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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 | |
cef1717b JH |
16 | #define GPIO_IRQF_TRIGGER_FALLING BIT(0) |
17 | #define GPIO_IRQF_TRIGGER_RISING BIT(1) | |
18 | #define GPIO_IRQF_TRIGGER_BOTH (GPIO_IRQF_TRIGGER_FALLING | \ | |
19 | GPIO_IRQF_TRIGGER_RISING) | |
20 | ||
c43960fb JH |
21 | struct gpiod_data { |
22 | struct gpio_desc *desc; | |
6ffcb797 JH |
23 | |
24 | struct mutex mutex; | |
a08f5c21 | 25 | struct kernfs_node *value_kn; |
2ec74a95 | 26 | int irq; |
cef1717b | 27 | unsigned char irq_flags; |
427fdeef JH |
28 | |
29 | bool direction_can_change; | |
c43960fb JH |
30 | }; |
31 | ||
6ffcb797 JH |
32 | /* |
33 | * Lock to serialise gpiod export and unexport, and prevent re-export of | |
34 | * gpiod whose chip is being unregistered. | |
0eb4c6c2 AC |
35 | */ |
36 | static DEFINE_MUTEX(sysfs_lock); | |
37 | ||
38 | /* | |
39 | * /sys/class/gpio/gpioN... only for GPIOs that are exported | |
40 | * /direction | |
41 | * * MAY BE OMITTED if kernel won't allow direction changes | |
42 | * * is read/write as "in" or "out" | |
43 | * * may also be written as "high" or "low", initializing | |
44 | * output value as specified ("out" implies "low") | |
45 | * /value | |
46 | * * always readable, subject to hardware behavior | |
47 | * * may be writable, as zero/nonzero | |
48 | * /edge | |
49 | * * configures behavior of poll(2) on /value | |
50 | * * available only if pin can generate IRQs on input | |
51 | * * is read/write as "none", "falling", "rising", or "both" | |
52 | * /active_low | |
53 | * * configures polarity of /value | |
54 | * * is read/write as zero/nonzero | |
55 | * * also affects existing and subsequent "falling" and "rising" | |
56 | * /edge configuration | |
57 | */ | |
58 | ||
6beac9d1 | 59 | static ssize_t direction_show(struct device *dev, |
0eb4c6c2 AC |
60 | struct device_attribute *attr, char *buf) |
61 | { | |
c43960fb JH |
62 | struct gpiod_data *data = dev_get_drvdata(dev); |
63 | struct gpio_desc *desc = data->desc; | |
0eb4c6c2 AC |
64 | ssize_t status; |
65 | ||
6ffcb797 | 66 | mutex_lock(&data->mutex); |
0eb4c6c2 | 67 | |
f0b7866a JH |
68 | gpiod_get_direction(desc); |
69 | status = sprintf(buf, "%s\n", | |
0eb4c6c2 AC |
70 | test_bit(FLAG_IS_OUT, &desc->flags) |
71 | ? "out" : "in"); | |
0eb4c6c2 | 72 | |
6ffcb797 JH |
73 | mutex_unlock(&data->mutex); |
74 | ||
0eb4c6c2 AC |
75 | return status; |
76 | } | |
77 | ||
6beac9d1 | 78 | static ssize_t direction_store(struct device *dev, |
0eb4c6c2 AC |
79 | struct device_attribute *attr, const char *buf, size_t size) |
80 | { | |
c43960fb JH |
81 | struct gpiod_data *data = dev_get_drvdata(dev); |
82 | struct gpio_desc *desc = data->desc; | |
0eb4c6c2 AC |
83 | ssize_t status; |
84 | ||
6ffcb797 | 85 | mutex_lock(&data->mutex); |
0eb4c6c2 | 86 | |
f0b7866a | 87 | if (sysfs_streq(buf, "high")) |
0eb4c6c2 AC |
88 | status = gpiod_direction_output_raw(desc, 1); |
89 | else if (sysfs_streq(buf, "out") || sysfs_streq(buf, "low")) | |
90 | status = gpiod_direction_output_raw(desc, 0); | |
91 | else if (sysfs_streq(buf, "in")) | |
92 | status = gpiod_direction_input(desc); | |
93 | else | |
94 | status = -EINVAL; | |
95 | ||
6ffcb797 JH |
96 | mutex_unlock(&data->mutex); |
97 | ||
0eb4c6c2 AC |
98 | return status ? : size; |
99 | } | |
6beac9d1 | 100 | static DEVICE_ATTR_RW(direction); |
0eb4c6c2 | 101 | |
