |
374 | }; | |
375 | ||
376 | static const struct attribute_group *gpio_groups[] = { | |
377 | &gpio_group, | |
378 | NULL | |
379 | }; | |
0eb4c6c2 AC |
380 | |
381 | /* | |
382 | * /sys/class/gpio/gpiochipN/ | |
383 | * /base ... matching gpio_chip.base (N) | |
384 | * /label ... matching gpio_chip.label | |
385 | * /ngpio ... matching gpio_chip.ngpio | |
386 | */ | |
387 | ||
6beac9d1 | 388 | static ssize_t base_show(struct device *dev, |
0eb4c6c2 AC |
389 | struct device_attribute *attr, char *buf) |
390 | { | |
391 | const struct gpio_chip *chip = dev_get_drvdata(dev); | |
392 | ||
9e23bf6b | 393 | return sysfs_emit(buf, "%d\n", chip->base); |
0eb4c6c2 | 394 | } |
6beac9d1 | 395 | static DEVICE_ATTR_RO(base); |
0eb4c6c2 | 396 | |
6beac9d1 | 397 | static ssize_t label_show(struct device *dev, |
0eb4c6c2 AC |
398 | struct device_attribute *attr, char *buf) |
399 | { | |
400 | const struct gpio_chip *chip = dev_get_drvdata(dev); | |
401 | ||
9e23bf6b | 402 | return sysfs_emit(buf, "%s\n", chip->label ?: ""); |
0eb4c6c2 | 403 | } |
6beac9d1 | 404 | static DEVICE_ATTR_RO(label); |
0eb4c6c2 | 405 | |
6beac9d1 | 406 | static ssize_t ngpio_show(struct device *dev, |
0eb4c6c2 AC |
407 | struct device_attribute *attr, char *buf) |
408 | { | |
409 | const struct gpio_chip *chip = dev_get_drvdata(dev); | |
410 | ||
9e23bf6b | 411 | return sysfs_emit(buf, "%u\n", chip->ngpio); |
0eb4c6c2 | 412 | } |
6beac9d1 | 413 | static DEVICE_ATTR_RO(ngpio); |
0eb4c6c2 | 414 | |
121b6a79 | 415 | static struct attribute *gpiochip_attrs[] = { |
0eb4c6c2 AC |
416 | &dev_attr_base.attr, |
417 | &dev_attr_label.attr, | |
418 | &dev_attr_ngpio.attr, | |
419 | NULL, | |
420 | }; | |
121b6a79 | 421 | ATTRIBUTE_GROUPS(gpiochip); |
0eb4c6c2 AC |
422 | |
423 | /* | |
424 | * /sys/class/gpio/export ... write-only | |
425 | * integer N ... number of GPIO to export (full access) | |
426 | * /sys/class/gpio/unexport ... write-only | |
427 | * integer N ... number of GPIO to unexport | |
428 | */ | |
429 | static ssize_t export_store(struct class *class, | |
430 | struct class_attribute *attr, | |
431 | const char *buf, size_t len) | |
432 | { | |
433 | long gpio; | |
434 | struct gpio_desc *desc; | |
435 | int status; | |
23cf00dd MV |
436 | struct gpio_chip *gc; |
437 | int offset; | |
0eb4c6c2 AC |
438 | |
439 | status = kstrtol(buf, 0, &gpio); | |
440 | if (status < 0) | |
441 | goto done; | |
442 | ||
f13a0b0b | 443 | desc = gpio_to_desc(gpio); |
0eb4c6c2 AC |
444 | /* reject invalid GPIOs */ |
445 | if (!desc) { | |
446 | pr_warn("%s: invalid GPIO %ld\n", __func__, gpio); | |
447 | return -EINVAL; | |
448 | } | |
23cf00dd MV |
449 | gc = desc->gdev->chip; |
450 | offset = gpio_chip_hwgpio(desc); | |
451 | if (!gpiochip_line_is_valid(gc, offset)) { | |
452 | pr_warn("%s: GPIO %ld masked\n", __func__, gpio); | |
453 | return -EINVAL; | |
454 | } | |
0eb4c6c2 AC |
455 | |
456 | /* No extra locking here; FLAG_SYSFS just signifies that the | |
457 | * request and export were done by on behalf of userspace, so | |
458 | * they may be undone on its behalf too. | |
459 | */ | |
460 | ||
95a4eed7 AS |
461 | status = gpiod_request_user(desc, "sysfs"); |
462 | if (status) | |
