2 * Driver for keys on GPIO lines capable of generating interrupts.
4 * Copyright 2005 Phil Blundell
5 * Copyright 2010, 2011 David Jander <david@protonic.nl>
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.
12 #include <linux/module.h>
14 #include <linux/init.h>
16 #include <linux/interrupt.h>
17 #include <linux/irq.h>
18 #include <linux/sched.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_platform.h>
30 #include <linux/of_gpio.h>
31 #include <linux/spinlock.h>
33 struct gpio_button_data {
34 const struct gpio_keys_button *button;
35 struct input_dev *input;
36 struct timer_list timer;
37 struct work_struct work;
38 unsigned int timer_debounce; /* in msecs */
45 struct gpio_keys_drvdata {
46 const struct gpio_keys_platform_data *pdata;
47 struct input_dev *input;
48 struct mutex disable_lock;
49 struct gpio_button_data data[0];
53 * SYSFS interface for enabling/disabling keys and switches:
55 * There are 4 attributes under /sys/devices/platform/gpio-keys/
56 * keys [ro] - bitmap of keys (EV_KEY) which can be
58 * switches [ro] - bitmap of switches (EV_SW) which can be
60 * disabled_keys [rw] - bitmap of keys currently disabled
61 * disabled_switches [rw] - bitmap of switches currently disabled
63 * Userland can change these values and hence disable event generation
64 * for each key (or switch). Disabling a key means its interrupt line
67 * For example, if we have following switches set up as gpio-keys:
69 * SW_CAMERA_LENS_COVER = 9
70 * SW_KEYPAD_SLIDE = 10
71 * SW_FRONT_PROXIMITY = 11
72 * This is read from switches:
74 * Next we want to disable proximity (11) and dock (5), we write:
76 * to file disabled_switches. Now proximity and dock IRQs are disabled.
77 * This can be verified by reading the file disabled_switches:
79 * If we now want to enable proximity (11) switch we write:
81 * to disabled_switches.
83 * We can disable only those keys which don't allow sharing the irq.
87 * get_n_events_by_type() - returns maximum number of events per @type
88 * @type: type of button (%EV_KEY, %EV_SW)
90 * Return value of this function can be used to allocate bitmap
91 * large enough to hold all bits for given type.
93 static inline int get_n_events_by_type(int type)
95 BUG_ON(type != EV_SW && type != EV_KEY);
97 return (type == EV_KEY) ? KEY_CNT : SW_CNT;
101 * gpio_keys_disable_button() - disables given GPIO button
102 * @bdata: button data for button to be disabled
104 * Disables button pointed by @bdata. This is done by masking
105 * IRQ line. After this function is called, button won't generate
106 * input events anymore. Note that one can only disable buttons
107 * that don't share IRQs.
109 * Make sure that @bdata->disable_lock is locked when entering
110 * this function to avoid races when concurrent threads are
111 * disabling buttons at the same time.
113 static void gpio_keys_disable_button(struct gpio_button_data *bdata)
115 if (!bdata->disabled) {
117 * Disable IRQ and possible debouncing timer.
119 disable_irq(bdata->irq);
120 if (bdata->timer_debounce)
121 del_timer_sync(&bdata->timer);
123 bdata->disabled = true;
128 * gpio_keys_enable_button() - enables given GPIO button
129 * @bdata: button data for button to be disabled
131 * Enables given button pointed by @bdata.
133 * Make sure that @bdata->disable_lock is locked when entering
134 * this function to avoid races with concurrent threads trying
135 * to enable the same button at the same time.
