Linux Platform Device and Driver,platform_add_devices()->platform_driver_register()

/* arch/arm/mach-s3c2410/devs.c */
/* I2C */
staticstruct resource s3c_i2c_resource[]={
[0]={
.start = S3C24XX_PA_IIC,
.end = S3C24XX_PA_IIC + S3C24XX_SZ_IIC -1,
.flags = IORESOURCE_MEM,
},
[1]={
.start = IRQ_IIC,//S3C2410_IRQ(27)
.end = IRQ_IIC,
.flags = IORESOURCE_IRQ,
}
};

struct platform_device s3c_device_i2c ={
.name ="s3c2410-i2c",
.id =-1,
.num_resources = ARRAY_SIZE(s3c_i2c_resource),
.resource = s3c_i2c_resource,
};

/* arch/arm/mach-3sc2410/cpu.c */
staticint __init s3c_arch_init(void)
{
int ret;
……
/* 这里board指针指向在mach-smdk2410.c里的定义的smdk2410_board，里面包含了预先定义的I2C Platform_device等. */
if(board !=NULL){
struct platform_device **ptr = board->devices;
int i;

for(i = 0; i < board->devices_count; i++, ptr++){
ret = platform_device_register(*ptr);    //在这里进行注册

if(ret){
printk(KERN_ERR "s3c24xx: failed to add board device %s (%d) @%p/n",(*ptr)->name,
ret,*ptr);
}
}
/* mask any error, we may not need all these board
* devices */
ret = 0;
}
return ret;
}

/* device driver for platform bus bits */

staticstruct platform_driver s3c2410_i2c_driver ={
.probe = s3c24xx_i2c_probe,
.remove= s3c24xx_i2c_remove,
.resume = s3c24xx_i2c_resume,
.driver ={
.owner = THIS_MODULE,
.name ="s3c2410-i2c",
},
};

/* drivers/i2c/busses/i2c-s3c2410.c */

staticint s3c24xx_i2c_probe(struct platform_device *pdev)
{
struct s3c24xx_i2c *i2c =&s3c24xx_i2c;
struct resource *res;
int ret;

/* find the clock and enable it */

i2c->dev =&pdev->dev;
i2c->clk = clk_get(&pdev->dev,"i2c");
if(IS_ERR(i2c->clk)){
dev_err(&pdev->dev,"cannot get clock/n");
ret =-ENOENT;
goto out;
}

dev_dbg(&pdev->dev,"clock source %p/n", i2c->clk);
clk_enable(i2c->clk);

/* map the registers */
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);/* 获取设备的IO资源地址 */
if(res ==NULL){
dev_err(&pdev->dev,"cannot find IO resource/n");
ret =-ENOENT;
goto out;
}

i2c->ioarea = request_mem_region(res->start,(res->end-res->start)+1, pdev->name);/* 申请这块IO Region */

if(i2c->ioarea ==NULL){
dev_err(&pdev->dev,"cannot request IO/n");
ret =-ENXIO;
goto out;
}

i2c->regs = ioremap(res->start,(res->end-res->start)+1);/* 映射至内核虚拟空间 */

if(i2c->regs ==NULL){
dev_err(&pdev->dev,"cannot map IO/n");
ret =-ENXIO;
goto out;
}

dev_dbg(&pdev->dev,"registers %p (%p, %p)/n", i2c->regs, i2c->ioarea, res);

/* setup info block for the i2c core */
i2c->adap.algo_data = i2c;
i2c->adap.dev.parent =&pdev->dev;

/* initialise the i2c controller */
ret = s3c24xx_i2c_init(i2c);
if(ret != 0)
goto out;

/* find the IRQ for this unit (note, this relies on the init call to ensure no current IRQs pending */

res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);/* 获取设备IRQ中断号 */

if(res ==NULL){
dev_err(&pdev->dev,"cannot find IRQ/n");
ret =-ENOENT;
goto out;
}

ret = request_irq(res->start, s3c24xx_i2c_irq, IRQF_DISABLED,/* 申请IRQ */
pdev->name, i2c);

……

return ret;

}