6beac9d1 | 102 | static ssize_t value_show(struct device *dev, |
0eb4c6c2 AC |
103 | struct device_attribute *attr, char *buf) |
104 | { | |
c43960fb JH |
105 | struct gpiod_data *data = dev_get_drvdata(dev); |
106 | struct gpio_desc *desc = data->desc; | |
0eb4c6c2 AC |
107 | ssize_t status; |
108 | ||
6ffcb797 | 109 | mutex_lock(&data->mutex); |
0eb4c6c2 | 110 | |
9295c012 CL |
111 | status = gpiod_get_value_cansleep(desc); |
112 | if (status < 0) | |
113 | goto err; | |
0eb4c6c2 | 114 | |
7a94b88c CL |
115 | buf[0] = '0' + status; |
116 | buf[1] = '\n'; | |
117 | status = 2; | |
9295c012 | 118 | err: |
6ffcb797 JH |
119 | mutex_unlock(&data->mutex); |
120 | ||
0eb4c6c2 AC |
121 | return status; |
122 | } | |
123 | ||
6beac9d1 | 124 | static ssize_t value_store(struct device *dev, |
0eb4c6c2 AC |
125 | struct device_attribute *attr, const char *buf, size_t size) |
126 | { | |
c43960fb JH |
127 | struct gpiod_data *data = dev_get_drvdata(dev); |
128 | struct gpio_desc *desc = data->desc; | |
1efba35a | 129 | ssize_t status = 0; |
0eb4c6c2 | 130 | |
6ffcb797 | 131 | mutex_lock(&data->mutex); |
0eb4c6c2 | 132 | |
f0b7866a | 133 | if (!test_bit(FLAG_IS_OUT, &desc->flags)) { |
0eb4c6c2 | 134 | status = -EPERM; |
f0b7866a | 135 | } else { |
0eb4c6c2 AC |
136 | long value; |
137 | ||
1efba35a CL |
138 | if (size <= 2 && isdigit(buf[0]) && |
139 | (size == 1 || buf[1] == '\n')) | |
140 | value = buf[0] - '0'; | |
141 | else | |
142 | status = kstrtol(buf, 0, &value); | |
0eb4c6c2 AC |
143 | if (status == 0) { |
144 | gpiod_set_value_cansleep(desc, value); | |
145 | status = size; | |
146 | } | |
147 | } | |
148 | ||
6ffcb797 JH |
149 | mutex_unlock(&data->mutex); |
150 | ||
0eb4c6c2 AC |
151 | return status; |
152 | } | |
7fda9100 | 153 | static DEVICE_ATTR_PREALLOC(value, S_IWUSR | S_IRUGO, value_show, value_store); |
0eb4c6c2 AC |
154 | |
155 | static irqreturn_t gpio_sysfs_irq(int irq, void *priv) | |
156 | { | |
a08f5c21 JH |
157 | struct gpiod_data *data = priv; |
158 | ||
159 | sysfs_notify_dirent(data->value_kn); | |
0eb4c6c2 | 160 | |
0eb4c6c2 AC |
161 | return IRQ_HANDLED; |
162 | } | |
163 | ||
6ffcb797 | 164 | /* Caller holds gpiod-data mutex. */ |
cef1717b | 165 | static int gpio_sysfs_request_irq(struct device *dev, unsigned char flags) |
0eb4c6c2 | 166 | { |
0f628508 JH |
167 | struct gpiod_data *data = dev_get_drvdata(dev); |
168 | struct gpio_desc *desc = data->desc; | |
0eb4c6c2 | 169 | unsigned long irq_flags; |
2ec74a95 | 170 | int ret; |
0eb4c6c2 | 171 | |
2ec74a95 JH |
172 | data->irq = gpiod_to_irq(desc); |
173 | if (data->irq < 0) | |
0eb4c6c2 AC |
174 | return -EIO; |
175 | ||
2ec74a95 JH |
176 | data->value_kn = sysfs_get_dirent(dev->kobj.sd, "value"); |
177 | if (!data->value_kn) | |
178 | return -ENODEV; | |
0eb4c6c2 AC |
179 | |
180 | irq_flags = IRQF_SHARED; | |
cef1717b | 181 | if (flags & GPIO_IRQF_TRIGGER_FALLING) |
0eb4c6c2 AC |
182 | irq_flags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ? |
183 | IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING; | |
cef1717b | 184 | if (flags & GPIO_IRQF_TRIGGER_RISING) |
0eb4c6c2 AC |
185 | irq_flags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ? |
186 | IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING; | |
187 | ||
52176d0d JH |
188 | /* |
189 | * FIXME: This should be done in the irq_request_resources callback | |
190 | * when the irq is requested, but a few drivers currently fail | |
191 | * to do so. | |
