platform_driver

PNP 기능을 플랫폼 드라이버라는 형태로 지원한다.

 

드라이버의 기본동작을 구현하기 위한 자료구조체

/usr/src/linux-3.19.4/include/linux/platform_device.h

 

174 struct platform_driver { 175     int (*probe)(struct platform_device *); 176     int (*remove)(struct platform_device *); 177     void (*shutdown)(struct platform_device *); 178     int (*suspend)(struct platform_device *, pm_message_t state); 179     int (*resume)(struct platform_device *); 180     struct device_driver driver; 181     const struct platform_device_id *id_table; 182     bool prevent_deferred_probe; 183 };   490 #define PLATFORM_NAME_SIZE  20 491 #define PLATFORM_MODULE_PREFIX  "platform:" 492     493 struct platform_device_id { 494     char name[PLATFORM_NAME_SIZE]; 495     kernel_ulong_t driver_data; 496 };       보통 사용 예  static struct platform_driver test_driver= {   .probe = test_probe,   .remove= test_remove,   .suspend= test_suspend   .resume = test_resume,   .driver ={               .name = TEST_DEVICE_DRIVER_NAME,   }, };

 

 

• probe() 디바이스가 추가 되었을 때 처리하는 함수를 지정
• remove() 디바이스가 제거 되었을 때 처리하는 함수를 지정
• shutdown() 디바이스의 동작을 중지 시킬때 처리하는 함수
• resume() 디바이스의 동작을 재시작 시킬 때 처리하는 함수
• driver 구조체 내부의 name 필드만 보통 지정, 나머지 필드는 커널 내부에서 관리되면서 채워진다.
• id_table  probe()함수가 호출되는 과정에서 해당 디바이스를 구별하고 처리하기 위한 내부 데이터를 지정하는 목적

 

 

 

플랫폼 드라이버 구조체 정보는 다음과 같은 함수로 커널에 등록되거나 제거된다.

• int platform_driver_register(struct platform_driver *pdev);
• void platform_dirver_unregister(struct platform_driver *pdev);

 

    platform_driver_register() 함수는  : pdev 정보를 커널 내부에 등록하기 위해서 사용되므로 보통 모듈 초기화 함수에서 사용된다. 반환값이 0이면 정상이다.

 

188 /* 189  * use a macro to avoid include chaining to get THIS_MODULE 190  */ 191 #define platform_driver_register(drv) \ 192     __platform_driver_register(drv, THIS_MODULE) 193 extern int __platform_driver_register(struct platform_driver *, 194                     struct module *); 195 extern void platform_driver_unregister(struct platform_driver *);     32 #ifdef MODULE  33 extern struct module __this_module;  34 #define THIS_MODULE (&__this_module)  35 #else  36 #define THIS_MODULE ((struct module *)0)  37 #endif

 

다른버전 ----4.0.2

truct 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; bool prevent_deferred_probe; }; struct platform_device { const char *name; int id; bool id_auto; struct device dev; u32 num_resources; struct resource *resource; const struct platform_device_id *id_entry; char *driver_override; /* Driver name to force a match */ /* MFD cell pointer */ struct mfd_cell *mfd_cell; /* arch specific additions */ struct pdev_archdata archdata; }; /* * use a macro to avoid include chaining to get THIS_MODULE */ #define platform_driver_register(drv) \ __platform_driver_register(drv, THIS_MODULE) extern int __platform_driver_register(struct platform_driver *, struct module *); extern void platform_driver_unregister(struct platform_driver *); /** * __platform_driver_register - register a driver for platform-level devices * @drv: platform driver structure * @owner: owning module/driver */ int __platform_driver_register(struct platform_driver *drv, struct module *owner) { drv->driver.owner = owner; drv->driver.bus = &platform_bus_type; if (drv->probe) drv->driver.probe = platform_drv_probe; if (drv->remove) drv->driver.remove = platform_drv_remove; if (drv->shutdown) drv->driver.shutdown = platform_drv_shutdown; return driver_register(&drv->driver); } EXPORT_SYMBOL_GPL(__platform_driver_register); /** * platform_driver_unregister - unregister a driver for platform-level devices * @drv: platform driver structure */ void platform_driver_unregister(struct platform_driver *drv) { driver_unregister(&drv->driver); } EXPORT_SYMBOL_GPL(platform_driver_unregister); static inline struct platform_device *platform_device_register_simple( const char *name, int id, const struct resource *res, unsigned int num) { return platform_device_register_resndata(NULL, name, id, res, num, NULL, 0); } static inline struct platform_device *platform_device_register_resndata( struct device *parent, const char *name, int id, const struct resource *res, unsigned int num, const void *data, size_t size) { struct platform_device_info pdevinfo = { .parent = parent, .name = name, .id = id, .res = res, .num_res = num, .data = data, .size_data = size, .dma_mask = 0, }; return platform_device_register_full(&pdevinfo); } ///usr/src/linux-4.0.2/drivers/base/platform.c EXPORT_SYMBOL_GPL(platform_device_register_full); struct platform_device *platform_device_register_full( const struct platform_device_info *pdevinfo) { int ret = -ENOMEM; struct platform_device *pdev; pdev = platform_device_alloc(pdevinfo->name, pdevinfo->id); if (!pdev) goto err_alloc; pdev->dev.parent = pdevinfo->parent; ACPI_COMPANION_SET(&pdev->dev, pdevinfo->acpi_node.companion); if (pdevinfo->dma_mask) { /* * This memory isn't freed when the device is put, * I don't have a nice idea for that though. Conceptually * dma_mask in struct device should not be a pointer. * See http://thread.gmane.org/gmane.linux.kernel.pci/9081 */ pdev->dev.dma_mask = kmalloc(sizeof(*pdev->dev.dma_mask), GFP_KERNEL); if (!pdev->dev.dma_mask) goto err; *pdev->dev.dma_mask = pdevinfo->dma_mask; pdev->dev.coherent_dma_mask = pdevinfo->dma_mask; } ret = platform_device_add_resources(pdev, pdevinfo->res, pdevinfo->num_res); if (ret) goto err; ret = platform_device_add_data(pdev, pdevinfo->data, pdevinfo->size_data); if (ret) goto err; ret = platform_device_add(pdev); if (ret) { err: ACPI_COMPANION_SET(&pdev->dev, NULL); kfree(pdev->dev.dma_mask); err_alloc: platform_device_put(pdev); return ERR_PTR(ret); } return pdev; }

/usr/src/linux-4.0.2/drivers/base/platform.c

 

 

 

 

 

 

 

 

참조 : B003_디바이스 드라이버 모듈 (유영창)