Device Tree Location in Debian

Hello,

I need to access the Device Tree File of BB-BONE-LCD4-01:00A1 make changes and recompile,
Can i get help about the location of the file and recompiling procedure.
it would be very helpful to me

The Version running on my Beagle Bone Black Rev C is “BeagleBoard.org BeagleBone Debian Image 2014-10-08 : Linux beaglebone 3.8.13-bone67”

``

https://github.com/beagleboard/linux/blob/3.8/firmware/capes/BB-BONE-LCD4-01-00A1.dts

It's "built-in" so you will have to rename it as something else to load it...

http://elinux.org/Beagleboard:BeagleBoneBlack_Debian#Loading_custom_capes

Regards,

Hello,

Thank you for your time and reply

Well i tried out by copying and Renaming the file to Root folder of BBB ,
just to test whether am I able to compile i have not done any modifications to the file yet,

Just Renamed the LCD4 Part to LCDA and executed Command
dtc -O dtb -o BB-BONE-LCDA-01-00A1.dtbo -b 0 -@ BB-BONE-LCDA-01-00A1.dts

I get
Error: BB-BONE-LCDA-01-00A1.dts:1.1-2 syntax error
FATAL ERROR: Unable to parse input tree

Once Again i clarify This is the same file i downloaded from the link you gave only renamed the file.

Am i doing correctly as you suggested ?

The Modification i need is to Enable 24BIT Support to the file by referring to http://elinux.org/24bit_LCD_for_BBB

Regards
Altaf

Hello ,

I Got the .dtb file complied , I made a mistake by only changing the File name but didn’t
changed the Part No argument in the file .

I then made the necessary Changes to enable 24 BIT. the reason i was doing this is to fix a Yellow Display Problem
But i still have the same problem. Any ideas or help regarding would be really appreciated and helpful.

Any help ?

Regards
Altaf

Does your lcd cape, actually have all 24 lines hooked up to support 24bit?

Regards,

YES They are all connected.

Did you modiefy xorg.conf to 24bit? usually it's in 16bit mode:

sudo sed -i -e 's:16:24:g' /etc/X11/xorg.conf

Regards,

No i didn’t modified that.

As per your instructionsI did thereafter now there no display i can see display initialized with black screen
and a small cursor binking on the TOP LEFT of the screen

Regards
Altaf Sunesara

Hello,

Any further help, if possible can you point to some more debug commands where I can share some more info that may be useful. I'm stuck can't get 24 bit display.

Regards
Altaf

Honestly, i haven't dove into the 3.8 tree in over a month or two.
It's so old, it's more of a waste of time as it's a kernel i really
don't care about anymore.

However on v3.14.x i got 24bit working on the Chipsee bbb-exp-c lcd..

http://elinux.org/Beagleboard:Capes_3.8_to_3.14#Chipsee_bbb-exp-c

dts:
https://github.com/beagleboard/linux/blob/3.14/arch/arm/boot/dts/am335x-bone-bbb-exp-c.dts

main include for bbb-exp-c
https://github.com/beagleboard/linux/blob/3.14/arch/arm/boot/dts/am335x-bone-bbb-exp-c.dtsi

panel:
https://github.com/beagleboard/linux/blob/3.14/arch/arm/boot/dts/am335x-bone-panel-1240x600-24bit.dtsi

Regards,

Hello,

Thanks for all your help and time I will check and get back with results.

Regards
Altaf

Hello, Robert

I have been assisted by you in getting the kernel 3.14 earlier yesterday in a different post where i faced RF KILL ISSUE. leaving that i need to test 24 BIT TFT with
kernel 3.14 ,

As suggested by you earlier I migrated to a 3.14 kernel, i read a lot things and searched about the Device Tree but i’m not understanding.
I referred to the post Redirecting to Google Groups
but still very confused, i had just got comfortable with Device tree in 3.8 and in 3.14 it seems its something different way.

How do i load the drivers in the kernel, parameter passing in uEnv.txt etc.
what is the location of the below mentioned files on BBB
what are the steps 1 by 1 for eg we will take BB-BONE-LCD4-01-00A1 to be loaded in the kernel as this was working in 3.8.

Earlier you pointed these files but i’m unable to understand how to get them loaded

dts:
https://github.com/beagleboard/linux/blob/3.14/arch/arm/boot/dts/am335x-bone-bbb-exp-c.dts

main include for bbb-exp-c
https://github.com/beagleboard/linux/blob/3.14/arch/arm/boot/dts/am335x-bone-bbb-exp-c.dtsi

panel:
https://github.com/beagleboard/linux/blob/3.14/arch/arm/boot/dts/am335x-bone-panel-1240x600-24bit.dtsi

Your assistance regarding this would be highly appreciated and helpful

Regards
Altaf

As overlays aren't enabled in v3.14.x you need to use a custom *.dtb for capes:

For the "BB-BONE-LCD4-01-00A1"

http://elinux.org/Beagleboard:Capes_3.8_to_3.14#lcd4-01-00a1

So you'd add:

dtb=<device>-lcd4-01-00a1.dtb

dtb=am335x-boneblack-lcd4-01-00a1.dtb

into /boot/uEnv.txt

Regards,