Add support for Raspberry Pi Camera Module v3 to Kirkstone (compatibility patch)

[Jessseee]

The imx708 devicetree layer is required for use of the Raspberry Pi Camera Module v3. This was implemented in #1158 on master. However, the dts file is not included with Kernel 5.10. Therefore, to port these changes to Kirkstone, I added a dynamic layer to install the imx708 devicetree overlay when building for Linux kernel 5.10. Also see #1172 for more context.

[agherzan]

Could you add the rationale and context in the description?

[agherzan]

Reopened as I've closed it by mistake.

[Jessseee]

Could you add the rationale and context in the description?

I hope this is clear enough.

[mhazley]

@Jessseee made it here from the Balena thread? Any way we can help get this over the line, we'd like to use camera v3 on Balena OS on Pi4

[agherzan]

I'm generally happy with this, but we will need to first land it via a review in master. It looks good to me otherwise.

[mhazley]

I'm generally happy with this, but we will need to first land it via a review in master. It looks good to me otherwise.

Is is possible this is already done via #1158?

[agherzan]

That's what I hoped and thought, but this seems to include more things. @Jessseee can you explain the backport so I understand where we are with this?

I suspect it is something along the "we don't have the right dtb in the kirkstone kernel versions" but I would expect a bbappend to our recipes not an external layer.

[mhazley]

but this seems to include more things

Sorry, I completely missed that!

[Jessseee]

I am quite new to working with yocto, so I am not quite sure what the best approach is. However, my idea was that because the dts file is completely missing from Kernel 5.10 it has to be externally added.

[agherzan]

That makes sense @Jessseee. I think the best would be to introduce it in the kernel recipes we have in the layer - linux-raspberrypi ones.

[mhazley]

@Jessseee I think you can just make your bbappend for the dts recipes-kernel/linux/linux-raspberrypi_%.bbappend and it will apply the append to both the 5.10 and the 5.15 recipes.

I am quite new to yocto too, but I patched a dtoverlay in a similar way in BalenaOS once.

[Jessseee]

@mhazley The problem is that the devicetree files should only be added to linux-raspberrypi-dev and raspberrypi-5.10, because I think you will run into issues with 5.15 as it already has these files. As @agherzan said, they need to be added directly to the kernel recipes. Also, I found out that apparently the devicetree layer also needs a dtsi file.

[ScottGibb]

@agherzan Is there any update on this approved? Also thank you for doing the work and adding it to the meta-raspberrypi layer!

[agherzan]

@Jessseee This looks good. One last request: can you please squash "imx708: Add compatibility layer " into "recipe-bsp: Add support for Raspberry Pi Camera Module v3". They make sense as one commit. Otherwise, I think we are good to go.

[Jessseee]

I squashed the commits and updated the branch.

[compiaffe]

What is the next step to get this merged in? @agherzan @Jessseee