On Thu, Oct 01, 2020 at 12:19:08PM +0200, Ahmad Fatoum wrote:

Hi,

On 10/1/20 9:32 AM, Krzysztof Kozlowski wrote:

quoted

On Thu, Oct 01, 2020 at 09:22:03AM +0200, Ahmad Fatoum wrote:

quoted

quoted

diff --git a/arch/arm/boot/dts/imx6dl-pico-hobbit.dts b/arch/arm/boot/dts/imx6dl-pico-hobbit.dts
index d7403c5c4337..08fedcbcc91b 100644
--- a/arch/arm/boot/dts/imx6dl-pico-hobbit.dts
+++ b/arch/arm/boot/dts/imx6dl-pico-hobbit.dts

@@ -13,5 +13,5 @@
 
 / {
 	model = "TechNexion PICO-IMX6 DualLite/Solo Board and Hobbit baseboard";
-	compatible = "technexion,imx6dl-pico", "fsl,imx6dl";
+	compatible = "technexion,imx6dl-pico-hobbit", "fsl,imx6dl";
 };

The bindings, added in commit 53b61224ca40 ("dt-bindings: arm: fsl: Add
TechNexion boards"), describe that these are the only valid compatibles.
"technexion,imx6dl-pico" is not valid and would require changing the
bindings, thus breaking compatibility which you want to avoid.> 
The bindings, not what is present in DTS, is considered ABI.

The existing binding doesn't cover these boards then and needs to be
extended, no? How about following patch?

What do you mean it doesn't cover? It was added exactly to handle them:
+              - technexion,imx6q-pico-dwarf   # TechNexion i.MX6Q Pico-Dwarf
+              - technexion,imx6q-pico-hobbit  # TechNexion i.MX6Q Pico-Hobbit
+              - technexion,imx6q-pico-nymph   # TechNexion i.MX6Q Pico-Nymph
+              - technexion,imx6q-pico-pi      # TechNexion i.MX6Q Pico-Pi

[I guess we need to keep the two-compatible list they were originally
 in for compatibility even if it's unused among upstream device trees?]

You want to change both the binding (thus breaking the ABI) and update
the DTS to reflect new ABI. Then why having a binding at all?

I would assume that either binding is correct or DTS. You propose that
both are wrong and both need changes... in such case this is clearly
broken.

Best regards,
Krzysztof

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