137 static void gpio_keys_enable_button(struct gpio_button_data *bdata)
139 if (bdata->disabled) {
140 enable_irq(bdata->irq);
141 bdata->disabled = false;
146 * gpio_keys_attr_show_helper() - fill in stringified bitmap of buttons
147 * @ddata: pointer to drvdata
148 * @buf: buffer where stringified bitmap is written
149 * @type: button type (%EV_KEY, %EV_SW)
150 * @only_disabled: does caller want only those buttons that are
151 * currently disabled or all buttons that can be
154 * This function writes buttons that can be disabled to @buf. If
155 * @only_disabled is true, then @buf contains only those buttons
156 * that are currently disabled. Returns 0 on success or negative
159 static ssize_t gpio_keys_attr_show_helper(struct gpio_keys_drvdata *ddata,
160 char *buf, unsigned int type,
163 int n_events = get_n_events_by_type(type);
168 bits = kcalloc(BITS_TO_LONGS(n_events), sizeof(*bits), GFP_KERNEL);
172 for (i = 0; i < ddata->pdata->nbuttons; i++) {
173 struct gpio_button_data *bdata = &ddata->data[i];
175 if (bdata->button->type != type)
178 if (only_disabled && !bdata->disabled)
181 __set_bit(bdata->button->code, bits);
184 ret = bitmap_scnlistprintf(buf, PAGE_SIZE - 2, bits, n_events);
194 * gpio_keys_attr_store_helper() - enable/disable buttons based on given bitmap
195 * @ddata: pointer to drvdata
196 * @buf: buffer from userspace that contains stringified bitmap
197 * @type: button type (%EV_KEY, %EV_SW)
199 * This function parses stringified bitmap from @buf and disables/enables
200 * GPIO buttons accordingly. Returns 0 on success and negative error
203 static ssize_t gpio_keys_attr_store_helper(struct gpio_keys_drvdata *ddata,
204 const char *buf, unsigned int type)
206 int n_events = get_n_events_by_type(type);
211 bits = kcalloc(BITS_TO_LONGS(n_events), sizeof(*bits), GFP_KERNEL);
215 error = bitmap_parselist(buf, bits, n_events);
220 for (i = 0; i < ddata->pdata->nbuttons; i++) {
221 struct gpio_button_data *bdata = &ddata->data[i];
223 if (bdata->button->type != type)
226 if (test_bit(bdata->button->code, bits) &&
227 !bdata->button->can_disable) {
233 mutex_lock(&ddata->disable_lock);
235 for (i = 0; i < ddata->pdata->nbuttons; i++) {
236 struct gpio_button_data *bdata = &ddata->data[i];
238 if (bdata->button->type != type)
241 if (test_bit(bdata->button->code, bits))
242 gpio_keys_disable_button(bdata);
244 gpio_keys_enable_button(bdata);
247 mutex_unlock(&ddata->disable_lock);
254 #define ATTR_SHOW_FN(name, type, only_disabled) \
255 static ssize_t gpio_keys_show_##name(struct device *dev, \
256 struct device_attribute *attr, \
259 struct platform_device *pdev = to_platform_device(dev); \
260 struct gpio_keys_drvdata *ddata = platform_get_drvdata(pdev); \
262 return gpio_keys_attr_show_helper(ddata, buf, \
263 type, only_disabled); \
266 ATTR_SHOW_FN(keys, EV_KEY, false);
267 ATTR_SHOW_FN(switches, EV_SW, false);
268 ATTR_SHOW_FN(disabled_keys, EV_KEY, true);
269 ATTR_SHOW_FN(disabled_switches, EV_SW, true);
274 * /sys/devices/platform/gpio-keys/keys [ro]
275 * /sys/devices/platform/gpio-keys/switches [ro]
277 static DEVICE_ATTR(keys, S_IRUGO, gpio_keys_show_keys, NULL);
278 static DEVICE_ATTR(switches, S_IRUGO, gpio_keys_show_switches, NULL);
280 #define ATTR_STORE_FN(name, type) \
281 static ssize_t gpio_keys_store_##name(struct device *dev, \
282 struct device_attribute *attr, \
286 struct platform_device *pdev = to_platform_device(dev); \
287 struct gpio_keys_drvdata *ddata = platform_get_drvdata(pdev); \
290 error = gpio_keys_attr_store_helper(ddata, buf, type); \
297 ATTR_STORE_FN(disabled_keys, EV_KEY);
298 ATTR_STORE_FN(disabled_switches, EV_SW);
303 * /sys/devices/platform/gpio-keys/disabled_keys [rw]
304 * /sys/devices/platform/gpio-keys/disables_switches [rw]
306 static DEVICE_ATTR(disabled_keys, S_IWUSR | S_IRUGO,
307 gpio_keys_show_disabled_keys,
308 gpio_keys_store_disabled_keys);
309 static DEVICE_ATTR(disabled_switches, S_IWUSR | S_IRUGO,
310 gpio_keys_show_disabled_switches,
311 gpio_keys_store_disabled_switches);
313 static struct attribute *gpio_keys_attrs[] = {
315 &dev_attr_switches.attr,
316 &dev_attr_disabled_keys.attr,
317 &dev_attr_disabled_switches.attr,
321 static struct attribute_group gpio_keys_attr_group = {
