From: Greg KH <gregkh@linuxfoundation.org>
To: Ricardo Ribalda <ribalda@chromium.org>
Cc: linux-usb@vger.kernel.org, devicetree@vger.kernel.org,
Yunke Cao <yunkec@chromium.org>
Subject: Re: Annotating USB device Location in DT
Date: Thu, 12 Dec 2024 15:03:51 +0100 [thread overview]
Message-ID: <2024121204-underarm-last-97ae@gregkh> (raw)
In-Reply-To: <CANiDSCtZrWAbH14fqoSq9OKv8oV30Df6AnvWGCw3gdWHT3RBrw@mail.gmail.com>
On Thu, Dec 12, 2024 at 02:42:34PM +0100, Ricardo Ribalda wrote:
> Hi all,
>
> I'm working on a way to annotate the location of a USB device within a
> system, specifically whether it's "user-facing" or "world-facing."
>
> There's precedent for this type of annotation:
>
> - ACPI: Uses the '_PLD' property for this purpose
> (https://uefi.org/htmlspecs/ACPI_Spec_6_4_html/06_Device_Configuration/Device_Configuration.html#pld-physical-location-of-device).
> We already leverage this for MIPI camera sensors
> (https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/media/pci/intel/ipu-bridge.c#n265).
>
> - Device Tree : Has a property for this within
> video-interface-devices.yaml
> (https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/devicetree/bindings/media/video-interface-devices.yaml#n386).
>
> I propose adding a similar property to usb-device.yaml
> (https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/devicetree/bindings/usb/usb-device.yaml).
>
> The ultimate goal is to have this information consumed by the video
> driver and exposed to userspace via the V4L2_CID_CAMERA_ORIENTATION
> control (https://www.kernel.org/doc/html/latest/userspace-api/media/v4l/ext-ctrls-camera.html).
>
> What do you think about this?
I think you should copy what ACPI does here, as long as it doesn't
conflict with the existing video-interface-devices.yaml definition.
Will that work?
thanks,
greg k-h
next prev parent reply other threads:[~2024-12-12 14:03 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-12-12 13:42 Annotating USB device Location in DT Ricardo Ribalda
2024-12-12 14:03 ` Greg KH [this message]
2024-12-12 15:15 ` Alan Stern
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