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Date:   Mon, 24 Apr 2023 03:49:02 +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: <20230424004902.GN21943@pendragon.ideasonboard.com>
References: <20230423212656.1381002-1-aford173@gmail.com>
 <20230424004706.GL21943@pendragon.ideasonboard.com>
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On Mon, Apr 24, 2023 at 03:47:13AM +0300, Laurent Pinchart wrote:
> Hi Adam,

Another comment, do you plan to submit a patch with a camera DT overlay
for an i.MX8MN board ?

> 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