Based on Taishanpai's 3.0-inch screen adapter board (including touch control)

Previously, a 3.1-inch screen that a master had open-sourced was out of stock. Then I saw that a similar 3.0-inch screen was still available, and it was about 20 yuan cheaper than the 3.1-inch screen. So I thought I would use it to test and use it, and at the same time, I wanted to verify the content I had learned.
Screen Taobao link: 3-inch screen LCD 3.0-inch TFT LCD resolution 480*854 MIPI RGB display with touch screen TP
 
1. Software part
The software part includes two parts, namely display and touch
(1) Display part The
display part is to modify the corresponding MIPI device tree program according to the screen data provided by the manufacturer. They are timing information and MIPI initialization sequence information. The data provided by the manufacturer is shown in the figure below (the file is in the attachment D300N9307V0正.txt).
Modify the information in the file SDK/kernel/arch/arm64/boot/dts/rockchip/tspi-rk3566-dsi-v10.dtsi according to the information in the above figure. The modified content is shown in the figure below (the file is attached tspi-rk3566-dsi-v10.dtsi).
 
After modification, be sure to modify the header file of the tspi-rk3566-user-v10.dts file in the same path, turn off HDMI and turn on MIPI, as shown in the figure below.
The above is the modification of the device tree code of the display part
 
(2) Touch part
I have not done the touch part yet, but you can refer to the 3.1-inch screen touch code, which has been tested and is effective. The open source link of the master is as follows:
Feng Moxi/ TSPI-D310T9362V1
Thanks to the big boss for the open source
 
(3) Compilation and use
After completing the above modifications, compile the kernel separately and burn it to get boot.img. Burn it into the Android image provided by Taishanpai (burn the kernel separately)
The attached boot.img is compiled separately from the kernel. Android can be burned directly and used.
 
2. Hardware part
The hardware part is to convert the 40p flex cable of the screen to the 31p used by Taishanpai and adjust the touch flex cable.
The touch part can be connected normally. The MIPI signal line should be made to be of equal length.
 
Note: Taishanpai's MIPI backlight current of 110mA may be too large for the recommended current of 20mA for a 3.0-inch screen. It is recommended to modify the backlight circuit. The calculation formula is as follows:

IOUT=0.2V/R (R=(R95xR96)/(R95+96)). IOUT = 20mA, therefore R = 0.2V/0.02 = 10Ω, meaning a 20Ω parallel connection.

So, the 3.6Ω parallel connection in the backlight circuit is changed to a 20Ω parallel connection (other similar resistors can also be used; I used a 22Ω resistor that I happened to have on hand).
The actual modification location is shown in the following figure.
 
The actual board diagram is shown in the following figure.