Re: (EXT) [RFC PATCH v4 03/12] dt-bindings: media: Add bindings for bcm2835-unicam

From: Alexander Stein
Date: Fri Feb 04 2022 - 03:50:16 EST


Am Donnerstag, 3. Februar 2022, 18:50:00 CET schrieb Jean-Michel Hautbois:
> Introduce the dt-bindings documentation for bcm2835 CCP2/CSI2 Unicam
> camera interface. Also add a MAINTAINERS entry for it.
>
> Signed-off-by: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx>
> Signed-off-by: Naushir Patuck <naush@xxxxxxxxxxxxxxx>
> Signed-off-by: Jean-Michel Hautbois <jeanmichel.hautbois@xxxxxxxxxxxxxxxx>
>
> ---
> v4:
> - make MAINTAINERS its own patch
> - describe the reg and clocks correctly
> - use a vendor entry for the number of data lanes
> ---
> .../bindings/media/brcm,bcm2835-unicam.yaml | 110 ++++++++++++++++++
> 1 file changed, 110 insertions(+)
> create mode 100644
> Documentation/devicetree/bindings/media/brcm,bcm2835-unicam.yaml
>
> diff --git
> a/Documentation/devicetree/bindings/media/brcm,bcm2835-unicam.yaml
> b/Documentation/devicetree/bindings/media/brcm,bcm2835-unicam.yaml new file
> mode 100644
> index 000000000000..0725a0267c60
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/media/brcm,bcm2835-unicam.yaml
> @@ -0,0 +1,110 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/media/brcm,bcm2835-unicam.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Broadcom BCM283x Camera Interface (Unicam)
> +
> +maintainers:
> + - Raspberry Pi Kernel Maintenance <kernel-list@xxxxxxxxxxxxxxx>
> +
> +description: |-
> + The Unicam block on BCM283x SoCs is the receiver for either
> + CSI-2 or CCP2 data from image sensors or similar devices.
> +
> + The main platform using this SoC is the Raspberry Pi family of boards.
> + On the Pi the VideoCore firmware can also control this hardware block,
> + and driving it from two different processors will cause issues.
> + To avoid this, the firmware checks the device tree configuration
> + during boot. If it finds device tree nodes starting by csi then
> + it will stop the firmware accessing the block, and it can then
> + safely be used via the device tree binding.
> +
> +properties:
> + compatible:
> + const: brcm,bcm2835-unicam
> +
> + reg:
> + items:
> + - description: Unicam block.
> + - description: Clock Manager Image (CMI) block.
> +
> + interrupts:
> + maxItems: 1
> +
> + clocks:
> + items:
> + - description: Clock to drive the LP state machine of Unicam.
> + - description: Clock for the vpu (core clock).
> +
> + clock-names:
> + items:
> + - const: lp
> + - const: vpu
> +
> + power-domains:
> + items:
> + - description: Unicam power domain
> +
> + brcm,num-data-lanes:
> + $ref: /schemas/types.yaml#/definitions/uint32
> + enum: [ 2, 4 ]
> + description: Number of data lanes on the csi bus

There is already data-lanes in Documentation/devicetree/bindings/media/video-
interfaces.yaml. AFAICS these two are identical. Can't the video-
interface.yaml be used for this? I'm no expert TBH.

Regards,
Alexander