嵌入式Linux按键驱动，支持短按和长按检测

#include <linux/init.h> #include <linux/module.h> #include <linux/kernel.h> #include <linux/types.h> #include <linux/cdev.h> #include <linux/ide.h> #include <linux/of.h> #include <linux/platform_device.h> #include <linux/jiffies.h> #include <linux/signal.h> #include "chrdev_key.h" #include "imx6ull_key.h" static irqreturn_t imx6ull_key_interrupt(int irq, void *dev) { struct imx6ull_key_info *key_info = (struct imx6ull_key_info *)dev; //启动消抖定时器 mod_timer(&key_info->timer_press, jiffies + msecs_to_jiffies(KEY_STABLE_INTERVAL_MS)); return IRQ_HANDLED; } static void key_press_timer_func(unsigned long arg) { int level; struct imx6ull_key_info *key_info = (struct imx6ull_key_info *)arg; //读取按键状态 level = gpiod_get_value(key_info->desc); switch(key_info->pstatus) { case KEY_STATE_INITIAL: { if(level) key_info->pstatus = KEY_STATE_PRESSED; else key_info->pstatus = KEY_STATE_RELEASED; }break; case KEY_STATE_PRESSED: { if(!level) { key_info->pstatus = KEY_STATE_RELEASED; key_info->lpstatus = 0; //删除长按检测定时器 del_timer(&key_info->timer_lpress); } }break; case KEY_STATE_RELEASED: { if(level) { key_info->pstatus = KEY_STATE_PRESSED; key_info->pevents++; wake_up_interruptible(&key_info->key_waitqueue); kill_fasync(&key_info->key_async_queue, SIGIO, POLL_IN | POLLRDNORM); //启动长按检测定时器 mod_timer(&key_info->timer_lpress, jiffies + msecs_to_jiffies(KEY_LONG_PRESS_INTERVAL_MS)); } }break; default: break; } } static void key_long_press_timer_func(unsigned long arg) { struct imx6ull_key_info *key_info = (struct imx6ull_key_info *)arg; key_info->lpstatus = 1; wake_up_interruptible(&key_info->key_waitqueue); kill_fasync(&key_info->key_async_queue, SIGIO, POLL_IN | POLLRDNORM); } static int imx6ull_key_probe(struct platform_device *pdev) { int ret; struct imx6ull_key_info *key_info; if(!of_device_is_available(pdev->dev.of_node)) return -ENODEV; //申请内存用于存放KEY设备的资源 key_info = devm_kzalloc(&pdev->dev, sizeof(struct imx6ull_key_info), GFP_KERNEL); if(!key_info) { dev_err(&pdev->dev, "Failed to allocate memory for imx6ull key platform driver\n"); return -ENOMEM; } //将私有数据绑定到平台设备 platform_set_drvdata(pdev, key_info); //获取按键使用的引脚信息 key_info->desc = devm_gpiod_get(&pdev->dev, "key", GPIOD_ASIS); if(IS_ERR(key_info->desc)) { dev_err(&pdev->dev, "Failed to get GPIO pin for key\n"); return PTR_ERR(key_info->desc); } //获取按键引脚对应的中断信息 key_info->irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0); if(!key_info->irq) { dev_err(&pdev->dev, "no IRQ specified\n"); return -ENXIO; } //初始化等待队列头 init_waitqueue_head(&key_info->key_waitqueue); //初始化内核定时器 init_timer(&key_info->timer_press); key_info->timer_press.function = key_press_timer_func; key_info->timer_press.data = (unsigned long)key_info; init_timer(&key_info->timer_lpress); key_info->timer_lpress.function = key_long_press_timer_func; key_info->timer_lpress.data = (unsigned long)key_info; //获取按键使用的编号 ret = of_property_read_u32(pdev->dev.of_node, "id", &key_info->id); if(ret) return ret; //往内核注册一个LED字符设备 return key_chrdev_register(&key_info->key_cdev, key_info->id, 1, "imx6ull key"); } static int imx6ull_key_remove(struct platform_device *pdev) { struct imx6ull_key_info *key_info = platform_get_drvdata(pdev); return