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@chromium.org>
---
.../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@chromium.org>
+
+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
+
+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@vger.kernel.org
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-googOn 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@chromium.org>
> ---
> .../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@chromium.org>
> +
> +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?
> +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@vger.kernel.org
> 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
>
Hi Conor
On Fri, 26 Sept 2025 at 18:55, Conor Dooley <conor@kernel.org> 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@chromium.org>
> > ---
> > .../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@chromium.org>
> > +
> > +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@kernel.org/:
```
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@vger.kernel.org
> > 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
On Mon, Sep 29, 2025 at 10:30:35AM +0200, Ricardo Ribalda wrote:
> Hi Conor
>
> On Fri, 26 Sept 2025 at 18:55, Conor Dooley <conor@kernel.org> 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@chromium.org>
> > > ---
> > > .../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@chromium.org>
> > > +
> > > +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@kernel.org/:
> ```
> 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 :)
It'd work, I think, if you permitted the pattern from usb-device as a
fallback compatible. I don't know if that would work for whatever niche
you're attempting to fill here though.
Probably a Rob question ultimately.
>
> 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@vger.kernel.org
> > > 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
>
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