192 | * | |
193 | * Remove this redundant call (along with the corresponding | |
194 | * unlock) when those drivers have been fixed. | |
195 | */ | |
fdeb8e15 | 196 | ret = gpiochip_lock_as_irq(desc->gdev->chip, gpio_chip_hwgpio(desc)); |
0eb4c6c2 | 197 | if (ret < 0) |
2ec74a95 | 198 | goto err_put_kn; |
0eb4c6c2 | 199 | |
2ec74a95 | 200 | ret = request_any_context_irq(data->irq, gpio_sysfs_irq, irq_flags, |
a08f5c21 | 201 | "gpiolib", data); |
52176d0d JH |
202 | if (ret < 0) |
203 | goto err_unlock; | |
0eb4c6c2 | 204 | |
cef1717b | 205 | data->irq_flags = flags; |
2ec74a95 | 206 | |
0eb4c6c2 AC |
207 | return 0; |
208 | ||
52176d0d | 209 | err_unlock: |
fdeb8e15 | 210 | gpiochip_unlock_as_irq(desc->gdev->chip, gpio_chip_hwgpio(desc)); |
2ec74a95 JH |
211 | err_put_kn: |
212 | sysfs_put(data->value_kn); | |
213 | ||
0eb4c6c2 AC |
214 | return ret; |
215 | } | |
216 | ||
6ffcb797 JH |
217 | /* |
218 | * Caller holds gpiod-data mutex (unless called after class-device | |
219 | * deregistration). | |
220 | */ | |
2ec74a95 JH |
221 | static void gpio_sysfs_free_irq(struct device *dev) |
222 | { | |
223 | struct gpiod_data *data = dev_get_drvdata(dev); | |
224 | struct gpio_desc *desc = data->desc; | |
225 | ||
cef1717b | 226 | data->irq_flags = 0; |
2ec74a95 | 227 | free_irq(data->irq, data); |
fdeb8e15 | 228 | gpiochip_unlock_as_irq(desc->gdev->chip, gpio_chip_hwgpio(desc)); |
2ec74a95 JH |
229 | sysfs_put(data->value_kn); |
230 | } | |
231 | ||
0eb4c6c2 AC |
232 | static const struct { |
233 | const char *name; | |
cef1717b | 234 | unsigned char flags; |
0eb4c6c2 AC |
235 | } trigger_types[] = { |
236 | { "none", 0 }, | |
cef1717b JH |
237 | { "falling", GPIO_IRQF_TRIGGER_FALLING }, |
238 | { "rising", GPIO_IRQF_TRIGGER_RISING }, | |
239 | { "both", GPIO_IRQF_TRIGGER_BOTH }, | |
0eb4c6c2 AC |
240 | }; |
241 | ||
6beac9d1 | 242 | static ssize_t edge_show(struct device *dev, |
0eb4c6c2 AC |
243 | struct device_attribute *attr, char *buf) |
244 | { | |
c43960fb | 245 | struct gpiod_data *data = dev_get_drvdata(dev); |
f0b7866a JH |
246 | ssize_t status = 0; |
247 | int i; | |
0eb4c6c2 | 248 | |
6ffcb797 | 249 | mutex_lock(&data->mutex); |
0eb4c6c2 | 250 | |
f0b7866a | 251 | for (i = 0; i < ARRAY_SIZE(trigger_types); i++) { |
cef1717b | 252 | if (data->irq_flags == trigger_types[i].flags) { |
f0b7866a JH |
253 | status = sprintf(buf, "%s\n", trigger_types[i].name); |
254 | break; | |
255 | } | |
0eb4c6c2 AC |
256 | } |
257 | ||
6ffcb797 JH |
258 | mutex_unlock(&data->mutex); |
259 | ||
0eb4c6c2 AC |
260 | return status; |
261 | } | |
262 | ||
6beac9d1 | 263 | static ssize_t edge_store(struct device *dev, |
0eb4c6c2 AC |
264 | struct device_attribute *attr, const char *buf, size_t size) |
265 | { | |
b91e1807 | 266 | struct gpiod_data *data = dev_get_drvdata(dev); |
cef1717b | 267 | unsigned char flags; |
2ec74a95 | 268 | ssize_t status = size; |
e4339ce3 | 269 | int i; |
0eb4c6c2 | 270 | |
e4339ce3 | 271 | for (i = 0; i < ARRAY_SIZE(trigger_types); i++) { |
0eb4c6c2 | 272 | if (sysfs_streq(trigger_types[i].name, buf)) |
e4339ce3 JH |
273 | break; |
274 | } | |
275 | ||
276 | if (i == ARRAY_SIZE(trigger_types)) | |
277 | return -EINVAL; | |
0eb4c6c2 | 278 | |
b91e1807 JH |
279 | flags = trigger_types[i].flags; |
280 | ||
6ffcb797 | 281 | mutex_lock(&data->mutex); |
0eb4c6c2 | 282 | |
cef1717b | 283 | if (flags == data->irq_flags) { |
b91e1807 JH |
284 | status = size; |
