linux那些事儿之我是i2c -- Gsenser(三)_linux那些事儿 i2c-优快云博客

本文深入探讨Linux驱动模型中的I2C驱动，讲解如何从i2c_register_driver开始，通过i2c_device_match进行驱动与设备匹配，最终调用i2c_device_probe函数进行设备探测。分析了i2c_driver结构体和i2c_device_probe的工作流程，包括设备验证、初始化等步骤。

3.是谁掀起了你的盖头来？
    对linux驱动模型有一点了解的兄弟知道，一个驱动，特别是挂上总线的驱动，
真正开始执行都是始于probe函数。我们这里的lis3lv02d_i2c驱动，是挂在系统的i2c总线上的，
因而也就会从probe开始执行。那么是谁来调用这个probe内？就好像驱动通过总线介绍，嫁给了设备，
那到底是哪个设备去掀起驱动的红盖头呢？我们从i2c_register_driver看开去。
代码在kernel/driver/i2c/i2c-core.c中：
872 /*
873 * An i2c_driver is used with one or more i2c_client (device) nodes to access
874 * i2c slave chips, on a bus instance associated with some i2c_adapter.
875 */
876
877 int i2c_register_driver(struct module *owner, struct i2c_driver *driver)
878 {
879   int res;
880
881   /* Can't register until after driver model init */
882   if (unlikely(WARN_ON(!i2c_bus_type.p)))
883     return -EAGAIN;
884
885   /* add the driver to the list of i2c drivers in the driver core */
886   driver->driver.owner = owner;
887   driver->driver.bus = &i2c_bus_type;
888
889   /* When registration returns, the driver core
890    * will have called probe() for all matching-but-unbound devices.
891    */
892   res = driver_register(&driver->driver);
893   if (res)
894     return res;
895
896   pr_debug("i2c-core: driver [%s] registered\n", driver->driver.name);
897
898   INIT_LIST_HEAD(&driver->clients);
899   /* Walk the adapters that are already present */
900   mutex_lock(&core_lock);
901   bus_for_each_dev(&i2c_bus_type, NULL, driver, __attach_adapter);
902   mutex_unlock(&core_lock);
903 ///WTT DEBUG
904 printk("***** WTT DEBUG i2c_register_driver to return 0\