树莓派按键驱动和用户侧程序

#include <linux/module.h> #include <linux/poll.h> #include <linux/fs.h> #include <linux/errno.h> #include <linux/miscdevice.h> #include <linux/kernel.h> #include <linux/major.h> #include <linux/mutex.h> #include <linux/proc_fs.h> #include <linux/seq_file.h> #include <linux/stat.h> #include <linux/init.h> #include <linux/device.h> #include <linux/tty.h> #include <linux/kmod.h> #include <linux/gfp.h> #include <linux/gpio/consumer.h> #include <linux/platform_device.h> #include <linux/of_gpio.h> #include <linux/of_irq.h> #include <linux/interrupt.h> #include <linux/irq.h> #include <linux/slab.h> #include <linux/fcntl.h> #include <linux/timer.h> #include <linux/workqueue.h> #include <asm/current.h> /* 主设备号 */ static int major = 0; static struct class *gpio_button_class; static struct gpio_desc *button_handle; static int gpio_num; static int button_irq; static int g_button_value = 0; static DECLARE_WAIT_QUEUE_HEAD(gpio_key_wait); struct fasync_struct *button_fasync; /* 实现对应的open/read/write等函数，填入file_operations结构体 */ static ssize_t gpio_button_drv_read (struct file *file, char __user *buf, size_t size, loff_t *offset) { printk("%s %s line %d\n", __FILE__, __FUNCTION__, __LINE__); //printk("%s %s line %d\n", __FILE__, __FUNCTION__, __LINE__); int err; wait_event_interruptible(gpio_key_wait, g_button_value); err = copy_to_user(buf, &g_button_value, 4); g_button_value = 0; return 4; } static unsigned int gpio_button_drv_poll(struct file *fp, poll_table * wait) { printk("%s %s line %d\n", __FILE__, __FUNCTION__, __LINE__); poll_wait(fp, &gpio_key_wait, wait); if(g_button_value) return POLLIN | POLLRDNORM; else return 0; } static int gpio_button_drv_fasync(int fd, struct file *file, int on) { printk("%s %s line %d\n", __FILE__, __FUNCTION__, __LINE__); if (fasync_helper(fd, file, on, &button_fasync) >= 0) return 0; else return -EIO; } /* 定义自己的file_operations结构体 */ static struct file_operations gpio_button_drv = { .owner = THIS_MODULE, .read = gpio_button_drv_read, .poll = gpio_button_drv_poll, .fasync = gpio_button_drv_fasync, }; static irqreturn_t gpio_button_isr(int irq, void *dev_id) { int val; val = gpiod_get_value(button_handle); printk("key value %d\n", val); if(val) { g_button_value = val; wake_up_interruptible(&gpio_key_wait); kill_fasync(&button_fasync, SIGIO, POLL_IN); } return IRQ_HANDLED; } /* 1. 从platform_device获得GPIO * 2. gpio=>irq * 3. request_irq */ static int gpio_button_probe(struct platform_device *pdev) { printk("%s %s line %d\n", __FILE__, __FUNCTION__, __LINE__); button_handle = gpiod_get(&pdev->dev, NULL, 0); gpiod_direction_input(button_handle); #if 0 struct device_node *node = pdev->dev.of_node; enum of_gpio_flags flag; gpio_num = of_get_gpio_flags(node, 0, &flag); button_irq = gpio_to_irq(gpio_num); #else button_irq = gpiod_to_irq(button_handle); #endif request_irq(button_irq, gpio_button_isr, IRQF_TRIGGER_RISING, "pgg_button_irq", NULL);//IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING /* 注册file_operations */ major = register_chrdev(0, "pgg_button", &gpio_button_drv); /* /dev/gpio_key */ gpio_button_class = class_create(THIS_MODULE, "gpio_button_class"); if (IS_ERR(gpio_button_class)) { printk("%s %s line %d\n", __FILE__, __FUNCTION__, __LINE__); unregister_chrdev(major, "pgg_button"); return PTR_ERR(gpio_button_class); } device_create(gpio_button_class, NULL, MKDEV(major, 0), NULL, "pgg_button"); /* /dev/100ask_gpio_key */ return 0; } static int gpio_button_remove(struct platform_device *pdev) { printk("%s %s line %d\n", __FILE__, __FUNCTION__, __LINE__); device_destroy(gpio_button_class, MKDEV(major, 0)); class_destroy(gpio_button_class); unregister_chrdev(major, "pgg_button"); gpiod_put(button_handle); free_irq(button_irq,NULL); return 0; } static const struct of_device_id pgg_button[] = { { .compatible = "pgg,button" }, { }, }; /* 1. 定义platform_driver */ static struct platform_driver gpio_button_driver = { .probe = gpio_button_probe, .remove = gpio_button_remove, .driver = { .name = "pgg_gpio_button", .of_match_table = pgg_button, }, }; /* 2. 在入口函数注册platform_driver */ static int __init gpio_button_init(void) { int err; printk("%s %s line %d\n", __FILE__, __FUNCTION__, __LINE__); err = platform_driver_register(&gpio_button_driver); return err; } /* 3. 有入口函数就应该有出口函数：卸载驱动程序时，就会去调用这个出口函数 * 卸载platform_driver */ static void __exit gpio_button_exit(void) { printk("%s %s line %d\n", __FILE__, __FUNCTION__, __LINE__); platform_driver_unregister(&gpio_button_driver); } /* 7. 其他完善：提供设备信息，自动创建设备节点 */ module_init(gpio_button_init); module_exit(gpio_button_exit); MODULE_LICENSE("GPL");