LCD integration with IMX6ULL

karth_t — Mon, 15 Feb 2021 19:01:35 GMT

I am trying to integrate an LCD module with IMX6ULL. I am trying to use the lcdif node for the device tree to bring up my LCD. I am not using a build environment like Yocto, instead i am using a standalone Kernel source code building with my tool chain.

I have written my own customized device tree file and i have added the lcdif node under the aips2 tree.

lcdif: lcdif@21c8000 { compatible = "fsl,imx6ul-lcdif", "fsl,imx28-lcdif"; reg = <0x021c8000 0x4000>; interrupts = <GIC_SPI 5 IRQ_TYPE_LEVEL_HIGH>; assigned-clocks = <&clks IMX6UL_CLK_LCDIF_PRE_SEL>; assigned-clock-parents = <&clks IMX6UL_CLK_PLL5_VIDEO_DIV>; clocks = <&clks IMX6UL_CLK_LCDIF_PIX>, <&clks IMX6UL_CLK_LCDIF_APB>, <&clks IMX6UL_CLK_DUMMY>; clock-names = "pix", "axi", "disp_axi"; pinctrl-names = "default"; pinctrl-0 = <&pinctrl_lcdif_dat &pinctrl_lcdif_ctrl>; lcd-supply = <&reg_3v3>; display= <&display0>; status = "okay"; display0: display@0 { bits-per-pixel = <16>; bus-width = <24>; display-timings { native-mode = <&timing0>; timing0: timing0 { clock-frequency = <50000000>; hactive = <800>; vactive = <480>; hback-porch = <1>; hfront-porch = <200>; hsync-len = <87>; vback-porch = <29>; vfront-porch = <200>; vsync-len = <3>; hsync-active = <0>; vsync-active = <0>; de-active = <1>; pixelclk-active = <0>; }; }; }; }; mxcfb1: fb@0 { compatible = "fsl,mxc_sdc_fb"; disp_dev = "lcd"; interface_pix_fmt = "RGB24"; //mode_str ="EA7-WVGA"; default_bpp = <24>; int_clk = <0>; late_init = <0>; status = "okay"; };

I have the "MXC Framebuffer support" enabled. But i am stuck with this error during bootup.

[drm] Supports vblank timestamp caching Rev 2 (21.10.2013). [drm] No driver support for vblank timestamp query. OF: graph: no port node found in /soc/aips-bus@02100000/lcdif@21c8000 mxsfb 21c8000.lcdif: Failed to create outputs

Please let me know what i am doing wrong or if i am missing something important here. I know i am.

Also please feel free to ask for more details, if the above is not enough.

Thanks for your time and support.

EDIT: I almost missed to add one more question. The display timing variables in the device tree is probably wrong and i am assuming that even if they are wrong, i can still manage a /dev/fb0 on my Linux. I understand that i might need to get the variables right to get my LCD to display something right. Am i wrong in assuming something like that ?

Re: LCD integration with IMX6ULL

igorpadykov — Fri, 19 Feb 2021 03:58:29 GMT

Hi karth_t

reason for error may be that you are using "standalone Kernel source code building with my tool chain".

May be recommended to try nxp original linux from source.codeaurora.org/external/imx/linux-imx repository

https://source.codeaurora.org/external/imx/linux-imx/tree/?h=imx_5.4.70_2.3.0

Documentation :

https://www.nxp.com/design/software/embedded-software/i-mx-software/embedded-linux-for-i-mx-applications-processors:IMXLINUX?tab=In-Depth_Tab

Issues with other linux sources may be posted on meta-fsl-arm mailing list, so that someone familiar

with it could try to assist you.
https://lists.yoctoproject.org/g/meta-freescale

Best regards
igor

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LCD integration with IMX6ULL

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