1 /*
2  * Driver for keys on GPIO lines capable of generating interrupts.
3  *
4  * Copyright 2005 Phil Blundell
5  * Copyright 2010, 2011 David Jander <david@protonic.nl>
6  *
7  * This program is free software; you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License version 2 as
9  * published by the Free Software Foundation.
10  */
11 
12 #include <linux/module.h>
13 
14 #include <linux/init.h>
15 #include <linux/fs.h>
16 #include <linux/interrupt.h>
17 #include <linux/irq.h>
18 #include <linux/sched.h>
19 #include <linux/pm.h>
20 #include <linux/slab.h>
21 #include <linux/sysctl.h>
22 #include <linux/proc_fs.h>
23 #include <linux/delay.h>
24 #include <linux/platform_device.h>
25 #include <linux/input.h>
26 #include <linux/gpio_keys.h>
27 #include <linux/workqueue.h>
28 #include <linux/gpio.h>
29 #include <linux/of.h>
30 #include <linux/of_platform.h>
31 #include <linux/of_gpio.h>
32 #include <linux/of_irq.h>
33 #include <linux/spinlock.h>
34 
35 struct gpio_button_data {
36 	const struct gpio_keys_button *button;
37 	struct input_dev *input;
38 
39 	struct timer_list release_timer;
40 	unsigned int release_delay;	/* in msecs, for IRQ-only buttons */
41 
42 	struct delayed_work work;
43 	unsigned int software_debounce;	/* in msecs, for GPIO-driven buttons */
44 
45 	unsigned int irq;
46 	spinlock_t lock;
47 	bool disabled;
48 	bool key_pressed;
49 };
50 
51 struct gpio_keys_drvdata {
52 	const struct gpio_keys_platform_data *pdata;
53 	struct input_dev *input;
54 	struct mutex disable_lock;
55 	struct gpio_button_data data[0];
56 };
57 
58 /*
59  * SYSFS interface for enabling/disabling keys and switches:
60  *
61  * There are 4 attributes under /sys/devices/platform/gpio-keys/
62  *	keys [ro]              - bitmap of keys (EV_KEY) which can be
63  *	                         disabled
64  *	switches [ro]          - bitmap of switches (EV_SW) which can be
65  *	                         disabled
66  *	disabled_keys [rw]     - bitmap of keys currently disabled
67  *	disabled_switches [rw] - bitmap of switches currently disabled
68  *
69  * Userland can change these values and hence disable event generation
70  * for each key (or switch). Disabling a key means its interrupt line
71  * is disabled.
72  *
73  * For example, if we have following switches set up as gpio-keys:
74  *	SW_DOCK = 5
75  *	SW_CAMERA_LENS_COVER = 9
76  *	SW_KEYPAD_SLIDE = 10
77  *	SW_FRONT_PROXIMITY = 11
78  * This is read from switches:
79  *	11-9,5
80  * Next we want to disable proximity (11) and dock (5), we write:
81  *	11,5
82  * to file disabled_switches. Now proximity and dock IRQs are disabled.
83  * This can be verified by reading the file disabled_switches:
84  *	11,5
85  * If we now want to enable proximity (11) switch we write:
86  *	5
87  * to disabled_switches.
88  *
89  * We can disable only those keys which don't allow sharing the irq.
90  */
91 
92 /**
93  * get_n_events_by_type() - returns maximum number of events per @type
94  * @type: type of button (%EV_KEY, %EV_SW)
95  *
96  * Return value of this function can be used to allocate bitmap
97  * large enough to hold all bits for given type.
98  */
99 static inline int get_n_events_by_type(int type)
100 {
101 	BUG_ON(type != EV_SW && type != EV_KEY);
102 
103 	return (type == EV_KEY) ? KEY_CNT : SW_CNT;
104 }
105 
106 /**
107  * gpio_keys_disable_button() - disables given GPIO button
108  * @bdata: button data for button to be disabled
109  *
110  * Disables button pointed by @bdata. This is done by masking
111  * IRQ line. After this function is called, button won't generate
112  * input events anymore. Note that one can only disable buttons
113  * that don't share IRQs.
