[PATCH] dt-bindings: usb: usb-device: allow multiple compatibles

[Quentin Schulz]

From: Quentin Schulz <quentin.schulz@xxxxxxxxx>

The dt-core typically allows multiple compatibles[1] but usb-device
currently forces a single compatible.

This is an issue when multiple devices with slightly different productID
all behave the same. This would require the driver to keep updating its
compatible matching table and the bindings to include this new productID
instead of doing what is usually done: have two compatibles, the
leftmost which matches exactly the HW device definition, and the
rightmost one as a fallback which is assumed to be 100% compatible with
the device at hand. If this assumption turns out to be wrong, it is easy
to work around this without having to modify the device tree by handling
the leftmost compatible in the driver.

[1] https://github.com/devicetree-org/dt-schema/blob/main/dtschema/schemas/dt-core.yaml#L21-L25

Signed-off-by: Quentin Schulz <quentin.schulz@xxxxxxxxx>
---
This came up while working on fixing USB on an RK3399 Puma which has an
onboard USB hub whose productID isn't in any driver compatible list
but which can be supported by a driver with a slightly different
productID matching another variant of the same IC, from the same
datasheet.

See https://lore.kernel.org/linux-rockchip/20250326-onboard_usb_dev-v1-0-a4b0a5d1b32c@xxxxxxxxxxxxx/
---
 Documentation/devicetree/bindings/usb/usb-device.yaml | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/usb/usb-device.yaml b/Documentation/devicetree/bindings/usb/usb-device.yaml
index c676956810331b81f11f3624340fc3e612c98315..9d55be4fb5981164cca969dbda5ba70ab3a87773 100644
--- a/Documentation/devicetree/bindings/usb/usb-device.yaml
+++ b/Documentation/devicetree/bindings/usb/usb-device.yaml
@@ -28,7 +28,8 @@ description: |
 
 properties:
   compatible:
-    pattern: "^usb[0-9a-f]{1,4},[0-9a-f]{1,4}$"
+    items:
+      pattern: "^usb[0-9a-f]{1,4},[0-9a-f]{1,4}$"
     description: Device nodes or combined nodes.
       "usbVID,PID", where VID is the vendor id and PID the product id.
       The textual representation of VID and PID shall be in lower case

---
base-commit: 834a4a689699090a406d1662b03affa8b155d025
change-id: 20250415-dt-binding-usb-device-compatibles-188f7b0a81b4

Best regards,
-- 
Quentin Schulz <quentin.schulz@xxxxxxxxx>