[U-Boot] sun50i: Allwinner A64: Add LVDS video support - question about how to proceed

Kamps, John-Eric John-Eric.Kamps at Honeywell.com
Wed Apr 24 07:01:14 UTC 2019

Hi all. 
I'm new in working with the community and where I can ask question about how something should be done. 

I need LVDS on the Allwinner A64 and checked the source code. 
There is the code for sunxi (A20 and so on) with the file "sunxi_display.c" 
and the new one for my sun50i (A64) "sunxi_de2.c". 
both are sharing files between each other but for sun50i the sunxi_display.c is disabled from kconfig for my chip. 

I see 2 ways to enable LVDS on sun50i, but I don't know in which direction the development should go. I can enable in KCONFIG that the sunxi_display could be also build for A64, but I think it has a reason why this is disabled and only the sunxi_de2 system should be used, or?

So going the way that there was a patch to enable the LCD over the sunxi_de2 file (git: 1d7eef3f3fbd82796a4ced3adda0a9041393141d). I can add the needed pinmux settings in the corresponding files and enable in kconfig that there is also the menu to setup CONFIG_VIDEO_LCD_IF_LVDS and CONFIG_VIDEO_LCD_IF_PARALLEL like for CONFIG_VIDEO_SUNXI. Also with the other settings there.

Is these the correct way to add them?

If yes how the backlight will be used and added? Because the sunxi_display.c has it integrated with getting the extra settings from menuconfig. Is it needed to add the same settings as well to sunxi_lcd.c like in sunxi_display.c? Or is there a different system to enable backlight in the future from the information of the dts-files? If yes did someone can give me a hint where I can find something about it?

Thanks a lot
Kind regards
John-Eric Kamps

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