写一个linux led灯驱动
时间: 2024-02-21 11:01:05 浏览: 18
以下是一个简单的 Linux LED 灯驱动程序示例,适用于基于 ARM 架构的嵌入式 Linux 系统:
```c
#include <linux/module.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/cdev.h>
#include <linux/io.h>
#include <linux/uaccess.h>
#define LED_MAJOR 200
#define LED_MINOR 0
#define LED_NUM 1
#define LED_NAME "led"
#define GPIO_BASE 0x01c20800
#define GPIO_SIZE 0x00001000
#define LED_OFF 0
#define LED_ON 1
static void __iomem *gpio_base;
struct led_dev {
dev_t devno;
struct cdev cdev;
};
static struct led_dev led;
static int led_open(struct inode *inode, struct file *filp)
{
return 0;
}
static int led_release(struct inode *inode, struct file *filp)
{
return 0;
}
static ssize_t led_write(struct file *filp, const char __user *buf, size_t count, loff_t *f_pos)
{
unsigned char led_state;
int ret;
ret = copy_from_user(&led_state, buf, 1);
if (ret < 0) {
return -EFAULT;
}
if (led_state == LED_ON) {
iowrite32((1 << 0), gpio_base);
} else {
iowrite32(0, gpio_base);
}
return 1;
}
static const struct file_operations led_fops = {
.owner = THIS_MODULE,
.open = led_open,
.release = led_release,
.write = led_write,
};
static int __init led_init(void)
{
int ret;
led.devno = MKDEV(LED_MAJOR, LED_MINOR);
ret = register_chrdev_region(led.devno, LED_NUM, LED_NAME);
if (ret < 0) {
printk(KERN_ERR "Failed to register char device region\n");
return ret;
}
cdev_init(&led.cdev, &led_fops);
led.cdev.owner = THIS_MODULE;
ret = cdev_add(&led.cdev, led.devno, LED_NUM);
if (ret < 0) {
printk(KERN_ERR "Failed to add char device\n");
unregister_chrdev_region(led.devno, LED_NUM);
return ret;
}
gpio_base = ioremap(GPIO_BASE, GPIO_SIZE);
if (!gpio_base) {
printk(KERN_ERR "Failed to map GPIO memory\n");
cdev_del(&led.cdev);
unregister_chrdev_region(led.devno, LED_NUM);
return -ENOMEM;
}
iowrite32(0x00000000, gpio_base + 0x00);
iowrite32(0x00000000, gpio_base + 0x04);
iowrite32(0x00000000, gpio_base + 0x08);
iowrite32(0x00000000, gpio_base + 0x0c);
iowrite32(0x00000000, gpio_base + 0x10);
iowrite32(0x00000000, gpio_base + 0x14);
iowrite32(0x00000000, gpio_base + 0x18);
iowrite32(0x00000000, gpio_base + 0x1c);
return 0;
}
static void __exit led_exit(void)
{
iounmap(gpio_base);
cdev_del(&led.cdev);
unregister_chrdev_region(led.devno, LED_NUM);
}
module_init(led_init);
module_exit(led_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Your Name");
MODULE_DESCRIPTION("Linux LED Driver");
```
这个驱动程序使用了一个 GPIO 控制一个 LED 灯的开关状态,LED 灯连接在开发板的某个 IO 引脚上。用户可以通过 write 系统调用向驱动程序发送控制命令,打开或关闭 LED 灯。