linux SDIO實現

在Linu 2.6.21的SDIO驅動，它是除了是mmc_host的驅動外，仍是一個Platform驅動.身兼兩職.

在這個版本中，首先是定義三個platform_deivce 以註冊到系統當中。可是它定義在

  arch/arm/plat-s3c24xx/devs.c (這會讓人感當至關迷惑),它建立是 s3c-hsmmc設備

 

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 定義在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函數中，會進行一系列的初始化操做.

 

Linux 2.6.28的SDIO的實現

  Linux 2.6.28又作了進一步調整，原來的s3c-hsmmc的設備和驅動已經放棄，原來在s3c-hsmmc.c 已經成爲殘餘代碼，雖然在內核中，可是不會加入Makefile編譯。

其新的platform_device 定義分佈定義在 dev-hsmmc.c /dev-hsmmc1.c / dev-hsmmc2.c,能夠看到設備名字已經變成了 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,  }, };

 

它會在系統初始化註冊deivce.

 而platform_driver定義在 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",
 },
};