【Linux 驱动】简单字符设备驱动架构(LED驱动)

本文基于icool210开发板，内核版本：linux2.6.35；

驱动代码：

(1)头文件:led.h

 #ifndef __LED_H__
 #define __LED_H__

 #define LED_MAGIC 'l'
 #define LED_1_ON    _IO(LED_MAGIC, 0)
 #define LED_1_OFF   _IO(LED_MAGIC, 1)
 #define LED_2_ON    _IO(LED_MAGIC, 3)
 #define LED_2_OFF   _IO(LED_MAGIC, 4)
 #define LED_3_ON    _IO(LED_MAGIC, 5)
 #define LED_3_OFF   _IO(LED_MAGIC, 6)
 #define LED_4_ON    _IO(LED_MAGIC, 7)
 #define LED_4_OFF   _IO(LED_MAGIC, 8)
 #define LED_5_ON    _IO(LED_MAGIC, 9)
 #define LED_5_OFF   _IO(LED_MAGIC, 10)
 #define LED_6_ON    _IO(LED_MAGIC, 11)
 #define LED_6_OFF   _IO(LED_MAGIC, 12)

 #endif

(2)代码文件：led.c

 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/cdev.h>
 #include <linux/fs.h>
 #include <linux/io.h>
 #include "led.h"

 #define GPBCON  0xE0200040
 #define GPBDAT  0xE0200044
 #define GPH0CON 0xE0200C00
 #define GPH0DAT 0xE0200C04
 unsigned int *led_gpb_config;
 unsigned int *led_gpb_data;
 unsigned int *led_gph0_config;
 unsigned int *led_gph0_data;

 struct cdev led_dev;
 dev_t devno;

 /****************************************************************************
 ** 函数名: led_open
 ** 功  能: led设备驱动的操作函数集的open函数
 ** 参  数: struct inode *pstInode
 **         struct file *pstFile
 ** 日  期: 2017年2月22日
 ** 作  者: Rookie
 *****************************************************************************/
 int led_open(struct inode *pstInode, struct file *pstFile)
 {
     unsigned int uiDataTemp;

     /*
     ** 配置LED对应的GPIO为Output
     ** LED1 -- GPB0   LED2 -- GPIO2
     ** LED3 -- GPB1   LED4 -- GPIO4
     */
     led_gpb_config = ioremap(GPBCON, );
     uiDataTemp = readl(led_gpb_config);
     uiDataTemp &= 0xFFFF0000;
     uiDataTemp |= 0x1111;
     writel(uiDataTemp, led_gpb_config);

     /* LED5 -- GPH0_7   LED6 -- GPH0_5 */
     led_gph0_config = ioremap(GPH0CON, );
     uiDataTemp = readl(led_gph0_config);
     uiDataTemp &= 0xF0FFFFF;
     uiDataTemp |= 0x10100000;
     writel(uiDataTemp, led_gph0_config);

     led_gpb_data = ioremap(GPBDAT, );
     led_gph0_data = ioremap(GPH0DAT, );

     return ;
 }

 /****************************************************************************
 ** 函数名: led_ioctl
 ** 功  能: led设备驱动的操作函数集的ioctl函数
 ** 参  数: struct file *pstFile
 **         unsigned int uiCmd
 **         unsigned long ulArgc
 ** 日  期: 2017年2月22日
 ** 作  者: Rookie
 *****************************************************************************/
 long led_ioctl(struct file *pstFile, unsigned int uiCmd, unsigned long ulArgc)
 {
     unsigned int uiDataTemp;

     switch (uiCmd)
     {
         case (LED_1_ON):
             uiDataTemp = readl(led_gpb_data);
             uiDataTemp |= 0x1;
             writel(uiDataTemp, led_gpb_data);
             printk("led1--on\r\n");
             break;

         case (LED_1_OFF):
             uiDataTemp = readl(led_gpb_data);
             uiDataTemp &= 0xFFFFFFFE;
             writel(uiDataTemp, led_gpb_data);
             printk("led1--off\r\n");
             break;

         case (LED_2_ON):
             uiDataTemp = readl(led_gpb_data);
             uiDataTemp |= 0x4;
             writel(uiDataTemp, led_gpb_data);
             printk("led2--on\r\n");
             break;

         case (LED_2_OFF):
             uiDataTemp = readl(led_gpb_data);
             uiDataTemp &= 0xFFFFFFFB;
             writel(uiDataTemp, led_gpb_data);
             printk("led2--off\r\n");
             break;

         case (LED_3_ON):
             uiDataTemp = readl(led_gpb_data);
             uiDataTemp |= 0x2;
             writel(uiDataTemp, led_gpb_data);
             break;

         case (LED_3_OFF):
             uiDataTemp = readl(led_gpb_data);
             uiDataTemp &= 0xFFFFFFFD;
             writel(uiDataTemp, led_gpb_data);
             break;

