Commit | Line | Data |
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dae5f0af | 1 | // SPDX-License-Identifier: GPL-2.0 |
380c7ba3 AS |
2 | |
3 | #include <linux/bitops.h> | |
4 | #include <linux/device.h> | |
0eb4c6c2 | 5 | #include <linux/idr.h> |
380c7ba3 AS |
6 | #include <linux/init.h> |
7 | #include <linux/interrupt.h> | |
8 | #include <linux/kdev_t.h> | |
9 | #include <linux/kstrtox.h> | |
10 | #include <linux/list.h> | |
0eb4c6c2 | 11 | #include <linux/mutex.h> |
380c7ba3 AS |
12 | #include <linux/printk.h> |
13 | #include <linux/slab.h> | |
14 | #include <linux/spinlock.h> | |
15 | #include <linux/string.h> | |
0eb4c6c2 | 16 | #include <linux/sysfs.h> |
380c7ba3 AS |
17 | #include <linux/types.h> |
18 | ||
0eb4c6c2 AC |
19 | #include <linux/gpio/consumer.h> |
20 | #include <linux/gpio/driver.h> | |
0eb4c6c2 AC |
21 | |
22 | #include "gpiolib.h" | |
ef087d8e | 23 | #include "gpiolib-sysfs.h" |
0eb4c6c2 | 24 | |
380c7ba3 AS |
25 | struct kernfs_node; |
26 | ||
667630ed | 27 | #define GPIO_IRQF_TRIGGER_NONE 0 |
cef1717b JH |
28 | #define GPIO_IRQF_TRIGGER_FALLING BIT(0) |
29 | #define GPIO_IRQF_TRIGGER_RISING BIT(1) | |
30 | #define GPIO_IRQF_TRIGGER_BOTH (GPIO_IRQF_TRIGGER_FALLING | \ | |
31 | GPIO_IRQF_TRIGGER_RISING) | |
32 | ||
c43960fb JH |
33 | struct gpiod_data { |
34 | struct gpio_desc *desc; | |
6ffcb797 JH |
35 | |
36 | struct mutex mutex; | |
a08f5c21 | 37 | struct kernfs_node *value_kn; |
2ec74a95 | 38 | int irq; |
cef1717b | 39 | unsigned char irq_flags; |
427fdeef JH |
40 | |
41 | bool direction_can_change; | |
c43960fb JH |
42 | }; |
43 | ||
6ffcb797 JH |
44 | /* |
45 | * Lock to serialise gpiod export and unexport, and prevent re-export of | |
46 | * gpiod whose chip is being unregistered. | |
0eb4c6c2 AC |
47 | */ |
48 | static DEFINE_MUTEX(sysfs_lock); | |
49 | ||
50 | /* | |
51 | * /sys/class/gpio/gpioN... only for GPIOs that are exported | |
52 | * /direction | |
53 | * * MAY BE OMITTED if kernel won't allow direction changes | |
54 | * * is read/write as "in" or "out" | |
55 | * * may also be written as "high" or "low", initializing | |
56 | * output value as specified ("out" implies "low") | |
57 | * /value | |
58 | * * always readable, subject to hardware behavior | |
59 | * * may be writable, as zero/nonzero | |
60 | * /edge | |
61 | * * configures behavior of poll(2) on /value | |
62 | * * available only if pin can generate IRQs on input | |
63 | * * is read/write as "none", "falling", "rising", or "both" | |
64 | * /active_low | |
65 | * * configures polarity of /value | |
66 | * * is read/write as zero/nonzero | |
67 | * * also affects existing and subsequent "falling" and "rising" | |
68 | * /edge configuration | |
69 | */ | |
70 | ||
6beac9d1 | 71 | static ssize_t direction_show(struct device *dev, |
0eb4c6c2 AC |
72 | struct device_attribute *attr, char *buf) |
73 | { | |
c43960fb JH |
74 | struct gpiod_data *data = dev_get_drvdata(dev); |
75 | struct gpio_desc *desc = data->desc; | |
e28747da | 76 | int value; |
0eb4c6c2 | 77 | |
6ffcb797 | 78 | mutex_lock(&data->mutex); |
0eb4c6c2 | 79 | |
f0b7866a | 80 | gpiod_get_direction(desc); |
e28747da | 81 | value = !!test_bit(FLAG_IS_OUT, &desc->flags); |
0eb4c6c2 | 82 | |
6ffcb797 JH |
83 | mutex_unlock(&data->mutex); |
84 | ||
e28747da | 85 | return sysfs_emit(buf, "%s\n", value ? "out" : "in"); |
0eb4c6c2 AC |
86 | } |
87 | ||
6beac9d1 | 88 | static ssize_t direction_store(struct device *dev, |
0eb4c6c2 AC |
89 | struct device_attribute *attr, const char *buf, size_t size) |
90 | { | |
c43960fb JH |
91 | struct gpiod_data *data = dev_get_drvdata(dev); |
92 | struct gpio_desc *desc = data->desc; | |
0eb4c6c2 AC |
93 | ssize_t status; |
94 | ||
