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>
30 #include <linux/of_platform.h>
31 #include <linux/of_gpio.h>
32 #include <linux/spinlock.h>
34 struct gpio_button_data {
35 const struct gpio_keys_button *button;
36 struct input_dev *input;
37 struct timer_list timer;
38 struct work_struct work;
39 unsigned int timer_debounce; /* in msecs */
46 struct gpio_keys_drvdata {
47 const struct gpio_keys_platform_data *pdata;
48 struct input_dev *input;
49 struct mutex disable_lock;
50 struct gpio_button_data data[0];
54 * SYSFS interface for enabling/disabling keys and switches:
56 * There are 4 attributes under /sys/devices/platform/gpio-keys/
57 * keys [ro] - bitmap of keys (EV_KEY) which can be
59 * switches [ro] - bitmap of switches (EV_SW) which can be
61 * disabled_keys [rw] - bitmap of keys currently disabled
62 * disabled_switches [rw] - bitmap of switches currently disabled
64 * Userland can change these values and hence disable event generation
65 * for each key (or switch). Disabling a key means its interrupt line
68 * For example, if we have following switches set up as gpio-keys:
70 * SW_CAMERA_LENS_COVER = 9
71 * SW_KEYPAD_SLIDE = 10
72 * SW_FRONT_PROXIMITY = 11
73 * This is read from switches:
75 * Next we want to disable proximity (11) and dock (5), we write:
77 * to file disabled_switches. Now proximity and dock IRQs are disabled.
78 * This can be verified by reading the file disabled_switches:
80 * If we now want to enable proximity (11) switch we write:
82 * to disabled_switches.
84 * We can disable only those keys which don't allow sharing the irq.
88 * get_n_events_by_type() - returns maximum number of events per @type
89 * @type: type of button (%EV_KEY, %EV_SW)
91 * Return value of this function can be used to allocate bitmap
92 * large enough to hold all bits for given type.
94 static inline int get_n_events_by_type(int type)
96 BUG_ON(type != EV_SW && type != EV_KEY);
98 return (type == EV_KEY) ? KEY_CNT : SW_CNT;
102 * gpio_keys_disable_button() - disables given GPIO button
103 * @bdata: button data for button to be disabled
105 * Disables button pointed by @bdata. This is done by masking
106 * IRQ line. After this function is called, button won't generate
107 * input events anymore. Note that one can only disable buttons
108 * that don't share IRQs.
110 * Make sure that @bdata->disable_lock is locked when entering
111 * this function to avoid races when concurrent threads are
112 * disabling buttons at the same time.
114 static void gpio_keys_disable_button(struct gpio_button_data *bdata)
116 if (!bdata->disabled) {
118 * Disable IRQ and possible debouncing timer.
120 disable_irq(bdata->irq);
121 if (bdata->timer_debounce)
122 del_timer_sync(&bdata->timer);
124 bdata->disabled = true;
129 * gpio_keys_enable_button() - enables given GPIO button
130 * @bdata: button data for button to be disabled
132 * Enables given button pointed by @bdata.
134 * Make sure that @bdata->disable_lock is locked when entering
135 * this function to avoid races with concurrent threads trying
136 * to enable the same button at the same time.
