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Use a 7 inch TFT display with RoadRunner SOM

This article explain how to manage a 7 inch TFT display using the DPI port of RoarRunner SOM

Wirings

Data lines:

Example of wiring in 666 mode with a TFT display:

LCD 7 inch
1 VLED-
2 VLED+
3 GND GND
4 3V3 3V3
5 R0 GND
6 R1 GND
7 R2 PC22
8 R3 PC23
9 R4 PC24
10 R5 PC25
11 R6 PC26
12 R7 PC27
13 G0 GND
14 G1 GND
15 G2 PC16
16 G3 PC17
17 G4 PC18
18 G5 PC19
19 G6 PC20
20 G7 PC21
21 B0 GND
22 B1 GND
23 B2 PC10
24 B3 PC11
25 B4 PC12
26 B5 PC13
27 B6 PC14
28 B7 PC15
29 GND
30 PCLK PD0
31 DISP 3V3
32 HSYNC PC31
33 VSYNC PC30
34 DE PD1
35 NC
36 GND GND
37 NC
38 NC
39 NC
40 NC

Device tree apb section

hlcdc: hlcdc@f0000000 {
    status = "okay";

    hlcdc-display-controller {

        pinctrl-names = "default";
        pinctrl-0 = <&pinctrl_lcd_base &pinctrl_lcd_rgb666>;

        port@0 {
            #address-cells = <1>;
            #size-cells = <0>;
            hlcdc_panel_output: endpoint@0 {
                reg = <0>;
                remote-endpoint = <&panel_input>;
            };
        };
    };

    hlcdc_pwm: hlcdc-pwm {
        pinctrl-names = "default";
        pinctrl-0 = <&pinctrl_lcd_pwm>;
    };

};  

backlight: backlight {
    compatible = "pwm-backlight";
    pwms = <&hlcdc_pwm 0 50000 0>;
    brightness-levels = <0 4 8 16 32 64 128 255>;
    default-brightness-level = <7>;
    power-supply = <&bl_reg>;
    status = "okay";
};

bl_reg: backlight_regulator {
    compatible = "regulator-fixed";
    regulator-name = "backlight-power-supply";
    regulator-min-microvolt = <5000000>;
    regulator-max-microvolt = <5000000>;
    status = "okay";
};

panel: panel {
    /* compatible = "pda,91-00156-a0", "simple-panel"; */
    compatible = "innolux,g070y2-l01", "simple-panel";
    backlight = <&backlight>;
    power-supply = <&panel_reg>;
    #address-cells = <1>;
    #size-cells = <0>;
    status = "okay";

    port@0 {
        reg = <0>;
        #address-cells = <1>;
        #size-cells = <0>;

        panel_input: endpoint@0 {
            reg = <0>;
            remote-endpoint = <&hlcdc_panel_output>;
        };
    };
};

panel_reg: panel_regulator {
    compatible = "regulator-fixed";
    regulator-name = "panel-power-supply";
    regulator-min-microvolt = <3300000>;
    regulator-max-microvolt = <3300000>;
    status = "okay";
};

Device tree - pinctrl@fc038000 section

pinctrl_lcd_base: pinctrl_lcd_base {
    pinmux = <PIN_PC30__LCDVSYNC>,
         <PIN_PC31__LCDHSYNC>,
         <PIN_PD1__LCDDEN>,
         <PIN_PD0__LCDPCK>;
    bias-disable;
    /* atmel,drive-strength = <ATMEL_PIO_DRVSTR_ME>; */
};


pinctrl_lcd_rgb666: pinctrl_lcd_rgb666 {
    pinmux = <PIN_PC10__LCDDAT2>,
         <PIN_PC11__LCDDAT3>,
         <PIN_PC12__LCDDAT4>,
         <PIN_PC13__LCDDAT5>,
         <PIN_PC14__LCDDAT6>,
         <PIN_PC15__LCDDAT7>,
         <PIN_PC16__LCDDAT10>,
         <PIN_PC17__LCDDAT11>,
         <PIN_PC18__LCDDAT12>,
         <PIN_PC19__LCDDAT13>,
         <PIN_PC20__LCDDAT14>,
         <PIN_PC21__LCDDAT15>,
         <PIN_PC22__LCDDAT18>,
         <PIN_PC23__LCDDAT19>,
         <PIN_PC24__LCDDAT20>,
         <PIN_PC25__LCDDAT21>,
         <PIN_PC26__LCDDAT22>,
         <PIN_PC27__LCDDAT23>;
    bias-disable;
};

pinctrl_lcd_pwm: pinctrl_lcd_pwm {
    pinmux = <PIN_PC28__LCDPWM>;
    bias-disable;
};

Links

Roadrunner technical documentation Buy on-line

Bruna Mandolino