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 = scnprintf(buf, PAGE_SIZE - 1, "%*pbl", n_events, bits);
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 	if (i == ddata->pdata->nbuttons) {
243 		error = -EINVAL;
244 		goto out;
245 	}
246 
247 	mutex_lock(&ddata->disable_lock);
248 
249 	for (i = 0; i < ddata->pdata->nbuttons; i++) {
250 		struct gpio_button_data *bdata = &ddata->data[i];
251 
252 		if (bdata->button->type != type)
253 			continue;
254 
255 		if (test_bit(bdata->button->code, bits))
256 			gpio_keys_disable_button(bdata);
257 		else
258 			gpio_keys_enable_button(bdata);
259 	}
260 
261 	mutex_unlock(&ddata->disable_lock);
262 
263 out:
264 	kfree(bits);
265 	return error;
266 }
267 
268 #define ATTR_SHOW_FN(name, type, only_disabled)				\
269 static ssize_t gpio_keys_show_##name(struct device *dev,		\
270 				     struct device_attribute *attr,	\
271 				     char *buf)				\
272 {									\
273 	struct platform_device *pdev = to_platform_device(dev);		\
274 	struct gpio_keys_drvdata *ddata = platform_get_drvdata(pdev);	\
275 									\
276 	return gpio_keys_attr_show_helper(ddata, buf,			\
277 					  type, only_disabled);		\
278 }
279 
280 ATTR_SHOW_FN(keys, EV_KEY, false);
281 ATTR_SHOW_FN(switches, EV_SW, false);
282 ATTR_SHOW_FN(disabled_keys, EV_KEY, true);
283 ATTR_SHOW_FN(disabled_switches, EV_SW, true);
284 
285 /*
286  * ATTRIBUTES:
287  *
288  * /sys/devices/platform/gpio-keys/keys [ro]
289  * /sys/devices/platform/gpio-keys/switches [ro]
290  */
291 static DEVICE_ATTR(keys, S_IRUGO, gpio_keys_show_keys, NULL);
292 static DEVICE_ATTR(switches, S_IRUGO, gpio_keys_show_switches, NULL);
293 
294 #define ATTR_STORE_FN(name, type)					\
295 static ssize_t gpio_keys_store_##name(struct device *dev,		\
296 				      struct device_attribute *attr,	\
297 				      const char *buf,			\
298 				      size_t count)			\
299 {									\
300 	struct platform_device *pdev = to_platform_device(dev);		\
301 	struct gpio_keys_drvdata *ddata = platform_get_drvdata(pdev);	\
302 	ssize_t error;							\
303 									\
304 	error = gpio_keys_attr_store_helper(ddata, buf, type);		\
305 	if (error)							\
306 		return error;						\
307 									\
308 	return count;							\
309 }
310 
311 ATTR_STORE_FN(disabled_keys, EV_KEY);
312 ATTR_STORE_FN(disabled_switches, EV_SW);
313 
314 /*
315  * ATTRIBUTES:
316  *
317  * /sys/devices/platform/gpio-keys/disabled_keys [rw]
318  * /sys/devices/platform/gpio-keys/disables_switches [rw]
319  */
320 static DEVICE_ATTR(disabled_keys, S_IWUSR | S_IRUGO,
321 		   gpio_keys_show_disabled_keys,
322 		   gpio_keys_store_disabled_keys);
323 static DEVICE_ATTR(disabled_switches, S_IWUSR | S_IRUGO,
324 		   gpio_keys_show_disabled_switches,
325 		   gpio_keys_store_disabled_switches);
326 
327 static struct attribute *gpio_keys_attrs[] = {
328 	&dev_attr_keys.attr,
329 	&dev_attr_switches.attr,
330 	&dev_attr_disabled_keys.attr,
331 	&dev_attr_disabled_switches.attr,
332 	NULL,
333 };
334 
335 static struct attribute_group gpio_keys_attr_group = {
336 	.attrs = gpio_keys_attrs,
337 };
338 
339 static void gpio_keys_gpio_report_event(struct gpio_button_data *bdata)
340 {
341 	const struct gpio_keys_button *button = bdata->button;
342 	struct input_dev *input = bdata->input;
343 	unsigned int type = button->type ?: EV_KEY;
344 	int state = (gpio_get_value_cansleep(button->gpio) ? 1 : 0) ^ button->active_low;
345 
346 	if (type == EV_ABS) {
347 		if (state)
348 			input_event(input, type, button->code, button->value);
349 	} else {
350 		input_event(input, type, button->code, !!state);
351 	}
352 	input_sync(input);
353 }
354 
355 static void gpio_keys_gpio_work_func(struct work_struct *work)
356 {
357 	struct gpio_button_data *bdata =
358 		container_of(work, struct gpio_button_data, work.work);
359 
360 	gpio_keys_gpio_report_event(bdata);
361 
362 	if (bdata->button->wakeup)
363 		pm_relax(bdata->input->dev.parent);
364 }
365 
366 static irqreturn_t gpio_keys_gpio_isr(int irq, void *dev_id)
367 {
368 	struct gpio_button_data *bdata = dev_id;
369 
370 	BUG_ON(irq != bdata->irq);
371 
372 	if (bdata->button->wakeup)
