/* * Driver for keys on GPIO lines capable of generating interrupts. * * Copyright 2005 Phil Blundell * Copyright 2010, 2011 David Jander * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include struct gpio_button_data { const struct gpio_keys_button *button; struct input_dev *input; struct gpio_desc *gpiod; struct timer_list release_timer; unsigned int release_delay; /* in msecs, for IRQ-only buttons */ struct delayed_work work; unsigned int software_debounce; /* in msecs, for GPIO-driven buttons */ unsigned int irq; spinlock_t lock; bool disabled; bool key_pressed; }; struct gpio_keys_drvdata { const struct gpio_keys_platform_data *pdata; struct input_dev *input; struct mutex disable_lock; struct gpio_button_data data[0]; }; /* * SYSFS interface for enabling/disabling keys and switches: * * There are 4 attributes under /sys/devices/platform/gpio-keys/ * keys [ro] - bitmap of keys (EV_KEY) which can be * disabled * switches [ro] - bitmap of switches (EV_SW) which can be * disabled * disabled_keys [rw] - bitmap of keys currently disabled * disabled_switches [rw] - bitmap of switches currently disabled * * Userland can change these values and hence disable event generation * for each key (or switch). Disabling a key means its interrupt line * is disabled. * * For example, if we have following switches set up as gpio-keys: * SW_DOCK = 5 * SW_CAMERA_LENS_COVER = 9 * SW_KEYPAD_SLIDE = 10 * SW_FRONT_PROXIMITY = 11 * This is read from switches: * 11-9,5 * Next we want to disable proximity (11) and dock (5), we write: * 11,5 * to file disabled_switches. Now proximity and dock IRQs are disabled. * This can be verified by reading the file disabled_switches: * 11,5 * If we now want to enable proximity (11) switch we write: * 5 * to disabled_switches. * * We can disable only those keys which don't allow sharing the irq. */ /** * get_n_events_by_type() - returns maximum number of events per @type * @type: type of button (%EV_KEY, %EV_SW) * * Return value of this function can be used to allocate bitmap * large enough to hold all bits for given type. */ static int get_n_events_by_type(int type) { BUG_ON(type != EV_SW && type != EV_KEY); return (type == EV_KEY) ? KEY_CNT : SW_CNT; } /** * get_bm_events_by_type() - returns bitmap of supported events per @type * @input: input device from which bitmap is retrieved * @type: type of button (%EV_KEY, %EV_SW) * * Return value of this function can be used to allocate bitmap * large enough to hold all bits for given type. */ static const unsigned long *get_bm_events_by_type(struct input_dev *dev, int type) { BUG_ON(type != EV_SW && type != EV_KEY); return (type == EV_KEY) ? dev->keybit : dev->swbit; } /** * gpio_keys_disable_button() - disables given GPIO button * @bdata: button data for button to be disabled * * Disables button pointed by @bdata. This is done by masking * IRQ line. After this function is called, button won't generate * input events anymore. Note that one can only disable buttons * that don't share IRQs. * * Make sure that @bdata->disable_lock is locked when entering * this function to avoid races when concurrent threads are * disabling buttons at the same time. */ static void gpio_keys_disable_button(struct gpio_button_data *bdata) { if (!bdata->disabled) { /* * Disable IRQ and associated timer/work structure. */ disable_irq(bdata->irq); if (bdata->gpiod) cancel_delayed_work_sync(&bdata->work); else del_timer_sync(&bdata->release_timer); bdata->disabled = true; } } /** * gpio_keys_enable_button() - enables given GPIO button * @bdata: button data for button to be disabled * * Enables given button pointed by @bdata. * * Make sure that @bdata->disable_lock is locked when entering * this function to avoid races with concurrent threads trying * to enable the same button at the same time. */ static void gpio_keys_enable_button(struct gpio_button_data *bdata) { if (bdata->disabled) { enable_irq(bdata->irq); bdata->disabled = false; } } /** * gpio_keys_attr_show_helper() - fill in stringified bitmap of buttons * @ddata: pointer to drvdata * @buf: buffer where stringified bitmap is written * @type: button type (%EV_KEY, %EV_SW) * @only_disabled: does caller want only those buttons that are * currently disabled or all buttons that can be * disabled * * This function writes buttons that can be disabled to @buf. If * @only_disabled is true, then @buf contains only those buttons * that are currently disabled. Returns 0 on success or negative * errno on failure. */ static ssize_t gpio_keys_attr_show_helper(struct gpio_keys_drvdata *ddata, char *buf, unsigned int type, bool only_disabled) { int n_events = get_n_events_by_type(type); unsigned long *bits; ssize_t ret; int i; bits = kcalloc(BITS_TO_LONGS(n_events), sizeof(*bits), GFP_KERNEL); if (!bits) return -ENOMEM; for (i = 0; i < ddata->pdata->nbuttons; i++) { struct gpio_button_data *bdata = &ddata->data[i]; if (bdata->button->type != type) continue; if (only_disabled && !bdata->disabled) continue; __set_bit(bdata->button->code, bits); } ret = scnprintf(buf, PAGE_SIZE - 1, "%*pbl", n_events, bits); buf[ret++] = '\n'; buf[ret] = '\0'; kfree(bits); return ret; } /** * gpio_keys_attr_store_helper() - enable/disable buttons based on given bitmap * @ddata: pointer to drvdata * @buf: buffer from userspace that contains stringified bitmap * @type: button type (%EV_KEY, %EV_SW) * * This function parses stringified bitmap from @buf and disables/enables * GPIO buttons accordingly. Returns 0 on success and negative error * on failure. */ static ssize_t gpio_keys_attr_store_helper(struct gpio_keys_drvdata *ddata, const char *buf, unsigned int type) { int n_events = get_n_events_by_type(type); const unsigned long *bitmap = get_bm_events_by_type(ddata->input, type); unsigned long *bits; ssize_t error; int i; bits = kcalloc(BITS_TO_LONGS(n_events), sizeof(*bits), GFP_KERNEL); if (!bits) return -ENOMEM; error = bitmap_parselist(buf, bits, n_events); if (error) goto out; /* First validate */ if (!bitmap_subset(bits, bitmap, n_events)) { error = -EINVAL; goto out; } for (i = 0; i < ddata->pdata->nbuttons; i++) { struct gpio_button_data *bdata = &ddata->data[i]; if (bdata->button->type != type) continue; if (test_bit(bdata->button->code, bits) && !bdata->button->can_disable) { error = -EINVAL; goto out; } } mutex_lock(&ddata->disable_lock); for (i = 0; i < ddata->pdata->nbuttons; i++) { struct gpio_button_data *bdata = &ddata->data[i]; if (bdata->button->type != type) continue; if (test_bit(bdata->button->code, bits)) gpio_keys_disable_button(bdata); else gpio_keys_enable_button(bdata); } mutex_unlock(&ddata->disable_lock); out: kfree(bits); return error; } #define ATTR_SHOW_FN(name, type, only_disabled) \ static ssize_t gpio_keys_show_##name(struct device *dev, \ struct device_attribute *attr, \ char *buf) \ { \ struct platform_device *pdev = to_platform_device(dev); \ struct gpio_keys_drvdata *ddata = platform_get_drvdata(pdev); \ \ return gpio_keys_attr_show_helper(ddata, buf, \ type, only_disabled); \ } ATTR_SHOW_FN(keys, EV_KEY, false); ATTR_SHOW_FN(switches, EV_SW, false); ATTR_SHOW_FN(disabled_keys, EV_KEY, true); ATTR_SHOW_FN(disabled_switches, EV_SW, true); /* * ATTRIBUTES: * * /sys/devices/platform/gpio-keys/keys [ro] * /sys/devices/platform/gpio-keys/switches [ro] */ static DEVICE_ATTR(keys, S_IRUGO, gpio_keys_show_keys, NULL); static DEVICE_ATTR(switches, S_IRUGO, gpio_keys_show_switches, NULL); #define ATTR_STORE_FN(name, type) \ static ssize_t gpio_keys_store_##name(struct device *dev, \ struct device_attribute *attr, \ const char *buf, \ size_t count) \ { \ struct platform_device *pdev = to_platform_device(dev); \ struct gpio_keys_drvdata *ddata = platform_get_drvdata(pdev); \ ssize_t error; \ \ error = gpio_keys_attr_store_helper(ddata, buf, type); \ if (error) \ return error; \ \ return count; \ } ATTR_STORE_FN(disabled_keys, EV_KEY); ATTR_STORE_FN(disabled_switches, EV_SW); /* * ATTRIBUTES: * * /sys/devices/platform/gpio-keys/disabled_keys [rw] * /sys/devices/platform/gpio-keys/disables_switches [rw] */ static DEVICE_ATTR(disabled_keys, S_IWUSR | S_IRUGO, gpio_keys_show_disabled_keys, gpio_keys_store_disabled_keys); static DEVICE_ATTR(disabled_switches, S_IWUSR | S_IRUGO, gpio_keys_show_disabled_switches, gpio_keys_store_disabled_switches); static struct attribute *gpio_keys_attrs[] = { &dev_attr_keys.attr, &dev_attr_switches.attr, &dev_attr_disabled_keys.attr, &dev_attr_disabled_switches.attr, NULL, }; static struct attribute_group gpio_keys_attr_group = { .attrs = gpio_keys_attrs, }; static void gpio_keys_gpio_report_event(struct gpio_button_data *bdata) { const struct gpio_keys_button *button = bdata->button; struct input_dev *input = bdata->input; unsigned int type = button->type ?: EV_KEY; int state; state = gpiod_get_value_cansleep(bdata->gpiod); if (state < 0) { dev_err(input->dev.parent, "failed to get gpio state: %d\n", state); return; } if (type == EV_ABS) { if (state) input_event(input, type, button->code, button->value); } else { input_event(input, type, button->code, state); } input_sync(input); } static void gpio_keys_gpio_work_func(struct work_struct *work) { struct gpio_button_data *bdata = container_of(work, struct gpio_button_data, work.work); gpio_keys_gpio_report_event(bdata); if (bdata->button->wakeup) pm_relax(bdata->input->dev.parent); } static irqreturn_t gpio_keys_gpio_isr(int irq, void *dev_id) { struct gpio_button_data *bdata = dev_id; BUG_ON(irq != bdata->irq); if (bdata->button->wakeup) pm_stay_awake(bdata->input->dev.parent); mod_delayed_work(system_wq, &bdata->work, msecs_to_jiffies(bdata->software_debounce)); return IRQ_HANDLED; } static void gpio_keys_irq_timer(unsigned long _data) { struct gpio_button_data *bdata = (struct gpio_button_data *)_data; struct input_dev *input = bdata->input; unsigned long flags; spin_lock_irqsave(&bdata->lock, flags); if (bdata->key_pressed) { input_event(input, EV_KEY, bdata->button->code, 0); input_sync(input); bdata->key_pressed = false; } spin_unlock_irqrestore(&bdata->lock, flags); } static irqreturn_t gpio_keys_irq_isr(int irq, void *dev_id) { struct gpio_button_data *bdata = dev_id; const struct gpio_keys_button *button = bdata->button; struct input_dev *input = bdata->input; unsigned long flags; BUG_ON(irq != bdata->irq); spin_lock_irqsave(&bdata->lock, flags); if (!bdata->key_pressed) { if (bdata->button->wakeup) pm_wakeup_event(bdata->input->dev.parent, 0); input_event(input, EV_KEY, button->code, 1); input_sync(input); if (!bdata->release_delay) { input_event(input, EV_KEY, button->code, 0); input_sync(input); goto out; } bdata->key_pressed = true; } if (bdata->release_delay) mod_timer(&bdata->release_timer, jiffies + msecs_to_jiffies(bdata->release_delay)); out: spin_unlock_irqrestore(&bdata->lock, flags); return IRQ_HANDLED; } static void gpio_keys_quiesce_key(void *data) { struct gpio_button_data *bdata = data; if (bdata->gpiod) cancel_delayed_work_sync(&bdata->work); else del_timer_sync(&bdata->release_timer); } static int gpio_keys_setup_key(struct platform_device *pdev, struct input_dev *input, struct gpio_button_data *bdata, const struct gpio_keys_button *button, struct fwnode_handle *child) { const char *desc = button->desc ? button->desc : "gpio_keys"; struct device *dev = &pdev->dev; irq_handler_t isr; unsigned long irqflags; int irq; int error; bdata->input = input; bdata->button = button; spin_lock_init(&bdata->lock); if (child) { bdata->gpiod = devm_get_gpiod_from_child(dev, NULL, child, GPIOD_IN, desc); if (IS_ERR(bdata->gpiod)) { error = PTR_ERR(bdata->gpiod); if (error == -ENOENT) { /* * GPIO is optional, we may be dealing with * purely interrupt-driven setup. */ bdata->gpiod = NULL; } else { if (error != -EPROBE_DEFER) dev_err(dev, "failed to get gpio: %d\n", error); return error; } } } else if (gpio_is_valid(button->gpio)) { /* * Legacy GPIO number, so request the GPIO here and * convert it to descriptor. */ unsigned flags = GPIOF_IN; if (button->active_low) flags |= GPIOF_ACTIVE_LOW; error = devm_gpio_request_one(&pdev->dev, button->gpio, flags, desc); if (error < 0) { dev_err(dev, "Failed to request GPIO %d, error %d\n", button->gpio, error); return error; } bdata->gpiod = gpio_to_desc(button->gpio); if (!bdata->gpiod) return -EINVAL; } if (bdata->gpiod) { if (button->debounce_interval) { error = gpiod_set_debounce(bdata->gpiod, button->debounce_interval * 1000); /* use timer if gpiolib doesn't provide debounce */ if (error < 0) bdata->software_debounce = button->debounce_interval; } if (button->irq) { bdata->irq = button->irq; } else { irq = gpiod_to_irq(bdata->gpiod); if (irq < 0) { error = irq; dev_err(dev, "Unable to get irq number for GPIO %d, error %d\n", button->gpio, error); return error; } bdata->irq = irq; } INIT_DELAYED_WORK(&bdata->work, gpio_keys_gpio_work_func); isr = gpio_keys_gpio_isr; irqflags = IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING; } else { if (!button->irq) { dev_err(dev, "Found button without gpio or irq\n"); return -EINVAL; } bdata->irq = button->irq; if (button->type && button->type != EV_KEY) { dev_err(dev, "Only EV_KEY allowed for IRQ buttons.\n"); return -EINVAL; } bdata->release_delay = button->debounce_interval; setup_timer(&bdata->release_timer, gpio_keys_irq_timer, (unsigned long)bdata); isr = gpio_keys_irq_isr; irqflags = 0; } input_set_capability(input, button->type ?: EV_KEY, button->code); /* * Install custom action to cancel release timer and * workqueue item. */ error = devm_add_action(&pdev->dev, gpio_keys_quiesce_key, bdata); if (error) { dev_err(&pdev->dev, "failed to register quiesce action, error: %d\n", error); return error; } /* * If platform has specified that the button can be disabled, * we don't want it to share the interrupt line. */ if (!button->can_disable) irqflags |= IRQF_SHARED; error = devm_request_any_context_irq(&pdev->dev, bdata->irq, isr, irqflags, desc, bdata); if (error < 0) { dev_err(dev, "Unable to claim irq %d; error %d\n", bdata->irq, error); return error; } return 0; } static void gpio_keys_report_state(struct gpio_keys_drvdata *ddata) { struct input_dev *input = ddata->input; int i; for (i = 0; i < ddata->pdata->nbuttons; i++) { struct gpio_button_data *bdata = &ddata->data[i]; if (bdata->gpiod) gpio_keys_gpio_report_event(bdata); } input_sync(input); } static int gpio_keys_open(struct input_dev *input) { struct gpio_keys_drvdata *ddata = input_get_drvdata(input); const struct gpio_keys_platform_data *pdata = ddata->pdata; int error; if (pdata->enable) { error = pdata->enable(input->dev.parent); if (error) return error; } /* Report current state of buttons that are connected to GPIOs */ gpio_keys_report_state(ddata); return 0; } static void gpio_keys_close(struct input_dev *input) { struct gpio_keys_drvdata *ddata = input_get_drvdata(input); const struct gpio_keys_platform_data *pdata = ddata->pdata; if (pdata->disable) pdata->disable(input->dev.parent); } /* * Handlers for alternative sources of platform_data */ /* * Translate properties into platform_data */ static struct gpio_keys_platform_data * gpio_keys_get_devtree_pdata(struct device *dev) { struct gpio_keys_platform_data *pdata; struct gpio_keys_button *button; struct fwnode_handle *child; int nbuttons; nbuttons = device_get_child_node_count(dev); if (nbuttons == 0) return ERR_PTR(-ENODEV); pdata = devm_kzalloc(dev, sizeof(*pdata) + nbuttons * sizeof(*button), GFP_KERNEL); if (!pdata) return ERR_PTR(-ENOMEM); button = (struct gpio_keys_button *)(pdata + 1); pdata->buttons = button; pdata->nbuttons = nbuttons; pdata->rep = device_property_read_bool(dev, "autorepeat"); device_property_read_string(dev, "label", &pdata->name); device_for_each_child_node(dev, child) { if (is_of_node(child)) button->irq = irq_of_parse_and_map(to_of_node(child), 0); if (fwnode_property_read_u32(child, "linux,code", &button->code)) { dev_err(dev, "Button without keycode\n"); fwnode_handle_put(child); return ERR_PTR(-EINVAL); } fwnode_property_read_string(child, "label", &button->desc); if (fwnode_property_read_u32(child, "linux,input-type", &button->type)) button->type = EV_KEY; button->wakeup = fwnode_property_read_bool(child, "wakeup-source") || /* legacy name */ fwnode_property_read_bool(child, "gpio-key,wakeup"); button->can_disable = fwnode_property_read_bool(child, "linux,can-disable"); if (fwnode_property_read_u32(child, "debounce-interval", &button->debounce_interval)) button->debounce_interval = 5; button++; } return pdata; } static const struct of_device_id gpio_keys_of_match[] = { { .compatible = "gpio-keys", }, { }, }; MODULE_DEVICE_TABLE(of, gpio_keys_of_match); static int gpio_keys_probe(struct platform_device *pdev) { struct device *dev = &pdev->dev; const struct gpio_keys_platform_data *pdata = dev_get_platdata(dev); struct fwnode_handle *child = NULL; struct gpio_keys_drvdata *ddata; struct input_dev *input; size_t size; int i, error; int wakeup = 0; if (!pdata) { pdata = gpio_keys_get_devtree_pdata(dev); if (IS_ERR(pdata)) return PTR_ERR(pdata); } size = sizeof(struct gpio_keys_drvdata) + pdata->nbuttons * sizeof(struct gpio_button_data); ddata = devm_kzalloc(dev, size, GFP_KERNEL); if (!ddata) { dev_err(dev, "failed to allocate state\n"); return -ENOMEM; } input = devm_input_allocate_device(dev); if (!input) { dev_err(dev, "failed