0eb4c6c2 | 463 | goto done; |
e10f72bf AJ |
464 | |
465 | status = gpiod_set_transitory(desc, false); | |
466 | if (!status) { | |
467 | status = gpiod_export(desc, true); | |
468 | if (status < 0) | |
469 | gpiod_free(desc); | |
470 | else | |
471 | set_bit(FLAG_SYSFS, &desc->flags); | |
472 | } | |
0eb4c6c2 AC |
473 | |
474 | done: | |
475 | if (status) | |
476 | pr_debug("%s: status %d\n", __func__, status); | |
477 | return status ? : len; | |
478 | } | |
d83bb159 | 479 | static CLASS_ATTR_WO(export); |
0eb4c6c2 AC |
480 | |
481 | static ssize_t unexport_store(struct class *class, | |
482 | struct class_attribute *attr, | |
483 | const char *buf, size_t len) | |
484 | { | |
485 | long gpio; | |
486 | struct gpio_desc *desc; | |
487 | int status; | |
488 | ||
489 | status = kstrtol(buf, 0, &gpio); | |
490 | if (status < 0) | |
491 | goto done; | |
492 | ||
f13a0b0b | 493 | desc = gpio_to_desc(gpio); |
0eb4c6c2 AC |
494 | /* reject bogus commands (gpio_unexport ignores them) */ |
495 | if (!desc) { | |
496 | pr_warn("%s: invalid GPIO %ld\n", __func__, gpio); | |
497 | return -EINVAL; | |
498 | } | |
499 | ||
500 | status = -EINVAL; | |
501 | ||
502 | /* No extra locking here; FLAG_SYSFS just signifies that the | |
503 | * request and export were done by on behalf of userspace, so | |
504 | * they may be undone on its behalf too. | |
505 | */ | |
506 | if (test_and_clear_bit(FLAG_SYSFS, &desc->flags)) { | |
507 | status = 0; | |
508 | gpiod_free(desc); | |
509 | } | |
510 | done: | |
511 | if (status) | |
512 | pr_debug("%s: status %d\n", __func__, status); | |
513 | return status ? : len; | |
514 | } | |
d83bb159 | 515 | static CLASS_ATTR_WO(unexport); |
0eb4c6c2 | 516 | |
d83bb159 GKH |
517 | static struct attribute *gpio_class_attrs[] = { |
518 | &class_attr_export.attr, | |
519 | &class_attr_unexport.attr, | |
520 | NULL, | |
0eb4c6c2 | 521 | }; |
d83bb159 | 522 | ATTRIBUTE_GROUPS(gpio_class); |
0eb4c6c2 AC |
523 | |
524 | static struct class gpio_class = { | |
525 | .name = "gpio", | |
526 | .owner = THIS_MODULE, | |
527 | ||
d83bb159 | 528 | .class_groups = gpio_class_groups, |
0eb4c6c2 AC |
529 | }; |
530 | ||
531 | ||
532 | /** | |
533 | * gpiod_export - export a GPIO through sysfs | |
2d9d0519 TR |
534 | * @desc: GPIO to make available, already requested |
535 | * @direction_may_change: true if userspace may change GPIO direction | |
0eb4c6c2 AC |
536 | * Context: arch_initcall or later |
537 | * | |
538 | * When drivers want to make a GPIO accessible to userspace after they | |
539 | * have requested it -- perhaps while debugging, or as part of their | |
540 | * public interface -- they may use this routine. If the GPIO can | |
541 | * change direction (some can't) and the caller allows it, userspace | |
542 | * will see "direction" sysfs attribute which may be used to change | |
543 | * the gpio's direction. A "value" attribute will always be provided. | |
544 | * | |
545 | * Returns zero on success, else an error. | |
546 | */ | |
547 | int gpiod_export(struct gpio_desc *desc, bool direction_may_change) | |
548 | { | |
483d8211 | 549 | struct gpio_chip *chip; |
ff2b1359 | 550 | struct gpio_device *gdev; |
c43960fb | 551 | struct gpiod_data *data; |