         case (LED_4_ON):
             uiDataTemp = readl(led_gpb_data);
             uiDataTemp |= 0x8;
             writel(uiDataTemp, led_gpb_data);
             break;

         case (LED_4_OFF):
             uiDataTemp = readl(led_gpb_data);
             uiDataTemp &= 0xFFFFFFF7;
             writel(uiDataTemp, led_gpb_data);
             break;

         case (LED_5_ON):
             uiDataTemp = readl(led_gph0_data);
             uiDataTemp |= 0x80;
             writel(uiDataTemp, led_gph0_data);
             break;

         case (LED_5_OFF):
             uiDataTemp = readl(led_gph0_data);
             uiDataTemp &= 0xFFFFFF7F;
             writel(uiDataTemp, led_gph0_data);
             break;

         case (LED_6_ON):
             uiDataTemp = readl(led_gph0_data);
             uiDataTemp |= 0x20;
             writel(uiDataTemp, led_gph0_data);
             break;

         case (LED_6_OFF):
             uiDataTemp = readl(led_gph0_data);
             uiDataTemp &= 0xFFFFFFDF;
             writel(uiDataTemp, led_gph0_data);
             break;

         default:
             return -EINVAL;
     }

     return ;
 }

 static struct file_operations led_ops =
 {
     .open = led_open,
     .unlocked_ioctl = led_ioctl,
 };

 /****************************************************************************
 ** 函数名: led_init
 ** 功  能: led设备驱动初始化函数
 ** 参  数: void
 ** 日  期: 2017年2月22日
 ** 作  者: Rookie
 *****************************************************************************/
 static int __init led_init(void)
 {
     cdev_init(&led_dev, &led_ops);

     alloc_chrdev_region(&devno, , , "my_led");
     cdev_add(&led_dev, devno, );

     return ;
 }

 /****************************************************************************
 ** 函数名: led_exit
 ** 功  能: led设备驱动退出函数
 ** 参  数: void
 ** 日  期: 2017年2月22日
 ** 作  者: Rookie
 *****************************************************************************/
 static void __exit led_exit(void)
 {
     cdev_del(&led_dev);
     unregister_chrdev_region(devno, );

     return;
 }

 module_init(led_init);
 module_exit(led_exit);
 MODULE_LICENSE("GPL");

(3)Makefile文件

 obj-m := led.o
 KDIR := /root/wksp/icool210/linux2.6.35-icool210-v1.
 all:
     make -C $(KDIR) M=$(PWD) modules CROSS_COMPILE=arm-linux- ARCH=arm
 clean:
     rm -rf *.ko *.o *.order *symvers

(4)测试应用程序:app.c

 #include <stdio.h>
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <fcntl.h>
 #include <sys/ioctl.h>
 #include "led.h"

 int main(int argc, const char *argv[])
 {
     int iFd;
     int iLedNum;
     int iLedStatus;

     if (argc < )
     {
         printf("Please Enter 3 Para!\r\n");
         return -;
     }

     iLedNum = atoi(argv[]);
     iLedStatus = atoi(argv[]);

     iFd = open("/dev/my_led", O_RDWR);

     if ( == iLedNum)
     {
         if ( == iLedStatus)
         {
             ioctl( iFd, LED_1_ON);
         }
         else
         {
             ioctl( iFd, LED_1_OFF);
         }
     }
     else if ( == iLedNum)
     {
         if ( == iLedStatus)
         {
             ioctl( iFd, LED_2_ON);
         }
         else
         {
             ioctl( iFd, LED_2_OFF);
         }
     }
     else if ( == iLedNum)
     {
         if ( == iLedStatus)
         {
             ioctl( iFd, LED_3_ON);
         }
         else
         {
             ioctl( iFd, LED_3_OFF);
         }
     }
     else if ( == iLedNum)
     {
         if ( == iLedStatus)
         {
             ioctl( iFd, LED_4_ON);
         }
         else
         {
             ioctl( iFd, LED_4_OFF);
         }
     }
     else if ( == iLedNum)
     {
         if ( == iLedStatus)
         {
             ioctl( iFd, LED_5_ON);
         }
         else
         {
             ioctl( iFd, LED_5_OFF);
         }
     }
     else if ( == iLedNum)
     {
         if ( == iLedStatus)
         {
             ioctl( iFd, LED_6_ON);
         }
         else
         {
             ioctl( iFd, LED_6_OFF);
         }
     }

     return ;
 }

操作方法：

(1)编译 .ko 文件

在驱动代码路径直接执行 make

(2)编译 应用程序

arm-linux-gcc -static app.c -o app

(3)记载内核模块

insmod led.ko

(4)创建设备节点

mknod /dev/my_led c 251 0

(5) 执行应用程序

./app 1 1