114  *
115  * Make sure that @bdata->disable_lock is locked when entering
116  * this function to avoid races when concurrent threads are
117  * disabling buttons at the same time.
118  */
119 static void gpio_keys_disable_button(struct gpio_button_data *bdata)
120 {
121 	if (!bdata->disabled) {
122 		/*
123 		 * Disable IRQ and associated timer/work structure.
124 		 */
125 		disable_irq(bdata->irq);
126 
127 		if (gpio_is_valid(bdata->button->gpio))
128 			cancel_delayed_work_sync(&bdata->work);
129 		else
130 			del_timer_sync(&bdata->release_timer);
131 
132 		bdata->disabled = true;
133 	}
134 }
135 
136 /**
137  * gpio_keys_enable_button() - enables given GPIO button
138  * @bdata: button data for button to be disabled
139  *
140  * Enables given button pointed by @bdata.
141  *
142  * Make sure that @bdata->disable_lock is locked when entering
143  * this function to avoid races with concurrent threads trying
144  * to enable the same button at the same time.
145  */
146 static void gpio_keys_enable_button(struct gpio_button_data *bdata)
147 {
148 	if (bdata->disabled) {
149 		enable_irq(bdata->irq);
150 		bdata->disabled = false;
151 	}
152 }
153 
154 /**
155  * gpio_keys_attr_show_helper() - fill in stringified bitmap of buttons
156  * @ddata: pointer to drvdata
157  * @buf: buffer where stringified bitmap is written
158  * @type: button type (%EV_KEY, %EV_SW)
159  * @only_disabled: does caller want only those buttons that are
160  *                 currently disabled or all buttons that can be
161  *                 disabled
162  *
163  * This function writes buttons that can be disabled to @buf. If
164  * @only_disabled is true, then @buf contains only those buttons
165  * that are currently disabled. Returns 0 on success or negative
166  * errno on failure.
167  */
168 static ssize_t gpio_keys_attr_show_helper(struct gpio_keys_drvdata *ddata,
169 					  char *buf, unsigned int type,
170 					  bool only_disabled)
171 {
172 	int n_events = get_n_events_by_type(type);
173 	unsigned long *bits;
174 	ssize_t ret;
175 	int i;
176 
177 	bits = kcalloc(BITS_TO_LONGS(n_events), sizeof(*bits), GFP_KERNEL);
178 	if (!bits)
179 		return -ENOMEM;
180 
181 	for (i = 0; i < ddata->pdata->nbuttons; i++) {
182 		struct gpio_button_data *bdata = &ddata->data[i];
183 
184 		if (bdata->button->type != type)
185 			continue;
186 
187 		if (only_disabled && !bdata->disabled)
188 			continue;
189 
190 		__set_bit(bdata->button->code, bits);
191 	}
192 
193 	ret = bitmap_scnlistprintf(buf, PAGE_SIZE - 2, bits, n_events);
194 	buf[ret++] = '\n';
195 	buf[ret] = '\0';
196 
197 	kfree(bits);
198 
199 	return ret;
200 }
201 
202 /**
203  * gpio_keys_attr_store_helper() - enable/disable buttons based on given bitmap
204  * @ddata: pointer to drvdata
205  * @buf: buffer from userspace that contains stringified bitmap
206  * @type: button type (%EV_KEY, %EV_SW)
207  *
208  * This function parses stringified bitmap from @buf and disables/enables
209  * GPIO buttons accordingly. Returns 0 on success and negative error
210  * on failure.
