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MIPI DSI display problems

Question asked by Simon Stürz on May 21, 2015
Latest reply on Apr 19, 2017 by Kunal Kulshrestha

Hello everyone!

 

I am currently trying to enable my MIPI-DSI display and I have some problems with my module and I hope you can help me.

I used the https://github.com/t-mon/linux-linaro-stable-mx6/blob/linux-linaro-lsk-v3.14-mx6/drivers/video/mxc/mxcfb_hx8369_wvga.c  as template for the panel and changed:

  • mipid_hx8369_lcd_setup ()
  • struct mipi_lcd_config lcd_config
  • truly_lcd_modedb[]

 

My Display: http://kingtechgroup.en.alibaba.com/product/60176023919-801063540/1_5_inch_320x320_circular_lcd_display.html

The datasheet of the OTM3201A is in the attachment.

 

My current code can be found here:

https://guh.guru/downloads/scripts/mxcfb_hx8369_wvga.c

 

For the init section I used the recommendations from Kingtech.

At the current development state I am controlling the display brightness directly with the PWM.

 

The kernel log seems to be ok...

[    0.074780] mipi_dsi_pwr_on: no parameters
[    0.597368] mxc_mipi_dsi 21e0000.mipi: i.MX MIPI DSI driver probed
[    0.598035] mxc_sdc_fb fb.24: register mxc display driver mipi_dsi
[    0.606523] mxc_mipi_dsi 21e0000.mipi: start MIPI DSI LCD setup.
[    0.606530] mxc_mipi_dsi 21e0000.mipi: Engineering Mode Enable...OK.
[    0.608513] mxc_mipi_dsi 21e0000.mipi: Register write mode enable...OK.
[    0.608520] mxc_mipi_dsi 21e0000.mipi: Display Inversion Control...OK.
[    0.610511] mxc_mipi_dsi 21e0000.mipi: Set pixel format - 24 bits/pixel...OK.
[    0.612512] mxc_mipi_dsi 21e0000.mipi: RGB Interface Blanking Porch setting...OK.
[    0.612518] mxc_mipi_dsi 21e0000.mipi: Timing structure register...OK.
[    0.614511] mxc_mipi_dsi 21e0000.mipi: Landscape MIPI Video Mode...OK.
[    0.616510] mxc_mipi_dsi 21e0000.mipi: MIPI RX Delay Setting...OK.
[    0.618510] mxc_mipi_dsi 21e0000.mipi: Gamma Voltage adjust Control...OK.
[    0.618516] mxc_mipi_dsi 21e0000.mipi: Display Inversion Off...OK.
[    0.630509] mxc_mipi_dsi 21e0000.mipi: Gamma Correction Characteristics Setting...OK.
[    0.630516] mxc_mipi_dsi 21e0000.mipi: Sleep out...OK.
[    0.632513] mxc_mipi_dsi 21e0000.mipi: Display ON...OK.

 

The frame buffer device seems to be ok...

$ cat /sys/class/graphics/fb0/mode
U:320x320p-60

 

My uEnv.txt file:

 

mmcargs=setenv bootargs root=/dev/mmcblk0p1 rootfstype=ext4 rootwait console=tty1 console=ttymxc0,115200 video=mxcfb1:dev=mipi_dsi rd.dm=0 rd.luks=0 rd.lvm=0 raid=noautodetect pci=nomsi ahci_imx.hotplug=1 consoleblank=0 vt.global_cursor_default=0

 

My device tree blob configuration (MIPI-DSI relevant sections):

 

aliases {

     mxcfb0 = &mxcfb1;

};

 

reg_mipi_dsi_pwr_on: mipi_dsi_pwr_on {

     compatible = "regulator-fixed";

     regulator-name = "mipi_dsi_pwr_on";

     gpio = <&gpio6 14 0>;

     enable-active-high;

};

 

mipi_dsi_reset: mipi-dsi-

     compatible = "gpio-

     reset-gpios = <&gpio7 12

     reset-delay-us = <

     #reset-cells = <0>;

};

 

mxcfb1: fb@0 {

     compatible = "fsl,mxc_sdc_fb";

     disp_dev = "mipi_dsi";

     interface_pix_fmt = "RGB565";

     mode_str ="TRULY-WVGA";

     default_bpp = <24>;

     int_clk = <0>;

     late_init = <0>;

     status = "okay";

};

 

&mipi_dsi {

        dev_id = <0>;

        disp_id = <0>;

        lcd_panel = "TRULY-WVGA";

        disp-power-on-supply = <&reg_mipi_dsi_pwr_on>;

        resets = <&mipi_dsi_reset>;

        status = "okay";

};

 

The problem: the display never shows anything...I tried startx, i tried fbi... nothing. Just a black display (with brigthness on).

 

I think the problem is the display configuration. How do I calculate the pixel clock? How do I select the sync mode? I found nothing in the datasheet and Kingtech could not help me.

 

$ fbset --info
mode "320x320-227"
    # D: 26.399 MHz, H: 76.742 kHz, V: 227.047 Hz
    geometry 320 320 320 320 24
    timings 37880 8 8 6 6 8 6
    sync 0x80000000
    rgba 8/16,8/8,8/0,0/0
endmode
Frame buffer device information:
    Name        : DISP3 BG
    Address     : 0x20080000
    Size        : 307200
    Type        : PACKED PIXELS
    Visual      : TRUECOLOR
    XPanStep    : 1
    YPanStep    : 1
    YWrapStep   : 1
    LineLength  : 960
    Accelerator : No

 

I hope I have not forgotten any information. I am thankful for any suggestions.

 

Best reguards,

Simon

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