Step1. 添加LCD设备树描述,Includes Backlight Node and ltdc节点
Step2. Add a set of devices to the driver fileID

一、Add device tree description

1. 修改ltdc节点描述

比较重要的属性是remote-endpoint,描述ltdc输出到哪里.

2. 添加ltdcDescription of output interface

	rgblcd: rgblcd {
    
		compatible = "bearpi,rgblcd";
		backlight = &rgblcd_backlight;
		status = "okay";

		port {
    
			rgblcd_in: endpoint {
    
				remote-endpoint = <&ltdc_ep0_out>;
			};
		};
	};

其中remote-endpointUsed to tell the screen driver where to get the data.

3. 添加backlight节点

	rgblcd_backlight: rgblcd-backlight {
    
		compatible = "gpio-backlight";
        gpios = <&gpioe 9 GPIO_ACTIVE_HIGH>;
		default-on;
		status = "okay";
	};

二、Add screen parameters in the driver

1. Add screen parameter description

static const struct drm_display_mode bearpi_rgblcd_mode = {
    
	.clock = 51200,
	.hdisplay = 800,
	.hsync_start = 800 + 46,
	.hsync_end = 800 + 46 + 1,
	.htotal = 800 + 46 + 1 + 210,
	.vdisplay = 480,
	.vsync_start = 480 + 23,
	.vsync_end = 480 + 23 + 1,
	.vtotal = 480 + 23 + 1 + 22,
	.flags = DRM_MODE_FLAG_NVSYNC | DRM_MODE_FLAG_NHSYNC,
};

static const struct panel_desc bearpi_rgblcd_desc = {
    
	.modes = &bearpi_rgblcd_mode,
    .num_modes = 1,
    .bpc = 6,
	.size = {
    
		.width = 152,
		.height = 91,
	},
    .bus_format = MEDIA_BUS_FMT_RGB888_1X24,
    .bus_flags = DRM_BUS_FLAG_DE_HIGH | DRM_BUS_FLAG_PIXDATA_DRIVE_POSEDGE,
};

2. Add device compatibility

三、测试