211  */
212 static ssize_t gpio_keys_attr_store_helper(struct gpio_keys_drvdata *ddata,
213 					   const char *buf, unsigned int type)
214 {
215 	int n_events = get_n_events_by_type(type);
216 	unsigned long *bits;
217 	ssize_t error;
218 	int i;
219 
220 	bits = kcalloc(BITS_TO_LONGS(n_events), sizeof(*bits), GFP_KERNEL);
221 	if (!bits)
222 		return -ENOMEM;
223 
224 	error = bitmap_parselist(buf, bits, n_events);
225 	if (error)
226 		goto out;
227 
228 	/* First validate */
229 	for (i = 0; i < ddata->pdata->nbuttons; i++) {
230 		struct gpio_button_data *bdata = &ddata->data[i];
231 
232 		if (bdata->button->type != type)
233 			continue;
234 
235 		if (test_bit(bdata->button->code, bits) &&
236 		    !bdata->button->can_disable) {
237 			error = -EINVAL;
238 			goto out;
239 		}
240 	}
241 
242 	mutex_lock(&ddata->disable_lock);
243 
244 	for (i = 0; i < ddata->pdata->nbuttons; i++) {
245 		struct gpio_button_data *bdata = &ddata->data[i];
246 
247 		if (bdata->button->type != type)
248 			continue;
249 
250 		if (test_bit(bdata->button->code, bits))
251 			gpio_keys_disable_button(bdata);
252 		else
253 			gpio_keys_enable_button(bdata);
254 	}
255 
256 	mutex_unlock(&ddata->disable_lock);
257 
258 out:
259 	kfree(bits);
260 	return error;
261 }
262 
263 #define ATTR_SHOW_FN(name, type, only_disabled)				\
264 static ssize_t gpio_keys_show_##name(struct device *dev,		\
265 				     struct device_attribute *attr,	\
266 				     char *buf)				\
267 {									\
268 	struct platform_device *pdev = to_platform_device(dev);		\
269 	struct gpio_keys_drvdata *ddata = platform_get_drvdata(pdev);	\
270 									\
271 	return gpio_keys_attr_show_helper(ddata, buf,			\
272 					  type, only_disabled);		\
273 }
274 
275 ATTR_SHOW_FN(keys, EV_KEY, false);
276 ATTR_SHOW_FN(switches, EV_SW, false);
277 ATTR_SHOW_FN(disabled_keys, EV_KEY, true);
278 ATTR_SHOW_FN(disabled_switches, EV_SW, true);
279 
280 /*
281  * ATTRIBUTES:
282  *
283  * /sys/devices/platform/gpio-keys/keys [ro]
284  * /sys/devices/platform/gpio-keys/switches [ro]
285  */
286 static DEVICE_ATTR(keys, S_IRUGO, gpio_keys_show_keys, NULL);
287 static DEVICE_ATTR(switches, S_IRUGO, gpio_keys_show_switches, NULL);
288 
289 #define ATTR_STORE_FN(name, type)					\
290 static ssize_t gpio_keys_store_##name(struct device *dev,		\
291 				      struct device_attribute *attr,	\
292 				      const char *buf,			\
293 				      size_t count)			\
294 {									\
295 	struct platform_device *pdev = to_platform_device(dev);		\
296 	struct gpio_keys_drvdata *ddata = platform_get_drvdata(pdev);	\
297 	ssize_t error;							\
298 									\
299 	error = gpio_keys_attr_store_helper(ddata, buf, type);		\
300 	if (error)							\
301 		return error;						\
302 									\
303 	return count;							\
304 }
305 
306 ATTR_STORE_FN(disabled_keys, EV_KEY);
307 ATTR_STORE_FN(disabled_switches, EV_SW);
308 
309 /*
310  * ATTRIBUTES:
311  *
312  * /sys/devices/platform/gpio-keys/disabled_keys [rw]
313  * /sys/devices/platform/gpio-keys/disables_switches [rw]
314  */
