linux-kernel - Re: [RFC PATCH v9 5/9] dt-binding: tegra: Add VI and CSI bindings

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Message-ID: <20200422172047.GA18765@pendragon.ideasonboard.com>
Date:   Wed, 22 Apr 2020 20:20:47 +0300
From:   Laurent Pinchart <laurent.pinchart@...asonboard.com>
To:     Sowjanya Komatineni <skomatineni@...dia.com>
Cc:     thierry.reding@...il.com, jonathanh@...dia.com, frankc@...dia.com,
        hverkuil@...all.nl, sakari.ailus@....fi, helen.koike@...labora.com,
        digetx@...il.com, sboyd@...nel.org, linux-media@...r.kernel.org,
        devicetree@...r.kernel.org, linux-clk@...r.kernel.org,
        linux-tegra@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [RFC PATCH v9 5/9] dt-binding: tegra: Add VI and CSI bindings

Hi Sowjanya,

Thank you for the patch.

On Tue, Apr 21, 2020 at 11:18:55PM -0700, Sowjanya Komatineni wrote:
> Tegra contains VI controller which can support up to 6 MIPI CSI
> camera sensors.
> 
> Each Tegra CSI port from CSI unit can be one-to-one mapper to
> VI channel and can capture from an external camera sensor or
> from built-in test pattern generator.
> 
> This patch adds dt-bindings for Tegra VI and CSI.
> 
> Acked-by: Thierry Reding <treding@...dia.com>
> Reviewed-by: Rob Herring <robh@...nel.org>
> Signed-off-by: Sowjanya Komatineni <skomatineni@...dia.com>
> ---
>  .../display/tegra/nvidia,tegra20-host1x.txt        | 73 ++++++++++++++++++----
>  1 file changed, 60 insertions(+), 13 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/display/tegra/nvidia,tegra20-host1x.txt b/Documentation/devicetree/bindings/display/tegra/nvidia,tegra20-host1x.txt
> index 9999255..4731921 100644
> --- a/Documentation/devicetree/bindings/display/tegra/nvidia,tegra20-host1x.txt
> +++ b/Documentation/devicetree/bindings/display/tegra/nvidia,tegra20-host1x.txt
> @@ -40,14 +40,30 @@ of the following host1x client modules:
>  
>    Required properties:
>    - compatible: "nvidia,tegra<chip>-vi"
> -  - reg: Physical base address and length of the controller's registers.
> +  - reg: Physical base address and length of the controller registers.
>    - interrupts: The interrupt outputs from the controller.
> -  - clocks: Must contain one entry, for the module clock.
> +  - clocks: clocks: Must contain one entry, for the module clock.
>      See ../clocks/clock-bindings.txt for details.
> -  - resets: Must contain an entry for each entry in reset-names.
> -    See ../reset/reset.txt for details.
> -  - reset-names: Must include the following entries:
> -    - vi
> +  - Tegra20/Tegra30/Tegra114/Tegra124:
> +    - resets: Must contain an entry for each entry in reset-names.
> +      See ../reset/reset.txt for details.
> +    - reset-names: Must include the following entries:
> +      - vi
> +  - Tegra210:
> +    - power-domains: Must include venc powergate node as vi is in VE partition.
> +  - Tegra210 has CSI part of VI sharing same host interface and register space.
> +    So, VI device node should have CSI child node.
> +
> +    - csi: mipi csi interface to vi
> +
> +      Required properties:
> +      - compatible: "nvidia,tegra210-csi"
> +      - reg: Physical base address offset to parent and length of the controller
> +        registers.
> +      - clocks: Must contain entries csi, cilab, cilcd, cile, csi_tpg clocks.
> +        See ../clocks/clock-bindings.txt for details.
> +      - power-domains: Must include sor powergate node as csicil is in
> +        SOR partition.

A bit of a stupid question maybe, but why is this needed ? Can't the
driver that handles the vi DT node ("nvidia,tegra20-vi") handle all the
registers for all the sub-blocks ? Can't we move the clocks and power
domains from the CSI node to the VI node ?

Regardless of the answer to this question, I think this is missing port
nodes for the physical CSI-2 inputs, to connect them to sensors. I
haven't seen anywhere in this series how a CSI-2 sensor is linked to the
VI.

>  
>  - epp: encoder pre-processor
>  
> @@ -309,13 +325,44 @@ Example:
>  			reset-names = "mpe";
>  		};
>  
> -		vi {
> -			compatible = "nvidia,tegra20-vi";
> -			reg = <0x54080000 0x00040000>;
> -			interrupts = <0 69 0x04>;
> -			clocks = <&tegra_car TEGRA20_CLK_VI>;
> -			resets = <&tegra_car 100>;
> -			reset-names = "vi";
> +		vi@...80000 {
> +			compatible = "nvidia,tegra210-vi";
> +			reg = <0x0 0x54080000 0x0 0x700>;
> +			interrupts = <GIC_SPI 69 IRQ_TYPE_LEVEL_HIGH>;
> +			assigned-clocks = <&tegra_car TEGRA210_CLK_VI>;
> +			assigned-clock-parents = <&tegra_car TEGRA210_CLK_PLL_C4_OUT0>;
> +
> +			clocks = <&tegra_car TEGRA210_CLK_VI>;
> +			power-domains = <&pd_venc>;
> +
> +			#address-cells = <1>;
> +			#size-cells = <1>;
> +
> +			ranges = <0x0 0x0 0x54080000 0x2000>;
> +
> +			csi@838 {
> +				compatible = "nvidia,tegra210-csi";
> +				reg = <0x838 0x1300>;
> +				assigned-clocks = <&tegra_car TEGRA210_CLK_CILAB>,
> +						  <&tegra_car TEGRA210_CLK_CILCD>,
> +						  <&tegra_car TEGRA210_CLK_CILE>,
> +						  <&tegra_car TEGRA210_CLK_CSI_TPG>;
> +				assigned-clock-parents = <&tegra_car TEGRA210_CLK_PLL_P>,
> +							 <&tegra_car TEGRA210_CLK_PLL_P>,
> +							 <&tegra_car TEGRA210_CLK_PLL_P>;
> +				assigned-clock-rates = <102000000>,
> +						       <102000000>,
> +						       <102000000>,
> +						       <972000000>;
> +
> +				clocks = <&tegra_car TEGRA210_CLK_CSI>,
> +					 <&tegra_car TEGRA210_CLK_CILAB>,
> +					 <&tegra_car TEGRA210_CLK_CILCD>,
> +					 <&tegra_car TEGRA210_CLK_CILE>,
> +					 <&tegra_car TEGRA210_CLK_CSI_TPG>;
> +				clock-names = "csi", "cilab", "cilcd", "cile", "csi_tpg";
> +				power-domains = <&pd_sor>;
> +			};
>  		};
>  
>  		epp {

-- 
Regards,

Laurent Pinchart