驱动层

#include <linux/init.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_irq.h>
#include <linux/interrupt.h>
#include <linux/fs.h>
#include <linux/gpio.h>
#include <linux/of_gpio.h>#define LED_ON  _IO('l', 1)
#define LED_OFF _IO('l', 0)struct class *cls;
struct device *dev;
struct device_node *dev_irq, *dev_led;
unsigned int major;
unsigned int irqno1, irqno2, irqno3;
struct gpio_desc *gpiono1, *gpiono2, *gpiono3;//中断处理函数
irqreturn_t myirq_handler(int irq, void *dev)
{if(irq == irqno1) {gpiod_set_value(gpiono1, !gpiod_get_value(gpiono1));}else if(irq == irqno2) {gpiod_set_value(gpiono2, !gpiod_get_value(gpiono2));}else if(irq == irqno3) {gpiod_set_value(gpiono3, !gpiod_get_value(gpiono3));}return IRQ_HANDLED;
}int mycdev_open(struct inode *inode, struct file *file)
{int a = inode->i_rdev;  //获取当前设备文件对应的设备号file->private_data = (void *)MINOR(a);  //将次设备号保存到当前文件的file结构中return 0;
}long mycdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{unsigned int a = (unsigned int)file->private_data;switch(a){case 0:switch(cmd){case LED_ON:gpiod_set_value(gpiono1, 1);break;case LED_OFF:gpiod_set_value(gpiono1, 0);break;}break;   case 1:switch(cmd){case LED_ON:gpiod_set_value(gpiono2, 1);break;case LED_OFF:gpiod_set_value(gpiono2, 0);break;}break; case 2:switch(cmd){case LED_ON:gpiod_set_value(gpiono3, 1);break;case LED_OFF:gpiod_set_value(gpiono3, 0);break;}break;                          }return 0;
}struct file_operations fops = {.open = mycdev_open,.unlocked_ioctl = mycdev_ioctl,
};static int __init mycdev_init(void)
{// 注册字符设备驱动major = register_chrdev(0, "mychrdev", &fops);if (major < 0){printk("注册字符设备驱动失败\n");return major;}printk("注册字符设备驱动成功major=%d\n", major);// 向上提交目录cls = class_create(THIS_MODULE, "myled");if (IS_ERR(cls)){printk("向上提交目录失败\n");return -PTR_ERR(cls);}printk("向上提交目录信息成功\n");// 向上提交设备节点信息int i;for (i = 0; i < 3; i++){dev = device_create(cls, NULL, MKDEV(major, i), NULL, "myled%d", i);if (IS_ERR(dev)){printk("向上提交设备节点信息失败\n");return -PTR_ERR(dev);}}printk("向上提交设备节点成功\n");int ret;//解析设备树节点dev_irq = of_find_node_by_path("/myirq");if(dev_irq == NULL){printk("解析irq设备树节点失败\n");return -EFAULT;}dev_led = of_find_node_by_path("/leds");if(dev_led == NULL){printk("解析led设备树节点失败\n");return -EIO;}printk("解析设备树节点成功\n");// 申请gpio_desc对象并设置输出为低电平gpiono1 = gpiod_get_from_of_node(dev_led, "led1-gpios", 0, GPIOD_OUT_LOW, NULL);if(IS_ERR(gpiono1)){printk("申请gpio对象失败\n");return -PTR_ERR(gpiono1);}gpiono2 = gpiod_get_from_of_node(dev_led, "led2-gpios", 0, GPIOD_OUT_LOW, NULL);if(IS_ERR(gpiono1)){printk("申请gpio对象失败\n");return -PTR_ERR(gpiono1);}gpiono3 = gpiod_get_from_of_node(dev_led, "led3-gpios", 0, GPIOD_OUT_LOW, NULL);if(IS_ERR(gpiono1)){printk("申请gpio对象失败\n");return -PTR_ERR(gpiono1);}printk("申请gpio对象成功\n");//根据设备树节点解析出软中断号sirqno1 = irq_of_parse_and_map(dev_irq, 0); //按键1索引号为0if(!irqno1){printk("解析软中断号失败\n");return -ENXIO;}irqno2 = irq_of_parse_and_map(dev_irq, 1);if(!irqno2){printk("解析软中断号失败\n");return -ENXIO;}irqno3 = irq_of_parse_and_map(dev_irq, 2);if(!irqno3){printk("解析软中断号失败\n");return -ENXIO;}printk("解析软中断号成功 irqno123=%d,%d,%d\n",irqno1,irqno2,irqno3);//注册中断ret = request_irq(irqno1, myirq_handler, IRQF_TRIGGER_FALLING, "key1", NULL);if(ret){printk("注册中断失败\n");return ret;}ret = request_irq(irqno2, myirq_handler, IRQF_TRIGGER_FALLING, "key2", NULL);if(ret){printk("注册中断失败\n");return ret;}ret = request_irq(irqno3, myirq_handler, IRQF_TRIGGER_FALLING, "key3", NULL);if(ret){printk("注册中断失败\n");return ret;}printk("注册中断成功\n");return 0;
}static void __exit mycdev_exit(void)
{//注销中断free_irq(irqno1, NULL);free_irq(irqno2, NULL);free_irq(irqno3, NULL);//灭灯gpiod_set_value(gpiono1, 0);gpiod_set_value(gpiono2, 0);gpiod_set_value(gpiono3, 0);//释放gpio编号gpiod_put(gpiono1);gpiod_put(gpiono2);gpiod_put(gpiono3);//销毁节点信息int i;for (i = 0; i < 3; i++){device_destroy(cls, MKDEV(major, i));}//销毁目录信息class_destroy(cls);//注销字符设备驱动unregister_chrdev(major, "mycdev");
}module_init(mycdev_init);
module_exit(mycdev_exit);
MODULE_LICENSE("GPL");

应用层 

#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <fcntl.h>
#include <unistd.h>
#include <string.h>
#include <stdlib.h>#define LED_ON  _IO('l', 1)
#define LED_OFF _IO('l', 0)int main(int argc,const char * argv[])
{int sel;int fd1 = open("/dev/myled0", O_RDWR);if(fd1 < 0){perror("open");printf("%s : %s : %d\n", __FILE__, __func__, __LINE__);return -1;}int fd2 = open("/dev/myled1", O_RDWR);if(fd2 < 0){perror("open");printf("%s : %s : %d\n", __FILE__, __func__, __LINE__);return -1;}int fd3 = open("/dev/myled2", O_RDWR);if(fd3 < 0){perror("open");printf("%s : %s : %d\n", __FILE__, __func__, __LINE__);return -1;}while(1){printf("1> LED1 ON\n");printf("2> LED1 OFF\n");printf("3> LED2 ON\n");printf("4> LED2 OFF\n");printf("5> LED3 ON\n");printf("6> LED3 OFF\n");printf("请选择功能>>>");scanf("%d", &sel);getchar();switch(sel){case 1:ioctl(fd1, LED_ON); break;case 2:ioctl(fd1, LED_OFF);break;case 3:ioctl(fd2, LED_ON); break;case 4:ioctl(fd2, LED_OFF);break;case 5:ioctl(fd3, LED_ON); break;case 6:ioctl(fd3, LED_OFF);break;}}close(fd1);close(fd2);close(fd3);return 0;
}