屏配置

通用屏驱动:

drivers/gpu/drm/panel/panel-simple.c

device-tree:

Required properties:
  power-supply: regulator to provide the supply voltage

Optional properties:
- compatible: value maybe one of the following
             "simple-panel";
             "simple-panel-dsi";

- ddc-i2c-bus: phandle of an I2C controller used for DDC EDID probing
- enable-gpios: GPIO pin to enable or disable the panel
- backlight: phandle of the backlight device attached to the panel

Required properties when compatible is "simple-panel" or "simple-panel-dsi":
- display-timings: see display-timing.txt for information

Optional properties:
- delay,prepare: the time (in milliseconds) that it takes for the panel to
                 become ready and start receiving video data
- delay,enable: the time (in milliseconds) that it takes for the panel to
                display the first valid frame after starting to receive
                video data
- delay,disable: the time (in milliseconds) that it takes for the panel to
                 turn the display off (no content is visible)
- delay,unprepare: the time (in milliseconds) that it takes for the panel
                   to power itself down complete
- bus-format:


Optional properties when compatible is a dsi devices:
- dsi,flags: dsi operation mode related flags
- dsi,format: pixel format for video mode
- dsi,lanes: number of active data lanes

屏配置方式一: 使用短字符串匹配写死的timing

1, 把timings写在drivers/gpu/drm/panel/panel-simple.c中, 直接以短字符匹配, 该方式为upstream推荐的使用方式.

DeviceTree:

panel: panel {
    compatible = "cptt,claa101wb01";
    ddc-i2c-bus = <&panelddc>;
    power-supply = <&vdd_pnl_reg>;
    enable-gpios = <&gpio 90 0>;
    backlight = <&backlight>;
    delay,prepare = <10>;
    delay,enable = <10>;
    delay,disable = <10>;
    delay,unprepare = <10>;
};

drivers/gpu/drm/panel/panel-simple.c:

static const struct drm_display_mode lg_lp097qx1_spa1_mode = {
    .clock = 205210,
    .hdisplay = 2048,
    .hsync_start = 2048 + 150,
    .hsync_end = 2048 + 150 + 5,
    .htotal = 2048 + 150 + 5 + 5,
    .vdisplay = 1536,
    .vsync_start = 1536 + 3,
    .vsync_end = 1536 + 3 + 1,
    .vtotal = 1536 + 3 + 1 + 9,
    .vrefresh = 60,
};
static const struct panel_desc lg_lp097qx1_spa1 = {
    .modes = &lg_lp097qx1_spa1_mode,
    .num_modes = 1,
    .size = {
        .width = 320,
        .height = 187,
    },
};
static const struct of_device_id platform_of_match[] = {
    [...]
    }, {
      .compatible = "lg,lp097qx1-spa1",
      .data = &lg_lp097qx1_spa1,
    }, {
    [...]
}

屏配置方式二: 直接将timing写在dts文件中

2, 把使用display-timings结构, 直接把timing写在dts文件中, 这类适用于简单的屏配置

    panel: panel {
        compatible = "simple-panel-dsi";
        ddc-i2c-bus = <&panelddc>;
        power-supply = <&vdd_pnl_reg>;
        enable-gpios = <&gpio 90 0>;
        backlight = <&backlight>;
        dsi,flags = <MIPI_DSI_MODE_VIDEO |
                 MIPI_DSI_MODE_VIDEO_BURST |
                 MIPI_DSI_MODE_VIDEO_SYNC_PULSE>;
        dsi,format = <MIPI_DSI_FMT_RGB888>;
        dsi,lanes = <4>;
        delay,prepare = <10>;
        delay,enable = <10>;
        delay,disable = <10>;
        delay,unprepare = <10>;

        display-timings {
            native-mode = <&timing0>;
            timing0: timing0 {
                clock-frequency = <160000000>;
                hactive = <1200>;
                vactive = <1920>;
                hback-porch = <21>;
                hfront-porch = <120>;
                vback-porch = <18>;
                vfront-porch = <21>;
                hsync-len = <20>;
                vsync-len = <3>;
                hsync-active = <0>;
                vsync-active = <0>;
                de-active = <0>;
                pixelclk-active = <0>;
            };
        };
    };

屏配置方式三: 使用edid

不填写任何timing, 直接使用edid来获取timing

panel: panel {
    compatible = "simple-panel-dsi";
    //compatible = "simple-panel";
    ddc-i2c-bus = <&panelddc>;
    power-supply = <&vdd_pnl_reg>;
    enable-gpios = <&gpio 90 0>;
    backlight = <&backlight>;
    delay,prepare = <10>;
    delay,enable = <10>;
    delay,disable = <10>;
    delay,unprepare = <10>;
};

Document:

Documentation/devicetree/bindings/display/panel/simple-panel.txt