作業(yè)：通過字符設備驅(qū)動分步注冊方式編寫LED驅(qū)動，完成設備文件和設備的綁定
驅(qū)動程序：myled.c
#include <linux/init.h>
#include <linux/module.h>
#include <linux/cdev.h>
#include <linux/fs.h>
#include <linux/device.h>
#include <linux/uaccess.h>
#include <linux/slab.h>
#include <linux/io.h>
#include "head.h"
char kbuf[128] = "";
struct cdev *cdev;
unsigned int major = 0;
unsigned int minor = 0;
dev_t devno;
module_param(major, uint, 0664); //方便命令行傳遞major的值
struct class *cls;
struct device *dev;
gpio_t *vir_led1;
gpio_t *vir_led2;
gpio_t *vir_led3;
unsigned int *vir_rcc;
//封裝操作方法
int mycdev_open(struct inode *inode, struct file *file)
{
int min = MINOR(inode->i_rdev); //根據(jù)打開的文件對應的設備號獲取次設備號
file->private_data = (void *)min;
printk("%s:%s:%d\n", __FILE__, __func__, __LINE__);
return 0;
}
long mycdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
int min = (int)file->private_data; //傳遞次設備號
//設備文件和設備的綁定，根據(jù)次設備號決定打開的設備文件，根據(jù)打開的設備文件，控制相應的設備
switch (min)
{
case 0: //控制LED1
switch (cmd)
{
case LED_ON: //開燈
vir_led1->ODR |= (0x1 << 10);
break;
case LED_OFF: //關燈
vir_led1->ODR &= (~(0x1 << 10));
break;
}
break;
case 1: //控制LED2
switch (cmd)
{
case LED_ON: //開燈
vir_led2->ODR |= (0x1 << 10);
break;
case LED_OFF: //關燈
vir_led2->ODR &= (~(0x1 << 10));
break;
}
break;
case 2: //控制LED3
switch (cmd)
{
case LED_ON: //開燈
vir_led3->ODR |= (0x1 << 8);
break;
case LED_OFF: //關燈
vir_led3->ODR &= (~(0x1 << 8));
break;
}
break;
}
return 0;
}
ssize_t mycdev_read(struct file *file, char *ubuf, size_t size, loff_t *lof)
{
return 0;
}
ssize_t mycdev_write(struct file *file, const char *ubuf, size_t size, loff_t *lof)
{
return 0;
}
int mycdev_close(struct inode *inode, struct file *file)
{
printk("%s:%s:%d\n", __FILE__, __func__, __LINE__);
return 0;
}
//定義一個操作方法結(jié)構(gòu)體對象并初始化
struct file_operations fops = {
.open = mycdev_open,
.unlocked_ioctl = mycdev_ioctl,
.read = mycdev_read,
.write = mycdev_write,
.release = mycdev_close,
};
int all_led_init(void)
{
//進行相關寄存器的內(nèi)存映射
//GPIOE組寄存器內(nèi)存映射
vir_led1 = ioremap(PHY_LED1_ADDR, sizeof(gpio_t));
if (vir_led1 == NULL)
{
printk("物理內(nèi)存映射失敗%d\n", __LINE__);
return -EFAULT;
}
vir_led2 = ioremap(PHY_LED2_ADDR, sizeof(gpio_t));
if (vir_led2 == NULL)
{
printk("物理內(nèi)存映射失敗%d\n", __LINE__);
return -EFAULT;
}
vir_led3 = vir_led1;
vir_rcc = ioremap(PHY_RCC_ADDR, 4);
if (vir_rcc == NULL)
{
printk("物理內(nèi)存映射失敗%d\n", __LINE__);
return -EFAULT;
}
printk("寄存器內(nèi)存映射成功\n");
//硬件寄存器的初始化
//RCC使能
(*vir_rcc) |= (0x3 << 4); //GPIOE(PE10 PE8)使能 GPIOF(PF10)使能
//設置PE10為輸出模式 --> LED1
(vir_led1->MODER) &= (~(0x3 << 20));
(vir_led1->MODER) |= (0x1 << 20);
//設置PF10為輸出模式 --> LED2
(vir_led2->MODER) &= (~(0x3 << 20));
(vir_led2->MODER) |= (0x1 << 20);
//設置PE8為輸出模式 --> LED3
(vir_led3->MODER) &= (~(0x3 << 16));
(vir_led3->MODER) |= (0x1 << 16);
//默認LED1關燈
(vir_led1->ODR) &= (~(0x1 << 10));
//默認LED2關燈
(vir_led2->ODR) &= (~(0x1 << 10));
//默認LED1關燈
(vir_led3->ODR) &= (~(0x1 << 8));
printk("寄存器初始化成功\n");
return 0;
}
static int __init mycdev_init(void)
{
//寄存器內(nèi)存地址映射以及初始化
all_led_init();
int ret;
//1.為字符設備驅(qū)動對象申請空間
cdev = cdev_alloc();
if (cdev == NULL)
{
printk("申請字符設備驅(qū)動對象空間失敗\n");
ret = -EFAULT;
goto out1;
}
