Linux Bus device driver model

This article, through the platform bus device model as an example, explains the bus device driver Model:

Platform_device_ Register role: 1. Put the device into the bus's device chain List 2. Remove each driver from the bus's driver list, and use the bus's match function to determine if driver can support this device3. driver function PL called probe if supported Atform_driver_  Register role: 1. Put driver into bus driver link List 2. Remove each device from the bus's device list and use the bus's match function to determine if the driver can support this device3. Driver function to invoke if supported One, device driver 1. Constructs and initializes the platform device resource structure body resource

struct resource led_resource[] = {     [0] = {          0x56000000,           0x5600000081,          = ioresource_mem,     },     [ 1] = {          5,          5,          = Ioresouce_ IRQ,     },};

2. Construct and initialize the platform device structure body Platform_device

 struct  platform_device led_dev = {. Name 
    =  myled   "      =-1  ;     . Num_resource  = Array_size (Led_resource);          . Resource  = Led_resource,. Dev  = = Led_release,},};  /*   The release function can do nothing, but cannot be null  */ static  void  led_release (struct  device * dev) {}  

3. Register platform Device

Platform_device_register (&led_dev);

Second, driver driver 1. Constructs and initializes the platform-driven structure body platform_driver

struct platform_driver led_drv = {     = led_probe,     = Led_remove,     = {           " myled " ,     },};

2. Construct and initialize the file_operations structure

Static structFile_operations Led_fops ={. Owner= This_module,/*This is a macro that is automatically created when you push the module to compile the __this_module variable*/. Open=Led_open,. Write=Led_write,};Static intLed_open (structInode *inode,structFile *file) {     //PRINTK ("first_drv_open\n");     /*configured as Output*/*gpio_con &= ~ (0x3<< (pin*2)); *gpio_con |= (0x1<< (pin*2)); return 0; }Staticssize_t Led_write (structFile *file,Const Char__user *buf, size_t count, loff_t *PPOs) {     intVal; //PRINTK ("first_drv_write\n");Copy_from_user (&val, buf, Count);//Copy_to_user ();     if(val = =1)     {          //Lighting*gpio_dat &= ~ (1<<pin); }     Else     {          //extinguishing lamp*gpio_dat |= (1<<pin); }         return 0;}

3. Implementing the probe function of the platform_driver structure

Static intLed_probe (structPlatform_device *Pdev) {     structResource *Res; *Platform_get_resource*@dev:p Latformdevice*@type: ResourceType*@num: Resourceindex res= Platform_get_resource (Pdev, Ioresource_mem,0); Gpio_con= Ioremap (res->start,res->end-res->start+1); Gpio_dat= Gpio_con +1; Res= Platform_get_resource (Pdev, IORESOURCE_IRQ,0) Pin= res->start; Major= Register_chrdev (0,"myled", &led_fops); CLS= Class_create (This_module,"myled"); Device_create (CLS, NULL, MKDEV (Major,0), NULL,"led");}

4. Register platform Driver Driver

Platform_driver_register (&LED_DRV);