Device-tree overlay to supports multiple cameras

[wqr346077095]

Hi，
关于camera 上的 Device-tree overlay有一些疑惑，参考链接Device-tree overlay。
我们的需求是 将xxx-摄像头模组连接到orin，上电设备，无需其他操作，即能加载对应模组的驱动，使用该模组。
关于上述链接的文档，我们的理解为
1）、准备 xxx-overlay.dts, 该文件描述了xxx-摄像头模组， 编译烧录到orin的指定位置
2）、带有eeprom的xxx-摄像头模组，eeprom中已存储好“valid camera ID“， 在相关文件定义好该eeprom所挂载的总线和i2c地址。
3）、上电设备，系统启动，先从xxx-摄像头模组上的eeprom中读取到“valid camera ID”，然后决定加载对应的 xxx-overlay.dts。
符合我们的需求。

现在遇到的问题是
1）、我们需要在哪个文件(tegra234-p3711-eeprom.dtsi 这个么？)告诉内核我们模组具有eeprom，以及eeprom的总线和地址
2）、eeprom的存储信息的格式是什么？有什么相应的规则么？比如哪个寄存器存储什么信息（ids?）、命名规则?
3）、如果我们想要实现该功能，是只需要修改内核设备树文件就可以了吗？还需要修改、编译UEFI的文件么？
有更为详细的相关文档可以参考么？

[carolyuu]

Hi,

For the camera basic functionality first needs to check the device and driver configuration.
You can reference to below program guide for the detailed information of device tree and driver implementation.
https://docs.nvidia.com/jetson/archives/r36.3/DeveloperGuide/SD/CameraDevelopment/SensorSoftwareDriverProgramming.html?highlight=programing#sensor-software-driver-programming

Please refer to Applications Using V4L2 IOCTL Directly by using V4L2 IOCTL to verify basic camera functionality.
https://docs.nvidia.com/jetson/archives/r36.3/DeveloperGuide/SD/CameraDevelopment/SensorSoftwareDriverProgramming.html?highlight=programing#to-run-a-v4l2-ctl-test

Once confirm the configure and still failed below link help to get log and some information and some tips for debug.
https://elinux.org/Jetson/l4t/Camera_BringUp#Steps_to_enable_more_debug_messages

Thanks!

[ShaneCCC]

With UEFI boot enabled in this release, the plugin-manager is no longer supported. Now, you need to create a device-tree overlay file to register the camera module. If your camera module has on-board EEPROM and is programmed with a valid camera ID, you can use that to apply the overlay for specific camera module and update the device-tree entries with proper information at runtime. To change camera modules, power down the device, replace the camera module, and then reboot. The new module works automatically.