On 08/12/2021 05:44, Christian Hewitt wrote:

quoted

On 8 Dec 2021, at 1:21 am, Rob Herring [off-list ref] wrote:

On Tue, Nov 30, 2021 at 06:05:16AM +0000, Christian Hewitt wrote:

quoted

Add board bindings for the Amediatech X96-AIR STB which ships with
model variants distiguished by Ethernet configuration: models using
internal 10/100 PHY have a -100 suffix, while models using external
Gigabit PHY have a -1000 suffix.

Isn't the phy described in DT? Why do you need to describe this 1 
difference at the top level?

The difference is between internal VS external PHY, which means
difference in pinmuxing & settings for the MDIO mux selecting the
PHY interface.

The other issue is about the bootloader, the vendor bootloader is not
necessarily capable of detecting the PHY type, and correctly altering
the DT without a complex script.

Having a single DT adds a dependency on the bootloader, which for me isn't
acceptable.

Neil

Users who purchase Android STBs as a cheap Linux media device (or are
reimiaging an existing device when they give up on Android) generally
have no idea what a PHY is, so reading a device-tree file to pick the
correct one is beyond them. Most people blindly try all dtb files for
a class of device until they find one that works, so top-level naming
is simply to hint the process and reduce guesswork. It’s not perfect,
but it does appear to reduce the quantity of “Ethernet doesn’t work!”
posts seen in support forums.

Christian

quoted

quoted

Signed-off-by: Christian Hewitt <redacted>
---
Documentation/devicetree/bindings/arm/amlogic.yaml | 2 ++
1 file changed, 2 insertions(+)

diff --git a/Documentation/devicetree/bindings/arm/amlogic.yaml b/Documentation/devicetree/bindings/arm/amlogic.yaml
index 36081734f720..e9ab0ffe8be7 100644
--- a/Documentation/devicetree/bindings/arm/amlogic.yaml
+++ b/Documentation/devicetree/bindings/arm/amlogic.yaml

@@ -170,6 +170,8 @@ properties:
      - description: Boards with the Amlogic Meson SM1 S905X3/D3/Y3 SoC
        items:
          - enum:
+              - amediatech,x96-air-100
+              - amediatech,x96-air-1000
              - bananapi,bpi-m5
              - hardkernel,odroid-c4
              - hardkernel,odroid-hc4

-- 
2.17.1