2 * Driver for keys on GPIO lines capable of generating interrupts.
4 * Copyright 2005 Phil Blundell
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
11 #include <linux/module.h>
13 #include <linux/init.h>
15 #include <linux/interrupt.h>
16 #include <linux/irq.h>
17 #include <linux/sched.h>
19 #include <linux/slab.h>
20 #include <linux/sysctl.h>
21 #include <linux/proc_fs.h>
22 #include <linux/delay.h>
23 #include <linux/platform_device.h>
24 #include <linux/input.h>
25 #include <linux/gpio_keys.h>
26 #include <linux/workqueue.h>
27 #include <linux/gpio.h>
29 struct gpio_button_data {
30 struct gpio_keys_button *button;
31 struct input_dev *input;
32 struct timer_list timer;
33 struct work_struct work;
34 int timer_debounce; /* in msecs */
38 struct gpio_keys_drvdata {
39 struct input_dev *input;
40 struct mutex disable_lock;
41 unsigned int n_buttons;
42 int (*enable)(struct device *dev);
43 void (*disable)(struct device *dev);
44 struct gpio_button_data data[0];
48 * SYSFS interface for enabling/disabling keys and switches:
50 * There are 4 attributes under /sys/devices/platform/gpio-keys/
51 * keys [ro] - bitmap of keys (EV_KEY) which can be
53 * switches [ro] - bitmap of switches (EV_SW) which can be
55 * disabled_keys [rw] - bitmap of keys currently disabled
56 * disabled_switches [rw] - bitmap of switches currently disabled
58 * Userland can change these values and hence disable event generation
59 * for each key (or switch). Disabling a key means its interrupt line
62 * For example, if we have following switches set up as gpio-keys:
64 * SW_CAMERA_LENS_COVER = 9
65 * SW_KEYPAD_SLIDE = 10
66 * SW_FRONT_PROXIMITY = 11
67 * This is read from switches:
69 * Next we want to disable proximity (11) and dock (5), we write:
71 * to file disabled_switches. Now proximity and dock IRQs are disabled.
72 * This can be verified by reading the file disabled_switches:
74 * If we now want to enable proximity (11) switch we write:
76 * to disabled_switches.
78 * We can disable only those keys which don't allow sharing the irq.
82 * get_n_events_by_type() - returns maximum number of events per @type
83 * @type: type of button (%EV_KEY, %EV_SW)
85 * Return value of this function can be used to allocate bitmap
86 * large enough to hold all bits for given type.
88 static inline int get_n_events_by_type(int type)
90 BUG_ON(type != EV_SW && type != EV_KEY);
92 return (type == EV_KEY) ? KEY_CNT : SW_CNT;
96 * gpio_keys_disable_button() - disables given GPIO button
97 * @bdata: button data for button to be disabled
99 * Disables button pointed by @bdata. This is done by masking
100 * IRQ line. After this function is called, button won't generate
101 * input events anymore. Note that one can only disable buttons
102 * that don't share IRQs.
104 * Make sure that @bdata->disable_lock is locked when entering
105 * this function to avoid races when concurrent threads are
106 * disabling buttons at the same time.
108 static void gpio_keys_disable_button(struct gpio_button_data *bdata)
110 if (!bdata->disabled) {
112 * Disable IRQ and possible debouncing timer.
114 disable_irq(gpio_to_irq(bdata->button->gpio));
115 if (bdata->timer_debounce)
116 del_timer_sync(&bdata->timer);
118 bdata->disabled = true;
123 * gpio_keys_enable_button() - enables given GPIO button
124 * @bdata: button data for button to be disabled
126 * Enables given button pointed by @bdata.
128 * Make sure that @bdata->disable_lock is locked when entering
129 * this function to avoid races with concurrent threads trying
130 * to enable the same button at the same time.
