Device Tree Location in Debian

[Altaf]

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"

[Robert Nelson]

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,

--
Robert Nelson
http://www.rcn-ee.com/

[Altaf]

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

[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

[Robert Nelson]

On Fri, Oct 17, 2014 at 10:07 AM, Altaf <altaf.s...@gmail.com> wrote:
> 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.

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

[Altaf]

YES They are all connected.

[Robert Nelson]

On Fri, Oct 17, 2014 at 11:04 AM, Altaf <altaf.s...@gmail.com> wrote:
> 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

[Altaf]

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

[Altaf]

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

[Robert Nelson]

On Tue, Oct 21, 2014 at 9:51 AM, Altaf <altaf.s...@gmail.com> wrote:
> 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.

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

[Altaf]

Hello,

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

Regards
Altaf

[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 https://groups.google.com/forum/#!topic/beagleboard/Mff1dl1GuAc 

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

On Tuesday, 21 October 2014 20:29:42 UTC+5:30, RobertCNelson wrote:

On Tue, Oct 21, 2014 at 9:51 AM, Altaf <altaf.s...@gmail.com> wrote:
> 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.

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.

[Robert Nelson]

On Thu, Nov 13, 2014 at 9:05 AM, Altaf <altaf.s...@gmail.com> wrote:
> 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
> https://groups.google.com/forum/#!topic/beagleboard/Mff1dl1GuAc
> 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.

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