《精通Linux设备驱动开发》——i2c协议（代码1）

/* 代码清单8-2 *//* 初始化EEPROM驱动程序 *//* Driver entry points */static struct file_operation eep_fops = {.owner    = THIS_MODULE,.llseek   = eep_llseek,.read     = eep_read,.ioctl    = eep_ioctl,.open     = eep_open,.release  = eep_release,.write    = eep_write,};static dev_t dev_number;/* Allotted Device Number */static struct class *eep_class;/* Device class *//* Per-device client data structure for each memory bank supported by the driver */struct eep_bank{struct i2c_client *client;/* i2c client for this bank */unsigned int addr;/* Slave address of this bank */unsigned short current_pointer;/* File pointer */int bank_number;/* Actual memory bank number *//* ... */};#define NUM_BANKS    2/* Two supported banks */#define BANK_SIZE    2048/* Size of each bank */struct eep_bank *ee_bank_list;/* List of private data structures,one per bank *//* Device Initialization */int __init eep_init(void){int err, i;/* Allocate the per-device data structure ,ee_bank */ee_bank_list = kmalloc(sizeof(struct ee_bank) * NUM_BANKS, GFP_KERNEL);memset(ee_bank_list, 0, sizeof(struct ee_bank) * NUM_BANKS);/* Register and create the /dev interfaces to access the EEPROM banks. * Refer back to Chapter 5,"Character Drivers" for more details */if( alloc_chrdev_region(&dev_numbers, 0, NUM_BANKS, "eep") < 0 ){printk(KERN_DEBUG "Can't register device\n");return -1;}eep_class = class_create(THIS_MODULE, DEVICE_NAME);for( i = 0; i < NUM_BANKS, i++ ){/* Connect the file operations with cdev */cdev_init(&ee_bank[i].cdev, &eep_fops);/* Connect the major/minor number to the cdev */if( cdev_add(&ee_bank[i].cdev, (dev_number + i), 1) ){printk("Bad kmalloc\n");return 1;}device_create(eep_class, NULL, MKDEV(MAJOR) (dev_number), i),    "eeprom%d", i );}     /* Inform the i2c core about out existence.See the section       "Probing the Device" for the definition of eep_driver */               err = i2c_add_driver(&eep_driver);if( err ){    printk("Registering I2C driver failed, errno is %d\n", err);    return err; }printk("EEPROM Driver Initialized.\n");return 0;}