v4l2_i2c_new_subdev_board接口分析(侧重I2C设备的探测)

最新推荐文章于 2025-06-11 16:57:00 发布

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最新推荐文章于 2025-06-11 16:57:00 发布 · 5.7k 阅读

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#c #struct #module #null #callback #function

本文详细分析了V4L2框架中用于添加I2C设备的v4l2_i2c_new_subdev_board接口，讲解了如何通过该接口探测和注册I2C设备，涉及到模块加载、I2C客户端创建、驱动程序的probe过程等关键步骤。

V4L2中增加I2C设备接口：v4l2_i2c_new_subdev_board接口分析 struct v4l2_subdev *v4l2_i2c_new_subdev_board(struct v4l2_device *v4l2_dev, struct i2c_adapter *adapter, const char *module_name, struct i2c_board_info *info, const unsigned short *probe_addrs) { ........ if (module_name) request_module(module_name); //加载I2C驱动模块 /* Create the i2c client */ if (info->addr == 0 && probe_addrs) client = i2c_new_probed_device(adapter, info, probe_addrs); else client = i2c_new_device(adapter, info); //在此接口中会增加sysfs，会把驱动和设备关联起来，并会调用于I2C驱动中的probe接口 /* Note: by loading the module first we are certain that c->driver will be set if the driver was found. If the module was not loaded first, then the i2c core tries to delay-load the module for us, and then c->driver is still NULL until the module is finally loaded. This delay-load mechanism doesn't work if other drivers want to use the i2c device, so explicitly