[RK3399][Android7.1] Display模块配置屏幕时序方法

OS: Android 7.1
Board: Firefly-RK3399
Kernel: v4.4.55

rk3399平台上提供了两种方法来配置屏的时序参数，uboot也一样。

时序参数写在源代码中:

比如当前用的edp屏,　dts只有背光，gpio这些配置。
rk3399-firefly-edp.dts:

    edp_panel: edp-panel {
        compatible = "lg,lp079qx1-sp0v";
        bus-format = <MEDIA_BUS_FMT_RGB666_1X18>;
        backlight = <&backlight>;
        ......
        power_ctr: power_ctr {
               rockchip,debug = <0>;
               lcd_en: lcd-en {
                       gpios = <&gpio1 1 GPIO_ACTIVE_HIGH>;
                       pinctrl-names = "default";
                       pinctrl-0 = <&lcd_panel_enable>;
                       rockchip,delay = <20>;
               };
               lcd_rst: lcd-rst {
                       gpios = <&gpio4 29 GPIO_ACTIVE_HIGH>;
                       pinctrl-names = "default";
                       pinctrl-0 = <&lcd_panel_reset>;
                       rockchip,delay = <20>;
               };
       };
    };

对应的时序参数配置是在panel-simple.c中

static const struct of_device_id platform_of_match[] = {
......
     {
        .compatible = "lg,lp079qx1-sp0v",
        .data = &lg_lp079qx1_sp0v,
     }, 
......
};

lg_lp079qx1_sp0v:

static const struct panel_desc lg_lp079qx1_sp0v = {
    .modes = &lg_lp079qx1_sp0v_mode,
    .num_modes = 1,
    .size = {
        .width = 129,
        .height = 171,
    },
    .bus_format = MEDIA_BUS_FMT_RGB666_1X18,
};

lg_lp079qx1_sp0v_mode:

static const struct drm_display_mode lg_lp079qx1_sp0v_mode = {
    .clock = 200000,
    .hdisplay = 1536,
    .hsync_start = 1536 + 12,
    .hsync_end = 1536 + 12 + 16,
    .htotal = 1536 + 12 + 16 + 48,
    .vdisplay = 2048,
    .vsync_start = 2048 + 8,
    .vsync_end = 2048 + 8 + 4,
    .vtotal = 2048 + 8 + 4 + 8,
    .vrefresh = 60,
    .flags = DRM_MODE_FLAG_NVSYNC | DRM_MODE_FLAG_NHSYNC,
};

---

时序写在dts中：
这个方式是和rk3288一样的，比如dts中的mipi屏配置。

rk3399-firefly-mipi.dsti:

&mipi_dsi {
    status = "okay";
    dsi_panel: panel {
        compatible ="simple-panel-dsi";
        status = "okay";
        ......
        disp_timings: display-timings {
                          native-mode = <&timing0>;
                          timing0: timing0 {
                                       clock-frequency = <80000000>;
                                       hactive = <768>;
                                       vactive = <1024>;
                                       hsync-len = <20>;   //20, 50
                                       hback-porch = <130>; //50, 56
                                       hfront-porch = <150>;//50, 30
                                       vsync-len = <40>;
                                       vback-porch = <130>;
                                       vfront-porch = <136>;
                                       hsync-active = <0>;
                                       vsync-active = <0>;
                                       de-active = <0>;
                                       pixelclk-active = <0>;
                                   };
                      };
    };
};