/* * Driver for keys on GPIO lines capable of generating interrupts. * * Copyright 2005 Phil Blundell * Copyright 2010, 2011 David Jander <david@protonic.nl> * * 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 <linux/module.h> #include <linux/init.h> #include <linux/fs.h> #include <linux/interrupt.h> #include <linux/irq.h> #include <linux/sched.h> #include <linux/pm.h> #include <linux/slab.h> #include <linux/sysctl.h> #include <linux/proc_fs.h> #include <linux/delay.h> #include <linux/platform_device.h> #include <linux/input.h> #include <linux/gpio_keys.h> #include <linux/workqueue.h> #include <linux/gpio.h> #include <linux/of_platform.h> #include <linux/of_gpio.h> struct gpio_button_data { struct gpio_keys_button *button; struct input_dev *input; struct timer_list timer; struct work_struct work; int timer_debounce; /* in msecs */ bool disabled; }; struct gpio_keys_drvdata { struct input_dev *input; struct mutex disable_lock; unsigned int n_buttons; int (*enable)(struct device *dev); void (*disable)(struct device *dev); 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 inline int get_n_events_by_type(int type) { BUG_ON(type != EV_SW && type != EV_KEY); return (type == EV_KEY) ? KEY_CNT : SW_CNT; } /** * 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 possible debouncing timer. */ disable_irq(gpio_to_irq(bdata->button->gpio)); if (bdata->timer_debounce) del_timer_sync(&bdata->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(gpio_to_irq(bdata->button->gpio)); 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->n_buttons; 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 = bitmap_scnlistprintf(buf, PAGE_SIZE - 2, bits, n_events); 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 accordinly. 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); 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 */ for (i = 0; i < ddata->n_buttons; 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->n_buttons; 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_report_event(struct gpio_button_data *bdata) { struct gpio_keys_button *button = bdata->button; struct input_dev *input = bdata->input; unsigned int type = button->type ?: EV_KEY; int state = (gpio_get_value_cansleep(button->gpio) ? 1 : 0) ^ button->active_low; 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_work_func(struct work_struct *work) { struct gpio_button_data *bdata = container_of(work, struct gpio_button_data, work); gpio_keys_report_event(bdata); } static void gpio_keys_timer(unsigned long _data) { struct gpio_button_data *data = (struct gpio_button_data *)_data; schedule_work(&data->work); } static irqreturn_t gpio_keys_isr(int irq, void *dev_id) { struct gpio_button_data *bdata = dev_id; struct gpio_keys_button *button = bdata->button; BUG_ON(irq != gpio_to_irq(button->gpio)); if (bdata->timer_debounce) mod_timer(&bdata->timer, jiffies + msecs_to_jiffies(bdata->timer_debounce)); else schedule_work(&bdata->work); return IRQ_HANDLED; } static int __devinit gpio_keys_setup_key(struct platform_device *pdev, struct gpio_button_data *bdata, struct gpio_keys_button *button) { const char *desc = button->desc ? button->desc : "gpio_keys"; struct device *dev = &pdev->dev; unsigned long irqflags; int irq, error; setup_timer(&bdata->timer, gpio_keys_timer, (unsigned long)bdata); INIT_WORK(&bdata->work, gpio_keys_work_func); error = gpio_request(button->gpio, desc); if (error < 0) { dev_err(dev, "failed to request GPIO %d, error %d\n", button->gpio, error); goto fail2; } error = gpio_direction_input(button->gpio); if (error < 0) { dev_err(dev, "failed