0eb4c6c2 AC |
552 | unsigned long flags; |
553 | int status; | |
554 | const char *ioname = NULL; | |
555 | struct device *dev; | |
556 | int offset; | |
557 | ||
558 | /* can't export until sysfs is available ... */ | |
559 | if (!gpio_class.p) { | |
560 | pr_debug("%s: called too early!\n", __func__); | |
561 | return -ENOENT; | |
562 | } | |
563 | ||
564 | if (!desc) { | |
565 | pr_debug("%s: invalid gpio descriptor\n", __func__); | |
566 | return -EINVAL; | |
567 | } | |
568 | ||
fdeb8e15 LW |
569 | gdev = desc->gdev; |
570 | chip = gdev->chip; | |
483d8211 | 571 | |
0eb4c6c2 AC |
572 | mutex_lock(&sysfs_lock); |
573 | ||
483d8211 | 574 | /* check if chip is being removed */ |
afbc4f31 | 575 | if (!chip || !gdev->mockdev) { |
483d8211 | 576 | status = -ENODEV; |
c43960fb | 577 | goto err_unlock; |
483d8211 JH |
578 | } |
579 | ||
0eb4c6c2 AC |
580 | spin_lock_irqsave(&gpio_lock, flags); |
581 | if (!test_bit(FLAG_REQUESTED, &desc->flags) || | |
582 | test_bit(FLAG_EXPORT, &desc->flags)) { | |
583 | spin_unlock_irqrestore(&gpio_lock, flags); | |
584 | gpiod_dbg(desc, "%s: unavailable (requested=%d, exported=%d)\n", | |
585 | __func__, | |
586 | test_bit(FLAG_REQUESTED, &desc->flags), | |
587 | test_bit(FLAG_EXPORT, &desc->flags)); | |
588 | status = -EPERM; | |
c43960fb | 589 | goto err_unlock; |
0eb4c6c2 | 590 | } |
0eb4c6c2 AC |
591 | spin_unlock_irqrestore(&gpio_lock, flags); |
592 | ||
c43960fb JH |
593 | data = kzalloc(sizeof(*data), GFP_KERNEL); |
594 | if (!data) { | |
595 | status = -ENOMEM; | |
596 | goto err_unlock; | |
597 | } | |
598 | ||
599 | data->desc = desc; | |
6ffcb797 | 600 | mutex_init(&data->mutex); |
427fdeef JH |
601 | if (chip->direction_input && chip->direction_output) |
602 | data->direction_can_change = direction_may_change; | |
603 | else | |
604 | data->direction_can_change = false; | |
c43960fb | 605 | |
0eb4c6c2 | 606 | offset = gpio_chip_hwgpio(desc); |
cecf58ab JH |
607 | if (chip->names && chip->names[offset]) |
608 | ioname = chip->names[offset]; | |
0eb4c6c2 | 609 | |
ff2b1359 | 610 | dev = device_create_with_groups(&gpio_class, &gdev->dev, |
c43960fb | 611 | MKDEV(0, 0), data, gpio_groups, |
0915e6fe JH |
612 | ioname ? ioname : "gpio%u", |
613 | desc_to_gpio(desc)); | |
0eb4c6c2 AC |
614 | if (IS_ERR(dev)) { |
615 | status = PTR_ERR(dev); | |
c43960fb | 616 | goto err_free_data; |
0eb4c6c2 AC |
617 | } |
618 | ||
0eb4c6c2 AC |
619 | set_bit(FLAG_EXPORT, &desc->flags); |
620 | mutex_unlock(&sysfs_lock); | |
621 | return 0; | |
622 | ||
c43960fb JH |
623 | err_free_data: |
624 | kfree(data); | |
625 | err_unlock: | |
0eb4c6c2 AC |
626 | mutex_unlock(&sysfs_lock); |
627 | gpiod_dbg(desc, "%s: status %d\n", __func__, status); | |
628 | return status; | |
629 | } | |
630 | EXPORT_SYMBOL_GPL(gpiod_export); | |
631 | ||
c43960fb | 632 | static int match_export(struct device *dev, const void *desc) |
0eb4c6c2 | 633 | { |
c43960fb JH |
634 | struct gpiod_data *data = dev_get_drvdata(dev); |
635 | ||
636 | return data->desc == desc; | |
0eb4c6c2 AC |
637 | } |
638 | ||
639 | /** | |
640 | * gpiod_export_link - create a sysfs link to an exported GPIO node | |
641 | * @dev: device under which to create symlink | |
