嵌入式Linux之我行——LED驱动在2440上的实例开发

#gedit arch/arm/plat-s3c24xx/common-smdk.c //注释掉以下内容

staticstructplatform_device __initdata*smdk_devs[]={
&s3c_device_nand,

};

void__init smdk_machine_init(void)
{

if(machine_is_smdk2443())
smdk_nand_info.twrph0=50;

s3c_device_nand.dev.platform_data=&smdk_nand_info;

platform_add_devices(smdk_devs,ARRAY_SIZE(smdk_devs));

s3c_pm_init();
}

#include#include#include#include#include#include
#include

#defineDEVICE_NAME“my2440_leds”//设备称号
#defineLED_MAJOR231//主设备号
#defineLED_ON1//LED亮状况
#defineLED_OFF0//LED灭状况

staticunsignedlongled_table[]=//操控LED的IO口
{
S3C2410_GPB5,
S3C2410_GPB6,
S3C2410_GPB7,
S3C2410_GPB8,
};

staticunsignedintled_cfg_table[]=//LED IO口的形式
{
S3C2410_GPB5_OUTP,
S3C2410_GPB6_OUTP,
S3C2410_GPB7_OUTP,
S3C2410_GPB8_OUTP,
};

staticintleds_open(structinode*inode,structfile*file)
{
return0;
}

staticintleds_ioctl(structinode*inode,structfile*file,
unsignedintcmd,unsignedlongarg)
{
//检测是第几个LED，因开发板上只要4个，索引从0开端
if(arg<0||arg>3)
{
return-EINVAL;
}

//判别LED要碑文哪种状况
switch(cmd)
{
caseLED_ON:
{
s3c2410_gpio_setpin(led_table[arg],~(LED_ON));
break;
}
caseLED_OFF:
{
s3c2410_gpio_setpin(led_table[arg],~(LED_OFF));
break;
}
default:
{
return-EINVAL;
}
}

return0;
}

staticstructfile_operations leds_fops=
{
.owner=THIS_MODULE,
.open=leds_open,
.ioctl=leds_ioctl,
};

staticint__init led_init(void)
{
intret,i;

for(i=0;i<4;i++)
{
//初始化各IO口为输出形式
s3c2410_gpio_cfgpin(led_table[i],led_cfg_table[i]);

//由原理图可知LED电路是共阳极的(即各IO口输出低电平0才会点亮)
//这儿初始化为1，不让LED点亮
s3c2410_gpio_setpin(led_table[i],~(LED_OFF));
}

//注册LED设备为字符设备
ret=register_chrdev(LED_MAJOR,DEVICE_NAME,&leds_fops);

if(ret<0)
{
printk(DEVICE_NAME” register falid!\n”);
returnret;
}
}

staticvoid__exit led_exit(void)
{
//刊出设备
unregister_chrdev(LED_MAJOR,DEVICE_NAME);
}

module_init(led_init);
module_exit(led_exit);

MODULE_L%&&&&&%ENSE(“GPL”);
MODULE_AUTHOR(“Huang Gang”);
MODULE_DESCRIPTION(“My2440 led driver”);

#cp -f my2440_leds.c /linux-2.6.30.4/drivers/char //把驱动源码复制到内核驱动的字符设备下

#gedit /linux-2.6.30.4/drivers/char/Kconfig //增加LED设备装备

config MY2440_LEDS
tristate “My2440 Leds Device”
depends on ARCH_S3C2440
default y
—help—
My2440 User Leds

#gedit /linux-2.6.30.4/drivers/char/Makefile //增加LED设备装备

obj-$(CONFIG_MY2440_LEDS)+= my2440_leds.o

#make menuconfig

Device Drivers —>
Character devices —>
<*>My2440 Leds Device (NEW)

#include
#include
#include
#include

intmain(intargc,char**argv)
{
intturn,index,fd;

//检测输入的参数合法性
if(argc!=3||sscanf(argv[2],“%d”,&index)!=1||index<1||index>4)
{
printf(“Usage: leds_test on|off 1|2|3|4\n”);
exit(1);
}

if(strcmp(argv[1],“on”)==0)
{
turn=1;
}
elseif(strcmp(argv[1],“off”)==0)
{
turn=0;
}
else
{
printf(“Usage: leds_test on|off 1|2|3|4\n”);
exit(1);
}

//翻开LED设备
fd=open(“/dev/my2440_leds”,0);

if(fd<0)
{
printf(“Open Led Device Faild!\n”);
exit(1);
}

//IO操控
ioctl(fd,turn,index–1);

//封闭LED设备
close(fd);

return0;
}

#arm-linux-gcc -o leds_test leds_test.c