to configure" " direction for GPIO %d, error %d\n", button->gpio, error); goto fail3; } if (button->debounce_interval) { error = gpio_set_debounce(button->gpio, button->debounce_interval * 1000); /* use timer if gpiolib doesn't provide debounce */ if (error < 0) bdata->timer_debounce = button->debounce_interval; } irq = gpio_to_irq(button->gpio); if (irq < 0) { error = irq; dev_err(dev, "Unable to get irq number for GPIO %d, error %d\n", button->gpio, error); goto fail3; } irqflags = IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING; /* * 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 = request_threaded_irq(irq, NULL, gpio_keys_isr, irqflags, desc, bdata); if (error < 0) { dev_err(dev, "Unable to claim irq %d; error %d\n", irq, error); goto fail3; } return 0; fail3: gpio_free(button->gpio); fail2: return error; } static int gpio_keys_open(struct input_dev *input) { struct gpio_keys_drvdata *ddata = input_get_drvdata(input); return ddata->enable ? ddata->enable(input->dev.parent) : 0; } static void gpio_keys_close(struct input_dev *input) { struct gpio_keys_drvdata *ddata = input_get_drvdata(input); if (ddata->disable) ddata->disable(input->dev.parent); } /* * Handlers for alternative sources of platform_data */ #ifdef CONFIG_OF /* * Translate OpenFirmware node properties into platform_data */ static int gpio_keys_get_devtree_pdata(struct device *dev, struct gpio_keys_platform_data *pdata) { struct device_node *node, *pp; int i; struct gpio_keys_button *buttons; u32 reg; node = dev->of_node; if (node == NULL) return -ENODEV; memset(pdata, 0, sizeof *pdata); pdata->rep = !!of_get_property(node, "autorepeat", NULL); /* First count the subnodes */ pdata->nbuttons = 0; pp = NULL; while ((pp = of_get_next_child(node, pp))) pdata->nbuttons++; if (pdata->nbuttons == 0) return -ENODEV; buttons = kzalloc(pdata->nbuttons * (sizeof *buttons), GFP_KERNEL); if (!buttons) return -ENOMEM; pp = NULL; i = 0; while ((pp = of_get_next_child(node, pp))) { enum of_gpio_flags flags; if (!of_find_property(pp, "gpios", NULL)) { pdata->nbuttons--; dev_warn(dev, "Found button without gpios\n"); continue; } buttons[i].gpio = of_get_gpio_flags(pp, 0, &flags); buttons[i].active_low = flags & OF_GPIO_ACTIVE_LOW; if (of_property_read_u32(pp, "linux,code", ®)) { dev_err(dev, "Button without keycode: 0x%x\n", buttons[i].gpio); goto out_fail; } buttons[i].code = reg; buttons[i].desc = of_get_property(pp, "label", NULL); if (of_property_read_u32(pp, "linux,input-type", ®) == 0) buttons[i].type = reg; else buttons[i].type = EV_KEY; buttons[i].wakeup = !!of_get_property(pp, "gpio-key,wakeup", NULL); if (of_property_read_u32(pp, "debounce-interval", ®) == 0) buttons[i].debounce_interval = reg; else buttons[i].debounce_interval = 5; i++; } pdata->buttons = buttons; return 0; out_fail: kfree(buttons); return -ENODEV; } static struct of_device_id gpio_keys_of_match[] = { { .compatible = "gpio-keys", }, { }, }; MODULE_DEVICE_TABLE(of, gpio_keys_of_match); #else static int gpio_keys_get_devtree_pdata(struct device *dev, struct gpio_keys_platform_data *altp) { return -ENODEV; } #define gpio_keys_of_match NULL #endif static int __devinit gpio_keys_probe(struct platform_device *pdev) { struct gpio_keys_platform_data *pdata = pdev->dev.platform_data; struct gpio_keys_drvdata *ddata; struct device *dev = &pdev->dev; struct gpio_keys_platform_data alt_pdata; struct input_dev *input; int i, error; int wakeup = 0; if (!pdata) { error = gpio_keys_get_devtree_pdata(dev, &alt_pdata); if (error) return error; pdata = &alt_pdata; } ddata = kzalloc(sizeof(struct