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 struct input_dev
*input
;
47 struct mutex disable_lock
;
48 unsigned int n_buttons
;
49 int (*enable
)(struct device
*dev
);
50 void (*disable
)(struct device
*dev
);
51 struct gpio_button_data data
[0];
55 * SYSFS interface for enabling/disabling keys and switches:
57 * There are 4 attributes under /sys/devices/platform/gpio-keys/
58 * keys [ro] - bitmap of keys (EV_KEY) which can be
60 * switches [ro] - bitmap of switches (EV_SW) which can be
62 * disabled_keys [rw] - bitmap of keys currently disabled
63 * disabled_switches [rw] - bitmap of switches currently disabled
65 * Userland can change these values and hence disable event generation
66 * for each key (or switch). Disabling a key means its interrupt line
69 * For example, if we have following switches set up as gpio-keys:
71 * SW_CAMERA_LENS_COVER = 9
72 * SW_KEYPAD_SLIDE = 10
73 * SW_FRONT_PROXIMITY = 11
74 * This is read from switches:
76 * Next we want to disable proximity (11) and dock (5), we write:
78 * to file disabled_switches. Now proximity and dock IRQs are disabled.
79 * This can be verified by reading the file disabled_switches:
81 * If we now want to enable proximity (11) switch we write:
83 * to disabled_switches.
85 * We can disable only those keys which don't allow sharing the irq.
89 * get_n_events_by_type() - returns maximum number of events per @type
90 * @type: type of button (%EV_KEY, %EV_SW)
92 * Return value of this function can be used to allocate bitmap
93 * large enough to hold all bits for given type.
95 static inline int get_n_events_by_type(int type
)
97 BUG_ON(type
!= EV_SW
&& type
!= EV_KEY
);
99 return (type
== EV_KEY
) ? KEY_CNT
: SW_CNT
;
103 * gpio_keys_disable_button() - disables given GPIO button
104 * @bdata: button data for button to be disabled
106 * Disables button pointed by @bdata. This is done by masking
107 * IRQ line. After this function is called, button won't generate
108 * input events anymore. Note that one can only disable buttons
109 * that don't share IRQs.
111 * Make sure that @bdata->disable_lock is locked when entering
112 * this function to avoid races when concurrent threads are
113 * disabling buttons at the same time.
115 static void gpio_keys_disable_button(struct gpio_button_data
*bdata
)
117 if (!bdata
->disabled
) {
119 * Disable IRQ and possible debouncing timer.
121 disable_irq(bdata
->irq
);
122 if (bdata
->timer_debounce
)
123 del_timer_sync(&bdata
->timer
);
125 bdata
->disabled
= true;
130 * gpio_keys_enable_button() - enables given GPIO button
131 * @bdata: button data for button to be disabled
133 * Enables given button pointed by @bdata.
135 * Make sure that @bdata->disable_lock is locked when entering
136 * this function to avoid races with concurrent threads trying
137 * to enable the same button at the same time.