6ffcb797 | 95 | mutex_lock(&data->mutex); |
0eb4c6c2 | 96 | |
f0b7866a | 97 | if (sysfs_streq(buf, "high")) |
0eb4c6c2 AC |
98 | status = gpiod_direction_output_raw(desc, 1); |
99 | else if (sysfs_streq(buf, "out") || sysfs_streq(buf, "low")) | |
100 | status = gpiod_direction_output_raw(desc, 0); | |
101 | else if (sysfs_streq(buf, "in")) | |
102 | status = gpiod_direction_input(desc); | |
103 | else | |
104 | status = -EINVAL; | |
105 | ||
6ffcb797 JH |
106 | mutex_unlock(&data->mutex); |
107 | ||
0eb4c6c2 AC |
108 | return status ? : size; |
109 | } | |
6beac9d1 | 110 | static DEVICE_ATTR_RW(direction); |
0eb4c6c2 | 111 | |
6beac9d1 | 112 | static ssize_t value_show(struct device *dev, |
0eb4c6c2 AC |
113 | struct device_attribute *attr, char *buf) |
114 | { | |
c43960fb JH |
115 | struct gpiod_data *data = dev_get_drvdata(dev); |
116 | struct gpio_desc *desc = data->desc; | |
0eb4c6c2 AC |
117 | ssize_t status; |
118 | ||
6ffcb797 | 119 | mutex_lock(&data->mutex); |
0eb4c6c2 | 120 | |
9295c012 | 121 | status = gpiod_get_value_cansleep(desc); |
0eb4c6c2 | 122 | |
6ffcb797 JH |
123 | mutex_unlock(&data->mutex); |
124 | ||
e28747da AS |
125 | if (status < 0) |
126 | return status; | |
127 | ||
128 | return sysfs_emit(buf, "%zd\n", status); | |
0eb4c6c2 AC |
129 | } |
130 | ||
6beac9d1 | 131 | static ssize_t value_store(struct device *dev, |
0eb4c6c2 AC |
132 | struct device_attribute *attr, const char *buf, size_t size) |
133 | { | |
c43960fb JH |
134 | struct gpiod_data *data = dev_get_drvdata(dev); |
135 | struct gpio_desc *desc = data->desc; | |
6b3c1791 AS |
136 | ssize_t status; |
137 | long value; | |
138 | ||
139 | status = kstrtol(buf, 0, &value); | |
0eb4c6c2 | 140 | |
6ffcb797 | 141 | mutex_lock(&data->mutex); |
0eb4c6c2 | 142 | |
f0b7866a | 143 | if (!test_bit(FLAG_IS_OUT, &desc->flags)) { |
0eb4c6c2 | 144 | status = -EPERM; |
6b3c1791 AS |
145 | } else if (status == 0) { |
146 | gpiod_set_value_cansleep(desc, value); | |
147 | status = size; | |
0eb4c6c2 AC |
148 | } |
149 | ||
6ffcb797 JH |
150 | mutex_unlock(&data->mutex); |
151 | ||
0eb4c6c2 AC |
152 | return status; |
153 | } | |
7fda9100 | 154 | static DEVICE_ATTR_PREALLOC(value, S_IWUSR | S_IRUGO, value_show, value_store); |
0eb4c6c2 AC |
155 | |
156 | static irqreturn_t gpio_sysfs_irq(int irq, void *priv) | |
157 | { | |
a08f5c21 JH |
158 | struct gpiod_data *data = priv; |
159 | ||
160 | sysfs_notify_dirent(data->value_kn); | |
0eb4c6c2 | 161 | |
0eb4c6c2 AC |
162 | return IRQ_HANDLED; |
163 | } | |
164 | ||
6ffcb797 | 165 | /* Caller holds gpiod-data mutex. */ |
cef1717b | 166 | static int gpio_sysfs_request_irq(struct device *dev, unsigned char flags) |
0eb4c6c2 | 167 | { |
513246a3 BG |
168 | struct gpiod_data *data = dev_get_drvdata(dev); |
169 | struct gpio_desc *desc = data->desc; | |
170 | unsigned long irq_flags; | |
171 | int ret; | |
0eb4c6c2 | 172 | |
2ec74a95 JH |
173 | data->irq = gpiod_to_irq(desc); |
174 | if (data->irq < 0) | |
0eb4c6c2 AC |
175 | return -EIO; |
176 | ||
2ec74a95 JH |
177 | data->value_kn = sysfs_get_dirent(dev->kobj.sd, "value"); |
178 | if (!data->value_kn) | |
179 | return -ENODEV; | |
0eb4c6c2 AC |
180 | |
181 | irq_flags = IRQF_SHARED; | |
cef1717b | 182 | if (flags & GPIO_IRQF_TRIGGER_FALLING) |
0eb4c6c2 AC |
183 | irq_flags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ? |
184 | IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING; | |
cef1717b | 185 | if (flags & GPIO_IRQF_TRIGGER_RISING) |
0eb4c6c2 AC |
186 | irq_flags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ? |
187 | IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING; | |
188 | ||
52176d0d JH |
189 | /* |
190 | * FIXME: This should be done in the irq_request_resources callback | |
