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 struct gpio_button_data data[0];
46 * SYSFS interface for enabling/disabling keys and switches:
48 * There are 4 attributes under /sys/devices/platform/gpio-keys/
49 * keys [ro] - bitmap of keys (EV_KEY) which can be
51 * switches [ro] - bitmap of switches (EV_SW) which can be
53 * disabled_keys [rw] - bitmap of keys currently disabled
54 * disabled_switches [rw] - bitmap of switches currently disabled
56 * Userland can change these values and hence disable event generation
57 * for each key (or switch). Disabling a key means its interrupt line
60 * For example, if we have following switches set up as gpio-keys:
62 * SW_CAMERA_LENS_COVER = 9
63 * SW_KEYPAD_SLIDE = 10
64 * SW_FRONT_PROXIMITY = 11
65 * This is read from switches:
67 * Next we want to disable proximity (11) and dock (5), we write:
69 * to file disabled_switches. Now proximity and dock IRQs are disabled.
70 * This can be verified by reading the file disabled_switches:
72 * If we now want to enable proximity (11) switch we write:
74 * to disabled_switches.
76 * We can disable only those keys which don't allow sharing the irq.
80 * get_n_events_by_type() - returns maximum number of events per @type
81 * @type: type of button (%EV_KEY, %EV_SW)
83 * Return value of this function can be used to allocate bitmap
84 * large enough to hold all bits for given type.
86 static inline int get_n_events_by_type(int type)
88 BUG_ON(type != EV_SW && type != EV_KEY);
90 return (type == EV_KEY) ? KEY_CNT : SW_CNT;
94 * gpio_keys_disable_button() - disables given GPIO button
95 * @bdata: button data for button to be disabled
97 * Disables button pointed by @bdata. This is done by masking
98 * IRQ line. After this function is called, button won't generate
99 * input events anymore. Note that one can only disable buttons
100 * that don't share IRQs.
102 * Make sure that @bdata->disable_lock is locked when entering
103 * this function to avoid races when concurrent threads are
104 * disabling buttons at the same time.
106 static void gpio_keys_disable_button(struct gpio_button_data *bdata)
108 if (!bdata->disabled) {
110 * Disable IRQ and possible debouncing timer.
112 disable_irq(gpio_to_irq(bdata->button->gpio));
113 if (bdata->timer_debounce)
114 del_timer_sync(&bdata->timer);
116 bdata->disabled = true;
121 * gpio_keys_enable_button() - enables given GPIO button
122 * @bdata: button data for button to be disabled
124 * Enables given button pointed by @bdata.
126 * Make sure that @bdata->disable_lock is locked when entering
127 * this function to avoid races with concurrent threads trying
128 * to enable the same button at the same time.
130 static void gpio_keys_enable_button(struct gpio_button_data *bdata)
132 if (bdata->disabled) {
133 enable_irq(gpio_to_irq(bdata->button->gpio));
134 bdata->disabled = false;
139 * gpio_keys_attr_show_helper() - fill in stringified bitmap of buttons
140 * @ddata: pointer to drvdata
141 * @buf: buffer where stringified bitmap is written
142 * @type: button type (%EV_KEY, %EV_SW)
143 * @only_disabled: does caller want only those buttons that are
144 * currently disabled or all buttons that can be
147 * This function writes buttons that can be disabled to @buf. If
148 * @only_disabled is true, then @buf contains only those buttons
149 * that are currently disabled. Returns 0 on success or negative
152 static ssize_t gpio_keys_attr_show_helper(struct gpio_keys_drvdata *ddata,
153 char *buf, unsigned int type,