315 static DEVICE_ATTR(disabled_keys, S_IWUSR | S_IRUGO,
316 		   gpio_keys_show_disabled_keys,
317 		   gpio_keys_store_disabled_keys);
318 static DEVICE_ATTR(disabled_switches, S_IWUSR | S_IRUGO,
319 		   gpio_keys_show_disabled_switches,
320 		   gpio_keys_store_disabled_switches);
321 
322 static struct attribute *gpio_keys_attrs[] = {
323 	&dev_attr_keys.attr,
324 	&dev_attr_switches.attr,
325 	&dev_attr_disabled_keys.attr,
326 	&dev_attr_disabled_switches.attr,
327 	NULL,
328 };
329 
330 static struct attribute_group gpio_keys_attr_group = {
331 	.attrs = gpio_keys_attrs,
332 };
333 
334 static void gpio_keys_gpio_report_event(struct gpio_button_data *bdata)
335 {
336 	const struct gpio_keys_button *button = bdata->button;
337 	struct input_dev *input = bdata->input;
338 	unsigned int type = button->type ?: EV_KEY;
339 	int state = (gpio_get_value_cansleep(button->gpio) ? 1 : 0) ^ button->active_low;
340 
341 	if (type == EV_ABS) {
342 		if (state)
343 			input_event(input, type, button->code, button->value);
344 	} else {
345 		input_event(input, type, button->code, !!state);
346 	}
347 	input_sync(input);
348 }
349 
350 static void gpio_keys_gpio_work_func(struct work_struct *work)
351 {
352 	struct gpio_button_data *bdata =
353 		container_of(work, struct gpio_button_data, work.work);
354 
355 	gpio_keys_gpio_report_event(bdata);
356 
357 	if (bdata->button->wakeup)
358 		pm_relax(bdata->input->dev.parent);
359 }
360 
361 static irqreturn_t gpio_keys_gpio_isr(int irq, void *dev_id)
362 {
363 	struct gpio_button_data *bdata = dev_id;
364 
365 	BUG_ON(irq != bdata->irq);
366 
367 	if (bdata->button->wakeup)
368 		pm_stay_awake(bdata->input->dev.parent);
369 
370 	mod_delayed_work(system_wq,
371 			 &bdata->work,
372 			 msecs_to_jiffies(bdata->software_debounce));
373 
374 	return IRQ_HANDLED;
375 }
376 
377 static void gpio_keys_irq_timer(unsigned long _data)
378 {
379 	struct gpio_button_data *bdata = (struct gpio_button_data *)_data;
380 	struct input_dev *input = bdata->input;
381 	unsigned long flags;
382 
383 	spin_lock_irqsave(&bdata->lock, flags);
384 	if (bdata->key_pressed) {
385 		input_event(input, EV_KEY, bdata->button->code, 0);
386 		input_sync(input);
387 		bdata->key_pressed = false;
388 	}
389 	spin_unlock_irqrestore(&bdata->lock, flags);
390 }
391 
392 static irqreturn_t gpio_keys_irq_isr(int irq, void *dev_id)
393 {
394 	struct gpio_button_data *bdata = dev_id;
395 	const struct gpio_keys_button *button = bdata->button;
396 	struct input_dev *input = bdata->input;
397 	unsigned long flags;
398 
399 	BUG_ON(irq != bdata->irq);
400 
401 	spin_lock_irqsave(&bdata->lock, flags);
402 
403 	if (!bdata->key_pressed) {
404 		if (bdata->button->wakeup)
405 			pm_wakeup_event(bdata->input->dev.parent, 0);
406 
407 		input_event(input, EV_KEY, button->code, 1);
408 		input_sync(input);
409 
410 		if (!bdata->release_delay) {
411 			input_event(input, EV_KEY, button->code, 0);
412 			input_sync(input);
413 			goto out;
414 		}
415 
416 		bdata->key_pressed = true;
417 	}
418 
419 	if (bdata->release_delay)