322 .attrs = gpio_keys_attrs,
325 static void gpio_keys_gpio_report_event(struct gpio_button_data *bdata)
327 const struct gpio_keys_button *button = bdata->button;
328 struct input_dev *input = bdata->input;
329 unsigned int type = button->type ?: EV_KEY;
330 int state = (gpio_get_value_cansleep(button->gpio) ? 1 : 0) ^ button->active_low;
332 if (type == EV_ABS) {
334 input_event(input, type, button->code, button->value);
336 input_event(input, type, button->code, !!state);
341 static void gpio_keys_gpio_work_func(struct work_struct *work)
343 struct gpio_button_data *bdata =
344 container_of(work, struct gpio_button_data, work);
346 gpio_keys_gpio_report_event(bdata);
348 if (bdata->button->wakeup)
349 pm_relax(bdata->input->dev.parent);
352 static void gpio_keys_gpio_timer(unsigned long _data)
354 struct gpio_button_data *bdata = (struct gpio_button_data *)_data;
356 schedule_work(&bdata->work);
359 static irqreturn_t gpio_keys_gpio_isr(int irq, void *dev_id)
361 struct gpio_button_data *bdata = dev_id;
363 BUG_ON(irq != bdata->irq);
365 if (bdata->button->wakeup)
366 pm_stay_awake(bdata->input->dev.parent);
367 if (bdata->timer_debounce)
368 mod_timer(&bdata->timer,
369 jiffies + msecs_to_jiffies(bdata->timer_debounce));
371 schedule_work(&bdata->work);
376 static void gpio_keys_irq_timer(unsigned long _data)
378 struct gpio_button_data *bdata = (struct gpio_button_data *)_data;
379 struct input_dev *input = bdata->input;
382 spin_lock_irqsave(&bdata->lock, flags);
383 if (bdata->key_pressed) {
384 input_event(input, EV_KEY, bdata->button->code, 0);
386 bdata->key_pressed = false;
388 spin_unlock_irqrestore(&bdata->lock, flags);
391 static irqreturn_t gpio_keys_irq_isr(int irq, void *dev_id)
393 struct gpio_button_data *bdata = dev_id;
394 const struct gpio_keys_button *button = bdata->button;
395 struct input_dev *input = bdata->input;
398 BUG_ON(irq != bdata->irq);
400 spin_lock_irqsave(&bdata->lock, flags);
402 if (!bdata->key_pressed) {
403 if (bdata->button->wakeup)
404 pm_wakeup_event(bdata->input->dev.parent, 0);
406 input_event(input, EV_KEY, button->code, 1);
409 if (!bdata->timer_debounce) {
410 input_event(input, EV_KEY, button->code, 0);
415 bdata->key_pressed = true;
418 if (bdata->timer_debounce)
419 mod_timer(&bdata->timer,
420 jiffies + msecs_to_jiffies(bdata->timer_debounce));
422 spin_unlock_irqrestore(&bdata->lock, flags);
426 static int __devinit gpio_keys_setup_key(struct platform_device *pdev,
427 struct input_dev *input,
428 struct gpio_button_data *bdata,
429 const struct gpio_keys_button *button)
431 const char *desc = button->desc ? button->desc : "gpio_keys";
432 struct device *dev = &pdev->dev;
434 unsigned long irqflags;
437 bdata->input = input;
438 bdata->button = button;
439 spin_lock_init(&bdata->lock);
441 if (gpio_is_valid(button->gpio)) {
443 error = gpio_request(button->gpio, desc);
445 dev_err(dev, "Failed to request GPIO %d, error %d\n",
446 button->gpio, error);
450 error = gpio_direction_input(button->gpio);
453 "Failed to configure direction for GPIO %d, error %d\n",
454 button->gpio, error);
458 if (button->debounce_interval) {
459 error = gpio_set_debounce(button->gpio,
460 button->debounce_interval * 1000);
461 /* use timer if gpiolib doesn't provide debounce */
463 bdata->timer_debounce =
464 button->debounce_interval;
467 irq = gpio_to_irq(button->gpio);
471 "Unable to get irq number for GPIO %d, error %d\n",
472 button->gpio, error);
477 INIT_WORK(&bdata->work, gpio_keys_gpio_work_func);
478 setup_timer(&bdata->timer,
479 gpio_keys_gpio_timer, (unsigned long)bdata);
481 isr = gpio_keys_gpio_isr;
482 irqflags = IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING;
486 dev_err(dev, "No IRQ specified\n");
489 bdata->irq = button->irq;
491 if (button->type && button->type != EV_KEY) {
492 dev_err(dev, "Only EV_KEY allowed for IRQ buttons.\n");
496 bdata->timer_debounce = button->debounce_interval;
497 setup_timer(&bdata->timer,
498 gpio_keys_irq_timer, (unsigned long)bdata);
500 isr = gpio_keys_irq_isr;
504 input_set_capability(input, button->type ?: EV_KEY, button->code);
507 * If platform has specified that the button can be disabled,
508 * we don't want it to share the interrupt line.