285 | goto out_unlock; | |
286 | } | |
287 | ||
cef1717b | 288 | if (data->irq_flags) |
2ec74a95 JH |
289 | gpio_sysfs_free_irq(dev); |
290 | ||
291 | if (flags) { | |
292 | status = gpio_sysfs_request_irq(dev, flags); | |
293 | if (!status) | |
294 | status = size; | |
295 | } | |
0eb4c6c2 | 296 | |
b91e1807 | 297 | out_unlock: |
6ffcb797 | 298 | mutex_unlock(&data->mutex); |
0eb4c6c2 AC |
299 | |
300 | return status; | |
301 | } | |
6beac9d1 | 302 | static DEVICE_ATTR_RW(edge); |
0eb4c6c2 | 303 | |
6ffcb797 | 304 | /* Caller holds gpiod-data mutex. */ |
2f323b85 | 305 | static int gpio_sysfs_set_active_low(struct device *dev, int value) |
0eb4c6c2 | 306 | { |
0f628508 JH |
307 | struct gpiod_data *data = dev_get_drvdata(dev); |
308 | struct gpio_desc *desc = data->desc; | |
0eb4c6c2 | 309 | int status = 0; |
cef1717b | 310 | unsigned int flags = data->irq_flags; |
0eb4c6c2 AC |
311 | |
312 | if (!!test_bit(FLAG_ACTIVE_LOW, &desc->flags) == !!value) | |
313 | return 0; | |
314 | ||
315 | if (value) | |
316 | set_bit(FLAG_ACTIVE_LOW, &desc->flags); | |
317 | else | |
318 | clear_bit(FLAG_ACTIVE_LOW, &desc->flags); | |
319 | ||
320 | /* reconfigure poll(2) support if enabled on one edge only */ | |
cef1717b JH |
321 | if (flags == GPIO_IRQF_TRIGGER_FALLING || |
322 | flags == GPIO_IRQF_TRIGGER_RISING) { | |
2ec74a95 | 323 | gpio_sysfs_free_irq(dev); |
cef1717b | 324 | status = gpio_sysfs_request_irq(dev, flags); |
0eb4c6c2 AC |
325 | } |
326 | ||
327 | return status; | |
328 | } | |
329 | ||
6beac9d1 | 330 | static ssize_t active_low_show(struct device *dev, |
0eb4c6c2 AC |
331 | struct device_attribute *attr, char *buf) |
332 | { | |
c43960fb JH |
333 | struct gpiod_data *data = dev_get_drvdata(dev); |
334 | struct gpio_desc *desc = data->desc; | |
0eb4c6c2 AC |
335 | ssize_t status; |
336 | ||
6ffcb797 | 337 | mutex_lock(&data->mutex); |
0eb4c6c2 | 338 | |
f0b7866a | 339 | status = sprintf(buf, "%d\n", |
0eb4c6c2 AC |
340 | !!test_bit(FLAG_ACTIVE_LOW, &desc->flags)); |
341 | ||
6ffcb797 | 342 | mutex_unlock(&data->mutex); |
0eb4c6c2 AC |
343 | |
344 | return status; | |
345 | } | |
346 | ||
6beac9d1 | 347 | static ssize_t active_low_store(struct device *dev, |
0eb4c6c2 AC |
348 | struct device_attribute *attr, const char *buf, size_t size) |
349 | { | |
6ffcb797 | 350 | struct gpiod_data *data = dev_get_drvdata(dev); |
0eb4c6c2 | 351 | ssize_t status; |
f0b7866a | 352 | long value; |
0eb4c6c2 | 353 | |
6ffcb797 | 354 | mutex_lock(&data->mutex); |
0eb4c6c2 | 355 | |
f0b7866a JH |
356 | status = kstrtol(buf, 0, &value); |
357 | if (status == 0) | |
2f323b85 | 358 | status = gpio_sysfs_set_active_low(dev, value); |
0eb4c6c2 | 359 | |
6ffcb797 | 360 | mutex_unlock(&data->mutex); |
0eb4c6c2 AC |
361 | |
362 | return status ? : size; | |
363 | } | |
6beac9d1 | 364 | static DEVICE_ATTR_RW(active_low); |
0eb4c6c2 | 365 | |
ebbeba12 JH |
366 | static umode_t gpio_is_visible(struct kobject *kobj, struct attribute *attr, |
367 | int n) | |
368 | { | |
97cd738c | 369 | struct device *dev = kobj_to_dev(kobj); |
c43960fb JH |
370 | struct gpiod_data *data = dev_get_drvdata(dev); |
371 | struct gpio_desc *desc = data->desc; | |
ebbeba12 | 372 | umode_t mode = attr->mode; |
427fdeef | 373 | bool show_direction = data->direction_can_change; |
ebbeba12 JH |
374 | |
375 | if (attr == &dev_attr_direction.attr) { | |
376 | if (!show_direction) | |
377 | mode = 0; | |
378 | } else if (attr == &dev_attr_edge.attr) { | |
