TQ2440LED驱动

这篇文档重在记述TQ2440的LED驱动，重点在于将LED作为混杂设备注册的方法

即 misc_register(&dev)和misc_deregister(®ister)

这篇文档所基于的环境如下

硬件环境：TQ2440开发板

kernel :linux 2.6.32

文件系统: busybox1.13.1，yaffs2

效果图如下

 

一、code

 

/*
name: leds driver for tq2660
author :keytounix
as char devices
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/poll.h>
#include <linux/timer.h>
#include <linux/irq.h>
#include <linux/cdev.h>
#include <linux/wait.h>//waitqueue

#include <linux/errno.h>
#include <linux/interrupt.h>//irq

#include <linux/io.h>
#include <linux/types.h>
#include <linux/delay.h>
#include <linux/semaphore.h>//sem

#include <linux/fs.h>
#include <linux/platform_device.h>//

#include <linux/miscdevice.h>

#include <linux/device.h>
#include <linux/workqueue.h>//workqueue


#include <asm/uaccess.h>
#include <asm/irq.h>

//soc相关


#include <mach/gpio.h>
#include <mach/regs-clock.h>
#include <mach/regs-gpio.h>
#include <mach/hardware.h>
#include <mach/irqs.h>


#define led_name "usr_leds"
#define LED_NAME "usr_leds"

//这个，是为了实现

//任何时刻只能有一个

//使用者能操作led

struct semaphore sem[4];
//打开

static int led_open0(struct inode *nodep,struct file * filep);
static int led_open1(struct inode *nodep,struct file * filep);
static int led_open2(struct inode *nodep,struct file * filep);
static int led_open3(struct inode *nodep,struct file * filep);
//关闭

static int led_release(struct inode *nodep,struct file * filep);
//ioctrl函数

static int led_ioctl(struct inode *nodep,struct file * filep,unsigned int cmd,long args);
//写数据

static int led_write(struct file * filep,char * __user buff,size_t count, loff_t *offt);
//这个函数用来实现对led的读写




static void led_display(int ledno,int status);

struct file_operations fops[]=
{
[0]={
.owner=THIS_MODULE,
.open=    led_open0,
.release=led_release,
.write =led_write,
.ioctl=led_ioctl,
},
[1]=
{
.owner=THIS_MODULE,
.open=led_open1,
.release=led_release,
.write =led_write,
.ioctl=led_ioctl,
},
[2]=
{
.owner=THIS_MODULE,
.open=led_open2,
.release=led_release,
.write =led_write,
.ioctl=led_ioctl,
},
[3]=
{
.owner=THIS_MODULE,
.open=led_open3,
.release=led_release,
.write =led_write,
.ioctl=led_ioctl,
},

};
struct LED_INFO
{
char * name;
unsigned pin;
}led_info[]=
{
[0]={
.name="led1",
.pin=S3C2410_GPB(5)
},
[1]={
.name="led2",
.pin=S3C2410_GPB(6)
},
[2]={
.name="led3",
.pin=S3C2410_GPB(7)
},
[3]={
.name="led4",
.pin=S3C2410_GPB(8)
}
};

static struct miscdevice led_dev[]=
{
[0]=
{
.minor =MISC_DYNAMIC_MINOR,
.name ="led0",
.fops =&fops[0]
},
[1]=
{
.minor =MISC_DYNAMIC_MINOR,
.name ="led1",
.fops=&fops[1]
},
[2]=
{
.minor=MISC_DYNAMIC_MINOR,
.name ="led2",
.fops =&fops[2]
},
[3]=
{
.minor=MISC_DYNAMIC_MINOR,
.name ="led3",
.fops=&fops[3]
}
};


#define LED_ON 0
#define LED_OFF 1
#define pin(x) led_info[x].pin


#define _DEBUG_ 1


#if _DEBUG_

#define debug(format,msg...) printk(format,##msg)

#else

#define debug(format,msg...) (void *)(0)

#endif
#define dbgi(name,i) debug("in %s ,%s is %d\n",__func__,name,i)

//打开函数，这个 函数里面我们需要获得sem

static int led_open0(struct inode * nodep,struct file *filep)
{
    down(&sem[0]);
    dbgi("filep->private_data",0);
    filep->private_data=0;
    return 0;
}
static int led_open1(struct inode * nodep,struct file *filep)
{
    down(&sem[1]);
    dbgi("filep->private_data",1);
    filep->private_data=1;
    return 0;
}
static int led_open2(struct inode * nodep,struct file *filep)
{
    down(&sem[2]);
    dbgi("filep->private_data",2);
    filep->private_data=2;
    return 0;
}
static int led_open3(struct inode * nodep,struct file *filep)
{
    down(&sem[3]);
    dbgi("filep->private_data",3);
    filep->private_data=3;
    return 0;
}

//关闭函数

static int led_release(struct inode *nodep,struct file *filep)
{
    int i=filep->private_data;
    dbgi("filep->private_data",i);
    i=(i<=3 && i>=0?i:0);
    up(&sem[i]);
    return 0;
}


//ioctrl函数

static int led_ioctl(struct inode * nodep,struct file *filep,unsigned int cmd ,long args)
{
    return 0;
}

static void led_display(int ledno,int status)
{
s3c2410_gpio_setpin(pin(ledno),status);
debug("in %s,ledno=%d,ledstatus=%d\n",__func__,ledno,status);
    return;
}
//

static int led_write(struct file * filep,char * __user buff,size_t count, loff_t *offt)
{
    int i=filep->private_data;

    char led_status[6];
    int cmd;
    dbgi("before i =(i<=3 && i>=0 ? i: 0),i=",i);
    i =(i<=3 && i>=0 ? i: 0);
    dbgi("after i =(i<=3 && i>=0 ? i: 0),i=",i);
    copy_from_user(led_status,buff,count);
    if(led_status[0]=='1' || led_status[0]==1)
        cmd=LED_ON;
    else
        cmd=LED_OFF;

        led_display(i,cmd);
    return 0;
}

////

static void __init led_init()
{

    int i=4;
       for(i=0;i<=3;i++)
       {
    misc_register(&led_dev[i]);
    init_MUTEX(&sem[i]);
    }
}
static void __exit led_exit()
{    int i=4;
    for(i=0;i<=3;i++)
    misc_deregister(&led_dev[i]);
}

MODULE_AUTHOR("keytounix");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("driver leds for TQ2440");
module_init(led_init);
module_exit(led_exit);

 

二、Makefile

 

TARGET=led

KERNEL=2.6.32

CC=arm-linux-gcc -w

obj-m :=$(TARGET).o

KERNELDIR :=/kernel/linux-$(KERNEL)



default:

make -C $(KERNELDIR) M=$(shell pwd) modules

 

三、test code

 

//arm-linux-gcc -marcharmv4t t.c -o t

//#insmod led.ko

//#mdev -s

//#./t /dev/ledx 1or0

#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <unistd.h>
int main(int argn,char*argv[])
{
int fd=open(argv[1],O_WRONLY,0640);
int w_size=write(fd,argv[2],sizeof(argv[2]));
close(fd);
return 0;
}