139 static void gpio_keys_enable_button(struct gpio_button_data
*bdata
)
141 if (bdata
->disabled
) {
142 enable_irq(bdata
->irq
);
143 bdata
->disabled
= false;
148 * gpio_keys_attr_show_helper() - fill in stringified bitmap of buttons
149 * @ddata: pointer to drvdata
150 * @buf: buffer where stringified bitmap is written
151 * @type: button type (%EV_KEY, %EV_SW)
152 * @only_disabled: does caller want only those buttons that are
153 * currently disabled or all buttons that can be
156 * This function writes buttons that can be disabled to @buf. If
157 * @only_disabled is true, then @buf contains only those buttons
158 * that are currently disabled. Returns 0 on success or negative
161 static ssize_t
gpio_keys_attr_show_helper(struct gpio_keys_drvdata
*ddata
,
162 char *buf
, unsigned int type
,
165 int n_events
= get_n_events_by_type(type
);
170 bits
= kcalloc(BITS_TO_LONGS(n_events
), sizeof(*bits
), GFP_KERNEL
);
174 for (i
= 0; i
< ddata
->n_buttons
; i
++) {
175 struct gpio_button_data
*bdata
= &ddata
->data
[i
];
177 if (bdata
->button
->type
!= type
)
180 if (only_disabled
&& !bdata
->disabled
)
183 __set_bit(bdata
->button
->code
, bits
);
186 ret
= bitmap_scnlistprintf(buf
, PAGE_SIZE
- 2, bits
, n_events
);
196 * gpio_keys_attr_store_helper() - enable/disable buttons based on given bitmap
197 * @ddata: pointer to drvdata
198 * @buf: buffer from userspace that contains stringified bitmap
199 * @type: button type (%EV_KEY, %EV_SW)
201 * This function parses stringified bitmap from @buf and disables/enables
202 * GPIO buttons accordingly. Returns 0 on success and negative error
205 static ssize_t
gpio_keys_attr_store_helper(struct gpio_keys_drvdata
*ddata
,
206 const char *buf
, unsigned int type
)
208 int n_events
= get_n_events_by_type(type
);
213 bits
= kcalloc(BITS_TO_LONGS(n_events
), sizeof(*bits
), GFP_KERNEL
);
217 error
= bitmap_parselist(buf
, bits
, n_events
);
222 for (i
= 0; i
< ddata
->n_buttons
; i
++) {
223 struct gpio_button_data
*bdata
= &ddata
->data
[i
];
225 if (bdata
->button
->type
!= type
)
228 if (test_bit(bdata
->button
->code
, bits
) &&
229 !bdata
->button
->can_disable
) {
235 mutex_lock(&ddata
->disable_lock
);
237 for (i
= 0; i
< ddata
->n_buttons
; i
++) {
238 struct gpio_button_data
*bdata
= &ddata
->data
[i
];
240 if (bdata
->button
->type
!= type
)
243 if (test_bit(bdata
->button
->code
, bits
))
244 gpio_keys_disable_button(bdata
);
246 gpio_keys_enable_button(bdata
);
249 mutex_unlock(&ddata
->disable_lock
);
256 #define ATTR_SHOW_FN(name, type, only_disabled) \
257 static ssize_t gpio_keys_show_##name(struct device *dev, \
258 struct device_attribute *attr, \
261 struct platform_device *pdev = to_platform_device(dev); \
262 struct gpio_keys_drvdata *ddata = platform_get_drvdata(pdev); \
264 return gpio_keys_attr_show_helper(ddata, buf, \
265 type, only_disabled); \
268 ATTR_SHOW_FN(keys
, EV_KEY
, false);
269 ATTR_SHOW_FN(switches
, EV_SW
, false);
270 ATTR_SHOW_FN(disabled_keys
, EV_KEY
, true);
271 ATTR_SHOW_FN(disabled_switches
, EV_SW
, true);
276 * /sys/devices/platform/gpio-keys/keys [ro]
277 * /sys/devices/platform/gpio-keys/switches [ro]
279 static DEVICE_ATTR(keys
