Errror linking Omnivision video driver

[sir_hugo]

Hi, 

I'm new to nRF/Zephyr development and trying to integrate the OV7670 camera with the nRF52840 board. Since there was no driver for this particular camera I ported the one available for OV7725 in the Zephyr SDK. As far as I know I've adjusted all the kconfig files correctly and I've set  CONFIG_VIDEO_OV7670=y in the prj.conf file. The driver seems to be getting compiled when performing west build but I get the following error when building main.c "src/main.c:90: undefined reference to `ov7670_init_0'". I have added the #include <drivers/video.h> so I'm not sure why I'm getting this error. Have I missed a configuration setting?

[Øivind]

Hi,

Which sample/application are you trying to access the driver from?

Could you list all the files you edited/added? Have you edited the Kconfig and CMakeLists files correctly? Have you enabled the device in the devicetree correctly, for example using an overlay file? Have you added a .yaml file to the bindings? 

This can be a little complicated if you are new to zephyr drivers, so let me know if there is anything you need help with.

[sir_hugo]

I have a basic application to initiate the camera. I've added a file Kconfig.ov7670 and added 'source "drivers/video/Kconfig.ov7670"' to the Kconfig file. In CMakeLists.txt I've added 'zephyr_library_sources_ifdef(CONFIG_VIDEO_OV7670 ov7670.c)'. I've also created an overlay file for the camera. I haven't added a .yaml file, there's just the sample.yaml.

[Øivind]

Ok, you will need a .yaml file at the location I linked in my previous comment, zephyr/dts/bindings/video.

Also make sure you set "CONFIG_VIDEO=y" in the prj.conf.

[sir_hugo]

I've added the file and CONFIG_VIDEO=y but it hasn't solved the problem.

[Øivind]

Ok, in that case I think it would be easiest if you showed me the files (kconfig, cmakelists, .yaml, driver source and application), and I can see if I spot any issues. If you want you can add them to a zip archive and attach it inline with text using Insert->Image/video/file.

[sir_hugo]

Ok, don't judge me :)ov7670.zip

[Øivind]

Don't worry, I would never judge someone who is trying to learn. :)

The first problem is in your main.c, you can't call the init function of a driver like that. Try this instead:

const struct device *dev;
dev = device_get_binding("ov7670");
if (dev == NULL) {
    printk("Error: Could not get ov7670 device binding\n");
}

The CMakeLists.txt I wanted to see was the one in zephyr/drivers/video. But just add this line to it if you haven't already:

zephyr_library_sources_ifdef(CONFIG_VIDEO_OV7670	ov7670.c)

I also wanted to see the .yaml file you put in zephyr/dts/bindings/video, but as long as it's there it should be fine.