Re: [PATCH v3 07/12] dt-bindings: media: Add usb-camera-module
From: Ricardo Ribalda
Date: Mon Sep 29 2025 - 04:30:51 EST
Hi Conor
On Fri, 26 Sept 2025 at 18:55, Conor Dooley <conor@xxxxxxxxxx> wrote:
>
> On Fri, Sep 26, 2025 at 01:11:31PM +0000, Ricardo Ribalda wrote:
> > For fixed cameras modules the OS needs to know where they are mounted.
> > This information is used to determine if images need to be rotated or
> > not.
> >
> > ACPI has a property for this purpose, which is parsed by
> > acpi_get_physical_device_location():
> > https://uefi.org/htmlspecs/ACPI_Spec_6_4_html/06_Device_Configuration/Device_Configuration.html#pld-physical-location-of-device
> >
> > In DT we have similar properties for video-interface-devices called
> > orientation and rotation:
> > Documentation/devicetree/bindings/media/video-interface-devices.yaml
> >
> > Add a new schema that combines usb/usb-device.yaml and
> > media/video-interface-devices.yaml
> >
> > Signed-off-by: Ricardo Ribalda <ribalda@xxxxxxxxxxxx>
> > ---
> > .../bindings/media/usb-camera-module.yaml | 46 ++++++++++++++++++++++
> > MAINTAINERS | 1 +
> > 2 files changed, 47 insertions(+)
> >
> > diff --git a/Documentation/devicetree/bindings/media/usb-camera-module.yaml b/Documentation/devicetree/bindings/media/usb-camera-module.yaml
> > new file mode 100644
> > index 0000000000000000000000000000000000000000..e4ad6f557b9151751522e49b72ae6584deb0c7ba
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/media/usb-camera-module.yaml
> > @@ -0,0 +1,46 @@
> > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/media/usb-camera-module.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: USB Camera Module
> > +
> > +maintainers:
> > + - Ricardo Ribalda <ribalda@xxxxxxxxxxxx>
> > +
> > +description: |
> > + This schema allows for annotating auxiliary information for fixed camera
> > + modules. This information enables the system to determine if incoming frames
> > + require rotation, mirroring, or other transformations. It also describes the
> > + module's relationship with other hardware elements, such as flash LEDs or
> > + Voice Coil Motors (VCMs).
> > +
> > +allOf:
> > + - $ref: /schemas/usb/usb-device.yaml#
> > + - $ref: /schemas/media/video-interface-devices.yaml#
> > +
> > +properties:
> > + reg:
> > + maxItems: 1
> > +
>
> What actually causes this schema to be applied? Did I miss it getting
> included somewhere?
I guess your question is why I have not defined the compatible field?
I tried this change[1] with no luck:
/usr/local/google/home/ribalda/work/linux/Documentation/devicetree/bindings/media/uvc-camera.example.dtb:
device@1 (uvc-camera): compatible: ['uvc-camera'] does not contain
items matching the given schema
I think it failed, because If we add these allOfs as Rob proposed
https://lore.kernel.org/all/20250625185608.GA2010256-robh@xxxxxxxxxx/:
```
allOf:
- $ref: /schemas/usb/usb-device.yaml#
- $ref: /schemas/media/video-interface-devices.yaml#
```
We cannot (or I do not know how to) have a different compatible than
the one from usb-device.yaml
Any suggestion on how to do this properly will be highly appreciated :)
Thanks!
[1]
@@ -21,10 +21,14 @@ allOf:
- $ref: /schemas/media/video-interface-devices.yaml#
properties:
+ compatible:
+ const: uvc-camera
+
reg:
maxItems: 1
required:
+ - compatible
- reg
additionalProperties: true
@@ -38,8 +42,8 @@ examples:
#size-cells = <0>;
device@1 {
- compatible = "usb123,4567";
+ compatible = "uvc-camera";
reg = <2>;
orientation = <0>;
rotation = <90>;
};
>
> > +required:
> > + - reg
> > +
> > +additionalProperties: true
> > +
> > +examples:
> > + - |
> > + usb@11270000 {
> > + reg = <0x11270000 0x1000>;
> > + interrupts = <0x0 0x4e 0x0>;
> > + #address-cells = <1>;
> > + #size-cells = <0>;
> > +
> > + device@1 {
> > + compatible = "usb123,4567";
> > + reg = <2>;
> > + orientation = <0>;
> > + rotation = <90>;
> > + };
> > + };
> > diff --git a/MAINTAINERS b/MAINTAINERS
> > index ee8cb2db483f6a5e96b62b6f2edd05b1427b69f5..1503502a3aed2625e8ff488456ccd7305cc74ba7 100644
> > --- a/MAINTAINERS
> > +++ b/MAINTAINERS
> > @@ -26258,6 +26258,7 @@ L: linux-media@xxxxxxxxxxxxxxx
> > S: Maintained
> > W: http://www.ideasonboard.org/uvc/
> > T: git git://linuxtv.org/media.git
> > +F: Documentation/devicetree/bindings/media/usb-camera-module.yaml
> > F: Documentation/userspace-api/media/drivers/uvcvideo.rst
> > F: Documentation/userspace-api/media/v4l/metafmt-uvc-msxu-1-5.rst
> > F: Documentation/userspace-api/media/v4l/metafmt-uvc.rst
> >
> > --
> > 2.51.0.536.g15c5d4f767-goog
> >
--
Ricardo Ribalda