191 | * when the irq is requested, but a few drivers currently fail | |
192 | * to do so. | |
193 | * | |
194 | * Remove this redundant call (along with the corresponding | |
195 | * unlock) when those drivers have been fixed. | |
196 | */ | |
fdeb8e15 | 197 | ret = gpiochip_lock_as_irq(desc->gdev->chip, gpio_chip_hwgpio(desc)); |
0eb4c6c2 | 198 | if (ret < 0) |
2ec74a95 | 199 | goto err_put_kn; |
0eb4c6c2 | 200 | |
2ec74a95 | 201 | ret = request_any_context_irq(data->irq, gpio_sysfs_irq, irq_flags, |
a08f5c21 | 202 | "gpiolib", data); |
52176d0d JH |
203 | if (ret < 0) |
204 | goto err_unlock; | |
0eb4c6c2 | 205 | |
cef1717b | 206 | data->irq_flags = flags; |
2ec74a95 | 207 | |
0eb4c6c2 AC |
208 | return 0; |
209 | ||
52176d0d | 210 | err_unlock: |
fdeb8e15 | 211 | gpiochip_unlock_as_irq(desc->gdev->chip, gpio_chip_hwgpio(desc)); |
2ec74a95 JH |
212 | err_put_kn: |
213 | sysfs_put(data->value_kn); | |
214 | ||
0eb4c6c2 AC |
215 | return ret; |
216 | } | |
217 | ||
6ffcb797 JH |
218 | /* |
219 | * Caller holds gpiod-data mutex (unless called after class-device | |
220 | * deregistration). | |
221 | */ | |
2ec74a95 JH |
222 | static void gpio_sysfs_free_irq(struct device *dev) |
223 | { | |
224 | struct gpiod_data *data = dev_get_drvdata(dev); | |
225 | struct gpio_desc *desc = data->desc; | |
226 | ||
cef1717b | 227 | data->irq_flags = 0; |
2ec74a95 | 228 | free_irq(data->irq, data); |
fdeb8e15 | 229 | gpiochip_unlock_as_irq(desc->gdev->chip, gpio_chip_hwgpio(desc)); |
2ec74a95 JH |
230 | sysfs_put(data->value_kn); |
231 | } | |
232 | ||
667630ed AS |
233 | static const char * const trigger_names[] = { |
234 | [GPIO_IRQF_TRIGGER_NONE] = "none", | |
235 | [GPIO_IRQF_TRIGGER_FALLING] = "falling", | |
236 | [GPIO_IRQF_TRIGGER_RISING] = "rising", | |
237 | [GPIO_IRQF_TRIGGER_BOTH] = "both", | |
0eb4c6c2 AC |
238 | }; |
239 | ||
6beac9d1 | 240 | static ssize_t edge_show(struct device *dev, |
0eb4c6c2 AC |
241 | struct device_attribute *attr, char *buf) |
242 | { | |
c43960fb | 243 | struct gpiod_data *data = dev_get_drvdata(dev); |
667630ed | 244 | int flags; |
0eb4c6c2 | 245 | |
6ffcb797 | 246 | mutex_lock(&data->mutex); |
0eb4c6c2 | 247 | |
667630ed | 248 | flags = data->irq_flags; |
0eb4c6c2 | 249 | |
6ffcb797 JH |
250 | mutex_unlock(&data->mutex); |
251 | ||
667630ed | 252 | if (flags >= ARRAY_SIZE(trigger_names)) |
e28747da AS |
253 | return 0; |
254 | ||
667630ed | 255 | return sysfs_emit(buf, "%s\n", trigger_names[flags]); |
0eb4c6c2 AC |
256 | } |
257 | ||
6beac9d1 | 258 | static ssize_t edge_store(struct device *dev, |
0eb4c6c2 AC |
259 | struct device_attribute *attr, const char *buf, size_t size) |
260 | { | |
b91e1807 | 261 | struct gpiod_data *data = dev_get_drvdata(dev); |
513246a3 | 262 | ssize_t status = size; |
667630ed | 263 | int flags; |
e4339ce3 | 264 | |
667630ed AS |
265 | flags = sysfs_match_string(trigger_names, buf); |
266 | if (flags < 0) | |
267 | return flags; | |
b91e1807 | 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 | { |
513246a3 BG |
295 | struct gpiod_data *data = dev_get_drvdata(dev); |
296 | unsigned int flags = data->irq_flags; | |
297 | struct gpio_desc *desc = data->desc; | |
298 | int status = 0; | |
299 | ||
0eb4c6c2 AC |
300 | |
301 | if (!!test_bit(FLAG_ACTIVE_LOW, &desc->flags) == !!value) | |
302 | return 0; | |
303 | ||
fd80b8ba | 304 | assign_bit(FLAG_ACTIVE_LOW, &desc->flags, value); |
0eb4c6c2 AC |
305 | |
306 | /* reconfigure poll(2) support if enabled on one edge only */ | |
cef1717b JH |
307 | if (flags == GPIO_IRQF_TRIGGER_FALLING || |
308 | flags == GPIO_IRQF_TRIGGER_RISING) { | |
2ec74a95 | 309 | gpio_sysfs_free_irq(dev); |
cef1717b | 310 | status = gpio_sysfs_request_irq(dev, flags); |