373 		pm_stay_awake(bdata->input->dev.parent);
374 
375 	mod_delayed_work(system_wq,
376 			 &bdata->work,
377 			 msecs_to_jiffies(bdata->software_debounce));
378 
379 	return IRQ_HANDLED;
380 }
381 
382 static void gpio_keys_irq_timer(unsigned long _data)
383 {
384 	struct gpio_button_data *bdata = (struct gpio_button_data *)_data;
385 	struct input_dev *input = bdata->input;
386 	unsigned long flags;
387 
388 	spin_lock_irqsave(&bdata->lock, flags);
389 	if (bdata->key_pressed) {
390 		input_event(input, EV_KEY, bdata->button->code, 0);
391 		input_sync(input);
392 		bdata->key_pressed = false;
393 	}
394 	spin_unlock_irqrestore(&bdata->lock, flags);
395 }
396 
397 static irqreturn_t gpio_keys_irq_isr(int irq, void *dev_id)
398 {
399 	struct gpio_button_data *bdata = dev_id;
400 	const struct gpio_keys_button *button = bdata->button;
401 	struct input_dev *input = bdata->input;
402 	unsigned long flags;
403 
404 	BUG_ON(irq != bdata->irq);
405 
406 	spin_lock_irqsave(&bdata->lock, flags);
407 
408 	if (!bdata->key_pressed) {
409 		if (bdata->button->wakeup)
410 			pm_wakeup_event(bdata->input->dev.parent, 0);
411 
412 		input_event(input, EV_KEY, button->code, 1);
413 		input_sync(input);
414 
415 		if (!bdata->release_delay) {
416 			input_event(input, EV_KEY, button->code, 0);
417 			input_sync(input);
418 			goto out;
419 		}
420 
421 		bdata->key_pressed = true;
422 	}
423 
424 	if (bdata->release_delay)
425 		mod_timer(&bdata->release_timer,
426 			jiffies + msecs_to_jiffies(bdata->release_delay));
427 out:
428 	spin_unlock_irqrestore(&bdata->lock, flags);
429 	return IRQ_HANDLED;
430 }
431 
432 static void gpio_keys_quiesce_key(void *data)
433 {
434 	struct gpio_button_data *bdata = data;
435 
436 	if (gpio_is_valid(bdata->button->gpio))
437 		cancel_delayed_work_sync(&bdata->work);
438 	else
439 		del_timer_sync(&bdata->release_timer);
440 }
441 
442 static int gpio_keys_setup_key(struct platform_device *pdev,
443 				struct input_dev *input,
444 				struct gpio_button_data *bdata,
445 				const struct gpio_keys_button *button)
446 {
447 	const char *desc = button->desc ? button->desc : "gpio_keys";
448 	struct device *dev = &pdev->dev;
449 	irq_handler_t isr;
450 	unsigned long irqflags;
451 	int irq;
452 	int error;
453 
454 	bdata->input = input;
455 	bdata->button = button;
456 	spin_lock_init(&bdata->lock);
457 
458 	if (gpio_is_valid(button->gpio)) {
459 
460 		error = devm_gpio_request_one(&pdev->dev, button->gpio,
461 					      GPIOF_IN, desc);
462 		if (error < 0) {
463 			dev_err(dev, "Failed to request GPIO %d, error %d\n",
464 				button->gpio, error);
465 			return error;
466 		}
467 
468 		if (button->debounce_interval) {
469 			error = gpio_set_debounce(button->gpio,
470 					button->debounce_interval * 1000);
471 			/* use timer if gpiolib doesn't provide debounce */
472 			if (error < 0)
473 				bdata->software_debounce =
474 						button->debounce_interval;
475 		}
476 
477 		if (button->irq) {
478 			bdata->irq = button->irq;
479 		} else {
480 			irq = gpio_to_irq(button->gpio);
481 			if (irq < 0) {
482 				error = irq;
483 				dev_err(dev,
484 					"Unable to get irq number for GPIO %d, error %d\n",
485 					button->gpio, error);
486 				return error;
487 			}
488 			bdata->irq = irq;
489 		}
490 
491 		INIT_DELAYED_WORK(&bdata->work, gpio_keys_gpio_work_func);
492 
493 		isr = gpio_keys_gpio_isr;
494 		irqflags = IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING;
495 
496 	} else {
497 		if (!button->irq) {
498 			dev_err(dev, "No IRQ specified\n");
499 			return -EINVAL;
500 		}
501 		bdata->irq = button->irq;
502 
503 		if (button->type && button->type != EV_KEY) {
504 			dev_err(dev, "Only EV_KEY allowed for IRQ buttons.\n");
505 			return -EINVAL;
506 		}
507 
508 		bdata->release_delay = button->debounce_interval;
509 		setup_timer(&bdata->release_timer,
510 			    gpio_keys_irq_timer, (unsigned long)bdata);
511 
512 		isr = gpio_keys_irq_isr;
513 		irqflags = 0;
514 	}
515 
516 	input_set_capability(input, button->type ?: EV_KEY, button->code);
517 
518 	/*
519 	 * Install custom action to cancel release timer and
520 	 * workqueue item.
