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

/* arch/arm/mach-s3c2410/devs.c */
/* I2C */
static struct 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 */
static int __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 */

static
struct 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 */

static int 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;

    
}