Hello,

how can I access the v4l2 controls from my camera sensor?

If I use v4l2-ctl -l. I get no output.

What I know is following:

I have a bridge driver which is connect with a mipi csi2 driver.
And the mipi csi2 driver is connect with the camera sensor for example ov5640.

I have only a /dev/video0 device.

What do you mean by controls exactly?

Did you have a look into /sys?

Yes I have looked into sys file system, but I have only a /dev/video0 device.

The v4l2 API say:
When a sub-device is registered with a V4L2 driver by calling v4l2_device_register_subdev() and the ctrl_handler fields of both v4l2_subdev and v4l2_device are set, then the controls of the subdev will become automatically available in the V4L2 driver as well. If the subdev driver contains controls that already exist in the V4L2 driver, then those will be skipped (so a V4L2 driver can always override a subdev control).

But my driver are asynchronous registered.

My driver structure looks following:

bridge driver -> csi-driver -> sensor driver (includes controls)
register-async-notifer for csi driver register-async-notifer for sensor driver
register video device

Have you inspected lspci -vv and lsusb -vv and dmesg and lsmod to find out if everything is as it is expected to be?

Is it a custom kernel or a distro kernel? Which distro do you use?

Try
What does it say?

Thank you for your help,
but I found out that this problem comes from the driver.

Try this: https://linuxtv.org/downloads/v4l-dv...-controls.html