510 if (!button->can_disable)
511 irqflags |= IRQF_SHARED;
513 error = request_any_context_irq(bdata->irq, isr, irqflags, desc, bdata);
515 dev_err(dev, "Unable to claim irq %d; error %d\n",
523 if (gpio_is_valid(button->gpio))
524 gpio_free(button->gpio);
529 static int gpio_keys_open(struct input_dev *input)
531 struct gpio_keys_drvdata *ddata = input_get_drvdata(input);
532 const struct gpio_keys_platform_data *pdata = ddata->pdata;
534 return pdata->enable ? pdata->enable(input->dev.parent) : 0;
537 static void gpio_keys_close(struct input_dev *input)
539 struct gpio_keys_drvdata *ddata = input_get_drvdata(input);
540 const struct gpio_keys_platform_data *pdata = ddata->pdata;
543 pdata->disable(input->dev.parent);
547 * Handlers for alternative sources of platform_data
552 * Translate OpenFirmware node properties into platform_data
554 static struct gpio_keys_platform_data * __devinit
555 gpio_keys_get_devtree_pdata(struct device *dev)
557 struct device_node *node, *pp;
558 struct gpio_keys_platform_data *pdata;
559 struct gpio_keys_button *button;
570 nbuttons = of_get_child_count(node);
576 pdata = kzalloc(sizeof(*pdata) + nbuttons * (sizeof *button),
583 pdata->buttons = (struct gpio_keys_button *)(pdata + 1);
584 pdata->nbuttons = nbuttons;
586 pdata->rep = !!of_get_property(node, "autorepeat", NULL);
589 for_each_child_of_node(node, pp) {
590 enum of_gpio_flags flags;
592 if (!of_find_property(pp, "gpios", NULL)) {
594 dev_warn(dev, "Found button without gpios\n");
598 button = &pdata->buttons[i++];
600 button->gpio = of_get_gpio_flags(pp, 0, &flags);
601 button->active_low = flags & OF_GPIO_ACTIVE_LOW;
603 if (of_property_read_u32(pp, "linux,code", &button->code)) {
604 dev_err(dev, "Button without keycode: 0x%x\n",
610 button->desc = of_get_property(pp, "label", NULL);
612 if (of_property_read_u32(pp, "linux,input-type", &button->type))
613 button->type = EV_KEY;
615 button->wakeup = !!of_get_property(pp, "gpio-key,wakeup", NULL);
617 if (of_property_read_u32(pp, "debounce-interval",
618 &button->debounce_interval))
619 button->debounce_interval = 5;
622 if (pdata->nbuttons == 0) {
632 return ERR_PTR(error);
635 static struct of_device_id gpio_keys_of_match[] = {
636 { .compatible = "gpio-keys", },
639 MODULE_DEVICE_TABLE(of, gpio_keys_of_match);
643 static inline struct gpio_keys_platform_data *
644 gpio_keys_get_devtree_pdata(struct device *dev)
646 return ERR_PTR(-ENODEV);
651 static void gpio_remove_key(struct gpio_button_data *bdata)
653 free_irq(bdata->irq, bdata);
654 if (bdata->timer_debounce)
655 del_timer_sync(&bdata->timer);
656 cancel_work_sync(&bdata->work);
657 if (gpio_is_valid(bdata->button->gpio))
658 gpio_free(bdata->button->gpio);
661 static int __devinit gpio_keys_probe(struct platform_device *pdev)
663 struct device *dev = &pdev->dev;
664 const struct gpio_keys_platform_data *pdata = dev_get_platdata(dev);
665 struct gpio_keys_drvdata *ddata;
666 struct input_dev *input;
671 pdata = gpio_keys_get_devtree_pdata(dev);
673 return PTR_ERR(pdata);
676 ddata = kzalloc(sizeof(struct gpio_keys_drvdata) +
677 pdata->nbuttons * sizeof(struct gpio_button_data),
679 input = input_allocate_device();
680 if (!ddata || !input) {
681 dev_err(dev, "failed to allocate state\n");
686 ddata->pdata = pdata;
687 ddata->input = input;
688 mutex_init(&ddata->disable_lock);
690 platform_set_drvdata(pdev, ddata);
691 input_set_drvdata(input, ddata);
693 input->name = pdata->name ? : pdev->name;