132 static void gpio_keys_enable_button(struct gpio_button_data *bdata)
134 if (bdata->disabled) {
135 enable_irq(gpio_to_irq(bdata->button->gpio));
136 bdata->disabled = false;
141 * gpio_keys_attr_show_helper() - fill in stringified bitmap of buttons
142 * @ddata: pointer to drvdata
143 * @buf: buffer where stringified bitmap is written
144 * @type: button type (%EV_KEY, %EV_SW)
145 * @only_disabled: does caller want only those buttons that are
146 * currently disabled or all buttons that can be
149 * This function writes buttons that can be disabled to @buf. If
150 * @only_disabled is true, then @buf contains only those buttons
151 * that are currently disabled. Returns 0 on success or negative
154 static ssize_t gpio_keys_attr_show_helper(struct gpio_keys_drvdata *ddata,
155 char *buf, unsigned int type,
158 int n_events = get_n_events_by_type(type);
163 bits = kcalloc(BITS_TO_LONGS(n_events), sizeof(*bits), GFP_KERNEL);
167 for (i = 0; i < ddata->n_buttons; i++) {
168 struct gpio_button_data *bdata = &ddata->data[i];
170 if (bdata->button->type != type)
173 if (only_disabled && !bdata->disabled)
176 __set_bit(bdata->button->code, bits);
179 ret = bitmap_scnlistprintf(buf, PAGE_SIZE - 2, bits, n_events);
189 * gpio_keys_attr_store_helper() - enable/disable buttons based on given bitmap
190 * @ddata: pointer to drvdata
191 * @buf: buffer from userspace that contains stringified bitmap
192 * @type: button type (%EV_KEY, %EV_SW)
194 * This function parses stringified bitmap from @buf and disables/enables
195 * GPIO buttons accordinly. Returns 0 on success and negative error
198 static ssize_t gpio_keys_attr_store_helper(struct gpio_keys_drvdata *ddata,
199 const char *buf, unsigned int type)
201 int n_events = get_n_events_by_type(type);
206 bits = kcalloc(BITS_TO_LONGS(n_events), sizeof(*bits), GFP_KERNEL);
210 error = bitmap_parselist(buf, bits, n_events);
215 for (i = 0; i < ddata->n_buttons; i++) {
216 struct gpio_button_data *bdata = &ddata->data[i];
218 if (bdata->button->type != type)
221 if (test_bit(bdata->button->code, bits) &&
222 !bdata->button->can_disable) {
228 mutex_lock(&ddata->disable_lock);
230 for (i = 0; i < ddata->n_buttons; i++) {
231 struct gpio_button_data *bdata = &ddata->data[i];
233 if (bdata->button->type != type)
236 if (test_bit(bdata->button->code, bits))
237 gpio_keys_disable_button(bdata);
239 gpio_keys_enable_button(bdata);
242 mutex_unlock(&ddata->disable_lock);
249 #define ATTR_SHOW_FN(name, type, only_disabled) \
250 static ssize_t gpio_keys_show_##name(struct device *dev, \
251 struct device_attribute *attr, \
254 struct platform_device *pdev = to_platform_device(dev); \
255 struct gpio_keys_drvdata *ddata = platform_get_drvdata(pdev); \
257 return gpio_keys_attr_show_helper(ddata, buf, \
258 type, only_disabled); \
261 ATTR_SHOW_FN(keys, EV_KEY, false);
262 ATTR_SHOW_FN(switches, EV_SW, false);
263 ATTR_SHOW_FN(disabled_keys, EV_KEY, true);
264 ATTR_SHOW_FN(disabled_switches, EV_SW, true);
269 * /sys/devices/platform/gpio-keys/keys [ro]
270 * /sys/devices/platform/gpio-keys/switches [ro]
272 static DEVICE_ATTR(keys, S_IRUGO, gpio_keys_show_keys, NULL);
273 static DEVICE_ATTR(switches, S_IRUGO, gpio_keys_show_switches, NULL);
275 #define ATTR_STORE_FN(name, type) \
276 static ssize_t gpio_keys_store_##name(struct device *dev, \
277 struct device_attribute *attr, \
281 struct platform_device *pdev = to_platform_device(dev); \
282 struct gpio_keys_drvdata *ddata = platform_get_drvdata(pdev); \
285 error = gpio_keys_attr_store_helper(ddata, buf, type); \
292 ATTR_STORE_FN(disabled_keys, EV_KEY);
293 ATTR_STORE_FN(disabled_switches, EV_SW);
298 * /sys/devices/platform/gpio-keys/disabled_keys [rw]
299 * /sys/devices/platform/gpio-keys/disables_switches [rw]
301 static DEVICE_ATTR(disabled_keys, S_IWUSR | S_IRUGO,
302 gpio_keys_show_disabled_keys,
303 gpio_keys_store_disabled_keys);
304 static DEVICE_ATTR(disabled_switches, S_IWUSR | S_IRUGO,
305 gpio_keys_show_disabled_switches,