138 static void gpio_keys_enable_button(struct gpio_button_data *bdata)
140 if (bdata->disabled) {
141 enable_irq(bdata->irq);
142 bdata->disabled = false;
147 * gpio_keys_attr_show_helper() - fill in stringified bitmap of buttons
148 * @ddata: pointer to drvdata
149 * @buf: buffer where stringified bitmap is written
150 * @type: button type (%EV_KEY, %EV_SW)
151 * @only_disabled: does caller want only those buttons that are
152 * currently disabled or all buttons that can be
155 * This function writes buttons that can be disabled to @buf. If
156 * @only_disabled is true, then @buf contains only those buttons
157 * that are currently disabled. Returns 0 on success or negative
160 static ssize_t gpio_keys_attr_show_helper(struct gpio_keys_drvdata *ddata,
161 char *buf, unsigned int type,
164 int n_events = get_n_events_by_type(type);
169 bits = kcalloc(BITS_TO_LONGS(n_events), sizeof(*bits), GFP_KERNEL);
173 for (i = 0; i < ddata->pdata->nbuttons; i++) {
174 struct gpio_button_data *bdata = &ddata->data[i];
176 if (bdata->button->type != type)
179 if (only_disabled && !bdata->disabled)
182 __set_bit(bdata->button->code, bits);
185 ret = bitmap_scnlistprintf(buf, PAGE_SIZE - 2, bits, n_events);
195 * gpio_keys_attr_store_helper() - enable/disable buttons based on given bitmap
196 * @ddata: pointer to drvdata
197 * @buf: buffer from userspace that contains stringified bitmap
198 * @type: button type (%EV_KEY, %EV_SW)
200 * This function parses stringified bitmap from @buf and disables/enables
201 * GPIO buttons accordingly. Returns 0 on success and negative error
204 static ssize_t gpio_keys_attr_store_helper(struct gpio_keys_drvdata *ddata,
205 const char *buf, unsigned int type)
207 int n_events = get_n_events_by_type(type);
212 bits = kcalloc(BITS_TO_LONGS(n_events), sizeof(*bits), GFP_KERNEL);
216 error = bitmap_parselist(buf, bits, n_events);
221 for (i = 0; i < ddata->pdata->nbuttons; i++) {
222 struct gpio_button_data *bdata = &ddata->data[i];
224 if (bdata->button->type != type)
227 if (test_bit(bdata->button->code, bits) &&
228 !bdata->button->can_disable) {
234 mutex_lock(&ddata->disable_lock);
236 for (i = 0; i < ddata->pdata->nbuttons; i++) {
237 struct gpio_button_data *bdata = &ddata->data[i];
239 if (bdata->button->type != type)
242 if (test_bit(bdata->button->code, bits))
243 gpio_keys_disable_button(bdata);
245 gpio_keys_enable_button(bdata);
248 mutex_unlock(&ddata->disable_lock);
255 #define ATTR_SHOW_FN(name, type, only_disabled) \
256 static ssize_t gpio_keys_show_##name(struct device *dev, \
257 struct device_attribute *attr, \
260 struct platform_device *pdev = to_platform_device(dev); \
261 struct gpio_keys_drvdata *ddata = platform_get_drvdata(pdev); \
263 return gpio_keys_attr_show_helper(ddata, buf, \
264 type, only_disabled); \
267 ATTR_SHOW_FN(keys, EV_KEY, false);
268 ATTR_SHOW_FN(switches, EV_SW, false);
269 ATTR_SHOW_FN(disabled_keys, EV_KEY, true);
270 ATTR_SHOW_FN(disabled_switches, EV_SW, true);
275 * /sys/devices/platform/gpio-keys/keys [ro]
276 * /sys/devices/platform/gpio-keys/switches [ro]
278 static DEVICE_ATTR(keys, S_IRUGO, gpio_keys_show_keys, NULL);
279 static DEVICE_ATTR(switches, S_IRUGO, gpio_keys_show_switches, NULL);
281 #define ATTR_STORE_FN(name, type) \
282 static ssize_t gpio_keys_store_##name(struct device *dev, \
283 struct device_attribute *attr, \
287 struct platform_device *pdev = to_platform_device(dev); \
288 struct gpio_keys_drvdata *ddata = platform_get_drvdata(pdev); \
291 error = gpio_keys_attr_store_helper(ddata, buf, type); \
298 ATTR_STORE_FN(disabled_keys, EV_KEY);
299 ATTR_STORE_FN(disabled_switches, EV_SW);
304 * /sys/devices/platform/gpio-keys/disabled_keys [rw]
305 * /sys/devices/platform/gpio-keys/disables_switches [rw]
307 static DEVICE_ATTR(disabled_keys, S_IWUSR | S_IRUGO,
308 gpio_keys_show_disabled_keys,
309 gpio_keys_store_disabled_keys);
310 static DEVICE_ATTR(disabled_switches, S_IWUSR | S_IRUGO,
311 gpio_keys_show_disabled_switches,
312 gpio_keys_store_disabled_switches);
314 static struct attribute *gpio_keys_attrs[] = {
316 &dev_attr_switches.attr,
317 &dev_attr_disabled_keys.attr,
318 &dev_attr_disabled_switches.attr,
322 static struct attribute_group gpio_keys_attr_group = {