521 	 */
522 	error = devm_add_action(&pdev->dev, gpio_keys_quiesce_key, bdata);
523 	if (error) {
524 		dev_err(&pdev->dev,
525 			"failed to register quiesce action, error: %d\n",
526 			error);
527 		return error;
528 	}
529 
530 	/*
531 	 * If platform has specified that the button can be disabled,
532 	 * we don't want it to share the interrupt line.
533 	 */
534 	if (!button->can_disable)
535 		irqflags |= IRQF_SHARED;
536 
537 	error = devm_request_any_context_irq(&pdev->dev, bdata->irq,
538 					     isr, irqflags, desc, bdata);
539 	if (error < 0) {
540 		dev_err(dev, "Unable to claim irq %d; error %d\n",
541 			bdata->irq, error);
542 		return error;
543 	}
544 
545 	return 0;
546 }
547 
548 static void gpio_keys_report_state(struct gpio_keys_drvdata *ddata)
549 {
550 	struct input_dev *input = ddata->input;
551 	int i;
552 
553 	for (i = 0; i < ddata->pdata->nbuttons; i++) {
554 		struct gpio_button_data *bdata = &ddata->data[i];
555 		if (gpio_is_valid(bdata->button->gpio))
556 			gpio_keys_gpio_report_event(bdata);
557 	}
558 	input_sync(input);
559 }
560 
561 static int gpio_keys_open(struct input_dev *input)
562 {
563 	struct gpio_keys_drvdata *ddata = input_get_drvdata(input);
564 	const struct gpio_keys_platform_data *pdata = ddata->pdata;
565 	int error;
566 
567 	if (pdata->enable) {
568 		error = pdata->enable(input->dev.parent);
569 		if (error)
570 			return error;
571 	}
572 
573 	/* Report current state of buttons that are connected to GPIOs */
574 	gpio_keys_report_state(ddata);
575 
576 	return 0;
577 }
578 
579 static void gpio_keys_close(struct input_dev *input)
580 {
581 	struct gpio_keys_drvdata *ddata = input_get_drvdata(input);
582 	const struct gpio_keys_platform_data *pdata = ddata->pdata;
583 
584 	if (pdata->disable)
585 		pdata->disable(input->dev.parent);
586 }
587 
588 /*
589  * Handlers for alternative sources of platform_data
590  */
591 
592 #ifdef CONFIG_OF
593 /*
594  * Translate OpenFirmware node properties into platform_data
595  */
596 static struct gpio_keys_platform_data *
597 gpio_keys_get_devtree_pdata(struct device *dev)
598 {
599 	struct device_node *node, *pp;
600 	struct gpio_keys_platform_data *pdata;
601 	struct gpio_keys_button *button;
602 	int error;
603 	int nbuttons;
604 	int i;
605 
606 	node = dev->of_node;
607 	if (!node)
608 		return ERR_PTR(-ENODEV);
609 
610 	nbuttons = of_get_child_count(node);
611 	if (nbuttons == 0)
612 		return ERR_PTR(-ENODEV);
613 
614 	pdata = devm_kzalloc(dev,
615 			     sizeof(*pdata) + nbuttons * sizeof(*button),
616 			     GFP_KERNEL);
617 	if (!pdata)
618 		return ERR_PTR(-ENOMEM);
619 
620 	pdata->buttons = (struct gpio_keys_button *)(pdata + 1);
621 	pdata->nbuttons = nbuttons;
622 
623 	pdata->rep = !!of_get_property(node, "autorepeat", NULL);
624 
625 	i = 0;
626 	for_each_child_of_node(node, pp) {
627 		enum of_gpio_flags flags;
628 
629 		button = &pdata->buttons[i++];
630 
631 		button->gpio = of_get_gpio_flags(pp, 0, &flags);
632 		if (button->gpio < 0) {
633 			error = button->gpio;
634 			if (error != -ENOENT) {
635 				if (error != -EPROBE_DEFER)
636 					dev_err(dev,
637 						"Failed to get gpio flags, error: %d\n",