379 | if (gpiod_to_irq(desc) < 0) | |
380 | mode = 0; | |
381 | if (!show_direction && test_bit(FLAG_IS_OUT, &desc->flags)) | |
382 | mode = 0; | |
383 | } | |
384 | ||
385 | return mode; | |
386 | } | |
387 | ||
0915e6fe | 388 | static struct attribute *gpio_attrs[] = { |
ebbeba12 JH |
389 | &dev_attr_direction.attr, |
390 | &dev_attr_edge.attr, | |
0eb4c6c2 AC |
391 | &dev_attr_value.attr, |
392 | &dev_attr_active_low.attr, | |
393 | NULL, | |
394 | }; | |
ebbeba12 JH |
395 | |
396 | static const struct attribute_group gpio_group = { | |
397 | .attrs = gpio_attrs, | |
398 | .is_visible = gpio_is_visible, | |
399 | }; | |
400 | ||
401 | static const struct attribute_group *gpio_groups[] = { | |
402 | &gpio_group, | |
403 | NULL | |
404 | }; | |
0eb4c6c2 AC |
405 | |
406 | /* | |
407 | * /sys/class/gpio/gpiochipN/ | |
408 | * /base ... matching gpio_chip.base (N) | |
409 | * /label ... matching gpio_chip.label | |
410 | * /ngpio ... matching gpio_chip.ngpio | |
411 | */ | |
412 | ||
6beac9d1 | 413 | static ssize_t base_show(struct device *dev, |
0eb4c6c2 AC |
414 | struct device_attribute *attr, char *buf) |
415 | { | |
416 | const struct gpio_chip *chip = dev_get_drvdata(dev); | |
417 | ||
418 | return sprintf(buf, "%d\n", chip->base); | |
419 | } | |
6beac9d1 | 420 | static DEVICE_ATTR_RO(base); |
0eb4c6c2 | 421 | |
6beac9d1 | 422 | static ssize_t label_show(struct device *dev, |
0eb4c6c2 AC |
423 | struct device_attribute *attr, char *buf) |
424 | { | |
425 | const struct gpio_chip *chip = dev_get_drvdata(dev); | |
426 | ||
427 | return sprintf(buf, "%s\n", chip->label ? : ""); | |
428 | } | |
6beac9d1 | 429 | static DEVICE_ATTR_RO(label); |
0eb4c6c2 | 430 | |
6beac9d1 | 431 | static ssize_t ngpio_show(struct device *dev, |
0eb4c6c2 AC |
432 | struct device_attribute *attr, char *buf) |
433 | { | |
434 | const struct gpio_chip *chip = dev_get_drvdata(dev); | |
435 | ||
436 | return sprintf(buf, "%u\n", chip->ngpio); | |
437 | } | |
6beac9d1 | 438 | static DEVICE_ATTR_RO(ngpio); |
0eb4c6c2 | 439 | |
121b6a79 | 440 | static struct attribute *gpiochip_attrs[] = { |
0eb4c6c2 AC |
441 | &dev_attr_base.attr, |
442 | &dev_attr_label.attr, | |
443 | &dev_attr_ngpio.attr, | |
444 | NULL, | |
445 | }; | |
121b6a79 | 446 | ATTRIBUTE_GROUPS(gpiochip); |
0eb4c6c2 AC |
447 | |
448 | /* | |
449 | * /sys/class/gpio/export ... write-only | |
450 | * integer N ... number of GPIO to export (full access) | |
451 | * /sys/class/gpio/unexport ... write-only | |
452 | * integer N ... number of GPIO to unexport | |
453 | */ | |
454 | static ssize_t export_store(struct class *class, | |
455 | struct class_attribute *attr, | |
456 | const char *buf, size_t len) | |
457 | { | |
458 | long gpio; | |
459 | struct gpio_desc *desc; | |
460 | int status; | |
461 | ||
462 | status = kstrtol(buf, 0, &gpio); | |
463 | if (status < 0) | |
464 | goto done; | |
465 | ||
f13a0b0b | 466 | desc = gpio_to_desc(gpio); |
0eb4c6c2 AC |
467 | /* reject invalid GPIOs */ |
468 | if (!desc) { | |
469 | pr_warn("%s: invalid GPIO %ld\n", __func__, gpio); | |
470 | return -EINVAL; | |
471 | } | |
472 | ||
473 | /* No extra locking here; FLAG_SYSFS just signifies that the | |
474 | * request and export were done by on behalf of userspace, so | |
475 | * they may be undone on its behalf too. | |
476 | */ | |
477 | ||
478 | status = gpiod_request(desc, "sysfs"); | |
8bbff39c | 479 | if (status) { |
0eb4c6c2 AC |
