6、Lctech Pi(F1C200S)4.3寸(480*272)16位RGB565LCD屏驱动适配(CherryPi，Mangopi，F1C100S)

本次主要参考：
https://blog.csdn.net/wending1986/article/details/106837597/
http://blog.chinaunix.net/uid-20543672-id-3246283.html
https://wiki.sipeed.com/soft/Lichee/zh/Nano-Doc-Backup/index.html
李山文大佬
（如果方便请给这几位大佬一个关注）

注意代码块之间的空行

如有不足之处，欢迎指出。

1、设置LCD基础参数（需要自己去根据屏幕参数进行适配）
在drivers/gpu/drm/panel/panel-simple.c文件中，第2713行开始修改如下：

static const struct drm_display_mode qd43003c0_40_mode = {
    .clock = 9000,
    .hdisplay = 480,
    .hsync_start = 480 + 8,
    .hsync_end = 480 + 8 + 4,
    .htotal = 480 + 8 + 4 + 43,
    .vdisplay = 272,
    .vsync_start = 272 + 8,
    .vsync_end = 272 + 8 + 4,
    .vtotal = 272 + 8 + 4 + 12,
    .vrefresh = 60,
};

部分参数含义如下：
    hdisplay：有效显示区水平像素数量，对应Active Width
    hsync_start：水平同步开始，对应hdispay + HFP
    hsync_end：水平同步结束，对应hdisplay + HFP + HSYNC width(HPW)
    htotal：水平总像素，对应hdisplay + HFP + HSYNC width + HBP
    vdisplay：垂直显示像素，对应Active Height
    vsync_start：垂直同步开始，对应vdispay + VFP
    vsync_end：垂直像素结束，对应vdisplay + VFP + VSYNC width(VPW)
    vtotal：垂直总像素，对应vdisplay + VFP + VSYNC width + VBP
    vrefresh：刷新率

第2726行开始修改如下：

static const struct panel_desc qd43003c0_40 = {
    .modes = &qd43003c0_40_mode,
    .num_modes = 1,
    //.bpc = 8,
    .size = {
        .width = 95,
        .height = 53,
    },
    .bus_format = MEDIA_BUS_FMT_RGB565_1X16//MEDIA_BUS_FMT_RGB888_1X24
};

其中需要注意，参数bus_format设置为：MEDIA_BUS_FMT_RGB565_1X16；width与height为液晶尺寸。

2、配置设备树
2.1、修改suniv-f1c100s.dtsi文件
打开linux-5.7.1/arch/arm/boot/dts/suniv-f1c100s.dtsi文件。
在第38行插入如下代码：

de: display-engine {
    .compatible = “allwinner,suniv-f1c100s-display-engine”;
    .allwinner,pipelines = <&fe0>;
    .status = “disabled”;
};

在soc->pio 下（第104行）添加如下代码：

lcd_rgb565_pins: lcd-rgb565-pins {
    pins = “PD1”, “PD2”, “PD3”, “PD4”, “PD5”,
        “PD6”, “PD7”, “PD8”, “PD9”, “PD10”, “PD11”,
        “PD13”, “PD14”, “PD15”, “PD16”, “PD17”,
        “PD18”, “PD19”, “PD20”, “PD21”;
    function = “lcd”;
};