156 int n_events = get_n_events_by_type(type);
161 bits = kcalloc(BITS_TO_LONGS(n_events), sizeof(*bits), GFP_KERNEL);
165 for (i = 0; i < ddata->n_buttons; i++) {
166 struct gpio_button_data *bdata = &ddata->data[i];
168 if (bdata->button->type != type)
171 if (only_disabled && !bdata->disabled)
174 __set_bit(bdata->button->code, bits);
177 ret = bitmap_scnlistprintf(buf, PAGE_SIZE - 2, bits, n_events);
187 * gpio_keys_attr_store_helper() - enable/disable buttons based on given bitmap
188 * @ddata: pointer to drvdata
189 * @buf: buffer from userspace that contains stringified bitmap
190 * @type: button type (%EV_KEY, %EV_SW)
192 * This function parses stringified bitmap from @buf and disables/enables
193 * GPIO buttons accordinly. Returns 0 on success and negative error
196 static ssize_t gpio_keys_attr_store_helper(struct gpio_keys_drvdata *ddata,
197 const char *buf, unsigned int type)
199 int n_events = get_n_events_by_type(type);
204 bits = kcalloc(BITS_TO_LONGS(n_events), sizeof(*bits), GFP_KERNEL);
208 error = bitmap_parselist(buf, bits, n_events);
213 for (i = 0; i < ddata->n_buttons; i++) {
214 struct gpio_button_data *bdata = &ddata->data[i];
216 if (bdata->button->type != type)
219 if (test_bit(bdata->button->code, bits) &&
220 !bdata->button->can_disable) {
226 mutex_lock(&ddata->disable_lock);
228 for (i = 0; i < ddata->n_buttons; i++) {
229 struct gpio_button_data *bdata = &ddata->data[i];
231 if (bdata->button->type != type)
234 if (test_bit(bdata->button->code, bits))
235 gpio_keys_disable_button(bdata);
237 gpio_keys_enable_button(bdata);
240 mutex_unlock(&ddata->disable_lock);
247 #define ATTR_SHOW_FN(name, type, only_disabled) \
248 static ssize_t gpio_keys_show_##name(struct device *dev, \
249 struct device_attribute *attr, \
252 struct platform_device *pdev = to_platform_device(dev); \
253 struct gpio_keys_drvdata *ddata = platform_get_drvdata(pdev); \
255 return gpio_keys_attr_show_helper(ddata, buf, \
256 type, only_disabled); \
259 ATTR_SHOW_FN(keys, EV_KEY, false);
260 ATTR_SHOW_FN(switches, EV_SW, false);
261 ATTR_SHOW_FN(disabled_keys, EV_KEY, true);
262 ATTR_SHOW_FN(disabled_switches, EV_SW, true);
267 * /sys/devices/platform/gpio-keys/keys [ro]
268 * /sys/devices/platform/gpio-keys/switches [ro]
270 static DEVICE_ATTR(keys, S_IRUGO, gpio_keys_show_keys, NULL);
271 static DEVICE_ATTR(switches, S_IRUGO, gpio_keys_show_switches, NULL);
273 #define ATTR_STORE_FN(name, type) \
274 static ssize_t gpio_keys_store_##name(struct device *dev, \
275 struct device_attribute *attr, \
279 struct platform_device *pdev = to_platform_device(dev); \
280 struct gpio_keys_drvdata *ddata = platform_get_drvdata(pdev); \
283 error = gpio_keys_attr_store_helper(ddata, buf, type); \
290 ATTR_STORE_FN(disabled_keys, EV_KEY);
291 ATTR_STORE_FN(disabled_switches, EV_SW);
296 * /sys/devices/platform/gpio-keys/disabled_keys [rw]
297 * /sys/devices/platform/gpio-keys/disables_switches [rw]
299 static DEVICE_ATTR(disabled_keys, S_IWUSR | S_IRUGO,
300 gpio_keys_show_disabled_keys,
301 gpio_keys_store_disabled_keys);
302 static DEVICE_ATTR(disabled_switches, S_IWUSR | S_IRUGO,
303 gpio_keys_show_disabled_switches,
304 gpio_keys_store_disabled_switches);
306 static struct attribute *gpio_keys_attrs[] = {
308 &dev_attr_switches.attr,
309 &dev_attr_disabled_keys.attr,
310 &dev_attr_disabled_switches.attr,
314 static struct attribute_group gpio_keys_attr_group = {
315 .attrs = gpio_keys_attrs,