0eb4c6c2 AC |
311 | } |
312 | ||
313 | return status; | |
314 | } | |
315 | ||
6beac9d1 | 316 | static ssize_t active_low_show(struct device *dev, |
0eb4c6c2 AC |
317 | struct device_attribute *attr, char *buf) |
318 | { | |
c43960fb JH |
319 | struct gpiod_data *data = dev_get_drvdata(dev); |
320 | struct gpio_desc *desc = data->desc; | |
e28747da | 321 | int value; |
0eb4c6c2 | 322 | |
6ffcb797 | 323 | mutex_lock(&data->mutex); |
0eb4c6c2 | 324 | |
e28747da | 325 | value = !!test_bit(FLAG_ACTIVE_LOW, &desc->flags); |
0eb4c6c2 | 326 | |
6ffcb797 | 327 | mutex_unlock(&data->mutex); |
0eb4c6c2 | 328 | |
e28747da | 329 | return sysfs_emit(buf, "%d\n", value); |
0eb4c6c2 AC |
330 | } |
331 | ||
6beac9d1 | 332 | static ssize_t active_low_store(struct device *dev, |
0eb4c6c2 AC |
333 | struct device_attribute *attr, const char *buf, size_t size) |
334 | { | |
513246a3 BG |
335 | struct gpiod_data *data = dev_get_drvdata(dev); |
336 | ssize_t status; | |
337 | long value; | |
0eb4c6c2 | 338 | |
6b3c1791 AS |
339 | status = kstrtol(buf, 0, &value); |
340 | if (status) | |
341 | return status; | |
342 | ||
6ffcb797 | 343 | mutex_lock(&data->mutex); |
0eb4c6c2 | 344 | |
6b3c1791 | 345 | status = gpio_sysfs_set_active_low(dev, value); |
0eb4c6c2 | 346 | |
6ffcb797 | 347 | mutex_unlock(&data->mutex); |
0eb4c6c2 AC |
348 | |
349 | return status ? : size; | |
350 | } | |
6beac9d1 | 351 | static DEVICE_ATTR_RW(active_low); |
0eb4c6c2 | 352 | |
ebbeba12 JH |
353 | static umode_t gpio_is_visible(struct kobject *kobj, struct attribute *attr, |
354 | int n) | |
355 | { | |
97cd738c | 356 | struct device *dev = kobj_to_dev(kobj); |
c43960fb JH |
357 | struct gpiod_data *data = dev_get_drvdata(dev); |
358 | struct gpio_desc *desc = data->desc; | |
ebbeba12 | 359 | umode_t mode = attr->mode; |
427fdeef | 360 | bool show_direction = data->direction_can_change; |
ebbeba12 JH |
361 | |
362 | if (attr == &dev_attr_direction.attr) { | |
363 | if (!show_direction) | |
364 | mode = 0; | |
365 | } else if (attr == &dev_attr_edge.attr) { | |
366 | if (gpiod_to_irq(desc) < 0) | |
367 | mode = 0; | |
368 | if (!show_direction && test_bit(FLAG_IS_OUT, &desc->flags)) | |
369 | mode = 0; | |
370 | } | |
371 | ||
372 | return mode; | |
373 | } | |
374 | ||
0915e6fe | 375 | static struct attribute *gpio_attrs[] = { |
ebbeba12 JH |
376 | &dev_attr_direction.attr, |
377 | &dev_attr_edge.attr, | |
0eb4c6c2 AC |
378 | &dev_attr_value.attr, |
379 | &dev_attr_active_low.attr, | |
380 | NULL, | |
381 | }; | |
ebbeba12 JH |
382 | |
383 | static const struct attribute_group gpio_group = { | |
384 | .attrs = gpio_attrs, | |
385 | .is_visible = gpio_is_visible, | |
386 | }; | |
387 | ||
388 | static const struct attribute_group *gpio_groups[] = { | |
389 | &gpio_group, | |
390 | NULL | |
391 | }; | |
0eb4c6c2 AC |
392 | |
393 | /* | |
394 | * /sys/class/gpio/gpiochipN/ | |
395 | * /base ... matching gpio_chip.base (N) | |
396 | * /label ... matching gpio_chip.label | |
397 | * /ngpio ... matching gpio_chip.ngpio | |
398 | */ | |
399 | ||
6beac9d1 | 400 | static ssize_t base_show(struct device *dev, |
0eb4c6c2 AC |
401 | struct device_attribute *attr, char *buf) |
402 | { | |
513246a3 | 403 | const struct gpio_chip *chip = dev_get_drvdata(dev); |
0eb4c6c2 | 404 | |
9e23bf6b | 405 | return sysfs_emit(buf, "%d\n", chip->base); |
0eb4c6c2 | 406 | } |
6beac9d1 | 407 | static DEVICE_ATTR_RO(base); |
0eb4c6c2 | 408 | |
6beac9d1 | 409 | static ssize_t label_show(struct device *dev, |
0eb4c6c2 AC |
410 | struct device_attribute *attr, char *buf) |
411 | { | |
513246a3 | 412 | const struct gpio_chip *chip = dev_get_drvdata(dev); |
0eb4c6c2 | 413 | |
9e23bf6b | 414 | return sysfs_emit(buf, "%s\n", chip->label ?: ""); |
