linux SDIO实现

在Linu 2.6.21的SDIO驱动，它是除了是mmc_host的驱动外，还是一个Platform驱动.身兼两职.

在这个版本中，首先是定义三个platform_deivce 以注册到系统当中。但是它定义在

  arch/arm/plat-s3c24xx/devs.c (这会让人感当相当迷惑),它创建是 s3c-hsmmc设备

 

struct platform_device s3c_device_hsmmc0 = {                         .name             = "s3c-hsmmc",                             .id               = 0,                                       .num_resources    = ARRAY_SIZE(s3c_hsmmc0_resource),         .resource         = s3c_hsmmc0_resource,                     .dev            = {                                                  .platform_data = &s3c_hsmmc0_platform,               }                                                    };                                                                                                                                                                                     struct platform_device s3c_device_hsmmc1 = {                         .name             = "s3c-hsmmc",                             .id               = 1,                                       .num_resources    = ARRAY_SIZE(s3c_hsmmc1_resource),         .resource         = s3c_hsmmc1_resource,                     .dev            = {                                                  .platform_data = &s3c_hsmmc1_platform,               }                                                    };

 

  其platform_driver 定义在drivers/mmc/s3c-hsmmc.c

 

static struct platform_driver s3c_hsmmc_driver =             {                                                                    .probe          = s3c_hsmmc_probe,                           .remove         = s3c_hsmmc_remove,                          .suspend        = s3c_hsmmc_suspend,                         .resume         = s3c_hsmmc_resume,                          .driver         = {                                                  .name   = "s3c-hsmmc",                                       .owner  = THIS_MODULE,                               },                                                   };                                                                                                                        static int __init s3c_hsmmc_drv_init(void)                   {                                                                    return platform_driver_register(&s3c_hsmmc_driver);  }                                                                                                                         static void __exit s3c_hsmmc_drv_exit(void)                  {                                                                    platform_driver_unregister(&s3c_hsmmc_driver);       }

 

在s3c_hsmmc_probe函数中，会进行一系列的初始化操作.

 

Linux 2.6.28的SDIO的实现

  Linux 2.6.28又做了进一步调整，原来的s3c-hsmmc的设备和驱动已经放弃，原来在s3c-hsmmc.c 已经成为残余代码，虽然在内核中，但是不会加入Makefile编译。

其新的platform_device 定义分布定义在 dev-hsmmc.c /dev-hsmmc1.c / dev-hsmmc2.c,可以看到设备名字已经变成了 s3c-sdhci

struct s3c_sdhci_platdata s3c_hsmmc0_def_platdata = {  .max_width = 4,  .host_caps = (MMC_CAP_4_BIT_DATA | MMC_CAP_MMC_HIGHSPEED |     MMC_CAP_SD_HIGHSPEED),  .cfg_ext_cd = setup_sdhci0_irq_cd,  .detect_ext_cd = detect_sdhci0_irq_cd,  .ext_cd  = S3C_EINT(13), }; struct platform_device s3c_device_hsmmc0 = {  .name  = "s3c-sdhci",  .id  = 0,  .num_resources = ARRAY_SIZE(s3c_hsmmc_resource),  .resource = s3c_hsmmc_resource,  .dev  = {   .dma_mask  = &s3c_device_hsmmc_dmamask,   .coherent_dma_mask = 0xffffffffUL,   .platform_data  = &s3c_hsmmc0_def_platdata,  }, };

 

它会在系统初始化注册deivce.

 而platform_driver定义在 drivers/mmc/host/sdhci-s3c.c

 

//drivers/mmc/host/sdhci-s3c.c

static struct platform_driver sdhci_s3c_driver = {
 .probe  = sdhci_s3c_probe,
 .remove  = __devexit_p(sdhci_s3c_remove),
        .suspend        = sdhci_s3c_suspend,
        .resume         = sdhci_s3c_resume,
 .driver  = {
  .owner = THIS_MODULE,
  .name = "s3c-sdhci",
 },
};