318 static void gpio_keys_report_event(struct gpio_button_data *bdata)
320 struct gpio_keys_button *button = bdata->button;
321 struct input_dev *input = bdata->input;
322 unsigned int type = button->type ?: EV_KEY;
323 int state = (gpio_get_value(button->gpio) ? 1 : 0) ^ button->active_low;
325 input_event(input, type, button->code, !!state);
329 static void gpio_keys_work_func(struct work_struct *work)
331 struct gpio_button_data *bdata =
332 container_of(work, struct gpio_button_data, work);
334 gpio_keys_report_event(bdata);
337 static void gpio_keys_timer(unsigned long _data)
339 struct gpio_button_data *data = (struct gpio_button_data *)_data;
341 schedule_work(&data->work);
344 static irqreturn_t gpio_keys_isr(int irq, void *dev_id)
346 struct gpio_button_data *bdata = dev_id;
347 struct gpio_keys_button *button = bdata->button;
349 BUG_ON(irq != gpio_to_irq(button->gpio));
351 if (bdata->timer_debounce)
352 mod_timer(&bdata->timer,
353 jiffies + msecs_to_jiffies(bdata->timer_debounce));
355 schedule_work(&bdata->work);
360 static int __devinit gpio_keys_setup_key(struct platform_device *pdev,
361 struct gpio_button_data *bdata,
362 struct gpio_keys_button *button)
364 char *desc = button->desc ? button->desc : "gpio_keys";
365 struct device *dev = &pdev->dev;
366 unsigned long irqflags;
369 setup_timer(&bdata->timer, gpio_keys_timer, (unsigned long)bdata);
370 INIT_WORK(&bdata->work, gpio_keys_work_func);
372 error = gpio_request(button->gpio, desc);
374 dev_err(dev, "failed to request GPIO %d, error %d\n",
375 button->gpio, error);
379 error = gpio_direction_input(button->gpio);
381 dev_err(dev, "failed to configure"
382 " direction for GPIO %d, error %d\n",
383 button->gpio, error);
387 if (button->debounce_interval) {
388 error = gpio_set_debounce(button->gpio,
389 button->debounce_interval * 1000);
390 /* use timer if gpiolib doesn't provide debounce */
392 bdata->timer_debounce = button->debounce_interval;
395 irq = gpio_to_irq(button->gpio);
398 dev_err(dev, "Unable to get irq number for GPIO %d, error %d\n",
399 button->gpio, error);
403 irqflags = IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING;
405 * If platform has specified that the button can be disabled,
406 * we don't want it to share the interrupt line.
408 if (!button->can_disable)
409 irqflags |= IRQF_SHARED;
411 error = request_irq(irq, gpio_keys_isr, irqflags, desc, bdata);
413 dev_err(dev, "Unable to claim irq %d; error %d\n",
421 gpio_free(button->gpio);
426 static int __devinit gpio_keys_probe(struct platform_device *pdev)
428 struct gpio_keys_platform_data *pdata = pdev->dev.platform_data;
429 struct gpio_keys_drvdata *ddata;
430 struct device *dev = &pdev->dev;
431 struct input_dev *input;
435 ddata = kzalloc(sizeof(struct gpio_keys_drvdata) +
436 pdata->nbuttons * sizeof(struct gpio_button_data),
438 input = input_allocate_device();
439 if (!ddata || !input) {
440 dev_err(dev, "failed to allocate state\n");
445 ddata->input = input;
446 ddata->n_buttons = pdata->nbuttons;
447 mutex_init(&ddata->disable_lock);
449 platform_set_drvdata(pdev, ddata);
451 input->name = pdev->name;
452 input->phys = "gpio-keys/input0";
453 input->dev.parent = &pdev->dev;
455 input->id.bustype = BUS_HOST;
456 input->id.vendor = 0x0001;
457 input->id.product = 0x0001;
458 input->id.version = 0x0100;
460 /* Enable auto repeat feature of Linux input subsystem */
462 __set_bit(EV_REP, input->evbit);
464 for (i = 0; i < pdata->nbuttons; i++) {
465 struct gpio_keys_button *button = &pdata->buttons[i];