323 .attrs = gpio_keys_attrs,
326 static void gpio_keys_gpio_report_event(struct gpio_button_data *bdata)
328 const struct gpio_keys_button *button = bdata->button;
329 struct input_dev *input = bdata->input;
330 unsigned int type = button->type ?: EV_KEY;
331 int state = (gpio_get_value_cansleep(button->gpio) ? 1 : 0) ^ button->active_low;
333 if (type == EV_ABS) {
335 input_event(input, type, button->code, button->value);
337 input_event(input, type, button->code, !!state);
342 static void gpio_keys_gpio_work_func(struct work_struct *work)
344 struct gpio_button_data *bdata =
345 container_of(work, struct gpio_button_data, work);
347 gpio_keys_gpio_report_event(bdata);
349 if (bdata->button->wakeup)
350 pm_relax(bdata->input->dev.parent);
353 static void gpio_keys_gpio_timer(unsigned long _data)
355 struct gpio_button_data *bdata = (struct gpio_button_data *)_data;
357 schedule_work(&bdata->work);
360 static irqreturn_t gpio_keys_gpio_isr(int irq, void *dev_id)
362 struct gpio_button_data *bdata = dev_id;
364 BUG_ON(irq != bdata->irq);
366 if (bdata->button->wakeup)
367 pm_stay_awake(bdata->input->dev.parent);
368 if (bdata->timer_debounce)
369 mod_timer(&bdata->timer,
370 jiffies + msecs_to_jiffies(bdata->timer_debounce));
372 schedule_work(&bdata->work);
377 static void gpio_keys_irq_timer(unsigned long _data)
379 struct gpio_button_data *bdata = (struct gpio_button_data *)_data;
380 struct input_dev *input = bdata->input;
383 spin_lock_irqsave(&bdata->lock, flags);
384 if (bdata->key_pressed) {
385 input_event(input, EV_KEY, bdata->button->code, 0);
387 bdata->key_pressed = false;
389 spin_unlock_irqrestore(&bdata->lock, flags);
392 static irqreturn_t gpio_keys_irq_isr(int irq, void *dev_id)
394 struct gpio_button_data *bdata = dev_id;
395 const struct gpio_keys_button *button = bdata->button;
396 struct input_dev *input = bdata->input;
399 BUG_ON(irq != bdata->irq);
401 spin_lock_irqsave(&bdata->lock, flags);
403 if (!bdata->key_pressed) {
404 if (bdata->button->wakeup)
405 pm_wakeup_event(bdata->input->dev.parent, 0);
407 input_event(input, EV_KEY, button->code, 1);
410 if (!bdata->timer_debounce) {
411 input_event(input, EV_KEY, button->code, 0);
416 bdata->key_pressed = true;
419 if (bdata->timer_debounce)
420 mod_timer(&bdata->timer,
421 jiffies + msecs_to_jiffies(bdata->timer_debounce));
423 spin_unlock_irqrestore(&bdata->lock, flags);
427 static void gpio_keys_quiesce_key(void *data)
429 struct gpio_button_data *bdata = data;
431 if (bdata->timer_debounce)
432 del_timer_sync(&bdata->timer);
434 cancel_work_sync(&bdata->work);
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)
442 const char *desc = button->desc ? button->desc : "gpio_keys";
443 struct device *dev = &pdev->dev;
445 unsigned long irqflags;
449 bdata->input = input;
450 bdata->button = button;
451 spin_lock_init(&bdata->lock);
453 if (gpio_is_valid(button->gpio)) {
455 error = devm_gpio_request_one(&pdev->dev, button->gpio,
458 dev_err(dev, "Failed to request GPIO %d, error %d\n",
459 button->gpio, error);
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 */
468 bdata->timer_debounce =
469 button->debounce_interval;
472 irq = gpio_to_irq(button->gpio);
476 "Unable to get irq number for GPIO %d, error %d\n",
477 button->gpio, error);
482 INIT_WORK(&bdata->work, gpio_keys_gpio_work_func);
483 setup_timer(&bdata->timer,
484 gpio_keys_gpio_timer, (unsigned long)bdata);
486 isr = gpio_keys_gpio_isr;
487 irqflags = IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING;
491 dev_err(dev, "No IRQ specified\n");
494 bdata->irq = button->irq;
496 if (button->type && button->type != EV_KEY) {
497 dev_err(dev, "Only EV_KEY allowed for IRQ buttons.\n");
501 bdata->timer_debounce = button->debounce_interval;
502 setup_timer(&bdata->timer,
503 gpio_keys_irq_timer, (unsigned long)bdata);
505 isr = gpio_keys_irq_isr;
509 input_set_capability(input, button->type ?: EV_KEY, button->code);
512 * Install custom action to cancel debounce timer and
515 error = devm_add_action(&pdev->dev, gpio_keys_quiesce_key, bdata);
518 "failed to register quiesce action, error: %d\n",
524 * If platform has specified that the button can be disabled,
525 * we don't want it to share the interrupt line.