, S_IRUGO
, gpio_keys_show_keys
, NULL
);
280 static DEVICE_ATTR(switches
, S_IRUGO
, gpio_keys_show_switches
, NULL
);
282 #define ATTR_STORE_FN(name, type) \
283 static ssize_t gpio_keys_store_##name(struct device *dev, \
284 struct device_attribute *attr, \
288 struct platform_device *pdev = to_platform_device(dev); \
289 struct gpio_keys_drvdata *ddata = platform_get_drvdata(pdev); \
292 error = gpio_keys_attr_store_helper(ddata, buf, type); \
299 ATTR_STORE_FN(disabled_keys
, EV_KEY
);
300 ATTR_STORE_FN(disabled_switches
, EV_SW
);
305 * /sys/devices/platform/gpio-keys/disabled_keys [rw]
306 * /sys/devices/platform/gpio-keys/disables_switches [rw]
308 static DEVICE_ATTR(disabled_keys
, S_IWUSR
| S_IRUGO
,
309 gpio_keys_show_disabled_keys
,
310 gpio_keys_store_disabled_keys
);
311 static DEVICE_ATTR(disabled_switches
, S_IWUSR
| S_IRUGO
,
312 gpio_keys_show_disabled_switches
,
313 gpio_keys_store_disabled_switches
);
315 static struct attribute
*gpio_keys_attrs
[] = {
317 &dev_attr_switches
.attr
,
318 &dev_attr_disabled_keys
.attr
,
319 &dev_attr_disabled_switches
.attr
,
323 static struct attribute_group gpio_keys_attr_group
= {
324 .attrs
= gpio_keys_attrs
,
327 static void gpio_keys_gpio_report_event(struct gpio_button_data
*bdata
)
329 const struct gpio_keys_button
*button
= bdata
->button
;
330 struct input_dev
*input
= bdata
->input
;
331 unsigned int type
= button
->type
?: EV_KEY
;
332 int state
= (gpio_get_value_cansleep(button
->gpio
) ? 1 : 0) ^ button
->active_low
;
334 if (type
== EV_ABS
) {
336 input_event(input
, type
, button
->code
, button
->value
);
338 input_event(input
, type
, button
->code
, !!state
);
343 static void gpio_keys_gpio_work_func(struct work_struct
*work
)
345 struct gpio_button_data
*bdata
=
346 container_of(work
, struct gpio_button_data
, work
);
348 gpio_keys_gpio_report_event(bdata
);
351 static void gpio_keys_gpio_timer(unsigned long _data
)
353 struct gpio_button_data
*bdata
= (struct gpio_button_data
*)_data
;
355 schedule_work(&bdata
->work
);
358 static irqreturn_t
gpio_keys_gpio_isr(int irq
, void *dev_id
)
360 struct gpio_button_data
*bdata
= dev_id
;
362 BUG_ON(irq
!= bdata
->irq
);
364 if (bdata
->timer_debounce
)
365 mod_timer(&bdata
->timer
,
366 jiffies
+ msecs_to_jiffies(bdata
->timer_debounce
));
368 schedule_work(&bdata
->work
);
373 static void gpio_keys_irq_timer(unsigned long _data
)
375 struct gpio_button_data
*bdata
= (struct gpio_button_data
*)_data
;
376 struct input_dev
*input
= bdata
->input
;
379 spin_lock_irqsave(&bdata
->lock
, flags
);
380 if (bdata
->key_pressed
) {
381 input_event(input
, EV_KEY
, bdata
->button
->code
, 0);
383 bdata
->key_pressed
= false;
385 spin_unlock_irqrestore(&bdata
->lock
, flags
);
388 static irqreturn_t
gpio_keys_irq_isr(int irq
, void *dev_id
)
390 struct gpio_button_data
*bdata
= dev_id
;
391 const struct gpio_keys_button
*button
= bdata
->button
;
392 struct input_dev
*input
= bdata
->input
;
395 BUG_ON(irq
!= bdata
->irq
);
397 spin_lock_irqsave(&bdata
->lock
, flags
);
399 if (!bdata
->key_pressed
) {
400 input_event(input
, EV_KEY
, button
->code
, 1);
403 if (!bdata
->timer_debounce
) {