0eb4c6c2 | 415 | } |
6beac9d1 | 416 | static DEVICE_ATTR_RO(label); |
0eb4c6c2 | 417 | |
6beac9d1 | 418 | static ssize_t ngpio_show(struct device *dev, |
0eb4c6c2 AC |
419 | struct device_attribute *attr, char *buf) |
420 | { | |
513246a3 | 421 | const struct gpio_chip *chip = dev_get_drvdata(dev); |
0eb4c6c2 | 422 | |
9e23bf6b | 423 | return sysfs_emit(buf, "%u\n", chip->ngpio); |
0eb4c6c2 | 424 | } |
6beac9d1 | 425 | static DEVICE_ATTR_RO(ngpio); |
0eb4c6c2 | 426 | |
121b6a79 | 427 | static struct attribute *gpiochip_attrs[] = { |
0eb4c6c2 AC |
428 | &dev_attr_base.attr, |
429 | &dev_attr_label.attr, | |
430 | &dev_attr_ngpio.attr, | |
431 | NULL, | |
432 | }; | |
121b6a79 | 433 | ATTRIBUTE_GROUPS(gpiochip); |
0eb4c6c2 AC |
434 | |
435 | /* | |
436 | * /sys/class/gpio/export ... write-only | |
437 | * integer N ... number of GPIO to export (full access) | |
438 | * /sys/class/gpio/unexport ... write-only | |
439 | * integer N ... number of GPIO to unexport | |
440 | */ | |
75a2d422 GKH |
441 | static ssize_t export_store(const struct class *class, |
442 | const struct class_attribute *attr, | |
0eb4c6c2 AC |
443 | const char *buf, size_t len) |
444 | { | |
513246a3 BG |
445 | struct gpio_desc *desc; |
446 | struct gpio_chip *gc; | |
447 | int status, offset; | |
448 | long gpio; | |
0eb4c6c2 AC |
449 | |
450 | status = kstrtol(buf, 0, &gpio); | |
451 | if (status < 0) | |
452 | goto done; | |
453 | ||
f13a0b0b | 454 | desc = gpio_to_desc(gpio); |
0eb4c6c2 AC |
455 | /* reject invalid GPIOs */ |
456 | if (!desc) { | |
457 | pr_warn("%s: invalid GPIO %ld\n", __func__, gpio); | |
458 | return -EINVAL; | |
459 | } | |
23cf00dd MV |
460 | gc = desc->gdev->chip; |
461 | offset = gpio_chip_hwgpio(desc); | |
462 | if (!gpiochip_line_is_valid(gc, offset)) { | |
463 | pr_warn("%s: GPIO %ld masked\n", __func__, gpio); | |
464 | return -EINVAL; | |
465 | } | |
0eb4c6c2 AC |
466 | |
467 | /* No extra locking here; FLAG_SYSFS just signifies that the | |
468 | * request and export were done by on behalf of userspace, so | |
469 | * they may be undone on its behalf too. | |
470 | */ | |
471 | ||
95a4eed7 AS |
472 | status = gpiod_request_user(desc, "sysfs"); |
473 | if (status) | |
0eb4c6c2 | 474 | goto done; |
e10f72bf AJ |
475 | |
476 | status = gpiod_set_transitory(desc, false); | |
95dd1e34 BS |
477 | if (status) { |
478 | gpiod_free(desc); | |
479 | goto done; | |
e10f72bf | 480 | } |
0eb4c6c2 | 481 | |
95dd1e34 BS |
482 | status = gpiod_export(desc, true); |
483 | if (status < 0) | |
484 | gpiod_free(desc); | |
485 | else | |
486 | set_bit(FLAG_SYSFS, &desc->flags); | |
487 | ||
0eb4c6c2 AC |
488 | done: |
489 | if (status) | |
490 | pr_debug("%s: status %d\n", __func__, status); | |
491 | return status ? : len; | |
492 | } | |
d83bb159 | 493 | static CLASS_ATTR_WO(export); |
0eb4c6c2 | 494 | |
75a2d422 GKH |
495 | static ssize_t unexport_store(const struct class *class, |
496 | const struct class_attribute *attr, | |
0eb4c6c2 AC |
497 | const char *buf, size_t len) |
498 | { | |
513246a3 BG |
499 | struct gpio_desc *desc; |
500 | int status; | |
501 | long gpio; | |
0eb4c6c2 AC |
502 | |
503 | status = kstrtol(buf, 0, &gpio); | |
504 | if (status < 0) | |
505 | goto done; | |
506 | ||
f13a0b0b | 507 | desc = gpio_to_desc(gpio); |
d74e3166 | 508 | /* reject bogus commands (gpiod_unexport() ignores them) */ |
0eb4c6c2 AC |
509 | if (!desc) { |
510 | pr_warn("%s: invalid GPIO %ld\n", __func__, gpio); | |
511 | return -EINVAL; | |
512 | } | |
513 | ||
514 | status = -EINVAL; | |
515 | ||
516 | /* No extra locking here; FLAG_SYSFS just signifies that the | |
517 | * request and export were done by on behalf of userspace, so | |