527 if (!button->can_disable)
528 irqflags |= IRQF_SHARED;
530 error = devm_request_any_context_irq(&pdev->dev, bdata->irq,
531 isr, irqflags, desc, bdata);
533 dev_err(dev, "Unable to claim irq %d; error %d\n",
541 static void gpio_keys_report_state(struct gpio_keys_drvdata *ddata)
543 struct input_dev *input = ddata->input;
546 for (i = 0; i < ddata->pdata->nbuttons; i++) {
547 struct gpio_button_data *bdata = &ddata->data[i];
548 if (gpio_is_valid(bdata->button->gpio))
549 gpio_keys_gpio_report_event(bdata);
554 static int gpio_keys_open(struct input_dev *input)
556 struct gpio_keys_drvdata *ddata = input_get_drvdata(input);
557 const struct gpio_keys_platform_data *pdata = ddata->pdata;
561 error = pdata->enable(input->dev.parent);
566 /* Report current state of buttons that are connected to GPIOs */
567 gpio_keys_report_state(ddata);
572 static void gpio_keys_close(struct input_dev *input)
574 struct gpio_keys_drvdata *ddata = input_get_drvdata(input);
575 const struct gpio_keys_platform_data *pdata = ddata->pdata;
578 pdata->disable(input->dev.parent);
582 * Handlers for alternative sources of platform_data
587 * Translate OpenFirmware node properties into platform_data
589 static struct gpio_keys_platform_data *
590 gpio_keys_get_devtree_pdata(struct device *dev)
592 struct device_node *node, *pp;
593 struct gpio_keys_platform_data *pdata;
594 struct gpio_keys_button *button;
601 return ERR_PTR(-ENODEV);
603 nbuttons = of_get_child_count(node);
605 return ERR_PTR(-ENODEV);
607 pdata = devm_kzalloc(dev,
608 sizeof(*pdata) + nbuttons * sizeof(*button),
611 return ERR_PTR(-ENOMEM);
613 pdata->buttons = (struct gpio_keys_button *)(pdata + 1);
614 pdata->nbuttons = nbuttons;
616 pdata->rep = !!of_get_property(node, "autorepeat", NULL);
619 for_each_child_of_node(node, pp) {
621 enum of_gpio_flags flags;
623 if (!of_find_property(pp, "gpios", NULL)) {
625 dev_warn(dev, "Found button without gpios\n");
629 gpio = of_get_gpio_flags(pp, 0, &flags);
632 if (error != -EPROBE_DEFER)
634 "Failed to get gpio flags, error: %d\n",
636 return ERR_PTR(error);
639 button = &pdata->buttons[i++];
642 button->active_low = flags & OF_GPIO_ACTIVE_LOW;
644 if (of_property_read_u32(pp, "linux,code", &button->code)) {
645 dev_err(dev, "Button without keycode: 0x%x\n",
647 return ERR_PTR(-EINVAL);
650 button->desc = of_get_property(pp, "label", NULL);
652 if (of_property_read_u32(pp, "linux,input-type", &button->type))
653 button->type = EV_KEY;
655 button->wakeup = !!of_get_property(pp, "gpio-key,wakeup", NULL);
657 if (of_property_read_u32(pp, "debounce-interval",
658 &button->debounce_interval))
659 button->debounce_interval = 5;
662 if (pdata->nbuttons == 0)
663 return ERR_PTR(-EINVAL);
668 static const struct of_device_id gpio_keys_of_match[] = {
669 { .compatible = "gpio-keys", },
672 MODULE_DEVICE_TABLE(of, gpio_keys_of_match);
676 static inline struct gpio_keys_platform_data *
677 gpio_keys_get_devtree_pdata(struct device *dev)
679 return ERR_PTR(-ENODEV);
684 static int gpio_keys_probe(struct platform_device *pdev)
686 struct device *dev = &pdev->dev;
687 const struct gpio_keys_platform_data *pdata = dev_get_platdata(dev);
688 struct gpio_keys_drvdata *ddata;
689 struct input_dev *input;
695 pdata = gpio_keys_get_devtree_pdata(dev);
697 return PTR_ERR(pdata);
700 size = sizeof(struct gpio_keys_drvdata) +