404 input_event(input
, EV_KEY
, button
->code
, 0);
409 bdata
->key_pressed
= true;
412 if (bdata
->timer_debounce
)
413 mod_timer(&bdata
->timer
,
414 jiffies
+ msecs_to_jiffies(bdata
->timer_debounce
));
416 spin_unlock_irqrestore(&bdata
->lock
, flags
);
420 static int __devinit
gpio_keys_setup_key(struct platform_device
*pdev
,
421 struct input_dev
*input
,
422 struct gpio_button_data
*bdata
,
423 const struct gpio_keys_button
*button
)
425 const char *desc
= button
->desc
? button
->desc
: "gpio_keys";
426 struct device
*dev
= &pdev
->dev
;
428 unsigned long irqflags
;
431 bdata
->input
= input
;
432 bdata
->button
= button
;
433 spin_lock_init(&bdata
->lock
);
435 if (gpio_is_valid(button
->gpio
)) {
437 error
= gpio_request(button
->gpio
, desc
);
439 dev_err(dev
, "Failed to request GPIO %d, error %d\n",
440 button
->gpio
, error
);
444 error
= gpio_direction_input(button
->gpio
);
447 "Failed to configure direction for GPIO %d, error %d\n",
448 button
->gpio
, error
);
452 if (button
->debounce_interval
) {
453 error
= gpio_set_debounce(button
->gpio
,
454 button
->debounce_interval
* 1000);
455 /* use timer if gpiolib doesn't provide debounce */
457 bdata
->timer_debounce
=
458 button
->debounce_interval
;
461 irq
= gpio_to_irq(button
->gpio
);
465 "Unable to get irq number for GPIO %d, error %d\n",
466 button
->gpio
, error
);
471 INIT_WORK(&bdata
->work
, gpio_keys_gpio_work_func
);
472 setup_timer(&bdata
->timer
,
473 gpio_keys_gpio_timer
, (unsigned long)bdata
);
475 isr
= gpio_keys_gpio_isr
;
476 irqflags
= IRQF_TRIGGER_RISING
| IRQF_TRIGGER_FALLING
;
480 dev_err(dev
, "No IRQ specified\n");
483 bdata
->irq
= button
->irq
;
485 if (button
->type
&& button
->type
!= EV_KEY
) {
486 dev_err(dev
, "Only EV_KEY allowed for IRQ buttons.\n");
490 bdata
->timer_debounce
= button
->debounce_interval
;
491 setup_timer(&bdata
->timer
,
492 gpio_keys_irq_timer
, (unsigned long)bdata
);
494 isr
= gpio_keys_irq_isr
;
498 input_set_capability(input
, button
->type
?: EV_KEY
, button
->code
);
501 * If platform has specified that the button can be disabled,
502 * we don't want it to share the interrupt line.
504 if (!button
->can_disable
)
505 irqflags
|= IRQF_SHARED
;
507 error
= request_any_context_irq(bdata
->irq
, isr
, irqflags
, desc
, bdata
);
509 dev_err(dev
, "Unable to claim irq %d; error %d\n",
517 if (gpio_is_valid(button
->gpio
))
518 gpio_free(button
->gpio
);
523 static int gpio_keys_open(struct input_dev
*input
)
525 struct gpio_keys_drvdata
*ddata
= input_get_drvdata(input
);
527 return ddata
->enable
? ddata
->enable(input
->dev
.parent
) : 0;
530 static void gpio_keys_close(struct input_dev
*input
)
532 struct gpio_keys_drvdata
*ddata
= input_get_drvdata(input
);
535 ddata
->disable(input
->dev
.parent
);
539 * Handlers for alternative sources of platform_data
543 * Translate OpenFirmware node properties into platform_data
545 static int gpio_keys_get_devtree_pdata(struct device
*dev
,
546 struct gpio_keys_platform_data
*pdata
)
548 struct device_node
*node
, *pp
;
550 struct gpio_keys_button
*buttons
;
557 memset(pdata
, 0, sizeof *pdata
);
559 pdata
->rep
= !!of_get_property(node
, "autorepeat", NULL
