Re: [PATCH] dt-bindings: firmware: cznic,turris-mox-rwtm: convert to DT schema

[Gabor Juhos]

Hi Krzysztof,

2026. 02. 21. 19:31 keltezéssel, Krzysztof Kozlowski írta:
> On 21/02/2026 19:21, Gabor Juhos wrote:
>> +
>> +description: |
>> +  This device tree node should be used on Turris Mox, or potentially
>> +  another A3700 compatible device running the Mox's rWTM firmware in
>> +  the secure processor (for example it is possible to flash this
>> +  firmware into EspressoBin).
>> +
>> +properties:
>> +  compatible:
>> +    oneOf:
>> +      - const: marvell,armada-3700-rwtm-firmware
>> +
>> +      - items:
>> +        - const: marvell,armada-3700-rwtm-firmware
> 
> This makes little sense. How this can be alone and followed by fallback?

I admit that this is quite messy, but let me describe the current situation in
detail.

Originally both the dt-bindings documentation and the 'turris-mox-rwtm' driver
have used the 'cznic,turris-mox-rwtm' compatible alone.

In commit 90ae47215de3 ("firmware: turris-mox-rwtm: add
marvell,armada-3700-rwtm-firmware compatible string") a new compatible string
'marvell,armada-3700-rwtm-firmware' has been added to the driver.

Additionally, in commit 3a52a48973b3 ("arm64: dts: marvell: armada-37xx: move
firmware node to generic dtsi file") added a node to the Armada 37xx SoC dtsi
file which uses only 'marvell,armada-3700-rwtm-firmware' as compatible. In the
same commit the 'armada-3720-turris-mox.dts' file has been modified to use both
compatible strings, and the 'cznic,turris-mox-rwtm'  has been chosen to be the
fallback.

Unfortunately, none of the commits above updated the original dt-binding
documentation, so it is out of date since more than 4 years.

In short, the driver handles both compatibles equally, none of those are a
fallback of the other one. And in the existing in-kernel dts files, the
compatible is specified in the following forms:
  "marvell,armada-3700-rwtm-firmware", "cznic,turris-mox-rwtm"
or
  "marvell,armada-3700-rwtm-firmware" alone

The dt-schema is based on these facts in order to avoid new 'dtbs_check'
warnings, even if this is not the optimal/best approach.

> Plus adding new compatible has to be explicit in commit msg, including
> the reason (existing users).
> 
>> +        - const: cznic,turris-mox-rwtm
> 
> Anyway, not tested. Please test your patches BEFORE you send them. I
> finished review here because of that.

Sorry about wasting your time. This is my first schema and I have missed the
'yamllint' warning indicated by Rob's bot in the other mail.

Nevertheless, I have tested the patch before sending, along with several different
versions besides the current one.

Without the patch 'make dtbs_check' throws the following warnings:

  arch/arm64/boot/dts/marvell/armada-3720-atlas-v5.dtb: /firmware/armada-3700-rwtm: failed to match any schema with compatible: ['marvell,armada-3700-rwtm-firmware', 'cznic,turris-mox-rwtm']
  arch/arm64/boot/dts/marvell/armada-3720-atlas-v5.dtb: /firmware/armada-3700-rwtm: failed to match any schema with compatible: ['marvell,armada-3700-rwtm-firmware', 'cznic,turris-mox-rwtm']
  arch/arm64/boot/dts/marvell/armada-3720-db.dtb: /firmware/armada-3700-rwtm: failed to match any schema with compatible: ['marvell,armada-3700-rwtm-firmware']
  arch/arm64/boot/dts/marvell/armada-3720-eDPU.dtb: /firmware/armada-3700-rwtm: failed to match any schema with compatible: ['marvell,armada-3700-rwtm-firmware']
  arch/arm64/boot/dts/marvell/armada-3720-espressobin.dtb: /firmware/armada-3700-rwtm: failed to match any schema with compatible: ['marvell,armada-3700-rwtm-firmware']
  arch/arm64/boot/dts/marvell/armada-3720-espressobin-emmc.dtb: /firmware/armada-3700-rwtm: failed to match any schema with compatible: ['marvell,armada-3700-rwtm-firmware']
  arch/arm64/boot/dts/marvell/armada-3720-espressobin-ultra.dtb: /firmware/armada-3700-rwtm: failed to match any schema with compatible: ['marvell,armada-3700-rwtm-firmware']
  arch/arm64/boot/dts/marvell/armada-3720-espressobin-v7.dtb: /firmware/armada-3700-rwtm: failed to match any schema with compatible: ['marvell,armada-3700-rwtm-firmware']
  arch/arm64/boot/dts/marvell/armada-3720-espressobin-v7-emmc.dtb: /firmware/armada-3700-rwtm: failed to match any schema with compatible: ['marvell,armada-3700-rwtm-firmware']
  arch/arm64/boot/dts/marvell/armada-3720-gl-mv1000.dtb: /firmware/armada-3700-rwtm: failed to match any schema with compatible: ['marvell,armada-3700-rwtm-firmware']
  arch/arm64/boot/dts/marvell/armada-3720-turris-mox.dtb: /firmware/armada-3700-rwtm: failed to match any schema with compatible: ['marvell,armada-3700-rwtm-firmware', 'cznic,turris-mox-rwtm']
  arch/arm64/boot/dts/marvell/armada-3720-turris-mox.dtb: /firmware/armada-3700-rwtm: failed to match any schema with compatible: ['marvell,armada-3700-rwtm-firmware', 'cznic,turris-mox-rwtm']
  arch/arm64/boot/dts/marvell/armada-3720-uDPU.dtb: /firmware/armada-3700-rwtm: failed to match any schema with compatible: ['marvell,armada-3700-rwtm-firmware']