694 input->phys = "gpio-keys/input0";
695 input->dev.parent = &pdev->dev;
696 input->open = gpio_keys_open;
697 input->close = gpio_keys_close;
699 input->id.bustype = BUS_HOST;
700 input->id.vendor = 0x0001;
701 input->id.product = 0x0001;
702 input->id.version = 0x0100;
704 /* Enable auto repeat feature of Linux input subsystem */
706 __set_bit(EV_REP, input->evbit);
708 for (i = 0; i < pdata->nbuttons; i++) {
709 const struct gpio_keys_button *button = &pdata->buttons[i];
710 struct gpio_button_data *bdata = &ddata->data[i];
712 error = gpio_keys_setup_key(pdev, input, bdata, button);
720 error = sysfs_create_group(&pdev->dev.kobj, &gpio_keys_attr_group);
722 dev_err(dev, "Unable to export keys/switches, error: %d\n",
727 error = input_register_device(input);
729 dev_err(dev, "Unable to register input device, error: %d\n",
734 /* get current state of buttons that are connected to GPIOs */
735 for (i = 0; i < pdata->nbuttons; i++) {
736 struct gpio_button_data *bdata = &ddata->data[i];
737 if (gpio_is_valid(bdata->button->gpio))
738 gpio_keys_gpio_report_event(bdata);
742 device_init_wakeup(&pdev->dev, wakeup);
747 sysfs_remove_group(&pdev->dev.kobj, &gpio_keys_attr_group);
750 gpio_remove_key(&ddata->data[i]);
752 platform_set_drvdata(pdev, NULL);
754 input_free_device(input);
756 /* If we have no platform data, we allocated pdata dynamically. */
757 if (!dev_get_platdata(&pdev->dev))
763 static int __devexit gpio_keys_remove(struct platform_device *pdev)
765 struct gpio_keys_drvdata *ddata = platform_get_drvdata(pdev);
766 struct input_dev *input = ddata->input;
769 sysfs_remove_group(&pdev->dev.kobj, &gpio_keys_attr_group);
771 device_init_wakeup(&pdev->dev, 0);
773 for (i = 0; i < ddata->pdata->nbuttons; i++)
774 gpio_remove_key(&ddata->data[i]);
776 input_unregister_device(input);
778 /* If we have no platform data, we allocated pdata dynamically. */
779 if (!dev_get_platdata(&pdev->dev))
787 #ifdef CONFIG_PM_SLEEP
788 static int gpio_keys_suspend(struct device *dev)
790 struct gpio_keys_drvdata *ddata = dev_get_drvdata(dev);
793 if (device_may_wakeup(dev)) {
794 for (i = 0; i < ddata->pdata->nbuttons; i++) {
795 struct gpio_button_data *bdata = &ddata->data[i];
796 if (bdata->button->wakeup)
797 enable_irq_wake(bdata->irq);
804 static int gpio_keys_resume(struct device *dev)
806 struct gpio_keys_drvdata *ddata = dev_get_drvdata(dev);
809 for (i = 0; i < ddata->pdata->nbuttons; i++) {
810 struct gpio_button_data *bdata = &ddata->data[i];
811 if (bdata->button->wakeup && device_may_wakeup(dev))
812 disable_irq_wake(bdata->irq);
814 if (gpio_is_valid(bdata->button->gpio))
815 gpio_keys_gpio_report_event(bdata);
817 input_sync(ddata->input);
823 static SIMPLE_DEV_PM_OPS(gpio_keys_pm_ops, gpio_keys_suspend, gpio_keys_resume);
825 static struct platform_driver gpio_keys_device_driver = {
826 .probe = gpio_keys_probe,
827 .remove = gpio_keys_remove,
830 .owner = THIS_MODULE,
831 .pm = &gpio_keys_pm_ops,
832 .of_match_table = of_match_ptr(gpio_keys_of_match),
836 static int __init gpio_keys_init(void)
838 return platform_driver_register(&gpio_keys_device_driver);
841 static void __exit gpio_keys_exit(void)
843 platform_driver_unregister(&gpio_keys_device_driver);
846 late_initcall(gpio_keys_init);
847 module_exit(gpio_keys_exit);
849 MODULE_LICENSE("GPL");
850 MODULE_AUTHOR("Phil Blundell <pb@handhelds.org>");
851 MODULE_DESCRIPTION("Keyboard driver for GPIOs");
852 MODULE_ALIAS("platform:gpio-keys");