420 		mod_timer(&bdata->release_timer,
421 			jiffies + msecs_to_jiffies(bdata->release_delay));
422 out:
423 	spin_unlock_irqrestore(&bdata->lock, flags);
424 	return IRQ_HANDLED;
425 }
426 
427 static void gpio_keys_quiesce_key(void *data)
428 {
429 	struct gpio_button_data *bdata = data;
430 
431 	if (gpio_is_valid(bdata->button->gpio))
432 		cancel_delayed_work_sync(&bdata->work);
433 	else
434 		del_timer_sync(&bdata->release_timer);
435 }
436 
437 static int gpio_keys_setup_key(struct platform_device *pdev,
438 				struct input_dev *input,
439 				struct gpio_button_data *bdata,
440 				const struct gpio_keys_button *button)
441 {
442 	const char *desc = button->desc ? button->desc : "gpio_keys";
443 	struct device *dev = &pdev->dev;
444 	irq_handler_t isr;
445 	unsigned long irqflags;
446 	int irq;
447 	int error;
448 
449 	bdata->input = input;
450 	bdata->button = button;
451 	spin_lock_init(&bdata->lock);
452 
453 	if (gpio_is_valid(button->gpio)) {
454 
455 		error = devm_gpio_request_one(&pdev->dev, button->gpio,
456 					      GPIOF_IN, desc);
457 		if (error < 0) {
458 			dev_err(dev, "Failed to request GPIO %d, error %d\n",
459 				button->gpio, error);
460 			return error;
461 		}
462 
463 		if (button->debounce_interval) {
464 			error = gpio_set_debounce(button->gpio,
465 					button->debounce_interval * 1000);
466 			/* use timer if gpiolib doesn't provide debounce */
467 			if (error < 0)
468 				bdata->software_debounce =
469 						button->debounce_interval;
470 		}
471 
472 		if (button->irq) {
473 			bdata->irq = button->irq;
474 		} else {
475 			irq = gpio_to_irq(button->gpio);
476 			if (irq < 0) {
477 				error = irq;
478 				dev_err(dev,
479 					"Unable to get irq number for GPIO %d, error %d\n",
480 					button->gpio, error);
481 				return error;
482 			}
483 			bdata->irq = irq;
484 		}
485 
486 		INIT_DELAYED_WORK(&bdata->work, gpio_keys_gpio_work_func);
487 
488 		isr = gpio_keys_gpio_isr;
489 		irqflags = IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING;
490 
491 	} else {
492 		if (!button->irq) {
493 			dev_err(dev, "No IRQ specified\n");
494 			return -EINVAL;
495 		}
496 		bdata->irq = button->irq;
497 
498 		if (button->type && button->type != EV_KEY) {
499 			dev_err(dev, "Only EV_KEY allowed for IRQ buttons.\n");
500 			return -EINVAL;
501 		}
502 
503 		bdata->release_delay = button->debounce_interval;
504 		setup_timer(&bdata->release_timer,
505 			    gpio_keys_irq_timer, (unsigned long)bdata);
506 
507 		isr = gpio_keys_irq_isr;
508 		irqflags = 0;
509 	}
510 
511 	input_set_capability(input, button->type ?: EV_KEY, button->code);
512 
513 	/*
514 	 * Install custom action to cancel release timer and
515 	 * workqueue item.
516 	 */
517 	error = devm_add_action(&pdev->dev, gpio_keys_quiesce_key, bdata);
518 	if (error) {
519 		dev_err(&pdev->dev,
520 			"failed to register quiesce action, error: %d\n",
521 			error);
522 		return error;
523 	}
524 
525 	/*
526 	 * If platform has specified that the button can be disabled,
527 	 * we don't want it to share the interrupt line.
