嵌入式Linux之我行——LED驅動在2440上的實例開發

#gedit arch/arm/plat-s3c24xx/common-smdk.c //注釋掉以下內容

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"//設備名稱
#defineLED_MAJOR231//主設備號
#defineLED_ON1//LED亮狀態
#defineLED_OFF0//LED滅狀態

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

staticunsignedintled_cfg_table[]=//LED IO口的模式
{
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)
{
//檢測是第幾個LED，因開發板上只有4個，索引從0開始
if(arg<0||arg>3)
{
return-EINVAL;
}

//判斷LED要執行哪種狀態
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口為輸出模式
s3c2410_gpio_cfgpin(led_table[i],led_cfg_table[i]);

//由原理圖可知LED電路是共陽極的(即各IO口輸出低電平0才會點亮)
//這里初始化為1，不讓LED點亮
s3c2410_gpio_setpin(led_table[i],~(LED_OFF));
}

//注冊LED設備為字符設備
ret=register_chrdev(LED_MAJOR,DEVICE_NAME,&leds_fops);

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

staticvoid__exit led_exit(void)
{
//注銷設備
unregister_chrdev(LED_MAJOR,DEVICE_NAME);
}

module_init(led_init);
module_exit(led_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Huang Gang");
MODULE_DESCRIPTION("My2440 led driver");

#cp -f my2440_leds.c /linux-2.6.30.4/drivers/char //把驅動源碼復制到內核驅動的字符設備下

#gedit /linux-2.6.30.4/drivers/char/Kconfig //添加LED設備配置

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 //添加LED設備配置

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;

//檢測輸入的參數合法性
if(argc!=3||sscanf(argv[2],"%d",&index)!=1||index<1||index>4)
{
printf("Usage: leds_test on|off 1|2|3|4n");
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|4n");
exit(1);
}

//打開LED設備
fd=open("/dev/my2440_leds",0);

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

//IO控制
ioctl(fd,turn,index-1);

//關閉LED設備
close(fd);

return0;
}

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