通用驱动i2c-dev分析

参考资料：

Linux驱动程序: drivers/i2c/i2c-dev.c
I2C-Tools-4.2: https://mirrors.edge.kernel.org/pub/software/utils/i2c-tools/
AT24cxx.pdf

通用的i2c-dev驱动走的还是字符设备驱动那一套，怎么编写字符设备驱动程序？

创建file_operations结构体吗，在里面填充drv_open/drv_read/drv_ioctl等函数
入口函数调用register_chrdev(major, &fops, name)注册file_operations结构体
创建类class_create
在类型创建设备节点 device_create

i2c-dev.c注册过程分析

i2c-dev驱动的注册过程

../../_images/047_i2c-dev_register.png image-20210226164128588

file_operations函数分析

i2c-dev.c的核心：

static const struct file_operations i2cdev_fops = {
	.owner		= THIS_MODULE,
	.llseek		= no_llseek,
	.read		= i2cdev_read,
	.write		= i2cdev_write,
	.unlocked_ioctl	= i2cdev_ioctl,
	.compat_ioctl	= compat_i2cdev_ioctl,
	.open		= i2cdev_open,
	.release	= i2cdev_release,
};