480 | if (status == -EPROBE_DEFER) |
481 | status = -ENODEV; | |
482 | goto done; | |
483 | } | |
e10f72bf AJ |
484 | |
485 | status = gpiod_set_transitory(desc, false); | |
486 | if (!status) { | |
487 | status = gpiod_export(desc, true); | |
488 | if (status < 0) | |
489 | gpiod_free(desc); | |
490 | else | |
491 | set_bit(FLAG_SYSFS, &desc->flags); | |
492 | } | |
0eb4c6c2 AC |
493 | |
494 | done: | |
495 | if (status) | |
496 | pr_debug("%s: status %d\n", __func__, status); | |
497 | return status ? : len; | |
498 | } | |
d83bb159 | 499 | static CLASS_ATTR_WO(export); |
0eb4c6c2 AC |
500 | |
501 | static ssize_t unexport_store(struct class *class, | |
502 | struct class_attribute *attr, | |
503 | const char *buf, size_t len) | |
504 | { | |
505 | long gpio; | |
506 | struct gpio_desc *desc; | |
507 | int status; | |
508 | ||
509 | status = kstrtol(buf, 0, &gpio); | |
510 | if (status < 0) | |
511 | goto done; | |
512 | ||
f13a0b0b | 513 | desc = gpio_to_desc(gpio); |
0eb4c6c2 AC |
514 | /* reject bogus commands (gpio_unexport ignores them) */ |
515 | if (!desc) { | |
516 | pr_warn("%s: invalid GPIO %ld\n", __func__, gpio); | |
517 | return -EINVAL; | |
518 | } | |
519 | ||
520 | status = -EINVAL; | |
521 | ||
522 | /* No extra locking here; FLAG_SYSFS just signifies that the | |
523 | * request and export were done by on behalf of userspace, so | |
524 | * they may be undone on its behalf too. | |
525 | */ | |
526 | if (test_and_clear_bit(FLAG_SYSFS, &desc->flags)) { | |
527 | status = 0; | |
528 | gpiod_free(desc); | |
529 | } | |
530 | done: | |
531 | if (status) | |
532 | pr_debug("%s: status %d\n", __func__, status); | |
533 | return status ? : len; | |
534 | } | |
d83bb159 | 535 | static CLASS_ATTR_WO(unexport); |
0eb4c6c2 | 536 | |
d83bb159 GKH |
537 | static struct attribute *gpio_class_attrs[] = { |
538 | &class_attr_export.attr, | |
539 | &class_attr_unexport.attr, | |
540 | NULL, | |
0eb4c6c2 | 541 | }; |
d83bb159 | 542 | ATTRIBUTE_GROUPS(gpio_class); |
0eb4c6c2 AC |
543 | |
544 | static struct class gpio_class = { | |
545 | .name = "gpio", | |
546 | .owner = THIS_MODULE, | |
547 | ||
d83bb159 | 548 | .class_groups = gpio_class_groups, |
0eb4c6c2 AC |
549 | }; |
550 | ||
551 | ||
552 | /** | |
553 | * gpiod_export - export a GPIO through sysfs | |
2d9d0519 TR |
554 | * @desc: GPIO to make available, already requested |
555 | * @direction_may_change: true if userspace may change GPIO direction | |
0eb4c6c2 AC |
556 | * Context: arch_initcall or later |
557 | * | |
558 | * When drivers want to make a GPIO accessible to userspace after they | |
559 | * have requested it -- perhaps while debugging, or as part of their | |
560 | * public interface -- they may use this routine. If the GPIO can | |
561 | * change direction (some can't) and the caller allows it, userspace | |
562 | * will see "direction" sysfs attribute which may be used to change | |
563 | * the gpio's direction. A "value" attribute will always be provided. | |
564 | * | |
565 | * Returns zero on success, else an error. | |
566 | */ | |
567 | int gpiod_export(struct gpio_desc *desc, bool direction_may_change) | |
568 | { | |
483d8211 | 569 | struct gpio_chip *chip; |
ff2b1359 | 570 | struct gpio_device *gdev; |
c43960fb | 571 | struct gpiod_data *data; |
0eb4c6c2 AC |
572 | unsigned long flags; |
573 | int status; | |
574 | const char *ioname = NULL; | |
575 | struct device *dev; | |
576 | int offset; | |
