* How to Enable MIPI Module


1. Driver Compile
Ensure below configures have been selected:

CONFIG_ROCKCHIP_DW_MIPI_DSI=y

Bellow drivers have been compiled:

drivers/gpu/drm/rockchip/dw-mipi-dsi.c

2. DTS Setting
2.1 Enable MIPI Device Node:

  • Include the SoC DTS 'rk3288.dtsi' file.
  • Set the MIPI device node state to 'okay'.
include "rk3288.dtsi"
&mipi_dsi {
        status = "okay";
};

2.2 MIPI device node parameters, there're only one property for MIPI device:

&mipi_dsi {
        panel {
                compatible ="boe,tv080wum-nl0";
                reg = <0>;
                backlight = <&backlight>;
                enable-gpios = <&gpio1 13 GPIO_ACTIVE_HIGH>;
                status = "okay";
        };
};
  • "panel": Define the right panel device node.

* How To Debug MIPI Module

3. Whether MIPI display card has been registered successfully

If the MIPI display card has been created, it would create a sysfs debug directory.

$ ls /sys/class/drm/card0-DSI-1

So you just need to check that directory. If that directory is missing in your machine board, please check:

  • Whether MIPI have been enabled in DTS files.
  • Whether MIPI panel have been registered successfully.
  • Whether you have available VOP module for MIPI.
  • Check the kernel log for more detail (dmesg | grep mipi)

4. Check MIPI display card status: status, enabled, modes

$ cd /sys/class/drm/card0-DSI-1
$ cat status  # should printed "connected" or "disconnected"
$ cat enabled # should printed "enabled" or "disabled"
$ cat modes   # should printed the available mode list, like 1536x2048

5. If you still have no picture on MIPI panel, please check bellow information:

  • Check the MIPI panel power supply.
  • Check the panel datasheet, ensure you have configured the timing and power sequence rightly.
  • Check the hardware connected status, or test the panel on workable board.

* Reference MIPI DTS Configure:

include "rk3288.dtsi"

&mipi_dsi {
        status = "okay";
        panel {
                compatible ="boe,tv080wum-nl0";
                reg = <0>;
                backlight = <&backlight>;
                enable-gpios = <&gpio1 13 GPIO_ACTIVE_HIGH>;
                status = "okay";
        };
};