518 | * they may be undone on its behalf too. | |
519 | */ | |
520 | if (test_and_clear_bit(FLAG_SYSFS, &desc->flags)) { | |
20d9b3b5 | 521 | gpiod_unexport(desc); |
0eb4c6c2 | 522 | gpiod_free(desc); |
20d9b3b5 | 523 | status = 0; |
0eb4c6c2 AC |
524 | } |
525 | done: | |
526 | if (status) | |
527 | pr_debug("%s: status %d\n", __func__, status); | |
528 | return status ? : len; | |
529 | } | |
d83bb159 | 530 | static CLASS_ATTR_WO(unexport); |
0eb4c6c2 | 531 | |
d83bb159 GKH |
532 | static struct attribute *gpio_class_attrs[] = { |
533 | &class_attr_export.attr, | |
534 | &class_attr_unexport.attr, | |
535 | NULL, | |
0eb4c6c2 | 536 | }; |
d83bb159 | 537 | ATTRIBUTE_GROUPS(gpio_class); |
0eb4c6c2 AC |
538 | |
539 | static struct class gpio_class = { | |
540 | .name = "gpio", | |
d83bb159 | 541 | .class_groups = gpio_class_groups, |
0eb4c6c2 AC |
542 | }; |
543 | ||
544 | ||
545 | /** | |
546 | * gpiod_export - export a GPIO through sysfs | |
2d9d0519 TR |
547 | * @desc: GPIO to make available, already requested |
548 | * @direction_may_change: true if userspace may change GPIO direction | |
0eb4c6c2 AC |
549 | * Context: arch_initcall or later |
550 | * | |
551 | * When drivers want to make a GPIO accessible to userspace after they | |
552 | * have requested it -- perhaps while debugging, or as part of their | |
553 | * public interface -- they may use this routine. If the GPIO can | |
554 | * change direction (some can't) and the caller allows it, userspace | |
555 | * will see "direction" sysfs attribute which may be used to change | |
556 | * the gpio's direction. A "value" attribute will always be provided. | |
557 | * | |
558 | * Returns zero on success, else an error. | |
559 | */ | |
560 | int gpiod_export(struct gpio_desc *desc, bool direction_may_change) | |
561 | { | |
513246a3 BG |
562 | const char *ioname = NULL; |
563 | struct gpio_device *gdev; | |
564 | struct gpiod_data *data; | |
565 | struct gpio_chip *chip; | |
566 | unsigned long flags; | |
567 | struct device *dev; | |
568 | int status, offset; | |
0eb4c6c2 AC |
569 | |
570 | /* can't export until sysfs is available ... */ | |
6f14c022 | 571 | if (!class_is_registered(&gpio_class)) { |
0eb4c6c2 AC |
572 | pr_debug("%s: called too early!\n", __func__); |
573 | return -ENOENT; | |
574 | } | |
575 | ||
576 | if (!desc) { | |
577 | pr_debug("%s: invalid gpio descriptor\n", __func__); | |
578 | return -EINVAL; | |
579 | } | |
580 | ||
fdeb8e15 LW |
581 | gdev = desc->gdev; |
582 | chip = gdev->chip; | |
483d8211 | 583 | |
0eb4c6c2 AC |
584 | mutex_lock(&sysfs_lock); |
585 | ||
483d8211 | 586 | /* check if chip is being removed */ |
afbc4f31 | 587 | if (!chip || !gdev->mockdev) { |
483d8211 | 588 | status = -ENODEV; |
c43960fb | 589 | goto err_unlock; |
483d8211 JH |
590 | } |
591 | ||
0eb4c6c2 AC |
592 | spin_lock_irqsave(&gpio_lock, flags); |
593 | if (!test_bit(FLAG_REQUESTED, &desc->flags) || | |
594 | test_bit(FLAG_EXPORT, &desc->flags)) { | |
595 | spin_unlock_irqrestore(&gpio_lock, flags); | |
596 | gpiod_dbg(desc, "%s: unavailable (requested=%d, exported=%d)\n", | |
597 | __func__, | |
598 | test_bit(FLAG_REQUESTED, &desc->flags), | |
599 | test_bit(FLAG_EXPORT, &desc->flags)); | |
600 | status = -EPERM; | |
c43960fb | 601 | goto err_unlock; |
0eb4c6c2 | 602 | } |
0eb4c6c2 AC |
603 | spin_unlock_irqrestore(&gpio_lock, flags); |
604 | ||
c43960fb JH |
605 | data = kzalloc(sizeof(*data), GFP_KERNEL); |
606 | if (!data) { | |
607 | status = -ENOMEM; | |
608 | goto err_unlock; | |
609 | } | |
610 | ||
611 | data->desc = desc; | |
6ffcb797 | 612 | mutex_init(&data->mutex); |
427fdeef JH |
613 | if (chip->direction_input && chip->direction_output) |