528 	 */
529 	if (!button->can_disable)
530 		irqflags |= IRQF_SHARED;
531 
532 	error = devm_request_any_context_irq(&pdev->dev, bdata->irq,
533 					     isr, irqflags, desc, bdata);
534 	if (error < 0) {
535 		dev_err(dev, "Unable to claim irq %d; error %d\n",
536 			bdata->irq, error);
537 		return error;
538 	}
539 
540 	return 0;
541 }
542 
543 static void gpio_keys_report_state(struct gpio_keys_drvdata *ddata)
544 {
545 	struct input_dev *input = ddata->input;
546 	int i;
547 
548 	for (i = 0; i < ddata->pdata->nbuttons; i++) {
549 		struct gpio_button_data *bdata = &ddata->data[i];
550 		if (gpio_is_valid(bdata->button->gpio))
551 			gpio_keys_gpio_report_event(bdata);
552 	}
553 	input_sync(input);
554 }
555 
556 static int gpio_keys_open(struct input_dev *input)
557 {
558 	struct gpio_keys_drvdata *ddata = input_get_drvdata(input);
559 	const struct gpio_keys_platform_data *pdata = ddata->pdata;
560 	int error;
561 
562 	if (pdata->enable) {
563 		error = pdata->enable(input->dev.parent);
564 		if (error)
565 			return error;
566 	}
567 
568 	/* Report current state of buttons that are connected to GPIOs */
569 	gpio_keys_report_state(ddata);
570 
571 	return 0;
572 }
573 
574 static void gpio_keys_close(struct input_dev *input)
575 {
576 	struct gpio_keys_drvdata *ddata = input_get_drvdata(input);
577 	const struct gpio_keys_platform_data *pdata = ddata->pdata;
578 
579 	if (pdata->disable)
580 		pdata->disable(input->dev.parent);
581 }
582 
583 /*
584  * Handlers for alternative sources of platform_data
585  */
586 
587 #ifdef CONFIG_OF
588 /*
589  * Translate OpenFirmware node properties into platform_data
590  */
591 static struct gpio_keys_platform_data *
592 gpio_keys_get_devtree_pdata(struct device *dev)
593 {
594 	struct device_node *node, *pp;
595 	struct gpio_keys_platform_data *pdata;
596 	struct gpio_keys_button *button;
597 	int error;
598 	int nbuttons;
599 	int i;
600 
601 	node = dev->of_node;
602 	if (!node)
603 		return ERR_PTR(-ENODEV);
604 
605 	nbuttons = of_get_child_count(node);
606 	if (nbuttons == 0)
607 		return ERR_PTR(-ENODEV);
608 
609 	pdata = devm_kzalloc(dev,
610 			     sizeof(*pdata) + nbuttons * sizeof(*button),
611 			     GFP_KERNEL);
612 	if (!pdata)
613 		return ERR_PTR(-ENOMEM);
614 
615 	pdata->buttons = (struct gpio_keys_button *)(pdata + 1);
616 	pdata->nbuttons = nbuttons;
617 
618 	pdata->rep = !!of_get_property(node, "autorepeat", NULL);
619 
620 	i = 0;
621 	for_each_child_of_node(node, pp) {
622 		enum of_gpio_flags flags;
623 
624 		button = &pdata->buttons[i++];
625 
626 		button->gpio = of_get_gpio_flags(pp, 0, &flags);
627 		if (button->gpio < 0) {
628 			error = button->gpio;
629 			if (error != -ENOENT) {
630 				if (error != -EPROBE_DEFER)
631 					dev_err(dev,
632 						"Failed to get gpio flags, error: %d\n",
633 						error);
634 				return ERR_PTR(error);
635 			}
636 		} else {
637 			button->active_low = flags & OF_GPIO_ACTIVE_LOW;
638 		}
639 
640 		button->irq = irq_of_parse_and_map(pp, 0);
641 