466 struct gpio_button_data *bdata = &ddata->data[i];
467 unsigned int type = button->type ?: EV_KEY;
469 bdata->input = input;
470 bdata->button = button;
472 error = gpio_keys_setup_key(pdev, bdata, button);
479 input_set_capability(input, type, button->code);
482 error = sysfs_create_group(&pdev->dev.kobj, &gpio_keys_attr_group);
484 dev_err(dev, "Unable to export keys/switches, error: %d\n",
489 error = input_register_device(input);
491 dev_err(dev, "Unable to register input device, error: %d\n",
496 /* get current state of buttons */
497 for (i = 0; i < pdata->nbuttons; i++)
498 gpio_keys_report_event(&ddata->data[i]);
501 device_init_wakeup(&pdev->dev, wakeup);
506 sysfs_remove_group(&pdev->dev.kobj, &gpio_keys_attr_group);
509 free_irq(gpio_to_irq(pdata->buttons[i].gpio), &ddata->data[i]);
510 if (ddata->data[i].timer_debounce)
511 del_timer_sync(&ddata->data[i].timer);
512 cancel_work_sync(&ddata->data[i].work);
513 gpio_free(pdata->buttons[i].gpio);
516 platform_set_drvdata(pdev, NULL);
518 input_free_device(input);
524 static int __devexit gpio_keys_remove(struct platform_device *pdev)
526 struct gpio_keys_platform_data *pdata = pdev->dev.platform_data;
527 struct gpio_keys_drvdata *ddata = platform_get_drvdata(pdev);
528 struct input_dev *input = ddata->input;
531 sysfs_remove_group(&pdev->dev.kobj, &gpio_keys_attr_group);
533 device_init_wakeup(&pdev->dev, 0);
535 for (i = 0; i < pdata->nbuttons; i++) {
536 int irq = gpio_to_irq(pdata->buttons[i].gpio);
537 free_irq(irq, &ddata->data[i]);
538 if (ddata->data[i].timer_debounce)
539 del_timer_sync(&ddata->data[i].timer);
540 cancel_work_sync(&ddata->data[i].work);
541 gpio_free(pdata->buttons[i].gpio);
544 input_unregister_device(input);
551 static int gpio_keys_suspend(struct device *dev)
553 struct platform_device *pdev = to_platform_device(dev);
554 struct gpio_keys_platform_data *pdata = pdev->dev.platform_data;
557 if (device_may_wakeup(&pdev->dev)) {
558 for (i = 0; i < pdata->nbuttons; i++) {
559 struct gpio_keys_button *button = &pdata->buttons[i];
560 if (button->wakeup) {
561 int irq = gpio_to_irq(button->gpio);
562 enable_irq_wake(irq);
570 static int gpio_keys_resume(struct device *dev)
572 struct platform_device *pdev = to_platform_device(dev);
573 struct gpio_keys_drvdata *ddata = platform_get_drvdata(pdev);
574 struct gpio_keys_platform_data *pdata = pdev->dev.platform_data;
577 for (i = 0; i < pdata->nbuttons; i++) {
579 struct gpio_keys_button *button = &pdata->buttons[i];
580 if (button->wakeup && device_may_wakeup(&pdev->dev)) {
581 int irq = gpio_to_irq(button->gpio);
582 disable_irq_wake(irq);
585 gpio_keys_report_event(&ddata->data[i]);
587 input_sync(ddata->input);
592 static const struct dev_pm_ops gpio_keys_pm_ops = {
593 .suspend = gpio_keys_suspend,
594 .resume = gpio_keys_resume,
598 static struct platform_driver gpio_keys_device_driver = {
599 .probe = gpio_keys_probe,
600 .remove = __devexit_p(gpio_keys_remove),
603 .owner = THIS_MODULE,
605 .pm = &gpio_keys_pm_ops,
610 static int __init gpio_keys_init(void)
612 return platform_driver_register(&gpio_keys_device_driver);
615 static void __exit gpio_keys_exit(void)
617 platform_driver_unregister(&gpio_keys_device_driver);
620 module_init(gpio_keys_init);
621 module_exit(gpio_keys_exit);
623 MODULE_LICENSE("GPL");
624 MODULE_AUTHOR("Phil Blundell <pb@handhelds.org>");
625 MODULE_DESCRIPTION("Keyboard driver for CPU GPIOs");
626 MODULE_ALIAS("platform:gpio-keys");