638 						error);
639 				return ERR_PTR(error);
640 			}
641 		} else {
642 			button->active_low = flags & OF_GPIO_ACTIVE_LOW;
643 		}
644 
645 		button->irq = irq_of_parse_and_map(pp, 0);
646 
647 		if (!gpio_is_valid(button->gpio) && !button->irq) {
648 			dev_err(dev, "Found button without gpios or irqs\n");
649 			return ERR_PTR(-EINVAL);
650 		}
651 
652 		if (of_property_read_u32(pp, "linux,code", &button->code)) {
653 			dev_err(dev, "Button without keycode: 0x%x\n",
654 				button->gpio);
655 			return ERR_PTR(-EINVAL);
656 		}
657 
658 		button->desc = of_get_property(pp, "label", NULL);
659 
660 		if (of_property_read_u32(pp, "linux,input-type", &button->type))
661 			button->type = EV_KEY;
662 
663 		button->wakeup = of_property_read_bool(pp, "wakeup-source") ||
664 				 /* legacy name */
665 				 of_property_read_bool(pp, "gpio-key,wakeup");
666 
667 		button->can_disable = !!of_get_property(pp, "linux,can-disable", NULL);
668 
669 		if (of_property_read_u32(pp, "debounce-interval",
670 					 &button->debounce_interval))
671 			button->debounce_interval = 5;
672 	}
673 
674 	if (pdata->nbuttons == 0)
675 		return ERR_PTR(-EINVAL);
676 
677 	return pdata;
678 }
679 
680 static const struct of_device_id gpio_keys_of_match[] = {
681 	{ .compatible = "gpio-keys", },
682 	{ },
683 };
684 MODULE_DEVICE_TABLE(of, gpio_keys_of_match);
685 
686 #else
687 
688 static inline struct gpio_keys_platform_data *
689 gpio_keys_get_devtree_pdata(struct device *dev)
690 {
691 	return ERR_PTR(-ENODEV);
692 }
693 
694 #endif
695 
696 static int gpio_keys_probe(struct platform_device *pdev)
697 {
698 	struct device *dev = &pdev->dev;
699 	const struct gpio_keys_platform_data *pdata = dev_get_platdata(dev);
700 	struct gpio_keys_drvdata *ddata;
701 	struct input_dev *input;
702 	size_t size;
703 	int i, error;
704 	int wakeup = 0;
705 
706 	if (!pdata) {
707 		pdata = gpio_keys_get_devtree_pdata(dev);
708 		if (IS_ERR(pdata))
709 			return PTR_ERR(pdata);
710 	}
711 
712 	size = sizeof(struct gpio_keys_drvdata) +
713 			pdata->nbuttons * sizeof(struct gpio_button_data);
714 	ddata = devm_kzalloc(dev, size, GFP_KERNEL);
715 	if (!ddata) {
716 		dev_err(dev, "failed to allocate state\n");
717 		return -ENOMEM;
718 	}
719 
720 	input = devm_input_allocate_device(dev);
721 	if (!input) {
722 		dev_err(dev, "failed to allocate input device\n");
723 		return -ENOMEM;
724 	}
725 
726 	ddata->pdata = pdata;
727 	ddata->input = input;
728 	mutex_init(&ddata->disable_lock);
729 
730 	platform_set_drvdata(pdev, ddata);
731 	input_set_drvdata(input, ddata);
732 
733 	input->name = pdata->name ? : pdev->name;
734 	input->phys = "gpio-keys/input0";
735 	input->dev.parent = &pdev->dev;
736 	input->open = gpio_keys_open;
737 	input->close = gpio_keys_close;
738 
739 	input->id.bustype = BUS_HOST;
740 	input->id.vendor = 0x0001;
741 	input->id.product = 0x0001;
742 	input->id.version = 0x0100;
743 
744 	/* Enable auto repeat feature of Linux input subsystem */
745 	if (pdata->rep)
746 		__set_bit(EV_REP, input->evbit);
747 
748 	for (i = 0; i < pdata->nbuttons; i++) {
749 		const struct gpio_keys_button *button = &pdata->buttons[i];