to allocate input device\n"); return -ENOMEM; } ddata->pdata = pdata; ddata->input = input; mutex_init(&ddata->disable_lock); platform_set_drvdata(pdev, ddata); input_set_drvdata(input, ddata); input->name = pdata->name ? : pdev->name; input->phys = "gpio-keys/input0"; input->dev.parent = &pdev->dev; input->open = gpio_keys_open; input->close = gpio_keys_close; input->id.bustype = BUS_HOST; input->id.vendor = 0x0001; input->id.product = 0x0001; input->id.version = 0x0100; /* Enable auto repeat feature of Linux input subsystem */ if (pdata->rep) __set_bit(EV_REP, input->evbit); for (i = 0; i < pdata->nbuttons; i++) { const struct gpio_keys_button *button = &pdata->buttons[i]; struct gpio_button_data *bdata = &ddata->data[i]; if (!dev_get_platdata(dev)) { child = device_get_next_child_node(&pdev->dev, child); if (!child) { dev_err(&pdev->dev, "missing child device node for entry %d\n", i); return -EINVAL; } } error = gpio_keys_setup_key(pdev, input, bdata, button, child); if (error) { fwnode_handle_put(child); return error; } if (button->wakeup) wakeup = 1; } fwnode_handle_put(child); error = sysfs_create_group(&pdev->dev.kobj, &gpio_keys_attr_group); if (error) { dev_err(dev, "Unable to export keys/switches, error: %d\n", error); return error; } error = input_register_device(input); if (error) { dev_err(dev, "Unable to register input device, error: %d\n", error); goto err_remove_group; } device_init_wakeup(&pdev->dev, wakeup); return 0; err_remove_group: sysfs_remove_group(&pdev->dev.kobj, &gpio_keys_attr_group); return error; } static int gpio_keys_remove(struct platform_device *pdev) { sysfs_remove_group(&pdev->dev.kobj, &gpio_keys_attr_group); device_init_wakeup(&pdev->dev, 0); return 0; } static int __maybe_unused gpio_keys_suspend(struct device *dev) { struct gpio_keys_drvdata *ddata = dev_get_drvdata(dev); struct input_dev *input = ddata->input; int i; if (device_may_wakeup(dev)) { for (i = 0; i < ddata->pdata->nbuttons; i++) { struct gpio_button_data *bdata = &ddata->data[i]; if (bdata->button->wakeup) enable_irq_wake(bdata->irq); } } else { mutex_lock(&input->mutex); if (input->users) gpio_keys_close(input); mutex_unlock(&input->mutex); } return 0; } static int __maybe_unused gpio_keys_resume(struct device *dev) { struct gpio_keys_drvdata *ddata = dev_get_drvdata(dev); struct input_dev *input = ddata->input; int error = 0; int i; if (device_may_wakeup(dev)) { for (i = 0; i < ddata->pdata->nbuttons; i++) { struct gpio_button_data *bdata = &ddata->data[i]; if (bdata->button->wakeup) disable_irq_wake(bdata->irq); } } else { mutex_lock(&input->mutex); if (input->users) error = gpio_keys_open(input); mutex_unlock(&input->mutex); } if (error) return error; gpio_keys_report_state(ddata); return 0; } static SIMPLE_DEV_PM_OPS(gpio_keys_pm_ops, gpio_keys_suspend, gpio_keys_resume); static struct platform_driver gpio_keys_device_driver = { .probe = gpio_keys_probe, .remove = gpio_keys_remove, .driver = { .name = "gpio-keys", .pm = &gpio_keys_pm_ops, .of_match_table = gpio_keys_of_match, } }; static int __init gpio_keys_init(void) { return platform_driver_register(&gpio_keys_device_driver); } static void __exit gpio_keys_exit(void) { platform_driver_unregister(&gpio_keys_device_driver); } late_initcall(gpio_keys_init); module_exit(gpio_keys_exit); MODULE_LICENSE("GPL"); MODULE_AUTHOR("Phil Blundell "); MODULE_DESCRIPTION("Keyboard driver for GPIOs"); MODULE_ALIAS("platform:gpio-keys");