在第172~173行中间，添加如下代码：

tcon0: lcd-controller@1c0c000 {compatible = "allwinner,suniv-f1c100s-tcon";reg = <0x01c0c000 0x1000>;interrupts = <29>;clocks = <&ccu CLK_BUS_LCD>,<&ccu CLK_TCON>,<&osc24M>;	/* Still unknown */clock-names = "ahb","tcon-ch0","tcon-ch1";clock-output-names = "tcon-pixel-clock";resets = <&ccu RST_BUS_LCD>;reset-names = "lcd";status = "disabled";ports {#address-cells = <1>;#size-cells = <0>;tcon0_in: port@0 {#address-cells = <1>;#size-cells = <0>;reg = <0>;tcon0_in_be0: endpoint@0 {reg = <0>;remote-endpoint = <&be0_out_tcon0>;};};tcon0_out: port@1 {#address-cells = <1>;#size-cells = <0>;reg = <1>;};};
};fe0: display-frontend@1e00000 {compatible = "allwinner,suniv-f1c100s-display-frontend";reg = <0x01e00000 0x20000>;interrupts = <30>;clocks = <&ccu CLK_BUS_DE_FE>, <&ccu CLK_DE_FE>,<&ccu CLK_DRAM_DE_FE>;clock-names = "ahb", "mod","ram";resets = <&ccu RST_BUS_DE_FE>;status = "disabled";ports {#address-cells = <1>;#size-cells = <0>;fe0_out: port@1 {#address-cells = <1>;#size-cells = <0>;reg = <1>;fe0_out_be0: endpoint@0 {reg = <0>;remote-endpoint = <&be0_in_fe0>;};};};
};be0: display-backend@1e60000 {compatible = "allwinner,suniv-f1c100s-display-backend";reg = <0x01e60000 0x10000>;reg-names = "be";interrupts = <31>;clocks = <&ccu CLK_BUS_DE_BE>, <&ccu CLK_DE_BE>,<&ccu CLK_DRAM_DE_BE>;clock-names = "ahb", "mod","ram";resets = <&ccu RST_BUS_DE_BE>;reset-names = "be";assigned-clocks = <&ccu CLK_DE_BE>;assigned-clock-rates = <300000000>;ports {#address-cells = <1>;#size-cells = <0>;be0_in: port@0 {#address-cells = <1>;#size-cells = <0>;reg = <0>;be0_in_fe0: endpoint@0 {reg = <0>;remote-endpoint = <&fe0_out_be0>;};};be0_out: port@1 {#address-cells = <1>;#size-cells = <0>;reg = <1>;be0_out_tcon0: endpoint@0 {reg = <0>;remote-endpoint = <&tcon0_in_be0>;};};};
};

完成之后，保存退出。

2.2、修改suniv-f1c100s-licheepi-nano.dts文件
打开linux-5.7.1/arch/arm/boot/dts/suniv-f1c100s-licheepi-nano.dts文件。
在第9行插入如下代码：

#include <dt-bindings/gpio/gpio.h>

在第26行~27行中间，添加如下代码：

panel: panel {compatible = "qiaodian,qd43003c0-40", "simple-panel";#address-cells = <1>;#size-cells = <0>;enable-gpios = <&pio 4 6 GPIO_ACTIVE_HIGH>;port@0 {reg = <0>;#address-cells = <1>;#size-cells = <0>;panel_input: endpoint@0 {reg = <0>;remote-endpoint = <&tcon0_out_lcd>;};};
};

在第40行下面，也就是文档最后添加如下代码：

&be0 {status = "okay";
};&fe0 {status = "okay";
};&de {status = "okay";
};&tcon0 {pinctrl-names = "default";pinctrl-0 = <&lcd_rgb565_pins>;status = "okay";
};&tcon0_out {tcon0_out_lcd: endpoint@0 {reg = <0>;remote-endpoint = <&panel_input>;};
};

完成之后，保存退出。

3、修改内核代码，配置fb
在linux-5.7.1/drivers/gpu/drm/sun4i/文件夹下，需要修改sun4i_tcon.c、sun4i_drv.c、sun4i_backend.c等文件。因为这些文件的配置是参考其他大佬给的资料完成，不予以外示。

4、uboot相关配置
本次不进行uboot的相关编译。因为在uboot启动完成到内核启动，会有花屏一闪而过。一直没有很好的解决。相关参数如下(有些为下面单词前两个字母的缩写)：

xres; /* 可见分辨率 /
yres;
/ 时序: 所有值都以像素时钟为单位（当然除了像素时钟本身） /
pixclock; / 像素时钟（单位：微秒） /
left_margin; / 从行同步到图像左边沿的像素时钟数 /
right_margin; / 从行同步到图像右边沿的像素时钟数 /
upper_margin; / 从场同步到图像上边沿的行数 /
lower_margin; / 从场同步到图像下边沿的行数 /
hsync_len; / 行同步时间长度（像素时钟数） /
vsync_len; / 场同步时间长度（行数） /
sync; / see FB_SYNC_* /
vmode; / see FB_VMODE_* */

5、进行编译与运行
将编译后的zImage，suniv-f1c100s-licheepi-nano.dtb下载到sunxi-fel.exe同级目录下。
用两根type-c线将电脑与CherryPi-F1C200S连接起来，在串口终端以115200 8n1配置打开串口。
按一下板载RST键后，在windows命令终端进入到sunxi-fel.exe同级目录下，执行以下命令可以看到串口终端有log打印，LCD屏有log显示：