Below are the results of testing different compatible rules.

  properties:
    compatible:
      const: cznic,turris-mox-rwtm

  arch/arm64/boot/dts/marvell/armada-3720-atlas-v5.dtb: armada-3700-rwtm (marvell,armada-3700-rwtm-firmware): compatible:0: 'cznic,turris-mox-rwtm' was expected
  arch/arm64/boot/dts/marvell/armada-3720-atlas-v5.dtb: armada-3700-rwtm (marvell,armada-3700-rwtm-firmware): compatible: ['marvell,armada-3700-rwtm-firmware', 'cznic,turris-mox-rwtm'] is too long
  arch/arm64/boot/dts/marvell/armada-3720-turris-mox.dtb: armada-3700-rwtm (marvell,armada-3700-rwtm-firmware): compatible:0: 'cznic,turris-mox-rwtm' was expected
  arch/arm64/boot/dts/marvell/armada-3720-turris-mox.dtb: armada-3700-rwtm (marvell,armada-3700-rwtm-firmware): compatible: ['marvell,armada-3700-rwtm-firmware', 'cznic,turris-mox-rwtm'] is too long

  properties:
    compatible:
      const: marvell,armada-3700-rwtm-firmware

  arch/arm64/boot/dts/marvell/armada-3720-atlas-v5.dtb: armada-3700-rwtm (marvell,armada-3700-rwtm-firmware): compatible: ['marvell,armada-3700-rwtm-firmware', 'cznic,turris-mox-rwtm'] is too long
  arch/arm64/boot/dts/marvell/armada-3720-turris-mox.dtb: armada-3700-rwtm (marvell,armada-3700-rwtm-firmware): compatible: ['marvell,armada-3700-rwtm-firmware', 'cznic,turris-mox-rwtm'] is too long

  properties:
    compatible:
      enum:
        - marvell,armada-3700-rwtm-firmware
        - cznic,turris-mox-rwtm

  arch/arm64/boot/dts/marvell/armada-3720-atlas-v5.dtb: armada-3700-rwtm (marvell,armada-3700-rwtm-firmware): compatible: ['marvell,armada-3700-rwtm-firmware', 'cznic,turris-mox-rwtm'] is too long
  arch/arm64/boot/dts/marvell/armada-3720-turris-mox.dtb: armada-3700-rwtm (marvell,armada-3700-rwtm-firmware): compatible: ['marvell,armada-3700-rwtm-firmware', 'cznic,turris-mox-rwtm'] is too long

  properties:
    compatible:
      items:
        - const: marvell,armada-3700-rwtm-firmware
        - const: cznic,turris-mox-rwtm

  arch/arm64/boot/dts/marvell/armada-3720-db.dtb: armada-3700-rwtm (marvell,armada-3700-rwtm-firmware): compatible: ['marvell,armada-3700-rwtm-firmware'] is too short
  arch/arm64/boot/dts/marvell/armada-3720-eDPU.dtb: armada-3700-rwtm (marvell,armada-3700-rwtm-firmware): compatible: ['marvell,armada-3700-rwtm-firmware'] is too short
  arch/arm64/boot/dts/marvell/armada-3720-espressobin-emmc.dtb: armada-3700-rwtm (marvell,armada-3700-rwtm-firmware): compatible: ['marvell,armada-3700-rwtm-firmware'] is too short
  arch/arm64/boot/dts/marvell/armada-3720-espressobin-ultra.dtb: armada-3700-rwtm (marvell,armada-3700-rwtm-firmware): compatible: ['marvell,armada-3700-rwtm-firmware'] is too short
  arch/arm64/boot/dts/marvell/armada-3720-espressobin-v7-emmc.dtb: armada-3700-rwtm (marvell,armada-3700-rwtm-firmware): compatible: ['marvell,armada-3700-rwtm-firmware'] is too short
  arch/arm64/boot/dts/marvell/armada-3720-espressobin-v7.dtb: armada-3700-rwtm (marvell,armada-3700-rwtm-firmware): compatible: ['marvell,armada-3700-rwtm-firmware'] is too short
  arch/arm64/boot/dts/marvell/armada-3720-espressobin.dtb: armada-3700-rwtm (marvell,armada-3700-rwtm-firmware): compatible: ['marvell,armada-3700-rwtm-firmware'] is too short
  arch/arm64/boot/dts/marvell/armada-3720-gl-mv1000.dtb: armada-3700-rwtm (marvell,armada-3700-rwtm-firmware): compatible: ['marvell,armada-3700-rwtm-firmware'] is too short
  arch/arm64/boot/dts/marvell/armada-3720-uDPU.dtb: armada-3700-rwtm (marvell,armada-3700-rwtm-firmware): compatible: ['marvell,armada-3700-rwtm-firmware'] is too short


I wanted to get rid of all warnings, so I ended up with the current patch.

Do you have any suggestion about what would be the acceptable solution to clean
up the current mess?


Regards,
Gabor