嵌入式Linux設備驅動開發之：GPIO驅動程序實例

staticintgpio_ioctl(structinode*inode,structfile*file,

unsignedintcmd,unsignedlongarg)

{/*ioctl函數接口:主要接口的實現。對5個GPIO設備進行控制（發亮或發聲）*/

unsignedintswt=(unsignedint)arg;

switch(cmd)

{

caseLED_D09_SWT:

{

switch_gpio(S3C2410_GPF7,swt);

}

break;

caseLED_D10_SWT:

{

switch_gpio(S3C2410_GPF6,swt);

}

break;

caseLED_D11_SWT:

{

switch_gpio(S3C2410_GPF5,swt);

}

break;

caseLED_D12_SWT:

{

switch_gpio(S3C2410_GPF4,swt);

}

break;

caseBEEP_SWT:

{

switch_gpio(S3C2410_GPB0,swt);

break;

}

default:

{

printk(Unsupportedcommandn);

break;

}

}

return0;

}

staticintgpio_release(structinode*node,structfile*file)

{/*release操作函數，熄滅所有燈和關閉蜂鳴器*/

switch_gpio(S3C2410_GPB0,BEEP_SWT_OFF);

switch_gpio(S3C2410_GPF4,LED_SWT_OFF);

switch_gpio(S3C2410_GPF5,LED_SWT_OFF);

switch_gpio(S3C2410_GPF6,LED_SWT_OFF);

switch_gpio(S3C2410_GPF7,LED_SWT_OFF);

return0;

}

staticvoidgpio_setup_cdev(structcdev*dev,intminor,

structfile_operations*fops)

{/*字符設備的創建和注冊*/

interr,devno=MKDEV(major,minor);

cdev_init(dev,fops);

dev->owner=THIS_MODULE;

dev->ops=fops;

err=cdev_add(dev,devno,1);

if(err)

{

printk(KERN_NOTICEError%daddinggpio%d,err,minor);

}

}

staticstructfile_operationsgpio_fops=

{/*gpio設備的file_operations結構定義*/

.owner=THIS_MODULE,

.open=gpio_open,/*進行初始化配置*/

.release=gpio_release,/*關閉設備*/

.read=gpio_read,

.write=gpio_write,

.ioctl=gpio_ioctl,/*實現主要控制功能*/

};

staticstructcdevgpio_devs;

staticintgpio_init(void)

{

intresult;

dev_tdev=MKDEV(major,0);

if(major)

{/*設備號的動態分配*/

result=register_chrdev_region(dev,1,GPIO_DEVICE_NAME);

}

else

{/*設備號的動態分配*/

result=alloc_chrdev_region(dev,0,1,GPIO_DEVICE_NAME);

major=MAJOR(dev);

}

if(result0)

{

printk(KERN_WARNINGGpio:unabletogetmajor%dn,major);

returnresult;

}

gpio_setup_cdev(gpio_devs,0,gpio_fops);

printk(Themajorofthegpiodeviceis%dn,major);

return0;

}