577 | ||
578 | /* can't export until sysfs is available ... */ | |
579 | if (!gpio_class.p) { | |
580 | pr_debug("%s: called too early!\n", __func__); | |
581 | return -ENOENT; | |
582 | } | |
583 | ||
584 | if (!desc) { | |
585 | pr_debug("%s: invalid gpio descriptor\n", __func__); | |
586 | return -EINVAL; | |
587 | } | |
588 | ||
fdeb8e15 LW |
589 | gdev = desc->gdev; |
590 | chip = gdev->chip; | |
483d8211 | 591 | |
0eb4c6c2 AC |
592 | mutex_lock(&sysfs_lock); |
593 | ||
483d8211 | 594 | /* check if chip is being removed */ |
afbc4f31 | 595 | if (!chip || !gdev->mockdev) { |
483d8211 | 596 | status = -ENODEV; |
c43960fb | 597 | goto err_unlock; |
483d8211 JH |
598 | } |
599 | ||
0eb4c6c2 AC |
600 | spin_lock_irqsave(&gpio_lock, flags); |
601 | if (!test_bit(FLAG_REQUESTED, &desc->flags) || | |
602 | test_bit(FLAG_EXPORT, &desc->flags)) { | |
603 | spin_unlock_irqrestore(&gpio_lock, flags); | |
604 | gpiod_dbg(desc, "%s: unavailable (requested=%d, exported=%d)\n", | |
605 | __func__, | |
606 | test_bit(FLAG_REQUESTED, &desc->flags), | |
607 | test_bit(FLAG_EXPORT, &desc->flags)); | |
608 | status = -EPERM; | |
c43960fb | 609 | goto err_unlock; |
0eb4c6c2 | 610 | } |
0eb4c6c2 AC |
611 | spin_unlock_irqrestore(&gpio_lock, flags); |
612 | ||
c43960fb JH |
613 | data = kzalloc(sizeof(*data), GFP_KERNEL); |
614 | if (!data) { | |
615 | status = -ENOMEM; | |
616 | goto err_unlock; | |
617 | } | |
618 | ||
619 | data->desc = desc; | |
6ffcb797 | 620 | mutex_init(&data->mutex); |
427fdeef JH |
621 | if (chip->direction_input && chip->direction_output) |
622 | data->direction_can_change = direction_may_change; | |
623 | else | |
624 | data->direction_can_change = false; | |
c43960fb | 625 | |
0eb4c6c2 | 626 | offset = gpio_chip_hwgpio(desc); |
cecf58ab JH |
627 | if (chip->names && chip->names[offset]) |
628 | ioname = chip->names[offset]; | |
0eb4c6c2 | 629 | |
ff2b1359 | 630 | dev = device_create_with_groups(&gpio_class, &gdev->dev, |
c43960fb | 631 | MKDEV(0, 0), data, gpio_groups, |
0915e6fe JH |
632 | ioname ? ioname : "gpio%u", |
633 | desc_to_gpio(desc)); | |
0eb4c6c2 AC |
634 | if (IS_ERR(dev)) { |
635 | status = PTR_ERR(dev); | |
c43960fb | 636 | goto err_free_data; |
0eb4c6c2 AC |
637 | } |
638 | ||
0eb4c6c2 AC |
639 | set_bit(FLAG_EXPORT, &desc->flags); |
640 | mutex_unlock(&sysfs_lock); | |
641 | return 0; | |
642 | ||
c43960fb JH |
643 | err_free_data: |
644 | kfree(data); | |
645 | err_unlock: | |
0eb4c6c2 AC |
646 | mutex_unlock(&sysfs_lock); |
647 | gpiod_dbg(desc, "%s: status %d\n", __func__, status); | |
648 | return status; | |
649 | } | |
650 | EXPORT_SYMBOL_GPL(gpiod_export); | |
651 | ||
c43960fb | 652 | static int match_export(struct device *dev, const void *desc) |
0eb4c6c2 | 653 | { |
c43960fb JH |
654 | struct gpiod_data *data = dev_get_drvdata(dev); |
655 | ||
656 | return data->desc == desc; | |
0eb4c6c2 AC |
657 | } |
658 | ||
659 | /** | |
660 | * gpiod_export_link - create a sysfs link to an exported GPIO node | |
661 | * @dev: device under which to create symlink | |
662 | * @name: name of the symlink | |
2d9d0519 | 663 | * @desc: GPIO to create symlink to, already exported |
0eb4c6c2 AC |
664 | * |
665 | * Set up a symlink from /sys/.../dev/name to /sys/class/gpio/gpioN | |
666 | * node. Caller is responsible for unlinking. | |
667 | * | |
668 | * Returns zero on success, else an error. | |
669 | */ | |
670 | int gpiod_export_link(struct device *dev, const char *name, | |
