Edp

* How to Enable eDP Module

1. Driver Compile
Ensure below configures have been selected:

CONFIG_ROCKCHIP_ANALOGIX_DP=y
CONFIG_PHY_ROCKCHIP_DP=y

Bellow drivers have been compiled:

drivers/gpu/drm/rockchip/analogix_dp-rockchip.c
drivers/gpu/drm/bridge/analogix/

2. DTS Setting
2.1 Enable eDP Device Node：

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

&edp_phy {
        status = "okay";
};

2.2 eDP device node parameters, there are two properties for eDP device:

force-hpd;
ports {
        edp_out: port@1 {
                reg = <1>;
                #address-cells = <1>;
                #size-cells = <0>;
                edp_out_panel: endpoint {
                        reg = <0>;
                        remote-endpoint = <&panel_in_edp>;
                };
        };
};
  • "force-hpd": forcing regard panel is connected for some panel without Hotplug pin.
  • "ports": pointed to panel device node

* How To Debug eDP Module

3. Whether eDP display card has been registered successfully

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

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

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

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

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

$ cd /sys/class/drm/card0-eDP-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 eDP panel, please check bellow information:

  • Check the eDP 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 eDP DTS Configure：

include "rk3288.dtsi"

edp_panel: edp-panel {
        compatible ="lg,lp079qx1-sp0v", "simple-panel";
        backlight = <&backlight>;
        enable-gpios = <&gpio7 4 GPIO_ACTIVE_HIGH>;
        pinctrl-0 = <&lcd_cs>;
        ports {
                panel_in: port {
                        panel_in_edp: endpoint {
                                remote-endpoint = <&edp_out_panel>;
                        };
                };
        };
};

&edp {
        force-hpd;
        status = "okay";

        ports {
                edp_out: port@1 {
                        reg = <1>;
                        #address-cells = <1>;
                        #size-cells = <0>;
                        edp_out_panel: endpoint {
                                reg = <0>;
                                remote-endpoint = <&panel_in_edp>;
                        };
                };
        };
};

&edp_phy {
        status = "okay";
};