How to use meta-adi with a board not in the list of supported boards

Question

The meta-adi Yocto layers at meta-adi-xilinx and meta-adi-core advertise that they will provide a highly customized Analog Devices kernel for use with PetaLinux. 
 I have two different boards that are *not* listed in the table of supported Projects/Devicetrees in the README.md at meta-adi-xilinx. However we have our own Vivado 2021.2 HDL design based on the Analog Devices spi-engine and dmac framework for both ADCs and DACs. 
 I am having trouble understanding why meta-adi only supports a small list of known device trees. I also don't understand the section "Adding a new Devicetree" in README.md . 
 
 Why would I need to delete *any* device tree nodes to use meta-adi? I'm going to want to use them! 
 Perhaps I don't understand the purpose of meta-adi. Isn't it providing the kernel patches to support the enhanced IIO subsystem to support various Analog Devices device drivers with the HDL spi-engine framework for performance? 
 Why would kernel enhancements be specific to a set of known device trees? 
 
 Can anyone clarify this?

nsa · Accepted Answer

ddickerhoof said: I'm just not understanding why there would be any "redefinition" of device tree nodes. The Xilinx device tree generator should generate nodes for all the IP during petalinux-config --get-hw-description, and the device tree gets extended with more information to fully describe the various spi-engines, dmacs, DACs and ADCs interfaced by the FPGA (through a .dtsi). 
 Yes, but as I said... Did you looked at those nodes that are generated in the pl.dtsi file? They are useless and won't work with any of ADI drivers and likely with your custom drivers. Just look at the dt compatible string and you'll notice that the auto generator just puts some name that won't work with our drivers. On top of this there are properties missing or just wrong... Now if any of these nodes happens to have the same name as the ones used by ADI kernel (this happens in some of the projects we have in our kernel), the build would fail unless we delete them. And that is exactly what meta-adi is doing and why we have those pl-delete-nodes files for every project. Now you can say that we could just overwrite the complete devicetree with our own and ignore pl.dtsi. We din't went' that way because 1) we wanted to keep the typical petalinux flow and 2) because someone might want to use xilinx IPs for which the nodes will be correctly auto-generated and thus there's no need to delete them. So you can fine tune what you delete or not in these files. 
 ddickerhoof said: and I need to provide driver modules specific for my IP. Is this incorrect? 
 That's correct but you'll also have to define that custom HW in devicetree and I'm fairly sure that the auto-generated nodes petalinux will give you, will be wrong. 
 ddickerhoof said: So, are you saying that the "Adding a new Devicetree" section is meant for adding another supported devicetree/project for others to use? 
 Correct, that's how I would do it and the cleanest way... 
 ddickerhoof said: And that for my purposes, I can just include the meta-adi layers, and provide other customizations as necessary, without having to delete any device tree nodes? 
 As I said, you might get things working without deleting any nodes as long as there are no nodes with the same name. But you'll still have unnecessary nodes though... 
 Another thing that I might ask is, are you planning to reuse some ADI devicetree or do you intend to only use the ones present in petalinux? If you just want to use petalinux there's another option for you (though it is not supported in meta-adi but easy to add): 
 * You could just bypass the devicetree recipe in meta-adi and solely use the petalinux flow. For this, you would have to redefine a lot of things in system-user.dtsi to fix the wrong nodes in pl.dtsi which in my opinion is more cumbersome. But it might work better for you, not sure... 
 
 - Nuno S&aacute;

Electronic Design Services - PartnerZone

How to use meta-adi with a board not in the list of supported boards

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