Missing t194-p2822-0000-a00.dtsi?

Robotics & Edge Computing Jetson & Embedded Systems Jetson AGX Xavier
1

Dear Tegra Device Tree Experts,

From the online documentation NVIDIA Jetson Linux Driver Package Software Features in both 32.2 and 32.3 releases, in Sensor Software Driver Programming Guide → Device Registration → Using the Main Platform Device Tree File :

In step #3 :

...
3. Locate and edit the .dtsi file:
<top>/hardware/nvidia/platform/t19x/galen/kernel-dts/common/t194-p2822-0000-a00.dtsi
...

I cannot really find the above file but “tegra194-p2822-0000-a00.dtsi”. Are they the same? Could anyone confirm me if the documentation is correct?

Beside, in step #4 :

...
4. Replace the following line:
#include "tegra194-p2822-camera-modules.dtsi"
With an #include statement specifying the DTSI file for your new device.
...

I can find that “tegra194-p2822-camera-modules.dtsi” is only included in the following files :

kernel_src/hardware/nvidia/platform/t19x/galen/kernel-dts/tegra194-p2888-0006-p2822-0000.dts
17:#include "common/tegra194-p2822-camera-modules.dtsi"

kernel_src/hardware/nvidia/platform/t19x/galen/kernel-dts/tegra194-p2888-as-0006-p2822-0000.dts
17:#include "common/tegra194-p2822-camera-modules.dtsi"

kernel_src/hardware/nvidia/platform/t19x/galen/kernel-dts/tegra194-p2888-0001-p2822-0000.dts
16:#include "common/tegra194-p2822-camera-modules.dtsi"

So, for adding my custom sensor’s devicetree, which of above files should I modify the inclusion, please? I guess that it also relates to the Jetpack/L4T version as well, am I right?

Moreover, the “tegra194-cvb-p2822-0000-a00.dtsi” is included in “tegra194-p2822-0000-a00.dtsi”

kernel_src/hardware/nvidia/platform/t19x/galen/kernel-dts/common/tegra194-p2822-0000-a00.dtsi
14:#include <t19x-common-modules/tegra194-cvb-p2822-0000-a00.dtsi>

Should I modify it as well?

Also, could someone be kind to explain me the signification/convention of different numbers within following filenames if possible, please ?

$ ls kernel_src/hardware/nvidia/platform/t19x/galen/kernel-dts/
tegra194-p2888-0001-e3366-1199.dts              tegra194-p2888-0001-p2822-0000-maxn.dts
tegra194-p2888-0001-p2822-0000.dts              tegra194-p2888-0006-p2822-0000.dts
tegra194-p2888-0001-p2822-0000-imx185_v1.dts    tegra194-p2888-as-0006-p2822-0000.dts
tegra194-p2888-0001-p2822-0000-imx274-hdmi.dts

Thanks in advance,

2

Hi,
First, Thanks for your finding.
The dts should be the tegra194-p2888-0001-p2822-0000.dts,
PLease reference to below link to check the patch for Using the Main Platform Device Tree File

https://devtalk.nvidia.com/default/topic/1071818/jetson-agx-xavier/dev-node-not-populated-for-imx274/post/5430630/#5430630

3

Hi ShaneCCC,

Thanks for your confirmation and the link. Now I have a clear vision of how to add custom sensor’s devicetree using both Plugin Manager or Main Platform Device Tree. I could also find the board naming convention as well.

Possibly I will solicitatiate your support for the different parameters within the DTS(I).

Many thanks,
Khang