614 | data->direction_can_change = direction_may_change; | |
615 | else | |
616 | data->direction_can_change = false; | |
c43960fb | 617 | |
0eb4c6c2 | 618 | offset = gpio_chip_hwgpio(desc); |
cecf58ab JH |
619 | if (chip->names && chip->names[offset]) |
620 | ioname = chip->names[offset]; | |
0eb4c6c2 | 621 | |
ff2b1359 | 622 | dev = device_create_with_groups(&gpio_class, &gdev->dev, |
c43960fb | 623 | MKDEV(0, 0), data, gpio_groups, |
0915e6fe JH |
624 | ioname ? ioname : "gpio%u", |
625 | desc_to_gpio(desc)); | |
0eb4c6c2 AC |
626 | if (IS_ERR(dev)) { |
627 | status = PTR_ERR(dev); | |
c43960fb | 628 | goto err_free_data; |
0eb4c6c2 AC |
629 | } |
630 | ||
0eb4c6c2 AC |
631 | set_bit(FLAG_EXPORT, &desc->flags); |
632 | mutex_unlock(&sysfs_lock); | |
633 | return 0; | |
634 | ||
c43960fb JH |
635 | err_free_data: |
636 | kfree(data); | |
637 | err_unlock: | |
0eb4c6c2 AC |
638 | mutex_unlock(&sysfs_lock); |
639 | gpiod_dbg(desc, "%s: status %d\n", __func__, status); | |
640 | return status; | |
641 | } | |
642 | EXPORT_SYMBOL_GPL(gpiod_export); | |
643 | ||
c43960fb | 644 | static int match_export(struct device *dev, const void *desc) |
0eb4c6c2 | 645 | { |
c43960fb JH |
646 | struct gpiod_data *data = dev_get_drvdata(dev); |
647 | ||
648 | return data->desc == desc; | |
0eb4c6c2 AC |
649 | } |
650 | ||
651 | /** | |
652 | * gpiod_export_link - create a sysfs link to an exported GPIO node | |
653 | * @dev: device under which to create symlink | |
654 | * @name: name of the symlink | |
2d9d0519 | 655 | * @desc: GPIO to create symlink to, already exported |
0eb4c6c2 AC |
656 | * |
657 | * Set up a symlink from /sys/.../dev/name to /sys/class/gpio/gpioN | |
658 | * node. Caller is responsible for unlinking. | |
659 | * | |
660 | * Returns zero on success, else an error. | |
661 | */ | |
662 | int gpiod_export_link(struct device *dev, const char *name, | |
663 | struct gpio_desc *desc) | |
664 | { | |
56d30ec1 JH |
665 | struct device *cdev; |
666 | int ret; | |
0eb4c6c2 AC |
667 | |
668 | if (!desc) { | |
669 | pr_warn("%s: invalid GPIO\n", __func__); | |
670 | return -EINVAL; | |
671 | } | |
672 | ||
56d30ec1 JH |
673 | cdev = class_find_device(&gpio_class, NULL, desc, match_export); |
674 | if (!cdev) | |
675 | return -ENODEV; | |
0eb4c6c2 | 676 | |
56d30ec1 JH |
677 | ret = sysfs_create_link(&dev->kobj, &cdev->kobj, name); |
678 | put_device(cdev); | |
0eb4c6c2 | 679 | |
56d30ec1 | 680 | return ret; |
0eb4c6c2 AC |
681 | } |
682 | EXPORT_SYMBOL_GPL(gpiod_export_link); | |
683 | ||
0eb4c6c2 | 684 | /** |
31963eb0 | 685 | * gpiod_unexport - reverse effect of gpiod_export() |
2d9d0519 | 686 | * @desc: GPIO to make unavailable |
0eb4c6c2 | 687 | * |
31963eb0 | 688 | * This is implicit on gpiod_free(). |
0eb4c6c2 AC |
689 | */ |
690 | void gpiod_unexport(struct gpio_desc *desc) | |
691 | { | |
72eba6f6 JH |
692 | struct gpiod_data *data; |
693 | struct device *dev; | |
0eb4c6c2 AC |
694 | |
695 | if (!desc) { | |
696 | pr_warn("%s: invalid GPIO\n", __func__); | |
697 | return; | |
698 | } | |
699 | ||
700 | mutex_lock(&sysfs_lock); | |
701 | ||
72eba6f6 JH |
702 | if (!test_bit(FLAG_EXPORT, &desc->flags)) |
703 | goto err_unlock; | |
0eb4c6c2 | 704 | |
72eba6f6 JH |
705 | dev = class_find_device(&gpio_class, NULL, desc, match_export); |
706 | if (!dev) | |
707 | goto err_unlock; | |
708 | ||
709 | data = dev_get_drvdata(dev); | |
710 | ||
72eba6f6 JH |
711 | clear_bit(FLAG_EXPORT, &desc->flags); |
712 | ||
713 | device_unregister(dev); | |
714 | ||
715 | /* | |
716 | * Release irq after deregistration to prevent race with edge_store. | |
717 | */ | |
cef1717b | 718 | if (data->irq_flags) |
72eba6f6 | 719 | gpio_sysfs_free_irq(dev); |
0eb4c6c2 AC |
720 | |
721 | mutex_unlock(&sysfs_lock); | |
