嵌入式Linux设备驱动开发之:GPIO驱动程序实例
staticintgpio_ioctl(structinode*inode,structfile*file,
unsignedintcmd,unsignedlongarg)
{/*ioctl函数接口:主要接口的实现。对5个GPIO设备进行控制(发亮或发声)*/
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操作函数,熄灭所有灯和关闭蜂鸣器*/
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)
{/*字符设备的创建和注册*/
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设备的file_operations结构定义*/
.owner=THIS_MODULE,
.open=gpio_open,/*进行初始化配置*/
.release=gpio_release,/*关闭设备*/
.read=gpio_read,
.write=gpio_write,
.ioctl=gpio_ioctl,/*实现主要控制功能*/
};
staticstructcdevgpio_devs;
staticintgpio_init(void)
{
intresult;
dev_tdev=MKDEV(major,0);
if(major)
{/*设备号的动态分配*/
result=register_chrdev_region(dev,1,GPIO_DEVICE_NAME);
}
else
{/*设备号的动态分配*/
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;
}
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