key_chrdev_unregister(&key_info->key_cdev, key_info->id, 1, "imx6ull key"); } static const struct of_device_id imx6ull_key_of_match[] = { { .compatible = "imx6ull-key" }, {} }; static struct platform_driver imx6ull_key_driver = { .probe = imx6ull_key_probe, .remove = imx6ull_key_remove, .driver = { .name = "imx6ull-key", .of_match_table = imx6ull_key_of_match, }, }; //------------------------------------------------------ static struct key_drv_func func_list; static int imx6ull_init_key_gpio(struct cdev *key_cdev, void **private) { int ret; struct imx6ull_key_info *key_info = container_of(key_cdev, struct imx6ull_key_info, key_cdev); //按键使用的引脚设置为输入 ret = gpiod_direction_input(key_info->desc); if(ret) return ret; //申请使用按键中断 ret = request_irq(key_info->irq->start, imx6ull_key_interrupt, key_info->irq->flags & IRQF_TRIGGER_MASK, "imx6ull key", key_info); if(ret) return ret; //初始化按键状态 key_info->pevents = 0; key_info->pstatus = KEY_STATE_INITIAL; key_info->lpstatus = KEY_STATE_INITIAL; //先触发一次按键定时器(为了同步按键的状态) add_timer(&key_info->timer_press); *private = key_info; return 0; } static int imx6ull_key_fasync(int fd, struct file *filp, int on) { struct imx6ull_key_info *key_info = (struct imx6ull_key_info *)filp->private_data; return fasync_helper(fd, filp, on, &key_info->key_async_queue); } static unsigned int imx6ull_poll_key_status(struct file *filp, poll_table *wait) { struct imx6ull_key_info *key_info = (struct imx6ull_key_info *)filp->private_data; poll_wait(filp, &key_info->key_waitqueue, wait); if(key_info->pevents || key_info->lpstatus) return POLLIN | POLLRDNORM; return 0; } static int imx6ull_read_key_status(struct file *filp, char *status) { char retval; struct imx6ull_key_info *key_info = (struct imx6ull_key_info *)filp->private_data; if((!key_info->pevents && !key_info->lpstatus)) { if(filp->f_flags & O_NONBLOCK) return -1; else wait_event_interruptible(key_info->key_waitqueue, (key_info->pevents || key_info->lpstatus)); } retval = 0; if(key_info->pevents) { retval |= (0x1 << 4); key_info->pevents--; } if(key_info->lpstatus) retval |= 0x1; *status = retval; return 0; } static int imx6ull_close_key_gpio(void *private) { struct imx6ull_key_info *key_info = (struct imx6ull_key_info *)private; free_irq(key_info->irq->start, key_info); del_timer_sync(&key_info->timer_press); del_timer_sync(&key_info->timer_lpress); return 0; } static int __init key_platform_driver_init(void) { func_list.func_init_key_gpio = imx6ull_init_key_gpio; func_list.func_key_fasync = imx6ull_key_fasync; func_list.func_poll_key_status = imx6ull_poll_key_status; func_list.func_read_key_status = imx6ull_read_key_status; func_list.func_close_key_gpio = imx6ull_close_key_gpio; key_chrdev_register_func(&func_list); return platform_driver_register(&imx6ull_key_driver); } static void __exit key_platform_driver_exit(void) { func_list.func_init_key_gpio = NULL; func_list.func_read_key_status = NULL; func_list.func_close_key_gpio = NULL; key_chrdev_unregister_func(); platform_driver_unregister(&imx6ull_key_driver); } module_init(key_platform_driver_init); module_exit(key_platform_driver_exit); //------------------------------------------------------- MODULE_LICENSE("GPL"); MODULE_AUTHOR("David.Tang");