750 		struct gpio_button_data *bdata = &ddata->data[i];
751 
752 		error = gpio_keys_setup_key(pdev, input, bdata, button);
753 		if (error)
754 			return error;
755 
756 		if (button->wakeup)
757 			wakeup = 1;
758 	}
759 
760 	error = sysfs_create_group(&pdev->dev.kobj, &gpio_keys_attr_group);
761 	if (error) {
762 		dev_err(dev, "Unable to export keys/switches, error: %d\n",
763 			error);
764 		return error;
765 	}
766 
767 	error = input_register_device(input);
768 	if (error) {
769 		dev_err(dev, "Unable to register input device, error: %d\n",
770 			error);
771 		goto err_remove_group;
772 	}
773 
774 	device_init_wakeup(&pdev->dev, wakeup);
775 
776 	return 0;
777 
778 err_remove_group:
779 	sysfs_remove_group(&pdev->dev.kobj, &gpio_keys_attr_group);
780 	return error;
781 }
782 
783 static int gpio_keys_remove(struct platform_device *pdev)
784 {
785 	sysfs_remove_group(&pdev->dev.kobj, &gpio_keys_attr_group);
786 
787 	device_init_wakeup(&pdev->dev, 0);
788 
789 	return 0;
790 }
791 
792 #ifdef CONFIG_PM_SLEEP
793 static int gpio_keys_suspend(struct device *dev)
794 {
795 	struct gpio_keys_drvdata *ddata = dev_get_drvdata(dev);
796 	struct input_dev *input = ddata->input;
797 	int i;
798 
799 	if (device_may_wakeup(dev)) {
800 		for (i = 0; i < ddata->pdata->nbuttons; i++) {
801 			struct gpio_button_data *bdata = &ddata->data[i];
802 			if (bdata->button->wakeup)
803 				enable_irq_wake(bdata->irq);
804 		}
805 	} else {
806 		mutex_lock(&input->mutex);
807 		if (input->users)
808 			gpio_keys_close(input);
809 		mutex_unlock(&input->mutex);
810 	}
811 
812 	return 0;
813 }
814 
815 static int gpio_keys_resume(struct device *dev)
816 {
817 	struct gpio_keys_drvdata *ddata = dev_get_drvdata(dev);
818 	struct input_dev *input = ddata->input;
819 	int error = 0;
820 	int i;
821 
822 	if (device_may_wakeup(dev)) {
823 		for (i = 0; i < ddata->pdata->nbuttons; i++) {
824 			struct gpio_button_data *bdata = &ddata->data[i];
825 			if (bdata->button->wakeup)
826 				disable_irq_wake(bdata->irq);
827 		}
828 	} else {
829 		mutex_lock(&input->mutex);
830 		if (input->users)
831 			error = gpio_keys_open(input);
832 		mutex_unlock(&input->mutex);
833 	}
834 
835 	if (error)
836 		return error;
837 
838 	gpio_keys_report_state(ddata);
839 	return 0;
840 }
841 #endif
842 
843 static SIMPLE_DEV_PM_OPS(gpio_keys_pm_ops, gpio_keys_suspend, gpio_keys_resume);
844 
845 static struct platform_driver gpio_keys_device_driver = {
846 	.probe		= gpio_keys_probe,
847 	.remove		= gpio_keys_remove,
848 	.driver		= {
849 		.name	= "gpio-keys",
850 		.pm	= &gpio_keys_pm_ops,
851 		.of_match_table = of_match_ptr(gpio_keys_of_match),
852 	}
853 };
854 
855 static int __init gpio_keys_init(void)
856 {
857 	return platform_driver_register(&gpio_keys_device_driver);
858 }
859 
860 static void __exit gpio_keys_exit(void)
861 {
862 	platform_driver_unregister(&gpio_keys_device_driver);
863 }
864 
865 late_initcall(gpio_keys_init);
866 module_exit(gpio_keys_exit);
867 
868 MODULE_LICENSE("GPL");
869 MODULE_AUTHOR("Phil Blundell <pb@handhelds.org>");
870 MODULE_DESCRIPTION("Keyboard driver for GPIOs");
871 MODULE_ALIAS("platform:gpio-keys");
872