306 gpio_keys_store_disabled_switches);
308 static struct attribute *gpio_keys_attrs[] = {
310 &dev_attr_switches.attr,
311 &dev_attr_disabled_keys.attr,
312 &dev_attr_disabled_switches.attr,
316 static struct attribute_group gpio_keys_attr_group = {
317 .attrs = gpio_keys_attrs,
320 static void gpio_keys_report_event(struct gpio_button_data *bdata)
322 struct gpio_keys_button *button = bdata->button;
323 struct input_dev *input = bdata->input;
324 unsigned int type = button->type ?: EV_KEY;
325 int state = (gpio_get_value_cansleep(button->gpio) ? 1 : 0) ^ button->active_low;
327 if (type == EV_ABS) {
329 input_event(input, type, button->code, button->value);
331 input_event(input, type, button->code, !!state);
336 static void gpio_keys_work_func(struct work_struct *work)
338 struct gpio_button_data *bdata =
339 container_of(work, struct gpio_button_data, work);
341 gpio_keys_report_event(bdata);
344 static void gpio_keys_timer(unsigned long _data)
346 struct gpio_button_data *data = (struct gpio_button_data *)_data;
348 schedule_work(&data->work);
351 static irqreturn_t gpio_keys_isr(int irq, void *dev_id)
353 struct gpio_button_data *bdata = dev_id;
354 struct gpio_keys_button *button = bdata->button;
356 BUG_ON(irq != gpio_to_irq(button->gpio));
358 if (bdata->timer_debounce)
359 mod_timer(&bdata->timer,
360 jiffies + msecs_to_jiffies(bdata->timer_debounce));
362 schedule_work(&bdata->work);
367 static int __devinit gpio_keys_setup_key(struct platform_device *pdev,
368 struct gpio_button_data *bdata,
369 struct gpio_keys_button *button)
371 const char *desc = button->desc ? button->desc : "gpio_keys";
372 struct device *dev = &pdev->dev;
373 unsigned long irqflags;
376 setup_timer(&bdata->timer, gpio_keys_timer, (unsigned long)bdata);
377 INIT_WORK(&bdata->work, gpio_keys_work_func);
379 error = gpio_request(button->gpio, desc);
381 dev_err(dev, "failed to request GPIO %d, error %d\n",
382 button->gpio, error);
386 error = gpio_direction_input(button->gpio);
388 dev_err(dev, "failed to configure"
389 " direction for GPIO %d, error %d\n",
390 button->gpio, error);
394 if (button->debounce_interval) {
395 error = gpio_set_debounce(button->gpio,
396 button->debounce_interval * 1000);
397 /* use timer if gpiolib doesn't provide debounce */
399 bdata->timer_debounce = button->debounce_interval;
402 irq = gpio_to_irq(button->gpio);
405 dev_err(dev, "Unable to get irq number for GPIO %d, error %d\n",
406 button->gpio, error);
410 irqflags = IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING;
412 * If platform has specified that the button can be disabled,
413 * we don't want it to share the interrupt line.
415 if (!button->can_disable)
416 irqflags |= IRQF_SHARED;
418 error = request_any_context_irq(irq, gpio_keys_isr, irqflags, desc, bdata);
420 dev_err(dev, "Unable to claim irq %d; error %d\n",
428 gpio_free(button->gpio);
433 static int gpio_keys_open(struct input_dev *input)
435 struct gpio_keys_drvdata *ddata = input_get_drvdata(input);
437 return ddata->enable ? ddata->enable(input->dev.parent) : 0;
440 static void gpio_keys_close(struct input_dev *input)
442 struct gpio_keys_drvdata *ddata = input_get_drvdata(input);
445 ddata->disable(input->dev.parent);
448 static int __devinit gpio_keys_probe(struct platform_device *pdev)
450 struct gpio_keys_platform_data *pdata = pdev->dev.platform_data;
451 struct gpio_keys_drvdata *ddata;
452 struct device *dev = &pdev->dev;
453 struct input_dev *input;
457 ddata = kzalloc(sizeof(struct gpio_keys_drvdata) +
458 pdata->nbuttons * sizeof(struct gpio_button_data),
460 input = input_allocate_device();
461 if (!ddata || !input) {
462 dev_err(dev, "failed to allocate state\n");
467 ddata->input = input;
468 ddata->n_buttons = pdata->nbuttons;
469 ddata->enable = pdata->enable;
470 ddata->disable = pdata->disable;
471 mutex_init(&ddata->disable_lock);
473 platform_set_drvdata(pdev, ddata);
474 input_set_drvdata(input, ddata);