printk("申請字符設備驅(qū)動對象空間成功\n");
//2.初始化字符設備驅(qū)動對象
cdev_init(cdev, &fops);
printk("初始化字符設備驅(qū)動對象成功\n");
//3.申請設備號
if (major > 0) //靜態(tài)指定設備號
{
ret = register_chrdev_region(MKDEV(major, minor), 3, "myled");
if (ret)
{
printk("靜態(tài)申請設備號失敗\n");
goto out2;
}
}
else if (major == 0)
{ //動態(tài)申請設備號
ret = alloc_chrdev_region(&devno, minor, 3, "myled");
if (ret)
{
printk("動態(tài)申請設備號失敗\n");
goto out2;
}
major = MAJOR(devno); //獲取主設備號
minor = MINOR(devno); //獲取次設備號
}
printk("申請設備號成功 major= %d\n", major);
//4.注冊字符設備驅(qū)動對象
ret = cdev_add(cdev, MKDEV(major, minor), 3);
if (ret)
{
printk("注冊字符設備驅(qū)動對象失敗\n");
goto out3;
}
printk("注冊字符設備驅(qū)動對象成功\n");
//向上提交目錄信息
cls = class_create(THIS_MODULE, "myled");
if (IS_ERR(cls))
{
printk("向上提交目錄失敗\n");
ret = -PTR_ERR(cls);
goto out4;
}
printk("向上提交目錄成功\n");
//向上提交設備節(jié)點信息
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("向上提交設備節(jié)點信息失敗\n");
ret = -PTR_ERR(dev);
goto out5;
}
}
printk("向上提交設備信息成功\n");
return 0;
out5:
//釋放前一次提交成功的設備信息
for (--i; i >= 0; i--)
{
device_destroy(cls, MKDEV(major, i));
}
class_destroy(cls); //釋放目錄
out4:
//注銷字符設備驅(qū)動對象
cdev_del(cdev);
out3:
//釋放設備號
unregister_chrdev_region(MKDEV(major, minor), 3);
out2:
//釋放設備驅(qū)動對象空間
kfree(cdev);
out1:
return ret;
}
static void __exit mycdev_exit(void)
{
int i;
//釋放設備節(jié)點信息
for (i = 0; i < 0; i++)
{
device_destroy(cls, MKDEV(major, i));
}
//銷毀目錄
class_destroy(cls);
//注銷字符設備驅(qū)動對象
cdev_del(cdev);
//釋放設備號
unregister_chrdev_region(MKDEV(major, minor), 3);
//釋放設備驅(qū)動對象空間
kfree(cdev);
}
module_init(mycdev_init);
module_exit(mycdev_exit);
MODULE_LICENSE("GPL");應用程序：test.c
#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>
#include "head.h"
int main()
{
int a, b;
char buf[128] = "";
int fd1, fd2, fd3;
while (1)
{
printf("請輸入要控制的燈：0(LED1) 1(LED2) 2(LED3) >");
scanf("%d", &a);
switch (a)
{
case 0:
fd1 = open("/dev/myled0", O_RDWR);
if (fd1 < 0)
{
printf("設備文件打開失敗\n");
exit(-1);
}
printf("請輸入對LED的控制命令：0(關燈) 1(開燈) >");
scanf("%d", &b);
switch (b)
{
case 0:
ioctl(fd1, LED_OFF); //關燈
close(fd1);
break;
case 1:
ioctl(fd1, LED_ON); //開燈
close(fd1);
break;
}
break;
case 1:
fd2 = open("/dev/myled1", O_RDWR);
if (fd2 < 0)
{
printf("設備文件打開失敗\n");
exit(-1);
}
printf("請輸入對LED的控制命令：0(關燈) 1(開燈) >");
scanf("%d", &b);
switch (b)
{
case 0:
ioctl(fd2, LED_OFF); //關燈
close(fd2);
break;
case 1:
ioctl(fd2, LED_ON); //開燈
close(fd2);
break;
}
break;
case 2:
fd3 = open("/dev/myled2", O_RDWR);
if (fd3 < 0)
{
printf("設備文件打開失敗\n");
exit(-1);
}
printf("請輸入對LED的控制命令：0(關燈) 1(開燈) >");
scanf("%d", &b);
switch (b)
{
case 0:
ioctl(fd3, LED_OFF); //關燈
close(fd3);
break;
case 1:
ioctl(fd3, LED_ON); //開燈
close(fd3);
break;
}
break;
}
}
close(fd1);
close(fd2);
close(fd3);
return 0;
}
頭文件：head.h
#ifndef __HEAD_H__
#define __HEAD_H__
typedef struct{
unsigned int MODER;
unsigned int OTYPER;
unsigned int OSPEEDR;
unsigned int PUPDR;
unsigned int IDR;
unsigned int ODR;
}gpio_t;
#define PHY_LED1_ADDR 0x50006000
#define PHY_LED2_ADDR 0x50007000
#define PHY_LED3_ADDR 0x50006000
#define PHY_RCC_ADDR 0x50000A28
//構(gòu)建LED開關的功能碼，不添加ioctl第三個參數(shù)
#define LED_ON _IO('l', 1)
#define LED_OFF _IO('l', 0)
#endif
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