Re: [PATCH v5 03/11] dt-bindings: media: Add bindings for bcm2835-unicam

Sakari Ailus
2022-02-25T08:28:07Z

Hi Jean-Michel,

On Tue, Feb 08, 2022 at 04:50:19PM +0100, Jean-Michel Hautbois wrote:
> Introduce the dt-bindings documentation for bcm2835 CCP2/CSI2 Unicam
> camera interface.
>
> Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
> Signed-off-by: Naushir Patuck <naush@raspberrypi.com>
> Signed-off-by: Jean-Michel Hautbois <jeanmichel.hautbois@ideasonboard.com>
> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
>
> ---
> 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 | 117 ++++++++++++++++++
> 1 file changed, 117 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..1938ace23b3d
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/media/brcm,bcm2835-unicam.yaml
> @@ -0,0 +1,117 @@
> +# 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@raspberrypi.com>
> +
> +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 whose name starts with '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.
> +
> + reg-names:
> + items:
> + - const: unicam
> + - const: cmi
> +
> + 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 CSI-2 data lanes supported by this Unicam instance. The number
> + of data lanes actively used is specified with the data-lanes endpoint
> + property.
> +
> + port:
> + $ref: /schemas/graph.yaml#/$defs/port-base
> + unevaluatedProperties: false
> +
> + properties:
> + endpoint:
> + $ref: /schemas/media/video-interfaces.yaml#
> + unevaluatedProperties: false
> +
> + properties:
> + data-lanes: true
> +
> + required:
> + - data-lanes

As you support both CSI-2 D-PHY and CCP, you'll need bus-type (or make
CSI-2 default), and optionally strobe property with CCP.

> +
> + required:
> + - endpoint
> +
> +required:
> + - compatible
> + - reg
> + - reg-names
> + - interrupts
> + - clocks
> + - clock-names
> + - power-domains
> + - brcm,num-data-lanes
> + - port
> +
> +additionalProperties: False
> +
> +examples:
> + - |
> + #include <dt-bindings/clock/bcm2835.h>
> + #include <dt-bindings/interrupt-controller/arm-gic.h>
> + #include <dt-bindings/power/raspberrypi-power.h>
> + csi1: csi@7e801000 {
> + compatible = "brcm,bcm2835-unicam";
> + reg = <0x7e801000 0x800>,
> + <0x7e802004 0x4>;
> + reg-names = "unicam", "cmi";
> + interrupts = <GIC_SPI 103 IRQ_TYPE_LEVEL_HIGH>;
> + clocks = <&clocks BCM2835_CLOCK_CAM1>,
> + <&firmware_clocks 4>;
> + clock-names = "lp", "vpu";
> + power-domains = <&power RPI_POWER_DOMAIN_UNICAM1>;
> + brcm,num-data-lanes = <2>;
> + port {
> + csi1_ep: endpoint {
> + remote-endpoint = <&imx219_0>;
> + data-lanes = <1 2>;
> + };
> + };
> + };
> +...

--
Kind regards,

Sakari Ailus