IMX8M MIPI DSI device tree question

[J_W]

Hi,

I am attempting to get MIPI DSI signals out from my imx8m - however I don't think I have my device tree configured quite right and I need some help.

I am including these from imx8mm.dtsi:

aips4: bus@32c00000 {
			compatible = "fsl,aips-bus", "simple-bus";
			reg = <0x32c00000 0x400000>;
			#address-cells = <1>;
			#size-cells = <1>;
			ranges = <0x32c00000 0x32c00000 0x400000>;

			lcdif: lcdif@32e00000 {
				#address-cells = <1>;
				#size-cells = <0>;
				compatible = "fsl,imx8mm-lcdif";
				reg = <0x32e00000 0x10000>;
				clocks = <&clk IMX8MM_CLK_LCDIF_PIXEL>,
					 <&clk IMX8MM_CLK_DISP_AXI_ROOT>,
					 <&clk IMX8MM_CLK_DISP_APB_ROOT>;
				clock-names = "pix", "disp-axi", "disp-apb";
				assigned-clocks = <&clk IMX8MM_CLK_LCDIF_PIXEL>,
						  <&clk IMX8MM_CLK_DISP_AXI>,
						  <&clk IMX8MM_CLK_DISP_APB>;
				assigned-clock-parents = <&clk IMX8MM_VIDEO_PLL1_OUT>,
							 <&clk IMX8MM_SYS_PLL2_1000M>,
							 <&clk IMX8MM_SYS_PLL1_800M>;
				assigned-clock-rate = <594000000>, <500000000>, <200000000>;
				interrupts = <GIC_SPI 5 IRQ_TYPE_LEVEL_HIGH>;
				lcdif-gpr = <&dispmix_gpr>;
				resets = <&lcdif_resets>;
				power-domains = <&dispmix_pd>;
				status = "disabled";

				lcdif_disp0: port@0 {
					reg = <0>;

					lcdif_to_dsim: endpoint {
						remote-endpoint = <&dsim_from_lcdif>;
					};
				};
			};

			mipi_dsi: mipi_dsi@32e10000 {
				#address-cells = <1>;
				#size-cells = <0>;
				compatible = "fsl,imx8mm-mipi-dsim";
				reg = <0x32e10000 0x400>;
				clocks = <&clk IMX8MM_CLK_DSI_CORE>,
					 <&clk IMX8MM_CLK_DSI_PHY_REF>;
				clock-names = "cfg", "pll-ref";
				assigned-clocks = <&clk IMX8MM_CLK_DSI_CORE>,
						  <&clk IMX8MM_CLK_DSI_PHY_REF>;
				assigned-clock-parents = <&clk IMX8MM_SYS_PLL1_266M>,
							 <&clk IMX8MM_CLK_24M>;
				assigned-clock-rates = <266000000>, <12000000>;
				interrupts = <GIC_SPI 18 IRQ_TYPE_LEVEL_HIGH>;
				dsi-gpr = <&dispmix_gpr>;
				resets = <&mipi_dsi_resets>;
				power-domains = <&mipi_pd>;
				status = "disabled";

				port@0 {
					dsim_from_lcdif: endpoint {
						remote-endpoint = <&lcdif_to_dsim>;
					};
				};
			};

In my device tree I have edited the properties as follows:

&i2c4 {
	#address-cells = <1>;
	#size-cells = <0>;
	clock-frequency = <100000>; /* 100kHz */
	pinctrl-names = "default";
	pinctrl-0 = <&pinctrl_i2c4>;
	status = "okay";
	
	lt_bridge: lt9211@2d {
		compatible = "lontium,lt9211";
		reg=<0x2d>;
		pinctrl-0 = <&pinctrl_lt9211>;
		reset-gpios = <&gpio5 10 GPIO_ACTIVE_LOW>;
		/*vccio-supply = <&??>;*/
		status = "okay";

		ports {
			#address-cells = <1>;
			#size-cells = <0>;
			
			port@0 { /*primary input*/
            			reg = <0>;
            			lt9211_mipi_in: endpoint {
				      remote-endpoint = <&host_mipi_out>;
				};
			};

          		/*port@2 { /
            			reg = <2>;
            			lt9211_mipi_out: endpoint {
              				remote-endpoint = <&dsim_from_lcdif>;
            			};
          		};*/
		};
	}; 
};

&lcdif {
	status = "okay";
};

&mipi_dsi {
	status = "okay";
	
	port@1 {
		host_mipi_out: endpoint {
			remote-endpoint = <&lt9211_mipi_in>;
			/*attach-bridge; not needed ??? */
		};
	};
};

I have verified that the i2c bus works. I am able to use "gpioset 4 10=1" to activate my lt9211 and it responds to commands send over the i2cset and i2cget.  

I am a bit confused regarding 
https://www.kernel.org/doc/Documentation/devicetree/bindings/display/bridge/lontium%2Clt9211.yaml

which lists both port0 and port2 as required properties. Is port2 supposed to be lcdif_to_dsim or something else? Do I add a new data line to the mipi_dsi node? 

The current tree outputs error:

[ 2.216086] [drm:drm_bridge_attach] *ERROR* failed to attach bridge /soc@0/bus@32c00000/mipi_dsi@32e10000 to encoder DSI-34: -19
[ 2.235960] imx_sec_dsim_drv 32e10000.mipi_dsi: failed to bind sec dsim bridge: -19

[Bio_TICFSL]

Hello,

It looks like the pincontrol is not dong it jobs cause it have use a gpio in another part of the device tree. But besides that you need module to have the MIPI-DSI running.

Regards

[J_W]

Yes, of course I need a module. I have a module - that's what I'm trying to load when I get the error. I have discovered that the error is likely due to missing the port2 to Display driver in the device tree. I am a bit unsure how to bind it though.