722 | ||
72eba6f6 JH |
723 | put_device(dev); |
724 | kfree(data); | |
0eb4c6c2 | 725 | |
72eba6f6 JH |
726 | return; |
727 | ||
728 | err_unlock: | |
729 | mutex_unlock(&sysfs_lock); | |
0eb4c6c2 AC |
730 | } |
731 | EXPORT_SYMBOL_GPL(gpiod_unexport); | |
732 | ||
afbc4f31 | 733 | int gpiochip_sysfs_register(struct gpio_device *gdev) |
0eb4c6c2 | 734 | { |
afbc4f31 | 735 | struct gpio_chip *chip = gdev->chip; |
513246a3 BG |
736 | struct device *parent; |
737 | struct device *dev; | |
0eb4c6c2 | 738 | |
426577bd JH |
739 | /* |
740 | * Many systems add gpio chips for SOC support very early, | |
0eb4c6c2 | 741 | * before driver model support is available. In those cases we |
426577bd | 742 | * register later, in gpiolib_sysfs_init() ... here we just |
0eb4c6c2 AC |
743 | * verify that _some_ field of gpio_class got initialized. |
744 | */ | |
6f14c022 | 745 | if (!class_is_registered(&gpio_class)) |
0eb4c6c2 AC |
746 | return 0; |
747 | ||
d27c1728 BJZ |
748 | /* |
749 | * For sysfs backward compatibility we need to preserve this | |
750 | * preferred parenting to the gpio_chip parent field, if set. | |
751 | */ | |
752 | if (chip->parent) | |
753 | parent = chip->parent; | |
754 | else | |
755 | parent = &gdev->dev; | |
756 | ||
0eb4c6c2 | 757 | /* use chip->base for the ID; it's already known to be unique */ |
ddd8891e GU |
758 | dev = device_create_with_groups(&gpio_class, parent, MKDEV(0, 0), chip, |
759 | gpiochip_groups, GPIOCHIP_NAME "%d", | |
760 | chip->base); | |
121b6a79 | 761 | if (IS_ERR(dev)) |
6a4b6b0a | 762 | return PTR_ERR(dev); |
3ff74be5 JH |
763 | |
764 | mutex_lock(&sysfs_lock); | |
afbc4f31 | 765 | gdev->mockdev = dev; |
0eb4c6c2 AC |
766 | mutex_unlock(&sysfs_lock); |
767 | ||
6a4b6b0a | 768 | return 0; |
0eb4c6c2 AC |
769 | } |
770 | ||
afbc4f31 | 771 | void gpiochip_sysfs_unregister(struct gpio_device *gdev) |
0eb4c6c2 | 772 | { |
483d8211 | 773 | struct gpio_desc *desc; |
afbc4f31 | 774 | struct gpio_chip *chip = gdev->chip; |
0eb4c6c2 | 775 | |
afbc4f31 | 776 | if (!gdev->mockdev) |
6a4b6b0a | 777 | return; |
0eb4c6c2 | 778 | |
afbc4f31 | 779 | device_unregister(gdev->mockdev); |
6a4b6b0a JH |
780 | |
781 | /* prevent further gpiod exports */ | |
782 | mutex_lock(&sysfs_lock); | |
afbc4f31 | 783 | gdev->mockdev = NULL; |
6a4b6b0a | 784 | mutex_unlock(&sysfs_lock); |
483d8211 JH |
785 | |
786 | /* unregister gpiod class devices owned by sysfs */ | |
20d9b3b5 AS |
787 | for_each_gpio_desc_with_flag(chip, desc, FLAG_SYSFS) { |
788 | gpiod_unexport(desc); | |
80c78fbe | 789 | gpiod_free(desc); |
20d9b3b5 | 790 | } |
0eb4c6c2 AC |
791 | } |
792 | ||
793 | static int __init gpiolib_sysfs_init(void) | |
794 | { | |
efb8235b BG |
795 | int status; |
796 | unsigned long flags; | |
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 | |
d74e3166 | 807 | * registered, and so arch_initcall() can always gpiod_export(). |
0eb4c6c2 | 808 | */ |
efb8235b BG |
809 | spin_lock_irqsave(&gpio_lock, flags); |
810 | list_for_each_entry(gdev, &gpio_devices, list) { | |
811 | if (gdev->mockdev) | |
812 | continue; | |
813 | ||
814 | /* | |
815 | * TODO we yield gpio_lock here because | |
816 | * gpiochip_sysfs_register() acquires a mutex. This is unsafe | |
817 | * and needs to be fixed. | |
818 | * | |
819 | * Also it would be nice to use gpio_device_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 | */ | |
823 | spin_unlock_irqrestore(&gpio_lock, flags); | |
824 | status = gpiochip_sysfs_register(gdev); | |
825 | spin_lock_irqsave(&gpio_lock, flags); | |
826 | } | |
827 | spin_unlock_irqrestore(&gpio_lock, flags); | |
828 | ||
829 | return status; | |
0eb4c6c2 AC |
830 | } |
831 | postcore_initcall(gpiolib_sysfs_init); |