642 		if (!gpio_is_valid(button->gpio) && !button->irq) {
643 			dev_err(dev, "Found button without gpios or irqs\n");
644 			return ERR_PTR(-EINVAL);
645 		}
646 
647 		if (of_property_read_u32(pp, "linux,code", &button->code)) {
648 			dev_err(dev, "Button without keycode: 0x%x\n",
649 				button->gpio);
650 			return ERR_PTR(-EINVAL);
651 		}
652 
653 		button->desc = of_get_property(pp, "label", NULL);
654 
655 		if (of_property_read_u32(pp, "linux,input-type", &button->type))
656 			button->type = EV_KEY;
657 
658 		button->wakeup = !!of_get_property(pp, "gpio-key,wakeup", NULL);
659 
660 		button->can_disable = !!of_get_property(pp, "linux,can-disable", NULL);
661 
662 		if (of_property_read_u32(pp, "debounce-interval",
663 					 &button->debounce_interval))
664 			button->debounce_interval = 5;
665 	}
666 
667 	if (pdata->nbuttons == 0)
668 		return ERR_PTR(-EINVAL);
669 
670 	return pdata;
671 }
672 
673 static const struct of_device_id gpio_keys_of_match[] = {
674 	{ .compatible = "gpio-keys", },
675 	{ },
676 };
677 MODULE_DEVICE_TABLE(of, gpio_keys_of_match);
678 
679 #else
680 
681 static inline struct gpio_keys_platform_data *
682 gpio_keys_get_devtree_pdata(struct device *dev)
683 {
684 	return ERR_PTR(-ENODEV);
685 }
686 
687 #endif
688 
689 static int gpio_keys_probe(struct platform_device *pdev)
690 {
691 	struct device *dev = &pdev->dev;
692 	const struct gpio_keys_platform_data *pdata = dev_get_platdata(dev);
693 	struct gpio_keys_drvdata *ddata;
694 	struct input_dev *input;
695 	size_t size;
696 	int i, error;
697 	int wakeup = 0;
698 
699 	if (!pdata) {
700 		pdata = gpio_keys_get_devtree_pdata(dev);
701 		if (IS_ERR(pdata))
702 			return PTR_ERR(pdata);
703 	}
704 
705 	size = sizeof(struct gpio_keys_drvdata) +
706 			pdata->nbuttons * sizeof(struct gpio_button_data);
707 	ddata = devm_kzalloc(dev, size, GFP_KERNEL);
708 	if (!ddata) {
709 		dev_err(dev, "failed to allocate state\n");
710 		return -ENOMEM;
711 	}
712 
713 	input = devm_input_allocate_device(dev);
714 	if (!input) {
715 		dev_err(dev, "failed to allocate input device\n");
716 		return -ENOMEM;
717 	}
718 
719 	ddata->pdata = pdata;
720 	ddata->input = input;
721 	mutex_init(&ddata->disable_lock);
722 
723 	platform_set_drvdata(pdev, ddata);
724 	input_set_drvdata(input, ddata);
725 
726 	input->name = pdata->name ? : pdev->name;
727 	input->phys = "gpio-keys/input0";
728 	input->dev.parent = &pdev->dev;
729 	input->open = gpio_keys_open;
730 	input->close = gpio_keys_close;
731 
732 	input->id.bustype = BUS_HOST;
733 	input->id.vendor = 0x0001;
734 	input->id.product = 0x0001;
735 	input->id.version = 0x0100;
736 
737 	/* Enable auto repeat feature of Linux input subsystem */
738 	if (pdata->rep)
739 		__set_bit(EV_REP, input->evbit);
740 
741 	for (i = 0; i < pdata->nbuttons; i++) {
742 		const struct gpio_keys_button *button = &pdata->buttons[i];
743 		struct gpio_button_data *bdata = &ddata->data[i];
744 
745 		error = gpio_keys_setup_key(pdev, input, bdata, button);
746 		if (error)
