以问答的形式来理解摄像头框架流程

问：aw_camera.xml中配置的多个摄像头在哪里匹配？

答：sensor.c(vendor)通过iotcl到底层在msm_sensor_driver_probe去获取dtsi中配置的g_sctrl

kernel\msm-3.18\drivers\media\platform\msm\camera_v2\sensor\msm_sensor_init.c

msm_sensor_init_subdev_do_ioctl -> msm_sensor_init_subdev_ioctl -> msm_sensor_driver_cmd -> msm_sensor_driver_probe

问：g_sctrl里面的值什么时候赋值？

答：通过平台driver进来解析dts时复制

kernel\msm-3.18\drivers\media\platform\msm\camera_v2\sensor\msm_sensor_driver.c

msm_sensor_driver_platform_probe -> msm_sensor_driver_parse -> msm_sensor_driver_get_dt_data

问：g_sctrl里面的sensor_i2c_client内容关于i2c通讯部分哪里来的？

答：camera_v2\sensor\cci\msm_cci.c中通过platform_driver_register获取i2c相关的配置，msm_sensor_driver_platform_probe里面会对g_sctrl里面的内容都填充

msm_sensor_driver_platform_probe -> msm_sensor_driver_parse -> msm_sensor_init_default_params -> s_ctrl->sensor_i2c_client->i2c_func_tbl =

&msm_sensor_cci_func_tbl;

问：/dev/media*和/dev/video*和/dev/v4l-subdev*在哪里注册的？

答：kernel\msm-3.18\drivers\media\platform\msm\camera_v2\msm.c代码里注册的*0，匹配msm8937-camera.dtsi里面的qcom,msm-cam

驱动里面注册：msm_probe -> media_device_register(/dev/media*)

->video_register_device -> __video_register_device(里面注册了主设备号81的设备和/sys/class/video4linux/video* v4l-subdev*)

kernel\msm-3.18\drivers\media\platform\msm\camera_v2\sensor\msm_sensor_driver.c里面调用camera_init_v4l2注册了真正的摄像头：

msm_sensor_driver_probe -> msm_sensor_driver_create_v4l_subdev -> camera_init_v4l2 -> media_device_register

问：如何解决 mmm libs提示'sensor_lib.h' file not found 或者ALOGE未定义

答：1.#include

2. LOCAL_C_INCLUDES := $(LOCAL_PATH)/../../../../../../../../mm-camerasdk/sensor/includes/

问：摄像头的两个相关服务代码分别在哪

答：

server：cameraserver

frameworks\av\camera\cameraserver\main_cameraserver.cpp

server：mm-qcamera-daemon

vendor\qcom\proprietary\mm-camera\mm-camera2\server-imaging\server.c

main -> server_process_module_sensor_init -> module_sensor_init(module_sensor.c)-> sensor_init_probe(sensor_init.c) -> sensor_init_xml_probe -> sensor_probe -> sensor_load_library ->

问：为什么mm-qcamera-daemon是32位的应用程序，编译取决哪里？

答：Android.mk加了下面这句所以编译出来是32位的应用程序

LOCAL_32_BIT_ONLY := true

问：vendor\qcom\proprietary\mm-camera\mm-camera2\media-controller\modules\sensors\sensor\module\sensor.c中调用的ioctrl对应驱动程序的哪里?

答：kernel\msm-3.18\drivers\media\platform\msm\camera_v2\sensor\msm_sensor.c

msm_sensor_subdev_fops_ioctl -> msm_sensor_subdev_do_ioctl -> msm_sensor_subdev_ioctll -> msm_sensor_config32

kernel\msm-3.18\drivers\media\platform\msm\camera_v2\sensor\msm_sensor_driver.c msm_sensor_driver_create_i2c_v4l_subdev中有设置了compat_ioctl32:

问：配置的xml在哪里解析

答：

\vendor\qcom\proprietary\mm-camera\mm-camera2\media-controller\modules\sensors\chromatix\module\chromatix_manager.c

addLib -> addLib_getSymbol -> load_chromatix (chromatix_sub_module.c)