642 | * @name: name of the symlink | |
2d9d0519 | 643 | * @desc: GPIO to create symlink to, already exported |
0eb4c6c2 AC |
644 | * |
645 | * Set up a symlink from /sys/.../dev/name to /sys/class/gpio/gpioN | |
646 | * node. Caller is responsible for unlinking. | |
647 | * | |
648 | * Returns zero on success, else an error. | |
649 | */ | |
650 | int gpiod_export_link(struct device *dev, const char *name, | |
651 | struct gpio_desc *desc) | |
652 | { | |
56d30ec1 JH |
653 | struct device *cdev; |
654 | int ret; | |
0eb4c6c2 AC |
655 | |
656 | if (!desc) { | |
657 | pr_warn("%s: invalid GPIO\n", __func__); | |
658 | return -EINVAL; | |
659 | } | |
660 | ||
56d30ec1 JH |
661 | cdev = class_find_device(&gpio_class, NULL, desc, match_export); |
662 | if (!cdev) | |
663 | return -ENODEV; | |
0eb4c6c2 | 664 | |
56d30ec1 JH |
665 | ret = sysfs_create_link(&dev->kobj, &cdev->kobj, name); |
666 | put_device(cdev); | |
0eb4c6c2 | 667 | |
56d30ec1 | 668 | return ret; |
0eb4c6c2 AC |
669 | } |
670 | EXPORT_SYMBOL_GPL(gpiod_export_link); | |
671 | ||
0eb4c6c2 | 672 | /** |
31963eb0 | 673 | * gpiod_unexport - reverse effect of gpiod_export() |
2d9d0519 | 674 | * @desc: GPIO to make unavailable |
0eb4c6c2 | 675 | * |
31963eb0 | 676 | * This is implicit on gpiod_free(). |
0eb4c6c2 AC |
677 | */ |
678 | void gpiod_unexport(struct gpio_desc *desc) | |
679 | { | |
72eba6f6 JH |
680 | struct gpiod_data *data; |
681 | struct device *dev; | |
0eb4c6c2 AC |
682 | |
683 | if (!desc) { | |
684 | pr_warn("%s: invalid GPIO\n", __func__); | |
685 | return; | |
686 | } | |
687 | ||
688 | mutex_lock(&sysfs_lock); | |
689 | ||
72eba6f6 JH |
690 | if (!test_bit(FLAG_EXPORT, &desc->flags)) |
691 | goto err_unlock; | |
0eb4c6c2 | 692 | |
72eba6f6 JH |
693 | dev = class_find_device(&gpio_class, NULL, desc, match_export); |
694 | if (!dev) | |
695 | goto err_unlock; | |
696 | ||
697 | data = dev_get_drvdata(dev); | |
698 | ||
72eba6f6 JH |
699 | clear_bit(FLAG_EXPORT, &desc->flags); |
700 | ||
701 | device_unregister(dev); | |
702 | ||
703 | /* | |
704 | * Release irq after deregistration to prevent race with edge_store. | |
705 | */ | |
cef1717b | 706 | if (data->irq_flags) |
72eba6f6 | 707 | gpio_sysfs_free_irq(dev); |
0eb4c6c2 AC |
708 | |
709 | mutex_unlock(&sysfs_lock); | |
710 | ||
72eba6f6 JH |
711 | put_device(dev); |
712 | kfree(data); | |
0eb4c6c2 | 713 | |
72eba6f6 JH |
714 | return; |
715 | ||
716 | err_unlock: | |
717 | mutex_unlock(&sysfs_lock); | |
0eb4c6c2 AC |
718 | } |
719 | EXPORT_SYMBOL_GPL(gpiod_unexport); | |
720 | ||
afbc4f31 | 721 | int gpiochip_sysfs_register(struct gpio_device *gdev) |
0eb4c6c2 | 722 | { |
0eb4c6c2 | 723 | struct device *dev; |
d27c1728 | 724 | struct device *parent; |
afbc4f31 | 725 | struct gpio_chip *chip = gdev->chip; |
0eb4c6c2 | 726 | |
426577bd JH |
727 | /* |
728 | * Many systems add gpio chips for SOC support very early, | |
0eb4c6c2 | 729 | * before driver model support is available. In those cases we |
426577bd | 730 | * register later, in gpiolib_sysfs_init() ... here we just |
0eb4c6c2 AC |
731 | * verify that _some_ field of gpio_class got initialized. |
732 | */ | |
733 | if (!gpio_class.p) | |
