嵌入式Linux设备驱动开发之：GPIO驱动程序实例

设备号*/

voids3c2410_gpio_cfgpin(unsignedintpin,unsignedintfunction)

{/*对某个管脚进行配置（输入/输出/其他功能）*/

unsignedlongbase=S3C2410_GPIO_BASE(pin);/*获得端口的组基地址*/

unsignedlongshift=1;

unsignedlongmask=0x03;/*通常用配置寄存器的两位表示一个端口*/

unsignedlongcon;

unsignedlongflags;

if(pinS3C2410_GPIO_BANKB)

{

shift=0;

mask=0x01;/*在GPA端口中用配置寄存器的一位表示一个端口*/

}

mask=(S3C2410_GPIO_OFFSET(pin)shift);

local_irq_save(flags);/*保存现场，保证下面一段是原子操作*/

con=__raw_readl(base+0x00);

con=~mask;

con|=function;

__raw_writel(con,base+0x00);/*向配置寄存器写入新配置数据*/

local_irq_restore(flags);/*恢复现场*/

}

voids3c2410_gpio_pullup(unsignedintpin,unsignedintto)

{/*配置上拉功能*/

unsignedlongbase=S3C2410_GPIO_BASE(pin);/*获得端口的组基地址*/

unsignedlongoffs=S3C2410_GPIO_OFFSET(pin);/*获得端口的组内偏移地址*/

unsignedlongflags;

unsignedlongup;

if(pinS3C2410_GPIO_BANKB)

{

return;

}

local_irq_save(flags);

up=__raw_readl(base+0x08);

up=~(1offs);

up|=tooffs;

__raw_writel(up,base+0x08);/*向上拉功能寄存器写入新配置数据*/

local_irq_restore(flags);

}

voids3c2410_gpio_setpin(unsignedintpin,unsignedintto)

{/*向某个管脚进行输出*/

unsignedlongbase=S3C2410_GPIO_BASE(pin);

unsignedlongoffs=S3C2410_GPIO_OFFSET(pin);

unsignedlongflags;

unsignedlongdat;

local_irq_save(flags);

dat=__raw_readl(base+0x04);

dat=~(1offs);

dat|=tooffs;

__raw_writel(dat,base+0x04);/*向数据寄存器写入新数据*/

local_irq_restore(flags);

}

intgpio_open(structinode*inode,structfile*filp)

{/*open操作函数：进行寄存器配置*/

s3c2410_gpio_pullup(S3C2410_GPB0,1);/*BEEP*/

s3c2410_gpio_pullup(S3C2410_GPF4,1);/*LEDD12*/

s3c2410_gpio_pullup(S3C2410_GPF5,1);/*LEDD11*/

s3c2410_gpio_pullup(S3C2410_GPF6,1);/*LEDD10*/

s3c2410_gpio_pullup(S3C2410_GPF7,1);/*LEDD9*/

s3c2410_gpio_cfgpin(S3C2410_GPB0,S3C2410_GPB0_OUTP);

s3c2410_gpio_cfgpin(S3C2410_GPF4,S3C2410_GPF4_OUTP);

s3c2410_gpio_cfgpin(S3C2410_GPF4,S3C2410_GPF5_OUTP);

s3c2410_gpio_cfgpin(S3C2410_GPF4,S3C2410_GPF6_OUTP);

s3c2410_gpio_cfgpin(S3C2410_GPF4,S3C2410_GPF7_OUTP);

return0;

}

ssize_tgpio_read(structfile*file,char__user*buff,

size_tcount,loff_t*offp)

{/*read操作函数：没有实际功能*/

return0;

}

ssize_tgpio_write(structfile*file,constchar__user*buff,

size_tcount,loff_t*offp)

{/*write操作函数：没有实际功能*/

return0;

}

intswitch_gpio(unsignedintpin,unsignedintswt)

{/*向5个端口中的一个输出ON/OFF值*/

if(!((pin=S3C2410_GPF7)(pin>=S3C2410_GPF4))

(pin!=S3C2410_GPB0))

{

printk(Unsupportedpin);

return1;

}

s3c2410_gpio_setpin(pin,swt);

return0;

}

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(Unsupportedcommand\n);

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*/

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