Re: [PATCH v2 2/5] dt-bindings: media: Add bindings for ARM mali-c55

From: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
To: Sakari Ailus <sakari.ailus@iki.fi>
Cc: Daniel Scally <dan.scally@ideasonboard.com>,
	linux-media@vger.kernel.org, devicetree@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	jacopo.mondi@ideasonboard.com, nayden.kanchev@arm.com,
	robh+dt@kernel.org, mchehab@kernel.org,
	krzysztof.kozlowski+dt@linaro.org, conor+dt@kernel.org,
	jerome.forissier@linaro.org, kieran.bingham@ideasonboard.com
Subject: Re: [PATCH v2 2/5] dt-bindings: media: Add bindings for ARM mali-c55
Date: Mon, 26 Feb 2024 14:58:18 +0200	[thread overview]
Message-ID: <20240226125818.GA26163@pendragon.ideasonboard.com> (raw)
In-Reply-To: <ZdyB_yHn9yImTuhm@valkosipuli.retiisi.eu>

On Mon, Feb 26, 2024 at 12:20:15PM +0000, Sakari Ailus wrote:
> On Mon, Feb 26, 2024 at 02:04:31PM +0200, Laurent Pinchart wrote:
> > On Mon, Feb 26, 2024 at 11:54:22AM +0000, Sakari Ailus wrote:
> > > On Wed, Feb 14, 2024 at 02:19:03PM +0000, Daniel Scally wrote:
> > > > Add the yaml binding for ARM's Mali-C55 Image Signal Processor.
> > > > 
> > > > Acked-by: Nayden Kanchev <nayden.kanchev@arm.com>
> > > > Signed-off-by: Daniel Scally <dan.scally@ideasonboard.com>
> > > > ---
> > > > Changes in v2:
> > > > 
> > > > 	- Added clocks information
> > > > 	- Fixed the warnings raised by Rob
> > > > 
> > > >  .../bindings/media/arm,mali-c55.yaml          | 77 +++++++++++++++++++
> > > >  1 file changed, 77 insertions(+)
> > > >  create mode 100644 Documentation/devicetree/bindings/media/arm,mali-c55.yaml
> > > > 
> > > > diff --git a/Documentation/devicetree/bindings/media/arm,mali-c55.yaml b/Documentation/devicetree/bindings/media/arm,mali-c55.yaml
> > > > new file mode 100644
> > > > index 000000000000..30038cfec3a4
> > > > --- /dev/null
> > > > +++ b/Documentation/devicetree/bindings/media/arm,mali-c55.yaml
> > > > @@ -0,0 +1,77 @@
> > > > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> > > > +%YAML 1.2
> > > > +---
> > > > +$id: http://devicetree.org/schemas/media/arm,mali-c55.yaml#
> > > > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > > > +
> > > > +title: ARM Mali-C55 Image Signal Processor
> > > > +
> > > > +maintainers:
> > > > +  - Daniel Scally <dan.scally@ideasonboard.com>
> > > > +  - Jacopo Mondi <jacopo.mondi@ideasonboard.com>
> > > > +
> > > > +properties:
> > > > +  compatible:
> > > > +    const: arm,mali-c55
> > > > +
> > > > +  reg:
> > > > +    maxItems: 1
> > > > +
> > > > +  interrupts:
> > > > +    maxItems: 1
> > > > +
> > > > +  clocks:
> > > > +    items:
> > > > +      - description: ISP video clock
> > > > +      - description: ISP AXI clock
> > > > +      - description: ISP AHB-lite clock
> > > > +
> > > > +  clock-names:
> > > > +    items:
> > > > +      - const: vclk
> > > > +      - const: aclk
> > > > +      - const: hclk
> > > > +
> > > > +  ports:
> > > > +    $ref: /schemas/graph.yaml#/properties/ports
> > > > +
> > > > +    properties:
> > > > +      port@0:
> > > > +        $ref: /schemas/graph.yaml#/properties/port

Adding

        description: Input parallel video bus

here would be useful.

> > > > +
> > > > +        properties:
> > > > +          endpoint:
> > > > +            $ref: /schemas/graph.yaml#/properties/endpoint
> > > > +
> > > > +required:
> > > > +  - compatible
> > > > +  - reg
> > > > +  - interrupts
> > > > +  - clocks
> > > > +  - clock-names
> > > > +  - ports
> > > > +
> > > > +additionalProperties: false
> > > > +
> > > > +examples:
> > > > +  - |
> > > > +    mali_c55: isp@400000 {
> > > > +      compatible = "arm,mali-c55";
> > > > +      reg = <0x400000 0x200000>;
> > > > +      clocks = <&clk 0>, <&clk 1>, <&clk 2>;
> > > > +      clock-names = "vclk", "aclk", "hclk";
> > > > +      interrupts = <0>;
> > > > +
> > > > +      ports {
> > > > +        #address-cells = <1>;
> > > > +        #size-cells = <0>;
> > > > +
> > > > +        port@0 {
> > > > +          reg = <0>;
> > > > +          isp_in: endpoint {
> > > > +              remote-endpoint = <&mipi_out>;
> > > 
> > > I suppose this is a CSI-2 interface with D-PHY?
> > 
> > No, that's an internal parallel bus. Depending on the SoC integration,
> > it can be connected to a CSI-2 receiver, a DMA engine, or a mux to
> > select between different sources.
> 
> The name suggests otherwise. Maybe change that to something more
> descriptive?

We could rename mipi_out to csi2_rx_out, sure.

> > > How many lanes do you have and is lane remapping / polarity inversion
> > > supported?
> > > 
> > > This should be reflected in bindings.
> > > 
> > > > +          };
> > > > +        };
> > > > +      };
> > > > +    };
> > > > +...

-- 
Regards,

Laurent Pinchart

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