platform-devices-drivers

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了解platform-device及platform-drivers用法及定義

更新記錄

item note
20160629 第一版

目錄

platform

  • 來源, linux-3.0.y/Documentation/driver-model/platform.txt
  • [platform.txt]

  • 註冊設備:

    • platform_device_register(): 註冊設備硬件，告訴kernel，當前有什麼設備
    • platform_driver_register(): 註冊設備的驅動程序

  • 程序如下:

    • 當個設備connect後
    • device和driver的兩條綫上都有匹配(由name來匹配)
    • 匹配上(即binding)，並且開始使用driver的probe等函數進行進行硬件初始化工作

platform device

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[rectangle setX: 10 y: 10 width: 20 height: 20];

  struct platform_device {                                                 
      const char  * name;                                                  
      int     id;                                                          
      struct device   dev;                                                 
      u32     num_resources;                                               
      struct resource * resource;                                          
                                                                           
      const struct platform_device_id *id_entry;                           
                                                                           
      /* MFD cell pointer */                                               
      struct mfd_cell *mfd_cell;                                           
                                                                           
      /* arch specific additions */                                        
      struct pdev_archdata    archdata;                                    
  };
  • name : 在做driver及device比對時用(即是參考此name)
    • platform_device.name : 用來作driver matching
  • id : 當name比較相同時，在probe還可以參考id
    • platform_device.id : the device instance number
  • resource: SOC的IOBASE/IRQ為固定的，由此設定

platform driver

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struct platform_driver {                                                 
   int (*probe)(struct platform_device *);                              
    int (*remove)(struct platform_device *);                             
    void (*shutdown)(struct platform_device *);                          
    int (*suspend)(struct platform_device *, pm_message_t state);        
    int (*resume)(struct platform_device *);                             
    struct device_driver driver;                                         
    const struct platform_device_id *id_table;                           
};
  • 提供callback function: probe, remove等

platform api

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extern int platform_device_register(struct platform_device   *);
extern void platform_device_unregister(struct platform_device *); 
extern int platform_driver_register(struct platform_driver *);
extern void platform_driver_unregister(struct platform_driver *);
  • Whenever a device a registered. the driver for that bus are checked for matches.
  • When ad driver is regiestered using platform_device_register.
    • all unbund device on that bus are checked for matches.
  • Register a driver using platform_driver_probe.
  • 當device上線時第一次動作為probe

platfrom_device_register flow

[platform device register flow]

platfrom_driver_register flow

[platform driver register flow]

hi3521 stmmac example

stmmac module

  • 當module init時註冊設備
[stmmac module]

stmmac init module

  • 先platform_device_register
  • 再platform_drvier_register
[init module]

stmmac platform device

  • phy device data
    • 設定相關phy0_id及interface
[phy device data]
  • ethernet device data
    • 設定相關gmac的IRQ及IOBASE
[ethernet device data]

stmmac platfrom driver

  • 設定相關probe及remove
[platfrom driver]

參考來源