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 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_one(button
->gpio
, GPIOF_IN
, desc
);
445 dev_err(dev
, "Failed to request GPIO %d, error %d\n",
446 button
->gpio
, error
);
450 if (button
->debounce_interval
) {
451 error
= gpio_set_debounce(button
->gpio
,
452 button
->debounce_interval
* 1000);
453 /* use timer if gpiolib doesn't provide debounce */
455 bdata
->timer_debounce
=
456 button
->debounce_interval
;
459 irq
= gpio_to_irq(button
->gpio
);
463 "Unable to get irq number for GPIO %d, error %d\n",
464 button
->gpio
, error
);
469 INIT_WORK(&bdata
->work
, gpio_keys_gpio_work_func
);
470 setup_timer(&bdata
->timer
,
471 gpio_keys_gpio_timer
, (unsigned long)bdata
);
473 isr
= gpio_keys_gpio_isr
;
474 irqflags
= IRQF_TRIGGER_RISING
| IRQF_TRIGGER_FALLING
;
478 dev_err(dev
, "No IRQ specified\n");
481 bdata
->irq
= button
->irq
;
483 if (button
->type
&& button
->type
!= EV_KEY
) {
484 dev_err(dev
, "Only EV_KEY allowed for IRQ buttons.\n");
488 bdata
->timer_debounce
= button
->debounce_interval
;
489 setup_timer(&bdata
->timer
,
490 gpio_keys_irq_timer
, (unsigned long)bdata
);
492 isr
= gpio_keys_irq_isr
;
496 input_set_capability(input
, button
->type
?: EV_KEY
, button
->code
);
499 * If platform has specified that the button can be disabled,
500 * we don't want it to share the interrupt line.
502 if (!button
->can_disable
)
503 irqflags
|= IRQF_SHARED
;
505 error
= request_any_context_irq(bdata
->irq
, isr
, irqflags
, desc
, bdata
);
507 dev_err(dev
, "Unable to claim irq %d; error %d\n",
515 if (gpio_is_valid(button
->gpio
))
516 gpio_free(button
->gpio
);
521 static void gpio_keys_report_state(struct gpio_keys_drvdata
*ddata
)
523 struct input_dev
*input
= ddata
->input
;
526 for (i
= 0; i
< ddata
->pdata
->nbuttons
; i
++) {
527 struct gpio_button_data
*bdata
= &ddata
->data
[i
];
528 if (gpio_is_valid(bdata
->button
->gpio
))
529 gpio_keys_gpio_report_event(bdata
);
534 static int gpio_keys_open(struct input_dev
*input
)
536 struct gpio_keys_drvdata
*ddata
= input_get_drvdata(input
);
537 const struct gpio_keys_platform_data
*pdata
= ddata
->pdata
;
541 error
= pdata
->enable(input
->dev
.parent
);
546 /* Report current state of buttons that are connected to GPIOs */
547 gpio_keys_report_state(ddata
);
552 static void gpio_keys_close(struct input_dev
*input
)
554 struct gpio_keys_drvdata
*ddata
= input_get_drvdata(input
);
555 const struct gpio_keys_platform_data
*pdata
= ddata
->pdata
;
558 pdata
->disable(input
->dev
.parent
);
562 * Handlers for alternative sources of platform_data
567 * Translate OpenFirmware node properties into platform_data
569 static struct gpio_keys_platform_data
*
570 gpio_keys_get_devtree_pdata(struct device
*dev
)
572 struct device_node
*node
, *pp
;
573 struct gpio_keys_platform_data
*pdata
;
574 struct gpio_keys_button
*button
;
585 nbuttons
= of_get_child_count(node
);
591 pdata
= kzalloc(sizeof(*pdata
) + nbuttons
* (sizeof *button
