diff mbox series

[RFC,v2,6/7] dt-bindings: arm: mediatek: Remove SKU specific compatibles for Google Krane

Message ID 20231109100606.1245545-7-wenst@chromium.org
State New
Headers show
Series of: Introduce hardware prober driver | expand

Commit Message

Chen-Yu Tsai Nov. 9, 2023, 10:06 a.m. UTC
In cases where the same Chromebook model is manufactured with different
components (MIPI DSI panels, MIPI CSI camera sensors, or trackpad /
touchscreens with conflicting addresses), a different SKU ID is
allocated to each specific combination. This SKU ID is exported by the
bootloader into the device tree, and can be used to "discover" which
combination is present on the current machine. Thus we no longer have
to specify separate compatible strings for each of them.

Remove the SKU specific compatible strings for Google Krane.

Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
---
 Documentation/devicetree/bindings/arm/mediatek.yaml | 3 ---
 1 file changed, 3 deletions(-)

Comments

Rob Herring Nov. 10, 2023, 9:04 p.m. UTC | #1
On Thu, Nov 09, 2023 at 06:06:03PM +0800, Chen-Yu Tsai wrote:
> In cases where the same Chromebook model is manufactured with different
> components (MIPI DSI panels, MIPI CSI camera sensors, or trackpad /
> touchscreens with conflicting addresses), a different SKU ID is
> allocated to each specific combination. This SKU ID is exported by the
> bootloader into the device tree, and can be used to "discover" which
> combination is present on the current machine. Thus we no longer have
> to specify separate compatible strings for each of them.

You just broke an existing kernel with a new DT having this change.

Just because you come up with a new way to do things, doesn't mean you 
can remove the old way.

> 
> Remove the SKU specific compatible strings for Google Krane.
> 
> Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
> ---
>  Documentation/devicetree/bindings/arm/mediatek.yaml | 3 ---
>  1 file changed, 3 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/arm/mediatek.yaml b/Documentation/devicetree/bindings/arm/mediatek.yaml
> index a4541855a838..ef3dfb286814 100644
> --- a/Documentation/devicetree/bindings/arm/mediatek.yaml
> +++ b/Documentation/devicetree/bindings/arm/mediatek.yaml
> @@ -186,9 +186,6 @@ properties:
>            - const: mediatek,mt8183
>        - description: Google Krane (Lenovo IdeaPad Duet, 10e,...)
>          items:
> -          - enum:
> -              - google,krane-sku0
> -              - google,krane-sku176
>            - const: google,krane
>            - const: mediatek,mt8183
>        - description: Google Willow (Acer Chromebook 311 C722/C722T)
> -- 
> 2.42.0.869.gea05f2083d-goog
>
Doug Anderson Nov. 11, 2023, 12:29 a.m. UTC | #2
Hi,

On Fri, Nov 10, 2023 at 1:04 PM Rob Herring <robh@kernel.org> wrote:
>
> On Thu, Nov 09, 2023 at 06:06:03PM +0800, Chen-Yu Tsai wrote:
> > In cases where the same Chromebook model is manufactured with different
> > components (MIPI DSI panels, MIPI CSI camera sensors, or trackpad /
> > touchscreens with conflicting addresses), a different SKU ID is
> > allocated to each specific combination. This SKU ID is exported by the
> > bootloader into the device tree, and can be used to "discover" which
> > combination is present on the current machine. Thus we no longer have
> > to specify separate compatible strings for each of them.
>
> You just broke an existing kernel with a new DT having this change.
>
> Just because you come up with a new way to do things, doesn't mean you
> can remove the old way.

I was wondering about that, actually. My understanding was that what
Chen-Yu was doing here was correct, but I'm happy to be educated.

Specifically, I think that after his series old device trees will
continue to boot just fine. ...so if someone took a device tree from
before his series and booted it on a kernel after his series that
everything would be hunky dory. If that doesn't work then, I agree,
that should be fixed.

However, here, he is documenting what the "latest and greatest" device
tree should look at and that matches what's checked into the "dts"
directory. In general, I thought that yaml files didn't necessarily
always document old/deprecated ways of doing things and just focused
on documenting the new/best way.

Now, obviously, if someone took a new device tree and tried to put it
on an old kernel then it wouldn't work, but I was always under the
impression that wasn't a requirement.


-Doug
diff mbox series

Patch

diff --git a/Documentation/devicetree/bindings/arm/mediatek.yaml b/Documentation/devicetree/bindings/arm/mediatek.yaml
index a4541855a838..ef3dfb286814 100644
--- a/Documentation/devicetree/bindings/arm/mediatek.yaml
+++ b/Documentation/devicetree/bindings/arm/mediatek.yaml
@@ -186,9 +186,6 @@  properties:
           - const: mediatek,mt8183
       - description: Google Krane (Lenovo IdeaPad Duet, 10e,...)
         items:
-          - enum:
-              - google,krane-sku0
-              - google,krane-sku176
           - const: google,krane
           - const: mediatek,mt8183
       - description: Google Willow (Acer Chromebook 311 C722/C722T)