701 pdata->nbuttons * sizeof(struct gpio_button_data);
702 ddata = devm_kzalloc(dev, size, GFP_KERNEL);
704 dev_err(dev, "failed to allocate state\n");
708 input = devm_input_allocate_device(dev);
710 dev_err(dev, "failed to allocate input device\n");
714 ddata->pdata = pdata;
715 ddata->input = input;
716 mutex_init(&ddata->disable_lock);
718 platform_set_drvdata(pdev, ddata);
719 input_set_drvdata(input, ddata);
721 input->name = pdata->name ? : pdev->name;
722 input->phys = "gpio-keys/input0";
723 input->dev.parent = &pdev->dev;
724 input->open = gpio_keys_open;
725 input->close = gpio_keys_close;
727 input->id.bustype = BUS_HOST;
728 input->id.vendor = 0x0001;
729 input->id.product = 0x0001;
730 input->id.version = 0x0100;
732 /* Enable auto repeat feature of Linux input subsystem */
734 __set_bit(EV_REP, input->evbit);
736 for (i = 0; i < pdata->nbuttons; i++) {
737 const struct gpio_keys_button *button = &pdata->buttons[i];
738 struct gpio_button_data *bdata = &ddata->data[i];
740 error = gpio_keys_setup_key(pdev, input, bdata, button);
748 error = sysfs_create_group(&pdev->dev.kobj, &gpio_keys_attr_group);
750 dev_err(dev, "Unable to export keys/switches, error: %d\n",
755 error = input_register_device(input);
757 dev_err(dev, "Unable to register input device, error: %d\n",
759 goto err_remove_group;
762 device_init_wakeup(&pdev->dev, wakeup);
767 sysfs_remove_group(&pdev->dev.kobj, &gpio_keys_attr_group);
771 static int gpio_keys_remove(struct platform_device *pdev)
773 sysfs_remove_group(&pdev->dev.kobj, &gpio_keys_attr_group);
775 device_init_wakeup(&pdev->dev, 0);
780 #ifdef CONFIG_PM_SLEEP
781 static int gpio_keys_suspend(struct device *dev)
783 struct gpio_keys_drvdata *ddata = dev_get_drvdata(dev);
784 struct input_dev *input = ddata->input;
787 if (device_may_wakeup(dev)) {
788 for (i = 0; i < ddata->pdata->nbuttons; i++) {
789 struct gpio_button_data *bdata = &ddata->data[i];
790 if (bdata->button->wakeup)
791 enable_irq_wake(bdata->irq);
794 mutex_lock(&input->mutex);
796 gpio_keys_close(input);
797 mutex_unlock(&input->mutex);
803 static int gpio_keys_resume(struct device *dev)
805 struct gpio_keys_drvdata *ddata = dev_get_drvdata(dev);
806 struct input_dev *input = ddata->input;
810 if (device_may_wakeup(dev)) {
811 for (i = 0; i < ddata->pdata->nbuttons; i++) {
812 struct gpio_button_data *bdata = &ddata->data[i];
813 if (bdata->button->wakeup)
814 disable_irq_wake(bdata->irq);
817 mutex_lock(&input->mutex);
819 error = gpio_keys_open(input);
820 mutex_unlock(&input->mutex);
826 gpio_keys_report_state(ddata);
831 static SIMPLE_DEV_PM_OPS(gpio_keys_pm_ops, gpio_keys_suspend, gpio_keys_resume);
833 static struct platform_driver gpio_keys_device_driver = {
834 .probe = gpio_keys_probe,
835 .remove = gpio_keys_remove,
838 .owner = THIS_MODULE,
839 .pm = &gpio_keys_pm_ops,
840 .of_match_table = of_match_ptr(gpio_keys_of_match),
844 static int __init gpio_keys_init(void)
846 return platform_driver_register(&gpio_keys_device_driver);
849 static void __exit gpio_keys_exit(void)
851 platform_driver_unregister(&gpio_keys_device_driver);
854 late_initcall(gpio_keys_init);
855 module_exit(gpio_keys_exit);
857 MODULE_LICENSE("GPL");
858 MODULE_AUTHOR("Phil Blundell <pb@handhelds.org>");
859 MODULE_DESCRIPTION("Keyboard driver for GPIOs");
860 MODULE_ALIAS("platform:gpio-keys");