),
598 pdata
->buttons
= (struct gpio_keys_button
*)(pdata
+ 1);
599 pdata
->nbuttons
= nbuttons
;
601 pdata
->rep
= !!of_get_property(node
, "autorepeat", NULL
);
604 for_each_child_of_node(node
, pp
) {
606 enum of_gpio_flags flags
;
608 if (!of_find_property(pp
, "gpios", NULL
)) {
610 dev_warn(dev
, "Found button without gpios\n");
614 gpio
= of_get_gpio_flags(pp
, 0, &flags
);
617 if (error
!= -EPROBE_DEFER
)
619 "Failed to get gpio flags, error: %d\n",
624 button
= &pdata
->buttons
[i
++];
627 button
->active_low
= flags
& OF_GPIO_ACTIVE_LOW
;
629 if (of_property_read_u32(pp
, "linux,code", &button
->code
)) {
630 dev_err(dev
, "Button without keycode: 0x%x\n",
636 button
->desc
= of_get_property(pp
, "label", NULL
);
638 if (of_property_read_u32(pp
, "linux,input-type", &button
->type
))
639 button
->type
= EV_KEY
;
641 button
->wakeup
= !!of_get_property(pp
, "gpio-key,wakeup", NULL
);
643 if (of_property_read_u32(pp
, "debounce-interval",
644 &button
->debounce_interval
))
645 button
->debounce_interval
= 5;
648 if (pdata
->nbuttons
== 0) {
658 return ERR_PTR(error
);
661 static struct of_device_id gpio_keys_of_match
[] = {
662 { .compatible
= "gpio-keys", },
665 MODULE_DEVICE_TABLE(of
, gpio_keys_of_match
);
669 static inline struct gpio_keys_platform_data
*
670 gpio_keys_get_devtree_pdata(struct device
*dev
)
672 return ERR_PTR(-ENODEV
);
677 static void gpio_remove_key(struct gpio_button_data
*bdata
)
679 free_irq(bdata
->irq
, bdata
);
680 if (bdata
->timer_debounce
)
681 del_timer_sync(&bdata
->timer
);
682 cancel_work_sync(&bdata
->work
);
683 if (gpio_is_valid(bdata
->button
->gpio
))
684 gpio_free(bdata
->button
->gpio
);
687 static int gpio_keys_probe(struct platform_device
*pdev
)
689 struct device
*dev
= &pdev
->dev
;
690 const struct gpio_keys_platform_data
*pdata
= dev_get_platdata(dev
);
691 struct gpio_keys_drvdata
*ddata
;
692 struct input_dev
*input
;
697 pdata
= gpio_keys_get_devtree_pdata(dev
);
699 return PTR_ERR(pdata
);
702 ddata
= kzalloc(sizeof(struct gpio_keys_drvdata
) +
703 pdata
->nbuttons
* sizeof(struct gpio_button_data
),
705 input
= input_allocate_device();
706 if (!ddata
|| !input
) {
707 dev_err(dev
, "failed to allocate state\n");
712 ddata
->pdata
= pdata
;
713 ddata
->input
= input
;
714 mutex_init(&ddata
->disable_lock
);
716 platform_set_drvdata(pdev
, ddata
);
717 input_set_drvdata(input
, ddata
);
719 input
->name
= pdata
->name
? : pdev
->name
;
720 input
->phys
= "gpio-keys/input0";
721 input
->dev
.parent
= &pdev
->dev
;
722 input
->open
= gpio_keys_open
;
723 input
->close
= gpio_keys_close
;
725 input
->id
.bustype
= BUS_HOST
;
726 input
->id
.vendor
= 0x0001;
727 input
->id
.product
= 0x0001;
728 input
->id
.version
= 0x0100;
730 /* Enable auto repeat feature of Linux input subsystem */
732 __set_bit(EV_REP
, input
->evbit
);
734 for (i
= 0; i
< pdata
->nbuttons
; i
++) {
735 const struct gpio_keys_button
*button
= &pdata
->buttons
[i
];
736 struct gpio_button_data
*bdata
= &ddata