671 | struct gpio_desc *desc) | |
672 | { | |
56d30ec1 JH |
673 | struct device *cdev; |
674 | int ret; | |
0eb4c6c2 AC |
675 | |
676 | if (!desc) { | |
677 | pr_warn("%s: invalid GPIO\n", __func__); | |
678 | return -EINVAL; | |
679 | } | |
680 | ||
56d30ec1 JH |
681 | cdev = class_find_device(&gpio_class, NULL, desc, match_export); |
682 | if (!cdev) | |
683 | return -ENODEV; | |
0eb4c6c2 | 684 | |
56d30ec1 JH |
685 | ret = sysfs_create_link(&dev->kobj, &cdev->kobj, name); |
686 | put_device(cdev); | |
0eb4c6c2 | 687 | |
56d30ec1 | 688 | return ret; |
0eb4c6c2 AC |
689 | } |
690 | EXPORT_SYMBOL_GPL(gpiod_export_link); | |
691 | ||
0eb4c6c2 | 692 | /** |
31963eb0 | 693 | * gpiod_unexport - reverse effect of gpiod_export() |
2d9d0519 | 694 | * @desc: GPIO to make unavailable |
0eb4c6c2 | 695 | * |
31963eb0 | 696 | * This is implicit on gpiod_free(). |
0eb4c6c2 AC |
697 | */ |
698 | void gpiod_unexport(struct gpio_desc *desc) | |
699 | { | |
72eba6f6 JH |
700 | struct gpiod_data *data; |
701 | struct device *dev; | |
0eb4c6c2 AC |
702 | |
703 | if (!desc) { | |
704 | pr_warn("%s: invalid GPIO\n", __func__); | |
705 | return; | |
706 | } | |
707 | ||
708 | mutex_lock(&sysfs_lock); | |
709 | ||
72eba6f6 JH |
710 | if (!test_bit(FLAG_EXPORT, &desc->flags)) |
711 | goto err_unlock; | |
0eb4c6c2 | 712 | |
72eba6f6 JH |
713 | dev = class_find_device(&gpio_class, NULL, desc, match_export); |
714 | if (!dev) | |
715 | goto err_unlock; | |
716 | ||
717 | data = dev_get_drvdata(dev); | |
718 | ||
72eba6f6 JH |
719 | clear_bit(FLAG_EXPORT, &desc->flags); |
720 | ||
721 | device_unregister(dev); | |
722 | ||
723 | /* | |
724 | * Release irq after deregistration to prevent race with edge_store. | |
725 | */ | |
cef1717b | 726 | if (data->irq_flags) |
72eba6f6 | 727 | gpio_sysfs_free_irq(dev); |
0eb4c6c2 AC |
728 | |
729 | mutex_unlock(&sysfs_lock); | |
730 | ||
72eba6f6 JH |
731 | put_device(dev); |
732 | kfree(data); | |
0eb4c6c2 | 733 | |
72eba6f6 JH |
734 | return; |
735 | ||
736 | err_unlock: | |
737 | mutex_unlock(&sysfs_lock); | |
0eb4c6c2 AC |
738 | } |
739 | EXPORT_SYMBOL_GPL(gpiod_unexport); | |
740 | ||
afbc4f31 | 741 | int gpiochip_sysfs_register(struct gpio_device *gdev) |
0eb4c6c2 | 742 | { |
0eb4c6c2 | 743 | struct device *dev; |
d27c1728 | 744 | struct device *parent; |
afbc4f31 | 745 | struct gpio_chip *chip = gdev->chip; |
0eb4c6c2 | 746 | |
426577bd JH |
747 | /* |
748 | * Many systems add gpio chips for SOC support very early, | |
0eb4c6c2 | 749 | * before driver model support is available. In those cases we |
426577bd | 750 | * register later, in gpiolib_sysfs_init() ... here we just |
0eb4c6c2 AC |
751 | * verify that _some_ field of gpio_class got initialized. |
752 | */ | |
753 | if (!gpio_class.p) | |
754 | return 0; | |
755 | ||
d27c1728 BJZ |
756 | /* |
757 | * For sysfs backward compatibility we need to preserve this | |
758 | * preferred parenting to the gpio_chip parent field, if set. | |
759 | */ | |
760 | if (chip->parent) | |
761 | parent = chip->parent; | |
762 | else | |
763 | parent = &gdev->dev; | |
764 | ||
0eb4c6c2 | 765 | /* use chip->base for the ID; it's already known to be unique */ |
ddd8891e GU |
766 | dev = device_create_with_groups(&gpio_class, parent, MKDEV(0, 0), chip, |
767 | gpiochip_groups, GPIOCHIP_NAME "%d", | |
768 | chip->base); | |
121b6a79 | 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); |