IMX8M MINI: How to configure MIPI-CSI timing clocks for AR0234 sensor

[inigo_irisbond]

Hi,

We are evaluating the onsemi AR0234 sensor. Onsemi offers two presets to run the sensor at 120fps and 30fps. These presets change the image capture settings and MIPI timings. Likewise, when I use the 120fps preset, everything works fine and the IMX8 receives images, but when I use the 30fps preset, I don't receive images. I understand this is because I am not changing the MIPI timing settings on the IMX8 side. I don't know where I should make these changes, can you help me? I am attaching the dts and the imx6s_capture.c driver which is the one I am using.

[JorgeCas]

Hello,

Maybe you should try using the corresponding patch to support AR0234 sensor with iMX8M mini, I will attach it on this post.

Best regards.

[inigo_irisbond]

Thanks, but in my HW I don't have the ap1302 coprocessor. The imx8m mini is routed directly to the Ar0234 via the mipi csi2 bus and I2C.

[inigo_irisbond]

Hola Jorge,

podríamos organizar una llamada para explicarte brevemente el problema y analizar las posibles soluciones?

Gracias!

[JorgeCas]

Hello,

All the support is through community/email.

Could you please share me the steps and commands that you are using to capture with 120 fps and 30 fps?

Which OS and version are you using?

Best regards.

[inigo_irisbond]

About the OS:

# cat /etc/*-release
NAME=Buildroot
VERSION=2020.08-git-00515-g208d3eb045-dirty
ID=buildroot
VERSION_ID=2020.08-git
PRETTY_NAME="Buildroot 2020.08-git"

Thanks and regards!

[JorgeCas]

Hello,

Got it, thank you for the information.

As you mentioned on previous comments you need to make sure that the sensor output stream is within the SoC MIPI capture capability. 

Please refer to than information on attached PDF file on sections ''MIPI capture capabilities"" and "Porting new camera".

Best regards.

[inigo_irisbond]

I have read the documentation and I still have the same doubts. 

According to this sentence, when reducing the fps you should maintain compatibility

"The incoming camera data rate and pixel clock must be less than or equal to the Rx DPHY bandwidth and pixel clock." 

I have also tried to change the parameter csis-hs-settle = <30>; to 5 following the tables of the datahseet, but it does not give results.

Could you help me more, about where I should make changes to be compatible with other timings of a new mipi configuration?

Thanks and regards!

[JorgeCas]

Hello, apologize for the delay.

csis-hs-settle does not affect directly the fps received from the camera, it changes MIPI Serial clock Frequency.

Researching further, your device tree configuration and the way that you are trying to capture from the camera at different frame rates seems to be ok, but the camera FPS depends on camera register config and you need consult it from Onsemi.

Best regards.

[inigo_irisbond]

If we set the MIPI speed to 22.5MHz, what value should I select in csis-hs-settle?

[inigo_irisbond]

About the configuration of the AR0234 at 30fps is a configuration given by Onsemi that we have validated in their EVK. The next step we wanted to do is to start the configuration with IMX8m mini but for some reason it doesn't work. The MIPI setting calculated for 120fps does work but it only changes the packet reception time. Do you know where I can set this on the IMX8m mini?