->data
[i
];
738 error
= gpio_keys_setup_key(pdev
, input
, bdata
, button
);
746 error
= sysfs_create_group(&pdev
->dev
.kobj
, &gpio_keys_attr_group
);
748 dev_err(dev
, "Unable to export keys/switches, error: %d\n",
753 error
= input_register_device(input
);
755 dev_err(dev
, "Unable to register input device, error: %d\n",
760 device_init_wakeup(&pdev
->dev
, wakeup
);
765 sysfs_remove_group(&pdev
->dev
.kobj
, &gpio_keys_attr_group
);
768 gpio_remove_key(&ddata
->data
[i
]);
770 platform_set_drvdata(pdev
, NULL
);
772 input_free_device(input
);
774 /* If we have no platform data, we allocated pdata dynamically. */
775 if (!dev_get_platdata(&pdev
->dev
))
781 static int gpio_keys_remove(struct platform_device
*pdev
)
783 struct gpio_keys_drvdata
*ddata
= platform_get_drvdata(pdev
);
784 struct input_dev
*input
= ddata
->input
;
787 sysfs_remove_group(&pdev
->dev
.kobj
, &gpio_keys_attr_group
);
789 device_init_wakeup(&pdev
->dev
, 0);
791 for (i
= 0; i
< ddata
->pdata
->nbuttons
; i
++)
792 gpio_remove_key(&ddata
->data
[i
]);
794 input_unregister_device(input
);
796 /* If we have no platform data, we allocated pdata dynamically. */
797 if (!dev_get_platdata(&pdev
->dev
))
805 #ifdef CONFIG_PM_SLEEP
806 static int gpio_keys_suspend(struct device
*dev
)
808 struct gpio_keys_drvdata
*ddata
= dev_get_drvdata(dev
);
809 struct input_dev
*input
= ddata
->input
;
812 if (device_may_wakeup(dev
)) {
813 for (i
= 0; i
< ddata
->pdata
->nbuttons
; i
++) {
814 struct gpio_button_data
*bdata
= &ddata
->data
[i
];
815 if (bdata
->button
->wakeup
)
816 enable_irq_wake(bdata
->irq
);
819 mutex_lock(&input
->mutex
);
821 gpio_keys_close(input
);
822 mutex_unlock(&input
->mutex
);
828 static int gpio_keys_resume(struct device
*dev
)
830 struct gpio_keys_drvdata
*ddata
= dev_get_drvdata(dev
);
831 struct input_dev
*input
= ddata
->input
;
835 if (device_may_wakeup(dev
)) {
836 for (i
= 0; i
< ddata
->pdata
->nbuttons
; i
++) {
837 struct gpio_button_data
*bdata
= &ddata
->data
[i
];
838 if (bdata
->button
->wakeup
)
839 disable_irq_wake(bdata
->irq
);
842 mutex_lock(&input
->mutex
);
844 error
= gpio_keys_open(input
);
845 mutex_unlock(&input
->mutex
);
851 gpio_keys_report_state(ddata
);
856 static SIMPLE_DEV_PM_OPS(gpio_keys_pm_ops
, gpio_keys_suspend
, gpio_keys_resume
);
858 static struct platform_driver gpio_keys_device_driver
= {
859 .probe
= gpio_keys_probe
,
860 .remove
= gpio_keys_remove
,
863 .owner
= THIS_MODULE
,
864 .pm
= &gpio_keys_pm_ops
,
865 .of_match_table
= of_match_ptr(gpio_keys_of_match
),
869 static int __init
gpio_keys_init(void)
871 return platform_driver_register(&gpio_keys_device_driver
);
874 static void __exit
gpio_keys_exit(void)
876 platform_driver_unregister(&gpio_keys_device_driver
);
879 late_initcall(gpio_keys_init
);
880 module_exit(gpio_keys_exit
);
882 MODULE_LICENSE("GPL");
883 MODULE_AUTHOR("Phil Blundell <pb@handhelds.org>");
884 MODULE_DESCRIPTION("Keyboard driver for GPIOs");
885 MODULE_ALIAS("platform:gpio-keys");