IMX8M MIPI DSI device tree question

J_W — Thu, 01 Jun 2023 14:51:28 GMT

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

Re: IMX8M MIPI DSI device tree question

Bio_TICFSL — Mon, 05 Jun 2023 14:34:16 GMT

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

Re: IMX8M MIPI DSI device tree question

J_W — Wed, 07 Jun 2023 08:33:13 GMT

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.

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