747 			return error;
748 
749 		if (button->wakeup)
750 			wakeup = 1;
751 	}
752 
753 	error = sysfs_create_group(&pdev->dev.kobj, &gpio_keys_attr_group);
754 	if (error) {
755 		dev_err(dev, "Unable to export keys/switches, error: %d\n",
756 			error);
757 		return error;
758 	}
759 
760 	error = input_register_device(input);
761 	if (error) {
762 		dev_err(dev, "Unable to register input device, error: %d\n",
763 			error);
764 		goto err_remove_group;
765 	}
766 
767 	device_init_wakeup(&pdev->dev, wakeup);
768 
769 	return 0;
770 
771 err_remove_group:
772 	sysfs_remove_group(&pdev->dev.kobj, &gpio_keys_attr_group);
773 	return error;
774 }
775 
776 static int gpio_keys_remove(struct platform_device *pdev)
777 {
778 	sysfs_remove_group(&pdev->dev.kobj, &gpio_keys_attr_group);
779 
780 	device_init_wakeup(&pdev->dev, 0);
781 
782 	return 0;
783 }
784 
785 #ifdef CONFIG_PM_SLEEP
786 static int gpio_keys_suspend(struct device *dev)
787 {
788 	struct gpio_keys_drvdata *ddata = dev_get_drvdata(dev);
789 	struct input_dev *input = ddata->input;
790 	int i;
791 
792 	if (device_may_wakeup(dev)) {
793 		for (i = 0; i < ddata->pdata->nbuttons; i++) {
794 			struct gpio_button_data *bdata = &ddata->data[i];
795 			if (bdata->button->wakeup)
796 				enable_irq_wake(bdata->irq);
797 		}
798 	} else {
799 		mutex_lock(&input->mutex);
800 		if (input->users)
801 			gpio_keys_close(input);
802 		mutex_unlock(&input->mutex);
803 	}
804 
805 	return 0;
806 }
807 
808 static int gpio_keys_resume(struct device *dev)
809 {
810 	struct gpio_keys_drvdata *ddata = dev_get_drvdata(dev);
811 	struct input_dev *input = ddata->input;
812 	int error = 0;
813 	int i;
814 
815 	if (device_may_wakeup(dev)) {
816 		for (i = 0; i < ddata->pdata->nbuttons; i++) {
817 			struct gpio_button_data *bdata = &ddata->data[i];
818 			if (bdata->button->wakeup)
819 				disable_irq_wake(bdata->irq);
820 		}
821 	} else {
822 		mutex_lock(&input->mutex);
823 		if (input->users)
824 			error = gpio_keys_open(input);
825 		mutex_unlock(&input->mutex);
826 	}
827 
828 	if (error)
829 		return error;
830 
831 	gpio_keys_report_state(ddata);
832 	return 0;
833 }
834 #endif
835 
836 static SIMPLE_DEV_PM_OPS(gpio_keys_pm_ops, gpio_keys_suspend, gpio_keys_resume);
837 
838 static struct platform_driver gpio_keys_device_driver = {
839 	.probe		= gpio_keys_probe,
840 	.remove		= gpio_keys_remove,
841 	.driver		= {
842 		.name	= "gpio-keys",
843 		.pm	= &gpio_keys_pm_ops,
844 		.of_match_table = of_match_ptr(gpio_keys_of_match),
845 	}
846 };
847 
848 static int __init gpio_keys_init(void)
849 {
850 	return platform_driver_register(&gpio_keys_device_driver);
851 }
852 
853 static void __exit gpio_keys_exit(void)
854 {
855 	platform_driver_unregister(&gpio_keys_device_driver);
856 }
857 
858 late_initcall(gpio_keys_init);
859 module_exit(gpio_keys_exit);
860 
861 MODULE_LICENSE("GPL");
862 MODULE_AUTHOR("Phil Blundell <pb@handhelds.org>");
863 MODULE_DESCRIPTION("Keyboard driver for GPIOs");
864 MODULE_ALIAS("platform:gpio-keys");
865