);
561 /* First count the subnodes */
564 while ((pp
= of_get_next_child(node
, pp
)))
567 if (pdata
->nbuttons
== 0)
570 buttons
= kzalloc(pdata
->nbuttons
* (sizeof *buttons
), GFP_KERNEL
);
576 while ((pp
= of_get_next_child(node
, pp
))) {
577 enum of_gpio_flags flags
;
579 if (!of_find_property(pp
, "gpios", NULL
)) {
581 dev_warn(dev
, "Found button without gpios\n");
584 buttons
[i
].gpio
= of_get_gpio_flags(pp
, 0, &flags
);
585 buttons
[i
].active_low
= flags
& OF_GPIO_ACTIVE_LOW
;
587 if (of_property_read_u32(pp
, "linux,code", ®
)) {
588 dev_err(dev
, "Button without keycode: 0x%x\n", buttons
[i
].gpio
);
591 buttons
[i
].code
= reg
;
593 buttons
[i
].desc
= of_get_property(pp
, "label", NULL
);
595 if (of_property_read_u32(pp
, "linux,input-type", ®
) == 0)
596 buttons
[i
].type
= reg
;
598 buttons
[i
].type
= EV_KEY
;
600 buttons
[i
].wakeup
= !!of_get_property(pp
, "gpio-key,wakeup", NULL
);
602 if (of_property_read_u32(pp
, "debounce-interval", ®
) == 0)
603 buttons
[i
].debounce_interval
= reg
;
605 buttons
[i
].debounce_interval
= 5;
610 pdata
->buttons
= buttons
;
619 static struct of_device_id gpio_keys_of_match
[] = {
620 { .compatible
= "gpio-keys", },
623 MODULE_DEVICE_TABLE(of
, gpio_keys_of_match
);
627 static int gpio_keys_get_devtree_pdata(struct device
*dev
,
628 struct gpio_keys_platform_data
*altp
)
633 #define gpio_keys_of_match NULL
637 static void gpio_remove_key(struct gpio_button_data
*bdata
)
639 free_irq(bdata
->irq
, bdata
);
640 if (bdata
->timer_debounce
)
641 del_timer_sync(&bdata
->timer
);
642 cancel_work_sync(&bdata
->work
);
643 if (gpio_is_valid(bdata
->button
->gpio
))
644 gpio_free(bdata
->button
->gpio
);
647 static int __devinit
gpio_keys_probe(struct platform_device
*pdev
)
649 const struct gpio_keys_platform_data
*pdata
= pdev
->dev
.platform_data
;
650 struct gpio_keys_drvdata
*ddata
;
651 struct device
*dev
= &pdev
->dev
;
652 struct gpio_keys_platform_data alt_pdata
;
653 struct input_dev
*input
;
658 error
= gpio_keys_get_devtree_pdata(dev
, &alt_pdata
);
664 ddata
= kzalloc(sizeof(struct gpio_keys_drvdata
) +
665 pdata
->nbuttons
* sizeof(struct gpio_button_data
),
667 input
= input_allocate_device();
668 if (!ddata
|| !input
) {
669 dev_err(dev
, "failed to allocate state\n");
674 ddata
->input
= input
;
675 ddata
->n_buttons
= pdata
->nbuttons
;
676 ddata
->enable
= pdata
->enable
;
677 ddata
->disable
= pdata
->disable
;
678 mutex_init(&ddata
->disable_lock
);
680 platform_set_drvdata(pdev
, ddata
);
681 input_set_drvdata(input
, ddata
);
683 input
->name
= pdata
->name
? : pdev
->name
;
684 input
->phys
= "gpio-keys/input0";
685 input
->dev
.parent
= &pdev
->dev
;
686 input
->open
= gpio_keys_open
;
687 input
->close
= gpio_keys_close
;
689 input
->id
.bustype
= BUS_HOST
;
690 input
->id
.vendor
= 0x0001;
691 input
->id
.product
= 0x0001;
692 input
->id
.version
= 0x0100;
694 /* Enable auto repeat feature of Linux input subsystem */
696 __set_bit(EV_REP
, input
->evbit
);
698 for (i
= 0; i
< pdata
->nbuttons
; i
++) {
699 const struct gpio_keys_button
*button
= &pdata
->buttons
[i
];
700 struct gpio_button_data
*bdata
= &ddata
->data
[i
];
702 error