476 input->name = pdata->name ? : pdev->name;
477 input->phys = "gpio-keys/input0";
478 input->dev.parent = &pdev->dev;
479 input->open = gpio_keys_open;
480 input->close = gpio_keys_close;
482 input->id.bustype = BUS_HOST;
483 input->id.vendor = 0x0001;
484 input->id.product = 0x0001;
485 input->id.version = 0x0100;
487 /* Enable auto repeat feature of Linux input subsystem */
489 __set_bit(EV_REP, input->evbit);
491 for (i = 0; i < pdata->nbuttons; i++) {
492 struct gpio_keys_button *button = &pdata->buttons[i];
493 struct gpio_button_data *bdata = &ddata->data[i];
494 unsigned int type = button->type ?: EV_KEY;
496 bdata->input = input;
497 bdata->button = button;
499 error = gpio_keys_setup_key(pdev, bdata, button);
506 input_set_capability(input, type, button->code);
509 error = sysfs_create_group(&pdev->dev.kobj, &gpio_keys_attr_group);
511 dev_err(dev, "Unable to export keys/switches, error: %d\n",
516 error = input_register_device(input);
518 dev_err(dev, "Unable to register input device, error: %d\n",
523 /* get current state of buttons */
524 for (i = 0; i < pdata->nbuttons; i++)
525 gpio_keys_report_event(&ddata->data[i]);
528 device_init_wakeup(&pdev->dev, wakeup);
533 sysfs_remove_group(&pdev->dev.kobj, &gpio_keys_attr_group);
536 free_irq(gpio_to_irq(pdata->buttons[i].gpio), &ddata->data[i]);
537 if (ddata->data[i].timer_debounce)
538 del_timer_sync(&ddata->data[i].timer);
539 cancel_work_sync(&ddata->data[i].work);
540 gpio_free(pdata->buttons[i].gpio);
543 platform_set_drvdata(pdev, NULL);
545 input_free_device(input);
551 static int __devexit gpio_keys_remove(struct platform_device *pdev)
553 struct gpio_keys_platform_data *pdata = pdev->dev.platform_data;
554 struct gpio_keys_drvdata *ddata = platform_get_drvdata(pdev);
555 struct input_dev *input = ddata->input;
558 sysfs_remove_group(&pdev->dev.kobj, &gpio_keys_attr_group);
560 device_init_wakeup(&pdev->dev, 0);
562 for (i = 0; i < pdata->nbuttons; i++) {
563 int irq = gpio_to_irq(pdata->buttons[i].gpio);
564 free_irq(irq, &ddata->data[i]);
565 if (ddata->data[i].timer_debounce)
566 del_timer_sync(&ddata->data[i].timer);
567 cancel_work_sync(&ddata->data[i].work);
568 gpio_free(pdata->buttons[i].gpio);
571 input_unregister_device(input);
578 static int gpio_keys_suspend(struct device *dev)
580 struct platform_device *pdev = to_platform_device(dev);
581 struct gpio_keys_platform_data *pdata = pdev->dev.platform_data;
584 if (device_may_wakeup(&pdev->dev)) {
585 for (i = 0; i < pdata->nbuttons; i++) {
586 struct gpio_keys_button *button = &pdata->buttons[i];
587 if (button->wakeup) {
588 int irq = gpio_to_irq(button->gpio);
589 enable_irq_wake(irq);
597 static int gpio_keys_resume(struct device *dev)
599 struct platform_device *pdev = to_platform_device(dev);
600 struct gpio_keys_drvdata *ddata = platform_get_drvdata(pdev);
601 struct gpio_keys_platform_data *pdata = pdev->dev.platform_data;
604 for (i = 0; i < pdata->nbuttons; i++) {
606 struct gpio_keys_button *button = &pdata->buttons[i];
607 if (button->wakeup && device_may_wakeup(&pdev->dev)) {
608 int irq = gpio_to_irq(button->gpio);
609 disable_irq_wake(irq);
612 gpio_keys_report_event(&ddata->data[i]);
614 input_sync(ddata->input);
619 static const struct dev_pm_ops gpio_keys_pm_ops = {
620 .suspend = gpio_keys_suspend,
621 .resume = gpio_keys_resume,
625 static struct platform_driver gpio_keys_device_driver = {
626 .probe = gpio_keys_probe,
627 .remove = __devexit_p(gpio_keys_remove),
630 .owner = THIS_MODULE,
632 .pm = &gpio_keys_pm_ops,
637 static int __init gpio_keys_init(void)
639 return platform_driver_register(&gpio_keys_device_driver);
642 static void __exit gpio_keys_exit(void)
644 platform_driver_unregister(&gpio_keys_device_driver);
647 module_init(gpio_keys_init);
648 module_exit(gpio_keys_exit);
650 MODULE_LICENSE("GPL");
651 MODULE_AUTHOR("Phil Blundell <pb@handhelds.org>");
652 MODULE_DESCRIPTION("Keyboard driver for CPU GPIOs");
653 MODULE_ALIAS("platform:gpio-keys");