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Date:   Mon, 24 Apr 2023 03:47:06 +0300
From:   Laurent Pinchart <laurent.pinchart@ideasonboard.com>
To:     Adam Ford <aford173@gmail.com>
Cc:     linux-arm-kernel@lists.infradead.org,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Shawn Guo <shawnguo@kernel.org>,
        Sascha Hauer <s.hauer@pengutronix.de>,
        Pengutronix Kernel Team <kernel@pengutronix.de>,
        Fabio Estevam <festevam@gmail.com>,
        NXP Linux Team <linux-imx@nxp.com>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will@kernel.org>, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/2] arm64: dts: imx8mn: Enable CSI and ISI Nodes
Message-ID: <20230424004706.GL21943@pendragon.ideasonboard.com>
References: <20230423212656.1381002-1-aford173@gmail.com>
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Hi Adam,

Thank you for the patch.

On Sun, Apr 23, 2023 at 04:26:55PM -0500, Adam Ford wrote:
> The CSI in the imx8mn is the same as what is used in the imx8mm,
> but it's routed to the ISI on the Nano. Add both the ISI and CSI
> nodes, and pointing them to each other. Since the CSI capture is
> dependent on an attached camera, mark both ISI and CSI as
> disabled by default.

I'd then write the subject line as "Add CSI and ISI nodes".

> Signed-off-by: Adam Ford <aford173@gmail.com>
>
> diff --git a/arch/arm64/boot/dts/freescale/imx8mn.dtsi b/arch/arm64/boot/dts/freescale/imx8mn.dtsi
> index 8be8f090e8b8..102550b41f22 100644
> --- a/arch/arm64/boot/dts/freescale/imx8mn.dtsi
> +++ b/arch/arm64/boot/dts/freescale/imx8mn.dtsi
> @@ -1104,6 +1104,24 @@ dsim_from_lcdif: endpoint {
>  				};
>  			};
>  
> +			isi: isi@32e20000 {
> +				compatible = "fsl,imx8mn-isi";
> +				reg = <0x32e20000 0x100>;

The i.MX8MN reference manual documents the ISI registers block size to
be 64kB. Should we use the same here, even if all the registers we need
are within the first 256 bytes ?

> +				interrupts = <GIC_SPI 16 IRQ_TYPE_LEVEL_HIGH>;
> +				clocks = <&clk IMX8MN_CLK_DISP_AXI_ROOT>,
> +					 <&clk IMX8MN_CLK_DISP_APB_ROOT>;
> +				clock-names = "axi", "apb";
> +				fsl,blk-ctrl = <&disp_blk_ctrl>;
> +				power-domains = <&disp_blk_ctrl IMX8MN_DISPBLK_PD_ISI>;
> +				status = "disabled";
> +
> +				port {
> +					isi_in: endpoint {
> +						remote-endpoint = <&mipi_csi_out>;
> +					};
> +				};

This will fail to validate against the ISI DT binding, as they require a
"ports" node. When a single port is present using a "port" node directly
is fine from an OF graph point of view, but to avoid too much complexity
in the ISI binding the consensus was to always require a "ports" node
for the ISI.

> +			};
> +
>  			disp_blk_ctrl: blk-ctrl@32e28000 {
>  				compatible = "fsl,imx8mn-disp-blk-ctrl", "syscon";
>  				reg = <0x32e28000 0x100>;
> @@ -1147,6 +1165,42 @@ disp_blk_ctrl: blk-ctrl@32e28000 {
>  				#power-domain-cells = <1>;
>  			};
>  
> +			mipi_csi: mipi-csi@32e30000 {
> +				compatible = "fsl,imx8mm-mipi-csi2";
> +				reg = <0x32e30000 0x1000>;
> +				interrupts = <GIC_SPI 17 IRQ_TYPE_LEVEL_HIGH>;
> +				assigned-clocks = <&clk IMX8MN_CLK_CAMERA_PIXEL>,
> +						  <&clk IMX8MN_CLK_CSI1_PHY_REF>;
> +				assigned-clock-parents = <&clk IMX8MN_SYS_PLL2_1000M>,
> +							  <&clk IMX8MN_SYS_PLL2_1000M>;
> +				assigned-clock-rates = <333000000>;
> +				clock-frequency = <333000000>;
> +				clocks = <&clk IMX8MN_CLK_DISP_APB_ROOT>,
> +					 <&clk IMX8MN_CLK_CAMERA_PIXEL>,
> +					 <&clk IMX8MN_CLK_CSI1_PHY_REF>,
> +					 <&clk IMX8MN_CLK_DISP_AXI_ROOT>;
> +				clock-names = "pclk", "wrap", "phy", "axi";
> +				power-domains = <&disp_blk_ctrl IMX8MN_DISPBLK_PD_MIPI_CSI>;
> +				status = "disabled";
> +
> +				ports {
> +					#address-cells = <1>;
> +					#size-cells = <0>;
> +
> +					port@0 {
> +						reg = <0>;
> +					};
> +
> +					port@1 {
> +						reg = <1>;
> +
> +						mipi_csi_out: endpoint {
> +							remote-endpoint = <&isi_in>;
> +						};
> +					};
> +				};
> +			};
> +
>  			usbotg1: usb@32e40000 {
>  				compatible = "fsl,imx8mn-usb", "fsl,imx7d-usb", "fsl,imx27-usb";
>  				reg = <0x32e40000 0x200>;

-- 
Regards,

Laurent Pinchart