= gpio_keys_setup_key(pdev
, input
, bdata
, button
);
710 error
= sysfs_create_group(&pdev
->dev
.kobj
, &gpio_keys_attr_group
);
712 dev_err(dev
, "Unable to export keys/switches, error: %d\n",
717 error
= input_register_device(input
);
719 dev_err(dev
, "Unable to register input device, error: %d\n",
724 /* get current state of buttons that are connected to GPIOs */
725 for (i
= 0; i
< pdata
->nbuttons
; i
++) {
726 struct gpio_button_data
*bdata
= &ddata
->data
[i
];
727 if (gpio_is_valid(bdata
->button
->gpio
))
728 gpio_keys_gpio_report_event(bdata
);
732 device_init_wakeup(&pdev
->dev
, wakeup
);
737 sysfs_remove_group(&pdev
->dev
.kobj
, &gpio_keys_attr_group
);
740 gpio_remove_key(&ddata
->data
[i
]);
742 platform_set_drvdata(pdev
, NULL
);
744 input_free_device(input
);
746 /* If we have no platform_data, we allocated buttons dynamically. */
747 if (!pdev
->dev
.platform_data
)
748 kfree(pdata
->buttons
);
753 static int __devexit
gpio_keys_remove(struct platform_device
*pdev
)
755 struct gpio_keys_drvdata
*ddata
= platform_get_drvdata(pdev
);
756 struct input_dev
*input
= ddata
->input
;
759 sysfs_remove_group(&pdev
->dev
.kobj
, &gpio_keys_attr_group
);
761 device_init_wakeup(&pdev
->dev
, 0);
763 for (i
= 0; i
< ddata
->n_buttons
; i
++)
764 gpio_remove_key(&ddata
->data
[i
]);
766 input_unregister_device(input
);
769 * If we had no platform_data, we allocated buttons dynamically, and
770 * must free them here. ddata->data[0].button is the pointer to the
771 * beginning of the allocated array.
773 if (!pdev
->dev
.platform_data
)
774 kfree(ddata
->data
[0].button
);
781 #ifdef CONFIG_PM_SLEEP
782 static int gpio_keys_suspend(struct device
*dev
)
784 struct gpio_keys_drvdata
*ddata
= dev_get_drvdata(dev
);
787 if (device_may_wakeup(dev
)) {
788 for (i
= 0; i
< ddata
->n_buttons
; i
++) {
789 struct gpio_button_data
*bdata
= &ddata
->data
[i
];
790 if (bdata
->button
->wakeup
)
791 enable_irq_wake(bdata
->irq
);
798 static int gpio_keys_resume(struct device
*dev
)
800 struct gpio_keys_drvdata
*ddata
= dev_get_drvdata(dev
);
803 for (i
= 0; i
< ddata
->n_buttons
; i
++) {
804 struct gpio_button_data
*bdata
= &ddata
->data
[i
];
805 if (bdata
->button
->wakeup
&& device_may_wakeup(dev
))
806 disable_irq_wake(bdata
->irq
);
808 if (gpio_is_valid(bdata
->button
->gpio
))
809 gpio_keys_gpio_report_event(bdata
);
811 input_sync(ddata
->input
);
817 static SIMPLE_DEV_PM_OPS(gpio_keys_pm_ops
, gpio_keys_suspend
, gpio_keys_resume
);
819 static struct platform_driver gpio_keys_device_driver
= {
820 .probe
= gpio_keys_probe
,
821 .remove
= __devexit_p(gpio_keys_remove
),
824 .owner
= THIS_MODULE
,
825 .pm
= &gpio_keys_pm_ops
,
826 .of_match_table
= gpio_keys_of_match
,
830 static int __init
gpio_keys_init(void)
832 return platform_driver_register(&gpio_keys_device_driver
);
835 static void __exit
gpio_keys_exit(void)
837 platform_driver_unregister(&gpio_keys_device_driver
);
840 late_initcall(gpio_keys_init
);
841 module_exit(gpio_keys_exit
);
843 MODULE_LICENSE("GPL");
844 MODULE_AUTHOR("Phil Blundell <pb@handhelds.org>");
845 MODULE_DESCRIPTION("Keyboard driver for GPIOs");
846 MODULE_ALIAS("platform:gpio-keys");