gpio_keys_drvdata) + pdata->nbuttons * sizeof(struct gpio_button_data), GFP_KERNEL); input = input_allocate_device(); if (!ddata || !input) { dev_err(dev, "failed to allocate state\n"); error = -ENOMEM; goto fail1; } ddata->input = input; ddata->n_buttons = pdata->nbuttons; ddata->enable = pdata->enable; ddata->disable = pdata->disable; 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++) { struct gpio_keys_button *button = &pdata->buttons[i]; struct gpio_button_data *bdata = &ddata->data[i]; unsigned int type = button->type ?: EV_KEY; bdata->input = input; bdata->button = button; error = gpio_keys_setup_key(pdev, bdata, button); if (error) goto fail2; if (button->wakeup) wakeup = 1; input_set_capability(input, type, button->code); } 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); goto fail2; } error = input_register_device(input); if (error) { dev_err(dev, "Unable to register input device, error: %d\n", error); goto fail3; } /* get current state of buttons */ for (i = 0; i < pdata->nbuttons; i++) gpio_keys_report_event(&ddata->data[i]); input_sync(input); device_init_wakeup(&pdev->dev, wakeup); return 0; fail3: sysfs_remove_group(&pdev->dev.kobj, &gpio_keys_attr_group); fail2: while (--i >= 0) { free_irq(gpio_to_irq(pdata->buttons[i].gpio), &ddata->data[i]); if (ddata->data[i].timer_debounce) del_timer_sync(&ddata->data[i].timer); cancel_work_sync(&ddata->data[i].work); gpio_free(pdata->buttons[i].gpio); } platform_set_drvdata(pdev, NULL); fail1: input_free_device(input); kfree(ddata); /* If we have no platform_data, we allocated buttons dynamically. */ if (!pdev->dev.platform_data) kfree(pdata->buttons); return error; } static int __devexit gpio_keys_remove(struct platform_device *pdev) { struct gpio_keys_drvdata *ddata = platform_get_drvdata(pdev); struct input_dev *input = ddata->input; int i; sysfs_remove_group(&pdev->dev.kobj, &gpio_keys_attr_group); device_init_wakeup(&pdev->dev, 0); for (i = 0; i < ddata->n_buttons; i++) { int irq = gpio_to_irq(ddata->data[i].button->gpio); free_irq(irq, &ddata->data[i]); if (ddata->data[i].timer_debounce) del_timer_sync(&ddata->data[i].timer); cancel_work_sync(&ddata->data[i].work); gpio_free(ddata->data[i].button->gpio); } input_unregister_device(input); /* * If we had no platform_data, we allocated buttons dynamically, and * must free them here. ddata->data[0].button is the pointer to the * beginning of the allocated array. */ if (!pdev->dev.platform_data) kfree(ddata->data[0].button); kfree(ddata); return 0; } #ifdef CONFIG_PM_SLEEP static int gpio_keys_suspend(struct device *dev) { struct gpio_keys_drvdata *ddata = dev_get_drvdata(dev); int i; if (device_may_wakeup(dev)) { for (i = 0; i < ddata->n_buttons; i++) { struct gpio_keys_button *button = ddata->data[i].button; if (button->wakeup) { int irq = gpio_to_irq(button->gpio); enable_irq_wake(irq); } } } return 0; } static int gpio_keys_resume(struct device *dev) { struct gpio_keys_drvdata *ddata = dev_get_drvdata(dev); int i; for (i = 0; i < ddata->n_buttons; i++) { struct gpio_keys_button *button = ddata->data[i].button; if (button->wakeup && device_may_wakeup(dev)) { int irq = gpio_to_irq(button->gpio); disable_irq_wake(irq); } gpio_keys_report_event(&ddata->data[i]); } input_sync(ddata->input); return 0; } #endif 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 = __devexit_p(gpio_keys_remove), .driver = { .name = "gpio-keys", .owner = THIS_MODULE, .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 <pb@handhelds.org>"); MODULE_DESCRIPTION("Keyboard driver for GPIOs"); MODULE_ALIAS("platform:gpio-keys");