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s
irqno1 = irq_of_parse_and_map(dev_irq, 0); //按键1索引号为0
if(!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;
}