Linux: AM335x LCD colours swapped

sankar salla14

Prodigy 140 points

Tool/software: Linux

Hi All,

I am working on am335x customised board with linux version 4.4.19.

I am facing problem with RGB colour issue.

RGB lines are swapped in H/W,can you please tell me any possibility is there from software side for swap RGB to BGR.

Thanks & Regards,

Sankar.

over 7 years ago

0 Biser Gatchev-XID over 7 years ago

TI__Guru**** 393215 points

Please see Errata Usage Note 3.1.1. I will ask the software team to comment if there is a software workaround. They will respond here.

0 Manisha Agrawal over 7 years ago in reply to Biser Gatchev-XID

TI__Mastermind 22946 points

As Biser pointed out, AM335x has silicon errata which causes the colors to be swapped for RGB565 or RGB888 depending if the LCD controller is wired for RGB888 or RGB565 mode.

To take care of this errata and help enable proper display of colors for both RGB565 and RGB888 mode, "blue-and-red-wiring" priperty is added in device tree settings for lcdc. It can be set as "straight" or "crossed" based upon the the hardware wiring. Example settings below -

&lcdc {
blue-and-red-wiring = "straight";
status = "okay";
};

Make sure you are using linux driver from Processor SDK version 4.1 and above as the configuration support inside lcdc driver via device tree got added in SDK version 4.1.

0 sankar salla14 over 7 years ago in reply to Manisha Agrawal

Prodigy 140 points

Thanks for the reply.

Can you please tell me,which kernel version this support is added ?

Thanks & Regards,

Sankar.

0 Manisha Agrawal over 7 years ago in reply to sankar salla14

TI__Mastermind 22946 points

Hi Sankar,

Kernel version is based out of 4.9.41, but the fixes are applied on top of that and hosted here. You can do git log and search for "blue-and-red-wiring" and look for those commit ids.

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Linux: AM335x LCD colours swapped