734 | return 0; | |
735 | ||
d27c1728 BJZ |
736 | /* |
737 | * For sysfs backward compatibility we need to preserve this | |
738 | * preferred parenting to the gpio_chip parent field, if set. | |
739 | */ | |
740 | if (chip->parent) | |
741 | parent = chip->parent; | |
742 | else | |
743 | parent = &gdev->dev; | |
744 | ||
0eb4c6c2 | 745 | /* use chip->base for the ID; it's already known to be unique */ |
ddd8891e GU |
746 | dev = device_create_with_groups(&gpio_class, parent, MKDEV(0, 0), chip, |
747 | gpiochip_groups, GPIOCHIP_NAME "%d", | |
748 | chip->base); | |
121b6a79 | 749 | if (IS_ERR(dev)) |
6a4b6b0a | 750 | return PTR_ERR(dev); |
3ff74be5 JH |
751 | |
752 | mutex_lock(&sysfs_lock); | |
afbc4f31 | 753 | gdev->mockdev = dev; |
0eb4c6c2 AC |
754 | mutex_unlock(&sysfs_lock); |
755 | ||
6a4b6b0a | 756 | return 0; |
0eb4c6c2 AC |
757 | } |
758 | ||
afbc4f31 | 759 | void gpiochip_sysfs_unregister(struct gpio_device *gdev) |
0eb4c6c2 | 760 | { |
483d8211 | 761 | struct gpio_desc *desc; |
afbc4f31 | 762 | struct gpio_chip *chip = gdev->chip; |
0eb4c6c2 | 763 | |
afbc4f31 | 764 | if (!gdev->mockdev) |
6a4b6b0a | 765 | return; |
0eb4c6c2 | 766 | |
afbc4f31 | 767 | device_unregister(gdev->mockdev); |
6a4b6b0a JH |
768 | |
769 | /* prevent further gpiod exports */ | |
770 | mutex_lock(&sysfs_lock); | |
afbc4f31 | 771 | gdev->mockdev = NULL; |
6a4b6b0a | 772 | mutex_unlock(&sysfs_lock); |
483d8211 JH |
773 | |
774 | /* unregister gpiod class devices owned by sysfs */ | |
57017edd | 775 | for_each_gpio_desc_with_flag(chip, desc, FLAG_SYSFS) |
80c78fbe | 776 | gpiod_free(desc); |
0eb4c6c2 AC |
777 | } |
778 | ||
779 | static int __init gpiolib_sysfs_init(void) | |
780 | { | |
781 | int status; | |
782 | unsigned long flags; | |
ff2b1359 | 783 | struct gpio_device *gdev; |
0eb4c6c2 AC |
784 | |
785 | status = class_register(&gpio_class); | |
786 | if (status < 0) | |
787 | return status; | |
788 | ||
789 | /* Scan and register the gpio_chips which registered very | |
790 | * early (e.g. before the class_register above was called). | |
791 | * | |
792 | * We run before arch_initcall() so chip->dev nodes can have | |
793 | * registered, and so arch_initcall() can always gpio_export(). | |
794 | */ | |
795 | spin_lock_irqsave(&gpio_lock, flags); | |
ff2b1359 | 796 | list_for_each_entry(gdev, &gpio_devices, list) { |
afbc4f31 | 797 | if (gdev->mockdev) |
0eb4c6c2 AC |
798 | continue; |
799 | ||
14141a93 | 800 | /* |
426577bd JH |
801 | * TODO we yield gpio_lock here because |
802 | * gpiochip_sysfs_register() acquires a mutex. This is unsafe | |
803 | * and needs to be fixed. | |
14141a93 AC |
804 | * |
805 | * Also it would be nice to use gpiochip_find() here so we | |
806 | * can keep gpio_chips local to gpiolib.c, but the yield of | |
807 | * gpio_lock prevents us from doing this. | |
808 | */ | |
0eb4c6c2 | 809 | spin_unlock_irqrestore(&gpio_lock, flags); |
afbc4f31 | 810 | status = gpiochip_sysfs_register(gdev); |
0eb4c6c2 AC |
811 | spin_lock_irqsave(&gpio_lock, flags); |
812 | } | |
813 | spin_unlock_irqrestore(&gpio_lock, flags); | |
814 | ||
0eb4c6c2 AC |
815 | return status; |
816 | } | |
817 | postcore_initcall(gpiolib_sysfs_init); |